Hi there, yesterday I started to build a model to get a fibreglass mould for wheel fairings (rear) for my Seagull mc2. It would be easier to buy a couple of ultralight aircraft fairing (pretty cheap, about 50 euros each) but they are too small for wheelbarrow wheels. The fairing is going to be symmetrical.








Very lazy in these days. First I thought of filling the cells with polyurethane foam, but it's not so easy to work and trim when hard. Flat parts are easy to cover with thin plywood, more trouble with the round parts on the top and on the leading edge. I don't want to build too much ribs to fasten the plywood.

Any advice? Wire mesh? Plenty of ribs? Thank you.

Cheers - Enrico

Perhaps try white expanded foam, the stuff that fridges come packed in? You can get large amounts at places like Clark Rubber. The only caveat is that you must use epoxy, rather than polyester when making a mould.

Hiko said...
We decided at the time that the slot where the wheel went into the fairing was the problem so I think that particular attention should be paid to that area
Cheers Hiko

I remember a model airplane nut who did similar testing, and he came to a similar conclusion... he found that the critical part was the distance between the fairing and the 'axle'. The axles in this case are plate spring steel, which run vertically parallel to the wheel before bending inwards and attaching to the fuselage.

By adding and removing washers to change the gap he found a massive difference in drag. He eventually found the best solution was no fairings, with a certain gap between the 'axle' and the naked wheel.

Not sure if it applies here though... you may find that adding golf ball dimples to the fairing might help create a better boundary layer, similar to how Mythbusters tested dimples on a car.



(fast forward to 2:00 or so)