Re: Alum. header tank question. KF IV
Parts and supplies are arriving daily. I have a question on gluing the aluminum flange to the belly fabric. I assume you glue the flange to the fabric from the inside and glue a patch around it with at least a 1" overlap? Or would you cut a hole for the neck of the flange and glue from the underside? Gluing on the inside makes more sense to me.
Re: Alum. header tank question. KF IV
The flange goes on the inside with a fabric patch like you said. I haven't done mine yet, but gluing it to the inside makes sense.
For my drain I fabricated an aluminum piece that will go on the outside of the plane. It is like a large washer and I will screw or rivet it to the flange through the fabric. Part of my thinking was that I don't want any fuel smell getting back into the cockpit after draining the header tank. It would also keep the fabric from rubbing on the flange if the glue doesn't hold. I will cut the hole in the fabric and install it after painting.
Another thing I did was drill a 1/4" hole through the flange and washer where the drain line from my fuel pump will pass through.
Re: Alum. header tank question. KF IV
Thanks Phil. You're talking about a reinforcing ring on the outside?
Re: Alum. header tank question. KF IV
Correct, I will be reinforcing the flange with a ring outside.
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Re: Alum. header tank question. KF IV
that's not the way I did it. This was done with John Mcbean watching ever so closely. there is sealant under the flange also. Remember, when you sump the drain, you are putting upward pressure on the flange. I think you can do it the way your talking about as well, but there you are, ... experimental.
Re: Alum. header tank question. KF IV
I have just attached this on our K7 build and the instructions are very clear about gluing it to the inside with Poly Tac and then covering with a doily on the outside. it also says to cut a cross slit to open it up and glue the 'ears back inside the flange. It takes a little careful trimming to get the supporting radiator hose the right shape to fit neatly with the tank and the flange.
cheers
Ross
Mt Beauty
Vic
Re: Alum. header tank question. KF IV
Re: Alum. header tank question. KF IV
I used the "what if" approach. What if the drain valve does not seal and starts to drip? Do I want the fuel to wick down the tube and possibly work its way inside the aft fuselage; or, is it better to dribble down the tube and vent fuel to the outside?
With that in mind I put the tube in from the outside of the fabric.
John P
Re: Alum. header tank question. KF IV
I thought of that too John. But as this fabric is already finished I was worried about the possible lack of adhesion between the flange and painted fabric. As I've seen how much the fabric can flex in flight so I'm worried it may pull loose. I was thinking about only clamping the hose to the flange and not the header tank to allow some movement. As far as a leaky sump drain, that's what condition inspections, pre-flights, and a good inflight panel (and fuel level) scan is for. IMO. Unlike a missing fuel cap, a cracked sump o-ring would be a minor leak. To be honest, nothing scares me like the thought of flying behind a two stroke. I know, they've been around and flying for decades, but I can't shake that feeling...
Re: Alum. header tank question. KF IV
Maybe this is off topic, but, I could use some enlightenment. It seems like the header tank, particularly the plastic one, is a problem area for a number of reasons. Can anyone provide the history of why the header tank is used, and what the pros and cons would be for keeping it versus just eliminating it. Since the kitfox is a high wing gravity flow system, why is it needed?