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May 02, 2012, 07:20 AM
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TripleW's Avatar
Did you see this one Scott?
http://www.youtube.com/watch?feature...&v=I_Q5jrV7Ja4

Seriously though the XF-11 would be Awesome! Someone built one recently. I think it was in the scale forum.

Nope it was in the Giant section.
https://www.rcgroups.com/forums/show...ighlight=xf+11
Hughes XF11 (3 min 47 sec)
Last edited by TripleW; May 02, 2012 at 07:26 AM.
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May 02, 2012, 04:08 PM
Bypass Ratio = Infinity
scatsob's Avatar
Thread OP
That’s awesome! Two of these CR50 motors with some 14" 4 blade props would be slick. I swear you can hear the props cutting the grass as he is taxying out.
May 02, 2012, 06:15 PM
http://roys-rc-tv.webs.com/
Basingstoke Roy's Avatar
Going back to the Gannet.
I don't know if you've come across the tread before, from my country man Rick Vale
https://www.rcgroups.com/forums/show...1274083&page=8
May 02, 2012, 06:41 PM
building building building!
aerophilia's Avatar
I knew I'd seen that model before! Thanks for posting that link Roy. He did an amazing job.

That plane weighs 15 pounds, and the motor is specced at 2050 watts. Although I'm sure you could put a lot more through it as it's very close to the CR50 in terms of its size. Thats measly 136 watts/pound. And the owner says it's still overpowered! https://www.rcgroups.com/forums/show...&postcount=132
Last edited by aerophilia; May 02, 2012 at 07:07 PM.
May 02, 2012, 07:46 PM
Bypass Ratio = Infinity
scatsob's Avatar
Thread OP
I have not seen that thread...very cool. A true work of art. One day when I have the time I will build like that, but for now I will be in awe of the people that do. The folding wings are awesome. That motor is exactly the same size as the CR50, 5025. I would love to know how manufacturer’s rate motors. It seems like most can be run well above rated specs without destroying them. I guess they have their reasons.
May 02, 2012, 08:10 PM
building building building!
aerophilia's Avatar
I'd like to know how they rate motors as well! That Himax motor does seem well under-rated. I should spin mine up and do some testing. I comes supplied with 15x10 props and they recommend 6S. It is an incredibly well made motor. It seems like the fairy gannet is using the stock props on 5S. So I have asked what amps/watts/props etc are.

Anyway, back to spitfires! Scatsob and I were talking about cooling motors. Here is a setup that is working extremely well in a seagull MXS-R. Just some plumbing pipe to push the air straight onto the motor. Then I have an exit hole at the back of the fuse that is around 3-4 times the size of the inlet.
https://www.rcgroups.com/forums/show...6&postcount=15

I have also seen people using small 12V computer cooling fans to get some air circulating inside the cowl. Or even adding tabs made from tape to the bell of the motor to create some airflow!
May 02, 2012, 09:16 PM
Bypass Ratio = Infinity
scatsob's Avatar
Thread OP
That is EXACTLY was I plan on doing with the Spitty. I am going to pipe air from the intake scoop under the cowl and blow it directly on the motor. The exhaust will be through the exhaust stacks. Bob P from accross the pond did the same thing with his and he said it worked great. I just wish the plumbing was going to be as easy as your MXS.
May 03, 2012, 04:18 PM
Hooper, full throttle!
Tommy D's Avatar
A wise man once told me if you need a Hurricane to cool your power system your doing something wrong. Just saying......
May 03, 2012, 05:47 PM
Bypass Ratio = Infinity
scatsob's Avatar
Thread OP
Point taken, but I disagree. Most people hang their motors out in the wind where cooling is not a problem. I don’t have that luxury with the spitfire. And we are not talking a hurricane....just a slight breeze.
May 03, 2012, 08:44 PM
Registered User
Full scale planes have all sorts of venues for channeling air to and around the engine compartment. As do cars and motorcycles, snowmobiles and ......
May 04, 2012, 11:43 PM
Hooper, full throttle!
Tommy D's Avatar
And if you need that ram air to keep the motor from going south your doing something wrong. You have selected the wrong cell count or kv or prop size or....
May 05, 2012, 08:35 PM
Bypass Ratio = Infinity
scatsob's Avatar
Thread OP
So you are saying you don't actively cool your motors?
May 06, 2012, 05:04 AM
building building building!
aerophilia's Avatar
Just as a matter of interest, I have been in contact with Xoar props the last few days. They make a series of 3 bladed props that are designed for electric setups. And, they have said they are available as a pusher prop! Lightweight, and range from 10" to 32" diameter

http://www.xoarintl.com/props/model-airplane/PJI-E.html
May 06, 2012, 05:29 AM
Bypass Ratio = Infinity
scatsob's Avatar
Thread OP
Man, the only problem I have with Xoar is their propellers are so dang expensive. $72 for a 16x10 three blade.
May 06, 2012, 05:46 AM
building building building!
aerophilia's Avatar
Ouch! Didn't think they would be that much. Makes buying 4 to test a little bit prohibitive. And I'm willing to bet that being lightweight for electric setups means they are fragile.


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