FTFC20-Build-Ruary Challenge by Vimana89(Build Skill 2.5, Pilot Skill 3)

[Vimana89]

Build Skill: 2.5 Pilot Skill: 3
Entries
1.) Custom Tandem Wing Trainer V1
2.) Custom Tandem Wing Trainer V2
3.) Flite Test Vector(speed build kit)
4.) Custom 4ch Canard Plane + Plank Plane
Bonus Entries
5.) Custom Swept Wing Stick Plane
6.) Custom Forward Swept Wing V Tail Plane
7.) Custom Three Step Air Foil Swept Wing Plane

 

[Vimana89]

Entry 1; 4ch Tandem Trainer
Pics

Plans link

reasons for choosing this plane
I had many reasons for choosing this plane. First and foremost, I needed a solid 4ch trainer to help me learn to coordinate rudder and ailerons or elevons. I have always wanted to build a tandem wing plane since I began the hobby, and recently built a nice 3ch stick tandem plane with flat plane wings that flew impressively well. I figured if that flew, why not something a little fancier and more purpose built, like a trainer with under cambered wings and a protected prop?

Build Log
Build process and pics are described and documented in detail in the thread below. This is a summary.
1.) 2/2/2020
Drew quick sketch, designed fuselage template, fabricated fuselage and wings, including camber and elevator, made VS/rudder and mounted to rear wing. Challenges were in designing a fuselage that would be light and strong while fitting the camber of the wings.

2.) 2/3/2020
Added electronics and mounted wings. I took it out for a maiden and had a bad camera angle, otherwise I'd include the little footage I had. It flew ok but handling was a bit off. At this point this still relates to build because I looked carefully, and even though I tried to get things even, the front wing was misaligned a bit, which contributed to lackluster handling. I used the glue gun tip, my pen knife, and a heated up wire, and with some difficulty and damage, removed the sturdily mounted front wing and aligned and re-mounted it, repairing the damage and reinforcing with an extra strip of foam on top.

Build Rating
2(at least by my standards), straight forward but with a unique fuselage requiring minor paper removal/curving on the nose. Standard FT techniques like B fold and basic under camber air foil.

Maiden Video
Sadly, this is not a first maiden due to technical errors and reasons. This is launch two of a re-maiden after re-aligning the wing and getting my camera properly charged and positioned, however I think it does the plane justice.

Fly Rating
1easy, meant to be a 4ch trainer

Closing/Reflection
My work with tandem planes is still just beginning and there's a lot more experimentation and variation in the future, but for the intended roll and purpose of this version as a 4ch trainer, I'd say I did pretty well, although it could perhaps use slightly larger elevons with a little more throws, and maybe a hair less camber. As far as do's and don'ts...don't be afraid to try tandem wings, do be extra careful with things like wing alignment when mounting/gluing parts down for final assembly.

After More Testing
Noticeable wing rock in a lot of instances and a bit of pitch instability, plus the sluggish/choppy elevon banking, has lead me to conclude that the under camber of the wings threw something off about the general tandem design. The plane did, however, fly well enough to build some 4ch muscle memory, so it did fulfill its roll to some extent, and the next version which now is using these electronics is continuing to fulfill that roll much better.

 

[Vimana89]

Entry 2: 4ch Tandem Plane Version 2(flat plate wings)

Pic

Plans

Reasons for Choosing This Plane
Basically the same reasons for choosing the entry 1 tandem "trainer", with the addition that I know I can make a tandem wing plane that performs much better and doesn't have the wing rock that most likely has something to do with the dual under camber wings. I have made a 3ch tandem with flat plate wings on a stick that flew great, so all I really want to do is step that up to a clean 4ch build with a box fuselage. Hopefully this will be the tandem design that gets it right.

Build Log

About 6 Total Hours
1.) 2/10/2020: Sat down in the evening and brainstormed, and came up with my measurements for fuselage length, wing span and chord, and style of wing(straight and no air foil), as well as things like distance between the wings. I chose straight wings over the swept wings of the '39 Special I had considered using, for space and wing area compromises. I came up with a 30" fuselage, 22" span by 6" chord wings with 14" of space between them(this measurement was based on my 3ch stick plane version with 20" wings). V.S. and rudder are aft of the rear wing and elevons.

