twistr

My Feedback: (4)

I just picked up this plane on a trade so so far I'm out no cash. It's in excellent condition but no motor. I was thinking about the Zenoah G-45. Will this be enough power for this bird? I'm going to put a full smoke system in her too so I want to make sure I have enough power to pull her out of trouble if need be. I've looked at several other motors out there but they're all very pricey. Zenoah looks to be the most inexpensive.

Anyone ran this motor/plane combination have any feedback?

jongurley

My Feedback: (29)

We had the Christen II and we put a 35cc gas on it,, NOT ENOUGH POWER. I wouldn't go any less than the 45,, if you are going to run smoke you still should be fine,, if you can get the motor at a deal it will pull it great ,,,, Go for it,

scotsman212

I used a G-45 with a Brison Pitts smoke-muffler in the GP Pitts. Unless you want to absolutely trash the fiberglass cowl by cutting it to pieces so parts of the engine can stick out all over it, (ugly, ugly, ugly[:'(]) here's what I did. (1) I bought the prop shaft extention for the G-45 so the engine could be moved back further into the cowl toward the firewall and to a wider, more roomy area of the cowl... but (2) when you do that, you have to cut away the bottom of the firewall to clear the Brison smoke-muffler for cooling purposes.

That's when I engineered the motor mounts I gave a "seminar" on in one of my earlier posts. (I cut that stupid engine mount box totally off and smoothed the firewall.) By cutting the extention "tubes" to the precise length, I was able to position the engine just where it needed to be. That is: prop hub just past the front of the cowl and Brison muffer against the firewall. The bad news is, to do it right, one must now "re-engineer" the bottom 1/3 of the firewall. The good news is, there's room to do that. Just be carful to reinforce the firewall again after you make the "step-in" to clear the muffer. I angeled the top of the step-in to facilitate and direct air-flow around the top of the muffler. If you wanna get fancy, you can use a block of balsa and radius it to match the radius of the muffler plus a half-inch and trim the back-side for weight.

Yes, it is some extra work and you need to have a "little engineering ability" to pull it off but it's not that difficult. I will say this about that... a Dremel Tool is a good thing to have here. What you need to do becomes obvious as you progress into the project. Just cut the hole you need for the muffler to clear then set about to "frame back in" around what you've cut out leaving room for the necessary clearence around the muffler. Just not that difficult. Once you've cut out the hole in the bottom of the firewall, its easy to see and get into the areas where you need to "beef-up" before you close it all back in and finish it off. This is also a good time to locate and do the necessary framing to hold the smoke fluid tank(s) inside the firewall. This also adds to the area for engine air to escape out of the cowl and forms additional vacuum inside the cowl, especially during flight at speed. (Air-flow over a venturi will cause a vacuum at the other end of the venturi which is the effect of the additional opening around the muffler. Air passing over the underside of the cowl and the muffler "opening" will set up this "venturi" air-flow or vaccum inside the cowl pulling out additionl engine heat from prop-wash alone.)

It makes for a very cool looking installation with the two downward pointing exhaust ports sitting just about right. Where GP provided stick on "mesh" for the cowl "openings", I cut out the openings. I don't know about the cowl on the Christen... if it has sufficient ventelation around the rear edge area where it overlaps the fuse as it does on the Pitts. I also added a full around former at the right distance from the back edge of the cowl so I could mount the cowl with a long "star" wrench and screws through the front intake ports of the cowl without having to punch a bunch of screw holes round the outside edge of the cowl just back of the firewall.

Here's a tip: Drive the screws into the firewall at the best straight-in angle for the wrench so you don't need a ball-end or whatever. They don't have to set perfetly flat and straight since they're invisible after install. For best results, use a flat washer under the head of the screw and under that, a rubber washer from a metal roofing nail for a good tight install.

The choice of the "gas" engine means you don't even have to cut a hole in the cowl for the needle valve to stick through. I guess whackin' holes in the cowl doesn't seem to bother some peope but it bothers the heck out of me. Both of these aircraft, the Pitts and the Christen are addmittedly "semi" scale but I see no reason to "butcher" them up any more than is absolutely necessary.

The weight of the airplane with this engine, smoke-muffler and smoke-oil tanks is not light but should still give scale performance. I've never seen a real Pitts hang on the prop or do 3-D manuevers anyway. If my Pitts will fly like the full scale, I'll be extremely happy with its performance!

I have yet to run the engine in its present config so when I do the test run-up, I'll monitor the engine temp and if necessry modify the edges of the firewall (out of sight under the back edge of the cowl) to give extra clearence for cooling air. But this mod is very unlikely with the extra clearence around the step-in for the muffler. Whatever it takes to keep from whacking on the cowl so it looks like a giant sieve or looking like it is plagued by giant "engine warts". If it matters to anyone I can post some pics of the completed installation as I've described it above.

