CG Super Chipmunk & OS 70 Surpass
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CG Super Chipmunk & OS 70 Surpass
I'm looking very hard for a kit to build this winter, and I have an O.S. 70 Surpass sitting on the shelf waiting for a home.
The specs on the CG Super Chipmunk call for a 45-61 2-cycle, then call out a 90 4-cycle. Tower bundles it as a package deal with a .46.
I would think that my 70 Surpass would haul anything a 45 2-cycle could handle, but I could be wrong especially when it comes to 4-cycles! Thanx taking the time to consider my question. Dzl
The specs on the CG Super Chipmunk call for a 45-61 2-cycle, then call out a 90 4-cycle. Tower bundles it as a package deal with a .46.
I would think that my 70 Surpass would haul anything a 45 2-cycle could handle, but I could be wrong especially when it comes to 4-cycles! Thanx taking the time to consider my question. Dzl
#2
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RE: CG Super Chipmunk & OS 70 Surpass
Nope. A 70 4-stroke is just too small for the Chippy. It really needs a 91
Now if you want something for that OS 70, try a Goldberg Anniversary Cub (Clip the wing) or the Great Planes Ultimate 40.
Both are great kits and both are excellent with a 70 surpass
Now if you want something for that OS 70, try a Goldberg Anniversary Cub (Clip the wing) or the Great Planes Ultimate 40.
Both are great kits and both are excellent with a 70 surpass
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RE: CG Super Chipmunk & OS 70 Surpass
I have the Goldberg Chipmunk with a 91 Surpass and it's great................ BUT a 70 Surpass will be just fine. You wont have the unlimited vertical performance that the 91 gives, but it will still be a great flyer.
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RE: CG Super Chipmunk & OS 70 Surpass
Boy, you guys are quick! Thank you both.
MinnFlyer: I'm not looking for a all-out aerobatic model, just something different from a 4*60 or a Tiger 60. Could Marcol be right about just losing the top end performance leaving a nice Sunday flier? Dzl
MinnFlyer: I'm not looking for a all-out aerobatic model, just something different from a 4*60 or a Tiger 60. Could Marcol be right about just losing the top end performance leaving a nice Sunday flier? Dzl
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RE: CG Super Chipmunk & OS 70 Surpass
Broken Wings: You are right, but I already have a KAOS in my inventory. Thanks for going to the trouble to look up the link and all, though, Dzl
#10
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RE: CG Super Chipmunk & OS 70 Surpass
Depending on the kind of flying you do, the 70 could be just fine. I try to make my planes look and fly like the real ones. I built the Chipmunk with an OS 70 and enjoyed it so much, that when I wore it out, I built another one. The only airplane that I have built two of for myself.
LKes
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RE: CG Super Chipmunk & OS 70 Surpass
Hi Diesel,
I have a Chipmunk with the OS 70. The model came out a little on the heavy side, but flies really well. As Minnflyer says the 90 would be better for all out aerobatics, but I can pull into a half loop and roll out to straight and level from takeoff. I do try and maintain my energy through out my sequence though, I can't just use the throttle to accelerate if I get slow.
I've tried a few different props and settled on an APC 12x8. The take off and initial climb is better with a lower pitch but once I get the nose down and a bit of speed on the engine seems to get into the power band a bit and flies better with 8" pitch, but like I say, I have to manage my energy a bit to stay in the power band. Mind you the last couple of times I've flown the RPM has been better. The engine should nearly be run in as it has over 200 hundred hours on it now. (I'm not kidding, I have an OS 48 with around 250 hours as well, both engines are still getting better each time I fly)
I run zero nitro fuel so there is probably a bit to be gained there.
My model needs some lead to balance with the 70, but as I said, it's a bit heavy anyway, which tends to make it tail heavy.
If I was building another chipmunk I would choose the 90, but it's a great model with the 70 as well, mind you there would be plenty of people that would consider a 120 to be marginal for this model I suppose.
Cheers Dave H.
I have a Chipmunk with the OS 70. The model came out a little on the heavy side, but flies really well. As Minnflyer says the 90 would be better for all out aerobatics, but I can pull into a half loop and roll out to straight and level from takeoff. I do try and maintain my energy through out my sequence though, I can't just use the throttle to accelerate if I get slow.
I've tried a few different props and settled on an APC 12x8. The take off and initial climb is better with a lower pitch but once I get the nose down and a bit of speed on the engine seems to get into the power band a bit and flies better with 8" pitch, but like I say, I have to manage my energy a bit to stay in the power band. Mind you the last couple of times I've flown the RPM has been better. The engine should nearly be run in as it has over 200 hundred hours on it now. (I'm not kidding, I have an OS 48 with around 250 hours as well, both engines are still getting better each time I fly)
I run zero nitro fuel so there is probably a bit to be gained there.
My model needs some lead to balance with the 70, but as I said, it's a bit heavy anyway, which tends to make it tail heavy.
If I was building another chipmunk I would choose the 90, but it's a great model with the 70 as well, mind you there would be plenty of people that would consider a 120 to be marginal for this model I suppose.
Cheers Dave H.
#12
RE: CG Super Chipmunk & OS 70 Surpass
A Saito 82 would be a good choice too. They are incredibly light!! Loads of power... Lighter than the saito 72!! Seriously my Saito 82 is lighter than my 46ax! Waaaay more power! But if yer gona spend that kind of money just go with a saito 115. Similar weight to a 91. more power... I know I'll probably get thrashed for suggesting the bigger engine but I have grown accustom to flying with more power. It's nice to have to get out of trouble. The power difference between a 91 and a 115 is not a scary one. I have a buddy that flew one with a ys120. In fact i watched my buddy fly his gp 40 size cap 232 with a ys120. Most of the flight was at 1/2 throttle. Granted the ys120 is extreme overkill...