Downwind turn Myth
11-25-2010, 11:22 PM
#501
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RE: Downwind turn Myth
I am a private pilot and this is a extremely simplistic explanation. As far as the wing is concerned indicated air speed is all that matters. I have infact flew a cessna 150 backward in a extreme head wind. An abrupt change in wind direction is called wind shear(not a myth) and not a happy situation when on final at low altitude(I also did this) it took a lot of effort to pop the vacuum I pulled on the wedgee created. The loss of lift created by a large change of wind direction is a myth only it you have infinate power which can overcome it imediatly as described by the author. you can only really appreciate wind shear if you have experienced it.
11-25-2010, 11:26 PM
#503
Senior Member
RE: Downwind turn Myth
ORIGINAL: Captainbob
...
I am always amazed when this discussion comes up because, as highhorse said, it comes up in full scale aviation circles as well. Even with experienced professionals!!!! What’s at work here is the idea of perspective. The R/C pilot and the full scale pilot have different perspectives. The R/C pilot is not traveling with the airplane. He views it from a “Fixed†point on the ground. When the R/C pilot does a loop with a high wind blowing he must adjust control inputs to keep the loop “round†and front of him. The full scale pilot when doing a loop without reference to the ground makes no such adjustments. Imagine the pilot of an F-4 Phantom doing a loop. He starts the maneuver at 10,000 ft. and 600 kts., he starts the pull up at 4G’s and plans to come over the top at 200kts and at 35,000ft. He pulls hard down the back side reaching maybe 5G’s at the seven o’clock position then levels again at 10,000ft. and 600kts. He pats himself on the back for a perfect maneuver. But to the observer on the ground it was a lousy loop, because the Phantom’s exit point is way down wind of it’s entry point due to the 150kt. headwind, that day, at the top of the loop.
...
...
I am always amazed when this discussion comes up because, as highhorse said, it comes up in full scale aviation circles as well. Even with experienced professionals!!!! What’s at work here is the idea of perspective. The R/C pilot and the full scale pilot have different perspectives. The R/C pilot is not traveling with the airplane. He views it from a “Fixed†point on the ground. When the R/C pilot does a loop with a high wind blowing he must adjust control inputs to keep the loop “round†and front of him. The full scale pilot when doing a loop without reference to the ground makes no such adjustments. Imagine the pilot of an F-4 Phantom doing a loop. He starts the maneuver at 10,000 ft. and 600 kts., he starts the pull up at 4G’s and plans to come over the top at 200kts and at 35,000ft. He pulls hard down the back side reaching maybe 5G’s at the seven o’clock position then levels again at 10,000ft. and 600kts. He pats himself on the back for a perfect maneuver. But to the observer on the ground it was a lousy loop, because the Phantom’s exit point is way down wind of it’s entry point due to the 150kt. headwind, that day, at the top of the loop.
...
Or lines on the canopy.
11-25-2010, 11:27 PM
#504
RE: Downwind turn Myth
Brent,
You have directed your last post to me, but I believe that you have confused my previous post #462 of page 19 with somebody's else.
I have made no reference to any typo or misleading information given by you.
In my post, I tried to explain that you have many reasons to feel what you describe regarding turns.
The conditions of your flights are very different from the ideal conditions that have been discussed in this thread.
I do respect your work and your experience, and consider you no less pilot than any other.
If I have offended you in any way, I offer my sincere appologies.
You have directed your last post to me, but I believe that you have confused my previous post #462 of page 19 with somebody's else.
I have made no reference to any typo or misleading information given by you.
In my post, I tried to explain that you have many reasons to feel what you describe regarding turns.
The conditions of your flights are very different from the ideal conditions that have been discussed in this thread.
I do respect your work and your experience, and consider you no less pilot than any other.
If I have offended you in any way, I offer my sincere appologies.
11-25-2010, 11:33 PM
#505
RE: Downwind turn Myth
OMG, we're at 21 pages and counting. Aaaarrrhhhh!!! D-oh!!!!
Would someone PLEASE post an explanation using the words INERTIA, RELATIVITY, and PELICANS to describe how this ISN'T a myth but is actually a true phenomenon.
No hecklers or educated replies, please. If you have more than 2000hrs of experience flying actual full-scale aircraft with paying passengers on-board, please do not respond; you have been brainwashed by the FAA and/or your instruments.
Only the uninformed can explain the inexplicable.
Thanks,
Jim
Would someone PLEASE post an explanation using the words INERTIA, RELATIVITY, and PELICANS to describe how this ISN'T a myth but is actually a true phenomenon.
No hecklers or educated replies, please. If you have more than 2000hrs of experience flying actual full-scale aircraft with paying passengers on-board, please do not respond; you have been brainwashed by the FAA and/or your instruments.
Only the uninformed can explain the inexplicable.
Thanks,
Jim
11-25-2010, 11:36 PM
#506
Senior Member
RE: Downwind turn Myth
ORIGINAL: hofer
Hi again,
Two more facts here that leave many RC-modelers disbelieving the basic physics :
-as mentioned before, in RC-modeling, all movements of the plane are refered to a ground fix point (you as the pilot !!)
all the time and intuitivly
-we fly our little ships with no or little hesitation in windspeeds reaching, lets say, 50% of the take off or approach
speeds of those planes and therefore produicing some hardly believable behaviour when controlled from your ground
based fix point (say your eyes !!).
...
Hi again,
Two more facts here that leave many RC-modelers disbelieving the basic physics :
-as mentioned before, in RC-modeling, all movements of the plane are refered to a ground fix point (you as the pilot !!)
all the time and intuitivly
-we fly our little ships with no or little hesitation in windspeeds reaching, lets say, 50% of the take off or approach
speeds of those planes and therefore produicing some hardly believable behaviour when controlled from your ground
based fix point (say your eyes !!).
