Mailing List lml@lancaironline.net Message #44717
From: <Sky2high@aol.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Needing performance information on the Lancair 200 and 235
Date: Mon, 05 Nov 2007 10:55:23 -0500
To: <lml@lancaironline.net>
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!




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