2.) 2/11/2020: In the morning, I drew up the fuselage template and all the rest of the parts except the full fuselage. In the late afternoon and evening, I continued my work, cutting out the template and doing the fuselage, then cutting out the rest of the pieces(including bevels and tab/slot) and assembling the bare air frame.

3.)2/12/2020: Spent some time in the morning doing aesthetics/decals/color scheme. I set the air frame aside until late afternoon, and finished the build(electronics and all) by early evening.

Build Rating
1-1.5/5, as simple as it gets with 4ch and a full box fuselage

Fly Rating
1-1.5, as basic as it gets, but a bit more responsive than some would argue is absolutely ideal for a first plane or dedicated trainer

Maiden

Closing/Reflection
This one went really well, and I'm satisfied with its performance as a smooth flying and reliable design, and a solid proof of concept for a basic 4ch tandem wing plane. The plane meets the goal of performing equal or better to the 3ch stick version I made with flat plate wings before this challenge began, and there is no more wing rock like on the under camber version with the high mounted pusher prop I made for "entry 1".

Don't "fix what ain't broke", like my going from successful prototype with flat plate wings to a version that just threw under camber into the mix and threw something off somehow, resulting in annoying wing rock and sluggish/choppy elevon response. Do stick with a custom design or general idea that feels like it has potential, but a few flaws. It might take another version or two, but you will be surprised how quick you get it.

Overall, this is a textbook case of success, the plane came out exactly like I intended and fixed design flaws of the previous version. I designed this plane to be as basic as possible a proof of concept for a 4ch tandem wing design, but also clean, practical, and high performance, since it will be filling the roll of my go-to 4ch trainer. I'm also glad I decided to use landing gear on this one, it works great and protects my prop. The only things About this design I will probably change in the future is that I will probably go from flat plate wings to a KFM style air foil, and I will mount the landing gear in a stronger manner.

 

[Vimana89]

Entry 3, FT Vector(speed build kit)

Pics

Plans

Reasons for choosing this plane
I chose this plane as a late entry for the Vector group build, because I wanted to add another FT kit to the collection, and when I found out it was provided with a 4ch option, even better. The Vector looks unique and is a pretty flexible plane with a decent flight envelope from what I gather, so there's a lot of good reasons that lead to me choosing this one.

Build Log

Total build time: between 5 and 6 hours
I build this plane a little at a time over a few days instead of all at once. The first build session I started with just popping out the pieces and doing all the cuts and foam removal from each piece. After looking at the nose area thinking I had to remove the foam and noticing it wasn't coming off easy, I realized this area was intended to only remove the paper(thankfully before I did any real damage). The next day, I took a break from building and then finished up over the following few days.

When it came time to start gluing and assembling stuff, the nose was no problem, but I closed the fuselage up totally before mounting a motor or installing electronics. I went back over the instructional build video after the fact, which mentions not doing that. I wasn't too worried though, because I figured I'd find an easy enough fix. The next step was to paint the fuselage and nose, and add vinyl and decals to the wing and vertical stabilizers. I didn't do paint on the wings to avoid warping, especially with one sheet thick, flat plate wings.

By the time I got around to electronics, linkages, and assembly, I figured the best workaround for the prematurely closed fuselage was to connect the ESC to the motor mount, hook up the receiver, connect two servo extensions to channel one and two, and drop all the electronics down through the fuselage into their various positions as they were connected to the motor before finally mounting it in place(I used a 50mm motor mount and none of the swappable stuff, which I had intended anyway with or without making the mistake).

This speed build kit took my as long as some of my simple custom designs. While I did not have to draw anything up or cut anything out, the design, from a build standpoint, was significantly more advanced and complex than my own so far(similar to the Charlie), and had a much higher parts count. The painting and bit of extra time added by working around the fuselage thing were other considerations that contributed to build time.


Build Difficulty Rating
2/5, straightforward/modest

Fly Difficulty Rating
2/5, straightforward/modest

Maiden Video

Closing/Reflection
A nice plane that I need to spend some more time with and tweak to improve the elevator authority and punch-out. Part of it is my build slop, and part could be CG and trim. As far as the design, I like it aerodynamically. From a build perspective, I prefer to design my own planes simpler, with as low a parts count possible and the least complicated techniques required to get a desired result. To be fair, from the standpoint which this plane was designed(on a CAD program, with laser cutters, etc.), it is not overly engineered at all(similar to the Charlie, although the Charlie could use just a couple less tabs and slots).

