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

Pitot Source

Matronics Email Lists Forum Index -> Kolb-List

View previous topic :: View next topic

Author Message

Dennis Kirby

Joined: 05 Dec 2013
Posts: 35
Location: Albuquerque, NM

Posted: Mon Jul 06, 2015 12:51 pm Post subject: Pitot Source

"Stuart Harner" wrote:  << I realized that after the runway was made, I never look at the ASI. >>

Stuart / Kolb Friends -



I'm gonna have to disagree with this practice, primarily if your flight operations are at higher-elevation airfields.  I'll share a story with you that confirms this.



Every fall, our backcountry pilot's club has a fly-in at an abandoned Forest Service airstrip in the Gila Wilderness area of southwestern New Mexico.  This grass strip has an elevation of 8200' MSL.  My friend was approaching to land in his Rans S-12 (powered by a Rotax-912S).  Everything appeared normal for his approach - glide angle and airspeed were as they should be.  At 50 feet above the runway, he technically already had the runway "made."  Suddenly, to all our surprise, at about 20 feet high, the Rans simply dropped out of the air and pancaked onto the grass runway, destroying his landing gear and substantially damaging his aircraft.  Fortunately, my friend was OK.



Here's what happened: He was approaching at the normal airspeed (55 mph) that we typically use for our low-elevation home field of 6500 feet.  (His Rans and my Kolb use the exact same airspeeds for final approach: 55 mph.)  At about 30 feet above the runway, he was looking out, but in his peripheral vision, he noticed the airspeed needle wiggle.  He glanced down at his airspeed indicator, and saw it suddenly drop to about 40.  That's when he realized that the slight headwind he was flying into suddenly disappeared.  In a desperate attempt to regain airspeed, he pushed the stick forward, but it was too late.  His aircraft stalled at 20 feet high, and dropped in.  At this airstrip's elevation, there was precious little airspeed margin above stall speed, and he did not react fast enough.



If he had been keeping an eye on his approach speed, he would have noticed the rapidly-decaying airspeed and might have reacted with forward stick quickly enough to avoid the stall.  It's an easy habit to glance down at your airspeed indicator every few seconds while on final, just to make sure you are still at flying speed.



Sorry for the long post, but it tells a good story.  "Keep thy airspeed above stall, lest the earth rise up and smite thee!"



Dennis Kirby

Mark-3 / 912ul

Sandia Park, NM

- The Matronics Kolb-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kolb-List

stuart(at)harnerfarm.net
Guest

Posted: Mon Jul 06, 2015 5:57 pm Post subject: Pitot Source

Dennis,



Please forgive my lack of explanation. 



When I said "had the runway made", I should have said "had the landing

made". Or perhaps, "at the beginning of the flair".



I watch the airspeed all the way around the pattern and down final until I

am about to flair. At that point, my focus shifts to outside the cockpit so

that I may judge the last few seconds before beginning and throughout the

flair all the way down to touchdown. Also, at that point I am not likely to

look back at the airspeed as I am concentrating on keeping the noisy end

pointed forward and dealing with any crosswind components. Happy rudder

pedal dance and all that.



The question that I had been asked was "at what speed do you touch down in

the Chief?".  I had to think about it, then I realized I had never looked at

the ASI at the actual point of touchdown. In the Aeronca Chief at full flair

the nose was high enough that I learned to glance back and forth at the

horizon and the ground out the left window where I could see the left tire

and the grass scooting by. I could also see the left edge of the runway for

alignment.



Quite a different story in the Firefly. The Chief did not have a lot of

inertia, but it was a freight train compared to the Firefly. In the Firefly

I can see EVERYTHING right in front of me, including the ASI all at the same

time. I generally touch down at ~40 MPH indicated (wheel landings). I am

working my way up to trying a 3 point landing, but not there yet. I can tell

you that Serenity stalls at 36 MPH indicated with no flaps and at 35 with

one notch. I have not tried two notches yet. Approaches are way more fun

with one notch of flaps, but I often forget to use them and just side slip

when needed. That was all I had in the Chief.



In the Chief I used to fly a stable approach from a standard pattern of

800'. Then at flair height, just stop the descent, and keep pulling back

until I ran out of lift. If I did it right, I could plant the tail wheel on

the ground first, the pull the wheel all the way back. At that point it was

not going to float back into the air because it could not rotate and

increase lift. The up elevator helped with additional drag. Then when the

lift subsided, the mains would just settle on as gentle as could be. I wish

I could say all my landings were like that, but they weren't. However,

sometimes they were, usually when there was no one around to see it. 



When in less than ideal conditions I like to keep a little extra speed in

the pattern, especially turns. It sometimes makes for an ugly approach. I

try to opt for safety over style. Gusty or variable winds. High temps or

elevations. Usually not a problem with flying an ultralight as I tend to

stay on the ground unless it is close to perfect.



Hope this clarifies things a little.



Stuart

--

- The Matronics Kolb-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kolb-List

Display posts from previous:

	Matronics Email Lists Forum Index -> Kolb-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