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W & B, cruising, stalling and landing
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aslsa.rng(at)gmail.com
Guest

Posted: Thu Aug 06, 2009 4:49 am Post subject: W & B, cruising, stalling and landing

I figured I'd just roll all the topics up into a single heading. Some interesting claims are being thrown around and all the RE:'s make it too hard to comment otherwise.



"you will never full stall land that airplane....at least not without  slamming the mains on the ground"

  



Chris, Sure you can. All you have to do is hold it off and get it slow enough. Any aircraft can be slowed enough so that it's vertical and horizontal velocity vectors reach the critical stall AOA. When you practice approach stalls that's exactly what you're doing. The aircraft isn't at some high angle relative to the horizon, it's nearly flat, but its vertical velocity becomes such that the critical stall angle is reached. 

  The assumption in this statement is that the speed will be such that the angle increases to the point that the tail wheel hits first, the wing stalls and whammo.

 



"When I position the aircraft at 9 deg. for W & B calculations.....surely this isn't level flight attitude"

 



Depends on what speed the aircraft is travelling. Remember level flight is about having a balance between lift and weight. As long as they're balanced you maintain altitude. If the balance changes you either climb or sink. 

 You can run the numbers for dynamic pressure ( rho*V squared / 2 ) and multiply that times the lift coefficient (which is calculated at angle of attack) and the wing area to get lift in lbs. Conversely you can run the numbers to find at what speed you'll have enough lift for level flight or at what lift coefficient (angle of attack dependent, remember) is needed for a given speed.

 



So, you plug in all the numbers based upon the data for the NACA 66 airfoil (my pick as it is very close to the Kolb airfoil (see Handbook of Airfoil Sections for Light Aircraft by M.S. Rice)), and at 60 miles per hour at a lift coefficient of .95 (AOA 9 degrees) you find the wing of a Mk III producing about 750 lb. of lift. 

 Say, isn't that about what a Mk III with a 190 lb. pilot and full fuel (60 lb.) weighs?



 

Bob, yep that 9 degrees is about cruise AOA for a Mk III.



 

Rick

Addendum, I didn't just pick the numbers out of thin air, pardon the pun. Remember the original Mk III was powered by a 503 Rotax and that 60 mph cruise is about right. John H, you flew that aircraft a bunch, didn't you? I've always assumed that's you in the factory video. Is that a good TLAR cruise number?

 





 



 

  [quote][b]

slyck(at)frontiernet.net
Guest

Posted: Thu Aug 06, 2009 5:11 am Post subject: W & B, cruising, stalling and landing

On 6, Aug 2009, at 8:44 AM, Richard Girard wrote:

 	  Quote: 	
		  So, you plug in all the numbers based upon the data for the NACA 66 airfoil (my pick as it is very close to the Kolb airfoil (see Handbook of Airfoil Sections for Light Aircraft by M.S. Rice)), and at 60 miles per hour at a lift coefficient of .95 (AOA 9 degrees) you find the wing of a Mk III producing about 750 lb. of lift. 

Say, isn't that about what a Mk III with a 190 lb. pilot and full fuel (60 lb.) weighs?

	




My tubby scow weighs over 600# empty (been a while since I weighed it and there is MORE crap on it now)

The wings are clipped a foot on each end and by some magic (wires maybe?) it will fly at 50 mph and maybe less.

BB, 170 lbs + average 40 lbs fuel

 [quote][b]

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Thu Aug 06, 2009 5:46 am Post subject: Re: W & B, cruising, stalling and landing

 	  aslsa.rng(at)gmail.com wrote: 	
		  I figured I'd just roll all the topics up into a single heading. Some interesting claims are being thrown around and all the RE:'s make it too hard to comment otherwise.



