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.

Just seen the weight of the 3001 servo is 48g, its prob 3 times further back than it would be making it about 150g?

Thats about the weight I needed to add to the front. Maybe I'll move it back again.

Always start from the recommended CG, particularly with a CAP 232. If you have to add nose weight, add nose weight. You'll have plenty of engine to haul a few extra ounces around. A balanced CAP 232 can be nerve wracking to fly (they don't call them SNAP 232's for nothing). A tail heavy CAP would be a short-lived nightmare.

Once you fly it, you can start removing a little weight at a time moving the CG back, but save that for after the first few flights.

Brad

Ok, I have to ask..

What exactly is BFMA "A"??

Hi!

I have the World Mdel Cap 232 with a Saito 72. Presently the c.g. is positioned at 95 mm, which I have found to be a good compromise for my flying style (traditional aerobatics). IMHO the manufacturers value of 83 mm is on the conservative side, 100 mm on the other hand is too far back unless hovering is your only interest ;-).

The WM Cap is one sweet aircraft to fly. It is not ideal for 3D, but flies IMAC style aerobatics very well.

Using my old JR-388s Tx my set-up includes:

15% aileron differential
+12% left rudder to elevator mix (elevators move up with rudder input)
+15% right rudder to elevator mix

The rudder-elevator mix is to correct for the usual tendency of CAPs to tuck towards the belly in knife-edge flight.

I suggest you start with about 2/3 of the recommended elevator throw to start with, i.e., approx +- 25 mm.
Later on, when you get accustomed to the aircraft you can increase the throw. On my aircraft I have set the elevator throw to 30 mm up and 35 mm down in order for the aircraft to perform inverted and upright loops of equal size.

BTW, while the APC 12.25x3.75 (and the 14x4) propeller is good for 3D hovering, IMHO it is about useless for anyting else. With your engine I would try an APC 12x6 or 12x7 propeller in order to increase the level speed, thus facilitating large looping maneuvers.

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.

Look here under test standards
http://www.bmfa.org/achievement/index.html

It's a test to see if you know to perform certain basic maneuvers.

Yes, sorry, I'm in the UK. As part of ou training we need to pass the British Model Flying Association (BMFA) "A" including left and right circuits, figure of eight, dead stick landings etc. All with pre-flight and after flight checks and anser 5 safety questions. Just to make sure people at teh clubs are safe to fly solo. You have to be refeered to an examiner by your instructor.

Back on subject, I flew the CAP today with added weight to get the CofG at 83mm, very stable and no bad tendancies, landed nice too. So happy. The OS55AX seems econimical too, only had 1/2 gallon of contact 10 fuel and still a little hesitant. Was thinking of getting a 4 stroke though, anyone know how an SC70FS would compare to the OS55AX on fuel economy and power? or it it would,even fit in the cowl? Or, any other suggestions for a four stroke or should I stay with the 55AX?

Overall, very pleased with the plane, only tried outsie and inside loops, stall turns and rolls (Rolls very fast and smooth); will try more moves next time, started raining so went home.