Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

MVVS GRRT- 40 F3D on Patriot?

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Old 02-14-2003, 07:00 PM
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Razor-RCU
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Default MVVS GRRT- 40 F3D on Patriot?

I know this motor is for pylon racing but would it pull my Patriot around?

I got one on E-bay (not necessarily for the Patriot but...) was wondering is this combo would be feasible-

Do these racing engines idle at all or is that a stupid question?

I might just try to trade it if it is not suitable-

Thanks in advance,
james
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Old 02-14-2003, 07:36 PM
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FlooredCOBRA
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Default MVVS GRRT- 40 F3D on Patriot?

I have the same engine but mine has the round exit on the exhaust. It does idle though pretty well to slow down for landings. But I know for my engine it took a 7.2 X 8.6 or 7.4 X 8 to get on the pipe. I also tried a 8 X 6 and that worked also but ai did have to shave the tips off some. This engine needs to rev to get the power to come on.

That was the only way I could get it on the pipe. Under the pipe it ran just like a regular sport engine and was not very impressive. But when the pipe kicks it you can tell what separates the sport engines from the racing engines. It is a total different ball game.

Also it is a huge gas guzzler. I can run a 6 oz. tank in 2 1/2 min max on pipe. Off the pipe it runs a bit longer.
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Old 02-14-2003, 07:36 PM
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Flyboy Dave
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Default To Razor....

....does it have a throttle on it....I can't see in the picture
to well. That sucker autta' haul the mail....

I was thinking if you can't get that thing idled down....
it'll come in like a cat with it's tail on fire...

Rev on my Brother.
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Old 02-14-2003, 07:40 PM
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Default MVVS GRRT- 40 F3D on Patriot?

it looks like the same carb set up I have on mine. I can barley see the mounting bracket on the picture.

well at least think thats what it is
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Old 02-14-2003, 07:43 PM
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Default Good question Dave!

I think I can see it on the needle valve side-

hey Cobra thanks for the info. This one does have the round exhaust exit... (what did you fly with this?)

Provided it has a THROTTLE, will my Patriot handle this motor or do I need to get a Quickie 500 to mess with?

james

**BTW** I do not have the engine yet, I just won the auction yesterday- What is it worth if its in good condition? (Wonder If I got gypped...)

Supposedly it was Walter Morris (Morris hobbies..) personal motor-
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Old 02-14-2003, 07:48 PM
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Flyboy Dave
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Default Yo, James....

Sure....it will handle it....but will the pipe clear the
wing....
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Old 02-14-2003, 09:07 PM
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Default MVVS GRRT- 40 F3D on Patriot?

Razor

Looks like the one you have lists for $149.95 without pipe and pipe adapter.

http://morrishobbies.com/product_inf...roducts_id=552

I put my GRRT in my Diamond Dust and it really hauls! Seemed to be a good combo with the dust being so light.
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Old 02-15-2003, 12:41 AM
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Default MVVS GRRT- 40 F3D on Patriot?

From that second picture you posted, you can see the throttle, arm coming off the carb, so yes, it is throttled. I have one with this setup. They throttle pretty well and idle descent considering they are designed to run WOT all the time; it does take a little bit to get the mixtures set right though. The carb they usually put on those have 9mm bores, while the stock venturi they come with are 11mm, so there is probably a slight power loss. (I have the venturi that came with it too, but have never used it.) These engines HAUL! I paid about $225 for my setup with the engine/pipe/carb combo brand new. That should give you an idea what yours is worth. Hope you enjoy your GRRT!

Carl
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Old 02-15-2003, 11:11 AM
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Default MVVS GRRT- 40 F3D on Patriot?

i got my GRRT for........... 15 LOL ah haaaaaaaaahahahah and yes it still has compression and can make my ears ring after a quick test run.
i have both a 9mm carb and the venturi, and a useless 7mm ( why??? ) which i'll drill out to a 10mm sometime
now i just gotta mod a Magnum for it. i got a 8x8 prop because thats all the LHS had, i might be able to get a 7x9 but the exotic sizes aren't easy to come by around here.
whats the magic RPM i should be hitting to get it where it wants to be?
Can a lighter more aerodynamic Magnum with a high reving but less powerful GRRT on a 8x8, beat a West 50 Magnum with the pipe dragging it down and turning a bit slower on a 8x9? watch this space.
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Old 02-16-2003, 06:50 AM
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Default MVVS GRRT- 40 F3D on Patriot?

