reyn3545

I iknow this model from CA is several years old, but I just ordered one this weekend. I was wondering if any other builders may have used the 3W 75i and still have some pictures of the engine mounting to share? It looks like a Pitts is probably the only exhaust choice, but I want to make sure I get the engine on right.

bubbagates

My Feedback: (32)

I seem to remember I used 1.5 inch standoffs on mine with a 3W70iUS. You can go to Lowes or Home depot in the isle where the bolt trays are and get thick nylon standoffs in 1/4 inch increments. They are drilleed perfectly for 10/32 bolts.

Also take into accout the motordome has no right thrust or up thrust built into it. Here is what I did to get mine lined up.

I set the tail on the ground (be absolutely sure you protect the rudder phelnonic horn in the vertical stab) and install the motordome. Now set the engine on the motordome with the proper length of standoffs. Slip the cowl over the engine (you will have to do a rough cut to get the cowl over the head) and get the cowl lined up and tape it in place. Now move the engine around until you get it centered then move to the pilots side 1/8 inch for right thrust. Gently remove the cowl, trace around the standoffs and remove the engine, drill the holes in the center of the tracings you made.

Now wehn you mount the engine use 3 washers on both pilot side bolts and which will give you 3 degrees of right thrust and then it will line up in the cneter of the cowl.

the reason I say 3 degrees is I am assuming you are going to start out with a 24x10 prop. You will need 3 degrees to get perfectly straight uplines

It sounds like a lot but if done methodically, you can have it all done in about an hour, give or take 15 minutes

reyn3545

Thanks! My 3W is not the US model, and I;m wondering if I'd have to butcher the motor dome to get the carb through it... may be its e-bay time for it!

Flyjets

My Feedback: (51)

Bill

After building 6 CARF Yaks and Extras of all sizes I have to agree on how to properly mate up the Engine to the Firewall.

On the Giant 3M + units I have to stand on a ladder to adjust the motor and line it up.

reyn3545 just center the motor in the cowl as discussed.

Ian

bubbagates

My Feedback: (32)

I would think some type of cutting is needed since it's the rear carb version, sorry I did not pick up on that one sooner. I'll be pulling my cowl later today to check things over and if you would like I can get you the length you need from motordome to spinner backplate

Flyjets, that's a trick WH has you do to their planes and it works well. I'm in the middle of doing my 4th C-ARF and it just works, forget the measurements in the manuals/ It's heck when you need a ladder because the dang thing is taller than you

didiwatt

My Feedback: (38)

reyn3545
the white one has an ZDZ80 in it, the middle 2.3 has a BMI 105 twin, and the yellow one has a rear exhaust 3-W 75. I used a can for exhaust and yes, you have cut up the motor dome on the 3W 75 as well as the ZDZ. I used aluminum stand-offs on the 3W and installation was not that hard other than mounting the throttle and choke servo in the rear of the motor dome. Power was excellent. However, my 3W had an enormous amount of vibration that I was unable to get rid of. It was so bad I feared for the integrety of the plane over the long run so I swithced to a ZDZ80 which is considerably smoother. Can't speak for all 3W75's but mine was a shaker.

As far as right/down thrust, I think that in only one of th 2.3's I added a little right thrust.

They are great flying planes but you do have to get used to the "CA Balooning" on landing.

Paul

didiwatt

My Feedback: (38)

Oooops, here is the picture

reyn3545

Thanks for the replies... this is my first CA, so I wanted to check with the experts!