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P-51 4 blade prop?

Old 12-10-2004, 07:26 PM
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ScienceisCool
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Default P-51 4 blade prop?

Why does no one use a 4 bladed prop for their P-51's?
Old 12-10-2004, 10:13 PM
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Default RE: P-51 4 blade prop?

I would guess that, because of our direct drive engines, a 4-blade that the engine will be able to swing would look ridiculously small.
Old 12-11-2004, 02:33 AM
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Default RE: P-51 4 blade prop?

Some of us do..
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Old 12-12-2004, 07:25 PM
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Default RE: P-51 4 blade prop?

Cool! I love the way that looks. what kind of engine do you have?

Anyone else have pics of a 4-bladed p-51?
Old 12-13-2004, 04:28 PM
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Default RE: P-51 4 blade prop?

Pelle is right, you will have something that looks like blender blades on the spinner unless you can get a reduction drive.

My guess is that nony's P-51 is a Byron with their prop drive that looks cool from the left side, but on the right side the engine hangs out in the breeze. Check out www.warbirdpropdrives.com for a possible in cowl install.
Old 12-13-2004, 08:37 PM
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Default RE: P-51 4 blade prop?

I tried a four bladed prop on my 46 size WM P-51 with an OS 46 FX. The performance loss was noticeable, but not drastic. The small prop really looked out of place even on this small size plane.

Brian
Old 12-13-2004, 10:52 PM
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Default RE: P-51 4 blade prop?

It takes more power to turn the same size 4 blade than it does a 2 blade. That is why you will drop 2 inches in diameter and sometimes pitch too to compensate. The end result in scale planes is that you have a small 4 blade prob when compared scalewise than a 2 bladed prop.
For example in the 60 size top-flite p-51. The full scale has about a 134 inch prop, divide by 7 equals 19.14 inch. That means you need an 19 inch 4 bladed prop on a 60 size plane. That would take a moki 2.1 or a zdz 40 in a plane that calls for a 61 to 90 twostroke even if you could fit them in they would tear the plane to pieces. I did hear of an rcs 140 in one though which would get you closer. The rcv 120 four strokes can turn large props but still, with the 15 inch maximum, not scale size. If you stick a ys 120 on it then your max prop is a 16x10 2 blade, you might get away with a 15x6 4 blade but no speed. No matter what, the prop will look tiny compared to scale, When the engine is running the 2 bladed prop looks closer to scale as it has a greater diameter and you cant see how many blades you have, just how big the spinning disc is. It then boils down to choice, be like a lot of guys and convince yourself that just having a multi-bladed prop makes it more scale or get as big a diameter 2 blade and think it looks better in the air. I have seen small 60 size p-51's with 10 inch 4 bladed props when the scale size would be about 20 inch, they look silly and the props also don't have the width either.
I don't know which side I am on but I have planes both ways and I will try to get the multi blade if I can and it is close like my little stuka with a 15x6 3 blade on a ys91. My Clarke Spitfire has a 26x12 3 blade prop from the factory which is neither here nor there. To be scale it would need a 36 inch four blader which may come out one day if the gear system happens but till then the 3 blades fools us a little and just makes us pilots feel a bit better. I have the Byron P-51 with the reduction gear and it looks better than anything else out there but it is still about 2 inches too small, it should be 26 inches, its low rpm and the wide blades fool us more than most though. It is very scale in its power availability, some say marginal and some say underpowered. Have fun and just experiment, if you want to look good, get a nice scale static prop for display and stick a big two blader on to fly.
Good Luck
Paul
Old 12-13-2004, 11:58 PM
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Default RE: P-51 4 blade prop?

Here's my 18x12 Zinger 4 blade on my RCV-120 equipped TF P-51 (camera didn't like the red too much[]). It has one flight on this prop at a bit over 11 lbs. I thought it flew pretty scale like, but I didn't put it through too many manuvers. I folded the gear on landing when I slowed it down a bit too much about 2 1/2 feet off the ground and was hessitant to give it much throttle for fear of torque rolling it into the ground (it didn't have that tendancy in the air, just hear horror stories). I have since put it back together and moved some stuff around and lightened it by 12 oz., so hopefully, the next flight will be more successful!

To me, the big prop is part of the beauty of warbirds and I would have a hard time with anything much smaller, although I do have a 15.5x12 4 blade APC to try out also.
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Old 12-14-2004, 01:24 AM
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Default RE: P-51 4 blade prop?

