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Dig it · 12-12-2004, 05:22 PM

I got a old Byron SU-26M off a fellow the other day and loaded it up for flight today. I balanced it and what not and went for the first flight with the cowl off (I usually do just because you never know how much or what you may have to adjust) It flew fine but when I brought it in for a landing, hooooooly was it nuts. Just crazy sensative, a real handfull at low speeds. So, I figured I'd put the cowl back on and give it another go before doing more research on why it was flying like that and wala, it flew like a dream and actually floats so dam far now that I have to force it down. I never realized how much the cowl meant to a plane aerodynamically. Go figure.

Anyway, just some info for people if they have a similar situation.

nony · 12-12-2004, 05:30 PM

just a guess, but probably the turbulence off the firewall affected the inner part of the wing...like the bow wave on a boat......

ronm · 12-12-2004, 06:10 PM

It's tail heavy without the cowl.
If you want to fly it without the cowl, ad nose-weight, it should fly ok then.

It will never fly exactly the same without the cowl for reasons Nony stated.

Dig it · 12-12-2004, 08:36 PM

Nony. Ya, I was thinking the same thing. Amazing how much of a differance it made.

ronm · 12-12-2004, 08:41 PM

If the problem happened at low speed, it was more likely balance than aerodynamics.

David_Moen · 12-12-2004, 10:05 PM

I did the same thing while maidening my 66" Extra. It flew well untill I came in for landing, then the extra drag stopped the thing about 4' off the deck - the remainder of the landing approach was rather vertical.

Dig it · 12-13-2004, 10:05 AM

ronm: I don't think you understand what happened. The problem was fixed when the cowl was put back on, so it wasn't a balance problem, it was an aerodynamic problem. Besides, I just posted this for information for other people so they can avoid the same situation. As the saying goes, don't make mountains out of mole hills.

ronm · 12-13-2004, 11:34 AM

Whatever

craigk · 12-13-2004, 11:49 AM

I agree with Ron - I think without the cowl, you would have been a bit tail heavy,

Dig it · 12-13-2004, 01:12 PM

Well, maybe I'm out to lunch. The cowl can only weigh an oz or 2.

I've flown lots of planes without the cowl, but this is the first time I had run into problems. I see what is being said. The cowl does add weight to the front, I just didn't think it would be enough to cause a CG problem. I have been wrong before.

12-12-2004, 05:22 PM	#1
Dig it RCC Expert Contributor I am: Dale I Join Date: Nov 2003 Location: Red Deer Feedback: 4 / 100% Posts: 841 Total Props: 0	su-26m and cowl Remove this ad - become a site supporter! I got a old Byron SU-26M off a fellow the other day and loaded it up for flight today. I balanced it and what not and went for the first flight with the cowl off (I usually do just because you never know how much or what you may have to adjust) It flew fine but when I brought it in for a landing, hooooooly was it nuts. Just crazy sensative, a real handfull at low speeds. So, I figured I'd put the cowl back on and give it another go before doing more research on why it was flying like that and wala, it flew like a dream and actually floats so dam far now that I have to force it down. I never realized how much the cowl meant to a plane aerodynamically. Go figure. Anyway, just some info for people if they have a similar situation. __________________ Hey Buddy, thats a Kadet not an Extra!!!
	.

12-12-2004, 05:30 PM	#2
nony RCC Supreme Contributor Join Date: Sep 2002 Location: the Park, Ab. Feedback: 0 / 0% Posts: 4,339 Total Props: 0	just a guess, but probably the turbulence off the firewall affected the inner part of the wing...like the bow wave on a boat...... __________________ Wayne The sooner you fall behind, the more time you will have to catch up.
	.

12-12-2004, 06:10 PM	#3
ronm RCC Supreme Contributor I am: Ronm Join Date: Dec 2002 Location: Mission, B.C. Radio of choice: Futaba # of RCs: 10 Feedback: 0 / 0% Posts: 5,625 Total Props: 0	It's tail heavy without the cowl. If you want to fly it without the cowl, ad nose-weight, it should fly ok then. It will never fly exactly the same without the cowl for reasons Nony stated. __________________ Ron Mattiuz Flying Tigers RC Club "Flying an airplane is just like riding a bike...except it's harder to put cards in the spokes"
	.

12-12-2004, 08:36 PM	#4
Dig it RCC Expert Contributor I am: Dale I Join Date: Nov 2003 Location: Red Deer Feedback: 4 / 100% Posts: 841 Total Props: 0	Nony. Ya, I was thinking the same thing. Amazing how much of a differance it made. __________________ Hey Buddy, thats a Kadet not an Extra!!!
	.

12-12-2004, 08:41 PM	#5
ronm RCC Supreme Contributor I am: Ronm Join Date: Dec 2002 Location: Mission, B.C. Radio of choice: Futaba # of RCs: 10 Feedback: 0 / 0% Posts: 5,625 Total Props: 0	If the problem happened at low speed, it was more likely balance than aerodynamics. __________________ Ron Mattiuz Flying Tigers RC Club "Flying an airplane is just like riding a bike...except it's harder to put cards in the spokes"
	.

12-12-2004, 10:05 PM	#6
David_Moen Guest Join Date: Nov 2003 Feedback: 0 / 0% Posts: 280 Total Props: 0	I did the same thing while maidening my 66" Extra. It flew well untill I came in for landing, then the extra drag stopped the thing about 4' off the deck - the remainder of the landing approach was rather vertical.
	.

12-13-2004, 10:05 AM	#7
Dig it RCC Expert Contributor I am: Dale I Join Date: Nov 2003 Location: Red Deer Feedback: 4 / 100% Posts: 841 Total Props: 0	ronm: I don't think you understand what happened. The problem was fixed when the cowl was put back on, so it wasn't a balance problem, it was an aerodynamic problem. Besides, I just posted this for information for other people so they can avoid the same situation. As the saying goes, don't make mountains out of mole hills. __________________ Hey Buddy, thats a Kadet not an Extra!!!
	.

12-13-2004, 11:34 AM	#8
ronm RCC Supreme Contributor I am: Ronm Join Date: Dec 2002 Location: Mission, B.C. Radio of choice: Futaba # of RCs: 10 Feedback: 0 / 0% Posts: 5,625 Total Props: 0	Whatever __________________ Ron Mattiuz Flying Tigers RC Club "Flying an airplane is just like riding a bike...except it's harder to put cards in the spokes"
	.

12-13-2004, 11:49 AM	#9
craigk RCC Supreme Contributor I am: Craig K Join Date: Sep 2002 Location: Sault Ste. Marie Radio of choice: Spectrum NX10 # of RCs: ? Feedback: 4 / 100% Posts: 2,947 Total Props: 10	balance I agree with Ron - I think without the cowl, you would have been a bit tail heavy, __________________ Craig MAAC #9467L IMAC 3706
	.

12-13-2004, 01:12 PM	#10
Dig it RCC Expert Contributor I am: Dale I Join Date: Nov 2003 Location: Red Deer Feedback: 4 / 100% Posts: 841 Total Props: 0	Well, maybe I'm out to lunch. The cowl can only weigh an oz or 2. I've flown lots of planes without the cowl, but this is the first time I had run into problems. I see what is being said. The cowl does add weight to the front, I just didn't think it would be enough to cause a CG problem. I have been wrong before. __________________ Hey Buddy, thats a Kadet not an Extra!!!
	.

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