Mailing List lml@lancaironline.net Message #48528
From: <PTACKABURY@aol.com>
Sender: <marv@lancaironline.net>
Subject: some MORE thoughts on accidents
Date: Mon, 25 Aug 2008 12:08:08 -0400
To: <lml@lancaironline.net>
From Lynn's Legacy to my LIV, also a VERY fine flying airplane--the most efficient cross country cruiser I have piloted.
Flying slow is not for the uninformed, and maybe not for most.  However it helps to understand what show is relative to your favorite plane and what surprises it might bring.  I built a LIV because I wanted a high wing loaded flyer (I had a LongEZ which is also a great cruiser) to save my aging kidneys as I travel across the great American deserts of the west.  I wanted a LIV because I think it has a great wing and flap system that offers a remarkable flight envelop with an amazing spread between stall and top speed.  I wanted an LIV rather than a "P" or Turbine because it could be built light enough to not over tax that 100sqft wing area and retain some agility to keep non cruise flight fun.  I got what I wanted, in spades.
I also wanted to understand the low speed end so I conducted some stall investigations which I will share.  I calibrated my pitot static system with ground and flight test so am reasonably confident the following numbers, in KIAS, are accurate.
1 G stalls, 10k msl, ball centered, level flight, very slow A/S bleed rate:
with stall strips, light weight, clean: 78; gear and full flaps: 70
without stall strips, light weight, clean: 73; gear and full flaps: 68
without stall strips, heavier weight, clean: 77; gear and full flaps: 72
Note:  light weight is me plus 30 gal of fuel
    heavier weight is me plus 75 gal of fuel
    empty weight is 2200 lbs, I am 200 lbs
    CG is towards the fwd limit
    stall strips were two triangle shaped strips 10 inches long mounted 15 inches outboard of the wing root
    stalls were abrupt but straight ahead IF the ball was centered
    stalls with the ball out of the race resulted in abrupt rolls up to 90 degrees of bank
    higher energy stalls (accelerated) resulted in more abrupt departures with rolls exceeding 90 degrees
    no high power stalls were attempted
    warning buffet generally began 1 or maybe two knots above stalls without strips
    warning buffet generally began about 5 knots above stalls with strips
    data were plus or minus about 3 KIAS due to variations in bleed rate and G
So I set my stall warning on the Chelton at 78 KIAS to keep the aural warning silent while touching down.  I fly the pattern about like Lynn and his Legacy--110 around the corner and 100 over the overrun.  Remember your stall margin is increased base to final to touchdown because you are descending and are therefore at less than 1 G.  I am very happy if I can touch down light weight at 80 KIAS--it is easier to get a better landing with a faster touchdown but slower is better pilotage.
I hope that gives everyone an idea of the flight characteristics of a LIV around stall so you can begin to understand what the boogie man looks like.
paul, N94PT
 
In a message dated 8/21/2008 4:53:32 P.M. Pacific Daylight Time, farnsworth@charter.net writes:
If you want to fly slowly, install vortex generators or buy a Piper Cub.




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