NeeI am rebuilding a christen eagle by cox does not look in too bad a sd help or info

[Gofer303]

I am rebuilding a christen eagle by cox does not look in too bad a shape had to replace servos for tail both were bad the motor is brushless and has a esc all unmarked but working. Any info on cog battery placement or any info at all is appreciated and I thank you in advance.
Larry

[CHELLIE]

Originally Posted by Gofer303

I am rebuilding a christen eagle by cox does not look in too bad a shape had to replace servos for tail both were bad the motor is brushless and has a esc all unmarked but working. Any info on cog battery placement or any info at all is appreciated and I thank you in advance.
Larry

Hi Larry You can use the following to find the CG of any biplane or even monoplane for that matter. First treat both wings as one: ie if the wings are 6" chord and the top wing is 2" ahead of the bottom, then that's the same as a 8" chord. use 25% back from the front wings leading edge, thats a safe place to start from. you can them move the cg back and find the sweet spot, 30% might be to much on some planes, so use 25% to start with, a nose heavy plane will fly, but a tail heavy plane will only fly once

http://www.rcgroups.com/forums/showthread.php?t=1305044

[Gofer303]

Chellie I did not know how to do that and figured the easiest way to find out is ask. That will work out good as I have a cog balancer that was donated to me due to the size of the persons planes were way too big for it. If I can find my camera that was "borrowed" by one of the kids for a day last week will get some pics up. This plane had been flown but shows no great damage dings etc the servo tray was chewed up and as integral part of the body and just foam I made a balsa tray which is real light and glued that to the remaining foam. I really need to get back to the Mud Duck Build that has been on hold due to a lot of other problems and the lack of $$$ for finishing the motor set up but now am announcing again so in 2 months of saving it will get up in the air.

[CHELLIE]

Originally Posted by Gofer303

Chellie I did not know how to do that and figured the easiest way to find out is ask. That will work out good as I have a cog balancer that was donated to me due to the size of the persons planes were way too big for it. If I can find my camera that was "borrowed" by one of the kids for a day last week will get some pics up. This plane had been flown but shows no great damage dings etc the servo tray was chewed up and as integral part of the body and just foam I made a balsa tray which is real light and glued that to the remaining foam. I really need to get back to the Mud Duck Build that has been on hold due to a lot of other problems and the lack of $$$ for finishing the motor set up but now am announcing again so in 2 months of saving it will get up in the air.

It will be great to see your Mud Duck in the air Yea I know about the $$$ part, i am retired and live on a fixed income, and really have to budjet myself, thank goodness i was able to pay off a lot of bills and such before retiring, Take care, Chellie

[Gofer303]

Revisiting this post and still have not heard from any one what throws were for stock set up. Any info appreciated.
Larry

[kenchiroalpha]

Hi Larry
Pleased to meet you
These links may be of help
http://www.rcgroups.com/forums/showthread.php?t=616587
http://www.rcuniverse.com/magazine/p...ert.cfm?id=807
Take care
Yours Hank

[Gofer303]

Ken your a friend indeed thanks great info but does not list the control throws. I need a owner who has the manual for it to copy me the throws and other set up info not listed online. The plane has been rebuilt and new parts and servo installed and even tested on a short taxi. I really do not want to guess the set up on this plane.

[Gofer303]

Hey all I have had some time and energy all at the same time and put together the Cristen Eagle. wings are roughly 6.25 inches wide so as per Chellie's suggestion I figured the cog at 25% and it seems to be almost spot on balance wise not quite a down angle but not tail heavy either. The problem is with the stock position for the battery is behind the motor and in front of the wheels. There seems to be a major problem with this. The plane on the ground is so nose heavy it will tip forward when the prop starts getting some speed up. I have been thinking on using different wheel sets but these are stock set up and if I move the battery back the cog is very tail heavy. I almost took it out and hand launched it and the hell with the landing but it is a good looking plane and I dont want to ruin it. When got it on a auction it went cheap and now looking at the repairs I had to make this has been its problem all along. This is a Cox Christen Eagle arf no longer made and I have never been able to get a hold of a manual. Any suggestions welcome Thanks in advance.

[CHELLIE]

Originally Posted by Gofer303

Hey all I have had some time and energy all at the same time and put together the Cristen Eagle. wings are roughly 6.25 inches wide so as per Chellie's suggestion I figured the cog at 25% and it seems to be almost spot on balance wise not quite a down angle but not tail heavy either. The problem is with the stock position for the battery is behind the motor and in front of the wheels. There seems to be a major problem with this. The plane on the ground is so nose heavy it will tip forward when the prop starts getting some speed up. I have been thinking on using different wheel sets but these are stock set up and if I move the battery back the cog is very tail heavy. I almost took it out and hand launched it and the hell with the landing but it is a good looking plane and I dont want to ruin it. When got it on a auction it went cheap and now looking at the repairs I had to make this has been its problem all along. This is a Cox Christen Eagle arf no longer made and I have never been able to get a hold of a manual. Any suggestions welcome Thanks in advance.

Hi with the supplied 1800mah lipo the Cg is suppose to be right on,, the art tech bi plane is the same as the cox from what i understand and have tried to find CG info on that too,

http://www.art-tech.cn/english/Artic...?ArticleID=134


http://hobbyking.com/hobbyking/store...dProduct=10102

i think this HK bi plane might be a art tech bi plane also known as the cox christen eagle.

http://www.rcgroups.com/forums/showthread.php?t=1239061
check out post #2



May 04, 2010, 04:07 PM #2 SabreHawk
Off we go.............



Join Date: Jan 2006
Location: Seattle, WA. USA
Posts: 3,245


Just ahead of the rear bolt on the top wing's cabane strut attachment.
Here's a shot from the Christen Eagle's manual. This plane is identical, and even of the same manufacturer, Art Tech.
This image has been resized. Click this bar to view the full image. The original image is sized 904x482 and weighs 89KB.

[CHELLIE]

some people have had to cut the foam in the fuselage to get the CG correct by moving the battery

[Gofer303]

Thanks Chellie and Saberhawk. The cog using the 25% was really close to the info in the reply. If I chop a hole and move the battery back a tad that may fix the weight over the LG will have to try this. All the links look identical to the one I have even the tail numbers. This is the brushless model and it took me a while to figure the wing mounting I almost hated to screw in the back screws on the cabines. Well if everything works out today I will do some choping if it does not work then I have a motor esc to play with. BTW the last good battery I have is a 11.1 1300mah 30c and it seems that is the stock battery listed for this. Again thanks for sharing all of your experience with me I really appreciate the help.

[Glacier Girl]

Gofer here's the manual for it.
Not a mention of throws in it......

http://www.art-tech.cn/english/pdf/Christen-Eagle.pdf

[Gofer303]

GG Thanks for the pdf it is interesting how little information it contains. I must admit there is much less chinglish in it than I expected. Looks to be the exact same plane as I am trying to get to fly.