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jindoguy(at)gmail.com
Guest

Posted: Wed Jan 23, 2008 4:57 am Post subject: Dead Stick Approaches ( Holes in the sky)

Tom, all, I don't think we're beating a dead horse. The discussion is forcing me to think the problem through and not just regurgitate what I learned in pilot training. What Einstein called a gedunken (sp?), a thought experiment. It's winter, bitterly cold outside here on the plains, the DAR is coming Friday afternoon, there is little left to do other than a few minor tweaks, and this is interesting. 

From a physics of flight standpoint there is no such thing as unaccelerated flight. In straight and level, constant speed flight the acceleration forces are in balance. Lift equals weight and drag equals thrust. For all reasonable purposes, weight, the result of the local gravitational field acting on the mass of the aircraft, is the only constant of the four and its acceleration vector never changes, it is always toward the center of the earth. In turning flight the aircraft's inertia wants to keep it going straight, and gravity keeps accelerating the aircraft downward. Lift must counteract both. Wish though I might, there is no free lunch. You've added a new acceleration force, inertia, to the mix thereby disturbing the equilibrium. You've also changed the acceleration vector of the lift. It no longer directly opposes the gravity vector. The effect of inertia is to make the aircraft seem to weigh more. More weight requires more lift. More weight also means the aircraft's stall speed increases. Lift varies at the square of the speed. Speed must increase to keep whatever margin above stall speed you find acceptably safe. 

Of course, one good test beats a thousand theoretical arguments. All that would be required is a recording accelerometer and a sensitive GPS.



Rick



Do not archive

On Jan 23, 2008 1:19 AM, possums < possums(at)bellsouth.net (possums(at)bellsouth.net)> wrote:

[quote]--> Kolb-List message posted by: possums < possums(at)bellsouth.net (possums(at)bellsouth.net)>



At 12:43 AM 1/23/2008, you wrote:

 	  Quote: 	
		  --> Kolb-List message posted by: The Kuffels < kuffel(at)cyberport.net (kuffel(at)cyberport.net)>



Dana, all,



I'm trying to shut up about this topic since it has been beaten to

death.  Still I'm compelled to comment


	




I should show you guys what you can do with the engine off  & vg's & 

no one watching.

But - I would get in trouble---------I'm legal now after 24 yrs.

Like they say in the song. "Dance like no one is watching".

I've got a one-seater - and an "iPod" tied into my  helmet. = the many List utilities such as List Un/Subscription, w.matronics.com/Navigator?Kolb-List" target="_blank">http://www.matronics.com/Navigator?Kolb-List tp://forums.matronics.com" target="_blank"> =             - List Contribution Web Site ;                          -Matt Dralle, List Admin. =======



[b]

John Hauck

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

Posted: Wed Jan 23, 2008 6:42 am Post subject: Dead Stick Approaches ( Holes in the sky)

Morning Gang:

  

 Got a G Meter and a GPS.

  

 If I can get a flight in between rain showers, I'll  fly over to Wetumpka Airport and shoot some dead stick landings to the  north/south grass strip.

  

 What are you guys looking for?  Maintaining 1G  during a dead stick approach while performing 180 deg turns?

  

 I'll see what I can do.

  

 I need to fly anyhow.  I have a 400 rpm mag  drop on one side.  Talked to Ronnie Smith about it yesterday.  He told  me to double check to insure the throttle lever clevis's are lubed and free,  where they attach to the throttle cables.  Told me this can cause a mag  drop by getting the carbs out of sync/balance.  My first thought was spark  plugs.  I have a set to stick in if the throttle lube does not cure my mag  drop.  Never had this problem before, but there is always a first  time.

  

 Eric Tucker will be at Ronnie's tomorrow.   Rotax classes begin Friday.  Ronnie will coordinate a time for me to fly  down to replace the gears in my 912ULS.  If Eric can fit it in, he will  incorporate my gear change with that portion of the 912 course.

  

 Take care,

  

 john h

 mkIII

 [quote]    Of course, one good test beats a thousand    theoretical arguments. All that would be required is a recording accelerometer    and a sensitive GPS.



Rick



 

[b]

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

jindoguy(at)gmail.com
Guest

Posted: Wed Jan 23, 2008 8:37 am Post subject: Dead Stick Approaches ( Holes in the sky)

John, Could your throttle cables have stretched or changed in such a way that your carbs got out of synch?



