YES i have an Mvvs Q500 .40, and well
i'm have trouble finding a speed prop?
i've tried 7.2x8.6 it dosen't work. well
what about 8.5x6.5,or 8x9,or shaved
8x10? well its on a V-VECTOR.

Did you try a pylon racing prop? 8.8 x whatever.

what does not work about the prop? I am not sure what you mean by not working. Do you mean the plane wont get off the ground or does the engine just run bad or never get on the pipe?

THE 7.2x8.6 DOSEN'T work as a speedprop.

I found that any prop I use has to be shaved to get it to run on pipe. I am not sure how close the Q500 is to the GRRT but thats how i been doing it with mine.

I even used a 8 X 6 shaved down and found it to work really good. That got me in ball park and after that I got an idea what props to use. I flown it with the 8 X6 to get used to it and then tried the 7.2 X 8.6 shaved down. I could not tell a difference speed wise between the 2 . I also tried 7.4 X 8 and I also had to shave it to get up on pipe.

I really could not tell a difference between the props since i had to shave them all. One might have more pitch but after it was shaved the blades where fairly short. It is almost like i gain in on and loose the other. I am wondering if it is even worth going higher pitches since i have to shave off so much to get on pipe. But by then the prop is so small it is like I have not gained anything.

Over all my favorite prop is the 8 X 6. and the 7.4 X 8. more so the 8 X 6

A 7.2" diameter is too small for that engine or the V-Vector IMO. I would use atleast a 8.75" diameter.

From many discussions here I think there is consensus that the Q40 engine and prop is not suited well to the diamond dust, the whiplash or other q500 planes. The thrust is just not there. I have the nelson q40 turning 23500 on the ground and lauching is an experience every time and the top end is limited to about 180. Better selection is the q500 engines, jett50, jett45 ect. You need to turn a 8-9 inch prop.

The engine mentiond in the first post is a MVVS Q500 engine.

Yes but the prop mentioned is a typical q40 prop. The point being you need an 8-9 inch prop to get the performance he is looking for. The engine is a good choice for the plane but as i stated earlier he needs a pylon racing prop ie 8.8 inch diameter.

Easiest thing to do is slap a 9x7 on it and go from there.

i use a 9x6 on my MVVS PSQ with a baffled full pipe

The props i'm going to check into are the APC 8.75x7W, 8.75x8W
8.75x8.5w, and the one that I think that will be the best for speed is the 8.75x9NN,its cause the 8.75x7.75NN has no speed @ all maybe 115mph, but I'll try the 9 pich and see what that does

Depending on how your pipe is tuned, the 8, 8.5 and 9 pitch props might be just too much prop for your MVVS. It would be interesting to see what your motor tachs with a standard 9x6 and 9x7, as suggested by philly and jlong. Those and the 8.75x7, should be in the ball park. I would think you could get 115 mph with a 9x6, since we nearly there in the APRA class Q500 with TT40's.

I know its counterintuitive to suggest less pitch for more speed, but I don't think the 9 pitch prop will help, if the motor is not up on the pipe.

Paul

I GET 18,530RPMS with a 9x6. But its with a "8.75x9NN", wouldn't

you think the NN would make up for the "too much pitch"

problem ? I've clocked my v-vector @ 142mph with a 9x6.

I am not sure what APC's different designations mean on their 8.75 pylon props, except perhaps for variances in blade design. However, I don't think the designation is going to make up for 9 inches of pitch though.

If I follow this right, you got 115 on the 8.75x7.75 and 142 on a 9x6. 142 is pretty darn good, and the 18,500 is respectable. It sounds like the 9x6 might be your prop. Did you try a 9x7?

Paul

Originally on my DD I used the MVVS .40 with Mini pipe and found it worked with 9x6 or 7 APCs. Also ran great with APC 8x8 and was fasted with this prop. Since started using Rossi 40 guickee engine with a pipe, best prop on this engine is still APC 8x8. No comparison between Rossi and Mvvs. Rossi blows MVVS out of the water. Not trying to say Rossi is the best engine but they sure run great and have good power.

Don
MAAC # 7765

On my 40 size F-20 Tiger Shark, I run an APC 8x10 (8 Inch, 10 pitch) Prop on my OS .46FX w/Macs tuned pipe at 14,000rpm. Taking off the ground is a little hard, but the plane does move around good with this setup.

Adrian

LOOK I'm sorry MR.Deadstick Don, but I talked to MR. Robert, down @ Houstin Texas, and the Quicky.40 Beats the Rossi,
9 out of 10, and the airplane he used to come pare was the
V-Vector. An the 9x7 is the power prop, and on my Mvvs Q500
.40 I get 21500, on an 8x5, but I'm making a modifcation on the
engine to get 23,000. but in my opinion, the 8x9,8x10,8.75x8.25,
or the 8.75x9.0!!NN!!, out of the four will br the speed prop.
so after I make all the adjustments on my Vector, its going to bore a hole in the sky.Also yesterday I used a 9x10, i shaved
it down to a 7x10 well it did pretty well, but it still isn't the speed prop. my goal is to get 150mph in level flight, and 208mpn in
a dromatic dive. sorry........the 10x7 is the power prop.its
16,000 @ 2.2hp. So.........MR. pdxpaul, do you think the 9.0NN
will pass the test? well thanx in advance

My quess is that the 8.75x9 will likley be too much prop for your MVVS. As a reference, the Nelson Q500s are turning 8.8x8.75, x9, and x9.25 in the 19,000-19,500 range, depending on local conditions. I believe the Jett Q500 is comparable. The MVVS and Rossi just don't have the power to turn those props with the Nelson and Jett.

Also, I don't know what the ideal rpm's are for the MVVS Q500, but I suspect its in the 17,500 to 18,500 range. I would pick the highest pitch prop, with an 8.75 to 9 inch diameter, that lets the motor turn up in that range. I am not sure the 8 inch and less diameter props help because of the drag of a quickie airframe. Those smaller props work on Q40's and I have used an 8x8 with success on my Diamond Dust, but not sure about a quickie.

But hey, I don't have an MVVS. Put the 9nn on and tach it, and let us know.

Paul

208 mph in dive?

heck why not just round it off to 210 mph in dive...

Well the highest rpms i gottin on my q500 mvvs is 22,300 with a
7x6w. Also my dad has a dd w/ new GRRT, and well he only has a power prop, its swings @ 21-22,000 rpms with a 7.5x7. well his speed prop is an 7.2x8.6. I'm soon goin to put one on my Magnum. right now
I have a magnum .46 w/8x8, with a performance pipe, going @ 126 mph, spinning on the ground @ 18,000rpms. I'd cosider it a jet trainer. kevin

Be careful putting a 7x6 on your MVVS. Use a Q40 prop if you want to turn those RPMs.

Paul

sorry i meant 126mph with a 10x6 airmasterscrew, that prop is very loud, its kinda funny sound , like the prop is hitting pass supersconic. i'm getting 130plus with an 8x8 i have on it right now

well with the magnum it is.

well thats the training engine, the true beast machine is the "MVVS Grrt". With an APC 7.2x8.6

Well I finally tached the 8.75x9NN, what I got was 14,300RPMS,
to me, in my opinion I what I should do is shave the 8.75x9NN,
and make it to an 8x9NN.