Author Topic: Fancherized Twister Build Chronicle for Jr. NATs (Read 10049 times)

Brendan Eberenz · « **on:** January 27, 2022, 09:57:22 PM »

My son, Angstrom (age 11), and I (Brendan) are going to build a Fancherized Twister. I've built multiple foam wing trainer planes and one kit (a Lightning Streak). I've also done a lot of repairs on planes we have crashed as we try to get up to speed on Stunt. I'm a novice builder, at best, but it's time to get my hands dirty and see if we can crank out a Fancherized Twister. Angstrom has entered the Beginner competition at the NATs the last couple of years and we are hopeful that this plane can be his entry for the Junior event. That event has a BOM component, so this is essentially Angstrom's build. The other thing to keep in mind is that we want to keep the plane within expectations for a Nostalgia entry. Angstrom has some other planes he will use for other events, but we would like to have this Twister available for events (after NATs) where Nostalgia is an option.

I have read some of the Fancherized building threads and have some sense of what to do, but we don't have a local veteran builder looking over our shoulder. That's why I want to start this thread chronicling our build and giving people an opportunity to weigh in (hopefully before we screw something up). I will provide as many pictures as I can and try to keep people updated as we progress or gameplan. I also regularly attend the Monday/Friday online hangout sessions. Angstrom and I plan to try to attend the Friday calls for on the spot help and advice from those in attendance.

Let me update you on where we are going into the build tomorrow night...

I have attached a picture of what we got lined up. We have a Brodak Wing jig. It is short for the whole Twister wing, so we are prepared to build a half at a time and then jig the middles halves together to finalize it. Angstrom spent tonight putting the spars together and lightly sanding them to equal size and shape. He also used a drill press to create 5/16 holes for the jig rods. Should be ready to mount on the rod and glue tommorrow night. In the picture I also include some pieces from a wooden jig assembly I recently bought. Without knowing for sure, I assume the slotted rectangles go on the bottom of the ribs to keep them square with the table as you go to glue. Let me know if there are other ways the laser cut jig assembly pieces might help me. Finally, in case you couldn't tell, I have a piece of glass from an old coffee table over the plans. Figure that will keep the plans nice but visable. For anyone on the call tomorrow night, feel free to remind me to rub down the rods with soap to prevent accidentally glueing the rods to the ribs.

To be continued...

john e. holliday · « **Reply #1 on:** January 27, 2022, 10:04:52 PM »

Tell him and yourself to take it slow and double check everything. I still have one hanging in the shop that was built when Ted first did the article. Flies much better than I do. LA 40 for power.

Craig Beswick · « **Reply #2 on:** January 27, 2022, 10:12:53 PM »

If you are going to build on that glass please check that it is flat. It doesn't have to be level, better if it is but doesn't have to be. But it does need to be flat, left to right, front to back and diagonal.

You need a good quality straight edge.

Great project, good for you dad!!!

Best of luck
Craig

Ken Culbertson · « **Reply #3 on:** January 27, 2022, 11:52:16 PM »

After a 30+ year layoff, I returned to Stunt. On the recommendation of many here I built a Fancherized Twister as a practice plane. Flew it about 5-10 flights a week for 2 years while I built my PA and Classic. You cannot find a better work horse stunter. Build it straight with a stiff fuselage and you can't go wrong. What is so nice is that the kit is so easy to modify into whatever profile shape you want and it still has those great flight characteristics. Take a lot of pictures, there are a lot of Twister alumni here eager to help. You didn't mention power. It is a great fit for electric and not too small for something like an LA46. Please don't under power it.

Ken

Brendan Eberenz · « **Reply #4 on:** January 28, 2022, 08:24:03 AM »

Quote from: Craig Beswick on January 27, 2022, 10:12:53 PM

If you are going to build on that glass please check that it is flat. It doesn't have to be level, better if it is but doesn't have to be. But it does need to be flat, left to right, front to back and diagonal.

I will take a look. I assumed "flat," but it is worth checking for reassurance.

Brendan Eberenz · « **Reply #5 on:** January 28, 2022, 08:27:12 AM »

It will be an electric setup. I will share more about that later after I run a few tests on a motor/battery combo I am using with another Twister we were gifted. Just trying to ensure we hit a system with 5.5 minutes flights.

Dan Berry · « **Reply #6 on:** January 28, 2022, 08:31:19 AM »

Quote from: Brendan Eberenz on January 28, 2022, 08:24:03 AM

I will take a look. I assumed "flat," but it is worth checking for reassurance.

Check for flat with string pulled across the corners diagonally.

