Aviation Models 35% Yak with 3W 106

[HighRoller]

Does anyone out there have this setup because I'd like some help with mounting the engine. Anyone who has mounted one of these I need the correct firewall measurements. Thanks and God Bless

[DarcyWingo]

Hey man, good talking to you guys yesterday...

this is an easy way...plus you can get it dead nuts on, without measuring

[HighRoller]

Hey brother, I appreciate the wealth of info you gave my Pop. But exactly what am I looking at in the photo? You got me! LOL!

[john330l]

The plane is standing straight up in the air so the motor can be moved around until centered on the firewall. Holes can be marked and away you go!

[HighRoller]

So do I just center the engine on the firewall or do I need some sort of offset? According to the manual (which is attached below) the engine mounts to the lower right of the firewall? Still confused. Please Help. Thanks

[Leardriver]

Just use the indications in the manual and you will be about perfect. There is approx 2 deg offset built into the firewall if you build the box as spec'd. You can check out my build thread here at http://www.rcuniverse.com/forum/m_3624981/tm.htm.

Once you have the firewall in place, measure down from the top 2 3/4" and draw a horizontal line. this represents the "center" of the engine vertically. Now measure 3 1/2" from left or right edge of the firewall and draw a vertical line (top to bottom)...where the two lines intersect is where the "center of the cowl opening would be...BUT...we have a few degrees of offset built in so we need to "shift: the engine a little to the right (while facing the engine) so measure over an additional 1/4" and now you can easily figure out where to drill for the mounts by using these reference lines. Simply measure the distance between the mounting plate holes and divide in half! Simple.

If you have any addition questions feel free to email me as I am working on the plane as we speak.

Good luck,
PaulP

[HighRoller]

Gotcha Paul. I'm waiting on a reply from Cactus to find out what to do about the headers. If I mount the engine according to those measurements my headers are dropped quite low. Also I have the intake manifold so I'll probably have to cut out the cowl for it to fit. Thanks everybody!!!

[Leardriver]

You have to cut out the bottom of the cowl anyway, but there is a ton of room below the carb! I think it will be fine...although you may have to look at the throttle pushrod. I'm not sure how much interference there will be with the that intake manifold that #W (hehehe) uses. Also, I am using 50mm drop "flex" headers on mine and they are gonna work out well. Here is a pic.....
PaulP

[torquen]

Its best to use the exact dimensions off the manual on the site. I just mounted a 106 on my friends 35% yak and we used these exact dimensions and it came out perfect. The ladder method works ok, but you are not getting an exact position. You are getting what looks the best by eye. Put you fire wall all the way back to the bottom of engine box once you have drilled your mounting holes. Then glue your fire wall to the box and use 1/2" spacers behind the engine to allow just a little air to flow behind the cyl. This will give you perfect location and clearance.
Garrett

[HighRoller]

Hey Garrett, Bobby from Cactus is supposed to be calling you about the headers I have for this engine. If I mount the engine per the manual these headers are dropped super low. Bobby Says you'll know what I need to do. P.S. I've attached pics for you to see. Thanks MIKE

[Cajun]

Ouch that's off by a good bit, Can you get them rebent at a sharper angle? Or maybe you can get some customs ones made.

[Leardriver]

Those headers have way too much drop. You need headers that have much less than that. Send those back and get some lower drops...flex headers help also. MOunt the engine per the manual...not around the headers that you have!

PaulP