FT-40 Trainer

SoarAllDay

Junior Member
My flying club is at a public park. We often have many spectators that we want to get behind the controls and enjoying RC and part of the club, but nobody wants to own/repair the plane(s). I'm impressed by the FT swappable series and I want to do a FliteFest-inspired-build-tent except every nice weekend.

What I like about the FT Swappables... very simple, very cheap, very easy to get someone in the air quickly and people get excited about them.

What I don't like (as a trainer plane)... They're too light for training; the venerable Great Planes PT-40 (just one example) is over-strong for taking hard hard landings and heavy for staying stable in windy conditions and slow.

I am open to any suggestions; but here are my thoughts...

The best FT model to start from is the FT Storch (*EDIT* was Mighty Mini Trainer, but switched to FT Storch from thread feedback). I would change...

Landing Gear:
- Big fat mono gear on the CoG using the stock pod's landing gear hard points with out-runners on the wings made from straws.
- Thicker wire for mono wheel
- Wheels: 1/2" foam with the pop-rivet mandrel idea. I'll use a whole saw to make a bunch ahead of time and let them glue it together.

Wing
- Straight chord simple/moderate dihedral
- Long thin glider-like (8:1 AR)... slow roll rate, easier to see, easier to land (even cart wheel)
- Optional 60% span ailerons; because it's windy in Kansas.
- rubber banded
- do not trim the tips, keep them straight to avoid tip stalls
- twist in washout with a heat gun also for benign stall

Fuselage:
- Double the side wall foam for stiffness and add weight
- Standard size swappable pod
- Glue gift cards between foam layer around wing, landing gear and pod pins to spread those point loads and improve longevity.

Battery:
- Use a bigger 1800-2200mah batter mostly for weight and secondarily for stick time.


Does anyone have any advice/opinions/thoughts/concerns?
 
Last edited:

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
Those changes are interesting and good for a trainer . . . but not for the Tiny trainer. A larger version of the same plane? Absolutely, but the stock FTTT is too small to take on much added weight gracefully.

For the Not-so-tiny trainer, I'd still lean toward 3 channel with strong poly or dihedral, and landing gear is nice for recovery, but ground handling is not a skill you'd use to hook a prospective beginner -- if the airframe is still small enough, I'd go for tail dragger and hand launch, using the wheels for the graceful landing.

. . . Better yet . . . Why not the Storch? Bigger and heavier, but still floaty, slow and STOL. Easy to reinforce and easy to connect a steerable tail wheel to the rudder. The wing needs a bit more re-enforcement than stock design, IMO, but otherwise she's a sweet flying plane capable of hooking nearly anyone ;)
 

SoarAllDay

Junior Member
How will this work...

I think I'd like the club to provide the build materials (foam/hot glue/knife blades) for free. We'll have cutting templates for the big parts made from thick plastic. And we'll keep a donation can around.

Ideally they will build the plane, we'll drop in one of our swappable pod with club owned electronics and get them flying that day. They take home a plane that reminds them they can come back any time and go flying.

Ideally I want to print onto the foam:
- Club logo & FT logo (hey you started it)
- links to free/online flight simulator
- links to flitetest.com to build their own swappable pod and buy components.
 

SoarAllDay

Junior Member
Why not the Storch? Bigger and heavier, but still floaty, slow and STOL.


Yes totally... all those changes based on the Storch.

I am a big fan of hand launching, my FT pod has never even had gear.

For very initial training a quick hand launch and flop onto the grass is fine. But for 10th-ish flight where the student is just doing landings/take-offs it's a lot easier to have 4-6 folks (it gets very busy at our club) in the air at the same time if they can touch and go. That's a hard skill for a novice with a taildragger. Just saying it's not ideal and if I can think of a way... would really be nice. We also have a hard surface.
 

SoarAllDay

Junior Member
One more attribute of a club trainer... We don't want a totally dirt simple plane that any totally green pilot can semi-self-solo (with many crashes).

We always buddy box new pilots with club instructors. We aim for the best flying, heaviest duty plane we can find. The goal isn't getting in the air. It's getting back down in one piece over and over. It's a subtle and crucial difference that yields a far faster transfer of skill confidence minimizing frustration and failure.

BTW, I am a huge fan of training with gliders; they are gentle and benign and easier to see. I want a really big narrow wing. Not a short tick one.
 

SoarAllDay

Junior Member
Landing gear... What about the glider configuration of a single main and straw out-runners? Built into the airframe, remove the pod gear. Main wheel on the CoG is by far the most stable/easiest for any ground operations; especially T&G.
 

SoarAllDay

Junior Member
FT-40 Fuse Sketch

I like the storch wing. My only alteration is a one-piece solid box spar out of the same wooden paint sticks except the paint sticks go vertically front/back and are cut into a very fat V with the 15 degree dihedral. The single sheet of foam is the double and forms the top/bottom of box and extends out beyond the paint stick just as it does on the storch. I'll draw this up.

As for the fuselage, I've attached a doctored up sketch I made. One big mono-wheel. The fuselage is faithful to the old PT-20 in profile, including the rounded windshield. It will be a one piece fuselage 30" long with ample room for the swap pod. I think I might be able to make this a two-sheet 20x30, one for the wing and one for the fuselage. I'm not entirely confident I can get the wings on one sheet. FT-40 Fuse Sketch.png
 

SoarAllDay

Junior Member
Progress

I built my prototype, but it's far from what I had envisioned or perfect;

FT40.jpg

FT40 Bottom.jpg

- The horizontal is too small, so I'll build a bigger one and install it
- The fuselage needs to be fatter(taller and wider) as it interferes with the landing gear attachment skewers and has an ugly profile.
- I don't think I like the mono wheel arrangement, it's too "rickety" and the straw out-runners don't work well
with a high-wing (they're too long to be effective) I will go back to the stock tail wheel.