12 posts in this topic

Posted

I am the 4th owner of a 25 year old Kitfox 4-1200 project. Determined to finish! The positioning of the Jabiru cowling is giving me fits. I have Dave Jalanti's pampthlet on this installation, but I desperately need additional help with locating the lower cowl, with regard to how high from the bottom of the fuse to the top of the cowl. Any measurements and/or pics of a complete installation would be greatly appreciated.

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Posted (edited)

is your engine installed? 

Edit: is this the info you have? LINK

Edited by dholly

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Posted

The Firewall and engine are temporarily installed. That is indeed the pamphlet I was referring to.

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Posted

I still need a measurement from the bottom of the fuselage to the top of the lower cowling, at the door post. I seem to be making progress, after many fittings and trimmings to the top cowl. Checking back on the Jabiru cooling info, it seems I need much more cooling area at the aft end of the lower cowl. More than it seems I can possibly achieve! Any assistance is greatly appreciated. I really need to get this done and move on to other items.   

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Posted

I have a Jabiru on my Avid MK IV, but have no idea if your cowl is anything like mine.  I think there is a guy on Team Kitfox with a Jabiru in a Kitfox 4, although I think it was for sale a while back, so I'm not sure if he still has it or not.   JImChuk

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Posted

Thanks for the info Jim. I've seen many of your posts and I greatly respect your experience and skilled craftmanship. It means a lot to a novice. Is yours a 2200, and if so, would you happen to know the inlet and outlet areas. I am skeptical of the numbers I see in the Jabiru manual. At a 3 to one 1 ratio of outlet to inlet, a small error on the front end can result in a big difference on the back end.   

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Posted

Mine is a 2200 early solid lifter engine, # 903.  Of hand I don't know what the inlet verses outlet on my cowl is.  When I bought it from Avid 11 years ago, I mounted it on and went flying.  My temps have stayed in line for the most part.  I did make my own fiberglass cooling shrouds though.  I copied the aluminum ones Sonex uses on their planes, but made mine out of fiberglass.  Reason I did that was the Jabiru ones I got with the engine didn't want to fit under the cowl.  I'm in northern Mn, so real high summer temps are not an issue.  Maybe you don't really have a problem either, I'm tempted to say try it and fly it.  Either way, you won't know for sure till you do.  The openings on the front of my cowl are really small, I'm sure the back opening is easily 3 times (or more) bigger.  JImChuk

PS  maybe post some pictures

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Posted

Thanks again Jim. I tend to agree that it may all work out, but I am a long way from a flight test. I need to be reasonably close to the ultimate fit, so I can set it aside and remove the engine to finalize all Firewall penetrations, windscreen, brakes, etc. Still have to recover the wings and build a panel. Much to do! I also may have to fab some air ducts, since it is very tight. I admit that I am a little concerned about summer temps here in Houston. Take care.   

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Posted

Worst case, one could bite the bullet and put the rotex water cooled heads on.  Actually, except for the ADDED cost and extra weight and complexity, they would be nice on a Jabiru.  JImChuk

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Posted

From where I'm at I can't measure for sure but my outlet is at least 6 times the size of the inlet. And it does make a difference When I was building I started the Jabiru  with out the cowl Just the ram air ducts installed  and it warmed up fast. After  I installed the cowl I have never seen anything close to a hot cylinder.  When I get home I can measure for ya and try to help any way I can.

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Posted

Old school A&Ps would rivet a 1 inch strip of aluminum along the lip of the opening on the bottom cowl, if the engine was running warm. This would create more vacuum in the lower cowl area, drawing more air thru the upper cowl openings and by the fins on the jugs.

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Posted

Thanks for the responses guys. Much obliged. I re-read the Jab installation manual this morning and the area numbers were actually for the 3300. None actually quoted for the 2200. This afternoon I worked on refitting the cowlings. More trimming(4 times) and fitting and everything is coming together. I can see that it is very close to being correct. Also calculated the inlet area and it is much less than the area for the 3300. I should be fine on outlet area. I to have seen the wicker bill technique used and it is a viable and easy option, should flight testing reveal the need.   

Safe and Happy TG all

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