Dan McEntee · « **Reply #7 on:** January 28, 2022, 09:56:14 AM »

Quote from: Dan Berry on January 28, 2022, 08:31:19 AM

Check for flat with string pulled across the corners diagonally.

Glass is quite flexible, that is why you always see workman carrying glass panes vertically. If laid flat on a bench or table it will conform to the surface it is laid down on. Check it with a straight edge. You need a 4 foot long ruler anyway. Look for any low spots that you can slip a piece of paper under the edge of the ruler. Then just shim those areas with sheets of paper or card stack, then recheck with the straight edge. Work carefully while handling the glass.
Type at you later,
Dan McEntee

Ken Culbertson · « **Reply #8 on:** January 28, 2022, 11:07:09 AM »

Quote from: Brendan Eberenz on January 28, 2022, 08:27:12 AM

It will be an electric setup. I will share more about that later after I run a few tests on a motor/battery combo I am using with another Twister we were gifted. Just trying to ensure we hit a system with 5.5 minutes flights.

FYI - mine was powered by a Cobra 2820/12 using a Castle Lite 50 ESC and a Hubin F-9 timer. All pretty much the low end of good stuff. Worked Great! The Cobra had enough "Umph" to turn a 4.9 on 64' lines. Certainly didn't fly that speed. I flew on 60' at 5.4 or thereabouts.

Good Luck - Ken

Brendan Eberenz · « **Reply #9 on:** January 29, 2022, 08:35:21 AM »

Had a great night building on the Hangout call last night. Lots of great thoughts and advice. We did check the glass and it was universally flat before we started building. We got off to a slow start as we forgot to precut the Fancherized specified half ribs. Then after cutting the half ribs and sizing them up to the ribs I discovered that I had accidentally sized them to ribs closest to the fuselage. Because those ribs are sized to accomidate a layer of sheathing, all my half ribs were undersized and useless.

I got a suggestion from John Miller to fashion "strip ribs." Never heard of those, but it is essentially about a quarter inch arc of the top of the rib and the bottom. It allows for you to have the extra airfoil support that the half ribs are meant for while cutting out unnecessary balsa/weight in the middle. The other thing it allowed us to do, was get jigging and gluing the full ribs, with the ability to insert the strip ribs at a later point. This was of major value to us because Angstrom really wanted to see something come together after all our prep work.

I have attached our picture of progress. We only got the trailing edge sheathing tacked and the leading edge on. With all our measuring and checking we were slow on progress, but seem to have everything straight (and that's the important part). We will probably do some more work this weekend and I will attach a later picture of our strip ribs so people can see what we did. Thanks again to everyone on the call last night who threw out some suggestions to help us out.

Dan McEntee · « **Reply #10 on:** January 29, 2022, 09:08:19 AM »

Looking good! At this point, I would like to emphasize that you do not want to force parts to fit. If spars and such are so snug that you have to really push them into place, that causes a stress that can turn into a warp. If any spars or leading edge stock is warped, you can straighten it by drawing it across the edge of your table or glass plate to relieve the stress. Just put a slight bow in the opposite direction and draw it across the edge and eyeball it. If you went too far, just reverse the procedure with less bow in it. Once toy get the hang of it you can sometimes get it on the first try. Go through the rest of the wood strip and treat any that need it and let them rest until you do need them and check again. They usually stay pretty straight. If spar notches and such need to be opened up, make some small sanding tools to do that job. It's extra work buy pays off in the end. For any kind of sheeting, you can pre-shape it on the building board by dampening the sheet and using strips and blocks to get the basic shape and letting it dry. It's good experience for learning how to mold sheeted parts later on.
Have fun,
Dan McEntee

Tim Wescott · « **Reply #11 on:** January 29, 2022, 12:45:07 PM »

Quote from: Dan McEntee on January 28, 2022, 09:56:14 AM

Glass is quite flexible, that is why you always see workman carrying glass panes vertically. If laid flat on a bench or table it will conform to the surface it is laid down on. Check it with a straight edge. You need a 4 foot long ruler anyway. Look for any low spots that you can slip a piece of paper under the edge of the ruler. Then just shim those areas with sheets of paper or card stack, then recheck with the straight edge. Work carefully while handling the glass.
Type at you later,
Dan McEntee

I have a couple of 1/2" thick glass table tops that I use for building. One's four feet in diameter, the other one's around 3 x 4 feet. Neither of them have any detectable (using a level as a straightedge) curvature.

Thin glass that size, like 1/8" thick, will certainly bow. A 1/2" thick glass sheet over an eight foot or longer span I would want to check. But for wood working, I think you can just throw down a piece that thick and that big and trust it to have much less curvature than the wood will do by itself going from a dry day to a moist one.

