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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Crist Rigotti on December 28, 2014, 05:14:49 PM
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Time for another build log. I have my shop set up enough to start building again after the move to Texas.
This time it will be a Legacy 40 electric. Back in 2001 Allen Brickhaus contacted me and asked if I would be interested in building one of the prototypes the other being built by Watt Moore who Allen used to CAD the drawings. I powered that one with a Stuka Stunt OS35FP and a 12 inch Bolly prop. The plane flew very well for me and it was retired in 2006 using an OS 46 LA. That airplane was used to fly my first full pattern in August of 2001 with Floyd Layton coaching that day.
Allen was my mentor and good friend. His gentle coaching and encouragement has help me through the years. After every contest he would ask me what went well and where I thought I could have done better. At the end of every year we would talk about the year and the new flying season ahead along with what airplane I intended to build over the winter. When I started to compete he would tell me that there are only 2 important things on contest day; Breakfast and Dinner, everything else in between was fun. I often would think that on contest day especially if it didn't go well. And there were many that didn't. I knew what he meant and have always kept that close to my heart. I miss Allen and this build thread is dedicated to his memory one year after his passing. He touched a lot of people and I hope through this build thread, I can stir some of those good memories for you.
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This version of the Legacy 40 (L-40) retains the same size and outline as the prototype that I built. Some of the stats are:
WS- 54 inches
WA - 571 sq in
Flap volume - 16.41%
Tail Volume - 27.9%
Weight - 50 oz
Stab area - 90.5 sq in
Elevator area - 68.84 sq in
Wing offset - .5 in
Flap area - 93.76 sq in
The changes I've made are all internal except 1. They are:
Foam wing
Landing gear moved into the wing
Molded top blocks
Canopy moved aft 1/2 inch to accommodate the battery hatch
2 1/2" wheels instead of 2"
Hinged rudder for either a Rabe or adjustable rudder
Eliminate the "engine" cowl
Increase the fuselage width 3/8" to facilitate electric cooling
I've included a pdf of the full size drawings that I'll be using along with my weight and balance chart, my electric worksheet and my building notes and weight chart.
I'll try to be very specific as to the density of the balsa wood I'm using for each part, the type of glue, and nearly a step by step as we go along. Please ask questions and leave comments as you see fit.
EDIT: I added a note to the plan that states the "Top" view is really the "Bottom" view. This is the way I build my fuselages on the bench using my jig. I build them upside down. Hence the upside down view on my drawing.
Another Edit: I increased the scaled width of the landing gear to match the full size Legacy and created a pdf in ledger size rather than full size till the build is finished.
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Crist,
Looking at your ledger plans I'm trying to figure out what the template on the bottom of the plan is. Maybe the bottom view of the plane? Will the battery tray be vertically adjustable? I see holes in the tabs of the battery tray.
Bob
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Crist,
Looking at your ledger plans I'm trying to figure out what the template on the bottom of the plan is. Maybe the bottom view of the plane? Will the battery tray be vertically adjustable? I see holes in the tabs of the battery tray.
Bob
That template would be the 1/8 Lite-Ply wing spar. I could adjust the battery tray by using shims under the tray. The holes are for the #2 servo mounting screws that will hold the tray in the fuselage.
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LL~ Crist is this another build a log? Beating by proxy. LL~
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LL~ Crist is this another build a log? Beating by proxy. LL~
Well Bob, I guess it is! Looking forward to getting it done now that I'm pretty near settled in here in Texas. A good group of flyers from these parts and expecting some good advice on what to improve. Have a Happy New Year.
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I have the foam wings all cut out. Each panel weighs 43 grams. They are triple cored and the leading edge is sectioned for the wing mounted landing gear. I'm under the weather lately with the crud. Progress has been slow. Feeling a bit better today. Pictures and more info later.
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Hope you start feeling better, since your retired are you going to start cutting foam wings again ?? GO HAWKS !!
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Hope you start feeling better, since your retired are you going to start cutting foam wings again ?? GO HAWKS !!
Thanks Lee. Maybe on the foam wings.
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Crist,
Looking forward to following your build thread. Hope you're staying warm down there in Texas. We're freezing up here in Illinois brrrrrrrr.
Dennis
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Crist,
Looking forward to following your build thread. Hope you're staying warm down there in Texas. We're freezing up here in Illinois brrrrrrrr.
Dennis
Good to hear from you Dennis. Staying warmer than you, that's for sure! :)
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Here is a picture of the foam core that I cut. The wing will use a wrap around sheeted leading edge. After cutting the airfoil shape I sand the cores using 180 grit sandpaper to get rid of the "cotton candy" crispies and to knock off the LE leading of the hot wire. After sanding the cores change on how they feel. They go from the "hairy crispy" state to a soft velvet smooth feel. I then mark out the location of the spars and the LE ribs. The LE rib locations are the outer edge of the outer rib and the inner edge of the inner rib. The foam between those 2 cuts will be trimmed down to fit between the ribs once they are glued in.
The spar slot is then cut using a 1/16 ply guide that has approximately 1/8 slot and held in with 1/8 aluminum roofing nails. The slot is then cut using a small bow with nichrome wire. I then "horizontal bore" near the center of each the 3 cores on each panel. I use a 3/16 4 foot rod that I heat the end with a propane torch. I have the bench marked out the "travel" of the rod and align the center marks of the core piece with the bench mark. I then heat up the rod and twist it while inserting it into the core. I only go half way. I do this for each of the 3 cores starting at the tip. I then turn around the wing panel so the rod goes into the root and meet the hole already half drilled through. Same procedure is used till the rod meets the other holes. Once done I then put my templates on the wing panel and using a 1/8 x 1/4 x 36 inch piece of spruce I then thread the hot wire through the holes and hook each end back up on the bow. BTW, I use .020 stainless steel safety wire on my long bow. I turn on the electricity using a foot switch and proceed to cut the core. I repeat this 3 times for each panel. On the inboard panel I also add a notch to the spar to allow lead out adjustment.
Once the wing panel has been cored, I then make the cut on the LE for the landing gear ribs. I tape guides in place and use my small bow to do this. Once done I then cut the outboard panel down 1/2 inch to provide my 1/2 inch wing offset. Each panel weighs 43 grams.
Next up the Leading Edge sheeting!
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I used 6.3# 1/16 balsa for the LE sheeting. This will be the wraparound type LE. I used a 4" wide piece of nice "A" grain wood then cut it into 2" strips 26 inches long. I then used 2 pieces of 3" balsa on each side the the 2" balsa. I try to use "A" grain because it goes around corners (the LE!) easily. The root is about 8" wide and the tip is about 6 3/4" wide. I taper the the 3" pieces to obtain the tip dimension needed. This tapered side goes against the 2" LE piece. This allows the grain of the 3" pieces to be parallel to the spar. I think this gives me a stronger wing this way.
After trimming the pieces to size, I then edge sand the sides that will be glued together. I use a 4 foot level with some sticky backed sandpaper on one end and clamp it to my workbench. I then clamp a 1/4" balsa in front of the level. This is done to get the piece that I'm going to sand up from the table and on to the sandpaper. The picture should help. I then sand the edges carefully. It only takes about 6 passes to produce a good joint.
I then edge glue them together using Bob Hunt's method of using thin CA glue and masking tape protected fingers. I do this over wax paper to prevent the skins from sticking to the bench. Once glued, I mark what side goes in (usually the side I just applied the glue to) and sand the skins smooth. Not too much, but just smooth. I then draw a center line down the middle of the 2" center piece for alignment when I mold the LE. Each skin just before molding weighs 19 grams.
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Crust,
Thanks for taking the time to post your build log. I look forward to each installment. I find this very helpful.
Zuriel
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Crust,
Thanks for taking the time to post your build log. I look forward to each installment. I find this very helpful.
Zuriel
Thanks Zuriel.
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Let's add the spars to the wings. I use 1/8 Lite-Ply for the spars. I use 3M #77 spray glue and glue the plan onto the Lite-Ply. After cutting out on my jig saw and hand filing the holes. I then used my disc sander to sand the out edges to their final size. I then use some acetone and a paper towel and dab the plan sheet to loosen the glue to remove it from the Lite-Ply. A little sanding and they are ready to glue in.
A fit check then is in order. I glue it to the foam panel using my Pica-Gluit for foam. This stuff works great. I then tape into position and place into the cradles and weight them down till dry.
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After the spars are dry I then glue on the inboard portion of the LE. I first cut out the foam for the bell crank then I dry fit the LE piece. I then mark the bell crank cutout and cut the foam. Once done I glue on the LE piece using Pica-Gluit carefully aligning the foam on the root edge and centered on the spar. Again this is taped into position and weighted down in the cradles to dry.