What RPM are you turning on the RCV, they reccomend the 15.5X12 4 blade and no wood so I am wondering how the engine is handling the load. I would be interested to hear as I often consider the RCV for my smaller planes but wasnt tempted yet. The reccomended 15 inch prop just wassn't worth the effort but if the engine can handle the load who knows.
Thanks
PaulIt would work nice for a small Hurricane with a 19 inch 3 blader.
Thanks
Paul
Old 12-14-2004, 01:49 AM
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crownvic
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Default RE: P-51 4 blade prop?

Hybridvw see you are from Graham use to live out there off of 224 .I am now in mc cleary.DO you fly out at the rainer club


MERRY CHRISTMAS

Lonnie
Old 12-14-2004, 10:22 AM
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HybridVW
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Default RE: P-51 4 blade prop?

ORIGINAL: dragoonpvw

What RPM are you turning on the RCV, they reccomend the 15.5X12 4 blade and no wood so I am wondering how the engine is handling the load. I would be interested to hear as I often consider the RCV for my smaller planes but wasnt tempted yet. The reccomended 15 inch prop just wassn't worth the effort but if the engine can handle the load who knows.
Thanks
PaulIt would work nice for a small Hurricane with a 19 inch 3 blader.
Thanks
Paul
Sat. when I fired it up for the first time since I folded the gear, it turned 4000 rpm without tweaking the mixture, I believe when I flew it it turned 4400-4600, but that was over a year ago- it was about 200 rpm shy of what RCV predicted it would be. I didn't get to tune it on Sat. because when I started to actually tune it (after taxiing around the driveway), the barrel nut (part of the prop shaft extention) sheared and the prop flew 70+ feet across my front yard[X(]. I'm working on a TF Corsair now and am hoping to run a 19" 3 blade, but I'm sure an 18" would be fine. I'm sure this isn't the best prop for performance, but it looks good and so far, seems to do fine flying the plane (from the one flight I have on it).

see you are from Graham use to live out there off of 224 .I am now in mc cleary.DO you fly out at the rainer club
I've never flown at any of the local clubs. I grew up on the Kapowsin airport, so that's where I fly
Old 12-14-2004, 05:18 PM
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Default RE: P-51 4 blade prop?

Why not go electric?
Mine flyes beautiful on its 15,2 x 10,5 4 bl- varioprop. 7350 rpm and 7,5 kg trust.
I dont belive it would need (the possible) more trust from th 18,5X12 this motor could turn.
I do belive this looks much better though.

Greetings
flo
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Old 12-16-2004, 03:00 PM
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HybridVW
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Default RE: P-51 4 blade prop?

ORIGINAL: flo

Why not go electric?
How can you have a warbird that doesn't leak oil?!?!?!
Old 12-16-2004, 05:20 PM
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Default RE: P-51 4 blade prop?

ORIGINAL: HybridVW

ORIGINAL: dragoonpvw

What RPM are you turning on the RCV, they reccomend the 15.5X12 4 blade and no wood so I am wondering how the engine is handling the load. I would be interested to hear as I often consider the RCV for my smaller planes but wasnt tempted yet. The reccomended 15 inch prop just wassn't worth the effort but if the engine can handle the load who knows.
Thanks
PaulIt would work nice for a small Hurricane with a 19 inch 3 blader.
Thanks
Paul
Sat. when I fired it up for the first time since I folded the gear, it turned 4000 rpm without tweaking the mixture, I believe when I flew it it turned 4400-4600, but that was over a year ago- it was about 200 rpm shy of what RCV predicted it would be. I didn't get to tune it on Sat. because when I started to actually tune it (after taxiing around the driveway), the barrel nut (part of the prop shaft extention) sheared and the prop flew 70+ feet across my front yard[X(]. I'm working on a TF Corsair now and am hoping to run a 19" 3 blade, but I'm sure an 18" would be fine. I'm sure this isn't the best prop for performance, but it looks good and so far, seems to do fine flying the plane (from the one flight I have on it).

see you are from Graham use to live out there off of 224 .I am now in mc cleary.DO you fly out at the rainer club
I've never flown at any of the local clubs. I grew up on the Kapowsin airport, so that's where I fly
You going to put "what" in your TF corsair? Not the rcv120 I would think. Biggest would be the rcv90 and there, the 15" 3 blade is what's called for.

What are u putting in the TF ?
Old 12-16-2004, 05:21 PM
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Default RE: P-51 4 blade prop?

The 90 could handle a 19" two blade but my concern then would be whether there would be enough ground clearance. Thoughts on that?
Old 12-16-2004, 10:58 PM
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Default RE: P-51 4 blade prop?