Brendan Eberenz · « **Reply #12 on:** January 29, 2022, 09:17:01 PM »

Quote from: Dan McEntee on January 29, 2022, 09:08:19 AM

Looking good! At this point, I would like to emphasize that you do not want to force parts to fit. If spars and such are so snug that you have to really push them into place, that causes a stress that can turn into a warp. If any spars or leading edge stock is warped, you can straighten it by drawing it across the edge of your table or glass plate to relieve the stress. Just put a slight bow in the opposite direction and draw it across the edge and eyeball it. If you went too far, just reverse the procedure with less bow in it. Once toy get the hang of it you can sometimes get it on the first try. Go through the rest of the wood strip and treat any that need it and let them rest until you do need them and check again. They usually stay pretty straight. If spar notches and such need to be opened up, make some small sanding tools to do that job. It's extra work buy pays off in the end. For any kind of sheeting, you can pre-shape it on the building board by dampening the sheet and using strips and blocks to get the basic shape and letting it dry. It's good experience for learning how to mold sheeted parts later on.

These are all great points that are new to me. Wish I knew this when we started the wing because the leading edge was slightly bowed. The bow isn't apparent after gluing. Will definitely look for these things to troubleshoot in advance.

Ken Culbertson · « **Reply #13 on:** January 29, 2022, 10:06:01 PM »

Quote from: Brendan Eberenz on January 29, 2022, 09:17:01 PM

...the leading edge was slightly bowed. The bow isn't apparent after gluing.

Let me double down on Dan - It is too late now and probably won't matter but, as long as you are open to tips! Balsa is very easily molded when wet and hot and very stiff when cool. As a result, you should never use gluing to take out a bend, especially a LE. Heat it and see if you can straighten it and if that doesn't work wet it. We used to call this process "taking the girr out" back when I was doing mostly free flight. Something else that a lot of us know from experience, balsa will warp simply from cutting it. Flaps are the worst. A lot of us don't taper flaps for this very reason. The more you sand away, the more likely what is left will warp. Don't panic, just get it straight before you start locking it down with dope. It is perfectly OK to leave the Twister flaps untapered (chord wise that is).

ken

Dan McEntee · « **Reply #14 on:** January 29, 2022, 11:28:13 PM »

Quote from: Ken Culbertson on January 29, 2022, 10:06:01 PM

Let me double down on Dan - It is too late now and probably won't matter but, as long as you are open to tips! Balsa is very easily molded when wet and hot and very stiff when cool. As a result, you should never use gluing to take out a bend, especially a LE. Heat it and see if you can straighten it and if that doesn't work wet it. We used to call this process "taking the girr out" back when I was doing mostly free flight. Something else that a lot of us know from experience, balsa will warp simply from cutting it. Flaps are the worst. A lot of us don't taper flaps for this very reason. The more you sand away, the more likely what is left will warp. Don't panic, just get it straight before you start locking it down with dope. It is perfectly OK to leave the Twister flaps untapered (chord wise that is).

ken

What would be really great to pin to the top of this section is the information on balsa that was in the older SIG catalogs that explained the different types of grain and and how it is cut out of a log and other parts of the process. There was also a balsa density chart. There was also a great tutorial on doing traditional dope finishes and how to work with fiberglass also that could be pinned in the finishing section. Balsa is a very interesting material to work with. There is lots to learn about it and is to anyone's advantage to know and understand it's properties. After a balsa tree is harvested, it goes through a lot of abuse!! It has built up stresses while growing, gets stresses relieved and induced during the basic processing, kiln drying and then when it is finished to the point where you get it it goes through more. The lighter grades of balsa can be a pain to keep straight as you work it so you not only watch the weight of the wood but also the type of grain it has and how much it has. Building and flying even simple indoor models and gliders will show you how balsa reacts to sanding and how to do that simple task to keep it to a minimum. As Ken mentions, even just the act of running a knife down the edge of a sheet of balsa can induce a stress or relieve some and the fibers in the wood shift. Imagine what a saw is doing!! This can be countered mainly by cutting outside the finish line and then sanding to the final shape. Building up components and the use of carbon fiber strips and tow can be used effectively also. It's all part of the game and learning this stuff along the way is part of the fun and appeal of the hobby for most of us.