Another tip: If you are a novice builder, projects such as this can prepair you for a number of sticky issues as you progress in you building abilities. If you are not presently involved in any project even similar to this, think through how YOU would do it maybe using some of what's been suggested here. With a little practice and a tad of good ol' American ingenuity, you'll discover you can do just about anything you need to do to make a project finish out the way you want it!!! Hope all this helps someone.

JohnnyJ

My Feedback: (1)

Hello,
I had(my friend is flying it now with a G62 in it) a Byron Christen Eagle that flew well at 21lbs with a G45 on CH ign on it.
The vertical wasn't great and it wasn't a floater. I did have fun with it and it looks good in the air.
Not that hard to land 3-point either!
I modified the muffler similar to the one in the photo and the G45 turns a Bolly 22x10 at 7100 rpm.
I am planning on a GP Christen Eagle now and it should come in at 3 or 4 lbs lighter with the G45 on CH ign.
Flight performance will be greatly improved and the fun factor will go up a bunch.
Good Luck!
John

scotsman212

Looks good. I just get a little uneasy with a hot muffler that close to the ply. May be that it's nothing to worry about but it really bothers me so that's why I go the extra mile to keep it safe. As I mentioned, the additional venting of engine heat is a consideration too. Have you ever checked to see how hot that engine box gets just after a flight? As it sets right now the muffler on my Pitts bearly touches the bottom of the firewall and it really bugs me. What are your thots on the muffler heat?

JohnnyJ

My Feedback: (1)

The paint I used to seal the wood is not getting "cooked" so the temps should be ok!
Good Luck
John

gadix

My Feedback: (2)

brison 2.4; fuji32, DA 50 will do fine and enough for 3D

Volfy

My Feedback: (23)

3D with the Christen Eagle?! Surely you jest. Fuji 32 is nowhere near enough; 50 or 64 should be a better match. One advantage with the Fujis is that the firewall to prophub distance is the right 6.5" for the GP CEII. The 50 will hide completely within the cowl. However, the BCM wrap around Pitts for the Fujis still interfers with the lower part of the firebox. But it is easy enough to hack a notch into it for clearance.

The G45 is a good match, though the G62 weighs and cost almost the same.

jongurley

My Feedback: (29)

You Can't 3d a Christen,, very aerobatic but not 3d capable,,

scotsman212

Yup! I can't imagine even wanting too... so out of character for that beautiful little aircraft! It needs to be flown gracefully and deliberately... IMHO...

thevirginian

twistr;
I have a Fuji 50SB in mine and it flies O.K. By that I mean it does all the IMAC-maneuvers you want but no 3D. She is no 3D bird, period. I tried a G-38 in mine while I was waiting for my Fuji to arrive. It flew it but very marginal. A G-45 should do better but you may have to deal with installation issues. The Fuji 50 fits perfectly within the cowl and the stock muffler exhausts thru a hole on the bottom of the cowl. Also the length is matched. No spacers required. I installed a 20x10 Mezjlik on mine a couple of month ago. Mine turns 7100 with this prop and the performance increased drastically over a wooden prop. Now, if you want to spend more money than go and buy a Brison 3.2 or the equivalent FPE. Both are very powerful motors and exellent choices for this beautiful bird.

Lowlevlflyer

My Feedback: (3)

You say the Fuji BT50 fits in the GP Christen with no spacers at all? I would have figured that the firewall forward on this plane was the same as the GP Pitts. When MAN did the review of the Pitts, the Fuji 50 engine was used, and the author had to use the optional prop shaft spacer to get the correct spacing between the cowl and spinner. Didnt figure there was that much difference in the two models.

Volfy

My Feedback: (23)

Earlier production Fuji 50 came with a prop hub that made the mounting surface to prop distance = 7.0in. Fuji made a running change later on prop hub that shortened it somewhat. The elec. ign version of Fuji 50 = 6.5in, which is the one you really ought to get anyhow.

Lowlevlflyer

My Feedback: (3)

Ah, I see. Thanks for the clarification.

thevirginian

Go download the manuals from the GP website. You'll find a page where the Fui installation is described and shown with pictures.

Claselva31

My Feedback: (8)

thevirginian,

I am getting ready to purchase the engine for my GP CEII.I was headed for the Fuji 50EI.One of my goals is not unlimited vertical but darn near it.Plan on a smoke system.What kind of servos did you use?I was planing on HS5745 Digitals and something bigger for the rudder.I contimplated the BT64Ei but was afraid it would shake the plane apart?Any help or comments Please> Chris

twistr

My Feedback: (4)

Clasey:

I went with a Brison 3.2 Great choice and it flew great with it but saw an early demise as I watched the top wing burst into splinters in mid flight. Don't know what went wrong it just came apart in flight. I have since put my brison 3.2 in a GP cap 232 27%. Still learning to fly it but boy do I miss my christen eagle. I'll have another one someday!!!