"you will never full stall land that airplane....at least not without ï¿½slamming the mains on the ground"

  



Chris, Sure you can. All you have to do is hold it off and get it slow enough. Any aircraft can be slowed enough so that it's vertical and horizontal velocity vectors reach the critical stall AOA. When you practice approach stalls that's exactly what you're doing. The aircraft isn't at some high angle relative to the horizon, it's nearly flat, but its vertical velocity becomes such that the critical stall angle is reached.ï¿½

	




Don't understand how this follows. 



Stall is determined by angle of attack, NOT airspeed. 



If the AOA remains below the critical AOA with respect to the relative wind, the wing will NOT be stalled. The airspeed may drop below that needed to insure enough lift is generated to overcome gravity, but that has nothing to do with _stall_.



When you practice approach stalls you're toying with the maximum amount of lift that the wing can generate at a given airspeed. What you eventually discover is that the max lift that can be generated is not enough at too low of an airspeed and you continue to increase AOA to try to compensate - you exceed the critical AOA and you stall.



Can't remember when stall became determined by airspeed. I must have been out to lunch when that law of physics was changed......



LS

_________________
LS
Titan II SS

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Aug 06, 2009 7:14 am Post subject: W & B, cruising, stalling and landing

Richard:

  

 Yes, I flew the test time off the original MKIII  powered with a 582.

  

 I don't remember what the cruise speed, at 5800  rpm, was for "Fat Albert".  Been too long ago.

  

 Homer's designs, after the Ultrastar, emphasized  safety for low time pilots.  Therefore, the aircraft sat nearly level on  the ground with most of the weight on the mains.  This did several  things:

  

 1-Made those airplanes very easy to handle  taildraggers.

  

 2-Required pilots to land and takeoff at higher  airspeeds to reduce the chance of inadvertent stall.  That is why the  tailwheel hits first when one attempts to do a full stall landing.  That is  why all my Kolbs, except the Ultrastar, had longer than standard gear legs to  put them into a good 3 point stance.

  

 3-Required the wings be rigged with more angle of  attack so we could take off and land in a nearly level attitude, and to prevent  the tail from sagging to the extreme when doing slow flight.  It also slows  the cruise speed because of additional drag of pulling the tailboom through the  air sideways.  The Sling Shot will really sag in the tail when slowed down  because is has a lot less incidence than the MKIII and FS.

  

 john h

 mkIII

  

  

  

  

  

  

 [quote]    

   Addendum,    I didn't just pick the numbers out of thin air, pardon the pun. Remember the    original Mk III was powered by a 503 Rotax and that 60 mph cruise is about    right. John H, you flew that aircraft a bunch, didn't you? I've always assumed    that's you in the factory video. Is that a good TLAR cruise    number?

    

[b]

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

by0ung(at)brigham.net
Guest

Posted: Thu Aug 06, 2009 7:19 am Post subject: W & B, cruising, stalling and landing

Can't remember when stall became determined by airspeed. I must have been out to lunch when that law of physics was changed......  

   

LS  

 	  Quote: 	
		  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>   

   
	


Well,,,,,, in a 1 g maneuver the critical angle of attack  will be very predictable when using the asi.    Change the g loading of the wing and the  numbers will start to move around a bit.  And in high g loading it will move more than a bit,,, lets say a bunch.  

   

Boyd   

       [quote][b]

aslsa.rng(at)gmail.com
Guest

Posted: Thu Aug 06, 2009 7:39 am Post subject: W & B, cruising, stalling and landing

Lucien, Look in any aircraft POH, do they tell you stall angle or stall speed? It's apples and pears, but they're still fruit.Â How many GA aircraft have AOA indicators? They ALL have airspeed indicators.

 Yes, stalls happen when an airfoil reaches about 13 to 16 degrees angle of attack, but in actual flight they reach those angles at certain corresponding airspeeds. We fly approach speeds, rotation speeds, cruise speeds, and on and on.Â 

Rick

On Thu, Aug 6, 2009 at 8:46 AM, lucien <lstavenhagen(at)hotmail.com (lstavenhagen(at)hotmail.com)> wrote:

[quote] --> Kolb-List message posted by: "lucien" <lstavenhagen(at)hotmail.com (lstavenhagen(at)hotmail.com)>

 aslsa.rng(at)gmail.com wrote:

 > I figured I'd just roll all the topics up into a single heading. Some interesting claims are being thrown around and all the RE:'s make it too hard to comment otherwise.

