Ring mount for 912/914 on Model IV

[Freedom2]

Does anyone know of a ring mounted install 912/914 onto a model IV??

[Av8r3400]

It's a project I've wanted to do on the Mangy. It was part of my original build plan.

It will push the engine forward at least 3-4". This can be a problem for many model IVs which are already nose heavy...

[avidflyer]

On my never finished Kitfox 4, when I was looking for a 912 motor mount, a guy had a Kitfox 5 mount with the ring mount. He got the mount remodeled to fit a Kitfox 4 firewall, so I have a Kitfox 4 with a ring mount, but it didn't start out that way. The engine does sit probably 4" further forward of the regular Kitfox 4 912 mount. We did add the two inner tubes at the top of the mount for more support. JImChuk

[Freedom2]

It's a project I've wanted to do on the Mangy. It was part of my original build plan.

It will push the engine forward at least 3-4". This can be a problem for many model IVs which are already nose heavy...


This is not so much of a problem as you may think, I have a buddy not far from me that has a model IV with the 914 on his. He put his battery below his horizontal stab and also put the bigger elevator on his so i know 1st hand this is can be done. I'm just going to start a model Iv build and would like to do the edge-performance 912 or 914 but of course i need a ring mount. Probably will have to make one up myself judging by the replies on the forum that there is know info out there on the ring mount.

[Freedom2]

On my never finished Kitfox 4, when I was looking for a 912 motor mount, a guy had a Kitfox 5 mount with the ring mount. He got the mount remodeled to fit a Kitfox 4 firewall, so I have a Kitfox 4 with a ring mount, but it didn't start out that way. The engine does sit probably 4" further forward of the regular Kitfox 4 912 mount. We did add the two inner tubes at the top of the mount for more support. JImChuk


I just saw your photos after i sent my 1st reply to you. Do you know how much of an effort it was to remodel the 5 engine mount? Seems like a easier procedure than starting from scratch. I'm assuming you are going to use that mount? Are you putting the 912UL in your kitfox?

[avidflyer]

It's been quite a long time ago, but I believe that the center two mounting holes are closer together on the earlier model Kitfoxes then the 5 and later. Maybe someone can measure their model 5 or newer fuselage and provide the bolt pattern for the motor mount. I can do the same for my model 4. When I finished my other Kitfox 4 with 912 a few months ago, I had the 12 lb battery mounted about 2' behind the seat. When I did the weight and balance calculations, I ended up moving it forward to just behind the seat, cause I was starting to exceed the rear of the CG envelope with any weight in the baggage area and at full gross weight. So having the engine 4" forward may not cause to big of a problem CG wise. I do plan on finishing the Kitfox eventually, so I suppose I'll keep the ring mount on it. JImChuk

[Freedom2]

JimChuk,
I thought I'd ask as I have nothing to loose, with my question with the engine you are going with on your kitfox with the ring mount. If you plan on going with the 912UL then why not go with the standard kitfox IV motor mount? If you are then is there anyway I could persuade you to sell me yours at a premium price?? Robin

[Av8r3400]

JimChuk,
I thought I'd ask as I have nothing to loose, with my question with the engine you are going with on your kitfox with the ring mount. If you plan on going with the 912UL then why not go with the standard kitfox IV motor mount? If you are then is there anyway I could persuade you to sell me yours at a premium price?? Robin

The main reason to go to the "proper" Rotax ring mount over the OEM mount is to have the carbs oriented properly and have the oil tank at a more correct position relative to the engine case. Additional benefits include the ability to use the Rotax tuned intake plenum or install a 914 or other modern engine.

Kitfox was one of the first kit manufacturers to offer a 912 engine package and way back then (late 80s) there was little support from Rotax as to mounts and requirements. Kitfox designed their own mount system with the information that was available. It is a decent mount, but far from optimum.

[Freedom2]

Ok thx for all your info and pics. Every little bit helps. Well at least I now know there are two ring mounts on a model IV out there. I'll keep doing my homework and get this ring mount figured out.
Robin

[Freedom2]

On my never finished Kitfox 4, when I was looking for a 912 motor mount, a guy had a Kitfox 5 mount with the ring mount. He got the mount remodeled to fit a Kitfox 4 firewall, so I have a Kitfox 4 with a ring mount, but it didn't start out that way. The engine does sit probably 4" further forward of the regular Kitfox 4 912 mount. We did add the two inner tubes at the top of the mount for more support. JImChuk

Hi Jimchuk, just wondering if you wouldn't mind taking a measurement from your firewall to the prop flange on your 912 with this ring mount? would help me out alot

thx. Freedom2

[avidflyer]

I don't have the engine mounted on that plane/motor mount any longer, but I believe the measurement you want is 29 1/2". Thats about 4" longer then the standard Kitfox 4 factory mount would make it. I may have a picture somewhere. I'll look. JImChuk

[Freedom2]

thank you!!