Carbon fiber cowlings Mk2 Kitfox

[firesteve]

Here in the Uk only the Mk 1&2 Kitfox is eligible to be flown as a microlight. I managed to find a Kitfox 2 for a reasonable price but was looking a little tired from when it was built way back in 1992. The aircraft had undergone a refit in the engine department having had a Jabiru 2200a fitted by the previous owner. Although the engine had been fitted very well other parts of the aircraft affected by the retrofit, namely the cowling were not so nicely done.
As I'm sure you are aware the fitting of a Jabiru engine involves extending the nose of the aircraft by four inches, extra fiberglass had been added but the whole thing just didn't sit right!
I decided early on that I would go for a more 'modern look' and attempt to construct my own cowlings from carbon fiber, he is how I'm getting on so far,,,
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Aircraft as purchased, nice flames!!!
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Cowling with stickers removed, not the nicest of finishes!
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Plug taking shape, experimenting with designs.
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Top cowling plug to rough shape.

[firesteve]

Having made the rough plugs from expanding foam and finished with car filler, molds in fiberglass were made in order to make fiberglass 'intermediate' plugs. By doing this it allowed the plugs to be fitted to the aircraft and allowed much more manipulation as the fiberglass is much stronger.
Once I was happy with the design i finished the detailing using car body filler and another set of molds were cast from these plugs in order to facilitate replication in carbon fiber.13022

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[firesteve]

Once I had made the molds of the 'intermediate' plugs I was ready to lay up the carbon fiber,,,

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The finished articles is extremely strong coupled with the fact they are also extremely light! They are going to be painted which is why we did not take too much time on the aesthetics with regards to the 'lay up' of the carbon.
Next step is to remove the engine, bulkhead and strip the old paint off the tubing. The fixings for the cowlings will be sorted once the new bulkhead has been fitted.

[David47]

Yes the original engine cowling looks a bit sad. But very nice job on the new carbon cowl. Making molds, especially from scratch is a bit of an art form, and the cowling lines you've adopted make the front end look much more contemporary. Congrats on the work you've done and on the new look.

[HighWing]

Very impressive work and the design is really nice too. I suspect you have some experience with composites. The vacuum system likely saved a pound or two at least. These are the times I wish we were all living within walking distance, or at least Kitfox distance. It would be great seeing it in person.

[DesertFox4]

Excellent work Steve. I am just getting a small taste of carbon layup. Interesting process. Lots of work with very satisfying results weight wise. Congrats.

[efwd]

That is very nice. That changes the airplane entirely in my opinion.
Eddie

[mr bill]

Really well done.

[firesteve]

Thank's gents for your kind remarks. The process of making the cowlings in time alone was huge (two months), you get quite despondent working on a piece like the plugs which you know ultimately gets thrown away!

The carbon vacuum bagging process was an interesting process to get your head around, like most things it's all in the preparation. The carbon fiber itself is quite good value but the 'fire resistant' epoxy resin was very expensive, it costs you when you make a mistake!

I have to make a spinner and backing plates still but I have moved on by stripping back to the framework so I can assess the condition and repaint the whole fuselage, shame really as the covering is really quite good.

I'm also looking at beefing up the front carry through tube as mine is a bit worn by constant wing folding in the past and also extending the tail fin and rudder.
The pain is I have to get my LAA inspector to do the final welding as he is registered with the CAA, I'm not allowed to despite having all the equipment and years of experience!

[David47]

Are you also going to strip the fabric from the wings as well ?. For mine, I'd be interested in knowing the condition of all wing structural elements as well. I know it means stripping yet more fabric, but that's a small price to pay for having piece of mind that everything has been checked - and replaced or reworked if necessary. Just a thought.

[firesteve]

I think I may have to anyway, having a closer look at some of the underside ribs it looks as if some of the fabric has become detached at some point. Not too much of an issue I hear you say but,,,,,,,,

It looks as if the previous owner has stapled the fabric back on using a staple gun!

I'll let you know what I find when I get that far.

[Peter_SE]

Really nice job on the cowling, i plan to do the same on my model 2 to save some weight. What kind of carbon fiber did you use?, when i looked around there is different types of weight per m2

[TJay]

So what does a Carbon fiber cowl weigh?

[jmodguy]

Looks great Steve! I can attest to your struggles as I did the same with my Series 5. Lots of work that you can be proud of. And it’s DIFFERENT!!!!!!