It appears it uses the same gearing as the Syma x5 models and quite possibly the shafts as well...I would imagine compatible.
I would give it a shot and order some x5 main gear and shaft assemblies and see what happens...I too cannot find just shafts and gears or even a complete motor holder assembly for the h5p.
Syma x5 main gears and shaft assemblies can be found almost anywhere....you might even try a whole x5 motor holder assembly (not x5s or x5w) and if they dont fit properly in the h5p shell you can still try to remove the shaft assembly...They arent easy to disassemble however.
This may be your best bet here to find out if it does in fact work...for $4.00 its worth a shot to get back in the air......
http://m.aliexpress.com/item/326260....4.YGOyxD&tracelog=wwwdetail2mobilesitedetail