ORIGINAL: boosboy
Hi,
I've just passed my BMFA "A" a month ago and got a black horse super air which I've been doinf all sorts of great things above and beyond the "B" schedule with on a little OS46LA.
So, I thought I'd go up a level and treat myself from the BMFA website as there was a CAP232R for sale (£100) with servos (S3001's), switch, battery checker, Dubro low bounce wheels, plastic wing and landing gear bolts and a OS55AX engine (that way if I do crash at least I've got engine servos etc which would have cost over £100 anyway!). The person I bought it from said it is great, hovers, harriers, almost unlimited vertical etc on a 12.25*3.75; he also gave me a 14*4 prop. Just add reciever and battery to go. He has also moved the rudder servo under the elevator as he said it was better down their and less flex on the conrol rod, so extra weight at the tail?
Now for my concern. I know sometimes people move the CofG back to make it easier for 3d stunts etc. But the CofG on this is supposed to be 83mm, I've got it at 100mm with my battery and r606fs reciever fitted up front!!!!!!
Will this be unfliable? Should I add weight to the nose, would have to the the firewall and engine mount I expect? Don;t want to crash it as it looks great, already concerned that they SNAP!!!!
Thanx.
Get a yardstick and get the answer yourself (on any plane, not just that one) in about 5 minutes.
http://www.geistware.com/rcmodeling/cg_super_calc.htm
And quit thinking of the CG as one fixed place. It ain't that big a deal to have it somewhere other than the sacred place the mfg says. Heck, half the mfgs nowadays don't even know how to spell CG.
Use the application at the link. Do it for a static margin of 10% and 20% and if you wind up within those measurements, you're good to go. The aft area for it will make the elevator more effective, so compensate by reducing the elevator throw. It's simple logic that works. It's more effective, so move it less, and the airplane feels no different.