As far as do' and don't's; Do refer to a build video if you not 100% sure about a marking, technique, or order to do something in. Do support FT and pick up a speed build kit every now and then if you enjoy their planes and either have trouble with some of the building techniques, or just want to cut down on the excess build time. Don't jump the gun and make any cuts, remove any foam, or glue/close/finalize anything before being 100% sure(again, refer to video guide if not).

 

[Vimana89]

Entry 4, Custom Canard + Plank Plane(s)

Pics

Plans

Reasons for Choosing This Plane
My reasons for choosing to try a canard plane were simple curiosity and not having successfully built and flown one yet. I went with a big chord elliptical wing because it looked unique on the canard plane, and I wanted something with good wing loading and a nice speed envelope. My reasons for choosing the plank plane were similar; curiosity, not having built and flown a successful plank plane before, and not wanting to waste the air frame if I could still make something flyable from it.

Build log
detailed build log entries posted on the thread. This is a summary.

Build Rating
1/5
Fly Rating
*Canard Plane: N/A
*Plank Plane: 3.5/5, relatively straight forward, but somewhat sketchy

Maiden Video

Closing/Reflection
The canard plane was sort of a spur of the moment decision to try the canard plane, and an area I have no real experience or previous success in. I did not take a thorough approach to the design, I just sort of tried something (which works out often enough, but no such luck this time). The plank plane flew ok, but was squirrely, twitchy, and extremely finicky with CG and trim, and its flight envelope was less than a lot of more stable and easier to fly planes I have designed, built, and/or flown, although it had some nice stability on straight shots at modest speed, and decent flips.

I had a feeling I wouldn't be too into planky "combat" style" planes much, and although part of that is probably imperfect CG and thrust angle and trim on my part, I have no strong draw to try one again in the near future, but down the road, who knows? As for a canard design, that's a stronger possibility, but again, not something I foresee trying again in the immediate future.

 

[Vimana89]

Bonus Entries

Entry 5, Custom Swept Wing Plane

Pics

Plans

Reasons for Choosing This Plane
I figured it was time to start working with simple air foils, so I watched a vid about KF airfoils and explained about pitch problems with flat plate wings at high speeds(which I've experienced with a few of my planes when they got up to high speeds). I decided that was all the more reason to start learning how to make some simple air foils that would be durable and more stable at high speeds. I opted for a simplified version of the KFM that's basically just glue and no fold, at least until I practice and get better. This is kind of how they do it on the FT delta anyway as far as I know.

At first I though about doing a familiar style of wing like a delta or straight wing, but decided to try something new. The only reason I hadn't done a basic swept wing before was because it needed an air foil or spar to be strong enough and all I was making for the longest time were flat plate wings. I figured this would be a good style of wing to try while experimenting with the KF style air foil. The design is extremely basic, but a completely new experience to me.

I chose the salvaged stick and elevons from my stick tandem air frame because the stick was the perfect lightweight fuselage to test my new design concept, and because I didn't want to waste the nicely linked servos and elevons that could still be used. To be completely transparent, the stick tandem(including the linkages and controls I re-used) was built before February started, but I built it for the stick tandem with no plans or knowledge that I'd end up using it for any of the FTFC20 entries. I also did have to cut down and rework the old rear wing into the new tail plane, and remove the old front wing from the stick.

Build Log

1.)Total Approximate Hours: 3(Including 4ch upgrade and elevon extensions)

I built this plane as a 3ch plane first over one day with a total build time of two hours, one hour at a time with a break in between. I started by stripping the front wing off of my old stick tandem in the boneyard, and converting the old rear wing into a swept tail plane, retaining the 3ch elevons. I drew up a basic swept wing with about a 28" span. The main challenge would be to design and draw up by hand any sort of real KFM fold, which would be no problem for a straight wing, but swept wings and deltas are a bit trickier.

As far as I know, the FT delta just folds it over on one side and glues it, leaving foam core leading edges, unlike a lot of KFM versions I see with full foldovers and smooth or even curved leading edges. If this works on the delta, than just gluing the top layer on from a separate piece should be just as functional, so that's what I ended up doing for simplicity's sake, until I practice fancier techniques. Other than this consideration, designing and building this plane was a no-brainer.