 >

 > "you will never full stall land that airplane....at least not without ï¿½slamming the mains on the ground"

 >

 >

 > Chris, Sure you can. All you have to do is hold it off and get it slow enough. Any aircraft can be slowed enough so that it's vertical and horizontal velocity vectors reach the critical stall AOA. When you practice approach stalls that's exactly what you're doing. The aircraft isn't at some high angle relative to the horizon, it's nearly flat, but its vertical velocity becomes such that the critical stall angle is reached.ï¿½

  >

 Don't understand how this follows.

 Stall is determined by angle of attack, NOT airspeed.

 If the AOA remains above the critical AOA, the wing will NOT stall. The airspeed may drop below that needed to insure enough lift is generated to overcome gravity, but that has nothing to do with _stall_.

 When you practice approach stalls you're toying with the maximum amount of lift that the wing can generate at a given airspeed. What you eventually discover is that the max lift that can be generated is not enough at too low of an airspeed and you continue to increase AOA to compensate - you exceed the critical AOA and you stall.

 Can't remember when stall became determined by airspeed. I must have been out to lunch when that law of physics was changed......

 LS

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 LS

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 http://forums.matronics.com/viewtopic.php?p=256328#256328

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lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Thu Aug 06, 2009 12:54 pm Post subject: Re: W & B, cruising, stalling and landing

 	  aslsa.rng(at)gmail.com wrote: 	
		  Lucien, Look in any aircraft POH, do they tell you stall angle or stall speed? It's apples and pears, but they're still fruit.Â How many GA aircraft have AOA indicators? They ALL have airspeed indicators.

 Yes, stalls happen when an airfoil reaches about 13 to 16 degrees angle of attack, but in actual flight they reach those angles at certain corresponding airspeeds. We fly approach speeds, rotation speeds, cruise speeds, and on and on.Â 

 



Rick

	




That doesn't change the fact that stall is not determined by airspeed, but only AOA of the main wing.



The stall airspeeds listed in POH's are those that happen under steady state conditions of flight with a particular loading, where there's a reasonably reliable correspondence between airspeed and where the critical AOA is reached or exceeded to maintain that steady state condition.



You'll notice all this with stall airspeed changes when you add weight to the plane, or are in a mode of flight where you're pulling more G's, etc.

but the AOA at which the wing stalls doesn't change. That's the key to avoiding (or achieving) a stall, not airspeed.



Sorry guys, but I don't think any of this has ever changed (or ever will )......



LS

_________________
LS
Titan II SS

aslsa.rng(at)gmail.com
Guest

Posted: Thu Aug 06, 2009 3:17 pm Post subject: W & B, cruising, stalling and landing

No argument. It's a great text book truth that gets translated into practical use by making the translation to a speed to fly.The point was that stall angle is related to the relative wind, not the ground. You can slow up an aircraft, even the Kolb with it's Dorf gear legs, and get a full stall landing in a level attitude in relation to the ground, you don't have to bang the tailwheel down followed by a great impact on the mains.

Rick

On Thu, Aug 6, 2009 at 3:54 PM, lucien <lstavenhagen(at)hotmail.com (lstavenhagen(at)hotmail.com)> wrote:

[quote] --> Kolb-List message posted by: "lucien" <lstavenhagen(at)hotmail.com (lstavenhagen(at)hotmail.com)>

 aslsa.rng(at)gmail.com wrote:

 > Lucien, Look in any aircraft POH, do they tell you stall angle or stall speed? It's apples and pears, but they're still fruit. How many GA aircraft have AOA indicators? They ALL have airspeed indicators.

