FT Tiny Trainer - BUILD

[Lavochkin]

Finished my TT

Finally finished my Tiny Trainer 3 channel, complete with color scheme matching pool noodle slice wheels. Not yet maidenized......

 

[Lavochkin]

If you use your radio to limit the travel of the flight you lose what's call resolution in the controls. Meaning for every degree your servo travels per point of resolution in the computer controlling it. If you limit the travel in the radio the controls might get choppier.

Kurt,

In my case I have the control rod in the hole closest to the servo arm pivot point and had to set travel limits in the radio. Are you saying I should drill a hole closer to the pivot point to limit travel instead of using the travel limit in the radio?

Thanks, Matt

 

[Torf]

Kurt,

In my case I have the control rod in the hole closest to the servo arm pivot point and had to set travel limits in the radio. Are you saying I should drill a hole closer to the pivot point to limit travel instead of using the travel limit in the radio?

Thanks, Matt

Ideally, your throws should max out at 100% in one of the holes on the servo. If you have to dial down to 60% or less, and still have room to drill a hole on the servo arm, then go for it, being mindful of z-bend interference against the servo body. It's worth a try.

It's better to have full deflection at 100% throw than full deflection at 50% throw. In my opinion, unless you are looking for some really precise flying, +/- 20% from 100% on the transmitter is going to be OK.

By the way, that plane looks beautiful! You might want to raise the tail a bit with a skid. It will help keep that stabilizer looking nice if you fly off rough surfaces.

 

[Lavochkin]

Torf,

Thanks for the complement on the plane! I do have a tailskid, but it was on a soft blanket when I took the photo. Also, I looked at the servo arm situation, and the z bend would interfere if I drilled a hole close enough to make a difference. The limit I set to keep the elevator from contacting the rudder was 20%, set the same on the rudder although there would be no interference.

 

[Torf]

Torf,

Thanks for the complement on the plane! I do have a tailskid, but it was on a soft blanket when I took the photo. Also, I looked at the servo arm situation, and the z bend would interfere if I drilled a hole close enough to make a difference. The limit I set to keep the elevator from contacting the rudder was 20%, set the same on the rudder although there would be no interference.

So was it 20% down from full throw, or down to 20% from full throw? If the former, then I don't think you'd notice the loss of resolution very easily. If the latter, then you might have issues trimming the aircraft. I doubt that is the case though.

The only other way to fix servo travel issues that I am aware of is to make a longer or shorter hole in the control horn (longer makes for less throw, and shorter means more throw all else equal), or trying a different servo.

That thing looks ready to go fly to me! Let us know how it goes!

 

[Lavochkin]

So was it 20% down from full throw, or down to 20% from full throw? If the former, then I don't think you'd notice the loss of resolution very easily. If the latter, then you might have issues trimming the aircraft. I doubt that is the case though.

Down 20% from full, or to put it another way, I'm using 80% of full throw.....

 

[cranialrectosis]

I finally got my Tiny Trainer out to the field yesterday and with a little help from the guys at SCORCH we got it trimmed out and flying. The key was expo and dual rates. I had WAY too much throw on the ailerons for a beginner trying to maiden from a hand launch.

I will play with the rates more today as I had it too 'numb' to complete a barrel roll or Immelmann. Somewhere in there is the right roll rate for me.

Also after yesterday's adventure I have cut the notches in the trailing edge of the wing and expanded the BBQ skewer to keep the rubber bands from slipping and jamming up the ailerons. I also dropped my front landing gear. The wheels were too small to roll on grass at the local field so I have to hand launch anyway. They might be able to prevent me from breaking the prop on every landing but I need to figure out a way to mount them so the force of a hard landing doesn't fold the wheels up next to the fuselage.

I find it amazing how many things change when you are actually flying the thing.

This is a great plane to build and fly. It handles MUCH easier than the F-22 and I love having 4 channels to play with.

Nice plane FliteTest!

 

[Yaroslaw]

Hi all First post here

Tiny Trainer (why tiny???) was my first Scratch Build after small wltoys cessna 182cm. While I was figuring out everything I ordered way too powerful electronics from China (good for bigger swappables, actually) only to find out after a build that Tiny should get smaller motor and ESC and servos etc... So I was flying 40g motor, 30g Esc, 9g servos, 60g battery and a lot more packing tape then needed
And it flew with aileron-less wing pretty good. But trying to fly with 4-ch sport wing I get tip stalls, CG problems and all that stuff. So I'm thinking of rebuilding a tail (it is pretty bad looking, after all crashes, fuse was rebuild already once) with 5g servos and changing power pack to less powerful (I can get 700g of thrust with mine now... oops!)

