Does Driver Weight Effect Dyno Output?
08-09-2009, 07:54 PM
#77
Chronic Tool Dropper
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Be glad you don't... There's always good knowledge and good experience to wish for. No need to long for bad.
Mike/Mark, there's a forum on Rennlist called "off topic" that's perfect for discusions that have strayed completely frm the original thread, and/or have absolutely nothing to do with a theme covered by one of the other car-related forums here. Give it a thought.
Mike/Mark, there's a forum on Rennlist called "off topic" that's perfect for discusions that have strayed completely frm the original thread, and/or have absolutely nothing to do with a theme covered by one of the other car-related forums here. Give it a thought.
08-09-2009, 08:31 PM
#80
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Thank you! 
In fact to this off topic discussion, the reason that some of the airbus are falling out of the sky, is the very reason that danlerb might have seen "0" air speed.
the pitot tubes are pretty accurate, to a point.
Was he "flying" with 0 indicated air speed? no. this is because, my definition of flying is when lift equals the force of gravity. The prop can not provide enough lift over the wing with a cessna to keep it floating at 0 air speed over the wing tips. What kind of cessna were we talking about? 172, 182? If flown a few of these and done lazy 8s and where at the top, you feel weight less, and indicated goes toward 0, just as you turn and kick the tail around to gain speed in the other direction. . My dad of about 50,000 hours, and air force experience flying fighters would do cool power on, low air speed manuvers up high to show the control of the rudder, vs the alerons at near stall conditions. We had planes in the family since I can remember.
0 indicated is a measurement of air flow over the wing. if you dont have air flow over the wing, you are not flying, you are falling , regardless of the air mass you are flying/falling in. relative to the ground is different as any one with any flying experience can tell you, a stiff enough headwind, can provide powered flight, but no ground speed. (true air speed).
In fact to this off topic discussion, the reason that some of the airbus are falling out of the sky, is the very reason that danlerb might have seen "0" air speed.
the pitot tubes are pretty accurate, to a point.
Was he "flying" with 0 indicated air speed? no. this is because, my definition of flying is when lift equals the force of gravity. The prop can not provide enough lift over the wing with a cessna to keep it floating at 0 air speed over the wing tips.
What kind of cessna were we talking about? 172, 182? If flown a few of these and done lazy 8s and where at the top, you feel weight less, and indicated goes toward 0, just as you turn and kick the tail around to gain speed in the other direction. . My dad of about 50,000 hours, and air force experience flying fighters would do cool power on, low air speed manuvers up high to show the control of the rudder, vs the alerons at near stall conditions. We had planes in the family since I can remember.0 indicated is a measurement of air flow over the wing. if you dont have air flow over the wing, you are not flying, you are falling , regardless of the air mass you are flying/falling in. relative to the ground is different as any one with any flying experience can tell you, a stiff enough headwind, can provide powered flight, but no ground speed. (true air speed).
Whether Mark K. is or is not a pilot is irrelevant if what he posts is true and factual. In this case his comments are.
An anecdotal experience. Flying north from Ft Carson bombing range (Colo Springs). Encountered severe downdraft in our O-2 (military version of the Cessna Skymaster). Under full power we we still losing altitude at 200 ft/sec. Basically we were flying backwards in terms of ground position but in terms of airspeed we were screaming. Everything relative to aircraft is specific to speed of air over the wings.
BTW - we then encountered heavy hail, severe turbulance and ended up puking inside our flight suits instead of in the cabin or on the instruments. We landed at Buckley ANG base blind and damn near unable to read instruments. Both the command pilot and I purposely went to the O-Club and drank until everything seemed like a blur.
Having enjoyed two commercial airline "mishaps, one military hard dead stick landing and another private aircraft power loss hard bump landing, I know a little about airspeed and what it feels like when things go horribly wrong. Kibbort is dead on in his comments.
FWIW I am not a pilot, but I have spent a ton of hours as aircrew right seat / GIB guy in back on many aircraft types. Still get into the cockpits of aircraft that few have ever seen. I am not expert but knowledgable about basic concepts of flight.
An anecdotal experience. Flying north from Ft Carson bombing range (Colo Springs). Encountered severe downdraft in our O-2 (military version of the Cessna Skymaster). Under full power we we still losing altitude at 200 ft/sec. Basically we were flying backwards in terms of ground position but in terms of airspeed we were screaming. Everything relative to aircraft is specific to speed of air over the wings.