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BTW, I almost forgot to mention that I use 1 sheet of newspaper and wrap each of the "plugs" from the 3 sections that have been cored. By wrapping them with newspaper, I make up for the hot-wire kerf. They now fit just a bit snug and when weighing down the cradles, the wing panel retains its shape.
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That's a neat tip about the newspaper with the core plugs. I would have thought the hot wire kerf would take more than just one layer. So where do you get the Pica foam glue you mentioned ?
Really enjoy following your builds, thanks for making the extra effort to post. I did this a couple of years ago with my RMD-3 build on the Ringmaster BrotherHood forum, then shortly after it was done their server crashed and it was lost.. :'(
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That's a neat tip about the newspaper with the core plugs. I would have thought the hot wire kerf would take more than just one layer. So where do you get the Pica foam glue you mentioned ?
Really enjoy following your builds, thanks for making the extra effort to post. I did this a couple of years ago with my RMD-3 build on the Ringmaster BrotherHood forum, then shortly after it was done their server crashed and it was lost.. :'(
Allan,
Unfortunately the Pica-Gluit line is no longer produced. I only have the 1 bottle of the foam stuff ( it is listed as a acrylic copolymer emulsion) , but 3 of their wood-to-wood glue (it is listed as an aliphatic). The foam glue reminds me of Pacer's 560 canopy glue.
I tried 2 sheets of newspaper and it got too thick. Instead of layers I should have said sheets.
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I make up my wing trailing edges using 2 pieces of 3/16 x 3/8 6.8# balsa and 1 piece of 1/32 x 3/8 13.5# balsa. The 1/32 wood is what I had laying around so I used it. I've used anywhere from 6# to 15# 1/32 balsa. The 1/32 balsa is used to from the hinge slots when I laminate the TE.
On one piece of the 3/16 balsa I layout the hinge center and the mark the root location. I then measure out 3/8 inch from each location to mark out each hinge slot. I then cut the 1/32 balsa to length. I use my 4 foot level and some wax paper and then I glue on the 1/32 pieces using medium ca. Once that is done, medium CA is applied to the 1/32 pieces and the top piece of 3/16 is positioned and pinned in place till dry. Note that I place the pins where the hinges will go so as not to interfere with the top piece when gluing.
When dry the TE piece is trimmed to the root mark and cleaned up a bit using my 2 foot sanding bar clamped in the vise.
Then I draw a line 3/32 from the edge all along the trailing edge of the TE. This mark is used as a guide when shaping the TE. It assures symmetry and a straight TE. This mark is just slightly "higher" than really needed but the last thing I want to do is "round" this piece. I want it just a little high so when I glue on the TE sheeting I get a good tight fit. You'll see in the other pictures later on what I mean.
Eagle eye people will notice that right at the root there isn't any 1/32 balsa. This is done on each TE and the slot will be used to help align the wing halves when joining. I'll use a small strip of 1/32 ply for that.
Each TE piece weighs 10 grams ready to glue on the foam wing panel.
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Now that the spars and the the foam LE are glued in, it's time to make up and install the false ribs for the landing gear. I use 1/8 Lite-Ply for the ribs. After cutting out and final sanding they are ready to install.
I use Pica-Gluit for foam and used masking tape to hold them into position.
Once dry I then trim down the outboard end of the last piece of LE foam that needs to be glued in. I trim the outboard edge because this will allow the most foam to be used and thus allow some sanding to smooth the entire rib/foam assembly. Again Pica-Gluit was used and some masking tape was used. As usual it was weighted in the cradles till dry.
I then sanded the whole assembly till smooth.
I then marked out the location of the aft edge of the landing gear plate. I then drew another line 2" aft. I also located the outer edges of the false ribs. These lines will be used to locate the cutout for the landing gear plate after sheeting.
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Time to mold the LE sheeting.
I soak the sheeting in the bathtub using only hot water - no ammonia. While the sheet is soaking I lay out 2 strips of masking tape about 2 inches from each end of the sheet. These strips will be used to "locate" the sheet on the form. BTW, you really don't need a separate form. You can use the wing itself only after you've installed the TE. The balsa trailing edge will prevent the foam from collapsing from wrapping the sheeting to the foam. Do this before you shape the TE. This way if the wrapping does crush the wood TE slightly, it won't matter because you'll sand it away.
After the sheeting has soaked for about 20 to 30 minutes I remove it and scrape off the excess water with my fingers. Then I wipe it with some paper towels. I place the sheeting over the masking tape and position the mold form on the center line of the sheeting. I then wrap the sheeting, from the LE aft up onto the form. I then hold it in place with the masking tape. I do the root end first. Then I do the tip. Once satisfied with the placement of the sheeting on the form, I wrap the the whole thing tightly using strips of bed sheet about 3 inches wide (thanks Al Rabe for this tip). I use bed sheets instead of an ACE bandage because the bed sheets won't leave a weave pattern in the balsa wood like an ACE bandage does. I usually clamp 1 end of the strip to my workbench and the start winding on the form from the root end first. The wrapping is held in place with masking tape.
I then placed it into the oven set at 170 degrees to "bake". I usually just place it over a hot air register but in the new house they are all in the ceiling. I'll bake them for an hour or so.
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Crist, this is a great thread that I will have to keep track of.
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Time to sand/shape the TE. First thing I do is run a piece of 1" masking tape about 1/4 inch forward of the TE. This is used to protect the foam during sanding the TE. I then use my Master Air Screw plane and plane down the TE just to the top of the ink line. I then sand the TE/foam section till smooth using a 11" sanding bar being carefull not to "round" off the TE. I want the TE straight to get a good joint when adding the TE sheeting. I then remove the tape and do the final sanding down to the bottom of the line. Flip the wing panel over and repeat.
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The next step I took was to draw out where the LE, TE, Center Section, and Tip sheeting go. I used a ball point pen and just drew on the foam itself. These will be my guidelines when sizing and attaching the sheeting. I then placed the LE sheeting on the wing panel and marked the spar line and the root and tip rib locations. I trimmed the sheet on the spar lines and just a little longer on the root and tip ribs. Each LE sheet after trimming weighed 17 grams.
I then mixed up about 3/4 ounce of my MGS 285 epoxy that I use to glue skins on the foam. I got this stuff from work which was left over from a job we did. I dribble the epoxy inside on either the top or bottom and I use my sheeting tool to spread it around on the one side. This tool is 1/16 plywood about 3 inches wide with the corners rounded to prevent it from digging into the balsa wood. I also file a 1/32 deep notched about every 3/16 inch using a small triangular file. I then scrape all the epoxy I can off leaving small rivulets of epoxy. Then I repeat the same for the other half. I then weighed the sheeting to see how much epoxy I used. I used 7 grams of epoxy.
I then placed the LE sheeting over the wing panel and used a straight pin (thanks Bob Hunt) to located the center line of the sheet to the center line of the the foam LE. I then used 5 pieces of 1 inch masking tape to hold into position. In the cradles they go with a piece of 1/16 balsa to shim the core in the cradle. I used wax paper on each side of each wing panel. Then weighted the whole shebang till the morning.
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The TE, tip, and center sheeting are all made from 7# 1/16 sheeting. I trimmed the sheeting to size and then glued the 3 pieces together using CA. I then trimmed each sheet to just a little over size. I wet the sheeting that mated up to the LE and the LE sheeting too. This will cause the the joint to be very tight when dry (thanks Bob Hunt). I then masked off where the sheeting will be overlapping the TE. I used my MGS 285 epoxy and my spreading tool. I then removed the masking tape and used Pica-Gluit to lay down some glue for the TE and on the LE joints. I use the Pica-Gluit because it sands great and doesn't leave a hard edge. I then placed it on the wing panel and used some masking tape to "pull" the LE joint tight. Then the whole thing gets weighted down till morning. The Sheeting weighed 17 grams per panel and I used 6 grams of glue per panel.
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I added the 1/16 x 1/4 cap strips today using 6# wood. I used Pica Gluit and Tom Morris weights.
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I sanded the cap strips and sheeting lightly and now for the tip weight box fabrication and installation.
The box is made from 1/8 Lit-Ply sides and 1/8 Birch ply bottom. The side dimensions are 1 1/8 tall and either 1 or 7/8 inches wide. These are glued using thin CA to form a rectangular box. The long side will be butted up against the forward face of the spar. I then trace this box onto the 1/8 Birch ply bottom. I trim and then drill a 5/32 hole in the center for a 4-40 blind nut. I glue on the bottom with then CA and sand the entire assembly smooth. I then glue on a 1/64 ply skirt onto the top of the box. The ply is 3/4 tall with a 3/8 overlap onto the box.
