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Gullwing
11-06-2005, 10:38 PM
I have been hanging on to a GP Combat Corsair for a few months. I built it in mind of converting it to electric. It is 1/12th scale, with the weight range of 2.5 to 3.0 lbs. I put alot of thought and research into the power system. I finally bit the bullet and went with the Hobby Lobby's setup with the exception of the battery. I have a TP 3s2p 4200mah. the setup is as follows
AXI 2808/20
Jeti 30 esc
Thunder Power 4200mah bat.
ACP 10x7E
This setup gives 265 watts and 45oz of static thrust........Ok the problem part... After I installed the power system, I can not get the CG right... I have moved the battery as far forward as possible, moved all electronic forward and figure it will take another 5oz. in the front to balance. It should balance at 2.5 inches from the leading edge. At that weight I will be pushing the 3lbs mark, which will push me out of the 100 watts per pound mark that I am wanting to keep. Does anyone have any idea what I could do? Thanks for any help.........GW

timocharis
11-07-2005, 04:29 AM
I'm so sorry to see that happen again. So many models out there are designed for equipment two or three generations back, and end up tail heavy. Probably this is the case yet again, though I am not familiar with that particular model.

The closest thing I have to good news is, 5oz on the nose will typically mean only about an ounce in the tail. And other than just loading it down with dead weight, or getting a yet bigger motor and battery, your only remaining option is surgery on the tail section. The question is, do you have any weight back there you can get rid of?

Dave

Gullwing
11-07-2005, 04:40 AM
Not that I'm aware of. The model is pretty sparce. In fact most people won't even use this plane for what it is intended for(COMBAT). Funny thing is that if I left it a gasser it still would be tail heavy. The tank sets over the CG and the glow motor only out ways the electric by 2.7 oz. Thing is this model has only been on the market for about one and half years if that. I built it to spec. I see alot of people converting this model and the P-51 version. I will look at the tail section tomorrow and see if I can pull some weight out of it. I think you for your help and your time. I had no idea that an ounce in the tail could make that much difference. DUH the farther away from the CG the less weight that has to be changed. Thanks again Dave..................I will let you know how it goes..................GW Here is a pic or two...........

Crash Test Dummy
11-09-2005, 06:07 PM
I have been hanging on to a GP Combat Corsair for a few months. I built it in mind of converting it to electric. It is 1/12th scale, with the weight range of 2.5 to 3.0 lbs. I put alot of thought and research into the power system. I finally bit the bullet and went with the Hobby Lobby's setup with the exception of the battery. I have a TP 3s2p 4200mah. the setup is as follows
AXI 2808/20
Jeti 30 esc
Thunder Power 4200mah bat.
ACP 10x7E
This setup gives 265 watts and 45oz of static thrust........Ok the problem part... After I installed the power system, I can not get the CG right... I have moved the battery as far forward as possible, moved all electronic forward and figure it will take another 5oz. in the front to balance. It should balance at 2.5 inches from the leading edge. At that weight I will be pushing the 3lbs mark, which will push me out of the 100 watts per pound mark that I am wanting to keep. Does anyone have any idea what I could do? Thanks for any help.........GW

There are a bunch of guys there flying this plane as a electric conversion. I thought I read somewhere there that the guys were talking about re doing the tail out of lighter materal. If yours is already epoxied in place, maybe you could make some large holes in it and re cover to loose some weight.

CTD

jonnyjetprop
11-09-2005, 10:33 PM
Any chance of cutting a hole in the firewall and moving the battery further forward?

John

Gullwing
11-09-2005, 11:40 PM
CTD I don't know how much lighter I could make it. There is not much structure back there anyway. They had to keep it light so it would be in spec with the AMA scale event 750 class. But thanks for the idea. I could drill holes but I am afraid it is already too fragile as it is..........
Jetprop. I thought about the firewall thing it would be tight I think I would lose too much strength. See what ya'll think of this.........this is kind of on the movement of the battery.. I could cut an aluminum plate the size and shape of the firewall, cut a hole in the firewall and the plate for the battery to come through and attach the plate to the firewall. That might keep the strength of the firewall up to spec..........I don't know let me know what ya'll think...........Thanks alot for the replys...............GW

flyranger
11-10-2005, 01:31 PM
I saw in another board, a thread where a conversion ended up with the battery inside the cowl directly underneath the motor. Battery changes were done by taking off the cowl. Yes, the firewall would be modified, but maybe this will be a solution for you? The battery extended slightly back through the firewall, but was mostly in the cowl area, supported on a small shelf (and the extra hole in the firewall). The builder mentioned this also helped with cooling the battery. He also put the esc in there.:rolleyes:

chute42
11-10-2005, 11:58 PM
I just saw one of these last week. The guy cut a hole in the firewall and let the battery pertrude to the rim of the cowl, in fact he used two batteries in p with one on top of the motor and one on bottom.
I have converted a few planes myelf, and for the most part I cut the firewall a lot! Dont worry about strength, they are over built for vibration for IC motors.
Chuck

Gullwing
11-11-2005, 01:02 AM
Ok I am going through with it. I am going to cut the firewall....I am however reinforcing it for my own peace of mind. Thanks to all, here are a couple of pics of the progress so far. I will let you know how it goes. I am going to go with mounting esc inside the cowl for cooling.