BTW - we then encountered heavy hail, severe turbulance and ended up puking inside our flight suits instead of in the cabin or on the instruments. We landed at Buckley ANG base blind and damn near unable to read instruments. Both the command pilot and I purposely went to the O-Club and drank until everything seemed like a blur.
Having enjoyed two commercial airline "mishaps, one military hard dead stick landing and another private aircraft power loss hard bump landing, I know a little about airspeed and what it feels like when things go horribly wrong. Kibbort is dead on in his comments.
FWIW I am not a pilot, but I have spent a ton of hours as aircrew right seat / GIB guy in back on many aircraft types. Still get into the cockpits of aircraft that few have ever seen. I am not expert but knowledgable about basic concepts of flight.
Last edited by mark kibort; 08-09-2009 at 09:01 PM.
08-09-2009, 08:45 PM
#81
Rennlist Member
For movement relative to the ground, no air speed, all you could have done is porpoise into a hammer head stall where you would be at 0 airspeed and ground speed for a brief second in still air.
In a nut shell, you have NO idea what the true wind component was at the time this happened. reletive wind varies in as little as 50-100ft increments. You could have a slight headwind of more than 10-15knots and at full power, flaps, and attitude, you could have stood still reletive to the ground for a brief period of time. At 0 air speed indicated, the wings would not be flying, so the plane is not flying.
you said you dont need charts and diagrams to show this, so just give me some better explaination of what you think was happening
mk
In a nut shell, you have NO idea what the true wind component was at the time this happened. reletive wind varies in as little as 50-100ft increments. You could have a slight headwind of more than 10-15knots and at full power, flaps, and attitude, you could have stood still reletive to the ground for a brief period of time. At 0 air speed indicated, the wings would not be flying, so the plane is not flying.
you said you dont need charts and diagrams to show this, so just give me some better explaination of what you think was happening
mk
Flying is what happens when you aren't on the ground, the details aren't that important, and I've told you what I can explain without a chalkboard and toy airplanes. The fact that I did stay off the ground was a marvel to me at the time, but none the less a fact.
1. A wing needs differential pressure, air flowing over it is the conventional way that it happens.
2. I suppose, orientation of the plane was not static.
3. I don't recall any significant wind, but other effects may have been occurring, like warm air rising off the runway.
4. I still don't recall any significant wind.
5. Disagree, off the ground and I am flying. Maybe you are thinking of flying "well"?
1. A wing needs differential pressure, air flowing over it is the conventional way that it happens.
2. I suppose, orientation of the plane was not static.
3. I don't recall any significant wind, but other effects may have been occurring, like warm air rising off the runway.
4. I still don't recall any significant wind.
5. Disagree, off the ground and I am flying. Maybe you are thinking of flying "well"?
08-09-2009, 10:55 PM
#82
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I've been watching this discussion for a while. As a pilot myself I would call a zero airspeed a stall although in modern aircraft you get plenty of warning. Another but unlikely possibility was a pitot failure, blocked or iced up (but I doubt it.
If we were talking about ground speed, that's another story. Take a light aircraft and a 100 knot headwind and you can fly backwards!
Zero airspeed says no lift and even worse, no control since the control surfaces depend on airflow over them to give control over pitch yaw and roll.
Regards,
If we were talking about ground speed, that's another story. Take a light aircraft and a 100 knot headwind and you can fly backwards!
Zero airspeed says no lift and even worse, no control since the control surfaces depend on airflow over them to give control over pitch yaw and roll.
Regards,
08-09-2009, 11:54 PM
#83
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Mark, any pilot that has ever done a tailslide has done 0 airspeed.
And yes, I have done them in the Super Decathlon and other types.
So I guess I was not flying at that point, according to you, so should I go back and take time out of my log books since according to you I was not flying?
Most times when you do a Hammerhead you carry a bit of airspeed before you kick the rudder.
BTW, it is Lift = Weight, not gravity, like you have said, these are 2, of the four forces of flight.
And WTF do you mean by "porpoise into a hammer head stall"?
You are also getting "Relative wind" confused with other things, it has nothing to do with the movement over the ground.
If I recall, relative wind is the difference between the chord line and the angle of attack, but it has been many years since I did the ground school stuff instead of trying to figure out how to make all these things work with out thinking.
Greg
And yes, I have done them in the Super Decathlon and other types.
So I guess I was not flying at that point, according to you, so should I go back and take time out of my log books since according to you I was not flying?