So the questions are:
What is empty weight of TTrainer made from DTFB? We do not have DTFB here, so I kinda "make" it and need to know how far I can get with strengthening foam.
What is descent AUW for TTrainer? With trainer wing and sport wing for some aerobatics?
What thrust-to-weight ratio do we need for sport wing for aerobatics, and power (Watt, thrust)?

Good motor type for that matter? I have spare 17g ZMR 1804 (bought for TT, but when I get it I thought already it would be not enough for it, may be for smthing smaller) and HK Donkey 2204 (27g, gives 270-320g of thrust, 80-100W power on 3s). Can I get it work with Donkey or should I look for something more powerful within that range of weight (my current Emax is only 39g!). Though weight diff is looking small, smaller motor also means smaller ESC, and 10A and 20A ESCs are pretty different in weight (10g and 30g on what I have currently).

PS 3-ch wing for me now is just boring, but I plan to teach my GF to fly on it with a buddy-box.

PS2 any ideas of good use for 1804?

 

[dgrigor02]

Good motor type for that matter? I have spare 17g ZMR 1804 (bought for TT, but when I get it I thought already it would be not enough for it, may be for smthing smaller) and HK Donkey 2204 (27g, gives 270-320g of thrust, 80-100W power on 3s). Can I get it work with Donkey or should I look for something more powerful within that range of weight (my current Emax is only 39g!). Though weight diff is looking small, smaller motor also means smaller ESC, and 10A and 20A ESCs are pretty different in weight (10g and 30g on what I have currently).

2204, 3S and a 0645 propeller should do well. I ran emax 2204 with 3S and 4S and had alot of fun but the wing gets stressed out. Wanting more aerobatic don't add any dihedral to the wing just straight. Full throws just increase your expo to be less sensative in middle of stick. Still not super tight rolls but will roll decent. Get comfortable with that and want more fun, throw that same setup on the DAS Mini stick: http://forum.flitetest.com/showthread.php?14491-(Das)-Little-Stick-Parkflyer-Plans, you for sure won't be bored anymore.

 

[Kurt0326]

Yaroslaw, first of all welcome to the family.

I think a lot of the questions you have about the motor is covered in the article on post 1 this thread. The guys at flitetest guys recommended the power package A I think. Also for foam board, you might like this thread "Adams Readi-Board shipped to the UK (and international)" http://forum.flitetest.com/showthread.php?21146-Adams-Readi-Board-shipped-to-the-UK-(and-international)-for-%A31-66-per-board-)

 

[Kurt0326]

Yaroslaw, first of all welcome to the family.

I think a lot of the questions you have about the motor is covered in the article on post 1 this thread. The guys at flitetest guys recommended the power package A I think. Also for foam board, you might like this thread "Adams Readi-Board shipped to the UK (and international)"http://forum.flitetest.com/showthread.php?21146-Adams-Readi-Board-shipped-to-the-UK-(and-international)-for-%A31-66-per-board-)

 

[dayve]

...
So the questions are:
What is empty weight of TTrainer made from DTFB? We do not have DTFB here, so I kinda "make" it and need to know how far I can get with strengthening foam.
What is descent AUW for TTrainer? With trainer wing and sport wing for some aerobatics?
...

I just finished building mine. It's on the bench waiting for the receiver to come in the mail. The specs say the iA6 receiver weighs 6.4g (we'll call it 7). My painted plane with the trainer wing and a a 74g battery is 272g . Add the receiver in for a grand total of 279g. I know 8g of that is paint. I weighed it before and after because I was curious. Just the unpainted DTFB parts with no electronics is about 120g. I haven't built the sport wing yet, so I can't help you there.

Seems like your 2204 would work.

 

[Lavochkin]

Someone suggested we put details such as weight in our posts, so here is mine..

non-aileron wing 82 grams
fuselage (w/receiver, esc,servos, etc) 154 grams
power pod 21 grams
850mah battery 71 grams
total 328 grams

Maiden flight - crash from about 5 feet up during takeoff
Damage- broken prop, loose battery upon impact broke bottom fuselage joint in front

So, the battery was fairly far back to get it to balance, there apparently was not enough area of velco attachment. I must rethink the mounting. Anyone else have this problem and what was your solution? Thanks!

 

[Ron B]

let esc hang as far back as possible and mount the rx as far back as possible

 

[Lavochkin]

let esc hang as far back as possible and mount the rx as far back as possible

Thanks.

Already done that. As you can see from the photo, the servos are mounted back towards the tail. To determine position during the fuselage build, I connected the motor, esc, rx and servos and stretched the wires out, therefore determining how far back I could mount the rx and servos. The rx is mounted just ahead of the wing trailing edge.

