jmb52760, I don't know enough about the S72, but that's interesting about the 'virtual' airfoil. I had considered an oval shaped airfoil, as an evolution of a round airfoil, or a double ended symmetrical airfoil, which would seem to answer the requirement with one important exception:- The round one doesn't generate any lift! Is there any wind tunnel data on oval airfoils?

By the way, don't think I didn't notice the Boeing Dragonfly. I use it as my avatar on another forum!

B.L.E., I agree that virtually any airfoil shape, even a clark Y, will lift forwards, backwards, upright or inverted, but center of pressure and pitch moments would change so dramatically that stabilising it would be a nightmare. That is part of the reason for searching for a unique airfoil which would offer consistant behaviour in those differing flight regimes.

Yep, the 3D guys go backwards, briefly! I haven't yet seen one that can sustain reversed flight and maneuvre as it does in forward flight. I reckon this would take it to the next level, if it can be accomplished.

jmb52760, Let's not bring helis into this. Anyhow, I don't think the Szabo's have any respect for physics! Hehe.

BMatthews, Control surfaces are another of those "other things to consider" that I mentioned in my first post. All flying stabilisers sounds good to me, but again, airfoil selection for these will be important for proper balance. I feel reluctant to attempt changing C of G, or wing position, in flight. My gut tells me to avoid it. In the end, it may be unavoidable.

I imagine flying toward a mate for a Zagi catch and just before he grabs it, slam it into reverse and fly away backwards, with a roll and a loop, just to stamp your authority on proceedings. Should be a hoot! Flying and maneuvring a plane backwards would be challenging, I think. Remember the old days when helis used the 'invert switch'? Nowadays, pilots just do it, switchless. Flying planes in reverse switchless should add an interesting new challenge to 3D flying.

I'm encouraged by all the interest, thanks, but I think we still need that unique airfoil. I'm all ears!

Cheers from the Barfly.