I have a pretty big library in my basement and it is mostly my magazine collection, but I have a large collection of books on the subject of building model airplanes, some going back to before WW-II. Some were aimed specifically at kids, and some are not but all are very interesting. I live the art work in some of the older kids oriented books I have found most of these listed on eVilBay. I find them all very useful and part of our history. I just learned over the years to surf the site and watch for what interested me and wait for the best prices. I have some that were part of programs for city summer parks department programs way back when, and even some on building solid scale identification models for the war effort that many schools across the country took part in during the early days of the war. If you like history in general, and have an interest in the history of the hobby, it can be pretty interesting once you look into it .
Type at you later,
Dan McEntee

Tim Wescott · « **Reply #15 on:** January 30, 2022, 09:51:09 AM »

Quote from: Brendan Eberenz on January 29, 2022, 09:17:01 PM

These are all great points that are new to me. Wish I knew this when we started the wing because the leading edge was slightly bowed. The bow isn't apparent after gluing. Will definitely look for these things to troubleshoot in advance.

At the level you're at -- don't worry. As long as the plane flies mostly straight it'll fly better than you. But do remember how much the LE is bowed, and look at the wing when you're done -- it'll give you an idea of how much bow is retained.

One of the nice things about that wing construction is that it's very easy to get warps out once it's covered. When you get it off of the jig you'll notice that it's super flexible in twisting -- that'll go away once you get the covering on, but it also means that if you need to twist a warp out of it you can just twist it then heat the covering to re-shrink.

kevin king · « **Reply #16 on:** February 02, 2022, 12:38:23 AM »

Quote from: Dan Berry on January 28, 2022, 08:31:19 AM

Check for flat with string pulled across the corners diagonally.

Ive tried the string method but gave up because the center of the string always seems to be low in the center and high at the ends.

Brett Buck · « **Reply #17 on:** February 02, 2022, 09:01:36 AM »

Quote from: Brendan Eberenz on January 29, 2022, 09:17:01 PM

These are all great points that are new to me. Wish I knew this when we started the wing because the leading edge was slightly bowed.

Don't worry about it, you are doing fine. At Tim notes, you can always twist it while heating it once it is covered to remove any warps. This style of construction makes it nearly impossible to keep it straight. Since the covering it nearly the only thing holding it, even if it was built perfectly straight with no built-in stress, even a slight difference in the tension while covering it will cause it to warp then. And it is not going to be particularly stable from day-to-day, either, with whatever warp it wants to have tending to come back even after you twist it to correct it. It's not really avoidable with this style of construction, tweaking it periodically with a heat gun it just part of it.

If you have solid parts like spars, and they are not straight, there are multiple ways to go about fixing them before (and after) assembly. For instance you could make up your 1/2" square LE stock from two lengths of 1/2" triangle stock, put them together and push them up against a ruler while gluing them. Or, take the original piece, split it from corner to corner, block it straight, and glue it back. It is very hard to find a single piece that is straight in all directions, building them up allows you to block them straight. The trailing edge stock on my current airplane is built up of *5* layers, and while none of the individual bits of it were remotely straight (like the .020 balsa down the middle, the resulting glued-up piece was as straight at the 48" straightedge I used to jig it up.

Ted Fancher and I assembled an ARF Strega one time. One of the problems was that the fully-finished wind had a warp, TE up at the tips. This wing was built a different way than yours, and would not easily "tweak" with a heat gun - way too stiff. Solution - take a long thin carving knife, slit the entire trailing edge horizonally from about half-span, all the ribs about 6" deep. and around the wingtip. That allowed the top and bottom half of the TE able to slide sideways, tweak it, Ted held it straight while I put on the thin Hot Stuff and pushed it together. in the new position. 2 minutes, straight (or straight enough) wing.

Brett

Tim Wescott · « **Reply #18 on:** February 02, 2022, 11:00:43 AM »

Quote from: Brett Buck on February 02, 2022, 09:01:36 AM

...

One of the problems was that the fully-finished wind had a warp, TE up at the tips. This wing was built a different way than yours, and would not easily "tweak" with a heat gun - way too stiff.

...

First, this is why I really like the Sig "stunt trainer" (Skyray, Akromaster, Twister, Banshee) wing construction for beginners -- if you build it as designed and show up to the flying field with a warped-up wing, then as long as I can find a heat gun, I can fix it right there. If I can't, I can send you home with instructions on how to fix it.

Second, there's a lesson embedded in there -- if you build a D tube wing make sure it's straight. That's where using that Brodak jig will make your life easier. Once you get the shear webs into a D tube wing, it isn't going to move in torsion. You get it right and you either live with it forever more, or you gift it to Brett until he fixes it and then steal it back

MikeyPratt · « **Reply #19 on:** February 03, 2022, 02:37:49 PM »

Tim is correct,
With just a few simple changes to any of these type of wings, you can make very a stiff wing thats light weight and strong.

