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Old Nov 28, 2009, 07:02 PM
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Help!
GWS replacements

I've been building 28 to 40 inch WS foamies for the past few years and have pretty well depended upon GWS 300 and 350 power systems. Yes, I have given brushless motors a try but just don't care for them, probably because they require 3s lipos to outperform 2s brushed systems and I've always got a good collection of 2s lipos on hand.

(That, and I've found the brushless systems to be a bit less reliable, subject to fluttering etc.)

My question to the power system gurus is basically - "Now that GWS systems seem to be so hard to find and it is rumored that GWS will soon go under, what is a comparable system to the GWS 350C system which comes in a 5 or 6 to one gear ratio, at a similar price?"

I don't post much, so I'll lurk about waiting for an answer, if indeed there is one.

Cheers,

Don
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Old Nov 29, 2009, 04:40 AM
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East Anglia, UK
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Quote:
Originally Posted by Don Patrol View Post
I've been building 28 to 40 inch WS foamies for the past few years and have pretty well depended upon GWS 300 and 350 power systems. Yes, I have given brushless motors a try but just don't care for them, probably because they require 3s lipos to outperform 2s brushed systems and I've always got a good collection of 2s lipos on hand.
Then you are picking the wrong brushless system.


Quote:
(That, and I've found the brushless systems to be a bit less reliable, subject to fluttering etc.)
They all do that on start up. Better ESCs do it less.

Quote:
My question to the power system gurus is basically - "Now that GWS systems seem to be so hard to find and it is rumored that GWS will soon go under,
No one has saiud that to me, anywahere.. Source of rumours?
Quote:
what is a comparable system to the GWS 350C system which comes in a 5 or 6 to one gear ratio, at a similar price?"

I don't post much, so I'll lurk about waiting for an answer, if indeed there is one.

Cheers,

Don
Very hard to find brushed motors at all these days.

The best brushless alternative is a very low KV motor like the esskay 900XT? Is that the one?

Run on 2s LIPO that will swing a 9" prop nicely.

There are a few car style motors in the 280/300 size that are better made and still brushed.

Kyosho do one.

And there are all metal gearboxes out there as well.
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Old Nov 29, 2009, 09:04 AM
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Columbus,Ohio
Joined Nov 2005
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Don- I don't agree with your statements about brushless or GWS.

However, if you really want to stay with the brushed geared setups, nothing wrong with that.
My advice is to place a wanted ad in the power section (wanted/for sale).
I have to believe that there are alot of motors sitting in drawers out there.
Matter of fact, I have maybe 25-30 brushed setups in one. All from never used to -where in the world did this thing come from.

Also I know of several online vendors that stay in stock on the brushed stuff.
BP Hobbies being the first I think of-
http://www.bphobbies.com/view.asp?id=V197541
http://www.bphobbies.com/view.asp?id=V300489
http://www.bphobbies.com/view.asp?id=A1190099

Good luck.
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Old Nov 29, 2009, 09:30 AM
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If you need to spin something like an 11x7 GWS HD on 2s, an Axi 2212/26 (~920Kv) is ideal:
20oz thrust @ 35mph from 10.8A/80W. Far lighter and better than a GWS can motor.
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Old Nov 29, 2009, 01:51 PM
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Raleigh, NC
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If you like the flexibility of gearboxes, you can always consider using an inrunner brushless motor in a gearbox. Cobri gearboxes are a good option. Geared inrunner brushless motors will give you the best options for pretty much any prop size you want to run...

http://www.e-flightline.com/gearboxes.htm (see chart for all possible gear ratios)

I'm running an Eflite Park 400 4200 kv inrunner in a 350C GWS gearbox using a 2.8 to 1 ratio with a 7x6 APC SF prop. right now it's on my 42" flying wing. Very efficient setup. On a 1750 3S lipo I get 10 to 12 minutes of flight. And that's with the ability to get up to 70 mph and 28 oz of thrust. (Granted I'm not running full throttle all the time)
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Old Nov 29, 2009, 03:23 PM
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Quote:
Originally Posted by cjbucher View Post

I'm running an Eflite Park 400 4200 kv inrunner in a 350C GWS gearbox using a 2.8 to 1 ratio with a 7x6 APC SF prop. right now it's on my 42" flying wing. Very efficient setup. On a 1750 3S lipo I get 10 to 12 minutes of flight. And that's with the ability to get up to 70 mph and 28 oz of thrust. (Granted I'm not running full throttle all the time)
And then you can turn right around and run that same motor on a deep gearbox and swing 12"-13" props to generate enough thrust to pull stumps with. That's the beauty of those gearboxes...

