Engine Mounting in 37.5% TOC YAK

[falconpilot]

Anyone that has built one of these, I need your help here. The direction suggest that when mounting the engine, you should offset the engine on the firewall in order to center the cowling. I've always mounted the engine on the centerline to avoid any "weird trim" conditions. For those that have built this airplane and flown it, how did you do it??? Thanks Jim

[3Dguy]

The offset may be to compensate for right thrust built into the motor box... and to center the engine in teh cowling. lol

[rdgood]

When I mounted my DA-150 I stood the Fuse upright and carefully tied to a ladder. I then centered the motor in the cowl ring - marked the holes carefully with a sharpy. Prior to mounting I also marked a center line from the leading edge of the wing cutout on the side of the fuse to be sure my vert height was on the thrust line. The left and right centering will de determined by the cowling. I really like setting up my engine alignments this way. The old trig method method sucks but does work but is painful and tedious.

Thanks,
Ronster

[freya1]

find center on the firewall then go 1/4 inch to the right when lookin from the front of the airplane, the sides of the motor box are different lenghts for engine thrust.

[3Dguy]

	Quote: Originally Posted by rdgood
	When I mounted my DA-150 I stood the Fuse upright and carefully tied to a ladder. I then centered the motor in the cowl ring - marked the holes carefully with a sharpy. Prior to mounting I also marked a center line from the leading edge of the wing cutout on the side of the fuse to be sure my vert height was on the thrust line. The left and right centering will de determined by the cowling. I really like setting up my engine alignments this way. The old trig method method sucks but does work but is painful and tedious. Thanks, Ronster

Something about strapping a 40% upright to a rickedy ladder just makes me nervous.

[rdgood]

3Dguy,
Its a very common practice for giant scale folks to accurately find the engines true center. I am not the only one doing this procedure..

There a couple of other more tedious ways to skin this cat. I find the vert method the least tedious and most accurate. Just gotta be careful and have a flying bud help you carefully secure everything while you position the motor and find your holes. I have found that the two planes I did 37.5% yak and a Comp Arf G202. That the gear would straddle the ladder rather nicely with a piece of sponge foam wrapped around legs worked perfectly. Tail cleared the floor by a good 2 inches. Oh dont use a rickety ladder be sure to use a nice one! This method does work~~ quite well actually. I got the idea from Mickey Crawley a flying bud in San Fran Ca area.. Great guy by the way. I think Darcy Wingo has pictures of His 37.5% yak on a ladder when he did his centering of a DA-150...on this website someplace...

Hope this helps!

Ronster

Of course if your model has nice template well than....

[3Dguy]

Yea, I know everybody does it... I guess that means everybody's crazy!

[rdgood]

Suite yourself!!!


Ronster

[3Dguy]

[3Dguy]

Alright, I'll jump on the bandwagon.

[cloudshaker]

I'd use one of these templates.

[Curtis_Lloyd]

I realize this is an old thread but I have recently heard about using a ladder to mount the engines to the fuse. Can someone explain the priciples involved with this method? Is it simply that the engine mounts rest on the (now) horizontal firewall for a more simple "hands-off" way of marking the alignment holes on the firewall?

[enephel]

You set the engine on the firewall and put the cowl on over it. Move the engine around until you have it centered in the cowl opening and then mark where the holes will need to be drilled. This does get it right the first time.