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Old Apr 02, 2002, 07:15 PM
Motors beat engines!
Milwaukee Wisconsin, United States
Joined Feb 2001
4,564 Posts
How fast could a GWS powered plane go?

After watching my s1 / 8x6 / qualcom powered Drenalyn whizz around at what must have been at least 20 mph, I got to wondering just how fast a IPS pwered plane could be made to fly.


Picture a s2 / 7x6 / qualcom inserted into something like a stinger at around 75 in/sq. Wingloading would obviously be much better than a s400 powertrain, but what kind of speed is possible here?

I'm guessing you could prob fly at around the powertrains pitch speed, but I have no idea what that is. 30 mph? 40?


The idea of lowbuck park pylon flying is appealing, and I'm guessing sport flying would be very interesting with this much momentum to work with, much like s400 pylons.


Thoughts or experience anybody?
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Old Apr 02, 2002, 07:27 PM
Heli Bouncer
Looooeeee!'s Avatar
At the Discount Clambake
Joined Feb 2001
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Hi Dean

I was testing my BUD with a S-1 using my old pitch twisted 8x6, which is close to an 8x8 or better. Really scooted on eight 120 mah cells but every thing got way too hot, too fast.. The motor pulls a good 2 amps static on six AAA's using the stock 8x6. I can't help but think that with a light airframe and pack it should really go. Maybe 5~6 oz. and very clean airframe... Micro warmliners
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Old Apr 02, 2002, 10:42 PM
Motors beat engines!
Milwaukee Wisconsin, United States
Joined Feb 2001
4,564 Posts
That you were at 2 amps on 6 cells is interesting. The gws site says it should be about 2 amps on 7 cells, 7.2V.

I did some motocalc figuring, and comparing the s1/8x6 to s2/7x6 on 7.2V, it looks like the s2 has almost 50% more pitch speed. 30 mph compared to 22mph.

Motocalc is of course not the most accurate at these small motor sizes, so what is needed is tach testing. check rpms and see what you really get.

I keep picturing a tiny little fan fold pylon racer.


Think about this too: At a real 30 mph, running for 1/2 hour on the qualcoms, the plane would travel an actual 15 miles!


Are there any other electrics that could go that far on a charge?


Dean in Milwaukee
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Old Apr 02, 2002, 10:51 PM
Master Crasher
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Sunrise, FL
Joined Nov 2001
162 Posts
I have a GWS pico stik F that everyone says does 40mph. Johnson 250, symetrical wing.
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Old Apr 02, 2002, 11:08 PM
Heli Bouncer
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At the Discount Clambake
Joined Feb 2001
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Dean

I can't quantify that reading from my cheap Cen-TEch Digi multi meter, other than it reads charge rates fairly accurately. Doesn't Mr. Lin's site list the 7.2 as the pack voltage for 6 cells? I could be imagining things.

You got me thinking about a G4046 powered warmliner with 3.4 gears I've made up, also using a GWS 6x3 prop, (darn I still wish they made square props)

Hi Sanjoh,.. Man, G4046 screamers, blue fanfold or balsa and film.
Deans got me going on an endurance record plane with Li-ion cells. Are the Electronic Goldmine G4580 Qualcomm's worth messing with? They're 1100 mah Panasonics.


Looee
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Old Apr 02, 2002, 11:47 PM
Motors beat engines!
Milwaukee Wisconsin, United States
Joined Feb 2001
4,564 Posts
The gws site lists both 6 and 7.2 volts for each drive. My understanding is that this would be 6 and 7 cells.

It is interesting that ALL the gws recommended combos don't exceed 2.01 amps.

I ran the s1/8x6 the other day for 25 wide open minutes and the motor barely felt warm when I landed, although I am using a heatsink and it was cold out.

I also tried out a 9x7 the other day with a partially charged battery, still got 15 minutes, and again the motor was barely warm. The 9x7 was an excellent performer on a Drenalyn BTW!
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Old Apr 03, 2002, 07:48 AM
Registered User
Vermont
Joined Mar 2002
2,706 Posts
5 cell should be 6v.
6 cell should be 7.2v.
7 cells should be 8.4v.

People do run 8.4 and greater with GWS motors but I have seen it written that the life span might be reduced quite a bit. I have an 8.4 Radio Shack 9V nimh and it doesn't seem any different than my 350mah nicd 6 packs. Maybe it is an amp thing.

I still can't believe how long I can fly using a just a 9V pattery for power!
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Old Apr 03, 2002, 09:27 AM
Master Crasher
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Sunrise, FL
Joined Nov 2001
162 Posts
Looooeeee!

A 6x3 wth that gearing should scoot using the J250!

I haven't had any luck goin fast with the stock GWS wings. Made a symetrical wing out of 1.5mm foam. Formed it around a quickee wing and put the heat to it. No spar, 6 ribs, doesn't flex at all!

Next revision will be formed over a quater midget wing to get reduce the airfoil height.
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Old Apr 03, 2002, 10:17 AM
Registered User
Wayne, NJ
Joined Apr 2001
473 Posts
My Acro Bipe on 8 cells tachs 24,000 with a 3x2. That's about 50 mph (That's why I fly it on six now, 15 inch span + 50mph = invisible fast).

Mike
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