Fuel cap replacement / Shaw Plug / Snap Tite

[DCASonex]

The Usher looks interesting if it fits and if its O ring is not too far down for short necked tanks. Its low height above tank neck would be great for anyone fitting a new (old style) tank by eliminating need to trim the height of the neck. Longer is better.

Word of caution to anyone thinking of making one of the expanding O ring style fuel caps: The old Sonex supplied Shaw Snap Plug (wine bottle stopper) will conform to the shape of the tank's neck even if out of round, and cannot provide enough force to damage the neck of the tank. The expanding O ring type will force the tank neck into a round shape, and even thought the forces it can generate are not as high as the devices used to expand steel exhaust pipes, the principle is the same so take care not to over tighten. Also remember that rotational molded tanks are like snowflakes, no two are exactly identical and will need to carefully check your specific tank and tweak design accordingly.

David A.

[DCASonex]

It works? Weather finally allowed getting plane out of hangar and some flying time. First flight in three years that did not have even a hint of fuel in cockpit even with vents closed. (its still winter here and I do have a Guardian CO detector) First tested by filling tank and lifting tail while observer watched for leaks. Very low force required for good seal, only about two turns of knob from fully backed off position. My design is only for those with a machine shop, too much time on there hands, and an urge to make chips, but the other two designs that re-used the cam mechanism from the wine-bottle-stopper Shaw plugs should work as well and much easier to make, lathe still required. Do have drawings and photos of mine if anyone is looking for ideas, will need to customize for each individual tank. Getting depth of O ring correct looks to be very important, especially for short tank necks. Thanks again to all for the idea.

David A. Sonex TD

[SonexN76ET]

David,

I am going to order some of the buna nitrile rubber inserts for my fuel cap from Shaw like you did. Did those work ok in your Sonex fuel cap? In the long run I may look at making a fuel cap like your's with the o-ring compression. That looks like a good solution.

Jake

[DCASonex]

David,

I am going to order some of the buna nitrile rubber inserts for my fuel cap from Shaw like you did. Did those work ok in your Sonex fuel cap? In the long run I may look at making a fuel cap like your's with the o-ring compression. That looks like a good solution.

Jake

Jake,

Now that I know my O ring cap works so well would be happy to sell you some of the Shaw Buna-N replacements I just bought, Shaw's minimum order is 5 at $15 each plus $22 shipping which was about $20 each. I will sell you a few at $10 each, no minimum order and even throw in one complete operating assembly of which I also have a couple to spare. USPS priority mail should be much less expensive than what Shaw charged. Contact me via private message with your shipping address if interested.

David A.

[RodgerC]

The final version, lower profile for extra clearance, shallower insertion depth for short necked tanks ( like mine) and knurled for better grip and because it just looks cool!...I can see an extra Aeroconversions product line being considered :P

[GordonTurner]

Hi Rodger

I wish you'd consider a side business manufacturing those caps. That thing is gorgeous!!

Gordon

[Bruce593SX]

I would buy one...

[peter anson]

Here's a slight rearrangement of Roger's design.

The taper is on the top part of the cap which I found made the cap a bit easier to remove, and operation is by a wing nut and knurled lock nut instead of the lever.

Peter

[peter anson]

Here's a slight rearrangement of Roger's design.

The taper is on the top part of the cap which I found made the cap a bit easier to remove, and operation is by a wing nut and knurled lock nut instead of the lever.

Peter

[GordonTurner]

Hi Peter

Are you going to be selling those?

Gordon