Design Improvements for the Zenith 601 HDS: Wing Locker Doors
Wing Locker Doors
Air leakage from the wing locker doors onto the top of the wing
has a significant impact on the lift characteristics of the wing.
This may seem surprising, since the gap between locker door and
wing is small when examined on the ground. But the gap
increases somewhat in flight due to the low pressure on top
of the wing, and the air shooting out of that gap
disturbs the attachment of the airflow to the wing sufficiently
that lift is reduced. There is also air leakage through the slots
of the hinge.
To eliminate the air leakage, we have riveted
reinforcements to the edges of the locker doors and installed
1/8 in. thick, 1/4 wide adhesive foam strips as seals to the locker
doors. We have also added an extruded
L strip below the hinge, topped with foam material. The foam seals
the hinge from below.
The change has significantly improved performance when angle of
attack is high.
For example, at 1,500 MSL and 56 deg F,
climb rate is now for pilot and full fuel (= 900lbs total weight)
1,500 ft/min at 70 kts.
Even at 8,500 ft MSL and 35 deg F,
which corresponds to about 9,500 ft
density altitude, climb rate at the same loading
is 800 ft/min at 70 kts.
For the same case,
power-off optimum glide speed is 55 kts with a 500 ft/min sink rate.