I then locate the forward face of the spar using pins pushed down from the top of the wing. When located I invert the box and trace around the perimeter. I then cut out this section. I then dig out the foam underneath the box. I then added a small 1/8 shim on the aft edge of the cutout for the box to sit onto. This regulates how deep the box goes into the wing. I try to have the aft 1/64 skirt just above the wing sheeting. I then mix up some 5 minute epoxy and micro balloons. I dab some in the bottom of the cutout and also on the front face of the spar. I then push the box into the wing. I then use my Pica-Gluit around the skirt and the sheeting. Do NOT use CA. This will melt the foam away! When dry I mask off the wing and sand down the skirt to the sheeting.
Continued on next post.
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I make the top using 1/8 5-ply Birch ply and 7# 3/8 sheet. 1/4 sheet would probably do. I fit the 1/8 ply into the top of the box. I then mark off the center and drill a 1/8 hole. Then cut the 3/8 sheet over size and drill a 7/32 hole in the center. Use medium CA and glue in 7/32 aluminum tubing into the hole. When dry cut off the tubing and sand flush with the 3/8 sheet. Use a 4-40 socket head screw to locate the 7/32 O.D. tubing over the hole in the 1/8 Birch ply cover. Glue on the 3/8 sheet using medium CA. Thrim the sheet flush with the outer edges of the cover. Install into the weight box and I mark the airfoil shape on all 4 side. I then use my disc sander to get the 3/8 sheet close. Install the cover using the 4-40 screw and do a final sanding to match the airfoil.
On my cover I then lined each side with 1/32 bass wood to give and keep a nice crisp edge. I'll Monokote the wing and I don't want to roll the edge.
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With the wing tips coming up I decided to make the adjustable lead out guide. I used 3 pieces of 3/32 basswood. The middle piece has the grain going vertical while the other 2 has the grain horizontal. I use medium CA for this. Once glued I draw a center line and lay out the holes for the eyelets on 1/4 inch centers. I drill the holes and I create the slot using my band saw. I then use a small piece of 1/64 ply to "plug" the slot on the end from the band saw blade entrance. I then use 120 grit sandpaper to enlarge the slot so the lead outs can slide for the adjustment. I then soak the holes and slot with thin CA. The holes and slots are cleaned up and the guide is trimmed and sanded to final size.
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Time to do the landing gear mounts. I basically followed Bob Hunt's method.
The base is 1/8 Lite-Ply with 1/8 basswood and balsa wood. I used medium CA to build this. I used some 1/2 x 3/8 hard maple and epoxied and clamped to dry over night. I then trimmed the maple to size and installed the 4-40 blind nuts. I then used a #30 drill for the 1/8 music wire landing gear. I then chamfered the hole to accommodate the bend radius of the 1/8 music wire. Then the assembly is epoxied into each wing panel. When dry I installed a 3/8 balsa piece on the inboard end and a 1/4 balsa on the outboard end. The forward and aft sides were lined with 1/8 balsa. These were glued in with Pica Gluit. I then made the removable hatch using 1/32 ply and 1/4 balsa. I lined the the 4-40 screw holes with 7/32 O.D. aluminum tubing. The hole thing was sanded down to match the airfoil.
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Really cool!!!!
Marcus
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Thank you Marcus.
I cut 1 inch holes in each rib bay in each cored section to allow the air to flow around especially because I use Monokote on my wings. This is NOT done to reduce weight! I layout the centers and place the my template on the center line and use an old 30 watt soldering pencil to go around the the template melting the foam as I go. I do this for the top and bottom of each wing panel.
Total weight saved by doing this was 2 grams per panel. Never cut out all the foam between the cap strips! You will greatly weaken the foam wing and will only save a few grams. The "return on investment" is not good! I only cut the foam away as shown. I could pierce each bay and get the same result of venting each bay.
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I use Tom Morris hardware for the push rods. I also use 7/32 O.D. aluminum tubing as a ferrule to prevent the Cf push rod from splitting.
After measuring the CF tube to length I roughed up the ends with some 120 grit sandpaper. I clean the CF tube and the threaded ends with rubbing alcohol. I cut the ferrules 3/4 inch long. I leave one end "rolled" over from the K&S tubing cutter that I have for the RH threaded ends and remove the "rolled" over end on the ferrule that will go on the LH threaded end.
I use JB Weld to glue each threaded end to the CF tube. I use a round toothpick to spread some JB Weld in the inside and then on the the RH threaded end. I then insert the RH threaded end into the CT tube. I then spread the JB Weld around on the CF tube where the ferrule will go and also up onto the rounded portion of the RH threaded end. I then put the ferrule over the RH threaded end and onto the CF tube. The ferrule will cover the rounded portion and onto the CF tube. I then wipe everything clean and inspect to be sure the RH threaded end is pushed all the way into the CF tube.
On the LH end of the elevator push rod I spread glue on the outside of the CF tube, then slide the ferrule onto the tube before I insert the LH threaded end. It seems that the LH end is just slightly larger in diameter than the RH ends. When all done I clean up the push rods and ensure that the ends have not push out and remain "seated" into the CF tube. I let them dry overnight.
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Full length turtledeck on this one Crist? I always thought that was a good look on your old one. y1
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Full length turtledeck on this one Crist? I always thought that was a good look on your old one. y1
Wayne,
I debated that option and I agree I like the look of a turtledeck. But probably not because I want this to be pretty near what the prototype was. Though, I'm not done with the fuse either!
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Gotcha, at least we know what color it will be. :##
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Gotcha, at least we know what color it will be. :##
Like this maybe?
Yup, on the colors!
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Yeah but I'd move the windscreen profile back a bit. Copying you're old one would be perfect IMO, right down to the canopy framework detail and overall paint scheme. y1
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Yeah but I'd move the windscreen profile back a bit. Copying you're old one would be perfect IMO, right down to the canopy framework detail and overall paint scheme. y1
Wayne, which airplane do you mean?
How's this, better? I think so.
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Struggling a bit with the wing tips. Should have those worked out tonight or tomorrow. Stay tuned for pictures.
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Wayne, which airplane do you mean?
The one you sold at Polk City a year or two ago, the top half of the fuse was solid red and the canopy outline was somewhat similar to a P-51B. I think it may have had an ST.51 in it?
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The wing tips are done except final detail sanding. They were made up from 3 layers of 1/8 6.7# balsa. These were laminated using medium CA and trimmed very close to the final outline. The LO guide was then glued in using Pica Gluit. Once dry the tips were glued on to each panel again using Pica Gluit. Once dry I added some LE blocks and some TE filler from 1/8 sheet. Once dry these were carved and sanded to the shape as shown.
The struggle I had was whether I wanted to use the LE blocks or not. I let it stew for awhile and decided on using them.
I still need to elongate the outer most hinge slot that extends into each tip.
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I had a bell crank and lead out assembly form another airplane so I decided to use it. My bell cranks are home made out of 1/8 phenolic with a 1/8 music wire post. I triple up the thickness (3/8) where the post goes through the bell crank. I used 1/16 annealed brass tubing to bush the LO .027 wire. I also solder washers to center the bell crank on the post. I bolt on the ball link using 4-40 hardware.
I then use 5 minute epoxy to glue it into position in the LH wing panel. I already cut the wing panel for the flap push rod which will be inserted once the wing is glued into place in the fuselage.
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I carefully joined the wing panels tonight using 15 minute epoxy and a small amount of microballoons.
I then prepped the 6 circles of medium silkspan that will be used to reinforce the center section both top and bottom. They are 4, 6 and 9 inches in diameter. After cutting them out with my scalpel, I then "feather" the edge with an Emory board. This is done to prevent a "hard" edge on the silkspan circle. I'll lay down the 4 inch circle centered over the bell crank post, then the 6 inch circle centered over the bell crank post, then finally the 9 inch circle centered over the center section sheeting.
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Today I doped down the 3 silkspan circles on each side with SIG Nitrate dope.
I first thinned the nitrate dope 25%t that is 25% thinner 75% nitrate dope. I then brushed on 2 coats onto the bare wood center section. Each coat was followed by some light sanding with 320 grit sandpaper. I then moistened the 4 inch circle and laid it flat over the bell crank post. Then I brushed on 1 coat of nitrate dope. Let it dry and sanded lightly, especially around the edges and applied the 2nd coat of nitrate dope. When dry I sanded the edges to further feather them and then applied the 6 inch circle in like manner. Then the 9 inch circle likewise. Then added 1 more coat of nitrate dope to finish it off. Once dry some more light sanding and it will be done.
