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Short Field Landing Airspeed Conundrum

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Short Field Landing Airspeed Conundrum

Old 12th Jul 2017, 02:55
  #21 (permalink)  
 
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Perhaps pick a bigger more suitable landing area or get a Helicopter license.....

If it's an emergency then it's still better to run into the rough the other end at 20 kts than stall and drop a wing and cartwheel at 100' on final trying to be smart.

Follow the POH techniques.

Or even better try not to get yourself into a situation where you "need" to land at an Airstrip that ain't long enough in the first place.......now there's a novel idea.
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Old 12th Jul 2017, 03:46
  #22 (permalink)  
 
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Originally Posted by ACMS View Post
Perhaps pick a bigger more suitable landing area or get a Helicopter license.....

If it's an emergency then it's still better to run into the rough the other end at 20 kts than stall and drop a wing and cartwheel at 100' on final trying to be smart.

Follow the POH techniques.

Or even better try not to get yourself into a situation where you "need" to land at an Airstrip that ain't long enough in the first place.......now there's a novel idea.
It might not be a case of needing to, it might be a case of just wanting to.
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Old 12th Jul 2017, 04:03
  #23 (permalink)  
 
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So you advocate landing at a strip too short for your Aircraft because you wanted to.

Ok then I'll watch from the sidelines with my camera, good luck..
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Old 12th Jul 2017, 05:21
  #24 (permalink)  
 
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Originally Posted by Lead Balloon View Post
Doesn't stall speed coincide with the stall angle of attack, and the stall angle of attack coincide with the maximum lift coefficient?
Close, but no cigar!

Stall angle of attack is greater than that for max lift coefficient for obvious reasons. Even textbooks get this wrong sometimes, you need to look at polar curves.
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Old 12th Jul 2017, 05:24
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Originally Posted by ACMS View Post
Perhaps pick a bigger more suitable landing area or get a Helicopter license.....

If it's an emergency then it's still better to run into the rough the other end at 20 kts than stall and drop a wing and cartwheel at 100' on final trying to be smart.

Follow the POH techniques.

Or even better try not to get yourself into a situation where you "need" to land at an Airstrip that ain't long enough in the first place.......now there's a novel idea.
There is a whole industry in North America around stol aircraft, for FUN!
Not everyone wants to cruise around in a spam can or plastic speedster.
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Old 12th Jul 2017, 05:36
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Originally Posted by Tankengine View Post
Close, but no cigar!

Stall angle of attack is greater than that for max lift coefficient for obvious reasons. Even textbooks get this wrong sometimes, you need to look at polar curves.
And what is your definition of "stall"? Your "obvious reasons" are "obvious" in the case only of the intuitive definition of "stall".

You'll forgive me if I continue - for the time being at least - to believe that the authors of Aerodynamics for Naval Aviators got it right.
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Old 12th Jul 2017, 05:47
  #27 (permalink)  
 
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Originally Posted by ACMS View Post
So you advocate landing at a strip too short for your Aircraft because you wanted to.

Ok then I'll watch from the sidelines with my camera, good luck..
Been doing it for over 55 years, never scratched one yet.
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Old 12th Jul 2017, 06:08
  #28 (permalink)  
 
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authors of Aerodynamics for Naval Aviators got it right.
Sure did: power for slope and pitch for speed.
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Old 12th Jul 2017, 06:16
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How would you adjust speed in a glider, Cap'n?
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Old 12th Jul 2017, 06:28
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As I said, on and on and on... Go for a walk, LB.
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Old 12th Jul 2017, 07:08
  #31 (permalink)  
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Doesn't stall speed coincide with the stall angle of attack, and the stall angle of attack coincide with the maximum lift coefficient?

Hurt tells a good story. However, g is very relevant to what goes on betwixt IAS and stall so one really needs to specify just what is what for the stall.
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Old 12th Jul 2017, 09:13
  #32 (permalink)  
 
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Originally Posted by Lead Balloon View Post
And what is your definition of "stall"? Your "obvious reasons" are "obvious" in the case only of the intuitive definition of "stall".