Chuck
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Old Nov 29, 2009, 06:39 PM
c/f
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Go to www.gwsprops.com if you want gws anything. He still receives and ships out by the hundreds the 5X3 and 5x4 props so popular on the Eflite Sukoi as an upgrade with the rubber spinner.

The recent supply shortage is rumored to be the cost and profitability of shipping a full container across the pond when many asian wholesalers have picked up GWS offerings.

Not to mention the HUGE taxes California has imposed and collects years later for imported goods into the state, Cali working with customs has tracked down some jet jocks, sending them a bill for cali import duty fees in excess of $1000 on a $2500 jet, only to receive the bill 12+ months later.

Guessing USA/Cali is low on the feeding chain right now................
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Old Nov 29, 2009, 07:40 PM
Motors beat engines!
Milwaukee Wisconsin, United States
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Quote:
Originally Posted by Dr Kiwi View Post
If you need to spin something like an 11x7 GWS HD on 2s, an Axi 2212/26 (~920Kv) is ideal:
20oz thrust @ 35mph from 10.8A/80W. Far lighter and better than a GWS can motor.

Lighter, but better?

GWS 400h ( 5.28:1), retimed with 3s turns a 11x7hd at 5190 rpm at only 6.7 amps and 73 watts for about 20 oz thrust. Thats 7.67 g/w, pretty good in my book. The axi above is getting 7.08 g/w.

Dean in Milwaukee
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Old Nov 29, 2009, 07:47 PM
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Quote:
Originally Posted by DeaninMilwaukee View Post
Lighter, but better?

GWS 400h ( 5.28:1), retimed with 3s turns a 11x7hd at 5190 rpm at only 6.7 amps and 73 watts for about 20 oz thrust. Thats 7.67 g/w, pretty good in my book. The axi above is getting 7.08 g/w.

Dean in Milwaukee
But the Axi motor is lighter than the GWS motor+gearbox. A LOT lighter. Plus, you don't have to retime it or replace any bushes.
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Old Nov 29, 2009, 07:56 PM
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How does grams of thrust per watt indicate efficiency of power combos?
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Old Nov 29, 2009, 08:01 PM
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Try

www.bphobbies.com
www.allerc.com

Rich
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Old Nov 29, 2009, 08:06 PM
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Quote:
Originally Posted by NoFlyZone View Post
How does grams of thrust per watt indicate efficiency of power combos?
It doesn't, it only takes thrust into account, not velocity and thrust as it should.
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Old Nov 30, 2009, 07:38 AM
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United States, OR, Lake Oswego
Joined Dec 2003
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20-30-3500kV Brushless In-Runner Electric Motor.

Using this in a 14-16oz foamy GP yak 55 3d 3s1300
Will hover&climb vertically, using 1000mah for 15min flight,
4amp average if my math is correct. GB 6.4:1 prop APC 11x3.8 SF


$8.99
SPECS: Motor Diameter: .787" (20mm)
Motor Length: 1.18" (30mm)
Shaft Diameter: .079" (2mm)
Shaft Length: .413" (10.5mm)
kV Rating: 3500 rpm/V
Weight: 1.6oz (45g)
Input Voltage: 7.4-11.1V
Max. Constant Current: 8.5A
Max. Surge Current: 15A
Max. Constant Watts: 94W
No Load Current: .6A
http://www3.towerhobbies.com/cgi-bin...?&I=LXLWW5&P=7
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Old Nov 30, 2009, 08:28 AM
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Chattanooga, Tennessee, United States
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Quote:
Originally Posted by nyflyer1 View Post
It doesn't, it only takes thrust into account, not velocity and thrust as it should.
I agree absolutely... thrust without pitch speed is a useless parameter.... but g/W is still a useful measure when comparing two motors which are generating the same pitch speed (at least enough to fly your particular plane)... the one with the highest g/W output will be the more "efficient" motor.
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Old Nov 30, 2009, 01:50 PM
soar-ne
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Don:

I was/am in the same position as you. When I retired I stocked up on GWS 350/ 300 units as I fly the same size planes as you for the most part. Now as I see the supply at the LHS drying up I have been watching the For Sale colums on the "big three" forums and have been buying HiMax 2015 and EFlite 370 brushless inrunner motors or any 20mm short can for that matter and 12-18 amp ESC's for very reasonable prices. Get the lower KV models, not the 5K plus EDF ones and they will almost mirror the 350's. They seem to go cheaper than outrunners as nobody seems to like gears nowdays.Get a gear puller and use the brushed pinion gears in the 300/350 boxes and they will last a good long time.........

Happy Flying
Bob
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