FT Versa is always crashing

[Random_rc]

Hello,
i have build a FT Versa a while a go. i finally got round to flying it.
when i launched it the first time at about 70 % throttle it went about 10 meters and nose dived right into the ground. so i tried again but with 100% throttle and it did the same thing. i did this about 5 -10 times and i was throwing harder too. I still couldn't get the plane to fly, it was like it didn't have enough power, but i powed the Versa with full throttle and thought it was fine. the servos were working. i have now broke it so much its like a mini blunt nose and can't put the battery in because the battery strap ripped through a chunk of foam. and been in Australia the Foam is about $7.50 each sheet. it was a pusher style.


Specs
Motor: Hextronik 24gram 1300Kv
Propeller: APC Style 8x4 (the ones you can get from Hobby-king)
Esc 30 Amp hobbyking (the blue one(i had from a previous plane))
Battery 2200Mah
Servos: HXT900 9gram

i don't know why it keeped crashing, i was pulling full up elevator (checked that it was the right way


please can some one help me!

 

[makattack]

Welcome and sorry to hear of your problem flights! Hopefully you can easily repair that damage. Try using hobby ply or even old / used gift card plastic stock to reinforce the nose where your battery goes.

I've read posts from other people who have had simiar problems and they all seem to boil down to these causes:

* Center of Gravity Issue - the Versa requires a good amount of additional nose weight. How much did you put in? Your motor is pretty light, but even with a 24g motor and 2200mAh battery, it probably needs at least 30-50g of weight (wild guess)
* Thrustline issue - one guy on the forums found that he had to add some up thrust by shiming his motor mount about 1mm, I think.
* Prop on backwards (you'll never get enough thrust if that is the case. The writing should face the nose / into the wind even with pusher.
* The most obvious, cause it seems, is not having enough reflex or up elevator mechanically dialed in. With sticks at neutral, I have about 12-15 degrees of up elevator on mine, and it flies straight hands off.

 

[Craftydan]

Wings are tough to launch, but fortunately they're pretty tough to take it. Even so, so many things can go wrong on launch, learning to get them airborne is a learning curve in itself.

Hard to pinpoint what's going wrong on the details here . . . Hate to ask you to risk it again, (wings are tough, but that has limits) but can you get a video of it? Or a more detailed description of it's attitude as it approaches "hard nose down"? 10m is a long way to fly level then spontaneously crash from trim issues.

 

[Random_rc]

Thanks for the help.
The elevators are about 45degrees throw for elevator at max. I think I might try a bigger motor and what motor would be good. The prop is not on backwards. I was pulling full up and it still wasn't going level or up
And hobby ply is hard to get and expensive, but I have got some spare gift cards to reinforce.

Thanks for you help

 

[Random_rc]

Thanks for your help
The plane is missing a wing tip and battery strap ripped a chunk of foam, but I can put another battery strap next to it and take a video of it , I was going to build another one later in the year. But before I do that I will take a video of me flying and show you( maybe in a day or 2 ) .
Thanks

 

[Craftydan]

No rush on our end -- Whenever you get to it Random.

45 degrees is plenty of defelction -- might even want less, but that's not the issue on launch.

The 24g bluewonder style motor is a little lightweight for the versa -- on 3S it's capable of ~85w, and that prop should be plenty to put that much energy into the air . . . and you might want more thrust, but it should have gotten airborne. Slow and underpowered, but airborne. What's your AUW (All Up Weight)?

 

[Winglet]

Hello Matt,

Sorry you are having problems. You can get through this and it is worth it. This is the best flying model I have ever built. I have built 3 so far and rebuilt 1 so I'm a obvious believer and I have a ton of experience flying them. I can't add anything to what the other guys have already said because they are spot on. The 4 points that makattak listed are absolutely critical. Do you know what reflex is? It is absolutely critical on this airplane. It wont fly without it. (the other points are just as important too) I don't think your motor is an issue. I flew my first one with a very small motor the first few flights and it flew fine, just not spectacular.

Keep trying and keep us posted on how it is going on. We will get you flying right.

Mike

 

[Random_rc]

Hello,
The all up weight is 760grams. and does any one have any recommendations for a bigger motor.

also i flew the versa inverted (from launch) and it flew better but it still went down, so makattack said that i might have to change the trustline.
also do you want some photos of it (sorry that i didn't add them)

thanks for you help

 

[Random_rc]

here is the photos after it got destroyed. it looks like a normal versa but now damaged


i made my own firewall out of 6mm (i think) plywood
the trustline looks fine to me
also one last thing how would you recommend fixing the plane and reinforcing it

 

[Craftydan]

A little more power on a 4.5-6" prop:

http://www.valuehobby.com/power-systems/brushless-motors/outrunner-airplane/emax-cf2805-outrunner.html

A LOT more power on a 6-7" prop:

http://www.hobbyking.com/hobbyking/store/__12919__D2826_6_2200kv_Outrunner_Motor.html

You'll have to find local sources, but either of those are good. Plenty of other options too -- you'll likely want at least 100w/lb, which means you'll want ~160W motor/prop combo.

