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

OS46 best prop?

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Old 05-04-2003, 04:49 PM
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mumblety-peg
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Default OS46 best prop?

What prop should I use for speed on this engine. The airframe is a Laser Arrow.

Thanks
Mitch
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Old 05-04-2003, 10:10 PM
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Default OS46 best prop?

10*8
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Old 05-04-2003, 10:21 PM
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Default OS46 best prop?

Judging from ur sig, it seems u speak from personal experience. So I'm just going to have to listen. Would a tuned pipe make much of a difference or should I save my pennies for hotter engine?
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Old 05-04-2003, 11:39 PM
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Default OS46 best prop?

I have a years worth of experience with the Shrike.

I have asked the same question, it depends on the plane. I would like to get a real hot engine for my shrike (Jett 50) but 250 is a bit pricey. So I have my 46FX stock and she moves, the LHS says a pipe will run me 70 bucks US, so I'm thinking yet, but probably no tuned pipe unless I find a cheap one on Ebay.

What Plane r u using, and what kind of performance do u want???
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Old 05-04-2003, 11:40 PM
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Stingray42
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Default OS46 best prop?

sorry didn't see, u are using a laser arrow sorry.

Should be just like a Shrike, what kind of performance do you want???
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Old 05-04-2003, 11:43 PM
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Default OS46 best prop?

Again...

I have been told a pipe will pull another 1500 rpm.
" " a tower muffler will net some gains too.
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Old 05-05-2003, 12:04 AM
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daven
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Default OS46 best prop?

IMO,

I would suggest the following props for the .46fx.

APC 9 1/2" x 7 1/2
APC 9x7
APC 10x7

A 10x8 sounds a little big to me, the .46fx likes the rpms. Let it turn.
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Old 05-05-2003, 12:05 AM
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Default OS46 best prop?

I would go for the pipe set up if you plan on using that engine for a while. Even if you decide to get another engine for it you will always have a pipe setup for your 46. It is a good thing to have to gain some extra power and rpm's
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Old 05-05-2003, 12:07 AM
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Default OS46 best prop?

Yep... 9x7 would be my guess too.... for starters...

Maybe a 9x8...
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Old 05-05-2003, 01:16 AM
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Default OS46 best prop?

I'm using a 9*7 APC right now. I'm thinkin' I have more thrust than I can use.

I've done a bit of flying with fast small electrics. For a pylon or fast small delta we use "square" props. That is 5*5, 4.7*4.7. But the airframes are very slick.

So if the FX likes to rev up would something like an 8*8 work? Can I buy an 8*8?
If I do use a smaller prop would I have enough thrust to launch and enough thrust for the somewhat thick wing?

I've heard good things about the Tower muffler. Maybe I'll give that a try.

I want more speed, the climb rate is more than enough.
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Old 05-05-2003, 07:38 AM
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Default OS46 best prop?

An 8x8 prop is much too small for the .46 FX IMO...

According to the OS website this engine puts out 1.6 hp at 16000 rpm at best.
If I enter these values in Thrust HP a 9x8 prop is what comes out best.
When using an 8" prop you would have to step up to 13" pitch to absorb 1.6 hp.
Maybe you could even use a 9x9 if you pipe the engines and take into consideration the engines will unload when the plane speeds up once airborne.

Now I know Thrust HP are just numbers, and they are often wrong, but they do provide a good starting point most of the time.

Also, you would have a hard time launching that plane with an 8x8 doing only 15 or 16 K rpm...
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Old 05-05-2003, 02:42 PM
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Default OS46 best prop?

APC makes some pylon props that can be run on a sport plane, but they take some getting use to. The planes take a little time to get up to take off speed, but if you keep them on the ground for a bit, they work fine. Here are some other props that I use for top speed, but not necessarily the best for overall sport flying.

APC 8 3/4" x 8.5 W
APC 8.8 x 8.5
APC 8.75 x 8.75 W

These will take the .46fx between 15,000 and 15,500 RPMs, where I think this motor likes to be run. This is with the Stock muffler, baffle removed, and Omega 15% Nitro fuel.

We use this engine for one of our local racing classes, so we have prenty much dialed it into the props I have listed in my two posts. The props in the first post, will be a little more user friendly, but these should be slightly faster. I'm not overly familiar with your plane, and that will probably have an effect on which of the above props will work best, but these props will get you in the ball park.
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Old 05-06-2003, 12:49 AM
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Default OS46 best prop?

Daven-

Thanks very much for the good info.

Keep it on the ground? Oh-Oh, no wheels on a Laser. It's a fairly thick Delta wing.

But I'm going to try one of the suggested square props. I've got waaayyy more thrust then I need on this plane. And changing props is ez enough.
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Old 05-06-2003, 01:38 AM
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Default OS46 best prop?

Without gear, I would be hesitant with the props in my second post for a hand launch. You may be ok if the plane is very light (under 3 1/2 pounds).

How about a dolly?
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Old 05-06-2003, 01:46 AM
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Default OS46 best prop?

It's just about 3.5 pounds. I think I'm going to stick with the sport props for this one. This is starting to sound like work.

Besides, I've got a Dimond Dust on the way.

Again, thanks for the help. It.... helped
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Old 05-06-2003, 03:08 AM
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Default huh

How about a 9x9? The OS could handle it couldn't it?

I have run my YS-45 on a 9x9 but a 10x7 was better on my fat Lanier F-4
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