As well as finishing off most of the fabric covering on the flying surfaces this week, Theo’s taken a look at the wheels.
Almost all WWI aircraft wheels were based on motor cycle wheels with spokes. They were fairly strong, relatively cheap and were easily replaceable. But for aircraft use all those spokes created loads of drag, and so they were covered with fabric. I understand that in those days you could get tyres with little wire loops in the sidewalls to which you could lace the fabric cover.
The Scout didn’t use that system. The drawing says that the motorcycle tyres – ‘heavy motor cycle smooth tread – were wired on. We’re not quite sure what that means, but ours, as bought from the Vintage Motor Cycle club, are beaded tyres, which means that the inside edge of the tyre has a bead which sits inside a groove in the rim.
The instructions for the fabric are; ‘Covering as used on Bristol Monoplane (that must have been the Coandă monoplane, not the M1C) wheels. Side covers sewn to fabric strip round rim.’
We’ve struggled to understand this, but thought perhaps a strip was laid inside the rim underneath the inner tube, which then stuck out each side, to which the main cover was hand sewn.
The trouble with this is that the tyre bead won’t sit as securely in its groove, with the risk that if there’s any sort of drift on landing the tyre will come off, and very likely tip the whole aircraft on its nose…
(Beaded or clincher tyres were famously insecure, and came off at the slightest provocation.)
Other people use Superseam cement to glue the fabric direct onto the rim, but ours seem very small for that and in any case the paint is dissolved by the acetone of the cement, so that idea was kicked into touch.
Another cunning plan used by others is to use a ply ring (about 25mm wide) round the outside to which the fabric is glued. Holes are drilled in the ply so that the two – inside and outside – can be stitched together through the wheel spokes using standard ribstitching techniques. The knots in the ribstitching won’t be entirely authentic, but will replace the hand stitching that was on the originals, and the covers can easily be removed and replaced if they get damaged, and that’s the cunning plan we’re working on now.
We’ll let you know how things progress.