Anyone know the correct mounting spacing for the 50NG? I downloaded some from www.aerobaticmodels.com, but comparing them to the actual 50NG - they're off quite a bit.

Edit - found it - 72mmx50mm according to this: http://www.rcshowcase.com/html/dimensions.html

Now, where's my &^%$! metric tape measure?

Second Edit - damn, I DO have a metric tape at work. Good thing too - the pattern is closer to 72x52mm [X(]

Thanks!

Well you can always measure the engine, or the specs are on ZDZ's website if want to double check what RCS has but I wasn't aware that their website was even still up since TBM bought 'em out.

The other thing you might consider is hitting the local Harbor Freight and look for the 6 inch (they call it a 0-150mm) digital caliper. Not suggesting I'd use it for machine work, but mines been a real time saver for model stuff. Cost's about 15 bucks or so and goes from SAE to Metric with the press of a button.....

Thanks Zeeb - I am now $10 poorer - but that caliper really did the trick measuring the ears and laying out the holes. Motor went on the Ultimate last night (came back off as there's a lot to do still).

The choke arm has a huge hole in it -any quick ideas? TBM will (eventually) offer a ball link arm for it like RCS did - but it's not in stock.

Hmm....

Well that carb linkage question has been something I usually have to tinker with and none of my models are the same. I used the arm that comes swedged on the choke arm with one, another one has the one of the arms that came with the engine from RCS, one's got the swedged arm taken off and a machined extension on it to get it below the engine box, the 50 has an arm from DA on the throttle, I think you get the idea?

It doesn't have to be something from TBM for a ZDZ, don't they have any arms for Walbro carbs? How 'bout checking with DA? Maybe Don's Hobby out in Kansas as they've got LOTS of GS stuff? Just have to kind of look around if you're like me and building something from scratch is "difficult"?

Oh, glad the ten dollar investment seems to work. I only buy a few things from Harbor Freight and stumbled across that caliper one day and thought it might be useful. With all the mixture of SAE and Metric you run across in the hobby, that little puppy has been one of my better tool investments. Just another suggestion; go hit the local Walgreens or whatever for a three pack of spare batteries. The last quite awile but seem to die at inconvenient times... lol

Figured out the choke connection on Friday. Used one of those short brass servo "bushings", it was close enough to the ID of the choke arm. Picked up a 2-56/2-56 DuBro ball link, the 2-56 machine screw is a perfect fit in the bushing. A bit of locktite on the nut and cranked it down - not going anywhere. Did have to sand the ball link shorter to keep it from hitting the firewall. I'll run Goldenrod back to a 81MG (probably) to actuate the choke - still looking for a way to do that manually if possible - may try a bellcrank and turn it 90 degrees out.

I did this on two 50NG's. It's not that hard. I think I bought a small nylon nose gear assembly. I mounted the nylon "pillow blocks" on a little 2x3" thin ply plate with 2-56 hardware. I used a piece of brass tubing as an axle between the two nylon "pillow blocks" to hold the bell crank. The axle went left to right in the motor box. I used a 2-56 ended carbon fiber pushrod that went between the top of the bell crank and the choke arm on the carb. I used a 2-56 ended (one side only) 2-56 threaded rod on the bottom of the bell crank and let it hang straight down. I just push and pulled this by hand. I used 4 servo screws to fasten the ply plate assembly where I needed it. I can post pic's to explain it easier.

Pics would be great Joe - thanks!

Sounds good. Heck I might as well just throw just throw one in an envelope and mail it to you. I don't need them anymore. I'll see if I can find them and let you know.

PS: I forgot that I had to drill a hole in the ply plate for the rod to go down through. The plate mounts on a horizontal plane....stood off the bottom of the motor box for example.

I'll sort through the pictures of the plane (GP Ultimate) here in a bit and see if there's a spot behind the firewall in the "engine box" to support the bellcrank

Jeff/LAX

Save the postage Joe - the bellcranks are only a couple bucks at the LHS (I've left a message for the wienerdog to run across the street to Hobby People and pick some up)

Looking at what you wrote, and some of the pictures I've slurped off the GP Ultimate 160 build thread, here's my plan:

Mount a piece of 1/16" ply "fore to aft" between the firewall and the fuselage former that will allow me to mount the bellcrank vertical. The forward part of the 90 degree bellcrank will be vertical, I'll run typical dubro 2/56 ball links and 4-40 rod from the choke to the bellcrank (2-56 ball, 4-40 bolt). The other part of the 90 degree bellcrank goes aft, I'll put another ball link on it and "drop" a 4-40 rod straight down to between the landing gear mounts (adjacent to my fuel tank vent. This should allow me to reach under the plane and push up or pull down to work the choke.

It all makes sense on the sketches on my white board. One of these days I'll actually sketch something airport related on my white board, and my staff will have me committed!

That'll work !!!

The nice thing about manual chokes is that your bell crank/linkage can be a little sloppy and it doesn't matter (just as long as it stays on).

My other gassers have either been easy enough to reach into the cowl, or lended themselves to pulling from the front.

Here they are. Let me know if you need anything else.

Between you and Keary (from the Ultimate thread), I solved it. Ran a support front to back in the engine box, took a 90 degree bellcrank and transferred the motion down.

That looks great. Nice work.

Forgot to thank Joe too - if enough of you poke my brain cells, eventually something floats up!

Glad to help.