Gullwing
11-11-2005, 02:19 AM
Ok here is the totals, finished the firewall mod. With the battery pushed as far forward as possible all I had to add was 1.5 oz of weight. Total AUW will be 44oz. I think that will keep me close to the 100 watts per pound mark I was shooting for. I have a few other details to finish on her. As soon as I do, and the wind dies down in the next few weeks I hope to maiden her. I will let ya'll know how it goes.....Thanks again for all the help................GW

Gullwing
11-13-2005, 01:12 AM
Got the power system in and balanced. Here is a pic.....

Gullwing
11-13-2005, 03:25 PM
Used my wattmeter, this setup gives alot more power than the motor calculator I use. Watts are supposed to be 273, meter says 307. Drawing more than 40 amps too. I dropped down to a 9X6E, and still producing 290 watts at 34 amps. Test running the motor in the plane, it was hard to hold the plane back. I will maiden it on this setup and go from there....GW

Crash Test Dummy
11-15-2005, 05:52 AM
Gullwing,
It's lookin very nice. My buddy just got one of these 2 days ago. I was at his house drooling all over it. Very nice looking ARF. I cantr wait to hear how your flys. Do you have a video cam?

CTD

Gullwing
11-16-2005, 12:09 AM
Thanks CTD. I have had it for so long and just waiting to get the power system in. It has been driving me crazy. I have not had the time or money to finish it. Everytime I do one of my daily flyers need repairs$$$$$
I think it will fly nice, the trust and watts say it will scream. I guess we will see. I will video the flight. I video most of my flights for two reason. One I learn by watching them, and two if I put it into the ground I have really cool video for the crash forum.....LOL .......I will let you know how it goes as soon as I talk my wife into launching it and the weather clears up. She has this thing about throwing 600 bucks into the air.........LOL............GW

Crash Test Dummy
11-17-2005, 06:40 AM
Thanks CTD. I have had it for so long and just waiting to get the power system in. It has been driving me crazy. I have not had the time or money to finish it. Everytime I do one of my daily flyers need repairs$$$$$
I think it will fly nice, the trust and watts say it will scream. I guess we will see. I will video the flight. I video most of my flights for two reason. One I learn by watching them, and two if I put it into the ground I have really cool video for the crash forum.....LOL .......I will let you know how it goes as soon as I talk my wife into launching it and the weather clears up. She has this thing about throwing 600 bucks into the air.........LOL............GW

Thats funny:) ! Throwing $600 bucks in the air can be scary. I read a quote one day and it went like this...........The art of flying is the ability to throw one self at the ground...................and miss!! I really liked it when I read it, so i comitted it to memory. I don't have the funds for one of these now. But maybe in the spring. I really wish they had gear from the factory.

I'll be waiting to see the video.

CTD

Gullwing
11-21-2005, 03:28 AM
CTD, I think I got around the wife throwing the plane issue. I built a launch carriage. I saw a guy on some website with the same Corsair only glow with one. I built it for less than 30 bucks. What do you think? I can't wait till the weather(wind) gets better to try it out..........GW

Crash Test Dummy
11-21-2005, 04:56 AM
CTD, I think I got around the wife throwing the plane issue. I built a launch carriage. I saw a guy on some website with the same Corsair only glow with one. I built it for less than 30 bucks. What do you think? I can't wait till the weather(wind) gets better to try it out..........GW

Looks good. Let me know how it works out. My buddy needs something like that for his FA-18 EDF Jet. He is pulling 600 watts at 42 AMPs!!!
Good luck, or I mean break a leg.:D

CTD

drksyd
11-22-2005, 06:01 AM
This is currently my favorite plane. I first had a 2820/12 in there but the 9x7.5 was too much for it. Now I have a Mega 22/20/3E spinning a 9x7.5 with power from a TP 3S2P 2100 PL. No problem hand launching with over 400 watts.
Have someone launch it for you, once you see how it goes you can throw it yourself. The 2808 will fly it, one of the guys here flies his GP P-51 with one and it flies. I personally like it with more power, actually the 2820 and Mega 22/20/x series are closer to .25 applications.