Most times when you do a Hammerhead you carry a bit of airspeed before you kick the rudder.
BTW, it is Lift = Weight, not gravity, like you have said, these are 2, of the four forces of flight.
And WTF do you mean by "porpoise into a hammer head stall"?
You are also getting "Relative wind" confused with other things, it has nothing to do with the movement over the ground.
If I recall, relative wind is the difference between the chord line and the angle of attack, but it has been many years since I did the ground school stuff instead of trying to figure out how to make all these things work with out thinking.
Greg
For movement relative to the ground, no air speed, all you could have done is porpoise into a hammer head stall where you would be at 0 airspeed and ground speed for a brief second in still air.
In a nut shell, you have NO idea what the true wind component was at the time this happened. reletive wind varies in as little as 50-100ft increments. You could have a slight headwind of more than 10-15knots and at full power, flaps, and attitude, you could have stood still reletive to the ground for a brief period of time. At 0 air speed indicated, the wings would not be flying, so the plane is not flying.
you said you dont need charts and diagrams to show this, so just give me some better explaination of what you think was happening
mk
In a nut shell, you have NO idea what the true wind component was at the time this happened. reletive wind varies in as little as 50-100ft increments. You could have a slight headwind of more than 10-15knots and at full power, flaps, and attitude, you could have stood still reletive to the ground for a brief period of time. At 0 air speed indicated, the wings would not be flying, so the plane is not flying.
you said you dont need charts and diagrams to show this, so just give me some better explaination of what you think was happening
mk
08-10-2009, 12:16 AM
#84
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Hey! In a tail slide you still have airspeed only it is negative but there is still airflow over the control surfaces (thank god!) I figure you stunt guys should have airspeed displays that read positive AND negative
08-10-2009, 03:35 AM
#85
Rennlist Member
yes, Ive done a tail slide before, i called it a hammer head by accident. I was firing out the note too quickly. sorry about that. yes, weight, not gravity.
Thust and drag are the other two forces. yes, its been 30 years since my ground school!
Now, you know that we are not talking about "flying " here. we are talking about someone seeing 0 indicated air speed an was staying aloft. what I meant by the porpoise comment was that if you bounce up, and stall with a high enough angle of attack , and full power/flaps, you might get close to 0 indicated. thats it. just trying to figure out what he saw.
I was talking about wind, not relative wind as in the books. yes, relative wind is the wind, releative to the cord of the wing or angle of attack If I remember correctly. I was talking about, specifically , a head wind that would give you 0 ground speed as we all know here, but indicated would still have to be above stall speed, and if its a cessna 172, its about 55mph and near 40mph with full power and flaps, but I dont remember, so check the manual for those number.
mk
Thust and drag are the other two forces. yes, its been 30 years since my ground school!
Now, you know that we are not talking about "flying " here. we are talking about someone seeing 0 indicated air speed an was staying aloft. what I meant by the porpoise comment was that if you bounce up, and stall with a high enough angle of attack , and full power/flaps, you might get close to 0 indicated. thats it. just trying to figure out what he saw.
I was talking about wind, not relative wind as in the books. yes, relative wind is the wind, releative to the cord of the wing or angle of attack If I remember correctly. I was talking about, specifically , a head wind that would give you 0 ground speed as we all know here, but indicated would still have to be above stall speed, and if its a cessna 172, its about 55mph and near 40mph with full power and flaps, but I dont remember, so check the manual for those number.
mk
Mark, any pilot that has ever done a tailslide has done 0 airspeed.
And yes, I have done them in the Super Decathlon and other types.
So I guess I was not flying at that point, according to you, so should I go back and take time out of my log books since according to you I was not flying?
Most times when you do a Hammerhead you carry a bit of airspeed before you kick the rudder.
BTW, it is Lift = Weight, not gravity, like you have said, these are 2, of the four forces of flight.
And WTF do you mean by "porpoise into a hammer head stall"?
You are also getting "Relative wind" confused with other things, it has nothing to do with the movement over the ground.
If I recall, relative wind is the difference between the chord line and the angle of attack, but it has been many years since I did the ground school stuff instead of trying to figure out how to make all these things work with out thinking.
Greg
And yes, I have done them in the Super Decathlon and other types.
So I guess I was not flying at that point, according to you, so should I go back and take time out of my log books since according to you I was not flying?
Most times when you do a Hammerhead you carry a bit of airspeed before you kick the rudder.
