Building on a discussion I've been having with FritzW offline...
The Evans Volksplane VP-1 and VP-2 are great examples of simplified design and construction, but there are some down sides. One of those is the attachment of the shoulder harness to bolts in the rear spar bulkhead about the height of the pilot's shoulder blades. That is really too low, both allowing a lot of forward motion and compressing the spine in a crash.
Does anyone have any thoughts on a relatively simple and lightweight way to raise the harness attachment points about 6" above the top of the spar bulkead? Keep in mind that we are talking about a lot of force on those points in a crash, maybe 100 lb (upper body weight) x 20G, double that for the VP-2 with two aboard.
I have thought about raising the spar bulkhead (and matching turtledeck) but that would require substantial reinforcement, perhaps cables from the harness attachment points to an anchor point near the tail, to keep from just snapping off the top of the bulkhead in a crash. Perhaps the simplest option would be to add a little "roll bar" to the rear spar bulkhead, similar to the one that forms the canopy frame, but that, too, would require some thought as to how to brace it against the forces in a crash. Fritz suggested two such bars like an rally race car, but I think that would look odd as the VP-2 is flown solo from the center.
Cheers,
Matthew
The Evans Volksplane VP-1 and VP-2 are great examples of simplified design and construction, but there are some down sides. One of those is the attachment of the shoulder harness to bolts in the rear spar bulkhead about the height of the pilot's shoulder blades. That is really too low, both allowing a lot of forward motion and compressing the spine in a crash.
Does anyone have any thoughts on a relatively simple and lightweight way to raise the harness attachment points about 6" above the top of the spar bulkead? Keep in mind that we are talking about a lot of force on those points in a crash, maybe 100 lb (upper body weight) x 20G, double that for the VP-2 with two aboard.
I have thought about raising the spar bulkhead (and matching turtledeck) but that would require substantial reinforcement, perhaps cables from the harness attachment points to an anchor point near the tail, to keep from just snapping off the top of the bulkhead in a crash. Perhaps the simplest option would be to add a little "roll bar" to the rear spar bulkhead, similar to the one that forms the canopy frame, but that, too, would require some thought as to how to brace it against the forces in a crash. Fritz suggested two such bars like an rally race car, but I think that would look odd as the VP-2 is flown solo from the center.
Cheers,
Matthew
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