Help! Tiny Trainer CG problems

[Adam F]

I just finished assembling my first plane, the Tiny Trainer, but I'm having some problems. When I put the battery into the nose of the plane in the same manner as is shown in the build video the plane is nowhere near balanced when I put my fingers on the CG marks (at least I'm assuming that's what the dots on the bottoms of the wings are). Probably something not too hard to fix, but I'd appreciate some input.

Thanks!

 

[hankflies03]

which way does it tip? pics are always helpful.

 

[Goudbeekje]

Have the same at the moment.

I placed battery under the wing. Tommorow 2nd flight as last time the rudder extension came loose.

I guess the cg is a bit more to the leading edge.

 

[Adam F]

It is quite nose heavy. I suppose I could put the battery behind the power pod, but that would be a lot of things crammed in there.

 

[JasonK]

It is quite nose heavy. I suppose I could put the battery behind the power pod, but that would be a lot of things crammed in there.

looks like your battery is much bigger then the recommended ~650-850mAh battery for the Tiny trainer, so yes you will have to position it farther back to get the CG correct. I suspect your battery is about 2-3x the mass of the recommended sized one.

 

[Merv]

It is quite nose heavy. I suppose I could put the battery behind the power pod, but that would be a lot of things crammed in there.

Feel free to rearrange things to make them fit and handy to get to.
You need to arrange things to make the plane balance on the CG marks. If anything you want the plane slightly nose heavy, that is while balancing the plane on the CG marks, it’s OK if it tips slightly to the nose. You definitely don’t want it tipped to the tail.

 

[Inq]

It is quite nose heavy. I suppose I could put the battery behind the power pod, but that would be a lot of things crammed in there.

That's easy to fix... just move the battery backwards till it balances as shown in the video. The harder problem is when the battery is full forward and still the plane is tail heavy. Then... you have to add extra weights (that make flying harder) forward.

 

[Foamforce]

In the video it appears that they’re using a smaller 2c battery. it looks like a 650mah or maybe the 800mah that they sell with it on the store. Since you have a 2c 1800 mah battery, it’s two to three times heavier than that.

You’re going to have to move it quite a ways back to balance. You might even need to add some weight to the tail if you can’t move the battery far enough back.

If you can, it would be better to get a smaller battery. Besides the COG difficulty, it will also make this plane harder to fly. It will still fly, but you’ll have to fly it faster all the time and you’ll stall and probably crash more often. That said, it will still fly and you can still learn on it, it will just be more difficult.

Good luck and have fun!

 

[Adam F]

Thanks for the info! I got all the electronics from a guy who recommended an 1800 mah battery so I would have more flight time but from what has been said it seems a bit unnecessary. I think I'll need to return them and get some smaller ones because they're too big to fit anywhere else in the nose without forcing the foam apart. Any recommendations on how powerful I should get and what will the flight time and handling be like with them?

Thanks!

 

[Merv]

...Any recommendations...

The TT will fly well on a wide range of batteries. The 1800 may be at the higher end of the range but it’s not outside the range. With it you can easily fly in excess of 10 minutes. A smaller battery will shorten the flight time, a 600 to 800 will be 6-8 minutes.

Double the MAH will not double the flight time. It will maybe add 50% of the flight time due to the increase in weight. There is a point of diminishing returns when a larger battery doesn’t add any flight time.

 

[Foamforce]

Any recommendations on how powerful I should get and what will the flight time and handling be like with them?

You probably knew this, but mah is how long it will run, not how powerful it will be. So an 800mah 2s will be just as powerful as the 1800mah 2s that you had. Bumping up to 3s gives you 50% more power, along with 50% more weight.

On the store, they sell it with either an 800mah 2s, or an 850mah 3s, so I would consider those official recommendations. The 2s will be better for a beginner because it will fly slower and because it will be 33% lighter, so it will stall less. I don’t know the flight time because I don’t have a Tiny Trainer, but it seems like Flite Test designs most of their planes so that you’ll get seven or eight minutes per flight. Get two smaller batteries instead of one big one for longer flight time and you’ll be happier with it.

Good luck!

 

[Adam F]

Thank you both very much! I did not know that, and I'll buy accordingly.

 

[dylanbeaudette]

A lot of good advice on battery selection for the TT. We love our TT, especially with the aileron wing. We typically fly with 650-800 mAh 2S, but will occasionally use 850mAh 3S for a faster flight.

I’m not sure what to expect with our recent conversion to an F motor…

 

[tomlogan1]

A lot of good advice on battery selection for the TT. We love our TT, especially with the aileron wing. We typically fly with 650-800 mAh 2S, but will occasionally use 850mAh 3S for a faster flight.

I’m not sure what to expect with our recent conversion to an F motor…

It is a whole different plane. Take it easy on the first few circuits and then let it rip. It's pretty quick compared to the 2s.