BTW, it is Lift = Weight, not gravity, like you have said, these are 2, of the four forces of flight.
And WTF do you mean by "porpoise into a hammer head stall"?
You are also getting "Relative wind" confused with other things, it has nothing to do with the movement over the ground.
If I recall, relative wind is the difference between the chord line and the angle of attack, but it has been many years since I did the ground school stuff instead of trying to figure out how to make all these things work with out thinking.
Greg
08-10-2009, 03:37 AM
#86
Rennlist Member
If you are good with the rudder, its amazing how much control you can have in a stall and moderate power and with flaps down. Goes to his point that some of that thrust gives air flow over the inner wing area, which does give some lift. But, with a 172, not enough to keep it aloft, flying, I mean , at a constant altitude, relative to the ground, with no head wind.(man , have to watch what I say here! )
) I've been watching this discussion for a while. As a pilot myself I would call a zero airspeed a stall although in modern aircraft you get plenty of warning. Another but unlikely possibility was a pitot failure, blocked or iced up (but I doubt it.
If we were talking about ground speed, that's another story. Take a light aircraft and a 100 knot headwind and you can fly backwards!
Zero airspeed says no lift and even worse, no control since the control surfaces depend on airflow over them to give control over pitch yaw and roll.
Regards,
If we were talking about ground speed, that's another story. Take a light aircraft and a 100 knot headwind and you can fly backwards!
Zero airspeed says no lift and even worse, no control since the control surfaces depend on airflow over them to give control over pitch yaw and roll.
Regards,
Last edited by mark kibort; 08-10-2009 at 12:36 PM.
08-10-2009, 08:02 AM
#87
Nordschleife Master
Exactly why I was flubbing the landing I don't remember, but when I was still a good 20 feet off the runway with the intention of landing (touch and go) my rate of descent was too high and I think I was going too slow, but could be I forgot to go to full flaps.
During the remaining 20 feet or so of descent I attempted corrective measures, which may have included full flaps and/or throttle and pulling back on the yoke.
Touch down turned into a hard bounce as impact, flaps, throttle, yoke, and wing distance to the ground all added together. It did indeed feel very much like a stall, and I attempted the same recovery as from a stall, pushing the yoke forward and trading altitude for speed.
All of my recollection of the top of that bounce was motion stopping, airspeed on zero, ground not moving, hanging briefly, followed by descent to a few feet above the runway and a very slow recovery of airspeed back to Vrot and climbing back into the pattern. I consider everything after leaving the ground as flying, and do not recall any wind.
More detail will have to wait for my memoirs.
During the remaining 20 feet or so of descent I attempted corrective measures, which may have included full flaps and/or throttle and pulling back on the yoke.
Touch down turned into a hard bounce as impact, flaps, throttle, yoke, and wing distance to the ground all added together. It did indeed feel very much like a stall, and I attempted the same recovery as from a stall, pushing the yoke forward and trading altitude for speed.
All of my recollection of the top of that bounce was motion stopping, airspeed on zero, ground not moving, hanging briefly, followed by descent to a few feet above the runway and a very slow recovery of airspeed back to Vrot and climbing back into the pattern. I consider everything after leaving the ground as flying, and do not recall any wind.
More detail will have to wait for my memoirs.
08-10-2009, 09:40 AM
#88
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I LOLed at that Mark, that is exactly how I did my first tail slide.
Ok, you have answered my question about if you fly or not.
I know nothing about a dyno, so carry on.
Ok, you have answered my question about if you fly or not.
I know nothing about a dyno, so carry on.
yes, Ive done a tail slide before, i called it a hammer head by accident. I was firing out the note too quickly. sorry about that. yes, weight, not gravity.
Thust and drag are the other two forces. yes, its been 30 years since my ground school!
Now, you know that we are not talking about "flying " here. we are talking about someone seeing 0 indicated air speed an was staying aloft. what I meant by the porpoise comment was that if you bounce up, and stall with a high enough angle of attack , and full power/flaps, you might get close to 0 indicated. thats it. just trying to figure out what he saw.
I was talking about wind, not relative wind as in the books. yes, relative wind is the wind, releative to the cord of the wing or angle of attack If I remember correctly. I was talking about, specifically , a head wind that would give you 0 ground speed as we all know here, but indicated would still have to be above stall speed, and if its a cessna 172, its about 55mph and near 40mph with full power and flaps, but I dont remember, so check the manual for those number.
mk
Thust and drag are the other two forces. yes, its been 30 years since my ground school!