  >  Yes, stalls happen when an airfoil reaches about 13 to 16 degrees angle of attack, but in actual flight they reach those angles at certain corresponding airspeeds. We fly approach speeds, rotation speeds, cruise speeds, and on and on. 

  >

 >

 > Rick

 >

 That doesn't change the fact that stall is not determined by airspeed, but only AOA of the main wing.

 The stall airspeeds listed in POH's are those that happen under steady state conditions of flight with a particular loading, where there's a reasonably reliable correspondence between airspeed and where the critical AOA is reached or exceeded to maintain that steady state condition.

 You'll notice all this with stall airspeed changes when you add weight to the plane, or are in a mode of flight where you're pulling more G's, etc.

 but the AOA at which the wing stalls doesn't change. That's the key to avoiding (or achieving) a stall, not airspeed.

 Sorry guys, but I don't think any of this has ever changed (or ever will )......

 LS

 --------

 LS

 Titan II SS

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 http://forums.matronics.com/viewtopic.php?p=256407#256407

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lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Thu Aug 06, 2009 5:42 pm Post subject: Re: W & B, cruising, stalling and landing

 	  aslsa.rng(at)gmail.com wrote: 	
		  No argument. It's a great text book truth that gets translated into practical use by making the translation to a speed to fly.The point was that stall angle is related to the relative wind, not the ground. You can slow up an aircraft, even the Kolb with it's Dorf gear legs, and get a full stall landing in a level attitude in relation to the ground, you don't have to bang the tailwheel down followed by a great impact on the mains.

 



Rick

	




FWIW, It has always surprised me how much argument I get against this, an amazing number of folks insist that airspeed is really what determines stall and I mean they push back on me _hard_ when I tell them it's not. 



Most probably don't see why they can fly their planes just fine with completely inop ASI's or avoid stalls in steep turns etc. where ASI's are useless. I usually tell them it's because they already have the skill of AOA control in their skill sets, but I get loads of pushback here too for mysterious reasons, guys simply just don't believe me. they still think it's airspeed somehow.



As for full stalls in the Kolb, I was never able to do very good full stall landings in my FSII, but I could get really close in calm conditions. I always seemed to run out of up elevator before I could achieve a stall in a 3-point attitude. But I did achieve it a couple of times.



LS

_________________
LS
Titan II SS

slyck(at)frontiernet.net
Guest

Posted: Thu Aug 06, 2009 6:10 pm Post subject: W & B, cruising, stalling and landing

Probably a good 1/3 of my "landings are plunkers.  The grass is long  

and cushiony  and since no one is watching my feelings

remain undamaged.  The Kolb doesn't mind either.

That business of doing stalls during your first flights in a newborn  

fleugenkraft seems dumb to me, as is

the practice in the usual bi-enema.  The usual, pull the power, try  

to hold altitude until it does some kind of shit.

Well DUH!  Sho dat baby will eventually run out of steam and go  

downhill.  By that time you would have to be an idiot to

not feel the eventuality.   In the real world where do stall  

accidents happen?  Cranking it around your buddy's house

in a steep bank, especially if you have a big fat guy along for the  

ride.

How many pilots have stalled in WITH the engine running, on a normal  

final?  Sober , that is.   None that I know of.

Straight and level?  Even a more rare event.

BTW, I agree with the guy who doesn't bother with the ASI on short  

final.  I have had my share of engine outs, sometimes over less than

perfect terrain.  Was I looking at that little round gauge?  Nay.   

I'm trying to concentrate on conservation of energy or trying to  

bleed off excess.

One sure does get focussed.  Better than a root canal.

BB

On 6, Aug 2009, at 9:42 PM, lucien wrote:

 	  Quote: 	

 aslsa.rng(at)gmail.com wrote:

> No argument. It's a great text book truth that gets translated  

> into practical use by making the translation to a speed to fly.The  

> point was that stall angle is related to the relative wind, not  

> the ground. You can slow up an aircraft, even the Kolb with it's  

> Dorf gear legs, and get a full stall landing in a level attitude  

> in relation to the ground, you don't have to bang the tailwheel  

> down followed by a great impact on the mains.

