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View Full Version : Great Plane Combat Corsair to Racer 57 EP


BTU44
05-27-2006, 01:08 AM
Hello,

This is my first post on WattFlyer due mostly that my written skill are not very good.
I apologize if you guys find this sometimes hard to understand. But I think this plane will be of interest so Iíll try my best.


I have taken pictures as the build went on so Iíll explain a little about each one.


Here I have removed all the covering. It came of pretty easy with little blue glue to sand off.

The top deck of the fuselage has been cut away. I built ply former to go across the bulkheads that were cut off.
The canopy is from the Great Plane Combat Mustang


The top mount aileron servo cut outs are shown here too.
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BTU44
05-27-2006, 01:24 AM
Here I have the top of the fuselage finished.
The cut outs in the horizontal elevator removed about a .4 of a once. The new, larger rudder still weighs a little less than the stock rudder. I used CF tape to add some stiffness.

This motor and battery mount are a SKYKING from RCG design. I made it from .o4Ē 5051 aluminum sheet.
The motor is a AXI 2820/10. The batteries will be Thunder Power 1320 3S. They be wired in parrellel for close to 4000mA total.
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BTU44
05-27-2006, 01:41 AM
Now Iím ready for covering. I have never done it before and not expecting it to be much fun.
This picture shows the covered over exhaust depression. That way I can film cover over it instead having to paint it.
The aileron servos covers are made from aluminum sheet. The Hitech HS65HB servos with the Hobby Lobby mini servo side mounts worked out well.
The tube in the left wing was going to be an air speed pitot tube for a data recorder. Unfortunately in the end, the data recorder would not fit and could not afford the weight. To bad, that would have been pretty cool.
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BTU44
05-27-2006, 01:55 AM
I read that Combat Corsair may have there elevators break in-flight during high speed pull outs.
I used more CF tape so it hopefully doesnít happen to mine.

The other picture shows the comparison of the 1 inch taller rudder to the stock one. The F2G Super Corsair had a 1 foot taller rudder.

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BTU44
05-27-2006, 02:07 AM
Here are some finished pictures. It came out pretty good. A close up look will show some finish blems but from a few feet it looks great. I got it ready just in time for the Chino Ca. Air Show.

The 57 and SOHIO graphics were done by Kirby Kustom graphics. He rushed them to me so I could make the airshow. Thank again.
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Three-Wire
06-06-2006, 04:08 AM
Great job on the conversion! Race 57 looks fantastic!! You did a beautiful job with the mods and the covering, too. How's she fly?

BTU44
06-06-2006, 08:33 PM
Three-Wire,
Thanks for kind words.
I finished revising the wire routing so Saturday she’ll fly. Hope to get some in-flight photos.

BTU44
06-07-2006, 08:59 PM
I have finally got the wiring routed in a pretty usable configuration. Before I had the battery wires going into the fuselage and it was a bit of a pain to get everything connected.

This shows the male Deans connectors that were glued into the firewall.

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This is with the batteries installed. It is now much easier to install and remove the batteries. I no longer need to remove the wing.

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This picture shows the placement of the electronics. The FMA Encore receiver is so light that I placed it in the back part of the fuselage. Plenty far from other electrical noise sources.

The extra piece of balsa going across the fuselage is for strengthening. This plane is going to be underhand launched. Before, gripping the plane hard enough for launching, the fuselage would flex and make cracking noises. Not good!

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This is my method of adding a measure of safety to in-plane battery charging.
The black panel on the field box is an Aerocool Gatewatch. Its intended use is for monitoring fan speeds and temperatures of various parts in a PC computer. It is the temperature monitoring that I'm using.
The temperature probes supplied with the Gatewatch are placed on each of the battery holders. The cable going to the plane has the charger connection and the temperature probe connections. The Gatewatch panel has an audible alarm that is set to go off when a temperature of 104 degrees is exceeded by any of the probes. I am thinking this will give me enough time to disconnect the charger and remove the batteries.
What I don't know about is can LiPo batteries go into a runaway condition. Meaning after disconnecting the charge current will they continue to get hotter.
I invite comments?

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BTU44
06-14-2006, 02:01 AM
I did some static testing and thought I would pass on the results.

These are with these specs. for the plane. I used a Watts-Up meter and a Lyman trigger pull gauge for measurements.

Motor: AXI 2820/10
ESC: Jeti 40 Plus
Battery: 3) T.P. 1320mA LiPo wired in parallel
Prop: APC 10 x 7 E

AUW: 3 lb 2.4 oz

Fresh charge Amps (Watts): 46.46A (522.5W)
After 5 minutes of cruise power: 41.6A (430W)
@ 10 minutes ( end of effective charge) 40.3A (390W)

Static trust (fresh charge): 3 lb 2.9 oz
@ 5 minutes: 2 lb 14.8 oz
@ 10 minutes: 2 lb 12.4 oz

A few pictures:


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BTU44
06-14-2006, 02:29 AM
Well she flew this Saturday. What an awesome flyer she is. Very smooth and controlled in the air. I would say as easy to fly as my Super Star EP.
Hand launching is simply a gently underhand toss. No problem with torque rolling as airspeed builds. Stays nice and level.
Took her up to maximum altitude (at my field itís 400 feet) and did some stall testing. Iím happy to say stalls are not a problem. At level flight, full up elevator, and motor off she just gets mushy and then drops her nose. Only way to get a mild tip stall is to be climbing, using full up elevator with the motor off. Then it is short lived and easily recovered. I was worried since sheís over specíd max weight she would be a handful.
A plus of the paint scheme is that sheís very easy to see in the air. It was overcast that day but I had no problem maintaining situational awareness of her in the air. I got many compliments of her beauty in the air.