2.) After flying the plane successfully as 3ch, I decided to take @L Edge's advice and convert it to 4ch. I added a spare 3.7g servo I found, a rudder, and I also extended the elevons by 50% chord after making some clearance cuts for the rudder. I went from using a 650mAh 3s or 850mAh 2s to using a 3s 850 or compact 1100 to get the CG back in line and provide more flight time. These additional upgrades added about an hour to total build time, and ended up improving the plane's maneuverability and wind resistance considerably.

Build Rating
1/5, as basic as it gets
Fly Rating
1.5/5, as easy as it gets without being a first plane/dedicated trainer

Maiden Video
Maiden, 3ch

4ch Flight w/Rudder and Elevon extensions

Closing/Reflection
I consider this one a big success, because I ended up with a great flying plane that didn't require a lot of time and effort to build, but broke new ground by being my first swept wing design(and first swept wing plane I've ever built and/or flown before) and gave me my first real success with KF style air foils(or air foils in general on my custom planes). I'm glad I decided to convert this one to 4ch, it went from good to great with that little adjustment, and I'm really enjoying flying it.

I look forward to working more with both KFM air foils and swept wing planes in the future, and I'm already planning to make a bit larger swept wing plane with a three step air foil, longer and more highly swept wings, full ailerons, and a full box fuselage. This one will definitely have a bigger motor than the 1806 A pack motor.

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Entry 6, Custom Forward Swept Wing Plane

Pics

Plans

Reasons for Choosing This Plane
I wanted to try another simplified KFM air foil on a wing type I hadn't tried before, and I've wanted to try a FSW plane for a long time. The V tail elevons/ruddervators were built and linked as part of my old four wing plane long before the start of this challenge and saved me a good little chunk of build time, but they were not made with plans or foreknowledge of using them for one of my entries now.

Build Log

Approximate Total Build Time: Between two and three hours

I built this plane over one night in a couple of sittings. First, I cleaned up and lightened the old V tail piece and attached it to a spare wooden stick spar. I then drew up and cut out the wing pieces and couple other body pieces, assembled the wing, and painted it. In retrospect, I should have not painted the thin part of the wing because it did warp a bit, although the warp is even, adding slight dihedral and a slight up curve from leading to trailing edge, which I reasoned should not be detrimental to performance with a tiny bit of trim. after that, assembly was a no-brainer.

Build Rating
1/5, as simple as it gets
Fly Rating
2-2.5/5, straight forward, but not a trainer or beginner plane, and is finicky with CG and not completely stall proof. Stable and maneuverable, but a little challenging with launch and landing.


Maiden Video

Closing/Reflection
I was about to possibly scrap this one because it was still flying a bit tail heavy on a 1300 mAh battery, but giving it another chance with a 1600, a bit of trim, and a different prop was well worth it. This plane isn't perfect, is a tiny bit quirky, and it finicky with trim and CG, but it's been pretty fun to fly, provides a use for my 1600 mAh battery, and would actually make a decent camera/FPV platform with its stability and flight duration if the design were developed a bit more.
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Entry 7, Custom Three-Step Swept Wing Plane

Pics

Plans

Reasons For Choosing This Plane
After testing out the mini swept wing plane I made for this challenge, I immediately wanted to try a larger, more ambitious and highly swept plane with a profile similar to the English Electric Lightning, and try a three step KF style air foil. There's a plane called the "Blitz" on Outerzone I've always liked, which is basically like what I built, based on the Lightning, but has a much smaller tail plane and the ailerons are elevons. The major difference is my three step air foil and use of a small T tail horizontal stabilizer. I wanted to make this one a four channel plane to begin with no retrofitting later. I also wanted a plane that was fairly straight forward, but would push my build skills to the best of what I can currently do.

Build Log

Approximate Total Original(pre-maiden) Build Time: 7 hours and 30 minutes
Approximate Extra Post-Maiden Build Time (servo adjustments, nose rebuild) 1 hour 30 minutes

I knocked this plane out over one day working a lot of the day straight through with minimal breaks. I started with the wing before even drawing anything else, assembling it from the few big pieces of foam I had left. If I were doing any proper folding this would be a more challenging wing to make, but with more expedient methods still took me about two hours just for the wing. After that, I drew up everything else at once and cut it out, assembling the fuselage, mounting the V.S./rudder, motor, and doing servos and linkages. Next, I taped down my electronics, hooked all the cables up(without mounting the wing yet), and set up/dialed in the plane on my TX before mounting the wing to the fuselage.

