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Big Oakden
06-08-2006, 08:27 PM
Anyone know where I can get 4 bladed props for Electric use in the 15-16" range?

Preferably in an 8 or 10 pitch.

I have seen 4 bladed wood prop systems by Zinger, but not sure if my PJS motor will turn them well enough.

I want that scale look without having to change the props between static display and flying. Plus having to purchase 2 additional aluminum spinners $$$$$$ !!!!!

Oh yeah, on e last thing: I need for standard rotation, and one for counter-rotation. (yes it's a twin)

Am looking for carbon fiber, but will look at anything.

Thanks,

Dave

rcers
06-08-2006, 08:32 PM
Vario is an option. I believe you can mount the blades for couter rotation.

http://www.aircraft-world.com/shopdisplayproducts.asp?id=45&cat=propellers+%2D+VARIOPROP+variable+pitch

APC makes these:
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LX1642&P=7
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LX1639&P=7

What PJS motor are you using? It must be a monster....a 15" 4 blade is like a 17=18" two....

Mike

bsoder
06-08-2006, 08:38 PM
I wish there were more three and four blade options in smaller props... I'd love to see APC E 3/4 blades in the 7"-11" range, with different pitch options.

tahustvedt
06-08-2006, 08:47 PM
To spin a 15-16" diameter 8-10" pitch prop fast enough to have a good top speed you'll need at least 850 W per motor while static testing. That's why it's not beneficial to lower the pitch in order to be able to run a large multi-bladed prop. How many RPM do the motors like to turn at with the voltage you're running?

Varioprop make scale-looking 15" props with adjustable pitch, but I'm not sure if those sizes are available as reverse rotation as well. www.ramoser.de (http://www.ramoser.de) www.aircraft-world.com (http://www.aircraft-world.com)

I made a four-bladed 18x12 prop by joining the blades of two 18x12 APCE props with several layers of carbon fiber at the hub. It has worked very well in an aerobatic plane and I will test it in a 1:6 Spitfire soon. The prop is incredibly quiet. I'm using a custom-wound motor and I get 5000 rpm while static testing.

Big Oakden
06-09-2006, 03:06 PM
rcers:
I will be using either a PJS5000 or PJS6000 from visionhobbies.com
pjs5000 with 8 cell Lipo will turn 12K rpm on a 17" prop (407rpm/volt)
pjs6000 with 10 cell Lipo will turn 10.2K rpm on an 18" prop (275rpm/volt)

I want this plane to be as scale as I can afford to make it.
ie: if I could afford it I would put in two PJS8000 or 10000 and swing zinger 4 bladed props, but I have a wife, a house, a car payment, and thus cannot afford a battery payment !!!
the PJS8000 with 10cell Lipo will turn a 20" prop around 9000rpm (244rpm/volt)
the PJS10000 with 10 cell Lipo will turn a 22" prop around 7800rpm (212rpm/volt)
They also have a new one:
PJS18000 with 12 cell Lipo will turn a 36" prop 6660rpm (150rpm/volt)

I have the room to put any of the above in the plane, but not the money for the ESC's and Batteries.

AUW is projected to be around 14-16lbs.
the PJS5000 will give me around 22lbs of thrust(11lbs x 2)
the PJS6000 will give me around 30lbs of thrust(15lbs x 2)

what warbird should not have a 2:1 power to weight ratio????

IF you need anymore info, e-mail me, or Rich at Vision Hobbies.

ps: Can't wait to get this bird in the air!!!!

rcers
06-09-2006, 03:27 PM
What warbird - now I am intrigued!

Mike

Big Oakden
06-13-2006, 08:48 PM
Mike,

when I get closer to being finished, I will post some pics. Until then, you will have to wait. :-(
Only 4 people know what I am building, and that is because he is helping me with the power requirements, (and his two sons-they held open the plans so their Dad could see the plane.)