Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

VG generators

Matronics Email Lists Forum Index -> Kitfox-List

View previous topic :: View next topic

Author Message

clint_bazzill(at)hotmail.
Guest

Posted: Sun Apr 26, 2009 9:17 pm Post subject: VG generators

Hi all C

  

 When testing for stall speeds C power off will not work with most Kitfox'es.  There is just not enough elevator control and it will go into mush.  Test with enough power to detect stall...  I have the vg's under stab.  Over size model IV elevator and gap seal.  The AC stalls 5 mph slower with them.  10 percent position of mc C that includes flaperons.  Did tuff test with Air Cam as chase plane. Video recorded and any position  around 10 percent would work well.  I have calibrated my airspeeds and it these numbers that I used.

  

 These are TAS

  

 Stall speed clean without generators.  48 mph

  

 Stall Speed with flaps no generators 43 mph

  

 Stall Speed with generators no flaps 43 mph

  

 Stall Speed with generator full flaps 38 mph

  

 I did not list these in past as temp C altitude etc were all in this data.  What I listed is a brief summary of what was done.  It's reduction in stall is just about what most VG's on AC do.

  

 Clint

  

 Model IV-1200

  

 1450 hours 912-ULS

  [quote][b]

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Mon Apr 27, 2009 9:23 am Post subject: Re: VG generators

Clint those are high stall speeds,  what does your plane weigh ? 

is it SPeed wing ?

_________________
Realtime Kitfox movies to separate the internet chatter from the truth
http://www.youtube.com/user/kitfoxflyer
Hundreds of Kitfox Movies
Most viewed Kitfox on youtube
Most popular on youtube
Highest rated on youtube

lcfitt(at)sbcglobal.net
Guest

Posted: Mon Apr 27, 2009 11:54 am Post subject: VG generators

Hi Clint,



For some reason I don't follow your test procedure and the goal of the test. 

Most people when trying to land short will use power off to a three point. 

With this configuration, vortex generators on the wings don't drop the stall 

speed significantly.  Are you suggesting that to land really short, to carry 

a little power to flair in order energize the elevator to stall at a slower 

speed.  It sounds a bit counter productive.



Is it your procedure to approach with power off, then add a bit of power 

just before the flair?  Busy.



It seems to me that if in order to energise the elevator you need a bit of 

power, there is something wrong with the horizontal stabilizer / elevator 

design or geometry, or maybe a W/B issue.



Lowell Fitt

Cameron Park, CA

Model IV-1200 R-912 UL

Still building



---

clint_bazzill(at)hotmail.
Guest

Posted: Mon Apr 27, 2009 12:35 pm Post subject: VG generators

Hi Lowell C

  

 That is one way to land short. But not shortest.   Watch bush pilots land.  They carry quite a bit of power C they are flying on the back side of power curve.  They touch  down and cut power.  With power off in a Kitfox  C you probably will drop the airplane and be landing a lot faster.   With power off trying to land C not enough elevator C critical timing and probably a rough landing.  Got to get the airspeed slow and hold it there until touch down.

  

 Clint

  

 P.s. that 5 mph that you can fly does a lot.

  

  

 

[quote] From: lcfitt(at)sbcglobal.net

 To: kitfox-list(at)matronics.com

 Subject: Re: VG generators

 Date: Mon C 27 Apr 2009 12:53:18 -0700

 

 --> Kitfox-List message posted by: "Lowell Fitt" <lcfitt(at)sbcglobal.net>

 

 Hi Clint C

 

 For some reason I don't follow your test procedure and the goal of the test. 

 Most people when trying to land short will use power off to a three point. 

 With this configuration C vortex generators on the wings don't drop the stall 

 speed significantly. Are you suggesting that to land really short C to carry 

 a little power to flair in order energize the elevator to stall at a slower 

 speed. It sounds a bit counter productive.

 

 Is it your procedure to approach with power off C then add a bit of power 

 just before the flair? Busy.