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The wing is done being built. Some minor detail sanding needs to be done just before covering. The weight of the wing as shown is 295 grams.
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Lookin' good Crist! y1
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Thanks Wayne.
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I started on the stabilizer today. The TE is made up using 2 pieces of 3/16 x 1/2 7.9# balsa and 1/32 balsa to form the hinge slots. These were edged up against my 4 foot level to get a nice straight edge. I marked the center line and the hinge locations. Then cut the 1/32 balsa to size, pinned the bottom piece, glued the 1/32 balsa using medium CA, then glued on the top piece, again using medium CA.
Once dry I then cut a piece of .007 unidirectional CF to length and just over 3/8 high. I then used medium CA to glue the CF to the forward face of the TE. This will give great strength with little weight gain.
I then glued the LE ( 2 pieces of 3/16 x 1/2 balsa) in a like manner but I used Pica Gluit because the LE will be sanded to a longer "taper" when shaping the LE and I needed a glue that will feather well. When dry the LE pieces will get the CF treatment as well.
I also glued the 3/16 balsa and 1/32 balsa tip pieces using Pica Gluit.
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Any more?? 8)
Marcus
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Yeah Marcus. I just finished the stabilizer.
After pinning down the LE and TE, the tips were fitted and glued in using Pica Gluit. Once dry I lifted the frame and fitted the bottom 1/16 9# center section sheeting. That's right, 9# stuff. Between using 7# or 9# sheeting there was only 1 gram difference. BTW, this stabilizer has turned out very stiff! Then the ribs were added using 7# 1/8 balsa. I use 1/8 balsa here because it hold up much better than 1/16. It also provides a much stiffer structure. I use some 3/32 hard brass tubing to cut the air holes in each of the ribs. You'll notice the 1/4 hole in the bottom sheeting. This will allow the air to move in/out of the stab during temperature changes.
When gluing in the ribs, I used 2 layers of masking tape on the bottom of the frame. This ensures that the ribs should fall below/above the frame. It'll make sanding a whole lot easier to sand "down" the ribs to the LE/TE. I really don't like it when a rib is below the LE/TE. I used thin CA to glue in the bottom sheeting and ribs. Medium CA for the top sheeting.
Once dry I sanded the top and bottom smooth and shaped the LE. TE and the tips. I shaped the LE with an ellipse section rather than a 1/2 round section. Dennis Van DeKuur showed me on his full size Legacy. He beat me plenty of times with that Legacy and now that his secret is out and incorporated in this Legacy.....look out Dennis!
When done sanding smooth I used some thin CA to soak and strengthen the TE by the tips. This prevents them from "rounding" and gives a nice crisp edge.
The stabilizer looks dirty in some pictures due to the .007 CF used along the LE and TE.
The weight of the finished stabilizer is 44 grams.
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I built the elevators in a similar manner as the stabilizer.
The LE and TE are made from 2 pieces of 1/8 x 1/2 8.6# balsa and 1 piece of 1/32 6# balsa. They were laminated using medium CA glue. The tips and center section sheeting were laminated from 1/8 7# balsa and 1/32 balsa using Pica Gluit. The ribs are from 1/8 7# balsa with 3/32 air holes. These were glued to the LE and TE using thin CA glue. The LE, TE, tips, and center sheeting were glued together using Pica Gluit.
I then made up some elevator horn clips using 1/8 Lite-Ply and 1/8 aluminum tubing all glued together with medium CA glue. After bending the elevator horn I used it to "space out" the horn clips onto each elevator while the elevators are held in place with 3/4 wide x 7/8 long 1/32 ply to simulate the hinges. I then used a triangle to be sure the horn clips are 90 degrees to the LE. Once the slot is cut the horns are trimmed to size and glued to each elevator using thin CA glue. I also capped the root end with some 1/32 basswood. The right hand elevator also incorporated a "pocket" ( 1/16 x 3/8) for a Rabe rudder linkage horn. The tips are trimmed to length and the elevators are sanded smooth and rounded where needed. Again I used some thin CA glue to strengthen the LE out by the tips to maintain a crisp corner.
Between the stabilizer and the elevators their weight are spot on. These turned out to be very stiff indeed.
The elevators shown here are 28 grams.
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Just an update. I'm waiting for the fin and rudder lamination to dry overnight, then I'll post about those.
Also I'm gluing on the 1/64 fuselage doublers tonight. More on that tomorrow as well.
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The rudder and fin are finished except final detail sanding before covering. Both are made from 2 pieces of 1/8 6.5# balsa and 1 piece of 1/32 5# balsa. These were laminated using my MGS 285 laminating epoxy.
Once dry, they were cut to size and sanded to shape. You'll notice that I capped the top of the rudder and the fin with 1/32 basswood to give a nice crisp edge.
The fin weighs 15 grams and the rudder 3 grams.
On to the fuselage!
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The fuselage sides are made form 3/32 6.5# balsa with a section of 7.5# balsa spliced on to make the final length. This spliced piece is on the nose area because that's where the doubler goes and helps keep the splice strong. Pica Gluit was here. The 1/64 ply doubler was epoxied on using MGS 285 epoxy. When gluing on the doublers the nose was raised 1/4 off the bench to create the flair into the spinner a lot easier. The battery shelf hardwood blocks were glued in using 15 minute epoxy.
I trued up the top of each fuselage side then used my drawing side and top view to locate the formers and wing/stab cutouts.
On to making formers.
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I make the formers using the 3M 77 glue the plan to the balsa method. F1 is made from 1/8 G-10 fiberglass printed circuit board without the copper. F2 and F3 are 1/8 Birch ply, F4 thru F7 are 1/16 cross grain 11# pound balsa ( that's what I had and wanted to use it up!), F8 is 1/16 balsa and a 1/64 ply laminate glued with medium CA, F9 thru F11 is 1/16 7# balsa. F8 uses the 1/64 ply because of the stab mounting and the tail wheel area.
After cutting out the formers, I use some acetone and a paper towel to dab the plan and then it peels off the balsa. A quick wipe of the balsa with acetone and some light sanding and they are ready to go!
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The fuselage is drying in the jig tonight.
I cut triangular shaped holes every so often along the center line of the fuselage plan. Then when I tape it to the jig I can line up both center lines. When lined up a piece of masking tape over the hole and onto the bench to hold it into position. Then covered with wax paper. I made the jig myself, but it is fairly standard type.
I used thin CA to glue in the formers and 15 minute epoxy to hold in the G-10 motor mount. While the fuselage is in the jig, I also added the aft most 2 angled formers. I couldn't do the forward most angled former because the wing needs to be glued in first.
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That's very good!!!!
Marcus
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I added the 1/2 Tri stock to the nose using thin CA and the aft motor mount pieces using 15 minute epoxy for strength. I then sanded down the top, bottom and "cowl" slope to match the fuselage sides.
The tail wheel mount is made using 2 pieces of 1/16 ply clued together with medium CA and a piece of 3/8 square hard maple. I use .078 wire for the tail strut. The lower pieces were spaced using some .078 music wire. The tail wheel mount will be epoxied in.
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Man, that looks great Crist! What do you use to cut the G10?
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Looking good Crist! I have to confess that I have not followed you thread as diligently as I should have. I presume you are front mounting the motor. I too wonder what you used to cut the mount. I ruined a bandsaw blade cutting that G10 a while back!
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Thanks Jason and John.
I used my trusty Dremel Moto-Shop 571-4 jig saw. And yes, I ruined a blade to cut it! I used my Delta band saw to rough out the outsides, then a quick pass on the disc sander. Then over to the jig saw, then finally hand files and Emery boards. Yes, the G-10 was hard on all of them.
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Thanks Jason and John.
I used my trusty Dremel Moto-Shop 571-4 jig saw. And yes, I ruined a blade to cut it! I used my Delta band saw to rough out the outsides, then a quick pass on the disc sander. Then over to the jig saw, then finally hand files and Emery boards. Yes, the G-10 was hard on all of them.
Crist,
I used a carbide bit for the Dremel tool (per Bob H. suggestion) and a carbide blade for a hack saw that I picked up at a local hardware store. Both made fairly quick work of it, and then the disc sander and so on.
James
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Crist,
I used a carbide bit for the Dremel tool (per Bob H. suggestion) and a carbide blade for a hack saw that I picked up at a local hardware store. Both made fairly quick work of it, and then the disc sander and so on.