Example:
Trailing edge sheer webs.
Main spar sheer webs, full length except the last rib on each wing panel.
Suspended the bell crank, supported top & bottom of the spars with 3/32 plywood that extends out to the first rib outside the sheeting.
Large gussets on the center-section sheeting.
Trim the last two ribs just like the center ribs and add cross- grain sheeting with gussets (just like the center-section sheeting).
Another simple thing to do is add a 1/16” X 1” Balsa sheeting to the ribs top & bottom of the leading edge. Note: you have to trim the ribs to get the sheeting flush with the top of the wing ribs. A lot of people sheet the leading edge back to the spar which is fine but it’s not really needed, it just adds weight.

Keep up the good work,
Mikey

Later,
Mikey

Ken Culbertson · « **Reply #20 on:** February 03, 2022, 04:55:40 PM »

As long as we have digressed into a warp fest let me add that my Twister was covered with MonoKote. The wing twisted regularly and was just as easy to straighten out. I checked it every time I went out. 5 min with a heat gun and you are ready to go. If I ever build another one, I will put in cross braces. Lighter, stiffer than shear webs and easier to add. 1/16 x 1/4 straight grained medium weight Spar to TE Cap.

Ken

Brendan Eberenz · « **Reply #21 on:** February 04, 2022, 02:00:57 PM »

Okay folks, we are back in the game. We have started on the second half of the wing. We plan on continuing the build tonight on the hangout video call. However, as a little prep, I introduced Angstrom to weilding a hobby knife and cutting some strip ribs for the half ribs we have yet to install. A special thanks to Charles Carter for putting us on to some videos on making strip ribs. Also, I believe the Fancherized plan calls for 1/16 half ribs, but that seemed rather flimsy for strip ribs, so we made them as thick as the full ribs that came in the box. Hopefully we get pretty far on the build tonight. Should have more pictures coming.

Brendan Eberenz · « **Reply #22 on:** February 05, 2022, 02:29:05 PM »

Worked a lot on the wing during the hangout last night and a little bit today. Have all the strip ribs in and complete. Now its a matter of joining the two half wings together. Below is a picture of me and my best buddy working on the wing last night.

Ken Culbertson · « **Reply #23 on:** February 05, 2022, 03:45:47 PM »

Quote from: Brendan Eberenz on February 05, 2022, 02:29:05 PM

Worked a lot on the wing during the hangout last night and a little bit today. Have all the strip ribs in and complete. Now it's a matter of joining the two half wings together. Below is a picture of me and my best buddy working on the wing last night.

I built mine the same way. When it is time to join you can take it off of the jig and slip the tubes half way into both wings and join them. Put on the bottom center section sheeting then take the rods out.

You are a lucky pair.

Ken

john e. holliday · « **Reply #24 on:** February 05, 2022, 04:53:04 PM »

That is looking great and a handsome pair of gentlemen.

Brendan Eberenz · « **Reply #25 on:** February 05, 2022, 08:32:43 PM »

Quote from: Ken Culbertson on February 05, 2022, 03:45:47 PM

I built mine the same way. When it is time to join you can take it off of the jig and slip the tubes half way into both wings and join them. Put on the bottom center section sheeting then take the rods out.

I planned on just connecting spars, trailing edge sheathing and leading edge. But that was just off the top of my head. Your point about the botton center sheathing makes sense as well. However, wouldn't that limit my ability to install a bellcrank and platform or does that further help me establish how the bellcrank fits in and rests. I haven't really worked much with putting a bellcrank IN a built up wing. I'm open to thoughts on that process as it approaches. By the way. I have some Kevlar thread arriving Monday. I plan to use it for my leadouts. We also plan to install adjustable leadouts.

Ken Culbertson · « **Reply #26 on:** February 05, 2022, 09:57:02 PM »

Quote from: Brendan Eberenz on February 05, 2022, 08:32:43 PM

I planned on just connecting spars, trailing edge sheathing and leading edge. But that was just off the top of my head. Your point about the botton center sheathing makes sense as well. However, wouldn't that limit my ability to install a bellcrank and platform or does that further help me establish how the bellcrank fits in and rests. I haven't really worked much with putting a bellcrank IN a built up wing. I'm open to thoughts on that process as it approaches. By the way. I have some Kevlar thread arriving Monday. I plan to use it for my leadouts. We also plan to install adjustable leadouts.

Maybe you might be right about the bottom sheeting if you use a "floor" mount. I use nothing but floating. I also use a different form of tube jig that lets me build the wings separately then join them on the jig. I use arrow shafts and keep the arrowhead inserts in. They join together with a piece of 6-32 all thread. On the BC Mount, I use two pieces of 1/16 plywood for a top and bottom mount glued to the spar. I fill in the gaps on the top and bottom with soft balsa so that the stress of the bellcrank is absorbed by the LE sheeting. This obviously is not a Twister but this is how I did my Twister.

