Guys,
I've been looking for an answer to this problem for a while as well.
I am presently flying a 5 meter Duo Discus planformed electric on 16 cells.
Climbs well, weighs about 10 pounds. I'm getting about 1000 watts out of the
Aveox system. That's all you can safely pull for any period of time before
melting things. I don't think Aveox has any solutions for more wattage over
a long period. You would need at least a 60 second motor run to get to a
decent height.
I have called EMS. He wasn't willing to sell it separately, maybe in early
2001. He wouldn't define the motor he was using.
Astro has some motors that would seem to handle a bit more wattage for a
longer period, based on gearing/belting. I have spent a lot of time with Tom
Hunt trying to come up with a belt solution for this. He advises against
going with a large system/prop due to gyroscopic issues amongst others.
From what I can tell, you should be able to build and fly a large sailplane,
say under 12 pounds, with a span of under 200 inches just fine with
electrics. Going larger will get expensive. Typical Euro scale kits are
already a bit heavy, so
Electrics guys usually figure the wattage needed by multiplying weight times
watts desired. 100 per lb. for aerobatic. 40-50 per pound will let you
stagger into the air, but that would be difficult to ROG with and it would
take a long time to climb. You would really want nothing less than 70 to 90
watts to make it impressive. Figure the big scale jobs weigh 25-35 pounds.
You can gang astro motors on a belt system and with a big enough controller
to get this sort of power. Don't try it with the Aveox. You can't run
multiple Aveox controllers off the same battery pack, and you wouldn't want
to run them seperately as you will invariably have one out of "synch" with
the other. This will lead to a melted motor from overamping it.
I came across a cool servo controller. Allows you to program up to 8
discrete steps each for 4 servos operated off one radio channel. I don't
have the link here, but it would serve well to operate the mechanisms needed
for the up and go type mast off of the throttle stick, much like the Antares
does. I can get it for anyone that needed it. The device is about $65, and
the programmer device is about the same.
Enough of my ranting. I would encourage anyone interested to pursue this,
if you find a reliable method to do so, please let me know!
Lee Estingoy
New Orleans
- Original Message -
From: "John Derstine" [EMAIL PROTECTED]
To: "Adam Till" [EMAIL PROTECTED]; [EMAIL PROTECTED];
[EMAIL PROTECTED]
Sent: Monday, December 11, 2000 1:51 PM
Subject: RE: [RCSE] Antares Sailplane; Darn You SEM
EMS in Germany markets 1/5 to 1/3 size up and go sailplane electric
system.
The engineering is done for such a system. I don't know if he will sell it
separatly from his plane packages or not. See the scale soaring page for
a
link to EMS on the index page, and a hot link to the Antares site.
John Derstine
E-mail; [EMAIL PROTECTED]
Scale Soaring: http://www.Geocities.com/~scalesoar
-Original Message-
From: Adam Till [mailto:[EMAIL PROTECTED]]
Sent: Monday, December 11, 2000 3:46 PM
To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: [RCSE] Antares Sailplane; Darn You SEM
1450"^2 of wing area
215" span
27.2:1 aspect ratio.
21.5" scale prop diameter (max)
Has anyone done anything like this that might be able to give me some
pointers? Or, failing that, could someone disprove the whole concept and
save me thinking about it anymore...
Thanks as always,
Adam Till
_
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