James
Thanks for the info James!
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Mystery item for the day. What is it and what is it used for?
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The tail wheel mount epoxied in.
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More work on the nose today.
I decided to cut off the fuselage sides even with the forward face of the motor mount. I thought it would be easier to glue in the 7/16 cross grain balsa "filler" to a flat surface rather than try and taper it to fit. The cowl slope was added first then sanded flush at the nose. The aft portion was left because it will get nicked and dented till I'm ready to do the bottom. Then the top block was added and again sanded flush with the motor mount. Then the cross grain filler piece was glued on to the nose.
I then mounted the motor and used the prop adapter to "center" the nose ring and to clamp it into position. My nose rings are 2 lamination's. The aft layer is 1/16 ply and the forward one is 1/16 bass wood. This allows me to sand the nose ring for that perfect clearance to the spinner back plate. Bass wood sands much easier than birch ply! Of course I drew a circle slightly larger than 2 inches on the front face and a circle equal to the circle in the filler piece, before gluing it to the filler piece. Once dry I used my Dremel and a 1/8 router to do a rough cut out of the center of the nose ring. Then a sanding drum followed by hand sanding to finish it up.
Where balsa met the G-10 motor mount I used 15 minute epoxy and everywhere else Pica Gluit.
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"Mystery item for the day. What is it and what is it used for?"
My trained eye says its a popsicle stick used for shaping fillets.
. Bob
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"Mystery item for the day. What is it and what is it used for?"
My trained eye says its a popsicle stick used for shaping fillets.
. Bob
Bob,
Good guess! But that's not right. Something else. I'll reveal it in a day or so.
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Mystery item for the day. What is it and what is it used for?
My guess is a template for the safety plug.
James
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My guess is a template for the safety plug.
James
Another good guess. But that ain't it! :)
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Looking at the top photo in reply #60, are you building in a LOT of engine offset?
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Looking at the top photo in reply #60, are you building in a LOT of engine offset?
Wayne,
Just my usual amount. 2 degrees right thrust. It must be the angle of the camera that makes it look like a "lot". Then again what is the definition of a lot?
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I worked on my forms to mold the top fuselage blocks. The top will consist of 3 different molds. The most forward will be used for the hatch and has the forward most part begin to taper down to fair in the spinner. The middle block is basically straight across the top and the same width. And the aft piece is tapered both directions.
I used 1/4 floor underlayment plywood and used Gorilla glue to glue 2 pieces together. Very strong and stable. The plywood formers are made form 2.5mm plywood.
I cut out the 1/16 formers from balsa using 7# wood and used the ply formers as the template before I glued them to the forms. Once glued to the forms (medium CA), they were given a quick sanding and then the edges were blackened with a Sharpie magic marker as a sanding guide. Tomorrow I'll glue in the 2# blue foam.
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Then again what is the definition of a lot?
In this case, any. ;D
Just sort of kidding there Crist, the photo does make it look more extreme than 2 degrees. Personally, I build 'em zero-zero. I figure since we're flying on a tether that automatically gives us a fair amount of built in "offset". Everyone's got their way. D>K
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In this case, any. ;D
Just sort of kidding there Crist, the photo does make it look more extreme than 2 degrees. Personally, I build 'em zero-zero. I figure since we're flying on a tether that automatically gives us a fair amount of built in "offset". Everyone's got their way. D>K
10-4! Stay warm.
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Today I cut and glued the 2# blue foam on the forms. I used Gorilla glue to do this. After the glue dried, they were shaped with 120 grit sandpaper then followed up with 220 grit. As you see them they have 2 coats of WBP on them. I'll let them dry overnight and sand them again in the morning. Probably a few more coats after that.
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Wow, only 2 guesses so far on the mystery item!
The only hint I'll give is that it made from hard maple.
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Wow, only 2 guesses so far on the mystery item!
The only hint I'll give is that it made from hard maple.
I'll take another shot at it. But I need one of your turtledeck forms if I get it right, ok ?
Bob
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Wow, only 2 guesses so far on the mystery item!
The only hint I'll give is that it made from hard maple.
I'll take another shot at it. But I need one of your turtledeck forms if I get it right, ok ?
Bob
You got it Bob. Remember that my fuselage is about 3/8 wider than a gas L-40.
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That is the thing that goes where it's supposed to be to do what it's supposed to do... Whatever it goes and whatever it does.... Right??? LL~
That is one of the cleanest builds I ever saw... Dope!!!
Marcus
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That is the thing that goes where it's supposed to be to do what it's supposed to do... Whatever it goes and whatever it does.... Right??? LL~
That is one of the cleanest builds I ever saw... Dope!!!
Marcus
I like that answer, hard to argue.
James
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You got it Bob. Remember that my fuselage is about 3/8 wider than a gas L-40.
After spending many a hour analyzing your build drawing I've concluded it's not Part of the plane, it's an afterthought. Looking at the adjustable elevator I think I would want a tool for adjusting the position of the elevator pushrod. The maple jig would lend itself well and you would tack 1/64"ply to the tool for stepping the pushrod up or down until you are done trimming the elevator.
Rumplestiltskin is my name adjusting elevator is my game.
. Bob
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After spending many a hour analyzing your build drawing I've concluded it's not Part of the plane, it's an afterthought. Looking at the adjustable elevator I think I would want a tool for adjusting the position of the elevator pushrod. The maple jig would lend itself well and you would tack 1/64"ply to the tool for stepping the pushrod up or down until you are done trimming the elevator.
Rumplestiltskin is my name adjusting elevator is my game.
. Bob
Well Bob that is very clever, but still wrong. You are right it is not part of the plane itself. Tomorrow I'll reveal its identity.
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Today the forms got several coats of WBP with a light sanding between coats. Tomorrow I'll do some molding! Stay tuned.
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Yeah but I'd move the windscreen profile back a bit. Copying you're old one would be perfect IMO, right down to the canopy framework detail and overall paint scheme. y1
Hi Wayne & Chris,
Yea I agree with Wayne, the turtle deck is the way to go. But, perhaps moving the canopy forward would make it look little more of a jet look. Moving it to the rear is more WWII fighter look, but either has a great look so go get em.
Later,
Mikey
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Hi Wayne & Chris,
Yea I agree with Wayne, the turtle deck is the way to go. But, perhaps moving the canopy forward would make it look little more of a jet look. Moving it to the rear is more WWII fighter look, but either has a great look so go get em.
Later,
Mikey
Hi Mike!
Good to hear from ya. I really do agree with you guys on a turtle deck. But I have to pass this time around. I'm building this plane in memory of Allen and staying as close to the original design as possible.
Stay warm fellas.
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Time to reveal the mystery item.
It is a jig or form to mold a piece of 1/64 ply into a racetrack shape to line the tail wheel cut out in the bottom sheeting. The cut out is shown on the plans. Look carefully. I'll use some 1/2 brass tubing sharpened to cut 2 1/2 circles and the connect them with my #11 blade. Then the 1/64 ply will be trimmed to length and glued in the bottom sheeting. Then sanded flush. This will give me a clean, crisp edge!
I soak the ply in hot water for 1/2 hour then "stretch" it around the form and tape it into position. Then let dry while people try to guess what it is!
The last picture is from the prototype L-40 where I did not do this. Since then it is SOP. The one before that is from another model where the bottom sheeting is molded.
Thanks for all you guessed. I thought I'd break up the monotony of "then I glued this, and sanded that"......
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Whoah. I would NEVER have guessed that. ;D
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Arrgh!!! I saw that shape at the tailwheel but said nah, he wouldn't plug the access with maple, too heavy he's trying to build light. Never thought it would be a mold. Get back to the build log.
Bob
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OK Bob. Here are top blocks that are molded. The front is the hatch, then the middle, then the aft piece. The hatch and the middle were molded using 1/16 7.6# balsa and the aft piece was molded using 6.7# balsa.
After they came off the forms the formers were glued in using thin CA. The front and aft of the hatch are laminated with 1/32 Basswood to maintain a nice crisp edge while the bottom is 1/32 ply for strength. The forward former is also laminated with 1/32 basswood. These are the hatch parting surfaces and I want then nice.
The forward part of the hatch is held in position by a 1/16 ply 1/4 wide tongue.
Weights are the hatch is 11 grams, middle is 5 grams and the aft is 6 grams. I made the hatch pretty beefy. I could cut out some of the 1/32 ply bottom.
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That is awesome.
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Thanks Doc.
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See, I was right!!!
Cool build...
Marcus
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How's the new LOG coming?
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How's the new LOG coming?
