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Christen Eagle - Building, Alterations and Modifications

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Christen Eagle - Building, Alterations and Modifications

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Old 04-20-2015, 12:25 PM
  #751  
grassie
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Hi Guys. Good to see there is a thread on CE's. I have been looking for some info on incidence for this plane. I see in #261 there is a very unhappy guy. Well, I got a kit that is exactly the same. It seems like all the parts that didn't fit anywhere were put in a box and sold of to me.
First and biggest problem is the fact that the bottom wing does not fit the saddle at all!. I had to elongate the holes in the fuzz and sand away half of the dowels to get the wing anyway near setting in the saddles.
Well, to make a long story shorter, I maidened the plane but it was unflyable! How I managed to get it back on the ground in one piece is a mistery!
I changed the incidence quite a bit and took it out for another test flight, this time it flew better but still tucked heavily to the undercarriage in the knife edge.

I decided to land as I felt the incidence needed more attention. Thee approach was picture perfect but as soon as the wheels touched the runway, yes you've guessed it, it bounced and disaster struck. The plane tip stalled before I could say knife! The entire firewall came off, all 4 wingtips were damaged and the one horizontal stab broke. A perfect 5 point landing....

That is all history now, the damage is repaired and it is time to dig into the incidence again.

Now I have read this entire thread tonight and nowhere does anybody make any mention of incidence as most kits went together with little or no hitch. Has anybody perhaps measured the incidence on their plane and are you willing to share your info with me? Please, and thank you in advance.

I have installed a GP 61 on the nose of the CE swinging a 23 x 10 at 7500 rpm.
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Old 04-20-2015, 02:39 PM
  #752  
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Most bipes fly good at 0 degrees lower wing and 0 to 1/2 degrees negative upper wing. Sounds to me like you might have been a little fast on the landing.
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Old 04-20-2015, 02:45 PM
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I don't know what mine is but it would be easy enough to measure it as I leave the plane assembled and transport it that way. I find mine pushes to the bottom a little in knife and also tends to nose up a little when inverted. I suspect this one is a little tail heavy with only an OS 160 in it. It rolls beautifully, loops ok but not enough power for big loops. I like it a lot though but don't fly it often enough. I'll get out the incidence meter and check. It was used when I bought it and I never checked. I probably should. I might add that it is one of the nicest landing bipes I've tried and slows down more than I would have expected. It took me several tries to get used to it but is quite graceful on landing.

Rick H.

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Old 04-20-2015, 10:25 PM
  #754  
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Originally Posted by 308jockey View Post
I don't know what mine is but it would be easy enough to measure it as I leave the plane assembled and transport it that way. I find mine pushes to the bottom a little in knife and also tends to nose up a little when inverted. I suspect this one is a little tail heavy with only an OS 160 in it. It rolls beautifully, loops ok but not enough power for big loops. I like it a lot though but don't fly it often enough. I'll get out the incidence meter and check. It was used when I bought it and I never checked. I probably should. I might add that it is one of the nicest landing bipes I've tried and slows down more than I would have expected. It took me several tries to get used to it but is quite graceful on landing.

Rick H.
I would really appreciate if you are willing to do that. I have spent hours working on the incidence and it is still not right. Thanks in advance for your trouble.

@av8djc - Thanks for that input. I believe you might be right. Some say the bottom should be +1, top -0.5 and stab -1.5. I have seen some say 0 for all and then like you stated -0.5 top and the rest 0.

I would like to have it first hand from someone with a CE that flies well and lands like it should though. The repairs to my CE set me back a third of the cost of the kit. I would hate to damage it again. Oh, and yes, according to some bystanders I was a little hot on the landing....

Last edited by grassie; 04-20-2015 at 10:27 PM. Reason: forgot to say something
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Old 04-21-2015, 04:15 AM
  #755  
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I'll try to get that checked today, tomorrow latest. I can tell you that this is a very nice flying airplane, one I'll keep. Like I said it rolls beautifully and loops well too, snaps and spins are good. Landings are very easy, it doesn't drag in as much as most bipes, it's just cleaner aerodynamically but be careful and set it down smooth. It will bounce as you've seen. I think the landing gear is a bit springy personally and I wonder if there is a replacement for it somewhere. Let her slow down, it is well mannered at slow speeds. I wonder if the tuck in knife edge is connected to the dihedral in the lower wing. Not much to be done about it if so, just mix it out. I'm surprised that yours went together so poorly, I've not heard a lot about that with this product. I guess there are always one or two. As others have said, keep an eye on all the struts for wear, maintenance on this airplane will be key to keeping it in one piece. Anything else you want to know, I check in on this thread, glad to help if I can.

Rick H.
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Old 04-21-2015, 04:46 AM
  #756  
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Thanks so much for taking the trouble to help with this. While you are at it, do you mind checking the CG as well please and thank you.

Gerhard.
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Old 04-22-2015, 04:23 PM
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I checked the wing incidence this afternoon on mine and found the bottom wing with .25 degrees positive and the top wing has about 1.5 degrees positive. I don't recall where it balances, will check when I get out there tomorrow and let you know. I do recall though that when we first checked it, it was in the reccomended range but slightly aft of the center of that range. Still within spec but this plane sometimes feels slightly tail heavy for my preferences. I think if you balance at the front of the cg range you will have a good flying plane. In any case I'll look tomorrow and get back to you with an exact location.