Here are some of the best pics.

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buzzbomber
06-20-2006, 07:08 PM
Very nice job on the Corsair! And as for your written English, it far surpasses that of many others.

Doppelganger
06-21-2006, 02:48 AM
BTU44, I want to be like you when I grow up!:D The skill of some of the members here is just astounding. I can barely build an ARF!:eek: Thanks for sharing.:)

Steve

BTU44
06-22-2006, 12:06 AM
Iím glad people are finding this worthwhile. This is only my third plane and before this most challenging modification I did were dual aileron servos on a Hobbico Super Star. This project was to push my ĎState of the artí and learn as much as I can. These forums were instrumental to this plane success. I learned almost everything from all you guys.
It does me proud to be able to finally contribute to a forum thatís helped me so much.

Barry

dimadee
06-22-2006, 06:30 AM
BTU44,

Your Corsair looks sensational! You must be very proud of your achievement. I am glad to hear that it flies as good as it looks.

I am nearly finished my Ace Simple Series Corsair (converted to e-power using a 400XT, 8x6 or 9x6 prop and Electric Power 3S 2200mAh LiPo's ). I have not seen the red colour scheme before - if I had, my Corsair would be red and white also! :mad:

I will post some pics when I am finished. My biggest challenge is access to the batteries, as I do not want to cut a hatch in the fuselage. I have been thinking of a quick release wing mechanism, but your idea has got me thinking again. How do you hold on your engine cowling?

Old Fart
06-22-2006, 04:49 PM
dimadee,

I'm not using this method on bird #2 (had heating issues with bird #1), but when I was running the Fiegao/gearbox the 4s was in the cowl. I just made it "twistlock"

Bird#2 has a Power 25 outrunner, batteries in the fuselage. Unfortunately, also has 2-1/2 oz of lead in the nose :(

BTU44
06-22-2006, 07:01 PM
dimadee,

Originally I was using strong magnets on the fire wall and washers on the cowling ring. With to much wishful thinking I was hoping this would hold.
It didn’t, during static testing I guess the cowl pressurized and broke the magnetic hold. The cowl moved forward and rubbed against the propeller.
Now I have four external screws holding the cowl in place.
I think ‘Old Fart’s (said respectfully) method is much better. I would be using it if I felt I could keep the white stripe aligned after the change.

Old Fart
06-22-2006, 08:05 PM
BTU44, don't worry about the "respect" - I've been the Old Fart on so many forums (Jeep, R/C) that I'm used to it.

I liked that mounting for the cowl, almost went back that route - but would have to have bought 3 more 1320's to go your route (although I like that mount!) I'll see how my parallel 2100/15c/3s Apex's work.

BTW, if anyone has this kit and hasn't built it yet - trace the plywood ring for the cowl on paper and file it, as Great Planes does NOT include one in the replacement fuselage package! When I nosed in Corsair #1, I had to argue them out of it, as well as the tailcone.

Fuselage kit _does_ include the belly pan - which should have been part of the wing part number.....

Eplane65
09-01-2006, 04:17 PM
BTU44,
No doubt the AXI 2820/10 is the right motor for this. That's what I use except I'm using a 3S1P Kokam 3200 battery. I get two 8 minute flights with it without stretching my luck. This plane's a blast to fly!

BTU44
09-05-2006, 11:11 PM
Eplane65,
I’m also very happy with this motor. A good cruising speed is less than ½ throttle. The plane has virtually unlimited vertical, meaning the plane is slowing while vertical but I hit the 400 ft ceiling before it falls out of the climb.
I noticed in another post you were using a 10x7 propeller at a similar amp draw as my set up. When I tried the suggested 11x8 prop, my current draw was over 50 amps. MotoCalc 8 calculates that the 11x8 will draw 39 amps. This experience tells me that a watt meter is mandatory for electric plane setup.

For anyone interested, I have about 50 flights on this Corsair and these are the highs and lows.

Highs–
Very smooth easy plane to fly. No bad habits.
Above wing aileron servos working out well. Plane lands and slides along grass nicely.
Rudder modification I think was worth the weight and effort. The plane does snap rolls and stall turns really good.
I have not crashed it yet.

Lows-
My plane is 2 oz over max weight. ‘With out a helper’ launches can be hair raising. I have made the gophers duck a few times.
Landings are a little fast. If too slow, the plane drops flat and fortunately doesn’t drop a wing.
Biggest maintenance problem is peeling trim tape. Constantly reattaching with thin CA and a tooth pick.
My original vertical stabilizer design was bad. Having the grain of the balsa going along the base was very weak. The CF tape I applied was only thing holding the rudder on after one particular flight. Fixed now with solid balsa sheet with the grain going up.

Barry

Eplane65
09-06-2006, 05:22 PM
BTU44,

My Corsair weighs 2 lb, 14 oz. ready to fly.