Great Planes Gee Bee r2 Questions
08-20-2004, 11:06 AM
#1
Senior Member
Thread Starter
My Feedback: (1)
Join Date: May 2002
Location: airplane town, TN
Posts: 389
Likes: 0
Received 0 Likes
on
0 Posts
Great Planes Gee Bee r2 Questions
Here they are
1.) what prop would/could you swing on this model with a OS 120 four stroke
why? a.) the power is not all that I think it should be
b.) the engine is getting hot as hell
info: I'm swinging a master air screw prop 16/8 and I'm using 15% cool power...keep in mind this motor pulled a Gee Bee Y120 around (more weight) just fine (same fuel mix)
2.) Also' is anyone flying this model (GP Gee Bee r2) with an OS 120 four stroke and having this temperature problem...I'm checking the vent area's around the cowl today...thanks
1.) what prop would/could you swing on this model with a OS 120 four stroke
why? a.) the power is not all that I think it should be
b.) the engine is getting hot as hell
info: I'm swinging a master air screw prop 16/8 and I'm using 15% cool power...keep in mind this motor pulled a Gee Bee Y120 around (more weight) just fine (same fuel mix)
2.) Also' is anyone flying this model (GP Gee Bee r2) with an OS 120 four stroke and having this temperature problem...I'm checking the vent area's around the cowl today...thanks
08-20-2004, 01:18 PM
#2
My Feedback: (90)
Join Date: Dec 2001
Location: Elephant Butte, N.M.
Posts: 6,716
Likes: 0
Received 2 Likes
on
2 Posts
RE: Great Planes Gee Bee r2 Questions
Are you using the "dummy" radial? If not, put it in with only the area in front of the cylinder open. If you have too much air intake, the air cannot get out before heating up. You need at least twice the cooling air exit area as intake, due to expansion of hot air. 3 times would be better.
08-20-2004, 04:09 PM
#3
Senior Member
Thread Starter
My Feedback: (1)
Join Date: May 2002
Location: airplane town, TN
Posts: 389
Likes: 0
Received 0 Likes
on
0 Posts
RE: Great Planes Gee Bee r2 Questions
ok' I hear ya...a friend of mine opened that hole a little more last Saturday and what your saying is we might have made the problem worse...thanks for the input...I don't know where I can cut the cowl on the back side but I'll keep your ratio (3to1) in mind...thanks...
08-20-2004, 05:40 PM
#4
My Feedback: (90)
Join Date: Dec 2001
Location: Elephant Butte, N.M.
Posts: 6,716
Likes: 0
Received 2 Likes
on
2 Posts
RE: Great Planes Gee Bee r2 Questions
If you have a good in / out ratio and still overheating, you may need to put in some diverters or ducts to direct the air over the engine. If that does not work, I would check for some other problem with the engine.
You may be overpropped. Dont worry about the amount of prop out past the cowl, just use a prop that works good. The prop does not need to extend past the cowl diameter, props are tractors, not pushers. They screw through the air. Adrian Page flew his Gee Bee with a prop that was the same diameter as the cowl & fuse to prove it would work.
You may be overpropped. Dont worry about the amount of prop out past the cowl, just use a prop that works good. The prop does not need to extend past the cowl diameter, props are tractors, not pushers. They screw through the air. Adrian Page flew his Gee Bee with a prop that was the same diameter as the cowl & fuse to prove it would work.
08-21-2004, 03:44 PM
#6
Join Date: Dec 2001
Location: Upplands Vasby, SWEDEN
Posts: 7,816
Likes: 0
Received 6 Likes
on
6 Posts
RE: Great Planes Gee Bee r2 Questions
Hi!
First ...You use a too large prop!
You should use a 16x6 (if you fly at sea-level).
For performance get rid of that MA "thing" and get a real prop.... an APC.
I fly my GEE BEE R-2 with a 15cc (.91)MVVS twostroke using a 14x6 APC and it performs real good. I first flew it without having an air intake in the dummy engine and that worked good but for safty I took up small holes in front of the engine and silencer and this worked too (no difference though).
I use 15% synthetic oil from French racing oil manufacturer Motul. Oil is called Motul "Micro".
I also use 5 nitro.
Weight off the GEE BEE is a little under 5kg.
Regards!
Jan K
Sweden
First ...You use a too large prop!
You should use a 16x6 (if you fly at sea-level).
For performance get rid of that MA "thing" and get a real prop.... an APC.
I fly my GEE BEE R-2 with a 15cc (.91)MVVS twostroke using a 14x6 APC and it performs real good. I first flew it without having an air intake in the dummy engine and that worked good but for safty I took up small holes in front of the engine and silencer and this worked too (no difference though).
I use 15% synthetic oil from French racing oil manufacturer Motul. Oil is called Motul "Micro".
I also use 5 nitro.
Weight off the GEE BEE is a little under 5kg.
Regards!
Jan K
Sweden