Rick



On Jan 23, 2008 8:39 AM, John Hauck < jhauck(at)elmore.rr.com (jhauck(at)elmore.rr.com)> wrote:

[quote]       Morning Gang:

  

 Got a G Meter and a GPS.

  

 If I can get a flight in between rain showers, I'll  fly over to Wetumpka Airport and shoot some dead stick landings to the  north/south grass strip.

  

 What are you guys looking for?  Maintaining 1G  during a dead stick approach while performing 180 deg turns?

  

 I'll see what I can do.

  

 I need to fly anyhow.  I have a 400 rpm mag  drop on one side.  Talked to Ronnie Smith about it yesterday.  He told  me to double check to insure the throttle lever clevis's are lubed and free,  where they attach to the throttle cables.  Told me this can cause a mag  drop by getting the carbs out of sync/balance.  My first thought was spark  plugs.  I have a set to stick in if the throttle lube does not cure my mag  drop.  Never had this problem before, but there is always a first  time.

  

 Eric Tucker will be at Ronnie's tomorrow.   Rotax classes begin Friday.  Ronnie will coordinate a time for me to fly  down to replace the gears in my 912ULS.  If Eric can fit it in, he will  incorporate my gear change with that portion of the 912 course.

  

 Take care,

  

 john h

 mkIII

  	  Quote: 	
		      Of course, one good test beats a thousand    theoretical arguments. All that would be required is a recording accelerometer    and a sensitive GPS.



Rick



 



	


[b]

John Hauck

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

Posted: Wed Jan 23, 2008 8:49 am Post subject: Dead Stick Approaches ( Holes in the sky)

Rick:

  

 I doubt it, but anything is possible when Murphy is  there to help.

  

 I have put over 2500 hours on three 912  engines.  Until this last engine, never synchronized the carbs with  gauges.  This is the first occurrence of a mag drop I have experienced,  unless I had a plug trying to foul.  Then, the problem was solved by some  good hard running of the 912.

  

 john h

 mkIII

 [quote]    

John, Could your throttle cables    have stretched or changed in such a way that your carbs got out of    synch?



Rick

 [b]

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

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Wed Jan 23, 2008 9:48 am Post subject: Dead Stick Approaches ( Holes in the sky)

At 12:43 AM 1/23/2008, The Kuffels wrote:

 	  Quote: 	
		  ...Keep your speed constant, it keeps your total load constant and keeps 

your stall margin constant.  We are talking about 90 or 180 degree turns 

here.  In theory your decent rate will continue to increase at constant 

airspeed in a bank.  In practice the increased vertical component of drag 

slows the increase in decent rate and things remain nicely stable on rollout...


	


If you roll into a bank and AND keep it coordinated (ball in center), then 

you have to either pitch up by pulling back on the stick (thus pulling more 

than 1g), or you have to yaw toward the bottom of the turn, which means 

your nose drops (the plane naturally does this if you don't pull back on 

the stick to keep the nose up).  Thus you'll accelerate down and pick up 

speed, since the drag doesn't increase that much (except as a function of 

speed).  Either way, in a bank at least one of three things MUST 

happen:  You pull more than 1g, or you're flying uncoordinated (slipping), 

or your speed increases.



I do agree with what I presume was your original point, that you avoid an 

accelerated stall by letting the nose drop and the aircraft accelerate... 

though this is probably more effective in a slow draggy airplane like an 

ultralight than a faster, cleaner GA plane.



Later, of course, you have to exceed 1g pulling out of the resultant dive.



-Dana

--

  Televangelists: The Pro Wrestlers of religion.

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Wed Jan 23, 2008 10:09 am Post subject: Dead Stick Approaches ( Holes in the sky)

At 07:55 AM 1/23/2008, Richard Girard wrote:

 	  Quote: 	
		   From a physics of flight standpoint there is no such thing as 

 unaccelerated flight. In straight and level, constant speed flight the 

 acceleration forces are in balance. Lift equals weight and drag equals thrust.


	


You're confusing force and acceleration.  The _forces_ are in balance, and 

thus the _acceleration_ is zero.



 	  Quote: 	
		    In turning flight the aircraft's inertia wants to keep it going 

 straight, and gravity keeps accelerating the aircraft downward. Lift must 

 counteract both. Wish though I might, there is no free lunch. You've 

 added a new acceleration force, inertia, to the mix thereby disturbing 

 the equilibrium. You've also changed the acceleration vector of the lift. 

 It no longer directly opposes the gravity vector.


	


Inertia isn't really a force (although it can sometimes be treated as such 

depending on your frame of reference).



