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motor mount?

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Posted

Will a motor mount and ea 81 work on a mk4 from a kitfox 4?

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Posted (edited)

Will a motor mount and ea 81 work on a mk4 from a kitfox 4?

YES, BUT you will have to either modify the mount or put some bushings on your firewall to match the mount.  Going to be nose heavy - I extended the leading edges on my wings about 4" and enlarged the tail - moved battery to tail.  EDMO

Edited by EDMO

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Posted

Why all the work instead of running the 582 ? All the added weight and not much in performance gain that I know of .

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Posted

you will have to make some serious mods to the mount.  Firewall mount locations are way different on a KF versus Avids.

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Posted

Leni is right, Kitfox has 5 mount points. (from top of firewall down)   2 on top, 2 in the middle, and 1 at the bottom.  Avid has 6, 2 at the top, and 4 across the middle of the firewall.   Also, if I remember right, the bottom mount on the Kitfox is 1/4" further out or in then the others.  Also, unless you have the streached Avid fuselage, you will have serious issues with the heavy weight of the Subaru out front where a much lighter engine was originally figured to be.  Then you will have to put a bunch of weight in the tail to get the W&B to work out.  It will end up being a two place aircraft if one is a small kid... :-)  And it you did use a Subaru on the Avid, I believe you are supposed to put an additional mounting point down at the bottom of the fire wall for the motor mount.  Don't you have a nice light 582 for that plane?  If you really want the Subaru engine, I have one I will sell you with an NSI gearbox on it.  Even has a Kitfox 4 mount bolted to it.... JImChuk

PS  sorry if I got carried away with my answer.  The internet was down all day, and I'm just getting back on line............

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Posted

Don't really want a heavy soob, one popped up locale, so I was interested. I will be flying over a lot of water, so would like the reliability of a four stroke. I really want to do the rx-1 conversion. Seams like weight and balance would not be to difficult. Need to sell my fwf..

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Posted

A 582 is a proven reliable motor and I fly over water and swamps all the time . A 4 stroke can go bad just as fast as any motor if it's not maintained. I'd just stick with the 582 . The yamaha is nice but I prefer having dual ignition just in case something goes wrong . 

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Posted

If you go with the 582 get rid of oil pump and mix the gas.  I had a pump that was bad.

 

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Posted

In my opinion that should be done with any 2 stroke injected motor . One less thing to fail on you . 

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Posted

Someone may want to check my math but my 582 powered 25 year old fox has over 1300hrs on the clock. 45 knts would be a realistic average speed over the aircrafts life. that's around 58000 nautical miles,nearly 3 times around the world without an oil injection failure(or any other failure other than loosing one ignition)these engines if cared for are very reliable.

I'm sure over that time someone would have forgotten to add oil to the mix:wacko:

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Posted (edited)

A 582 is a proven reliable motor and I fly over water and swamps all the time . A 4 stroke can go bad just as fast as any motor if it's not maintained. I'd just stick with the 582 . The yamaha is nice but I prefer having dual ignition just in case something goes wrong . 

Yep, true.  In any particular case there are still plenty of ways for a 4stroke to give out.  

But I'll be in the 4stroke camp now with 5 2stroke failures in the last 10 years. (4 snowmo, 1 aircraft).  I'll own 2 of the failures myself (pushing too hard on a high time motor), but I'm very sure that I would have had zero failures had each of those motors been 4strokes subjected the same duty.

And dont forget the yamaha has 4 independent coils/CDIs (one on each cyl).  If one were to fail, you'd still have approx 80HP available.

 

Edited by MN Kitfox 2

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Posted

Found a rx-1 for 2200 in my area, Maybe look at it next week.

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Posted

I think you are not in the real picture here. If one of the coils on an RX1 engine fails will the engine run on 3 cylinders?  If so, I highly doubt there will be 80 hp there.  

Same with the Apex 3 cylinder engine. Will it run on 2 of 3?  I seriously doubt it. 

This is my main hang up with these engines.  To each their own, but I won't fly a spark ignition engine without a redundant spark plug in each cylinder. 

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Posted

Yep, it'll run.  But you are probably right that my 80 hp guess is a little high.  I'll say 70 or 75 hp for sure though.

Here's my math:  In the snowmo forums I've guys chatted with guys that have had a coil go bad on the 3cyl rotax 1200 4tec (known problem with the connecting clip atop the coil).  With one failed, they have run home on 2/3.  They say max speed is about 65.  From all the little sleds I've owned, IMO that take around 60 hp on a 500 lb sled with a 200 lb rider.  So that is with 66% of cylinders working and about 46% of the 130hp the engine normally pumps out.

So on the  4 cyl then with %75 of cylinders working, straight interpolation puts you at 72.45 hp, but (again IMO) I think some effeciency would be gained from 2/3 to 3/4.

When I get her running I'll pull a coil connector for ya and video a little run up for ya.

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Posted

 To each their own, but I won't fly a spark ignition engine without a redundant spark plug in each cylinder. 

Same goes for me with auto conversions.

Have fun, good luck and be safe.

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Posted

 To each their own, but I won't fly a spark ignition engine without a redundant spark plug in each cylinder. 

Same goes for me with auto conversions.

Have fun, good luck and be safe.

Can't argue with ya at all on your decision for DI as a personal requirement.  It is better to have that redundancy.

But I am glad that you brought the question here because the rx1 engine choice is not one I took lightly.  You challenge one of the main premises I had made about that motor (that it would run well enough on 3 cyl to eek out a meager climb in my KF5 on lotus floats).

But first my apology to Jared here for hikacking his thread!

Give me a second to type and then lets hop over to my thread and I'll lay out my plan to test my premise:

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Posted

Hey Jared, I have some measurements for you over in a personal message I sent.  Find your message up in the user panel at the upper right of the page here.

That way we can communicate without cluttering up the forum.

Brett

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