 

 It seems to me that if in order to energise the elevator you need a bit of 

 power C there is something wrong with the horizontal stabilizer / elevator 

 design or geometry C or maybe a W/B issue.

 

 Lowell Fitt

 Cameron Park C CA

 Model IV-1200 R-912 UL

 Still building

 

 ---

clint_bazzill(at)hotmail.
Guest

Posted: Mon Apr 27, 2009 12:43 pm Post subject: VG generators

For a good short field landing C you fly the aircraft as slow as possible C with power to touch down.  You adjust power to control altitude C elevator for airspeed.  Check this video out for a demo.  That extra reduction in airspeed is important.

  

 Clint

  

  

 http://www.youtube.com/watch?v=sfeMLQNe57E

 

 

[quote] From: lcfitt(at)sbcglobal.net

 To: kitfox-list(at)matronics.com

 Subject: Re: VG generators

 Date: Mon C 27 Apr 2009 12:53:18 -0700

 

 --> Kitfox-List message posted by: "Lowell Fitt" <lcfitt(at)sbcglobal.net>

 

 Hi Clint C

 

 For some reason I don't follow your test procedure and the goal of the test. 

 Most people when trying to land short will use power off to a three point. 

 With this configuration C vortex generators on the wings don't drop the stall 

 speed significantly. Are you suggesting that to land really short C to carry 

 a little power to flair in order energize the elevator to stall at a slower 

 speed. It sounds a bit counter productive.

 

 Is it your procedure to approach with power off C then add a bit of power 

 just before the flair? Busy.

 

 It seems to me that if in order to energise the elevator you need a bit of 

 power C there is something wrong with the horizontal stabilizer / elevator 

 design or geometry C or maybe a W/B issue.

 

 Lowell Fitt

 Cameron Park C CA

 Model IV-1200 R-912 UL

 Still building

 

 ---

Fox5flyer
Guest

Posted: Mon Apr 27, 2009 1:19 pm Post subject: VG generators

Agreed.  That is some extreme short field work.   Good video, however, all that wind probably helped a lot.

 I learned about approaching behind the power curve a long  time ago and it works.  I have a short farm strip and I always (try to)  land with power on, nose high, and very slow which allows a steep  approach.  When I chop power and retract flaps all flying is done so I need  to be very close to the ground before I do it.  It takes a lot of timing  and practice and if I get it just right, I'm down and stopped in just  a couple hundred feet.    Turbulence, cross winds, etc tends to  require some modifications, but most of the time it gets me in very short, even  with my heavy (880lb) S5 with no VGs.   

 Deke Morisse

Mikado Michigan

S5/Subaru/CAP 405+  TT

"The aim of an argument or discussion should not be victory, but  progress."

- Joseph Joubert

  

 ---

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Mon Apr 27, 2009 1:53 pm Post subject: VG generators

At 01:33 PM 4/27/2009, you wrote:

 	  Quote: 	
		  That is one way to land short. But not shortest.


	


I suspect that ideal would be to land power off, but I've found it 

impossible to hit the bulls eye at zero vertical velocity and at 

stall. There's just way too much going on. After watching Mark and 

Hal slaughter everyone at the last spot landing contest I came to the 

conclusion that Clint's method was the only way it was going to 

happen. My only problem with it is that it requires a very careful 

assessment of gust factor. When you're pulling it in low and slow the 

last thing you want is a 5-10 mph drop in head wind with the 

subsequent stall. And since the stopping distance varies as the 

square of the initial velocity, (assuming a constant deceleration) 

Clint's right, the extra 5 mph is significant.

 	  Quote: 	
		  

P.s. that 5 mph that you can fly does a lot.


	


(38/43)^2 = 78% of the distance to stop.

(38/4^2 = 63% of the distance to stop.