In turning flight at a constant altitude, the lift vector is no longer 

vertical (due to the bank).  Lift must increase so that the vertical 

component of lift is still equal to the force from gravity.  The horizontal 

component of lift is unbalanced, so it causes an _acceleraton_ to the side 

(F=MA), causing the turn.  This acceleration, multiplied by the mass of the 

aircraft, is what you're terming inertia (the plane "wanting" to keep going 

straight).



I realize this is basic, you clearly understand it despite incorrect 

terminology, but in physics (and aerodynamics!) it's important to use exact 

terminology.



To maintain 1g in a banked turn, the aircraft must accelerate downward as a 

result of the reduced vertical component of lift, _and_ accelerate to the 

inside of the turn according to the horizontal component of lift.  The 

result is a steepening spiral dive, which, over the course of a 180° turn, 

may or may not develop to alarming speeds or pitch angles.



-Dana



--

  Televangelists: The Pro Wrestlers of religion.

John Hauck

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

Posted: Wed Jan 23, 2008 12:08 pm Post subject: Dead Stick Approaches ( Holes in the sky)

> At 12:43 AM 1/23/2008, The Kuffels wrote:

 	  Quote: 	
		  >...Keep your speed constant, it keeps your total load constant and keeps 

>your stall margin constant.  We are talking about 90 or 180 degree turns 

>here.  In theory your decent rate will continue to increase at constant 

>airspeed in a bank.  In practice the increased vertical component of drag 

>slows the increase in decent rate and things remain nicely stable on 

>rollout...

Tom K

 > I do agree with what I presume was your original point, that you avoid an

 	  Quote: 	
		   accelerated stall by letting the nose drop and the aircraft accelerate... 

 though this is probably more effective in a slow draggy airplane like an 

 ultralight than a faster, cleaner GA plane.

 Later, of course, you have to exceed 1g pulling out of the resultant dive.

 -Dana

Dana:

You need to get out and fly a little.  It did wonders for me.  The computer 

monitor is no substitute for some good old fashioned aviating.

I landed about 15 minutes ago after practicing gliding to touch down at idle 

power and also dead stick.  While gliding, I also practiced left and right 

turns of 90 and 180 degrees, keeping my airspeed constant (well.........as 

best I could    ).

Results, 1 G all the way to the ground.  Hard to get into an accelerated 

stall at 1 G.  Hard to stall a Kolb, unless you violate the minimum stall 

speed.

john h

mkIII - Still got a mag drop, even though I oiled up the throttle cable 

clevis's at the carb throttle levers.  Next, replace the spark plugs Travis 

sent me yesterday.  I might have gotten some heat sink paste too far down on 

one or more of the plugs when I recently replaced them.

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

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Wed Jan 23, 2008 12:20 pm Post subject: Re: Dead Stick Approaches ( Holes in the sky)

 	  jindoguy(at)gmail.com wrote: 	
		  



 In turning flight the aircraft's inertia wants to keep it going straight, and gravity keeps accelerating the aircraft downward. Lift must counteract both. Wish though I might, there is no free lunch. You've added a new acceleration force, inertia, to the mix thereby disturbing the equilibrium. 

[b] 	




This is what I have been saying all along.  If you turn, you MUST generate more than  1 G load on your wings.  You either load the plane with 1 G either during the turn, or after the turn to arrest the resulting dive, or both.  But, as I said before, you don't get something for nothing.  It takes force to turn a moving airplane, and that force is generated by the wings.



What is happening is that some guys are flying it so smoothly, that they don't realize that they are putting more than 1 G on the wings, but realize it or not, they are...  Its a physical law that no amount of good piloting is going to break.   Most likely they are putting some extra load on the wing, not much, but some during the turn, and again more than 1 G load while pulling out while leveling off, they just don't realize it.



What Tom suggested is good piloting and very good technique, if I was writing about it, I would not say you never put more than 1 G load on the wing, because it is just plain wrong.   Teach your technique, but get the theory correct also when you teach it...  It will be more credible and make for much happier readers     It will also save embarrassment when pilots that are familiar with flight physics read your article.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Wed Jan 23, 2008 12:24 pm Post subject: Re: Dead Stick Approaches ( Holes in the sky)

[quote="Possums"]At 12:43 AM 1/23/2008, you wrote:

 	  Quote: 	
		  



I should show you guys what you can do with the engine off  & vg's & 

no one watching.



. 	




