So, i have a 2 year old Tiger Trainer. It has been through hell and back. I lost interest last year, but am hoping to fly it again this weekend. I found a nice big field at a local park ( and even another guy had his plane out there ). Anyways. I took it up to fly it today, and the engine wouldnt start. First the engine got choked in fuel, so i drained it, then the glow ignitor wasnt charged, so i had to give up. Anyways, onto the trouble:

While carting the hoss about my house, the tail caught a door and cracked the rear part of the fusilage. It sent a HUGE crack (Maybe 6in long ) down the rear of the plane. This made the horiz. stablizer aweful loose, so i ( Having no extra balso ) broke a paint-stirring stick in half, and CAed it to both sides. I checked the Stabilizer, and it felt nice and sturdy.

My question is, what will this most likely effect. I'm not toooo worried about it crashing ( Though i'd liek it to stay afloat, i've also got a 4-Star 40 lined up waiting for it's guts ), i just want to know what i'm in for. My main problem i think will be that the CG is a bit back now. How much will this effect the plane?

I know all of you are laughing your asses off at my newbish nature, but hey, i'm just having fun with my POS trainer from 2 years ago. Ok... so... what do you guys think?

Check your c.g.
Fix it if it needs it.
Check to see the stabilizer is aligned as it was.
The problem isn't all that serious as long as the repairs get everything back more-or-less where the parts were.

Yep... the most serious problem willbe if the CG was shifted to far back by the weight of the materials added.

Noseheavy is sluggish on the controls. Tailheavy is very quickly planted nose first in the dirt.

Thanks guys, i'll check my CG, i'm guessing just adding some dead weight inthe front should do the trick?

[:-]

Popsicle sticks (like your paint stirring stick) is one of the strongest and cheapest repair materials.....If your CG is right on it won;t make a bit of difference......Just glue and enjoy......Just make sure that the stab is aligned......I have an old ALPHA trainer that has been knocked around and used by about 10 students...the Hoizontal stabilizer is probabely off a 14" and it still flys like a trainer.

HAVE A BLAST!!!

Hey DLDUDE....that was supposed to read 1/4 inch.....NOT 14.......

Yes... if the CG has been shifted back to where its outside the recommended range for the model... a little weight in the front will cure it.

The reason you can get away with allowing it to drift behind the recommended range on a trainer is... trainers tend to specify a forward CG for added safety. You get the CG further back... the aircraft becomes more aerobatic... but stalls get more likely to result in spins and spin recovery gets harder.

As your flying skil increases... you can experiment wil letting the CG get back as far as 30% MAC on the trainer. (I bet the plan's location of rearmost is 25%...) Some models are still controllable with the CG as far back as 37% MAC... that's about as far as any I have found would be stable enough to safely fly.

I know one RC pilot that could probably handle a plane with CG further back then 37%... but even he wouldn't like it. He balances about everything at 35% (which was quite entertaining when he balanced a flying wing at 35%... the design was unstable further back than 18%... but this guy was good enough to fly it that way.)

Please show the airfoil selection that is "balanced" at 37-%. That would be one weird as* airfoil wouldn't it????
The center of gravity can't be behind the center of lift, unless you can defy the laws of physics........well maybe with a killer gyro..........

Jetts

There are lots of model airplanes that balance further aft than 37%. It's quite common in the free flight world where the tails are large and a long way from the wing. Even in the current model sailplane world it's not uncommon to see folks balancing at between 35 to 40%. It's all about the aircraft neutral point rather than any fixed airfoil based constant.

Now that flying wing with the CG at 35% would have been a merry handful for sure......

golden rule, ugly planes last longer

The only problem with a c.g like that on a flying wing... would be locating all the parts after impact. They'd be really close to the launching point though. Most likely right behind the tosser.

is that the tosser that thought 37% was a smart idea on a flying wing?

I've balanced some free flight models as far back as 50% with lifting tails. Sorry, I should have been more specific.
I think my some of my deltas flew fine with a cg of 40-50%, but as I said one weird a** airfoil.
Or maybe I'm just "super duper good"
Tosser? I'm thinking yes.

Jetts