Note the scraps on the LE & TE joints. You can do the same thing on the backside of your TE.

Ken

Brendan Eberenz · « **Reply #27 on:** February 06, 2022, 05:35:33 PM »

We have a single wing!!! We fused the two half wings together and things look pretty good. Going to scab a few strips in at the connection joints to reinforce them. Then it's on to the bellcrank, tips, and trailing edge. Here is a picture of a happy builder with what we got so far.

Tim Wescott · « **Reply #28 on:** February 06, 2022, 05:49:38 PM »

Quote from: Brendan Eberenz on February 06, 2022, 05:35:33 PM

We have a single wing!!! We fused the two half wings together and things look pretty good. Going to scab a few strips in at the connection joints to reinforce them. Then it's on to the bellcrank, tips, and trailing edge. Here is a picture of a happy builder with what we got so far.

The center sheeting will be plenty of reinforcement.

Don't forget to take the jig rods out before you put the wing tips on.

Brendan Eberenz · « **Reply #29 on:** February 07, 2022, 08:25:26 AM »

Quote from: Tim Wescott on February 06, 2022, 05:49:38 PM

The center sheeting will be plenty of reinforcement.

Don't forget to take the jig rods out before you put the wing tips on.

Good point on the sheeting reinforcing things. Also have to believe that there is someone out there that forgot to remove the rods before putting the tips on. I don't want to be THAT guy.

Tim Wescott · « **Reply #30 on:** February 07, 2022, 09:03:36 AM »

Quote from: Brendan Eberenz on February 07, 2022, 08:25:26 AM

Good point on the sheeting reinforcing things. Also have to believe that there is someone out there that forgot to remove the rods before putting the tips on. I don't want to be THAT guy.

I haven't done it yet. I expect that some day I'll be looking at a nice straight wing, complete with tips and jig rods.

Dan McEntee · « **Reply #31 on:** February 07, 2022, 10:15:01 AM »

If one were THAT absent minded, That would be a good reason to use carbon fiber tubes for jig rods. They would be light enough that you probably wouldn't notice anything in the finished weight of the airplane!
If there is any way to make a mistake n building a model, I'm sure I have probably already done it!
Type at you later,
Dan McEntee

Ken Culbertson · « **Reply #32 on:** February 07, 2022, 04:51:40 PM »

Quote from: Dan McEntee on February 07, 2022, 10:15:01 AM

... carbon fiber tubes for jig rods...

Brendan Eberenz · « **Reply #33 on:** February 13, 2022, 11:39:25 AM »

It has been a moment since we have charted our progress. We've continued to make progress on the wing build and spent some time today shaping the trailing edge. Today was Angstrom's first run with a razor plane to expedite balsa removal. We snapped some pictures of the razor plane and sanding process. We have been prepping for the bellcrank and control system. Will be putting the tips and adjustable lead outs on soon. Also got to round the leading edge. Lots to do, but the little guy is hanging in there.

Brett Buck · « **Reply #34 on:** February 13, 2022, 11:55:43 AM »

Quote from: Brendan Eberenz on February 13, 2022, 11:39:25 AM

Also got to round the leading edge.

Don't scrimp on the razor plane and the sandpaper there, pointy is bad. Make it a continuous arc from one side to the other.

Brett

Brendan Eberenz · « **Reply #35 on:** February 20, 2022, 09:54:00 AM »

Another update and pictures on our progress. We installed a tip weight box. We got Kevlar thread running through our adjustable leadouts. We got the bellcrank mounted and went with 3/32 wire with a z-bend. For those following my other post about control systems, I was nervous about using the bellcrank to flap wire provided with the kit because it didn't have a z-bend and the wire was too thick for me to put one in. Finally, I have a picture with Angstrom and our progress to date. Still need to sand the wing and round the leading edge then the wing is pretty much done until flaps.

We do have a question about monokoting the wing. Obviously it is easier to guage the straightness of the wing when it is not running through a fuselage. Would it be a problem to monokote the wing first, make sure it is straight, then work towards gluing it to the fuselage? That may not be the conventional way, but for rookies like us, I think it would be easier to see and correct the wing without the fuselage in the way.

Dan Berry · « **Reply #36 on:** February 20, 2022, 10:22:00 AM »

The wing is easier to cover when it isn't attached to the fuselage.

Tim Wescott · « **Reply #37 on:** February 20, 2022, 11:15:16 AM »

Quote from: Brendan Eberenz on February 20, 2022, 09:54:00 AM

Would it be a problem to monokote the wing first, make sure it is straight, then work towards gluing it to the fuselage? That may not be the conventional way...

