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

World Models .40 size P-51 speed question

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Old 07-05-2006, 10:11 AM
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superman65355
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Default World Models .40 size P-51 speed question

I know there is another post concerning the WM P-51, but mine is a little different I already have the motor I'm looking for info on the best prop size and pitch and anything else I can do to wring a little more speed out of it.

WM P-51 Mustang .40 Dago Red w/retracts

O.S. .50 sx / tuned pipe

I am running a stock apc 11x7

now you fellas are sqeezing all the speed you can out of these but im just looking to get all I can from this motor and plane I understand I won't get the speed you are but I want to be able to fly this one as fast as it will, My club is small so I dont have to impress large crowds and I dont race...yet only been flying for 3 months (2 weeks traing thanks to Real Flight) All we do is a little sport flying for the fun of flying.
Thanks In advance for any help.

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Old 07-05-2006, 12:06 PM
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bob27s
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Default RE: World Models .40 size P-51 speed question


ORIGINAL: missouricannonworks

I know there is another post concerning the WM P-51, but mine is a little different I already have the motor I'm looking for info on the best prop size and pitch and anything else I can do to wring a little more speed out of it.

WM P-51 Mustang .40 Dago Red w/retracts

O.S. .50 sx / tuned pipe

I am running a stock apc 11x7

now you fellas are sqeezing all the speed you can out of these but im just looking to get all I can from this motor and plane I understand I won't get the speed you are but I want to be able to fly this one as fast as it will, My club is small so I dont have to impress large crowds and I dont race...yet only been flying for 3 months (2 weeks traing thanks to Real Flight) All we do is a little sport flying for the fun of flying.
Thanks In advance for any help.

Change your prop. Try 10x7 or 10x8, make sure you pipe is tuned properly to match the prop/rpm

The OS50 is an rpm engine ... somewhat high-timed, and responds nicely to the pipe. Try to prop and tune the system to run somewhere around 15,000-16,000 rpm.
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Old 07-05-2006, 06:30 PM
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Cyclic Hardover
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Default RE: World Models .40 size P-51 speed question

Get some pitch on the prop, maybe 10/10 or 10/11
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Old 07-05-2006, 11:56 PM
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superman65355
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Default RE: World Models .40 size P-51 speed question

Well I went out this evening and leaned it out a bit replaced it with a 10x8. when running the 11x7 apc I was getting about 10,500rpm with the 10x8 MAS I got 13,500 I still think this engine will produce higher RPM's I'm new to the tuning scene so will have to try a few different things I have to pick up a couple more props in 10x9-11 and see what she does.
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Old 07-06-2006, 12:35 AM
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Default RE: World Models .40 size P-51 speed question

It certainly sounds like the pipe is not tuned for that APC 11x7. With a good full length tuned pipe at the right header length, running 15% nitro, the OS .50 SX should pull between 13 and 13.6K static with the APC 11x7. With an APC 11x6 or an APC 10x8, again with the pipe length tuned correctly, the OS 50 should do at least 14K.

Jett Engineering's site is a good place to start for info on how to tune a pipe.

Good luck and report back to us your findings.
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Old 07-06-2006, 11:57 AM
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Default RE: World Models .40 size P-51 speed question

The 10X8 should be your prop of choice. When tuned properly it will have a little more pull to combat the poor aerodinamics of the mustang. I run a 50sx on a 9x9 but the 10x8 will pull about the same. Like someone said you probally don't have your header cut to the proper length to gaine the tuned pipe advantage or your low or high needle isn't letting the proper amount of fuel get to the engine. The tuned pipe will require more fuel so open the slow needle up a little and retune. I think I get a little better than that with a Tower muffler on the 9x9.
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Old 07-06-2006, 12:44 PM
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Default RE: World Models .40 size P-51 speed question

The Dago Red has a big fat spinner....a 10" prop will only have "nubs" sticking
out the sides....

Put more motor in the plane and use a 12" prop.

FBD.
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Old 07-06-2006, 07:27 PM
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Default RE: World Models .40 size P-51 speed question

ORIGINAL: Flyboy Dave

The Dago Red has a big fat spinner....a 10" prop will only have "nubs" sticking
out the sides....

Put more motor in the plane and use a 12" prop.

FBD.
Yeeeeeeeeeahhh!!!! Now thats what were taking about mo motah. I run Saito 100 in mine on a 11/11. Anyways, more rpms may not give you the speed your looking for. Your going to have to experiment a bit.

I was looking at your props and rpms numbers here. Your 11/7 gave you 10,500 and the 10/8 gave you 13,500. If it were my setup, I would jump up to a 10/10 or 10/11 and see how it goes. You rpms numbers will fall around the 12's but your speed should increase
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Old 07-09-2006, 02:02 AM
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Default RE: World Models .40 size P-51 speed question

Sorry but Cyclic is WAY off... That engine will not enjoy a 10/10 or 10/11, that is wayyy too much prop. for the SX.

Seriously, the first thing you NEED to do to get speed is use an APC prop. I would get a 10x7 for starters!
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Old 07-09-2006, 02:59 AM
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Default RE: World Models .40 size P-51 speed question

....[X(]....

....how about a real propeller....

FBD.
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Old 07-09-2006, 03:49 AM
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Default RE: World Models .40 size P-51 speed question

I'll 2nd...(or 3rd) the APC 10 X 8

My Dago Red has a Webra .50 with an Ultra Thrust and the above prop and it honks!

How fast do you wanna go?
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Old 07-09-2006, 12:53 PM
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Default RE: World Models .40 size P-51 speed question

ORIGINAL: Razor-RCU

Sorry but Cyclic is WAY off...
Ouch, that hurt!! The whole thing is off. He's got a 50 with an 11/7 getting 10,500? Thats way off. I would expect that up at the altitude I'm at but not their and especially with a pipe. He could propably do better by taking the pipe off.

I fly high pitch props. I don't own the 50 sx but seen enough of them and they're a healthy engine. I'll compromise in the 10/9 area but definitely go APC. It's not a 3d plane, I could care less about unlimited vertical on a speed plane[>:]
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Old 07-09-2006, 01:04 PM
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Default RE: World Models .40 size P-51 speed question

We found out at the Revver's get together that APC's were good for cutting
carne asada....

....thats about it.

( big motor and big prop=big speed )
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