Author Topic: Legacy 40 - Electric A build Log (Read 65766 times)

Dennis Adamisin · « **Reply #100 on:** February 12, 2015, 06:36:25 PM »

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:

wwwarbird · « **Reply #101 on:** February 28, 2015, 05:50:45 PM »

What's up here Crist?

Crist Rigotti · « **Reply #102 on:** February 28, 2015, 07:10:41 PM »

Quote from: wwwarbird on February 28, 2015, 05:50:45 PM

What's up here Crist?

Got a bit sidetracked with another project. I'm getting back to it very soon. Stay tuned!

Leester · « **Reply #103 on:** March 06, 2015, 01:33:49 PM »

You wishing you still had a snow blower

?

Crist Rigotti · « **Reply #104 on:** March 06, 2015, 10:12:58 PM »

Quote from: Leester on March 06, 2015, 01:33:49 PM

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.

Target · « **Reply #105 on:** March 10, 2015, 10:42:23 PM »

Spectacular build!

I can't wait to see the covering tricks you use.

Regards,
Chris

Crist Rigotti · « **Reply #106 on:** March 12, 2015, 07:02:26 AM »

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.

Crist Rigotti · « **Reply #107 on:** March 22, 2015, 08:16:30 PM »

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!

Crist Rigotti · « **Reply #108 on:** March 23, 2015, 07:01:51 PM »

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.

john e. holliday · « **Reply #109 on:** March 24, 2015, 01:47:43 PM »

Looks like she is going to be a light weight.

Crist Rigotti · « **Reply #110 on:** March 24, 2015, 03:30:10 PM »

Quote from: john e. holliday on March 24, 2015, 01:47:43 PM

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!

Crist Rigotti · « **Reply #111 on:** March 24, 2015, 08:31:51 PM »

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.

Target · « **Reply #112 on:** March 25, 2015, 10:29:43 AM »

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

Crist Rigotti · « **Reply #113 on:** March 26, 2015, 05:23:10 PM »

Well the white Monokote is done. Now on to the trim colors of red and blue. Pictures to follow.

Crist Rigotti · « **Reply #114 on:** March 28, 2015, 04:19:49 PM »

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.

john e. holliday · « **Reply #115 on:** March 29, 2015, 05:05:27 PM »

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.

Crist Rigotti · « **Reply #116 on:** March 29, 2015, 11:01:12 PM »

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.

Crist Rigotti · « **Reply #117 on:** April 01, 2015, 05:26:18 AM »

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.

Jonathan Chivers · « **Reply #118 on:** April 01, 2015, 06:23:34 AM »

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

Crist Rigotti · « **Reply #119 on:** April 01, 2015, 07:05:43 AM »

Quote from: Jonathan Chivers on April 01, 2015, 06:23:34 AM

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.

Jonathan Chivers · « **Reply #120 on:** April 01, 2015, 07:25:47 AM »

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!!

Jonathan

Howard Rush · « **Reply #121 on:** April 01, 2015, 01:38:20 PM »

Quote from: Crist Rigotti on April 01, 2015, 05:26:18 AM

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.

john e. holliday · « **Reply #122 on:** April 01, 2015, 01:49:20 PM »

Thanks for the pictures as they answer a lot of questions.

Crist Rigotti · « **Reply #123 on:** April 01, 2015, 01:56:10 PM »

Quote from: Howard Rush on April 01, 2015, 01:38:20 PM

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!

Crist Rigotti · « **Reply #124 on:** April 01, 2015, 01:56:43 PM »

Quote from: john e. holliday on April 01, 2015, 01:49:20 PM

Thanks for the pictures as they answer a lot of questions.

You are welcome, Doc.

Crist Rigotti · « **Reply #125 on:** April 02, 2015, 04:27:43 PM »

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.

Crist Rigotti · « **Reply #126 on:** April 02, 2015, 10:10:06 PM »

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.

Crist Rigotti · « **Reply #127 on:** April 03, 2015, 05:53:52 PM »

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!

Crist Rigotti · « **Reply #128 on:** April 05, 2015, 08:47:28 PM »

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.

Crist Rigotti · « **Reply #129 on:** April 06, 2015, 04:27:25 PM »

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.

Crist Rigotti · « **Reply #130 on:** April 06, 2015, 05:18:34 PM »

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.

Dwayne · « **Reply #131 on:** April 06, 2015, 08:50:38 PM »

Oh I thought you were using Monokote on the fuse as well

Crist Rigotti · « **Reply #132 on:** April 08, 2015, 11:17:44 PM »

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!

Crist Rigotti · « **Reply #133 on:** April 09, 2015, 10:08:55 AM »

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.

Crist Rigotti · « **Reply #134 on:** April 09, 2015, 10:35:59 AM »

I couldn't resist!

Target · « **Reply #135 on:** April 09, 2015, 11:24:18 AM »

Love the ball bearing tool. Great idea, thank you!

R,
Chris

Crist Rigotti · « **Reply #136 on:** April 10, 2015, 07:15:06 PM »

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.

Bob Hudak · « **Reply #137 on:** April 11, 2015, 07:21:06 AM »

That's one fine looking moscheen. What did you decide on for a power plant?
Bob

Crist Rigotti · « **Reply #138 on:** April 11, 2015, 07:42:08 AM »

Quote from: Bob Hudak on April 11, 2015, 07:21:06 AM

That's one fine looking moscheen. What did you decide on for a power plant?
Bob

LA 46, what else!

Crist Rigotti · « **Reply #139 on:** April 11, 2015, 07:43:47 AM »

Really a Cobra 2826/12 750Kv motor.

Crist Rigotti · « **Reply #140 on:** April 12, 2015, 07:26:50 PM »

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.

Crist Rigotti · « **Reply #141 on:** April 12, 2015, 08:13:27 PM »

The glazing putty has been applied! More wet sanding ahead. In reality, the glazing putty wet sands very easily and feathers out beautifully.

Crist Rigotti · « **Reply #142 on:** April 13, 2015, 07:33:03 PM »

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.

wwwarbird · « **Reply #143 on:** April 13, 2015, 08:02:26 PM »

Quote from: Crist Rigotti on April 13, 2015, 07:33:03 PM

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.

Crist Rigotti · « **Reply #144 on:** April 14, 2015, 07:44:42 AM »

Quote from: wwwarbird on April 13, 2015, 08:02:26 PM

That muffler slot seems really far back for an LA.46.

Wayne, that's the primer hole for the tuned pipe!

Target · « **Reply #145 on:** April 14, 2015, 03:43:18 PM »

Crist, you mean the electron exhaust port??!!

Regards,
Chris

Crist Rigotti · « **Reply #146 on:** April 14, 2015, 05:06:46 PM »

Quote from: Chris Behm on April 14, 2015, 03:43:18 PM

Crist, you mean the electron exhaust port??!!

Regards,
Chris

Exactly!

Crist Rigotti · « **Reply #147 on:** April 14, 2015, 08:36:46 PM »

I got the vent parts in today. Tomorrow, Wednesday I shoot the white!

Crist Rigotti · « **Reply #148 on:** April 15, 2015, 06:29:43 PM »

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.

Crist Rigotti · « **Reply #149 on:** April 16, 2015, 04:17:34 PM »

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.

Author Topic: Legacy 40 - Electric A build Log (Read 65766 times)

Dwayne