Volfy

My Feedback: (23)

I have both 50EI and 64EI and personally I would definitely not use the 64. Not so much because the vibration. The bigger thumper does shake more, but as long as you balance the prop well and make sure runout at the prophub is not too bad, it should be no worse than any other big 60cc single. The main reason is esthetics. The 64 has a shorter mounting surface to prophub distance: 5.5"(?) if I remember correctly. This means that you not only have to put a spacer block or standoff to get the correct 6.5", the engine cylinder will stick way out front and definitely be poking out of the cowl. I'm usually not that fussy about cylinder head sticking out the cowl bottom, but the CEII is an exception.

As for power, my experience is that the Fuji 50EI should turn at least 7000rpm with a 20x10 prop, which should be good - not great - for a 16-17lbs CEII, as long as you don't load it up with smoke system and such. If you want "darn near unlimited vertical" 18+lbs all loaded up, then the Fuji 50 (really a 46cc) is not for you.

I've had my GP CEII sitting 1/4 finished for more than 1yr now. I just don't have much time these days to play RC anymore. I came close to wanting to sell it as is, but now that I have a cargo van that can fit an airplane with 69" wingspan without disassembly, I think I'll keep the CEII. Having the big beautiful bipe ready to go as soon as I pull it out of the van would be very nice.

Aeromove

Still interested in answers?

I've got this combination on my GP Eagle II.
Want some pictures? It fits very well in the cowl.

Regards,

Thierry

airborneSGT

My Feedback: (15)

I had an FPE 3.2 on mine. Used an NX 22x8 and was happy. There was a dude on RCU who was serisouly torque rolling and doing some elevators with his. Maybe I should get another Eagle to beat on. Very fun but 3D dont think so.

On the other hand I have a Frank Knoll Christen Eagle I might buy and build with a DA 100. I know for a fact that it will 3D.
I think the best ARF for an Eagle right now is the SkyShark offering.

Rcpilot

My Feedback: (78)

Fox 3.2 on my Pitts. NX 22-8 prop.

I completely cut the firewall and motorbox off the front of the plane. Sanded the front of F2 flat. Then I went in and cut 1/8" wide slots in F2--right next to the existing motorbox sides. Rebuilt the entire motorbox with 1/8" hard aircraft ply. New firewall from 1/4" hard ply. Tri-stock everywhere.

There's some decent pics of my surgery in the GS forum somewhere. You can do a search for my name as the topic starter, and put GP 1/3 Pitts Assembly in the search box.

It was a royal pain in the butt, but I'm happy I did it. That stock motorbox was made from some of the flimsiest 1/8" cardboard I've ever seen. There was no tri-stock anywhere. I put tri-stock on the back side of the F2 former to keep it from ripping out. I ran the top and bottom of my motorbox all the way back to F3--just like the motorbox sides. Stock, the top and bottom of the motorbox is simply tabbed into F2 and it stops right there. I ran mine all the way back to F3 and tri-stocked the heck out of it.

When mine crashes--I expect to find a pile of toothpicks, and a motorbox thats undamaged.

EDIT:
Here's that thread with the pics of my motorbox modifications. The good pics start around post #20.
http://www.rcuniverse.com/forum/m_3862205/tm.htm

airborneSGT

My Feedback: (15)

I rebuilt my turtle deck so I can also back you up on the flimsy motor box. I was quite shocked at the lack of any good structure. Its really worth the effort to re build it. I was hoping to find out where all the weight came from. Even with lightweight and CF stuff I think I was a little over 17lbs!

Rcpilot

My Feedback: (78)

I know. This thing is built like flimsy as hell, but it weighs a ton. I can't figure out where all the weight came from. The wings feel heavy to me, but they can't be the only factor in the weight of these planes.

Can you imagine how heavy they would be if GP actually designed them the right way with blind nuts on the main gear, and tailwheel? Blind nuts where the center cabanes bolt up to the fuse? And blind nuts in the wings for the outer cabanes?

I think the reason why there are so many of those stupid wood screws in this plane is because they had a serious weight problem, and the wood screws was an easy fix. Compare the weight of a #4 wood screw to a good bolt and blind nut combo. That would have added another 1/2 pound to the plane.

I replaced all of the stupid screws except the ones in the wings. It made me mad as hell, to see that plane put together with wood screws, but I wasn't going to tear into the wings to replace them with 4-40 blind nuts. I did tear the fuse apart and put 4-40 blind nuts where I could. Even tore open the back and installed blinds on the tailwheel. It was all a ton of work, and the plane took me like 2 or 3 months to assemble it. But, it sure do fly sweat. [8D]

airborneSGT

My Feedback: (15)

I think the design flaw is in the top wing amongst aother things. On other bipes I have flown like the DP Ultimate, WH Ultimate, Cermark Pitts, and the Skyshark Eagle they had a much better way to mount the top wing. All of them mounted the top wing to the cabanes in a very similar fashion. It also help up and actually worked well. The same cant be said for the GP eagle. I cant even begin to remember the number of times I broke my cabane mounts or striped the screws out of the wood.

Just talking about this makes me want another Eagle!

maticeci

for this kit, can work with smoke system and G62 or is better DA50 ?