> Rick

>

 FWIW, It has always surprised me how much argument I get against  

 this, an amazing number of folks insist that airspeed is really  

 what determines stall and I mean they push back on me _hard_ when I  

 tell them it's not.

 Most probably don't see why they can fly their planes just fine  

 with completely inop ASI's or avoid stalls in steep turns etc.  

 where ASI's are useless. It's because they already have the skill  

 of AOA control in their skill sets, but I get loads of pushback  

 when I say this too for mysterious reasons, guys simply just don't  

 believe me.

 As for full stalls in the Kolb, I was never able to do very good  

 full stall landings in my FSII, but I could get really close in  

 calm conditions. I always seemed to run out of up elevator before I  

 could achieve a stall in a 3-point attitude. But I did achieve it a  

 couple of times.

 LS

 --------

 LS

 Titan II SS

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p 56446#256446

Possums

Joined: 03 Nov 2007
Posts: 247

Posted: Thu Aug 06, 2009 7:09 pm Post subject: W & B, cruising, stalling and landing

At 10:04 PM 8/6/2009, you wrote:

 	  Quote: 	
		  



How many pilots have stalled in WITH the engine running, on a normal

final?  Sober , that is.   None that I know of.


	




Oh .....so now we are qualifying it to "sober".

_________________
Possum

Possums

Joined: 03 Nov 2007
Posts: 247

Posted: Thu Aug 06, 2009 7:10 pm Post subject: W & B, cruising, stalling and landing

At 09:42 PM 8/6/2009, you wrote:

 	  Quote: 	
		  get loads of pushback when I say this too for mysterious reasons, 

guys simply just don't believe me.



As for full stalls in the Kolb, I was never able to do very good 

full stall landings in my FSII, but I could get really close in calm 

conditions. I always seemed to run out of up elevator before I could 

achieve a stall in a 3-point attitude. But I did achieve it a couple of times.



LS


	




Put those little plastic VGs in font of your elevator (on the bottom 

of your horizontal stab) and you can

fly down the runway with just you tail wheel touching the ground. You 

don't even have to let your

mains touch the ground if you are showing off. Better have your feet 

on the rudder peddles if your

springs are tight.

_________________
Possum

pj.ladd(at)btinternet.com
Guest

Posted: Fri Aug 07, 2009 1:39 am Post subject: W & B, cruising, stalling and landing

I agree with the guy who doesn't bother with the ASI on short  final.>>



I cannot tell a lie Robert. It was I.  I assumed everyone did it l;ike that.



BTW. I thought the perfect landing was arriving on the ground at the moment 

the plane stopped flying. To me that means arriving at ground level at the 

moment of stall. Then you keep the likelihood of a bounce back into the air 

to a minimum. Given a reasonable surface of course. What is the point of 

doing wheelies which by definition mean that you are still in flying 

position and travelling faster than necessary. You just take more runway or 

have to use the brakes harder to disipate the speed. Ground handling is 

always more fraught than flying..

I am talking about light aircraft of course.



Cheers



Pat

pj.ladd(at)btinternet.com
Guest

Posted: Fri Aug 07, 2009 2:12 am Post subject: W & B, cruising, stalling and landing

but in actual flight they reach those angles at certain corresponding 

airspeeds.>>



Hi Rick,



Not true. Your wing in level flight supports a certain weight . Increase 

that weight and the wing will NOT support it. In other words it stalls. How 

can you do this? Easy! Alter your flight path markedly, this will increase 

the `g` force and the plane will in effect weigh more.



Its all about what a sailor would call `apparent wind` As a yacht increases 

its speed  the direction the wind is coming from moves towards the bow. This 

enables a boat to `point higher`,i.e to decrease the angle of attack. It is 

the same with a planes wing . Go fast and the AOA moves forward, go slowly 

and the AOA moves back. If you increase the weight of the a/c (pull `g`) the 

wing will `mush` through the airand the AOA will move backwards `WHATEVER 

THE AIRSPEED`



I am sure thats clear as mud but think about it.