Now, you know that we are not talking about "flying " here. we are talking about someone seeing 0 indicated air speed an was staying aloft. what I meant by the porpoise comment was that if you bounce up, and stall with a high enough angle of attack , and full power/flaps, you might get close to 0 indicated. thats it. just trying to figure out what he saw.
I was talking about wind, not relative wind as in the books. yes, relative wind is the wind, releative to the cord of the wing or angle of attack If I remember correctly. I was talking about, specifically , a head wind that would give you 0 ground speed as we all know here, but indicated would still have to be above stall speed, and if its a cessna 172, its about 55mph and near 40mph with full power and flaps, but I dont remember, so check the manual for those number.
mk
08-10-2009, 12:35 PM
#89
Rennlist Member
I think we know what happened now. again, if you define "flying" by just a moment in the air, above the ground, for some smalll duration of time, yes, he could have been "flying" at low air speed (not 0) for a brief time. He even said, he traded altitude for some air speed, and then landed. pretty tough to have no air flow over the wings, and the thrust from the prop doesnt count for much.
Blown, yes, ive been flying off and on for 30 years. we had a couple of planes in the family growng up. Ill have to post some video of some high speed flybys in a pumped up Aerostar. Anyway, no much at all in the last 10 years. Anyway, what is your point? anyway, you are doing tail slides on final approach or landing?
mk
Blown, yes, ive been flying off and on for 30 years. we had a couple of planes in the family growng up. Ill have to post some video of some high speed flybys in a pumped up Aerostar. Anyway, no much at all in the last 10 years. Anyway, what is your point? anyway, you are doing tail slides on final approach or landing?
mk
08-10-2009, 12:42 PM
#90
Rennlist Member
I know. Kind of obvious what you were explaining. I was just razzing you about flying with no indicated air speed. If falling, is flying, then yes you were flying.
you know as well as anyone, you cant fly (maintain altitude) with 0 air speed, even with full power and flaps. It may seem like it, but you will always be moving foward, if there is no headwind. IN a headwind, you could be standing still, relative the ground. (i.e. true airspeed, being 0).
all you really need to do is map out the forces on paper and see how everything matches up. full power and flaps with a high angle of attack will slow the stall speed, but not negate it. Like i said, its in the manual. (stall vs stall air speed with full power and flaps.) I just cant find the manual and dont remember.
mk
you know as well as anyone, you cant fly (maintain altitude) with 0 air speed, even with full power and flaps. It may seem like it, but you will always be moving foward, if there is no headwind. IN a headwind, you could be standing still, relative the ground. (i.e. true airspeed, being 0).
all you really need to do is map out the forces on paper and see how everything matches up. full power and flaps with a high angle of attack will slow the stall speed, but not negate it. Like i said, its in the manual. (stall vs stall air speed with full power and flaps.) I just cant find the manual and dont remember.
mk
Exactly why I was flubbing the landing I don't remember, but when I was still a good 20 feet off the runway with the intention of landing (touch and go) my rate of descent was too high and I think I was going too slow, but could be I forgot to go to full flaps.
During the remaining 20 feet or so of descent I attempted corrective measures, which may have included full flaps and/or throttle and pulling back on the yoke.
Touch down turned into a hard bounce as impact, flaps, throttle, yoke, and wing distance to the ground all added together. It did indeed feel very much like a stall, and I attempted the same recovery as from a stall, pushing the yoke forward and trading altitude for speed.
All of my recollection of the top of that bounce was motion stopping, airspeed on zero, ground not moving, hanging briefly, followed by descent to a few feet above the runway and a very slow recovery of airspeed back to Vrot and climbing back into the pattern. I consider everything after leaving the ground as flying, and do not recall any wind. More detail will have to wait for my memoirs.
During the remaining 20 feet or so of descent I attempted corrective measures, which may have included full flaps and/or throttle and pulling back on the yoke.
Touch down turned into a hard bounce as impact, flaps, throttle, yoke, and wing distance to the ground all added together. It did indeed feel very much like a stall, and I attempted the same recovery as from a stall, pushing the yoke forward and trading altitude for speed.
All of my recollection of the top of that bounce was motion stopping, airspeed on zero, ground not moving, hanging briefly, followed by descent to a few feet above the runway and a very slow recovery of airspeed back to Vrot and climbing back into the pattern. I consider everything after leaving the ground as flying, and do not recall any wind.
More detail will have to wait for my memoirs.