Rick H.
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Old 04-22-2015, 08:31 PM
  #758  
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Thank you so much for the time and effort you took to help with my problem. It is sincerely appreciated. My Eagle has been sitting up on the wall for almost 6 months but this has me going again. It is coming off this morning to be shimmed. Lets see if this one will fly as well as yours.

I have been looking for another kit around these parts but they are like hen's teeth. Those that have them won't let go either.

Kind regards,

Gerhard

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Old 04-23-2015, 06:29 AM
  #759  
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Would you be interested in building from Plans Gerhard?
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Old 04-23-2015, 07:09 AM
  #760  
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Yes, definitely!
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Old 04-23-2015, 12:23 PM
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Check your PM box.
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Old 04-25-2015, 07:20 PM
  #762  
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Originally Posted by grassie View Post
Hi Guys. Good to see there is a thread on CE's. I have been looking for some info on incidence for this plane. I see in #261 there is a very unhappy guy. Well, I got a kit that is exactly the same. It seems like all the parts that didn't fit anywhere were put in a box and sold of to me.
First and biggest problem is the fact that the bottom wing does not fit the saddle at all!. I had to elongate the holes in the fuzz and sand away half of the dowels to get the wing anyway near setting in the saddles.
Well, to make a long story shorter, I maidened the plane but it was unflyable! How I managed to get it back on the ground in one piece is a mistery!
I changed the incidence quite a bit and took it out for another test flight, this time it flew better but still tucked heavily to the undercarriage in the knife edge.

I decided to land as I felt the incidence needed more attention. Thee approach was picture perfect but as soon as the wheels touched the runway, yes you've guessed it, it bounced and disaster struck. The plane tip stalled before I could say knife! The entire firewall came off, all 4 wingtips were damaged and the one horizontal stab broke. A perfect 5 point landing....

That is all history now, the damage is repaired and it is time to dig into the incidence again.

Now I have read this entire thread tonight and nowhere does anybody make any mention of incidence as most kits went together with little or no hitch. Has anybody perhaps measured the incidence on their plane and are you willing to share your info with me? Please, and thank you in advance.
Incidence being off a few degrees wouldn't cause the plane to be that difficult to fly. Sounds like you had a CG problem.

Try setting your bottom wing at 0 in relation to the tail, top wing at +1 and engine -2 with 2 degrees of right thrust. These settings must be precise in order to have a perfectly trimmed airplane at all throttle settings. Use a Robart incidence meter - not a digital one. On landing, you will want to fly the airplane until just before stall. Of course you will want to be a few inches off the ground at that point. If you try to wheel land with speed, you just end up bouncing down the runway and likely flipping over and breaking the tail!
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Old 04-25-2015, 07:54 PM
  #763  
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One thing I have noticed is the different incidence settings on aerobatic bipes. I have a Reed Falcon kit that will be started soon. The wings are both set to zero using the stab as reference but the engine has 2 degrees of up thrust. This is the same airplane that won the 1988 TOC so I have to beleive it flys well this way. Both the old Dave Patrick Ultimate and the Goldberg Ultimate ( both designed by Dave ) have both wings and engine set to zero but the stab is 2 degrees positive. For the most part, I have found that an aft CG will cause a tuck to the gear when in knife edge as well.
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Old 04-26-2015, 04:46 AM
  #764  
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The bottom wing is now set to +0.5 and the top is 1.5 with the stab at 0. I checked the firewall and it pretty much 0 down. I can,t remember what the right thrust on the firewall is. I still have to put the engine back so will get to that tomorrow (Monday). It is quite possible that the CG was to far back on both flights. Moving the weight forward and back does not make a big difference to the attitude of the aircraft when checking the CG. Maybe that threw me a bit. Thanks for the advise.
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Old 05-16-2015, 08:25 PM
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Grassie how did your plane fly? I got mine out today for the first time in probably a year. The engine lost compression and after pulling the head and cleaning it up I just didn't get back around to it. Took it out and after a minute or two of rough running all the goop cleared from the carburetor and she ran fine all day. Mine has an OS 1.60 in it, enough to fly well but hardly a 3d machine. As I said earlier it rolls beautifully. I forgot to add a little weight to the nose so it is still a little tail heavy for my taste but within the safe CG range. Some photos of it are posted here. Hope all is well with yours.

Rick H.
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Old 05-25-2015, 12:05 AM
  #766  
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Your CE looks great. Like stated previously, I did the incidence and have now fitted the engine. I still have to put the cowl back on but first want to make a mold so I can reproduce it if anything goes wrong. I want to do that with the spats as well and I might as well make a canopy too while I am at it.
I will get to that in the weeks to come.

Gerhard
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Old 05-18-2016, 09:06 AM
  #767  
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My CE is finally assembled again. now I just need to get to the field and have someone to give me a hand. It's been some time since I worked on my planes as the health is a big problem. Once again I would like to thank everybody for their inputs and advise.
Acerc, thanks I received your message and is looking into having a kit laser cut.
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Old 05-26-2019, 07:55 AM
  #768  
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Is there anyone that can make me new cabane struts out of high strength aluminum? I need 2 sets and I donít know how to go about cutting and getting them right. It is for the gp Pitts, but I understand the christen eagle is the same. Pm me if you think you may be interested. Thanks!
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