? M-IV-1200 smooth cowl w/ROTAX 912 ?

[GWright6970]

BACKGROUND
I received my firewall forward kit from John and Debra last week; and I am reading ahead on the installation. These questions are regarding the fabrication of the firewall.

There are two (2) differences between my original construction manual with the round cowl, and the new instruction chapter (for the Lite Squared) for the smooth cowl.

In these new instructions, for the smooth cowl it appears that I install an "inset box" in the firewall to receive the oil reservoir which is set into the firewall, rather than in front of it in the round cowl installation.

In the new instructions, there is NO mention of installing the "firewall starter shroud," P/N 42704, which is that small piece of stainless sheet metal that is installed in the co-pilot foot well, to allow clearance of the starter motor.

QUESTIONS:
1) I am creating this post for this question: Is the smooth cowl motor mount of such size, that it places the engine further away from the firewall, such that the small inset "firewall starter shroud," P/N 42704, is NOT required for the Rotax 912 installation?

2) Am I correct in assuming that the oil cooler inset must be installed for clearance reasons? (It seems to me that it must, as there must be some clearance issue that does not occur with the round cowl. If the answer to the question #1 above is that the engine is moved forward, why is the oil cooler needed to be further back into the firewall as compared to the round cowl?)

For those of you who have gone before me, please let me know if I need to install the oil cooler inset, and do NOT need to be concerned about the starter motor inset.

THANK YOU!!

[mr bill]

If you are using the standard starter, you won't need the notch in the footwell of the firewall. With the oil cooler mount from Kitfox, removing a little from the inside lip of the cowl is all that is required. Fitting the oil tank into the firewall was a bit of a pain, I wound up shortening the tank 1/2 inch or so. Dawley Aviation did the rewelding on that. All in all, not difficult, but it will take time.

[GWright6970]

I think I have the standard starter! The engine was manufactured a couple years ago....

Your response and pictures are great!!! I now also have a better idea about those arms that attach to the engne. I guess it gets better when you are actually doing the work, as opposed to reading it and "envisioning it all!"

THANK YOU!

[GWright6970]

I am going to continue this thread and use it to document my experiences with the smooth cowl on a Model IV-1200 with a ROTAX 912UL installation. I hope that others who have, or are considering, feel free to add and comment.

It is NOT a straight forward installation. I had problems with the top cowl which are documented in another thread. That solved, I am now trying to get the oil tank installed.

After installing the firewall, and re-installing the engine mount and engine, the instructions say to slip it into the box inserted in the firewall... but like Bill (mr. Bill) stated above and shows with an excellent photograph, it does NOT happen that way. Maybe with a sledge hammer, but certainly not with anything less!

My opening is actually slightly greater in height than called for, as I tried to not have to cut the tank! I am at 9 5/8" when the opening is called for to be 9 1/2". It be any taller, as the cross tubes above and below limit that height.

I removed the engine mount and engine again, attached the oil tank losely in the mounts and the engine mount, and tried to install that as a unit. No way... a failed idea. Can't get the engine mount close to the firewall... the oil tank stops it short.

So I toss it out to the forum, before I go off and try and find some firm to cut about 1/2 inch out of the oil tank and weld it back together, has anyone actually installed one in the Model IV-1200 smooth cowl WITHOUT the cutting and welding of the oil tank? If you did, HOW??!!!

I hope that this is the last serious challenge in this install! I want to go fly it!! Cheers!

[GWright6970]

Back in the hanger!

If you remove the engine, you can set the oil tank in the inset... then bring up the engine mount and engine... I am using AN4-27 bolts (longer than the -25s that will be used in the final installation) so that you can snug up the engine mount to the bulkhead. Please note at Point #1 in the photograph that the oil tank has contacted the rear cover plate of the engine. There is still 1/2" or more to go at Point #2 on the bolts to bring the firewall into place and get torqued up.

Bill cut his tank to resolve this issue.

My question at this point is: Can I remove just enough of the plastic on the top of the cover, to allow the tank to get closer to the engine?

I searched this forum and found this thread:

912 rear cover
http://www.teamkitfox.com/Forums/sho...912+rear+cover

Evidently this cover is an option?

For those that did NOT cut their tank, and this all worked, do you have this rear cover?

I am thinking that its possible, that the original installation and basis for this smooth cowl design, was based on an engine that did NOT have this cover....

[mr bill]

I would not remove the plastic cover, as it keeps things (wires and hoses especially) out of the alternator. It also keeps the flywheel from cutting those things. If done carefully, dinging in the oil tank where it is closest to the alternator is an option. It won't take much, but go slowly and take care not to cause cracks. Definitely not for the faint of heart. My tank wall thickness measured .012, so welding should be done by someone with lots of experience. I used Dawley Aviation (they manufacture and repair stainless steel exhaust systems) in Burlington, Wi.

[GWright6970]

Bill... PM sent to you!

I am sending my oil tank to Dawley tomorrow!

[Av8r3400]

I don't have the plastic cover on mine and I know of many, many more that don't as well. It's a cosmetic thing that means nothing.

If your wiring and plumbing is properly secured, there is no conflict going to happen with the flywheel.

I'd personally be more leery of modifying the tank unnecessarily than discarding a cosmetic cover.

[mr bill]

I don't think Rotax put the cover there as a decoration, besides I am a belt and suspenders type when it comes to airplanes.

[Steves142]

I mounted my oil tank at an angle and it works fine. There was no way the cooler was going to fit in front of the engine where it was supposed to so I mounted it under the engine. So far, flying in 70 degrees F = 196 oil temp.

I'll post some pictures tomorrow.