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andy120
11-24-2006, 06:16 PM
guys
i anyone able to/actually making scale props for warbirds? im wanting 12" diameter 5 blades for my griffon spitfire.

many thanks
andy

Glacier Girl
11-24-2006, 08:12 PM
Andy it's one of those how much do you want to spend questions you asked. Look at Varo props or Solo props for mulit blade setups, also in most of the modeler mags I've always seen ads for multi bladed versions, like what you're looking for.

hul
11-25-2006, 07:54 AM
Varioprop has 5-blade props. You'll need a fair bit of power and more pitch than normal to reach a reasonable pitch speed tough. 12x12 at 400W would be around 50mph.
http://www.ramoser.de/home_e/varioprop_e/varioprop_e.html

Hans

tahustvedt
11-25-2006, 02:28 PM
I have made a few four and five blade props in the 18-19" range for my 1/6 scale Spitfire XIV. I made the 18" four blade with 12" of pitch by chopping up two 18x12 APCE props and glueing them together with carbon fibre at the hub. I rewound an Axi 4130/20 to 24 turns to spin it at ~5000 rpm which flew the spitfire very nicely and behaved quite similarly to a 20x13 two blade in my Velox aerobat. Later I made a 19" four blade and a five blade with a different technique using . I made aluminium hubs that I fastened APCE halves with two screws on each blade. I'm using these props now in my Spitfire with another motor that I ewound to 29 turns for even more torque. The 17x12 blades are mounted 1" from the center of the hub and this increases both diameter and pitch with a couple of inches.

To spin a multi-bladed big prop at the same power level as a smaller two-blade prop you need a motor with a lot of torque. This means low rpm and low pitch speed, so the prop pitch needs to be very coarse. It's a balancing act. Another problem is finding a spinner that looks right and is made for multi-bladed props, so I have to make my own from fibreglass.


Lately I've been working on a 1/6 scale P-40. I'm using a 20" three blade soloprop on it running at 3800 rpm with a homemade belt drive and an Axi 4130/20 motor and it flies well. I haven't made a spinner for it yet.

cyclops2
11-25-2006, 11:43 PM
It is funny how big the props look on a Supermarine or a Corsair.

tahustvedt
11-26-2006, 12:32 AM
Another thing. A scale diameter makes the plane more challenging to take off, fly and land. It yaws more the the left on takeoff, rolls easier to the left in flight and yaws to the right after landing if the motor is turned off. :)

Matt Jones
07-22-2009, 09:55 PM
I'm building a 1/6 Spitfire from the Brian Taylor plans and was thinking of using a scale 5 blade prop. Did your work OK and how did you make your spinner?