I kinda have a bias against adding ballast weight, but may have to...

 

[Corbarrad]

So, the battery was fairly far back to get it to balance, there apparently was not enough area of velco attachment. I must rethink the mounting. Anyone else have this problem and what was your solution? Thanks!

How's the CG without the landing gear? those struts seem like they put quite a bit of weight in front of the cg.

If you want to keep the gear you could probably move the attachment points back towards the wing dowels while keepin the wheel position the same. I think you could even move the wheels back to where they're directly under the wing leading edge and still be pretty safe from noseovers on landing..

 

[Yaroslaw]

Yaroslaw, first of all welcome to the family.

I think a lot of the questions you have about the motor is covered in the article on post 1 this thread. The guys at flitetest guys recommended the power package A I think.

Actually, it isn't. They actually recomend ZMR 1804 that I have, but I'm pretty sure it would not be enough for sports version, having 320g of thrust on WOT, which is less or equal to flying weight (good for high and slow passes though). As you can read my post, I was interested in "sport setup", as on Nutball and my flying wing I already do some aerobatics with loops, rolls and stuff.
Also, "recommended" setup can only be used with exact same foam without any reinforcement (like minwax, paint or tape), as it's adding weight quite a bit.

Also for foam board, you might like this thread "Adams Readi-Board shipped to the UK (and international)"http://forum.flitetest.com/showthread.php?21146-Adams-Readi-Board-shipped-to-the-UK-(and-international)-for-%A31-66-per-board-)

THANKS!!! That looks AWESOME (with David's voice) Just need white relisted!

So, the battery was fairly far back to get it to balance, there apparently was not enough area of velco attachment. I must rethink the mounting. Anyone else have this problem and what was your solution? Thanks!

I attach my battery to plane belly, around an oval hole for launching, which serves purpose of cooling ESC and getting power wires from esc to battery. I fly on a field with a grass, so no landing gears - battery still stays ok.

 

[Torf]

How's the CG without the landing gear? those struts seem like they put quite a bit of weight in front of the cg.

If you want to keep the gear you could probably move the attachment points back towards the wing dowels while keepin the wheel position the same. I think you could even move the wheels back to where they're directly under the wing leading edge and still be pretty safe from noseovers on landing..

That is the same LG design that I have had great success with, and what you are saying is correct. It's a sturdy LG and best placed on the wing dowels for balance. As long as the front strut sticks downward at roughly 90* from the front wing dowel, the plane should behave itself on the wheels. If the front strut bends backwards closer to the CG, then you might start to see problems.

I fly using a Zippy 850 mAh battery which for proper balance in my plane needs to be pushed WAY back to the rear of the power pod. It's barely attached on my TT with center mounted servos. A little wedge of foam or wad of kleenex jammed in there helps keep it in place. On my other TT with tail mounted servos, the battery has to come forward quite a bit.

 

[Lavochkin]

That is the same LG design that I have had great success with, and what you are saying is correct. It's a sturdy LG and best placed on the wing dowels for balance. As long as the front strut sticks downward at roughly 90* from the front wing dowel, the plane should behave itself on the wheels. If the front strut bends backwards closer to the CG, then you might start to see problems.QUOTE]

Torf,

I copied the LG concept from this thread and went back through the posts, and it was indeed yours. Great concept! Pretty light, and in my maiden crash the wires popped off the skewers, no doubt absorbing some of the force that might otherwise have caused damage.

I attached to the front wing and rear motor mounts because as a novice pilot, I was leery of nose-overs. Since it seems you had no problems, perhaps I should move it back using just the wing mounts. Also, I noticed in your post that you wrote that you removed the right thrust and added down thrust on the motor. How are they working out?

Matt

 

[Torf]

I attached to the front wing and rear motor mounts because as a novice pilot, I was leery of nose-overs. Since it seems you had no problems, perhaps I should move it back using just the wing mounts. Also, I noticed in your post that you wrote that you removed the right thrust and added down thrust on the motor. How are they working out?

Matt

The reworked powerpod actually works really well. I seem to need zero right thrust on this plane, and added a bit of down angle (using washers) to get things to behave in a neutral fashion. My second Tiny Trainer is setup with servos in the rear, and I actually cut the front of the pod so that the firewall sticks out 3-4 mm farther at the top. Works like a dream!

Others have reported that the right angle is necessary, so it seems that all planes are not created equal.

Glad the gear seems to be working well for you! I intended the gear to be able to absorb an impact by rotating backwards. Saved my plane one time when I came screaming out of a dive a bit too late. I dragged the gear right through the weeds at at least 30 mph, ripping them clean off and losing a couple small rubber bands, but sparing the prop and plane all damage.