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Old Sep 08, 2003, 06:06 AM
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JVBAV8's Avatar
Honolulu Intl, Hawaii, United States
Joined Jun 2003
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New GWS F4U retractable 350 power combo?

Hi everyone,
I'm trying to optimize the eps 350c power system that came with my corsair

GWS CEO thanks for a great kit
it went together well in only 2 evenings
my only modifications were using dubro easy connectors (should include some maybe unless it raises the price too high) and put on the new GWS heavy duty retracts
(I ordered them from Hobby Horse and they said MPI on the package. Although they did fit well in the supplied plastic GWS mounts and seem to be very strong)
A very good kit design with nice rivet detailing on the top side, excellent value for only $60 including motor and 10x6 and 9x7 props.

Anyway I'm trying out 2s1p etec 1200s with 10x6, 9x7
also tried 3blade 9x7 and 4blade 10x8

3s1p etec 1200s with 8x6 and looking for 4blade 8x8

My friend blew 2 eps 300s using 3s1p etec 1200s with 10x6
this morning he flew his zero on 3s1p with 8x6
p calc says >9a but his motor burned my finger after he landed

My motor gets hot with 3s1p 8x6
stays cooler with 2s1p and 3blade 9x7

Anyone know these combos well?
my goal is to max performance while sacrificing durability as little as possible (as if everyone isn't striving for this)

Anyway it was fun playing battle of the Pacific with a Corsair and a Zero!
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Old Sep 08, 2003, 06:07 AM
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wheels up
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Old Sep 08, 2003, 06:08 AM
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looks clean in flight even though they are external
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Old Sep 08, 2003, 06:18 AM
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Honolulu Intl, Hawaii, United States
Joined Jun 2003
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weight 15.2 oz
4 gws pico servos
fma 5 channel micro receiver
fma 20a esc
2s1p etec 1200s

will fly nice at higher power settings 2s1p
power off glide is also nice
instruction manual text says 60mm for cg
picture says 50-55 mm
also says +-3mm for tolerance

60mm - tail heavy, pitches up on deceleration, need to push down to get on step
55mm - seems good and neutral
still might move forward slightly
I like it to descend rather than slow down with thrust reduction

GWSCEO might want to update manual
I can see the improvements of the manual and kit design compared to the Zero
again thanks for giving us pleasure by improving your kits
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Old Sep 08, 2003, 06:40 AM
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United States, CO, Boulder
Joined Jul 2003
411 Posts
Thanks for the good info

Hi JVBAV8,

Good info on the CG characteristics. I should be receiving my Corsair today from e-flightline with their recommended upgrade package (Here's a movie of the corsair using Mega 16/7/7 GWS 400c "B" 3s2p Etec 1200 APC 10x7E). Like you I prefer decent to stall so I'll go with the 55mm CG you described. Thanks!

As for the ideas on the Lipos to use, I'll defer the question to the experts here at E-Zone.

Cheers,
Dave
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Old Sep 08, 2003, 07:23 AM
T-A-F-K-A crash_out
United States, TN, Jackson
Joined Jan 2003
559 Posts
I haven't used Li-Po's on my Corsair yet, but I did do some amp tests with my 5/4aa packs. I think 9 amps is the practical limit on these EPS 350's. If you'll notice on GWS' website, they say not to use voltage that causes more than 9 amp draw. That being said, I think the 3s pack supplies around 11.5 volts, and would puch the draw well past the 10 amp mark on the 10x6 prop. That's not to say it won't survive, but I wouldn't do it often if I wanted the motor to survive. That's also well out of the safe range for a 3s1p pack of etecs. A 2s pack would push it to around 6 amps, at which these motors and batts should last for a long time.

Something I noticed is that the EPS-350 seem to be timed the same as a stock EPS-300 (at least the backplate is in the same spot).
So I wonder if it could put more power out after being re-timmed. Maybe I'll try this when I get an extra motor for backup.

It's not lithium batts, but here's the post I did the tests on.

http://www.rcgroups.com/forums/showt...hreadid=146553

I've got to get anoher pack of Etecs, or maybe some of the new Kokam 1500HD's, a tach, then I'm going to do an in depth test on the EPS-350 that came with the kit. All static tests, but it's better than nothing.

Nick
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Old Sep 08, 2003, 07:32 AM
agriebel's Avatar
Madison WI
Joined Aug 2003
1,805 Posts
Ya, 11.4volts is too many for the 350 motors...short lifespan as you now know. Show a picture of how you set up the servo inside the wing for the retracts. I would like to see how you did it.
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Old Sep 08, 2003, 09:36 AM
MultipleCrashSurvivor
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USA, HI, Honolulu
Joined Jan 2003
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JVBAV8
Where do you fly? I'll maiden my P-51 this morning at Kapiolani Park before work. I have a 010 in it with stock gearing but powered by TP 2100 3S.

I'd love to see your Corsair fly, especially with the 350.
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Old Sep 08, 2003, 01:40 PM
Motor Maniac
Orange County, CA
Joined Feb 2002
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Watch out when using 3S LiPo and 4 servos. Your BEC might not like it, especially if there is some binding on the retracts or another servo. If you do want to go with this setup you may want to remove the rudder servo so you are using only 3 servos.
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Old Sep 08, 2003, 09:52 PM
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Honolulu Intl, Hawaii, United States
Joined Jun 2003
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thanks for the replies
that fma 20 esc can do 4 servos I think - no problems yet
yes I am trying to run 2s1p etec 1200s if possible

agriebel - here's the pics
1) cut out a bay for the gear servo in front of the aileron servo bay

2) use a sharpened aluminum tube to hand drill out a tunnel for the gear pushrods - go straight from the stock gear bay (before gluing in the plastic inserts) to the center of the wing in front of the aileron servo bay (track straight down the center of the airfoil)

3) use sleeved pushrods or golden cable with easy connectors and servo wheel

4) mount gear servo
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Old Sep 08, 2003, 09:53 PM
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hot melt glue servo mounting
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Old Sep 08, 2003, 09:54 PM
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from the top
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Old Sep 08, 2003, 09:55 PM
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gear mounting
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Old Sep 08, 2003, 09:56 PM
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pushrod
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Old Sep 08, 2003, 09:57 PM
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dubro keeper
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