The recent show on the monster P-38 that was built by a young man highlighted the ultralight construction, but didn't really reveal how they were lightened. I saw some open ribs under the wing, so that is one clue, but I suspect there are many lessons to be learned from the builder on how to build a lightweight plane. Could we have this builder share some lightweight building tips in a future show? The kid is obviously a budding genius and has much to teach us. Those Fowler Flaps were awesome.