Im sure it will be fast but there may not be enough thrust. (like a car always on high gear too soon). Therefore on high angle, it can loose alot of speed. To compensate for this is to ensure that your Patriot is kept light. alot of Q-40/q500 Pylon planes are weigh under 4.5lbs.

Using a prop at least 9'' turning at least 15000 would be reasonable.
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Old 02-16-2003, 10:33 AM
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Default MVVS GRRT- 40 F3D on Patriot?

Phillybaby,

Here's something for you to consider when running the GRRT .40 FAI engine. I have two of them and have many experiences with them to recommend you. But it's up to you...

First of... this engine was designed for Pylon Racing and it is tuned for high RPM around the 30,000 range while it's in the air. Therefore, a proper props selection is a MUST. The recommended props should be in these range, 7.5x7 to 7.5x7.5 carbon or wood prop. Anything higher would load up the engine. Although, I have been running the 8x7 with good result. I would not recommend loading this engine under 21,000 RPM on the ground if you use the 8x7 prop because the engine will NOT come on the pipe. If you do it will cause over heating problems due to too much load. However, if you're using the recommended props, you should expect the RPM range above 23,000+ on the ground. Also, use a cold plug and a bladder tank for best result.

There's one other thing you might want to consider... depending on your airplane weight and aerodynamic cleanness, you might want to run a lesser load prop so the engine can unload. If the plane is about 3.5-4lb and it's clean in aerodynamic then you can run the 8x7. But if it's not you might want to consider running with an 7.5x7 or 8x6 as a compromise. Also, in term of thrust, you don't have to worry about it if your plane weight less than 4lb. It will take it straight up into the sky and increases in speed while doing so.

For your safety, I highly recommend using carbon or custom wood prop. A Sport prop is a NO NO and will through blade on you at high RPM. Hope this help.

Sam
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Old 02-16-2003, 11:03 AM
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Default MVVS GRRT- 40 F3D on Patriot?

previously before i had it the engine was used on my own design DD which can be seen on my site, it started on a 8x9, but those used to break back then and so was swapped for a 8x10. i have no idea what RPM it was but it was only on the black mini pipe, i have a full pipe here but i don't think its the proper one as it doesn't just slip over the exhaust and has no ring for the retention clip.

for the time being i'll also be using the 9mm carb, i did test this on a 5 bladed DF fan for a OS 46+ which was all i had to test it at the time, i couldn't hold full throttle for long because the RPM and noise scared the **** outta me and it was trying to escape the clamp mount. ( a DF quickie was the original intention for this engine ) i was told this fan had to be over 17,6k, i think i was quite a few K over that!

getting anything but standard APC or MA props down here isn't easy, we don't have the same racing as in the US hence no variation in props. but i'll see what i can find.
the plane will be a Magnum which because of this engine will be as clean as i can get it, hence very clean the GRRT feels lighter than a West 50 so 3.5lbs should be doable.
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Old 02-16-2003, 06:25 PM
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Default MVVS GRRT- 40 F3D on Patriot?

patriot weighs more than 5lbs, at the most 6lbs
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Old 02-17-2003, 01:51 AM
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Default MVVS GRRT- 40 F3D on Patriot?

I think you are going to have a tricky time getting in air if the weight is 6 lbs. The GRRT is meant to spin a small prop at high rpm with pitch. What I mean by small is a shaved 8 inch or 7 half inch prop.

These will spin high rpm and fly very fast but the thrust on ground may be an issue for your type of plane. It may require a larger diameter prop. But then again if you go larger prop the engine my never even get on the pipe and you will never be able to use the power the engine can put out. It will be a bit tricky find the right prop for your type of plane that will get on pipe and have enough ground thrust to get you in air.

Just experiment and you may be able to come up with something. Also remember this engine is a bit finicky to tune and get set right. Just patience and you will be rewarded with a plane that will haul!
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Old 02-17-2003, 02:07 AM
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Default Yup-

I did not get the GRRT with the intent of putting it on a Patriot, because of the facts listed above (weight, drag, take off roll etc..)

But it might be fun to try I will probably just stuff my YS-45 in it and save the GRRT for a Quickie type plane-

The deal was just too good to pass up-

Thanks for all the info. folks!
james
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Old 02-17-2003, 03:36 AM
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Default MVVS GRRT- 40 F3D on Patriot?

well you can always do what I did and put it in a DD and burn holes in the sky!
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