Trying to decide on what colors to use for the finish. Getting ready to Monokote the wing and stab.
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Trying to decide on what colors to use for the finish.
LL~ LL~ LL~ LL~ LL~
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Lay a couple pointers on monokoting.I have a tough time around the canopy.
Bob
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Been lurking in the background but paying attention. There is NOTHING like a Crist Righotti build thread for getting schooled on building light and accurate - another BRAVO my friend!
As for your agonizing over your colors, I second the wwwarbird:
LL~ LL~ LL~ LL~ LL~ 8)
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What's up here Crist?
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What's up here Crist?
Got a bit sidetracked with another project. I'm getting back to it very soon. Stay tuned!
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You wishing you still had a snow blower ????
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You wishing you still had a snow blower ????
Naw, I just waited a couple of hours! Today was back to short sleeves!
I have the bench all cleared off so I'll start back on the L-40 this weekend.
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Spectacular build! ;D
I can't wait to see the covering tricks you use. ;)
Regards,
Chris
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Chris. Thank you.
I really don't have any tricks for Monokoting. I will share what I do though. Traveling this week and next, then onto finishing the L-40.
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Built the flaps today. I used 9# balsa and they are built just like the elevators. I used medium CA to laminate the balsa pieces. Then thin CA to glue in the ribs followed by a second gluing with medium CA. Very strong flaps!
The left flap weighs 25 grams and the right flap 27 grams.
On to the detailed sanding then Monokote!
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I finished the detailed sanding and had to use filler on a few spots. I use Aero-Poxy Lite. Tomorrow the filler will be sanded out and the Monokote will begin.
Here are the weights of the pieces that will be covered in Monokote:
Wing - 288 grams
Stab - 44 grams
Left Elevator - 13 grams
Right Elevator - 15 grams
Left Flap - 25 grams
Right Flap - 27 grams.
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Looks like she is going to be a light weight.
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Looks like she is going to be a light weight.
Doc, it looks like I'm going to be 50 - 52 ounces all fueled up!
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I got the stab, elevators and flaps covered today. Standard Monokote procedures. I do use a separate piece of Monokote to cover the root end of the flaps and elevators. This piece is then trimmed to about 1/16. I thought that I'd give some detail on how I cover the hinge pockets.
1- I cover the side of a flap or elevator and wrap the Monokote around just past the center of the piece.
2- I then trim off the excess Monokote.
3- I then take my scapel and cut the sides of each pocket.
4- Then I take my sealing iron and press the Monokote into the "bottom" of the hinge pocket. It doesn't have to be completely stuck down, just close.
5- Then I trim away the Monokote to expose the hinge slot.
6- Then with my trim tool, I seal down the Monokote to the "bottom" of the hinge pocket.
7- Then I rotate the trim tool 90 degrees and press it up against the side of the hinge pocket to seal the sides. I do this on both sides of the hinge pocket.
8- Cover the other side and repeat steps 2 thru 7.
When completely done, I'll touch up the sides of each hinge pocket with either Lustercoat or Nelson paints. The Nelson paint is an exact match of the Monokote colors.
Tomorrow the wing and I start the trim colors.
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Thanks, Crist for taking pictures of the covering hinge detail.
While I'm known to be a detail-oriented builder in the RC sailplane world, I rarely have to deal with pinned hinges, which are the norm here.
Please continue with your pics when you have time. I know that it only slows a build down (I've documented LOTS for sailplane builds on RCGroups), but it is very helpful for me at least, if not others.
Thanks!
Looks amazing, BTW! #^
Regards,
Chris
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Well the white Monokote is done. Now on to the trim colors of red and blue. Pictures to follow.
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I put on the red and blue stripes. I use the Windex method. Very basic techniques used. The sealing iron was set about 1/2 way, Windex applied to the backside of the Monokote, it was then positioned on the wing/flap/stab/elevator and "tacked" on one end. It was then stretched and "tacked" to the other end. Then it was rubbed down with a soft rag to expell all of the Windex. Left to dry overnight, then gone over with the sealing iron set to about 1/3.
I then added the hinges. I hinge the control surface first (flaps and elevators). I use Klett hinges and 1/32 music wire to position them fore and aft. I cut the music wire a little longer than the surface and put a 90 degree bend on one end to help give me a grip when I remove the wire. I then grind a point on the other to help "find the hole" of the hinge barrel. I then place the hinges on the music wire. Note that the hinges all have the end barrel toward the tip. This will help when attaching the flap/elevator to the wing/stab by allowing the flap/elevator to be moved up/down/in/out to help guide the .025 music wire hinge pin. More on that when the time comes. Just remember to have the end barrel toward the tip. I use Pacer 560 canopy glue to glue in the hinges. I put it in one of those squeeze bottles with a needle on it that Tom Morris sells. I then squeeze some glue down into the hinge slot. I then place the hinges into the slot and wipe up and ooze out with a rag and water. I then use the straight edge of my workbench to press the hinges into the slot till the 1/32 music wire just touches the LE of the flap/elevator. Don't push it down hard at all. If you go too hard the music wire will not be straight thus the hinge barrels will not be straight either. Don't worry about the 1/32 gap left because of the music wire. Later we are going to seal all of the control surfaces with sealing tape so the gap won't matter. When dry overnight, remove the wire and install the wing/stab hinges to the flap/elevator using the 1/32 music wire and repeat gluing the hinges to the wing/stab. Again don't push too hard. You shouldn't have to if you built nice straight TE and LE. When dry, remove the 1/32 music wire. I'll go over the actual method I use to install the flap/elevator later.
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I did the wire through the hinge pins on one plane. Did not make hinge pockets either. When the surfaces were finally glued the wire almost sealed the joint. Most of my Monokote coverings seal the hinge joints anyway.
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Now to attach the control surface to either the wing or stab. Here are pics of the elevators to stab.
I first install the hinges in position with the 1/32 music wire. You'll note that they have been trimmed down in length because my TE chord is only 1/2 inch with a CF doubler on the inside.
I did this for both elevators and then glued the hinges in like on the elevators. A quick wipe of the excess glue ooze out and I'm done. Note that I'm using the elevator horn to get the elevators properly spaced.
The flaps will done in a similar manner.
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OK, the hinges are all installed. I thought I'd show you how I retain the .025 music wire hinge pins.
Near the tip of the wing or stab and just below center, I install a SIG 1/32 eyelet. I use a T pin to locate the position and then drill a 1/16 hole about 1/4 inch deep. I insert the eyelet about half way and then I put on a small drop of thin CA glue. I immediately push in the eyelet even with the TE. The hinge pin is them measured for length and the cut off. The hinge pin should not be long enough to touch the control horn. On one end I put a 90 degree bend no more than 1/8 from the end. I sharpen the other end slightly to aid going into the hinge barrels. I then attach the control surface by inserting the hinge pin from the tip toward the center. I use a small pair of needle nose pliers to grab the 90 degree bend and insert it into the eyelet. The reason for locating the eyelet slightly below center is two-fold. 1) To make it easier to install and remove the hinge pin. 2) It provides some tension to the wire to help keep it in place.
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Hi Christ,
thanks for the information on your building techniques. I do have one question though: when you have finished doing the hinges and before you connect up to the bell cranks, do your elevators and flaps drop down under their own weight? I ask as I am trying to work out what level of resistance I should end up with.
Thanks in advance,
Jonathan
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Hi Christ,
thanks for the information on your building techniques. I do have one question though: when you have finished doing the hinges and before you connect up to the bell cranks, do your elevators and flaps drop down under their own weight? I ask as I am trying to work out what level of resistance I should end up with.
Thanks in advance,
Jonathan
Jonathan,
Thank you. Yes, the control surfaces flop down very easily on their own weight. Some resistance will be added when I seal the hinge gaps. More on that later.
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Thanks Chirst, I am not sure if I am now depressed how much I could improve or happy that I know have a way to improve!! ;D
Jonathan
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OK, the hinges are all installed. I thought I'd show you how I retain the .025 music wire hinge pins.
Near the tip of the wing or stab and just below center, I install a SIG 1/32 eyelet. I use a T pin to locate the position and then drill a 1/16 hole about 1/4 inch deep. I insert the eyelet about half way and then I put on a small drop of thin CA glue. I immediately push in the eyelet even with the TE. The hinge pin is them measured for length and the cut off. The hinge pin should not be long enough to touch the control horn. On one end I put a 90 degree bend no more than 1/8 from the end. I sharpen the other end slightly to aid going into the hinge barrels. I then attach the control surface by inserting the hinge pin from the tip toward the center. I use a small pair of needle nose pliers to grab the 90 degree bend and insert it into the eyelet. The reason for locating the eyelet slightly below center is two-fold. 1) To make it easier to install and remove the hinge pin. 2) It provides some tension to the wire to help keep it in place.
