Extra3D

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I have a NIB MVVS GRRT 40 with tuned pipe wondering if anyone out there is or has ran this engine set-up?

Thanks Extra3D

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SSAN

Extra3D,

I have much experience with that engine. A matter of fact, I destroyed two (2) of them when I had it. One, the rod let go and the other one, the Quickie that I used to fly it with, the wing folded in the air

I can say the least that one engine was pretty good cause I had many flights with it before the Quickie wing gave way. The other just blow apart after about 10 flight into it, but the distributor took care of it right away.

Both engine was ran with 15% nitro and 8x7 APC Prop turning over 22,000 RPM on the ground rich. But oh boy... When you let it unload in the air, watch out, it scream. Hope some of this info. help.

Have fun flying!

Sam S.

Scorpionjack

Sam
I'm sorry but this may sound bad! But you had those engine's prop'ed way to low! 22,000K with an 8 X 7? You sure you don't mean 9 X 7? And if 22K with a 9 X 7 you would see them in the winners circle more.
Nelson's turn in excess of 19+-21K with 8.75 X 7.75
Jett's turn in excess of 19+-21K with 8.75 X 7.75
I'm turning a 8.75 X 7.75 at 19K with a Webra Q-500
I can get 24.5 K from a F1 Engine with a 8.75 X 8

From what I've seen of the MVVS they are excellent motors, but you really need to prop that engine more. You are way below your optimum speed on a Q-500.

jaka

Hello!

Iīm the Swedish importer of MVVS engines and have been and still is competing in pylonracing in Sweden ( Was with the Swedish F3D team to Muncie, USA in-95).
The MVVS GRRT .40 engine is a F3D engine and as such will perform best on 0-5% nitro and Rossi Nr 8 plug ( Best is a Nelson Glow-Bee but those plugs does not fit this engine).
In F3D pylonracing a common propsize is 7,1/2x7" (carbonfiber)and rpm are around 27000-30000 rpm.
We make our own!
So to get the best performance from the MVVS GRRT you should prop it for a rpm at least 25000 rpm.
That vill give you SPEED!!!
Get a carbon prop from Dave Shadel ( even APC works) and try it out !!

Regards!
Jan K
Sweden

SSAN

Jack,

The GRRT .40 with Tuned Pipe is NOT a Quickie engine. It is a FAI F3D Racing motor running alcohol. But I ran it with 15% nitro and the best it do was running with APC 8x7 at the RPM mentioned. But when it unload in the air... watch out!

Sam S.

Scorpionjack

Sam thanks for the Info.

SSAN

Jack,

You're welcome!

By the way... How's Ukie going down there?

Sam S.

Scorpionjack

Sam;
It's flippin Cold! Was ready for Golf season and a Snow storm is coming through tonight. Flew two R/c's in the front Yard last weekend Sudokhoi and a Magic. Winds are just to high right now for sport flying U/C. But if I don't get a break I'll take a Combat U/C up just to break the Winter Cob Web's.
Q-500 starts in 3 weeks so I have almost 5 ready. Probably will give a beginner one just to keep the new blood flowing.

Take care hope to make it down to the Warm country as this is getting real Old.

Samuel Riippa

Hello
How many slims is needed when I use:
mvvs grrt
Rossi 8
0%nitro
7,1/2x7" prop

Any ideas how to mod needle, this o-ring thing itīs not working .

MMallory

My Feedback: (1)

Samuel,

With 0% you should not need any shims. I would slide a piece of fuel tubing over the needle to keep it from moving.

Mark

jaka

Hallo!
MVVS have a better needle for the GRRT then the one you have....contact me if you want one!
Regards!
Jan K
Airracing
[email protected]
http://hem.passagen.se/airracing