Now you have done it, I gotta see this !!!   Just put the video on YouTube and post the link here  



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

John Hauck

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

Posted: Wed Jan 23, 2008 12:44 pm Post subject: Dead Stick Approaches ( Holes in the sky)

 	  Quote: 	
		   This is what I have been saying all along.  If you turn, you MUST generate 

 more than  1 G load on your wings.  You either load the plane with 1 G 

 either during the turn, or after the turn to arrest the resulting dive, or 

 both.  But, as I said before, you don't get something for nothing.  It 

 takes force to turn a moving airplane, and that force is generated by the 

 wings.



 What is happening is that some guys are flying it so smoothly, that they 

 don't realize that they are putting more than 1 G on the wings, but 

 realize it or not, they are...  Its a physical law that no amount of good 

 piloting is going to break.   Most likely they are putting some extra load 

 on the wing, not much, but some during the turn, and again more than 1 G 

 load while pulling out while leveling off, they just don't realize it.



 What Tom suggested is good piloting and very good technique, if I was 

 writing about it, I would not say you never put more than 1 G load on the 

 wing, because it is just plain wrong.   Teach your technique, but get the 

 theory correct also when you teach it...  It will be more credible and 

 make for much happier readers     It will also save embarrassment when 

 pilots that are familiar with flight physics read your article.



 Mike


	




Mike B:



Read my last post reference gliding and turning pulling 1g.  I just flew it. 

No big deal.  Keep the air speed constant and the turns will remain at 1g. 

Sorry to disagree.  Yes, I have a certified Accelerometer installed in my 

mkIII.   Rate of descent remained constant as long as I kept the air speed 

contant.



I don't think Tom Kuffle has anything to be embarassed about.  Maybe you 

need to do some homework before you tell somebody else they are full of 

crap.  



Take care,



john h

mkIII - Super 1g glider guy!

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

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Wed Jan 23, 2008 3:06 pm Post subject: Dead Stick Approaches ( Holes in the sky)

At 03:05 PM 1/23/2008, John Hauck wrote:

 	  Quote: 	
		  You need to get out and fly a little.  It did wonders for me.  The 

computer monitor is no substitute for some good old fashioned aviating.


	


You're right, I do!  Just too damn cold here, right now.



 	  Quote: 	
		  I landed about 15 minutes ago after practicing gliding to touch down at 

idle power and also dead stick.  While gliding, I also practiced left and 

right turns of 90 and 180 degrees, keeping my airspeed constant 

(well.........as best I could    ).



Results, 1 G all the way to the ground.  Hard to get into an accelerated 

stall at 1 G.  Hard to stall a Kolb, unless you violate the minimum stall 

speed.


	


John, how sensitive is your G meter?  In a 30° banked turn you only pull 

1.15g; 20° only 1.06g.  And how much bank, and were all turns coordinated?



I'll stick with Mike here; no amount of good piloting can break the laws of 

physics.  An object moving along a curved path experiences acceleration in 

the plane of the curve, perpendicular to the direction of motion.  The 

vector sum of that acceleration and the 1g downward pull of gravity is the 

total g's you're pulling, so unless you push the nose down to reduce the 

vertical 1g, that vector sum will be greater than 1.0... and if you push 

the nose down you won't maintain that constant speed.  It is impossible to 

make a coordinated turn at a constant velocity in an airplane while 

maintaining only 1g, unless you have some means to continuously increase 

drag (or decrease thrust) as the airplane pitches down... and even then you 

will see more than 1g pulling out of the resultant dive.  TANSTAAFL (There 

Ain't No Such Thing As A Free Lunch).



I _will_ believe it's possible (in a shallow bank), within the accuracy of 

the instruments installed on most aircraft.



-Dana

--

  It feels great to wake up and not know what day it is, doesn't it?

John Hauck

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

Posted: Wed Jan 23, 2008 3:41 pm Post subject: Dead Stick Approaches ( Holes in the sky)

 	  Quote: 	
		  >Results, 1 G all the way to the ground.  Hard to get into an accelerated

>stall at 1 G.  Hard to stall a Kolb, unless you violate the minimum stall 

>speed.



 John, how sensitive is your G meter?  In a 30° banked turn you only pull 

 1.15g; 20° only 1.06g.  And how much bank, and were all turns coordinated?

 >
	


 	  Quote: 	
		   I _will_ believe it's possible (in a shallow bank), within the accuracy of 

 the instruments installed on most aircraft.



 -Dana


	




Dana:



My accelerometer is as accurate and sensitive enough to get a yellow tag.