Gullwing
11-26-2005, 01:04 AM
UPDATE...... The launcher is going to work. Tried it out on the driveway, but probably not going to use it. As I was lifting the plane off the launcher one of the wings cracked. Now bare in mind this plane has never been flown or dropped. I peeled back the covering and found that it was flawed. I am so glad it happened now and not in flight. So here is what is going to happen......I have to repair the wing, so I might as well install retracts, and if I'm doing that by adding weight I will need a larger motor. So in the next few months(winter) I will buy an AXI 2814 and finish the plane the right way. I bought a J3 Piper yesterday for the AXI 2808. I have been wanting the Piper for awhile and this gave me a good reason to buy it. This motor will fly the Piper very well so I'm told..........GW

Old Fart
02-14-2006, 10:01 PM
Gullwing, any update?

Gullwing
02-15-2006, 01:32 AM
Nope I haven't had time to mess with it. It is so windy I am into my Tmaxx truck right now. I will let you know when I get it in the air....Thanks for asking.........GW

enrique1123
04-21-2006, 05:12 PM
UPDATE...... The launcher is going to work. Tried it out on the driveway, but probably not going to use it. As I was lifting the plane off the launcher one of the wings cracked. Now bare in mind this plane has never been flown or dropped. I peeled back the covering and found that it was flawed. I am so glad it happened now and not in flight. So here is what is going to happen......I have to repair the wing, so I might as well install retracts, and if I'm doing that by adding weight I will need a larger motor. So in the next few months(winter) I will buy an AXI 2814 and finish the plane the right way. I bought a J3 Piper yesterday for the AXI 2808. I have been wanting the Piper for awhile and this gave me a good reason to buy it. This motor will fly the Piper very well so I'm told..........GW
You will like it with the 2814/12 once you get around to it, I set mine up with 3s2p TP 1900 and an Eflite 40 amp esc and it flies great with a 10x7 prop. I don't go full throttle, it's too much. I did not install landing gear instead I have skids on the lowest part of the wings and land on grass. I put the batteries in front of the firewall and it balances ok. Hand launching is a bit hairy sometime but it's a lot of fun.

enrique1123
04-21-2006, 06:15 PM
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This is what I get with motor calculator and it very close, the stats for AXI arr very conservative I always push them very hard. The 2814 I am using is over 3 years old I think and it has flown several airplanes.

Old Fart
05-18-2006, 09:16 PM
Update - I went with a Fiegao 4750kv motor and a 4s 2500mah lipo, mounted under the engine mount. Converted the cowl to "twistlock"

Balances on CG with ZERO added weight :)

Can't tell you how she flies yet, waiting on a pilot and some aileron cover tubes - but if Motocalc is anywhere near correct - 70mph+

drksyd
05-19-2006, 08:30 AM
I'm not sure if it's just me but in the second pic it looks like you have it set up with left thrust.

Old Fart
05-19-2006, 02:47 PM
drksyd,

I centered the output shaft over the original marks -yes, they're to the left.

drksyd
05-22-2006, 10:34 AM
Have you flown it yet? Wouldn't you want right thrust to counter the torque? I'm quite sure the firewall is set with right thrust from the factory.

Old Fart
05-22-2006, 06:33 PM
I haven't flown it yet - but every one I've seen a picture of online (plus the photo's in the instruction manual) have the marks centered just like mine - off to the "right" as you're facing the firewall. Looking at the manual - the glow engine is supposed to center the same way.

Old Fart
05-27-2006, 06:01 PM
Flew yesterday - no thrust angle issues.

Did, however have an issue with overheating the ESC :(

Gullwing
05-27-2006, 06:56 PM
No No say it ain't so.......Man that sucks.......Looks repairable though.......GW

Old Fart
05-27-2006, 07:30 PM
Wish I could say - but it is so :(

I'll save the fuse - but ordered all the replacement parts today for less than $50

Also ordering an E-Flite Power 25 for it later today - that Fiegao ran way too hot.

Gullwing
05-28-2006, 01:49 AM
Yeah I am changing my AXI to the Power 25 as well. E-flite took all the guess work out of the motor thing.......Hope it goes well the next time you get to fly her...Let us know.....GW

Old Fart
05-30-2006, 10:17 PM
Well, at least I have a happy "before" picture!

dusmmdb34
05-31-2006, 06:19 AM
How is this one flying? yesterday I watched two buddies maiden two GP P51s. All I can say is wow!! One was on a axi 2810 the other on a inexpensive venom motor. The Axi powered one was a beautiful flyer with good power on the 3s 4000. The venom powered bird was simply raw power. He had it going so fast the wings started fluttering. It made everything else on the field look like it was standing still.
Today I went and picked up this $45.00 motor and plan to put it in either the P51 or the Corsair.....................I am simply trying to pick.

