Steve,
For small deflections you can use: sin(3 deg) * (flap chord)
My flap chord at the root is 10.75", so 0.56" - Another option is a digital level.
The faired-in position is pretty accurate at -7 degrees. When I calibrated my flap position transducer, I had to make a full size template to locate 0 degrees. The
fuselage fairing ended up right at -7.0, so it is a good reference.
When measuring speeds greater that 120 KIAS, I recorded each point for at least three minutes. I found that it took about 2 minutes to reach a truly stabilized speed after a power or flap setting change. The speed decay is so slow it isn't really detectable
by starring at the airspeed indicator. Imagine trying to see average needle movement of 1kt/min. Fortunately the two minute settling time is very consistent.
I think it would be quite valuable and educational to repeat the same series to of tests on a small tail 320/360. I would be more than happy to go over all the details with anyone interested in volunteering. I think the biggest hurdle is mounting the alpha/beta probe. I was able to grab onto the mounting provisions for my wingtip lens with a fiberglass 'lens' to mount the probe. The internal transducers are relatively simple.
Chris Zavatson
N91CZ
360std
From: steve <n5276j@aol.com>
To: lml@lancaironline.net
Sent: Monday, September 30, 2013 5:59 AM
Subject: [LML] Re: Lancair 320/360 performance and stability
Chris, I'm going to re-just my flaps to -10 reflex and see what happens. What would you guess the measurement is up from the trailing edge of the faired in position?
Thanks for all your work. Do you need a small tail 360 for more testing?
Steve Alderman N25SA
-----Original Message-----
From: Chris Zavatson <chris_zavatson@yahoo.com>
To: lml <lml@lancaironline.net>
Sent: Sun, Sep 29, 2013 8:54 pm
Subject: [LML] Re: Lancair 320/360 performance and stability
So I happened to be looking for something unrelated in the FB manual and came across this on page 10-24:
"Lancair flaps are full electric actuated. They are designed to run from +45 down to -10 up (reflex). Note that the 'faired in position' for flaps is actually a -7 deg reflex position. ....."
My standard build manual is in storage so I could not compare. It would appear the intent was to be able to go to -10 degrees after all.
Chris Zavatson
N91CZ
360std
Chris,
today I made a picture during Cruise with Autopilot at 7500ft with following configuration:
770 kg 40l in header, 20l in each wing (80l total),
75kg and 83kg for pilot and co.
Flap was on 7° reflex CG 26,20"
My design CG is 22,8 - 30,3 from firewall back, horizontal was installed - 0.6°
So it looks like if I would add more reflex than 7°, I would need more down elevator.
So the gain with the higher reflex would be lost with the down elevator....
Christian