 

[Random_rc]

i was going to use the versa for FPV and out of these two what would you go for out of these. so would this be a good motor.

160W:
http://www.hobbyking.com/hobbyking/store/__12916__D2822_14_Brushless_Outrunner_1450kv.html

the CG was behind the mark (tail heavy) so i don't think cg is that much of an issue because otherwise the plane would keep stalling ( i checked this before i crashed (i forgot to add it in)) but it was nose diving ( like it was nose heavy)
when i get the new motor would it help to tilt it up. then it would compensate for the downward force.

 

[quorneng]

I must say I would agree with Craftydan than a Blue Wwonder is really a bit small for 760g.
With too little thrust it is not so easy to judge whether is is actually nose or tail heavy as particularly with a 'wing' the end result tends to be the same - it dives into the ground! The important bit is exactly what it was doing before it hit the ground hence the request for a video.

I do fly a Blue Wonder as a pusher and on a 2s in a plane that weighs that much but it is a glider type aerodynamically efficient airframe not a flying wing.

 

[Craftydan]

You can go with that motor, but if you plan on adding more gear, that means your AUW is going up, and buying *only* what you need won't be enough.

Your ESC can support either motor with the right prop and the bigger motor is only ~10% more for potentially twice the power (granted, if you double the power, you'll need to step up your ESC). Only other thing is you'll need to buy the right prop . . . but get used to buying spare props -- some may last for a while, but they're consumable items.

For what you have now, either will work. The choice is yours


As far as the CG, it doesn't work that way during launch of a wing. In stable flight it's easy to see it change trim as it changes speed, or one of the handful of odd behaviors a tail or nose heavy plane will do as it enters stall, but too many dynamic forces and impulses are acting on the frame at launch to say it's not tail heavy because it noses in. I agree completely with quorneng -- at launch, a wing is VERY hard judge tail-nose misbalance stalls without seeing exactly how it got there.

The CG marks on FT planes have quirks, but the ones that are off favor *tail* heavy, and the Versa is spot on. Wings *have* to be spot on -- you don't have a tail to counterbalance the pitch axis torques between the Center of Gravity and the Center of Lift. The thinner the dimension, the less stable the airframe will be in that dimension, so flying wings and planks tend to be high-agility, low-stability in pitch, so CG problems become magnified.

As for thrustline, hold off on that. When you get it back together, set your CG as close as you can, erring toward nose heavy, power it up with no throttle and give it a toss at the horizon. With just a little reflex it should glide to the ground without any more help from you (not that you aren't important in this, but we're checking trim). If the glide test works, trim isn't an issue, so repeat, kicking on 1/4-1/2 throttle about 2m out. What does it do? pitch up/down? Put a thin washer between the motor and mount on the top bolt for up, bottom bolt for down, and check it again.

 

[airhawk]

are you running the recommended power setup cause that's important to get the proper performance especially if its not the right motor power theirs not going to be enough power to climb can you give more details on how it climbs heres what ft recommends you either get the beef package or get them all separate Complete Electronics Kit - Swappable Power/Electronics "The Beef"

MOTOR (Option 1) - "THE BEEF" (Motor only) GT2215/09 70g

MOTOR (Option 2) - Suppo 2208/14 1450kv Brushless Motor (Park 370 equiv.)

MOTOR (Option 3) - "Blue Wonder" 2712-12 24g

Servos (Option 1) - Hextronic 9 Gram Servo

Servos (Option 2) - Suppo SP-90 9g Micro Servo

ESC (Option 1) - TURNIGY Plush 25amp Speed Controller

ESC (Option 2) - Suppo 18A Brushless ESC

Battery (Option 1) - Turnigy 1000mAh 3s 20C Lipo Pack

Battery (Option 2) - Turnigy 1800mAh 3s 20C Lipo Pack

Battery (Option 3) - Turnigy 2200mAh 3s 20C Lipo Pack

Prop (tractor) - Slow Fly 10x4.7 prop

Prop (pusher) - APC Style 8x6 prop p.s if you have the recommended electronics then this is useless

 

[Craftydan]

Airhawk,

The Versa will very much enjoy flying with the Emax GT2215-9, but it'll be perfectly happy with a smaller motor than that. In fact, motor option #3 was what the original poster was using. A little light on power but workable.

The recommendations are just that: recommendations.

There are a nearly infinite number of parts combinations that won't work, so the recommendations are useful, but there are many more that will also work.