is it possible?
 

I didnt want to insult the person who posted the claim, with out knowing for sure myself, so I thought I would ask about this here.
On a general discussion post, someone said his buddy clocked his Great Planes Revolver at 113 mph, on a level pass,three times, with his radar gun. This guy is using a Saito 82 and a 13X8 prop. This airplane should weigh around 7 lbs or so. I have the same plane, but run the O.S. 55 with a 12X7. It weighs about 71/2 wet. By my estimation, I havent seen speeds anywhere near his claims. I think hes full of it. What do you think?

RE: is it possible?
 

If there is a nice "Benjamin" reward for the right answer I would indulge![X(][X(]
But since there isn't I will get some popcorn and enjoy the "Techno Answer's Challenge" one more time![:o]
Embellishing one's speed is like listening to a fish story. That was huge! You should have been there scenario![:-]
Just drop a Jett in your's and go kick his butt![sm=thumbup.gif][sm=thumbup.gif][sm=thumbup.gif]
Relatively speaking of course!
SJ:D

RE: is it possible?
 

Yes, possible...

RE: is it possible?
 

Thats what I would do :D

RE: is it possible?
 

Sounds a little fast to me. Maybe level flight out of a dive. Tailwind maybe?

RE: is it possible?
 

Saito 82a with a 13X8 APC prop on 20/20 fuel should turn 9700 rpm = 74.5 mph true pitch speed on the ground.
Thats a lot of unloading in the air to hit 113 mph. I have my doubts. I had two Saito 82a, not for my type of flying & too thirsty, it was a good day when I sold them :D

If you are running the stock or a pitts muffler on your OS 55 you have a lot of un-tapped power left.
A Macs tuned pipe is the best. Or use a Jett or Ultrathrust muffler to keep it simple. 11X7 APC 14000rpm = 92.8 mph true pitch speed on the ground (and unloads well).
I think that 12X7 is too much for the 55. If you think you still need the 12" disc area try a Master Airscrew 12X6 S-2.

RE: is it possible?
 

Freakingfast: the revolver uses a 3.25 in. spinner. Would I lose anything going to an 11 inch diam. prop? In my opinion, there is already an awful lot of the prop hidden inside the spinner itself when I use the 12x7.

RE: is it possible?
 

You could go to a 5" spinner and you would not notice. Most of the work is done at the tips.

RE: is it possible?
 

The bigger question is, how much drag does the plane have? More drag=bigger disc area, less pitch. Less drag= smaller disc area, more pitch....faster plane:D

The plane looks clean so I'm thinking 11X7 Master Airscrew S-2 or 11X7 APC. The Master is less load than the APC and may work better for you.

RE: is it possible?
 

thanx. Ill try the 11X7.

RE: is it possible?
 

I think I'm going to agree with Mike on this one. 113mph sounds a little fast. My rough calc has the saito spinning at the 13x8 at 15k+ to even come close. 113 kph sounds more realistic for that plane and set up.

RE: is it possible?
 

Best combo so far for the OS55 has been with the 11x6 APC and jett-stream muffler. Turns around 14,500-15,000 rpm.

A 12x7 is WAY too big, even for decent aerobatics use. Regardless of the muffler, you want that engine to turn up around 13,500 to 14,000 rpm ground peak to develop real good power. So far, 11x5, 11x6, 12x4, 12x5 seems to work well. The 11x7 is not bad, but definately does not work well with the Jett-Stream installed (pulled rpm down too far).

And if you are looking for just all-out speed on the revolver.... try a 10x7 or 10x8 .... just be patient while it gets up to speed on take-off.

RE: is it possible?
 

I sure wish i had a saito 82 that can turn a 13x8 over 15000rpms. Only way he would hit 113 is if he was flying with 40+mph winds.

RE: is it possible?
 

hey speed junkie how is the popcorn:D

RE: is it possible?
 

Just got done with my first bag of "Orville Redenbaucher's Sweet Kettle Corn"![X(]
My, My, My, the Foo Foo is a flyin'![:-]
Just enjoying the "Fotter"![sm=punching.gif]
What's been up with the "Budedude"?
SJ:D