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Avid Model C or Mark IV

23 posts in this topic

Posted

Hi All,

I purchase a rotax 912 ULS and want to get a motor mount.  My question is if the Model C and Mark 4 have the same bolt pattern for the motor mount.  I am hoping to find someone who currently has a 912 on their AVID and maybe they have a design or someone with a  jig that can make a mount for me.

Thanks

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Posted

B, C, and MK IV should all be the same mount.  JImChuk

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Posted

Okay I talked with Kitfox and they said that they think their kitfox 4 912 mount will work on an avid flyer.  What do you think?

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Posted

I don't believe the Kitfox mount will work on an Avid.  The attachment points on the firewall are different.  When I'm in the hangar later, I'll try to remember to snap pics of the Avid and Kitfox firewalls.  JImChukj

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Posted

Interesting.  Kitfox was pretty sure they are the same.  That would be great if you could check.  I know that Brett makes them but I don't want to wait two years to get it.

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Posted (edited)

Got the pics faster than I was figuring.  Two pics are a Kitfox 4 Subaru mount.  5 attachment points, with one of them way at the bottom.  Other pic is my Jabiru mount bolted to my Avid MK IV.  6 attachment points,  bottom 4 all in a row.   JImChuk

Photo0845.jpg

Photo0848.jpg

Photo0846.jpg

Edited by 1avidflyer

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Posted

That is way different.  Thanks for the fast response.  Brett will probably never answer his phone so I got to figure out another plan.  Leni is working with me locally as well.  Would be wonderful if someone had a mount already made and ready for sell other than brett. 

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Posted

Maybe someone who has a 912 in their Avid could get you some dimentions and pictures and you could get your own built.   Mainly distance from firewall, and height of engine in relation to the firewall for starters.  JImChuk

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Posted (edited)

Okay do you know of anyone with and AVID that has 912?  Leni will make one but needs pictures.

 

Thanks

Edited by lv2plyguitar

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Posted

KF and Avid firewall attach stations definitely different. However, if you can source a KF4 912 mount cheap, it might be a bit of a time saver vs. fabricating the entire mount. Once you have the prop plate location mapped, cut and modify the legs to meet the Avid firewall bushing locations.

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Posted

For the record, the Avid 912 mounts, from Brett or otherwise, (from my experience) don't fit worth a damn anyway and will require modifications and probably welding. 

If it were me, I'd start with a Rotax ring mount and build an adapter to the fuselage. 

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Posted

Here is the picture of the rotax 912 ring.  Does anyone on this forum see any reason this ring would not work in an avid?

Ring%20Mount%20resize.jpg

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Posted

If it was me, I would post a new message entitled Anyone with a 912 in their Avid?  I'm sure there are some people on the list with 912s, and maybe have not followed this thread.  His name escapes me at the moment, but isn't there a guy in Wyoming with a 912 in his Avid.  He flew the guy back to Wisconsin to pick up Larry's Kitfox 4 in his Vari-eze.    ????  JImChuk

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Posted

WyPaul is his name.

Love the look of the ring mount.   I almost did this with the Mangy.

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Posted

I still think adapting a KF3/4 mount makes sense. The Rotax ring is expensive as hell new, way more than a brand new complete mount from Kitfox Aircraft (and waaay more than a used/surplus one if you find one), and then you have to custom build the balance of the mount anyhow. In both instances you will need to accommodate for oil tank and accessory clearance. If I already had the engine to use in a mock up, I would probably just go ahead and fabricate my own mount with help from my A&P IA (or maybe I have that backwards!). In any event, there is a good EAA Homebuilders video on how to build an engine mount.

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Posted

With the Ring mount everything fits as Rotax intended.  So much easer to deal with than the Kitfox or Avid mount.

 

I still toy with redoing the FWF on the Mangy...

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Posted (edited)

Just saw this picture on the 'other' (teamKitfox) site.  Kitfoxes having the lower mount hole on the firewall helps the bracing for this bed mount though.  Actually Avid added a lower mounting hole for Subaru installations, so you could do that as well.  Just another idea.  I actually have a bed mount for a Rans S-12, it could be adapted perhaps.  It would cost way less than that ring mount.  JImChuk

bed mount.jpg

Edited by 1avidflyer

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Posted

With the Ring mount everything fits as Rotax intended.  So much easer to deal with than the Kitfox or Avid mount.

 

I still toy with redoing the FWF on the Mangy...

Ummm, I'm thinking the Kitfox mount bolts right to the 912 as intended too. :rolleyes:

Obviously, both would require either modification (in the case of the KF mount) or outright fabrication (in the case of the Ring mount) to attach to the firewall. Plus with the KF mount, you already have a reasonably accurate start to determine thrust line and can reuse the attach bushings (rather than fabricate new) which I believe are the same. Also, as Jim noted, you don't have to use only the existing '2 over 4' Avid engine mount bushing pattern. Using the top 2 along with the outer most 2 of the lower 4 and a new center low location makes perfect sense to me, particularly if you are inclined to add a nose gear weldment to the engine mount for convertiblity. Then again, utilizing one of the existing inside lower locations might provide better options for the oil tank FWF on an Avid. Seems to me like that all adds up to less work but, hey, YMMV. Either way it's still going to take a bunch of work which is why I said I would just build my own. In fact, I fully intend to build a replica of the 912 engine mount in my Aerotrek for use on my Avid+, a design which I like better than than any other option I've looked at to date.

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Posted

Oil tank in the "wrong" place.  Carbs and intakes reversed.  Near impossible to install the four mount arms.  

Yeah, the Kitfox mount (IV) is a real peach...

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Posted

WHatever floats your boat but unless you add new firewall bushings, I don't see where the ring mount solves the oil tank location issue. Both mounts at least allow for placement of the oil tank FWF rather than behind the seat as with the Avid 912 arrangement, should one desire. I guess in a perfect world, all the tanks, carbs, intakes and stars would align perfectly. All I know is there are plenty of KF's flying in that configuration so if I can source an existing surplus KF mount to modify at $100 vs. 5x-10x as much for a ring mount that requires even more steel and fabrication, it is a consideration. Some of us have kids and college bills... yada, yada.

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Posted

Somewhere in my photo files I have photos comparing the installation of a 912 vs Jabiru 2200 on an Avid MK 4.

The 912 is really packed in there, whereas the 2200 has plenty of room.

The biggest problem is finding a place to put the big oil can, extra cooler for water and many hoses.

I'll see if I can find the photos.

LATER: Couldn't find the photo.

The advantage of the 912 is that a much longer prop can be used and if the engine is 100 HP it should climb very well. If it is the 80 HP there wouldn't be much difference from the Jabiru.

John M

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Posted

I had a model B and then a MK4 that I bought with a Rotax two-stroke.

I removed the Jab mount from the B model and installed a Jab 2200 in the MK 4 on the same mount.

Then I bought a Gen 4 2200 and sold my mount. The mount would not work on a Gen 4 since the top two mounts had to be raised 15 mm to clear the larger fins.

John M

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