That is at least one conventional way. A nice "rookie finish" way to do this would be to Monocoat wing, fuselage, and tail pieces separately, then glue them together. There will probably be some awkwardness around the wing/fuselage joint (these never seem to fit perfectly, even with kits). The important thing is (A) don't get too heavy, and (B) seal everything so that exhaust goo doesn't get into the wing/fuse joint. I usually paint the fuselage on profiles, so that wing/fuse joint is finished with microballoons & epoxy (i.e., Sig Epoxolite or the Brodak equivalent), then painted. You could do that, too, just on top of the 'coat.

Dave Hull · « **Reply #38 on:** February 20, 2022, 10:39:28 PM »

I have not used kevlar for many modeling tasks. But it is known to cut thru most plastics if it works back and forth. In this application, there might not be enough sliding motion on the leadout-to-bellcrank attachment to precipitate any problems. It might last indefinitely.

Has anyone else been using kevlar for leadouts on plastic bellcranks? Which bellcranks? (What material?)

Dave

Brett Buck · « **Reply #39 on:** February 20, 2022, 10:49:06 PM »

Quote from: Brendan Eberenz on February 20, 2022, 09:54:00 AM

We do have a question about monokoting the wing. Obviously it is easier to guage the straightness of the wing when it is not running through a fuselage. Would it be a problem to monokote the wing first, make sure it is straight, then work towards gluing it to the fuselage? That may not be the conventional way, but for rookies like us, I think it would be easier to see and correct the wing without the fuselage in the way.

I have no problem straightening it with it assembled (and, hate to break the news, you might have to do it anyway, because these sorts of wings are not particularly stable over time, you may be tweaking it for the first year or two). But there is no harm doing it separately, either.

For this sort of airplane, I would very strongly recommend iron-on covering for the with and tail, and 2-part epoxy paint for the fuselage. That will allow you to install the wing and tail, and then add the fillets (Super-Fil or whatever), then paint over them. But to do that, and apply the Monokote first, requires you to carefully map out where the fuselage needs to go, and leave about 1/8"-3/16" bare wood on either side. The fillet goes over the edge of the covering to seal it up better.

The epoxy paint is easy, a little filler, a coat of color, sand it, another coat of color, good to go. Of course it will not be front-row, but you will be surprised, and it is also completely bulletproof. Lap the edge of the paint over the fillet and a little out on to the covering, that will seal it up perfectly.

Brett

jerry v · « **Reply #40 on:** February 21, 2022, 06:41:40 AM »

Brendan,
If fuselage was laser cut, sand that burned surface in the gluing area of the wing an stab. When you will dry fit the wing into fuselage before covering- put the masking tape on the wing in the mating area to simulate the thickness of the covering.
When covering of the wing and stab - leave uncovered area on the wing and stub narrower by 1/16 or 1 mm than actual width of the fuselage in that area. And have extra 1/16 Monocote going in the wing and stab opening. Bare wood will make better joint and extra Monocote will hide the seam. When time come for gluing the wing, use 30 min epoxy, slide wing with glue back and forth, wipe extra glue with alcohol and position everything square. After glue sets, use more glue to fill one seam at the time and wipe immediately with alcohol. So initial glue does not have to be perfect, there will be gaps to fill later. Epoxy will turn yellow after time, it will be visible on the light color of the cowering. Having four hands you and son can put the 5/32 strip of Monocote in the seam area with the heat gun .
To answer your question, yes, cover the wing, stab and the fuselage first, and glue all components in the “ARF style” . Because you decided to make it electric, you don’t have to worry about fuel proofing and vibrating from the wet power engine. Monocote is quicker to cover and does not stink.
Some pictures of my built Rongmaster and P-40 ARF :

Jerry

jerry v · « **Reply #41 on:** February 21, 2022, 09:17:42 AM »

Brendan,
Next thing to worry about is to make choice : rear or front mount of the electric motor))…

Jerry

Ken Culbertson · « **Reply #42 on:** February 21, 2022, 01:40:46 PM »

Quote from: jerry v on February 21, 2022, 09:17:42 AM

Brendan,
Next thing to worry about is to make choice : rear or front mount of the electric motor))…

