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Kitfox IV 912 exhaust

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Posted

I am looking for photos of Kitfox IV 912 exhaust. I think that may be what the builder installed in my Fat Avid. I am hoping so anyway. Looking at some photos might help me determine if my exhaust is indeed from a KFIV. 

My exhaust is getting pretty long in the tooth. It would be awesome if I can just buy a complete exhaust that fits instead of building up something custom.

Thanks!

Chris Bolkan

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Posted

I am looking for photos of Kitfox IV 912 exhaust. I think that may be what the builder installed in my Fat Avid. I am hoping so anyway. Looking at some photos might help me determine if my exhaust is indeed from a KFIV. 

My exhaust is getting pretty long in the tooth. It would be awesome if I can just buy a complete exhaust that fits instead of building up something custom.

Thanks!

Chris Bolkan

Chris,

I will be fabricating the exhaust for Randy Tylers fat avid this weekend.  I will take pics of what we build.  

:BC:

 

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Posted

Awesome! Appreciate that.

Does anyone have photos of stock KF IV 912 exhaust they can post?

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Posted

Sorry Chris, I have one, but it's all packed away and I can't get to it for a while.  I looked, but the pics I have don't show it well.  JImChuk

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Posted

Awesome! Appreciate that.

Does anyone have photos of stock KF IV 912 exhaust they can post?

in the box. 

FE5C07AE-2F2C-4AB7-ACE8-EE28DE1B908C.thu

In its normal state (broken):

 

15CB5BE2-9008-4F0C-8A01-245185196834.thu

 

 

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Posted

The one in the box looks exactly like what is on my plane except mine is missing the tailpipe safety clamp. Mine has cracked in a few places which a friend has welded up but I think it is on its last legs. However it was flown for over 300 hours before I got the plane.

Is that exhaust still available from KF or some other supplier?

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Posted

Yes, you can still get an exhaust through Kitfox for a model IV.  There are a couple variations, though.  They deal with the angle of the stinger exit. 

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Posted

Good to know about stinger variants. Thanks!

I saw a newer KF exhaust and it is a far better design in that the front and rear header pipes are offset symmetricaly on both sides where they enter the muffler. That would provide far better triangulation than having the offset on only one side like mine. But mine is what it is. I’m just happy that the photo you posted looks like what I have and is still available and I may not have to do custom.

Thanks Larry!

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Posted

I have that system shown in the box, installed on my plane now.  I hope it lasts.  My next step will be to replace the slip/sleeve joints on the muffler with proper ball and socket joints to allow for some movement.  I believe this is the major problem area.  It is where my first plane cracked (as well as around the stinger) and where my last system on the plane cracked prior to the stinger failure.  If you look at the cracked muffler you can see the major reinforcement pieces around the slip joints.  This misaligned the sleeves enough that assembling the system went from a real pain to almost impossible.

IMO, this exhaust system is a poor design from Kitfox with many area that could be improved.

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Posted

I agree about poor design. The KF7 exhaust looks better. It is triangulated better as both front pipes angle in towards the middle of the muffler while the rear pipes basically go straight down to the outsides of the muffler. This makes two triangles to oppose side to side shaking and the associated flex which is what breaks everything. Unfortunately, my exhaust really only creates a triangle on the passenger side. The front and rear pipes on the pilot side both go down to close to the same place on the muffler which makes only one triangle to oppose the side to side shaking. It would take a major re design to incorporate the KF7 style so I am stuck with KF4 style or some variation of it.

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Posted

If the 7SS system had proper ball joints, I'd buy one today and modify my FWF to make it fit.  That design is prone to breaks as well.  I am convinced it's the sleeve joints.

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Posted

Here are some installed.

IMG_1096.JPG

IMG_1097.JPG

IMG_1098.JPG

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Posted

Paul - Is that Dallas' plane?

 

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Posted

Paul - Is that Dallas' plane?

 

yes it is.

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Posted

Interesting solution to keeping the heat off the lower engine mounts.Those mounts do burn:bugeyes:

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Posted

Chris,  Here are the pictures of the exhaust we built at Leni's for my 912 install.  Leni was not too happy with the performance of the tubing bender since it did cause some wrinkling of the pipe at the bends.  Since it is a mandrel bender it really should not do that, but it still came out pretty good in my opinion, much better than a lot of slices and welds to make the bends.

DSCN3211-1.jpg

DSCN3212-1.jpg

DSCN3213-1.jpg

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Posted (edited)

Very nice looking setup, Randy.  (...and Leni!)

Is that a Rotax muffler-can or custom as well?

Edited by Av8r3400

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Posted

Looks good Randy. 

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Posted

It's the factory Rotax muffler kit but it might be a newer model than the one you have.  The muffler has ball and socket connections for the pipes to the muffler.  The kit has all the socket ends, the pipe ends that fit into the head, 4 180 degree elbow fittings, all the pipes and all the springs and spring tabs.  It just takes a talented bender and welder to complete.

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Posted

It's the factory Rotax muffler kit but it might be a newer model than the one you have.  The muffler has ball and socket connections for the pipes to the muffler.  The kit has all the socket ends, the pipe ends that fit into the head, 4 180 degree elbow fittings, all the pipes and all the springs and spring tabs.  It just takes a talented bender and welder to complete.

My exhaust is a Kitfox factory system.  It doesn't use ball and socket joints, that is the major flaw in it's design in my opinion.

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Posted

That's my friend Jeromie.

He was building a carbon fiber plane. It consisted of a carbon fiber fuselage. Murphy Rebel wings I think, aTitan tornado full flying empanage and a kitfox7 firewall forward. He got a lot of the way done but abandon the project and ended up just buying a clipped wing piper. So he is parting everything out. 

He has the complete KF7 FWF setup minus engine. This exhaust is part of that setup. i was hoping I could use it on my Fat Avid, but it won't work.

Anyway he now has a lot of random stuff for sale and what doesn't sell will be thrown away.

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