Old Fart
05-31-2006, 04:38 PM
Look at post #29, that was flight #2 :(

Up until that point - she flew GREAT. And she will again, Tower just shipped the replacement fuse today. Just need to pick up an E-Flite 25 on the way home.

Eplane65
09-01-2006, 04:09 PM
Here's my setup:

Motor: AXI 2820/10
Battery: Kokam 3S1P 3200
ESC: Phoenix 45
Prop: APC 10X7
Weight: 2 lbs, 14 oz (you figure in grams if you want to)
Power: It pulls 440 watts at 42 amps according to my Whattmeter.

I cut away the bulkhead so that I could mount the battery against the firewall. The ESC is mounted on the firewall next the to the motor so it helps balance and gets adequate cooling. I still had to add two oz of lead and screwed it to the firewall near the motor.

This thing flies great. It's very fast and smooth. I have no complaints except the covering keeps wrinkling.

AFG_Crusader
12-18-2006, 09:49 PM
I followed Eplane's setup
Axi 2820/10
TP 4000 3s
10x7
it flew right out of my and and has plenty of power. It looks great except the covering is wrinked. I tried to iron it out but it only took some of the wrinkles out. I think I might get a 2nd 1 and glass and paint it in f4u4C colors. I'm happy with the way it flys and would recommend this plane to everyone who loves Warbirds!http://www.wattflyer.com/forums/attachment.php?attachmentid=20431&stc=1&d=1166478450

Slowjohn
02-02-2007, 03:56 AM
Hello all,
I'm building this Corsair also and have run into a different problem. My kit is missing the "Cowl Ring". Is it nessasary? If so could one of ya'll post a drawing of it with it's dimensions. Also wondering if it's egg shaped or is it round?
Thanks for any and all help,
John

AFG_Crusader
02-02-2007, 08:48 PM
I hate when that happens! I ordered a funtana90 last year and im builing it right now and discovered both wings have damage 1 is gonna need to be recovered:>(. Anyway, the ring fits VERY tight inside the cowl and has 4 points that dip down and screw to the firewall. I would 1st call Tower and see if they will send 1. If not I would go to your LHS and see if they have that arf and trace that. Good luck

Slowjohn
02-02-2007, 09:24 PM
Tower Hobbies didn't seem to care as it wasn't a piece that carried a price but I was able to talk to a nice man at Great Planes and he sent me out one today. Just wish I'd of gotten his name so I could thank him here. Saved me a long drive to a LHS which is around 3 hours away. Small towns do have their drawbacks.

Now if USPS would stop losing my money orders, 4 in 6 months time. Had one small package that took 13 days to get to me and it was only a 3 hour drive to start with.

AFG_Crusader
02-03-2007, 12:28 AM
OK, thats good to hear. If you need any help with setup or something let me know. Also, I will take Tower over their major competitor (not talking about Hobby Lobby) anytime!

Old Fart
02-03-2007, 01:47 AM
I had similar problems with Tower when I ordered a replacement fuselage - the phone staff is only as intelligent as the screen in front of them :(

Once you get the replacement cowl ring - trace it and put the copy someplace. If you ever order a replacement cowl - guess what - the ring does not come with it :eek: (nor does the tail cone). For some reason the lower part of the wing that follows the fuselage does come with the fuselage, although it should come with the wing..........:confused:

Miner flies outstanding on the Power 25, 12x6 and a paralleled set of 2100/3S/15c's (need the nose weight, might as well make it work).

Bought my buddy the GP Combat Mustang - quite a bit faster (But still only a Mustang) :D

Slowjohn
02-03-2007, 02:29 PM
Thank Ya'll for the tips and info. I took about a 28 year break or so from the hobby and got a shock and a half when I started back into it a little over a year and a half ago. Biggest shock I guess was what was considered "cutting edge" back then is now called "Vintage". That made me feel the years :(! However I'm having a great time playing catch up :D!!!

Thanks again,
John

Old Fart
02-05-2007, 08:35 PM
Thank Ya'll for the tips and info. I took about a 28 year break or so from the hobby and got a shock and a half when I started back into it a little over a year and a half ago. Biggest shock I guess was what was considered "cutting edge" back then is now called "Vintage". That made me feel the years :(! However I'm having a great time playing catch up :D!!!

Thanks again,
John

I hear you John - I took a 30+ year break myself, only the advent of Lipo's and the current electrics got me back in - but only with 2 maybe 3 planes tops!

Yeah, right :p Two years later I've moved on from my pair of Optic 6's to a Futaba 9C just to get enough memories (and aileon differential on elevon ships)

Here's Friday's fleet - half a dozen more at home :)