Hi All

I've been working on a 20" carbon scale 109F/G blade system for my 80" composite 109. I see from the above post that you guys are turning 4 blades with an RCV 120. I just purchased an RCV 120, maybe I'll try running my blades on that instead of my OS 108 geared down to 1:71 to 1. Power on the 108 rated at 3hp and on the 120 at 1.89hp. I'll just try it.

Personally, I really would like to fly with a scale 3 blade, turning at 4500-5500 rpm, one will see the 3 blades in flight.
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Old 12-18-2004, 09:58 PM
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Default RE: P-51 4 blade prop?

I think the 1.08 will be your best option, a 20" two blade is nearly (if not the) biggest sice RCV recommends for the 1.20. Here's something to think about: HP=Torque*RPM/5252, so Torque=HP*5252/RPM. So the 1.08 has a max rev of 16,000 RPM, we'll say that it makes peak power at 15,000, for good measure. That gives us 3hp*5252/15,000=1.0504 Lb.Ft. of torque. Add in your 1.71:1 gear reduction, and you get 1.796 Lb.Ft. of torque at the prop (ignoring and losses through the reduction unit) at approx. 8775 RPM.

With the RCV, things are a bit different because I'm not sure exactly how to calculate the Tq. because of the internal gear reduction, so follow me and see if this seems correct. Max revs. on the RCV are 6000, but they don't recommend running them faster than 5500, so we'll assume that the peak HP (of 1.89) is at 5500 (prop) RPM. I think that figure is a crankshaft number, since if it was a prop shaft number, that would make the RCV 1.20 nearly a 4 HP motor, which I think is a bit high. So, we have 1.89hp*5252/11,000 (due to the internal reduction)=.9023 Lb.Ft. of Torque at the crank, add in the 2:1 reduction, and you have 1.805 Lb.Ft. of torque at the prop at 5500 RPM.

Since you would like to spin your 20" prop between 4500-5500, I would run the 1.08 with a 2.5:1 reduction to get 2.626 Lb.Ft. at 6000 RPM. Now, there are a bunch of assumptions in my calculations, but since we only have a peak HP and RPM number to work with, it's the best I can do

Voyager, with my Corsair, I would like to try to run as close to scale size prop as I can, and I haven't decided on an engine size yet. That will probably come down to how much weight I need in the nose (the P-51 came out quite nose heavy)
Old 12-18-2004, 11:00 PM
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Default RE: P-51 4 blade prop?

I would too but scale size only comes with using the 2 blader-->19 3/8ths is scale. Can't do that with 3. I'm still concerned with ground clearance with the 2 blade scale though.
Old 12-19-2004, 07:07 AM
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Default RE: P-51 4 blade prop?

Just go to www.psk560.com and scroll dow to "10/30/04 Warbirds over SC"
You can see a video of a Byron Mustang with a huge 4 blade prop.
--
Merlin65
Old 12-20-2004, 06:08 AM
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flo
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Default RE: P-51 4 blade prop?

@HybridVW
Sorry i could not answer earlyer cause i just finished moving house.
Well, how`s about painting oilstains? wouldn`t need cleaning also could be matched to the real thing, not just dirt that comes out of a silencer somewhere in a model. I prefer oilstains in the right places if i build a plane that leaks oil.

greetings from munich
flo
Old 01-14-2022, 06:52 PM
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I an looking for a 4 bladed prop for my RCV .60 p=51 royal kit should be close to 14.5 X 11 4 bladed wood or black plastic .
Old 01-15-2022, 05:16 AM
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I'm building a Hanger 9 that will fly with a 23.6 inch 4 blade varioprop.

I modified my engine just to make sure it had the power to spin it.



varioPROP for the varioprop. Its best, when ordering, to Contact Christian via email.

The engine is a zenoah G62, its been tuned and modified by Performance Unlimited. Its been converted to cdi, timing was changed from 9 degrees tdc to 15 degrees tdc to use all the effective stroke. Stroke was lengthened by 1 mm, bearings upgraded and spring starter shaft has been machined off.



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Old 01-15-2022, 05:24 AM
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Originally Posted by breezebuilt View Post
I an looking for a 4 bladed prop for my RCV .60 p=51 royal kit should be close to 14.5 X 11 4 bladed wood or black plastic .
Chrisyian ramoser makes varioprops of all sizes. Ground adjustable, variable pitch.
something to remember. The varioprop when hooked to an electric motor maxes at 7200 rpm. Don't let it go over.
on gas or glow, max rpm is maxes at 6400 rpm.
both of these are unloaded rpm (in flight)

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