In a message dated 11/5/2007 8:10:28 A.M. Central Standard Time,
kneadedpleasures@sbcglobal.net writes:
A close friend has a pristine Lancair 200 that he has asked me to fly
and then render opinion on the aircraft's performance. It
looks great and has obvious excellent workmanship in its construction.
After a thorough annual condition inspection, I flew it and found that it was
seriously lacking in power. In fact, with just 10 degrees of flaps and
gear extended, it never accelerated beyond 60 knots (though it was
simultaneously rising at about 400 ft per minute). I didn't immediately
retract the gear because I was concerned that the plane was flying just above
stall. In the traffic pattern, I retracted the gear and got just 78
knots - still with 10 degrees flap. I landed uneventfully.
There was no abnormal balance or control of the airplane and, in fact, its
construction symmetry is nearly perfect. Jack test of the landing gear
showed completely flush retract of gear and doors - not likely that something
was dragging. This plane has an 0200 engine with 9 to 1
pistons producing some extra horsepower; perhaps a total of 115.
Its prop is a light weight (27 lbs) cockpit adjustable, electric
IVOPROP.
Does performance sound right for such an early version
aircraft? Who has had experience in these underpowered planes?
What performance numbers should we be seeing? Without more power and
speed, I would be reluctant to take on a passenger for
flight.
Greg,
I am sure actual 200 drivers will comment. Generally, the wing in
cruise expects the flaps to be reflexed 7 degrees up from the chord line.
The 200 series aircraft had the fuselage to flap fairing set at zero
degrees. Thus, cruise requires the flap to be above the fairing (in
reflex). Above certain speeds (140 Kts?) they should definitely be in
reflex.
If your extension of them was to 10 degrees down from the faired in
position then it may well have been more like 17 degrees down from the reflex
position. This is probably the borderline condition where nothing much is
added to wing performance and the flaps are merely adding drag. Watch out
for the trim change when the flap angles are changed - it is potent.
Take off flaps are usually recommended to be about 10 degrees down from
reflex or just 3 degrees below the fairing. (BTW, 300 series fairing is to
the flap in reflex).
Maybe the prop is just not producing the needed thrust.
Scott Krueger
AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL
(KARR)
Darwinian culling phrase: Watch
This!