buzzard bait

Slim, I pulled out the plans you kindly sent to me and got out some engines to put up against the plan. My 40 FP would fit if you took out the shim and mounted directly to the firewall. I assume that means the LA would too, except you would need a small cutout for the remote needle. If you want the thrust offset you could grind down the shim so that it tapers to nothing at the starboard edge.

Another alternative might be to use a standard Dave Brown motor mount and cut out enough material between the arms, which doesn't have any screw holes in it, if you see what I mean. Then you could move the motor to the back and not have the thickness of the mount. It looks like this would work on the DB 4045 size mount. You'd be coming fairly close to the screw holes, but I think there would be enough meat left to have a secure mount (the DB 3035 mount also fits the OS 40 plain bearing engines, but if you cut it out there wouldn't be much left). You might even be able to grind thrust offset into the motor mount.

The other alternative is to get a TT .25 GP or an old OS 25 FP (or the even older 30 for that matter), or Enya 25ss or 30ss. Then there would be no problem with the mounting. You'd have to stick to the plain bearing 25-30s because the BB types are just as long as your 40 LA. An OS 25 FP is as strong as the old OS 30. With modern gear you'd still have a very good performer.

Jim

slim_pkns

Oh my God! I can't believe there isn't a back plate style mount for the OS .40 LA! WTH?! I find them for gas engines, but not glow.

What if I take off the nylon backplate and drill holes through the mounting block and firewall where they are located> Then get longer screws and just mount it that way using a good bit of Lock Tight so they don't vibrate out. That looks to be the way a backplate mount would work anyway except there are separate holes for mounting to the firewall rather than using the same holes for the backplate and the mount.

Bax

My Feedback: (11)

The kind of mount you're asking about just don't exist for glow engines...at least not any more. Remember, your kit was designed in the 1960's or so. Just use a mount like this one:

http://www3.towerhobbies.com/cgi-bin...&I=LXJ771&P=ML

buzzard bait

Slim, the reason for the aluminum plate is so you can get it off again, and tighten as necessary. If I understand your method, the screws are on the back of the firewall. When the wooden firewall compresses, as it will over time, how will you tighten them up again?

Jim

ARUP

Insert pins at different angles to remedy sheeting sliding up the pins. This is a pretty airplane. I've always wanted to build one. So many airplanes so little time!

Cherokee Flyer

Another mount that might work: http://www.mecoa.com/acc/mounts/edson/edson.htm

L.

slim_pkns

Thanks ARUP and thanks a lot everyone for the help and advice. I'm still not sure what I want to do yet. I don't think I've exhausted all ideas. In the meantime, I'm going to work on the rest of it until I'm left with a complete model with no engine if necessary!!!

I may have to design a new mount and find somebody to machine it. One that has 2 deg right and a little down already in.

slim_pkns

Howdy all! It's been a long, long time!

Work is finally slowing down a bit and I have time for hobbies now. I've been back to work on the VK Cherokee Babe! I left it alone on the building board for a couple of years while I struggled with an engine mount. I feel pretty stupid, but leason learned.... the metal plate that came with the kit IS the engine backplate mount! All I needed to do was drill holes for the screws and counter sink the backplate screws so it sits flush against the firewall and I would have been good to go. I ended up buying a Viper backplate mount from Great Planes before I figured that out.

Anyway.... the build is on and I'm already covering. I'll have some pictures to add this week. Hopefully the muffler I need will be in this week and I can finish her up before Christmas.

buzzard bait

Oh those old metal backplate mounts...you never see those anymore, no wonder you got thrown by it. They were popular around the 70s I think.

I won't be starting one soon, but I'm still glad to have the plans socked away. Our club is going to do a biplane event next year, so bipes are top on the priority list now.

Looking forward to seeing your Cherokee Babe get finished up!

Jim

dah1202

My Feedback: (1)

I know I'm a few years late to the party. HOWEVER I built a Cherokee Babe around 1971 and absolutely loved it. First with a Merco .29. Then I changed to an OS Max .35. We did not have a muffler rule back then and the OS Max .35 with the wiper over the exhaust had a stunning idle. I hope you completed your build and got a lot of joy from the model.

049flyer

My Feedback: (18)

Yes indeed they will spin! All the way to the ground. Mine was totaled on one of it's first flights after I put it in a spin and could not get it out.

buzzard bait

When you guys talk about getting into an unrecoverable spin, did you try down elevator? Not trying to start any argument or criticize anyone. I know how fast things can happen when you're flying. I picked up a kit off ebay and I'm just trying to be prepared, because spins are definitely something I like doing with my planes.

Looking at the plans, I can see how that swept back fin/rudder might get blanked out by the stab in a spin. I would expect diving (if you have room to do it!) might restore air flow over the rudder.

Also, compared to the full scale airplane, the fin/rudder are much more swept back on the VK. It was a common practice back then to try to reduce some of the dive you would get when applying rudder. Maybe a more scale-like fin/rudder would be less prone to the spin problem.

Just throwing out some thoughts here.

Hey Slim, you still there? Did you get 'er finished?

Jim

tailskid

My Feedback: (34)

i have one of those NIB somewhere around here....build and RE-built my first one in 1970...was my real first R/C model that flew

049flyer

My Feedback: (18)

Oh yea!!

Took it up REAL high to test the spin characterisics. She snapped right into a spin and stayed there all the way down. I had penty of time to try everything I could think of, down elevator, opposite rudder, ailerons. Nothing worked and down she came, SPLAT! Right on the runway.

Cured my addiction to "Scale" looking models with time intensive finishes.

I'll never build another because I like spins too. But if I did I might try a few things different. Larger rudder or elevator, maybe start with a well forward CG or something else to tame it down or help recover.