ORIGINAL: Tired Old Man
Engine Mounting
Tom sent me this note the other day that applies to mounting the 3mm engine. The same information is in the manual but I thought I would post it here as well. Mounting the 3mm-53 really is this easy in the Sukhoi.
I made the mounting template and marked the firewall last night so the engine is just about ready to go on. The firewall center line is in the middle of the firewall pass through cut out so you'll need to use a couple of pieces of masking tape to mark on. Too easy. I'll post some pics of the process a bit later.
Copy of note:
I mounted the 3mm 53 on the Sukhoi today.
You will need 1" standoffs to get about 1/4" clearance between the prop
and the cowl. I just cut 4 1" pieces of 3/4" hardwood dowel and
drilled
the center. I also put a washer between the engine and the dowel to
keep it from compressing.
Make a template of the engine with the 4 mounting lugs and a small
hole where the centerline of the crank is. You can find a little bump
in the center of the rear bearing carrier, that's the centerline.
Find the center of the firewall and make a mark 1/4" to the left
(*right when looking at the front).
Mount the template to that mark through the mark to the right of
centerline. Drill your holes.
It took me about 15 minutes. I love this engine, it's so easy to work
with.
The standard muffler will fit with plenty of room.
TF
Back to mounting the engine.
I used Tom's method of having wood dowels for stand offs. Using wood has been my way from the first 28% Extra I had a few years ago and it still works great. So off to the hardware store to obtain a 48" length of 3/4" poplar wood dowel. I think it cost me a grand total of about $4.00. You can buy and use aluminum standoffs if you really feel the need but the wood ones work as well or better with no weight penalty.
Tom's plane has 1/4" clearance between the prop and the cowl, but I wanted a little more for a slightly more scale appearence. So I elected to make 1-1/4" stand offs to obtain 1/2" prop to cowl clearance. The length of the engine bolts will be determined by the lengtrh of the standoff. I had some 10-32 x 3" bolts here that worked just fine. If you elect to go shorter or longer on the prop to cowl distance be sure to consider what you can easliy obtain for mounting bolts for the local hardware store. There's always Microfastener.com or "all thread" if you can't come up with something locally.
When hanging the 3mm-53 the template method works just great. Just don't get in a big hurry like I did and miss the engine's height relationship with the firewall when you mount the engine. This one is a touch below center. Won't make any difference but the spinner may look a little funny. That's what happens when you don't follow the directions to stand the plane on it's tail to "sight" the engine and leave it laying down to make it easier.... It took about 30 minutes but I went back and raised the engine 3/16" to center it correctly. Next time I'll do it right the first time
The last picture is there as proof that I did indeed go back and fix the engine height
In any case, anyone remember where in the 3mm engine thread I noted that the carb tuning screws were in a good place? Here's the proof of that. You can't get an easier to adjust carb location. Servos for the choke (if you use a choke servo) and the throttle will be mounted on the right side of the plane. The engine box will be a good place for them when you see how the linkage runs. Tom sent me a picture of a choke servo installation so it's included here for those that go that route.
One pic here is to show the way the cowl fits the fuselage lines. Nice.