Cheers



Pat

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Fri Aug 07, 2009 4:16 am Post subject: Re: W & B, cruising, stalling and landing

 	  pj.ladd(at)btinternet.com wrote: 	
		  but in actual flight they reach those angles at certain corresponding 

airspeeds.>>



Hi Rick,



Not true. Your wing in level flight supports a certain weight . Increase 

that weight and the wing will NOT support it. In other words it stalls. How 

can you do this? Easy! Alter your flight path markedly, this will increase 

the `g` force and the plane will in effect weigh more.



Its all about what a sailor would call `apparent wind` As a yacht increases 

its speed  the direction the wind is coming from moves towards the bow. This 

enables a boat to `point higher`,i.e to decrease the angle of attack. It is 

the same with a planes wing . Go fast and the AOA moves forward, go slowly 

and the AOA moves back. If you increase the weight of the a/c (pull `g`) the 

wing will `mush` through the airand the AOA will move backwards `WHATEVER 

THE AIRSPEED`



I am sure thats clear as mud but think about it.



Cheers



Pat 	




Well, no.

This is just a variation of the basic misunderstanding that stall is controlled by airspeed.



There's nothing about airspeed that changes AOA with respect to the relative wind. It can be going by the wing section at 10mph, 1mph, 1000mph, X mph - that doesn't change the AOA. Only a change in the angle of the wing, and/or in the _direction_ of the relative wind will affect this.



Putting it another way, there's nothing in principle that means the AOA of the wing has to reduce when airspeed is increased. That's just a necessary adjustment for maintaining steady-state flight (lift counteracting gravity) when airspeed increases.



Rick is right and this was my original point also - the only time there's a reliable relationship between airspeed and stall is when maintaining steady-state flight (i.e. lift counters gravity or g force). By extension that means AOA also....



LS

_________________
LS
Titan II SS

slyck(at)frontiernet.net
Guest

Posted: Fri Aug 07, 2009 6:17 am Post subject: W & B, cruising, stalling and landing

On a pretty summer evening when the big FEDEX cargo blimp comes  

loitering in slo motion while

descending to ROC over my place,  I still wonder what keeps all those  

parcels up in the clear calm air.



I still think it's magic,   or wires.

BB



On 7, Aug 2009, at 8:16 AM, lucien wrote:



 	  Quote: 	
		   

 pj.ladd(at)btinternet.com wrote:

> but in actual flight they reach those angles at certain corresponding

> airspeeds.>>

>

> Hi Rick,

>

> Not true. Your wing in level flight supports a certain weight .  

> Increase

> that weight and the wing will NOT support it. In other words it  

> stalls. How

> can you do this? Easy! Alter your flight path markedly, this will  

> increase

> the `g` force and the plane will in effect weigh more.

>

> Its all about what a sailor would call `apparent wind` As a yacht  

> increases

> its speed  the direction the wind is coming from moves towards the  

> bow. This

> enables a boat to `point higher`,i.e to decrease the angle of  

> attack. It is

> the same with a planes wing . Go fast and the AOA moves forward,  

> go slowly

> and the AOA moves back. If you increase the weight of the a/c  

> (pull `g`) the

> wing will `mush` through the airand the AOA will move backwards  

> `WHATEVER

> THE AIRSPEED`

>

> I am sure thats clear as mud but think about it.

>

> Cheers

>

> Pat

 Well, no.

 This is just a variation of the basic misunderstanding that stall  

 is controlled by airspeed.



 There's nothing about airspeed that changes AOA with respect to the  

 relative wind. It can be going by the wing section at 10mph, 1mph,  

 1000mph, X mph - that doesn't change the AOA. Only a change in the  

 angle of the wing, and/or in the _direction_ of the relative wind  

 will affect this.



