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Old Mar 17, 2010, 09:17 AM
FLY FAST FLY HIGH
WhiskeyJake's Avatar
United States, FL, Florahome
Joined Feb 2009
3,931 Posts
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20cc Gas VS. 1.25 Nitro

My dilemma is a:
I have a Hanger9 Corsair:
Wing Span: 65.25 in (165.7 cm)
Overall Length: 48.25 in (122.6 cm)
Wing Area: 752 sq in (4851.6 cm²)
Flying Weight: 7.5 - 8.5 lb (3.4 - 3.9 kg)
Engine Size: .61 - 1.00 2-stroke; .82 - 1.00 4-stroke

I also have a RCFG 20CC Gas:
Weight - with ignition and muffler
38.1 ounces (1080g)

The Saito 1.25 comes in @
Engine with muffler and header 24.9 oz (706 grams)

Is the weight difference going to make this plane hard to fly or should I look at something bigger for the Gas engine I have.

I have been on the Hanger9 thread for awhile but no one as yet has made this build that I can find.
I really want to go gas but not destroy a plane by putting something too big or have control problems.

Any advice would be appreaciated.

Thanks
JT
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Old Mar 17, 2010, 04:32 PM
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earlwb's Avatar
USA, TX, Grapevine
Joined Dec 2008
13,361 Posts
One problem with radial engine scale planes is having to add useless lead weight to the front end to get it to balance. The engine was most of the weight in the real planes so they had short noses to get the CG back to the rear more. So with the gasoline engine you have more weight up front, so you won't have to figure out how to cram all the servos all the way up forward and still add lead to the front to get it to balance.
I have had to always add several ounces of lead to the front of a radial engine scale plane in the past, so I don't see a problem using the gas engine at all.
Even in the worst case, you might have to add a little lead to the tail, but not likely.

Saito engines are amazingly light, a OS 1.20 weighs about 950 grams or so. So going with the OS 1.20 engine wouldn't be all much less weight up front than using the gasoline engine you mentioned. A 4 cycle 20cc glow engine develops about the same power as a 20cc gasoline two cycle engine.
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Old Mar 19, 2010, 04:46 PM
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Joined Dec 2008
293 Posts
adding to the previous comments.

Gasoline is also cleaner to burn (less slime on plane) cheaper and easier to get a hold of when you wanna fly.
And I may get flamed for this but seems easier to tune and more reliable (at least with electronic ignition)
The extra weight up front issue should be a non issue if you have the engine and the plane. I would say tie or rubber band or tape the engine in plance (i personally use a spot or two of CA to hold engine in place) and see how the plane balances with the engine you already apparently own. Tape the servos and what have you in place and see how it goes. I think you will be pleasantly surprised.

Sean
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Old Mar 20, 2010, 12:38 PM
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United States, MI, Frankenmuth
Joined Jul 2007
82 Posts
Yeah its all about balance. The 20 cc should fly it fine with a high pitch prop to get some speed. The 48.25" length is the only worry I would have. if you do have to add weight to the tail it's nice to have a longer one to work with. Trya a test balance like ONERCBOATER said.-BW
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