Most folks that know me and my flying style will tell you me and Miss P'fer 

don't know what a 20 and 30 degree bank are.  We fly, and have a hell of a 

lot of fun doing it.  I can assure you my banks were well over 45 degrees 

because it takes that and much more to to nice tight 90 and 180 degree turns 

at 60 mph in a mkIII.  If I made the turn and maintained altitude, it pulled 

a g.  If I maintained 60 mph until I touched down, I never pulled more than 

1 g.



I just got back from doing some more maintenance and test flying.  What a 

beautiful day to fly.  Calm air, 48F on the ground and 40F at 3,000.  Makes 

no difference whether you believe me or not.   The mkIII still glides and 

turns at 1g with constant airspeed.  To be honest, I would not have believed 

it entirely either, until I did it this morning.



Guess you'll just have to go out and do this exercise yourself to see what 

the results are.  I'd be glad to demonstrate if you are in the area.



Take care and watch your g meter.



john h

mkIII

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

kuffel(at)cyberport.net
Guest

Posted: Wed Jan 23, 2008 5:43 pm Post subject: Dead Stick Approaches ( Holes in the sky)

Dana,



<< The vector sum of that acceleration and the 1g downward pull 

of gravity is the total g's you're pulling, so unless you push 

the nose down to reduce the vertical 1g, that vector sum will be 

greater than 1.0. >>



But we aren't keeping a vertical 1g.  At constant airspeed and 

level flight we are keeping 1g on the wings.  Now rotate the 

wings.  The 1g load vector rotates with the wing to produce 2 

components.  One horizontal to produce the turning acceleration 

and a correspondingly lower vertical to oppose (partly) earth's 

gravity.  Which is of course why we start descending more rapidly.



The point remains if you maintain a constant airspeed while 

maneuvering to land you will never reduce your stall margin (+/- 

the secondary effect of increasing and decreasing your decent 

rate).  This is most important in the 90 degree turn to final 

where every year pilots try to hasten the turn with rudder.  In 

the 180 reversing turns on a dead stick approaches (remember dead 

stick approaches, this is a thread about dead stick approaches) 

it doesn't matter where you roll out left or right so just use a 

constant shallow bank and constant airspeed.  This is good habit 

building practice for the 90 turn to final where you might want 

to tighten the turn by increasing the bank angle without fear.



Tom Kuffel

Whitefish, MT

Building Original FireStar

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Wed Jan 23, 2008 7:10 pm Post subject: Dead Stick Approaches ( Holes in the sky)

At 08:40 PM 1/23/2008, The Kuffels wrote:

 	  Quote: 	
		  



<< The vector sum of that acceleration and the 1g downward pull of gravity 

is the total g's you're pulling, so unless you push the nose down to 

reduce the vertical 1g, that vector sum will be greater than 1.0. >>



But we aren't keeping a vertical 1g.  At constant airspeed and level 

flight we are keeping 1g on the wings.  Now rotate the wings.  The 1g load 

vector rotates with the wing to produce 2 components.  One horizontal to 

produce the turning acceleration and a correspondingly lower vertical to 

oppose (partly) earth's gravity.  Which is of course why we start 

descending more rapidly.


	


Right, you start accelerating downward if the vertical component is less 

than 1g.



 	  Quote: 	
		  The point remains if you maintain a constant airspeed while maneuvering to 

land you will never reduce your stall margin...


	


That's the part I have a problem with, if you're accelerating downward your 

airspeed won't be constant.  Since you're _accelerating_ downward your 

descent rate will continue to increase, as will your airspeed.  The only 

way to keep the speed from increasing is to slip the plane, which adds a 

whole new set of variables.



A good example is the second half of a wingover (or the last quarter of a 

standard Lazy-.  At the highest point in the wingover, you're banked, 

say, 45°, the ball is centered, pulling 1g or maybe even less, but you are 

accelerating downward since the vertical component of lift is greater than 

the airplane's weight.  But the pullout at the bottom will be greater than 

1g, since the wings then are both supporting the aircraft's weight but also 

providing the force to accelerate the plane upward to slow the increased 

descent rate.



But again, I agree as a matter of good technique:  Let the nose drop in the 

turn, which lets the plane speed up a bit while simultaneously reducing the 

load factor.