Jerry

My recommendation is to get one of the printed mounts from Okie Air. It is a front mount and super simple to install in a profile. You can get them straight or with built in offset. The one I used on my last profile came with 2 degrees offset (by request). I also recommend that you use a pusher prop and rotation to start if you have a source for props. A pusher is considerably more friendly on takeoff which can be a huge benefit to someone starting out. The battery is something you must consider. Size matters, especially on a profile. Batteries have wildly different sizes and weights. You will need about 5" between the back of the motor and LE of the wing. You want enough battery to give you about 30 seconds of flight time past the time it takes to fly the beginners pattern and still have a minimum of 20% unused. Most 2820 size electrics will do that on a 4s 2200 battery and there are a bunch out there. Make sure that you pick a motor that will take a larger "s" value if you need it. Another tip is if you plan on putting the battery on the inside and the E-goodies on the outside - if you don't recess it into the profile, move the wing offset out another 1/4" to keep the balance. The Twister is a .35-.46 size plane. A Cobra 2820/12 for example is a .40 equivalent. Don't go much larger than that. Putting too large a motor on a small plane forces it to run outside of it's peak performance envelope. A really good combination is a Castle EdgeLite ESC with a Hubin FM-9 timer. Only problem is the high cost of the programming box. I am sure there are a lot of others that will recommend something appropriate. What you need is a constant speed timer and an esc that supports it. Save the "active" timers for later, but not too much later!

Good Luck!

Oh, on the covering. It doesn't matter much which you do first. I prefer to fully complete the plane before covering. Keep in mind, you can finish over MonoKote. Fuselages are really difficult to cover once the wing and stab are attached. You might want to put the base covering, whatever it is, on before attaching the wing and stab but not the final. Also remember - MonoKote does not play well with others when use on fillets. Outside curves are simple, inside are next to impossible. Paint the Fuselage!

Ken

Brendan Eberenz · « **Reply #43 on:** February 23, 2022, 10:26:10 AM »

Thanks for all the suggestions guys. I do think we will monokote the wing ahead of time (probably on the video call this Friday) and separate from the fuselage. Since it will take a moment to get the fuselage in order, perhaps monokoting it now will give us additional time to see how it settles and make further heating adjustments before we have to glue it into place. The tips on how to fuse it all together were helpful and appreciated. As for the nose, I purchased a Universal Electric Conversion kit from Brodaks. https://brodak.com/universal-e-electric-conversion-for-profile-fuselages-front-mounted-motors.html Dennis Adamisin has shown them several times on the video calls so I thought we would take the plunge and try to do things in a more organized way (as opposed to velcro and rubberband the electrical setup on there any which way we can get it to kind of fit. The picture I attached is straight off the Brodak site in case you haven't seen it before

john e. holliday · « **Reply #44 on:** February 23, 2022, 12:47:24 PM »

Good move.

Ken Culbertson · « **Reply #45 on:** February 23, 2022, 01:12:41 PM »

Quote from: Brendan Eberenz on February 23, 2022, 10:26:10 AM

As for the nose, I purchased a Universal Electric Conversion kit from Brodaks.

Excellent choice. Made one almost identical for my Twister, RIP. Wish they had this one at the time, would have saved me a bunch of work.

Sorry about the bird. Only Pix I had left. We have a bird problem at Hobby Park. Sometimes they win, these didn't.

Ken

Howard Rush · « **Reply #46 on:** February 24, 2022, 01:39:35 AM »

Might not hurt to start building a backup model with metal leadouts.

Brendan Eberenz · « **Reply #47 on:** February 28, 2022, 04:52:49 PM »

Another update. Covered the wing this weekend. I've got about 30 rolls of monokote and the kid decided to go flashy. If you look at the attached pic you will see what I mean! Time to start looking at the fuselage... OR... we have a second Twister kit and may get another wing up and ready since we just completed one. To be continued...

Dan Berry · « **Reply #48 on:** February 28, 2022, 05:32:50 PM »

Quote from: Brendan Eberenz on February 28, 2022, 04:52:49 PM

Another update. Covered the wing this weekend. I've got about 30 rolls of monokote and the kid decided to go flashy. If you look at the attached pic you will see what I mean! Time to start looking at the fuselage... OR... we have a second Twister kit and may get another wing up and ready since we just completed one. To be continued...

Flashy.
And heavy.
He's making progress!!

Brett Buck · « **Reply #49 on:** February 28, 2022, 07:20:06 PM »

Quote from: Brendan Eberenz on February 28, 2022, 04:52:49 PM

Another update. Covered the wing this weekend. I've got about 30 rolls of monokote and the kid decided to go flashy. If you look at the attached pic you will see what I mean! Time to start looking at the fuselage... OR... we have a second Twister kit and may get another wing up and ready since we just completed one. To be continued...

Make sure you have enough bare wood to accommodate the fuselage and maybe 1/8-3/16" additional on each side, to give something for the fillets to stick to.

My first "big" airplane - a Ringmaster Jr - also had chrome monokote, because that was all I could get for free. Very unforgiving stuff, as I recall and I certainly did not know what I was doing at the time, so it was *ugly*.

Brett