I use a loop of Spiderwire or other thin monofilament to pull the hinge pin from the eyelet when I take a flap off. When I tried to grab the pin with pliers without first pulling it out of the hole, I either dented the airplane with the pliers or poked another hole when the pin slipped out of the pliers and snapped back.
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Thanks for the pictures as they answer a lot of questions.
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I use a loop of Spiderwire or other thin monofilament to pull the hinge pin from the eyelet when I take a flap off. When I tried to grab the pin with pliers without first pulling it out of the hole, I either dented the airplane with the pliers or poked another hole when the pin slipped out of the pliers and snapped back.
Great idea Howard. Been there, done that!
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Thanks for the pictures as they answer a lot of questions.
You are welcome, Doc.
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Glued the wing in today!
First thing I did was insert the flap horn into the fuselage then slide the wing into position. Then I install the flaps. Then I used some 1/8 thick medium balsa to shim the flaps away from the fuselage sides. These shims fit fairly snug. The TE is now properly positioned and now to line up the LE. I use a tape measure and use a pin at the very tail. I then move the wing LE back and forth till the distance is equal on both sides. Of course I take into account the 1/2 inch offset of the wing. I then draw a line with a thin line "Sharpie" on the outside of the fuselage on both sides top and bottom. These lines will be used when I notch the Monokote. I remove the flaps and wing then I put marks every 3/4 inch to locate the apex of each notch for the Monokote. I then used my scalpel to put notches in the Monokote. When done I wipe the marker off with some rubbing alcohol. I then seal the Monokote down with my sealing iron. BTW, Monokote sticks really good to the doped silkspan circles I added earlier.
I then reassemble the wing/flaps/shims and locate the LE with the tape measure method again. I also make sure the wing is level too! When I'm satisfied, I tack glue the wing with thin CA. 1 last chance to check everything! Then I use medium CA along the inside joint.
Then I installed the 1/16 ply bell crank post reinforcement with medium CA.
I reinforce the whole thing with 3 ounce fiberglass cloth. I have the FG go up the sides, the LE bulkhead, and the other bulkheads about 3/8 inch. Once cut to size I use a light coat of #77 contact cement. I then locate the FG onto the wing and press it down into position. The contact glue allows it to be positioned before I add the epoxy glue. I use MGS 285 epoxy and using an acid brush I fill the weave with epoxy. I add an extra amount along the the joint where the wing and fuselage meet to force some epoxy into the joint. Then I use a square of toilet paper to blot the excess epoxy off. If you see any shiny spots, that a "puddle" and it needs blotted. When done I added an extra strip on each side over the flap horn tubes at the TE.
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This evening I installed the push rods. I first install the flap push rod and adjust the length so that I get equal throw in both directions. If you remember that I drilled a 1/16 hole along the center line of the wing the same distance of my flap horn. This is what I determine to be neutral. I then adjust the push rod to get the equal throw that I'm looking for.
I then installed the elevator push rod and adjusted the length for neutral elevator. You sharp eyed people will notice that my elevator ball link is not a standard link. The barrel is longer. This is what I use when I find that my push rod seems just a little short. I like the majority of the push rod threads to be engaged into the plastic barrel when neutral. On the initial set up, I felt that a little too much thread was showing so I used my "long" barrel version of ball link. Now the threads are a lot further engaged into the ball links.
On the elevator ball link I use a slider elevator horn. This allows me to adjust the flap/elevator ratio when trimming the airplane. Notice that I use a washer as a "keeper", the ball link, another washer, the elevator horn, a washer, and finally a reduced sized MS lock nut. You must use a washer on each side of the slider type elevator horn. This prevents the slotted portion of the horn from spreading out and a possible control system failure.
Tomorrow the fuselage gets closed up and final sanding and tweaks here and there. I'll be starting the "finish" real soon.
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Today I did some minor work to prep the fuselage for the bottom sheeting and top blocks. I cut out a hatch on the bottom for Igor's active timer, terminated the lead outs, and leveled the stabilizer platform. I then used Pica Gluit to glue the top and bottom blocks on. I first wet the parting surfaces with water (thank you Bob Hunt). This helps get a nice tight joint. I used masking tape to hold everything in place. I did not glue in the stab yet. I glue it in after I get the fuselage covered with 2/10 CF and a few coats of dope. Then I'll glue in the stab and then I'll add the fillets. I do it this way to prevent a misalignment between the wing and stab in case the fuselage moves with the doping and such. One the CF is doped down, the fuselage is stable.
I included a picture of the tail wheel mount and bottom sheet recess. Remember the "mystery" part?
Some sanding and such and I have to make up the landing gear covers next. Then on to the finish!
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I started on the finish today. I'm using all SIG dope for the fuselage, fin, rudder, and hatches. Usually I use SIG Nitrate dope to adhere the CF to the balsa through the filler coats. This time it'll be all Butyrate from the bare balsa.
I started with 2 coats of SIG Supercoat (high shrink) clear thinned 75/25 dope/thinner. I sanded lightly after each coat. I then added the 2/10 CF using 25/75 dope/thinner. The CF has a soft velvety feel to it right now. I'll weigh it tomorrow.
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Waiting for the second coat of 50/50 clear to dry then some light sanding and then I'll weigh it to see what the finish weighs so far.
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OK, the finish so far has 2 coats of 75/25 dope/thinner, CF applied with 1 coat of 75/25 dope/thinner, and 2 coats of 50/50 dope/thinner then sanded lightly. Total so far is just 13 grams.
Another coat of 50/50 clear tonight, then another light sanding and on to gluing in the stab and fin. Then the fillets.
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Oh I thought you were using Monokote on the fuse as well
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The wing, stab, and fin fillets are done. Just waiting for the canopy to dry then I'll add that fillet. Then it's all the finish from then on. No more building. Pics tomorrow!
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The fillets added a total of 5 grams to the airframe! Here is a quick run down on how I do fillets. You can do them any way you want to. Bob Hunt has a good series on doing fillets too.
I use Aero-Poxy Light because I feel it gives the wing/stab to fuselage joints strength.
I use a 3/8 and 1/4 ball bearing epoxied to 1/4 hardwood dowels to form the fillet. These are used because they can be held at any angle to the joint and still provide a constant radius fillet. Some rubbing alcohol, single edged razor blade, craft sticks, and paper towels.
I use my gram scale with a 10X multiplier so I can measure to 1/10 gram when weighing the amounts of resin and hardener to be mixed. These are mixed 2 parts resin to 1 part hardener by weight. One side of the wing, top and bottom, takes about 5 grams of resin and 2.5 grams of hardener. I mix these in one of the small plastic mixing cups. I mix them very well!
Then I take the fillet material and trowel into the joint using a slightly sharpened craft stick for the stab. No need to sharpen a stick for the wing. I show the stab/fuselage joint in the pics.
I then take some alcohol and sprinkle it on to the fillet.
I take the 1/4 ball tool and press it into the joint and follow it around the entire joint. Go slow and wipe off the excess from the ball bearing often.
Then I use the single edged razor blade and scrape the excess away from the fillet and wipe it on a paper towel soaked with alcohol. The ball bearing tool leaves a small width where you can get close to the fillet to scrape safely.
Then I take a paper towel and fold it into 1/4 and soak one edge with alcohol. I then wipe the Monokote and fuselage to clean off the residue from scraping.
I let this sit for about 45 to 60 minutes then I take some alcohol and again sprinkle it onto the fillet. Then very gently rub my finger onto the fillet to really smooth it out. Then a final wiping with a alcohol soaked paper towel and I'm done.
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I couldn't resist!
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Love the ball bearing tool. Great idea, thank you!
R,
Chris
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Today I sanded the coat of clear and then used NAPA DC540 Primer on the plane. I loaded it on and then about 1 hour later I sanded most of it off. I started off with 320 dry but switched to wet and it went well after that. Before I started sanding, I used some glazing putty to take care of the most glaring areas. Then I wiped it down using some rubbing alcohol and will now use my sprayer from now on. Tomorrow it will get 2 more coats of clear. BTW, I'm done using the high shrink Super-Coat and will now use low shrink Lite-Coat from here on out.
After the clear and more sanding, I'll shoot my gray blocker coat. Then I know how good the finish really is.
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That's one fine looking moscheen. What did you decide on for a power plant?
Bob
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That's one fine looking moscheen. What did you decide on for a power plant?
