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Old Sep 26, 2003, 01:04 PM
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Irvine, Calif USA
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Mini-Review
Rafale by Aeronaut





Is anybody besides Ulf Herder and Joerg in Germany and K Saunders in the UK flying the Aero-naut Rafale?

I am looking at a setup with twin B50-18S (or L) or 22/30/2 with two Beats and 14 GP 3300 NiMHd cells each for each fan (I can buy nine packs for one equivalent LiPo HD pack ).

I am planning on having the Hackers modified by our machine shop to allow for large front and back cooling holes.
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Old Sep 26, 2003, 01:06 PM
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Old Sep 26, 2003, 01:38 PM
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Hey Herb what about C motors with XL rotor's, think it's worth it?


Barry
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Old Sep 26, 2003, 02:18 PM
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IMHO as long as you stay with a 1 kilowatt or so limit per motor there would be no reason to go for the bigger / heavier / more expensive motors on this twin. 2,000 watts should be enough even for Herb
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Old Sep 26, 2003, 02:28 PM
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I was thinking about 650 Watts per motor. That's about 1300 Watts total. For each motor about 14 V x 46 A = ca. 650 Watts peak.

5 minute flights should be plenty, as I said I don't know anybody that would want to fly the Rafale for more than 5 minutes or so anyhow .
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Old Sep 26, 2003, 02:42 PM
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a new Costa Mesa coastal defense fighter!
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Old Sep 26, 2003, 03:13 PM
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Quote:
Originally posted by Herb
I was thinking about 650 Watts per motor. That's about 1300 Watts total. For each motor about 14 V x 46 A = ca. 650 Watts peak.

5 minute flights should be plenty, as I said I don't know anybody that would want to fly the Rafale for more than 5 minutes or so anyhow .
Hi Herb,

I can tell you that you will find your own mental limit flying a fast jet for 8 to 10 minutes, depending on your mental conditions.

On saturday at Aspach I was able to do a 10 minutes show flight as I was in good mental conditions.
On sunday afternoon I was mental not so strong, so I decided to land after 8 minutes! The landing was not so perfect as the landing on saturday as I had problems with concentration.

5 to 6 minutes flying with a lot of power is plenty enough.

Regards,

Ulf
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Old Sep 26, 2003, 03:41 PM
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Thanks Ulf I have looked at your weight and power figures, and I'm planning on a similar setup for mine. Would the HW-620's be of any benefit? I suppose you can get the same efflux on a 90mm fan by just constricting the outlet.
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Old Sep 26, 2003, 04:59 PM
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nashua nh 03060
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rafale

Herb,
I have in partially assembled in my basement if you want retracts 620s are the only way to go.

Derrek
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Old Sep 26, 2003, 05:38 PM
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Thanks for the info, I was looking at the 600's as well:

http://www.retracts.com/600.htm

The first flight most likely will be bungee launched, with retracts out only for landing. And one GP 3300 pack only (instead of two).

I was considering twin JePe Spiderfans (220 grams each including carbon motors !! ) but most likely would have to wait a looooong time for those. They would shave off a hefty 8 oz (!) over the 30/2 setup, and 4 oz over the 20/3 setup.
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Old Sep 26, 2003, 06:35 PM
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Ref the ducts & retracts, Kevin S scratch-built his ducts to fit, and also arranged his gear's legs to twist and retract. I've already posted pics on this forum somewhere, but should be able to rustle them up again from archives if you'd like a re-print

Ref the GP3300s, I'm with you. I don't know how long they'll last at 48A max and farless on average, but my 2x20-cell packs certainly work well, better output than 22 CP1700 to such an extent that the planes don't notice the extra weight.

Gonna get more GPs.

Gordon

Gordon
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Old Sep 26, 2003, 09:33 PM
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Herb, I'm not flying one but have one here awaiting assembly.
I have the all composit version. Glass wings and ailerons.
I'm not sure on motors yet but the Kontronik Fun 600-18 on 16 cells each is looking best to me at the moment. That will be 750 watts per side, mabey a little higher useing the GP3300's.

Speaking of waiting a looooong time for fans, .... I have two Schubeler DS-51-FAN- 3ph ready to spin into service.

As for the retracts I was originaly leaning to the EJF but the Spring Air's might be worth the extra weight for the no air/air leak fail safe of gear down peice of mind. What do you think ?
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Old Sep 27, 2003, 01:37 PM
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I am considering various power options. And the all-important crucial weight issue...

The Rafale with the springair retracts was apparently so overweight that it could not takeoff. Each fan/motor setup was reported to weigh 450 grams - ouch . I don't know if that situation has changed in the meantime.

http://www.rc-network.de/cgi-bin/ubb...c;f=5;t=000020

For my setup I have excluded the Fun-600 because of weight. I've considered the Fun-500 but almost certainly will go with the 20/3's saving another 2.4 oz.

For the price of two DS fans I can buy a second Rafale including twin WeMo fans so I will stick to either the JePe or WeMotec fans.

For the price of a LiPo pack I can buy two more Rafales with fans, so for now I will stick with a few $110 28-cell GP packs .
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Old Sep 27, 2003, 01:39 PM
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Ulf likes a long ramp for his:
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Old Sep 27, 2003, 01:50 PM
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Another option that's being considered by some Germans is a single fan (say 120 mm size) instead of a twin setup. You'd have to make your own ducts, but in the end the weight saving will be significant (very roughly about 10 oz),

http://www.rc-network.de/cgi-bin/ubb...5;t=000020;p=4

The cost and complexity is also reduced somewhat, all you need is a single Hacker XXL lawnmower motor & controller.

I am quite convinced by the German's claim that this setup will work well, having seen Robert's Rafale fly well with both twin MF and single Midi.

But the sound is imo totally different. A single fan just does not sound the same as two high pitched twins ....
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