You'll forgive me if I continue - for the time being at least - to believe that the authors of Aerodynamics for Naval Aviators got it right.
Believe what you like, in this case wrong.
Didn't know you were a naval aviator (that is a promotion from pilot right?)
Some people do have an odd idea of what a "stall" is, might explain some of the instructional techniques out there!
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Old 12th Jul 2017, 09:49
  #33 (permalink)  
 
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Tankengine:----yes I agree there is a range of STOL Aircraft but they have approved techniques in the POH to do their STOL landings with P charts to suit.

A standard lightie doesn't.
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Old 12th Jul 2017, 10:42
  #34 (permalink)  
 
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Originally Posted by ACMS View Post
Tankengine:----yes I agree there is a range of STOL Aircraft but they have approved techniques in the POH to do their STOL landings with P charts to suit.

A standard lightie doesn't.
True, but then if you use the POH to find the approach speed for a standard lightie it will probably be 5-10 knots slower than the "instructor approved" speeds these days.
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Old 12th Jul 2017, 10:46
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I see it now. On the subject of short field landings, who'd be silly enough to draw on the knowledge and data derived from the people who land very fast jets very accurately on very short ships?
One important fact to be appreciated is that the airplane ... stalls at the same angle of attack regardless of weight, dynamic pressure, bank angle, etc. Of course, the stall speed of the aircraft will be affected by weight, bank angle, and other factors since the product of dynamic pressure, wing area, and lift coefficient must produce the desired lift. ...
That's why stall warning devices usually sense angle of attack or pressure distribution, not airspeed.

And oddly enough, the definitions of Vs and Vso in the fairly vanilla POH I have in front of me for a fairly vanilla aircraft do not say the speed below which the aircraft stops flying.

Good luck staring at the ASI and using power to manage airspeed to nail that perfect short field landing!

PS: I have been lucky enough to spend some time with an instructor like this one (whom I quoting from the backcountrypilot.org website):
I would suggest that if you want to get comfortable with short strip flying it is good to get comfortable at going slow. I am our company's instructor, and in the first flight with every new company pilot I cover the airspeed indicator, load the plane to gross (about 1100 lbs) and we spend a half hour flying with the stall horn on, clean and dirty, 30 degree banked turns clean and dirty and a descending dirty turns to left and right.

Last edited by Lead Balloon; 12th Jul 2017 at 11:24.
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Old 12th Jul 2017, 11:51
  #36 (permalink)  
 
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Tankengine:---- KISS method to keep it simple for low hour Pilots. 65kts full flap for a PA 28 is what the P charts say at max weight so that's the speed they were taught to fly. Yes it's a little fast by around 10 kts at light weights.

In an ideal world each landing would be checked for weight and conditions and a suitable VREF selected however that gets a little complicated for newbie Pilots.

If you need to land on a short strip in the bush then you should consult the P charts and fly the speed BUT this is not a short field landing.

Anyway....
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Old 12th Jul 2017, 12:33
  #37 (permalink)  
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yes I agree there is a range of STOL Aircraft but they have approved techniques in the POH to do their STOL landings with P charts to suit.

I don't see anything in the certification standards for civil STOL. Can you post some specific POH technique words and a P chart or two to support your contention ? I'm only too happy to learn something new ...

Now, what an operator with a need might choose to do is another story altogether ... then it becomes an interest for the Regulator and the insurer.

Military is a different arena.
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Old 12th Jul 2017, 13:23
  #38 (permalink)  
 
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Originally Posted by Lead Balloon View Post
How would you adjust speed in a glider, Cap'n?
push the stick forward? or back? air brakes?

Last edited by cooperplace; 12th Jul 2017 at 14:08.
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Old 12th Jul 2017, 15:05
  #39 (permalink)  
 
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Originally Posted by cooperplace View Post
push the stick forward? or back? air brakes?
All three will work, of course using the last may well kill you!
An A380 Captain embarassed himself by using the wrong technique a while ago then made it worse by telling everyone unknowingly at briefing!

Last edited by Tankengine; 13th Jul 2017 at 01:03.
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Old 12th Jul 2017, 23:16
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Originally Posted by Tankengine View Post
All three will work, of course using the last may well kill you!
An A380 Captain embaressed himself by using the wrong technique a while ago then made it worse by telling everyone unknowingly at briefing!
of course; I use all 3 as required when I'm in the Grob.
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