Tuesday, September 6, 2011
The Best Of All Possible Worlds
Four if by land, two if by sea: making a great plane greater
The AmpibCub is outfitted with metal Baumann BF 1500A floats; the LSA standard allows an additional 110 pounds over the max legal weight of 1,320 pounds, increasing max takeoff weight to 1,430 pounds.
On a beautiful spring morning, we roll down the runway and rotate (10 seconds) at around 45 mph. The ASI is marked in miles per hour, not knots. It’s a Cub, after all. I see 750 fpm climb at 60 mph. “Everything works good around 60 mph,” says Sehnert. “Climb out, best glide, and it’s a good approach speed. I always tell people, ‘If it all goes bad, find 60 mph first.’”
We climb east as Sehnert shares his deep Cub experience. “I tell people, ‘The bad news is, the Cub’s kind of a draggy airplane. And the good news is, the Cub’s kind of a draggy airplane.’ Even adding floats, you’re not really changing the airplane’s drag profile because you’re also taking off landing gear and struts, and it all kind of balances out.”
Flying the AmphibCub is pretty much like flying a Cub. The control inputs require firmness, and response in pitch and roll are smooth and steady and, all in all, no surprises. About the only difference is a slightly heavier control feel and a stable-feeling sense of a lower center of gravity from the mass below the airplane, which helps ride out the bumps a little better than the lighter land Cubs.
Floats also impart some pendulum stability. Pulling turns, everything feels familiar, rock-solid and friendly to me—pure Cub pedigree.
We run through a full stall series—a real hoot. Power-off stall comes at 33 mph with the dual sticks buried in our manly bellies. The nonevent maneuver delivers a mild falling-leaf descent at about 550 fpm with minimal rudder to keep things centered up.
Power on: That’s a roller coaster ride.
Our pitch-up angle exceeds 45 degrees at 40 mph! Again, the sticks are buried. Quick pushes on the rudder keep the mild rock and roll under control. Recovery is a slight nose over and...“That’s it,” says Sehnert...the Cub’s flying again.
For fun, we do an aggressive accelerated turn at a high bank angle: Back on the power; dropping through 50 mph; back, back, back on the stick; there’s the buffet—but the AmphibCub hangs solid in the turn. Yes!
A thin stream of morning dew drains out of the wings as Sehnert regales me with stories of a classic bush pilot mistake: the “moose stall.”
“They’ll see a moose, start circling to check it out...and stall the airplane. If you as a pilot don’t notice that the airplane’s buffeting hard, telling you what’s going on, well you have to be awfully excited; that must be one heck of a moose!” Maybe a Sarah Palin trophy moose?
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