 Rick is right and this was my original point also - the only time  

 there's a reliable relationship between airspeed and stall is when  

 maintaining steady-state flight (i.e. lift = gravity or g force).  

 By extension that means AOA also....



 LS



 --------

 LS

 Titan II SS





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 56477#256477

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Aug 07, 2009 6:49 am Post subject: W & B, cruising, stalling and landing

 	  Quote: 	
		   On a pretty summer evening when the big FEDEX cargo blimp comes

 loitering in slo motion while

 descending to ROC over my place,  I still wonder what keeps all those 

 parcels up in the clear calm air.



 I still think it's magic,   or wires.

 BB


	




Bob B:



It is magic!



I feel it everytime my wheels break ground.  Especially when I haven't flown 

in a while.



Used to get similar feelings sitting at a 3 foot hover.  Absolutely magic. 

Cheating gravity.



To be able to fly, in a contraption I built in my basement, is certainly a 

work of magic, no matter what angle of attack or airspeed.



john h - Doing chores instead of doing aviation.

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

planecrazzzy
Guest

Posted: Fri Aug 07, 2009 3:33 pm Post subject: Re: W & B, cruising, stalling and landing

I agree... Magic...



I named my plane "Miss Lucky Stars"



Every time I'm flying... I'm thanking my Lucky Stars ...



                                 Gotta Fly...

                                                 Mike & "Jaz" the Flying dog

.

.

.

 	  Quote: 	
		  



Bob B:



It is magic!



I feel it everytime my wheels break ground.  Especially when I haven't flown 

in a while.



Used to get similar feelings sitting at a 3 foot hover.  Absolutely magic. 

Cheating gravity.



To be able to fly, in a contraption I built in my basement, is certainly a 

work of magic, no matter what angle of attack or airspeed.



john h - Doing chores instead of doing aviation.

mkIII

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lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Fri Aug 07, 2009 5:10 pm Post subject: Re: W & B, cruising, stalling and landing

 	  planecrazzzy wrote: 	
		  I agree... Magic...



	




Nah, it's not lift or anything like that at all. It's gobs and gobs of cash...



LS

_________________
LS
Titan II SS

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Fri Aug 07, 2009 6:22 pm Post subject: Re: W & B, cruising, stalling and landing

 	  aslsa.rng(at)gmail.com wrote: 	
		  



"you will never full stall land that airplane....at least not without ï¿½slamming the mains on the ground"

  



Chris, Sure you can. All you have to do is hold it off and get it slow enough. Any aircraft can be slowed enough so that it's vertical and horizontal velocity vectors reach the critical stall AOA. When you practice approach stalls that's exactly what you're doing. The aircraft isn't at some high angle relative to the horizon, it's nearly flat, but its vertical velocity becomes such that the critical stall angle is reached.ï¿½

  The assumption in this statement is that the speed will be such that the angle increases to the point that the tail wheel hits first, the wing stalls and whammo.

 



	




Actually, the statement is pretty much correct, your statement at the very last of this quote makes a bad assumption that is just not true.  On my Kolb, there is how it works....



As the speed decreases over the runway, the tailwheel will eventually hit the ground long before the wing stalls... When the tail wheel hits the ground, the tail is forced up slightly, the angle of attack of the wing decreases, there is less lift, the body of the airplane comes down, reducing the angle of attack of the wing even more resulting in even less lift and its going to land, all the pulling back on the stick in the world will not keep the plane from forcibly landing at this point even though the wing is still flying.  Once the tailwheel hits the ground, the plane is coming down even without ever stalling the wing.



It may be possible to full stall land my Kolb, but the angle of attack would be so high, the mains would be much to far off the ground to keep the tailwheel from touching before the airplane stalled, possibly bending the gear.  Bottom line is, there is really no way to full stall land my Kolb MK III Xtra without slamming it on the ground hard.



Mike

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Kolb MK-III Xtra, 912-S

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