I kept the design simple and parts count as minimal as possible, but this one still took some real effort. I kept the wiring pretty clean, using through-wiring and keeping most of it in the fuselage.

Build Rating
2/5 straightfoward

Fly Rating
1.5/5 gentle

Maiden Video

Closing/Reflecting
This one was a bit rough to get off the ground, but a lot of that was small build flaws and errors. Once I got this plane flying properly, I was blown away by the stability, smoothness of handling, and the almost scale-looking manner of flying(moves a lot like a real jet). I learned a bit about positioning the control horns and clearance concerns as far as using a KFM air foil, and I learned how to work around it no problem. I also realized the way I'd been haphazardly mounting landing gear(the built in gear motor mount) was causing a lot of shock stress and damage to the nose and motor mount area every time the plane landed. It was already noticeable using it on the tandem, but this plane's weight made it even worse.

The only thing I'd change about this design is maybe a bigger motor. The F pack radial seems to go through batteries fast keeping this plane flying with a draggy three-step air foil and 14.5-15oz of all-up weight.

 

[Vimana89]

reserved for any additional information

 

[Vimana89]

I'll be starting with the tandem. Here's a rough sketch, a bit more sophisticated than my stick version. I want a simple under cambered air foil on the wings for more lift and drag, and a high mounted pusher for prop protection as this plane will be a 4ch trainer with a cool tandem twist.

 

[Vimana89]

Fuselage design for the tandem. It will be a B fold.

 

[Vimana89]

I'm going to finish the tandem today and possibly maiden if the wind stays reasonable. I should post some progress here and discuss the build a bit. Everything is lining up really clean so far and the build looks nice.

 

[Vimana89]

Not much air frame work left before electronics and assembly. The plane is a simple premise, but this one was interesting to design because it was the first time I used undercamber wings so I had to build the fuselage in a way that's light and simple, but fits to the camber of the wings while having a high mounted pusher behind the front wing like an Explorer. All of this made a pretty unique fuselage design.

 

[Vimana89]

Completed and maidened. There was some wind, and it doesn't like wind at all. My camera was at a messed up angle so not sure how much footage I got, but the plane flew and was quite stable, but not as responsive as the flat wing stick tandem. Turning feels a bit...I guess like the Charlie, but more pronounced, it has this quality where the response is not instantaneous and it seems to resist turning with elevons just a tiny bit, but is maneuverable enough, just requires harder throws or the addition of rudder. Will test further when I get a chance to fly with no wind. I'll see if I got any useable footage.

 

[Vimana89]

So looking at my plane, there is a slight wing misalightnment on the front wing which probably makes he handling clunkier than it should be. I'm going to try and heat up the glue in the cracks with either the tip of the glue gun or a hot wire, and try to remove and remount or at least nudge the wing into a straight even alignment.

 

[Vimana89]

That was exceedingly rough and didn't get it off without a bit of damage, but I did make everything straight and repair the plane up. Not quite as pretty but not too noticeable.

 

[FoamyDM]

AWESOME work! This is like a Burtan- you-old-Fogey. I should get my Tolmekian Corvette moving.

 

[Vimana89]

Quick color scheme enhancement with some black vynil sticker paper, dollar store letter/number stickers, a FT decal, and the label from the bag of HQ Ethix brand props I use in two types on this plane.

 

[Vimana89]

I got a bunch of foam now🤔🤔🤔🤔. I got too slender deltas and the big ones a bit better, so I'll borrow the 1806 off the small one for something. Either that, or tackle the four wing plane rebuild. I'm just wondering to make a delta, a canard plane, or something else crazy with that 1806.

 

[Vimana89]

decided on my 4th entry, a custom 4ch canard plane. This will be build log entry one, 2/4/2020: Came up with design concept, drew a rough sketch, and drew a fuselage template on a piece of foam too beat up to use for actual parts, with the slot positioned for canards at a 4 degree angle.

 

[Grifflyer]

That'll be very cool!!

 

[Vimana89]

Build Log 2/6/2020 Template for fuselage made, everything else drawn up. I drew up two VS/rudders, a basic one and a classier one that extends downward some, which is the one I'll use.

Entry 2:air frame mostly assembled, will do linkages and mount the wing. Only trouble is I had a brain fart and cut through the elevon so I just cut them off and re-taped them.

Entry 3: Finished up and ready to maiden.(did not get pics before maiden, but did not look much different from the empty air frame except with electronics)