Guy Buchanan

San Diego, CA

K-IV 1200 / 582-C / Warp / 300 hrs. and counting

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

lcfitt(at)sbcglobal.net
Guest

Posted: Mon Apr 27, 2009 3:11 pm Post subject: VG generators

You got me there, Clint.  I guess I am just not a bush pilot.  I probably 

fit in the catigory of most pilots.  I am aware of the technique and likely 

will try it once I am flying with the lift reserve indicator.



Lowell



---

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Mon Apr 27, 2009 4:05 pm Post subject: VG generators

I was trained to always do complete power off (idle) landings.  When I

started flying the Kitfox I also started giving a shot of power at the flare

to level things off just before touchdown.  Some times I would add power and

actually fly the plane onto the water.  I actually started getting angry

with myself for using the power that way.  Although it is a good procedure

for "glassy water".  

What I found helped me get out of what I considered to be a bad habit was to

try to make every landing as short as possible.  I also started carrying a

little more speed into the flare via a little steeper angle of descent.

The extra speed gave me more control to the flare.  The idea is to have the

wing stall at the precise second the floats touch the water.   Most landings

I am at full elevator up at the moment of touchdown.  Once down I'll release

the backpressure on the stick slightly to prevent the plane from porpoiseing

during the run out.



I have in light winds, enough wind to tell where the water was, been able to

get the plane down and off step in around 300 ft..  I once landed a super

cub on EDOs downwind (3-6kt) in around 600 ft.  I was so far from the dock I

took off flew half the length of the pond and landed again close to the

dock.



 True glassy water conditions usually take about a mile or so. I round out

with a bit of power on just above the trees. And basically fly the shoreline

while descending slowly with the power on in a nose high attitude.  When the

floats hit the water I slowly reduce power to the point where I can maintain

a step taxi.



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

clint_bazzill(at)hotmail.
Guest

Posted: Mon Apr 27, 2009 7:25 pm Post subject: VG generators

My plane weighs 670 lbs.  Started out at 634 C added a lot of stuff C wouldn't remove anything I put on.  Those are real numbers C not indicated air speeds.  Matches pretty close to the kitfox books.

  

 Clint

 

 

 	  Quote: 	
		   Subject: Re: VG generators

 From: dave(at)cfisher.com

 Date: Mon C 27 Apr 2009 10:23:59 -0700

 To: kitfox-list(at)matronics.com

 

 --> Kitfox-List message posted by: "dave" <dave(at)cfisher.com>

 

 Clint those are high stall speeds C what does your plane weigh ? 

 is it SPeed wing ?

 

 --------

 Rotax Dealer C Ontario Canada

 http://www.cfisher.com/

 Awesome *New Forum *

 http://rotaxaircraft.com/forum/

 Realtime Kitfox movies to separate the internet chatter from the truth 

 http://www.youtube.com/profile_videos?user=kitfoxflyer

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=241471#241471

 

 = Archive Search & Download C 7-Day Browse C Chat C FAQ C

&g====
	


[quote] 

 

 

   	  Quote: 	
		  [b]

akflyer

Joined: 07 May 2007
Posts: 574
Location: Soldotna AK

Posted: Wed Apr 29, 2009 5:08 am Post subject: Re: VG generators

We were out playing on the beach a couple days ago.  The KF did a lowell approach, mine was more of a clint approach.  The cross wind did not make for ideal use of full flaps, but you will get the idea.



http://www.youtube.com/watch?v=3bddee4CSqg

three on the beach small.jpg

Description:

Filesize:

253.97 KB

Viewed:

7630 Time(s)

_________________
DO NOT ARCHIVE
Leonard Perry aka SNAKE
Soldotna AK
Avid "C" / Mk IV
582 (147 hrs and counting on the rebuild)
IVO IFA
Full Lotus 1450
#1 snake oil salesman since 1-22-2009

I would rather die trying to live, than to live trying not to die....

Display posts from previous:

	Matronics Email Lists Forum Index -> Kitfox-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum