JohnVH

My Feedback: (38)

Ill have a 20lb plane or so with a G62 in it and I really want to run a 4 blade prop on it. I just dont know what size it will take... Like to hear from those that have done it.

Thanks!

BobH

My Feedback: (2)

John, any 4 bladed prop will not work or produce the desired results. Not direct drive anyway.. You would need to reduce it to produce enough torque to turn a big enough propeller.. A rule of thumb is you go down one prop size for every blade you add sometimes its 2 prop sizes.. so what starts life as a 20 prop ends up being a 16inch.. or less.. as you can see its not practical. Byron made a prop drive system to run their 4 bladed props but they are long out of business. Regards BobH

JohnVH

My Feedback: (38)

So even on a plane that is pretty overpowered like this its not worth it?

So on my G62 I can run a 22x10 normal prop, so I could run a 18x? on it now? That would still pull it wouldnt it?

Anyone out there that is actually flying a 4 blader? They sell them so someone must be buying them???

Thanks!

MikeChilson

My Feedback: (2)

John,

Remember our little engines generally turn much higher RPM's that the big guys in real warbirds. This means the more blades you put on a prop the less efficient. The blades cannot "bite" the air at those high RPM's. The blades is trying to bite the vortex left by the previous blade. This effect gets dramatically worse the more blades you add.

Hope this helps.

JohnVH

My Feedback: (38)

OK, so basically nobody runs a 4 blade prop, and all the props that the Manufacturers make are just for show?

I know that they are less efficient and all that, that was part of my reasoning for the engine that is much larger than it needed to fly..

MikeChilson

My Feedback: (2)

No.... They work fine if you can turn them slow enough... A larger engine has nothing to do with it. The weight trade off to turn a four bladed prop at 3000-4000 rpms with a larger engine would barely get you off the ground.

You need torque not RPM's'

There may be a gear reduction drive unit out there some where but I don't know if anyone makes one anymore.


Later,

Steve Collins

My Feedback: (8)

A friend of mine turns a 14X10 APC fourbladed prop with a YS 1.40. The engine and the plane it is on is far smaller than the one you asked about. This setup is on a Great Planes P-51 and it is easily over 140mph. It is a little faster with a 2 bladed prop.

rcnut43

john.iron bay model company bought out byron r/c.they sell every thing that byron had.phone #304-232-7511 or-mail
them at www.ironbaymodelcompany.com
hope this helps. george

CaptainHook

My Feedback: (80)

Zinger has a 2 blade conversion chart at their web site. www.zingerpropeller.com/_2_blade_.htm

JohnVH

My Feedback: (38)

That chart is great! They would know!!!

20-8 4 blader it is

Anyone else out there running more than two blades?

shupack

john, this is what you need in that bird!

TORQUEMASTER
SPEED REDUCTION UNIT for ZENOAH 62
50% Thrust increase, from 20lbs for standard Z62 to around
30 lbs when fitted with Torquemaster. £154.
1. Bolt-on Unit. no modification to the engine.
2. More torque drives bigger props for increased thrust.
3. Moves the thrust line closer to the centre of the engine.- Easier cowling.
4. Ratio 1.75:1
Thrust - 30 lbs. Weight - 2¾ lbs. Length increase - 2½ in.
Prop shaft is 75 mm above engine shaft. Pulley runs on two ballraces.
Prop .........RPM A well run in engine can give 10% higher RPM.
26 x 8 ......5400 (prop too small. Suggested max RPM - 5100 on prop.
26 x 10 ....5200 (a bit small)
28 x 12 ....4600
28 x 14 ....4400 (takes my 1/3 Camel up vertically!)
30 x 11 ....4000
32 x 12 ....2700 (too big for max power)

http://www.mickreevesmodels.co.uk/
at the bottom of the "other kits" page

alsez

My Feedback: (10)

Have used nothing but 3 blade props on my warbirds over the last 15 years. See Modelairplane News Dec 91. Article on page 53 where my G62 on a 20 -12 -/3 blade blew away the Byron drive and all two blades. AMA - Don Lowe clocked my Corsair the other day at 118 straight and level and 153 out of a dive. The 3 and 4 blades I have are no longer made but I know the Bolly carbon fiber 20 -12 3 blades are still made and they work great.
My new 53# Ziroli B 25 is on G38's with 18-10 three blades and putts along at around 85mph. Al WARD

Wayne22

My Feedback: (2)

My turbine compressor has 16 blades and turns 126,000 RPM . 4 blades turning at 8000 (or so) RPM should not be a problem....It would be a matter of matching the blade to the power that is available.

Zinger makes a fair selection of 4 blades http://www.zingerpropeller.com/4_bladed_propeller.htm

APC does as well.....