Bob
LA 46, what else!
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Really a Cobra 2826/12 750Kv motor.
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After a few coats of clear wet sanded with 600 grit, I sprayed on my blocking coat of gray. White SIG dope with a little Jet Black added. Total weight gain is 10 grams.
I'll do the auto body glaze thing, then touch up the gray, then on to the white.
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The glazing putty has been applied! More wet sanding ahead. In reality, the glazing putty wet sands very easily and feathers out beautifully.
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The glazing putty has been sanded and the plane cleaned off.
It'll be awhile before I can go much further. My vent system needs a bit of revamping and the parts won't be here till later this week. Then I'll touch up the gray then on to the white.
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The glazing putty has been sanded and the plan cleaned off.
It'll be awhile before I can go much further. My vent system needs a bit of revamping and the parts won't be here till later this week. Then I'll touch up the gray then on to the white.
That muffler slot seems really far back for an LA.46. ;D
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That muffler slot seems really far back for an LA.46. ;D
Wayne, that's the primer hole for the tuned pipe! ;)
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Crist, you mean the electron exhaust port??!!
Regards,
Chris
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Crist, you mean the electron exhaust port??!!
Regards,
Chris
Exactly!
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I got the vent parts in today. Tomorrow, Wednesday I shoot the white!
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I shot the white today. The humidity got around 50% or so and I added a little retarder. 13 grams added for the white. 40 grams so far for the finish. Tomorrow I'll sand the white and add a coat of clear to seal it. Then on to the trim colors.
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Well I had to shoot the white again in a few places. Seems that I didn't get enough paint down and when sanding, I sanded through the white. So I shot the touch up white today. Tomorrow I'll try again whit the clear seal coat.
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I did the clear seal coat over the white today. It laid down nice and flat. 3 grams added and still gassing off. 48 grams so for the finish. Tomorrow the red trim gets painted.
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The red trim has been sprayed on. It is SIG Fokker Red. A real nice deep rich color red. Almost a blood red. 4 grams added and still gassing off. Total finish so far is 53 grams.
Tomorrow I'll sand off the flash then on to the blue. Not sure if I'll get that sprayed or not. I have some things to do around the yard.
I like this phase of construction/finishing. The plane is now taking on it's own personality with each trim color added. A lot of masking and not a lot of dope being added, but it really makes a difference.
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I got the blue sprayed on today. I use 3 parts of Dark Blue and 1 part of Miami Blue. It will match the Sapphire Blue Monokote pretty close. Again all SIG dope.
Tomorrow it'll get the flash sanded off and the canopy detailing should get done. Then on to the clear coats....whew! BTW, the blue trim added 2 grams. Total finish so far is 55 grams.
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Crist,
It's looking good. You're going to have to make a trip north with it this summer :)
James
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Crist,
It's looking good. You're going to have to make a trip north with it this summer :)
James
I'm planning on it!
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I did the canopy today along with some clear coating. Pics to follow later tonight.
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Here are a few pictures. I need to add the black letters and AMA numbers to the wing and a few other details. I added 13 grams of clear for a total finish weight of 68 grams. I'll let it rest for a few days then get on with installing the motor and such.
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Canopy painted on the inside??
R,
Chris
PS. Looking good!
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Canopy painted on the inside??
R,
Chris
PS. Looking good!
No, it's painted on the outside with the rest of the airframe.
Thanks for the kind words.
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I love it. y1
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Thanks Doc.
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Wow, CLEAN!!!!
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Thanks Wade. I have to touch up the Monokote and clean it up with acetone then wax it. I have to get those numbers on the wings, then it will look a lot better. Stay tuned!
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After sitting for a week to let the dope somewhat harden, I started installing the electric stuff. I have the motor, Jeti Spin 44 ESC, Igor's active timer, and Howard's BICAS installed. Still some more details to do. I use 3M Dual Lock SJ4570 to hold the ESC, BICAS board and LED's, and Igor's board in place. I love the stuff!
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Very clean installation, nicely done. y1
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I finished putting in the gear and all and did a preliminary CG and weight check. The CG came out on the forward side, which is good, but the weight of the model will end up being 57 ounces...ouch! I have no idea where the extra weight came from. The wing ended up being 2 ounces more and would have put the model at 52 ounces, just like all the other electric ones before it. The weights of everything else was pretty much on target. I'll have to check my notes and weight and balance sheet. I'm a bit bummed right now.
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Any finished pics Crist?
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Wayne,
I'm planning on going out tomorrow for first flights. I want to get some outside by the circle. The batteries are charging as I type. It'll be a bit windier than I'd like, but it looks like my only chance for a week!
Pics and report tomorrow evening, I promise.
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Good luck for a "boring" maiden.
R,
Chris
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What was the final weight?
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Well the first flights are done. It was a bit breezy at Hobby Park in Dallas today. The tough part about it was the 8 to 10mph breeze was coming off the treeline by the railroad tracks. Made for a very bumpy choppy flights. I put in 5 flights and got the lap speed around 5.2 second laps, the wings look pretty level, the handle neutral has been adjusted, and the inside/outside turn rate worked on to get it close. The tip weight was a little heavy and next time out I'll pull out a 1/4 ounce. That was about all I could comfortably do with those conditions. It looks like another week of windy/rainy weather.
Here are some pictures of it. I might spend some time tarting it up, not sure though. Oh, BTW Tom Niebuhr cut the vinyl letters for me. They are great!
The final weight so far is 56.7 ounces, all fueled and ready to go.
I do think this plane will be a good flying plane. The turn is very smooth and I just need to put some flights on it to get used to it too!
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Looks like a winner. Don't be too rough on those Texas lads. LL~ LL~
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Looks like a winner. Don't be too rough on those Texas lads. LL~ LL~
Thanks Doc. I'll go easy on 'em!
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Well done Crist!! Looks like a winner to me and you have produced a wonderful build log!!! y1
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Thanks John! Say hi to the guys in Iowa for me.
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The L-40 met its demise this morning. 72 degrees, slight breeze from the South, cloudless blue sky. The 2nd flight on the 2nd loop of the Clover I got a line clip snag! Went straight in at about 90 degrees from about 10 feet. The front end disintegrated.
The small pieces of a good portion of the nose just drifted off the circle in the slight breeze. The battery and motor are gone.
The pictures tell the aftermath.
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Bummer!!!!!!!
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That sucks. Are you going to fix the nose? Or is it on to the next ship.
Bob
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Christ,
Hate to see that brother. Is it repairable?
James
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Bob and James,
It probably can be repaired. However, seeing it was almost 58 ounces, 6 to 8 ounces overweight, I'm not going to bother.
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My condolences Crist! Gee if I was any where near you I would take it off your hands and build a new nose!
After all that work and struggling with the cooling, it "has to make you very sad!
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Thanks John. It's time to move on to another airplane.
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man, that stinks...
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That is sad to see Crist. But now you can incorporate all you have learned on the new one.
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Golly!
bummer to see ...
Dean P.
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Sad to see.
Happy only the model was harmed.
I agree with John, you can apply all you learned to the next latest and greatest build.
R,
Chris
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Sad to see.
Happy only the model was harmed.
I agree with John, you can apply all you learned to the next latest and greatest build.
R,
Chris
Yup, that's for sure.
Thanks John and Dean.
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Bob and James,
It probably can be repaired. However, seeing it was almost 58 ounces, 6 to 8 ounces overweight, I'm not going to bother.
Crist
You are very methodical about tracking your build weights. Were you able to determine WHERE the unexpected weight came from?
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Crist
You are very methodical about tracking your build weights. Were you able to determine WHERE the unexpected weight came from?
Dennis,
No, I am stumped. All the sub assemblies were on target for a 52 oz airplane. Very similar to the other 3 same size electric airplanes that I built. The weight must have crept in during final assembly. It wasn't the finish either. That was spot on target too. I can see an ounce or 2 that I would miss by, but almost 6 ounces, that hurt. I'll track the next one closely too and we'll all see how that turns out.
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Crist,
Sorry see that you lost the airplane. Well on to the next one. Let me know when you are ready for paint masks.
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Crist,
I was in and out of this Thread taking a peek now and again.
I thought you did a realy fine job with this model. I especially liked the Thunderbird stunt team look on the nose and the motor mount. Reminded me of mine mount.
Anyway, I redid a nose and turned a IC model into an "E" model quit easily.
Be a shame not to fix this fine model.
I believe it's worth fixing and I'll bet you could get it back in the air in no time at all.
Good luck with whatever you decide.
Charles
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Thanks Tom and Charles.