Hmmm, just thought of something:  In a pusher like a Kolb the instruments 

(including John Hauck's g-meter) are well forward of the C.G., unlike a 

conventional tractor plane.  A g-meter mounted forward of the aircraft's 

C.G. will show less than the actual g's while the aircraft is pitching 

downward (just as a g-meter mounted on the tail would show a _greater_ 

reading).  Not sure how significant (if at all) that would be, though.



-Dana

--

  The secret of the universe is (at)*^^^ NO CARRIER

John Hauck

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

Posted: Wed Jan 23, 2008 7:29 pm Post subject: Dead Stick Approaches ( Holes in the sky)

> Hmmm, just thought of something:  In a pusher like a Kolb the instruments

 	  Quote: 	
		   (including John Hauck's g-meter) are well forward of the C.G., unlike a 

 conventional tractor plane.  A g-meter mounted forward of the aircraft's 

 C.G. will show less than the actual g's while the aircraft is pitching 

 downward (just as a g-meter mounted on the tail would show a _greater_ 

 reading).  Not sure how significant (if at all) that would be, though.



 -Dana


	




Dana:



When the aircraft is flying at 1g, in a glide, it is not pitching if the 

airspeed is held constant.



I flew the maneuvers many times on two seperate flights today.



Based on the g meter and my own flying experience, I am quite satisfied the 

turns were done without loading the aircraft to more than 1 g.



Guess the only way to convince you is take you for a ride.  



Damn!  The g meter is on the wrong side of the cg.  (scratching my head)



john h

mkIII

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

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Wed Jan 23, 2008 8:18 pm Post subject: Dead Stick Approaches ( Holes in the sky)

---

_________________
do not archive

kuffel(at)cyberport.net
Guest

Posted: Wed Jan 23, 2008 10:48 pm Post subject: Dead Stick Approaches ( Holes in the sky)

Dana,



<< Since you're _accelerating_ downward your descent rate will 

continue to increase, as will your airspeed. >>



Taint so on the second part.  Your decent rate will increase 

slightly until the vertical component of your drag cancels the 

loss of vertical lift (if you turn long enough).  But your 

airspeed is your velocity forward, almost orthogonal to vertical. 

  In non-aerobatic flight it is a simple matter to adjust your 

airspeed and accept the resulting descent rate.



And I say again, your vertical accelerations are a secondary 

effect.  Even a 500 feet/min descent is less than 1 percent of 

your forward velocity at 60 mph.  And a change in descent rate 

from 250 to 500 ft/min is a change in your vertical velocity of 

less than 3 mph.  This is well within the ability of any pilot to 

compensate as he maintains constant *forward* airspeed.



High-g pullout examples don't apply here because they involve 

large changes in airspeed, power or vertical speed.



Go try it for yourself.  In a simulated turn to final, holding 

constant airspeed results in a 1g maneuver no matter what bank 

angle (within reason, say 60 degrees).



Tom Kuffel

Whitefish, MT

Building Original FireStar

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Thu Jan 24, 2008 4:21 am Post subject: Dead Stick Approaches ( Holes in the sky)

At 10:26 PM 1/23/2008, John Hauck wrote:



 	  Quote: 	
		  When the aircraft is flying at 1g, in a glide, it is not pitching if the 

airspeed is held constant.


	


It is if it's in a banked turn.  (It pitches relative to its own lateral 

axis, not relative to the horizon).



-Dana

--

  Starve a feeding bureaucrat...vote Libertarian.

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Thu Jan 24, 2008 4:21 am Post subject: Dead Stick Approaches ( Holes in the sky)

At 01:45 AM 1/24/2008, The Kuffels wrote:



 	  Quote: 	
		  << Since you're _accelerating_ downward your descent rate will continue to 

increase, as will your airspeed. >>



Taint so on the second part.  Your decent rate will increase slightly 

until the vertical component of your drag cancels the loss of vertical 

lift (if you turn long enough)...


	


What causes this additional vertical component of drag?



-Dana



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Rex Rodebush

Joined: 10 Jan 2006
Posts: 209
Location: Branson West area, Missouri

Posted: Thu Jan 24, 2008 5:35 am Post subject: Re: Dead Stick Approaches ( Holes in the sky)

It's been awhile but I'll add my 2 cents worth.



Anytime you change directions you produce acceleration.  It may not be much or enough to feel or register but it's there.  Whether it's on a merry-go-round or on a bike going around a corner.  If you're sitting in a centrifuge and are going around at 1 rpm you will still have slightly over 1 g on you as it is a function of radius and rpm squared.  Even though your speed is constant your direction vector is changing.



Rex Rodebush

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