...
Flying our toys when the winds are equal to the takeoff speed is fun!
The wheels don't roll at all, and the plane just goes up, in a level attitude, when the power is advanced beyond that needed to keep it stationary in the wind.
National Geographic showed some pelicans and albatri doing just that.. spreading their wings while facing the oncoming wind, and gently lifting off the ground with no forward or aft motion.
Landings can be also just losing altitude at a constant pitch angle, with no forward motion, by playing with the throttle.
On or the slope, the elevator.
11-25-2010, 11:37 PM
#507
RE: Downwind turn Myth
ORIGINAL: brenthampton79
Lnewqban
no typo and i know it is very contridicting, but im not going to lie and tell everyone whats not really happening in the cockpit of an 802, and yes I have plenty of time to look at the airspeed indicator on a half-mile long field at the midpoint. I am not an aerodynamic engineer or some einstein all I'm saying is when I went from flying corporate and charter to flying an ag plane 5 foot off the deck all day the down wind turn argument was alive in my own mind even though I used to agree with the other ''proffesional pilots'' which I'm apparently not now according to some since im just an ''ag pilot''. but there is something to this to what level and extent I don't know, but there is something going on, On the downwind side lets say the wind is out of the north and I am south bound on the field, the IAS will be higher on that run, with on that pull down wind it will take longer in time and distance ''obviously'' than the turn on the other end of the field, when i am northbound and heading into the wind with a slower airspeed. I can tell you something the downwind side takes forever to make that turn in time and the altitude I gain on the pull up never seems the same as the other end and if I'm in the airmass then a 2 g pull out should equate the same altitude gain. Like I said before I can't explain it and don't espect anyone to agree with me unless they actually did the same thing I do for a living, and I mean the exact same thing not a c-130 or something, which for the guy that did that thank you for your service in the military. I beleive there is some stuff going on there that I agree with you that may belong in the aerodynamic are or better yet on mythbusters, and I'm okay with being wrong if they can explain it to me in a simple enough way and explain what those weird sensations I feel and crazy indications I see in the cockpit, plus when I see it in the cockpit it refutes everything I learned while I was engineering school and all the publications I have read in the past, but I am from the Show me state, like I said if you can prove it to me I can say your right and i'm wrong, after all I am married so its not like i haven't had to do it before
Lnewqban
no typo and i know it is very contridicting, but im not going to lie and tell everyone whats not really happening in the cockpit of an 802, and yes I have plenty of time to look at the airspeed indicator on a half-mile long field at the midpoint. I am not an aerodynamic engineer or some einstein all I'm saying is when I went from flying corporate and charter to flying an ag plane 5 foot off the deck all day the down wind turn argument was alive in my own mind even though I used to agree with the other ''proffesional pilots'' which I'm apparently not now according to some since im just an ''ag pilot''. but there is something to this to what level and extent I don't know, but there is something going on, On the downwind side lets say the wind is out of the north and I am south bound on the field, the IAS will be higher on that run, with on that pull down wind it will take longer in time and distance ''obviously'' than the turn on the other end of the field, when i am northbound and heading into the wind with a slower airspeed. I can tell you something the downwind side takes forever to make that turn in time and the altitude I gain on the pull up never seems the same as the other end and if I'm in the airmass then a 2 g pull out should equate the same altitude gain. Like I said before I can't explain it and don't espect anyone to agree with me unless they actually did the same thing I do for a living, and I mean the exact same thing not a c-130 or something, which for the guy that did that thank you for your service in the military. I beleive there is some stuff going on there that I agree with you that may belong in the aerodynamic are or better yet on mythbusters, and I'm okay with being wrong if they can explain it to me in a simple enough way and explain what those weird sensations I feel and crazy indications I see in the cockpit, plus when I see it in the cockpit it refutes everything I learned while I was engineering school and all the publications I have read in the past, but I am from the Show me state, like I said if you can prove it to me I can say your right and i'm wrong, after all I am married so its not like i haven't had to do it before
I have very limited experience as a full size pilot, (just 170 hrs in Cessnaa), and my formal training in Aeronautics only extends to what they taught us at PPL stage, so I am far less qualified then many here, including you of course. However I firmly believe the down wind turn sag/zoom scenario is a myth.
I respectfully suggest that the following explanation may be why you experience what you do when flying low level.
The whole debate of “wind not affecting airspeed†depends on the premise that the wind being flown in, is constant velocity and constant direction.
When you fly close to the ground, the wind is anything but “Constant Stateâ€. Apart from turbulence created by obstacles on the ground, there is also a natural wind gradient due to the drag of the air mass as it flows over the ground. As altitude increases, wind velocity increases, and it tends to vary in direction as well.
As already mentioned several times in this thread, when flying low level, you are also subject to a lot of visual clues on the ground, which your brain will tend to rely upon to estimate speeds. (After all you cannot see the air.)
None of these factors are apparent when you are in the corporate jet at 33,000 feet.
Couple this turbulent and varying wind, with the increased visual stimulus, I am not surprised that you experience what you do.
However, the science and physics still hold true. Wind has no affect on airspeed, either in straight and level flight, or in a turn.
Roger
11-25-2010, 11:48 PM
#508
RE: Downwind turn Myth
As I recall you brought up inertia, truly a factor in gusts. Ibrought up relativity to try to explain that inertia is also relative to the wind. Perhaps I could have better explained this. You also brought up pelicans, and Iguess that is a bit beyond me. Though I still maintain that Australian pelicans fly inverted.
11-26-2010, 12:22 AM
#510
RE: Downwind turn Myth
ORIGINAL: Sport_Pilot
As I recall you brought up inertia, truely a facter in gusts. I brought up relativity to try to explain that inertia is also relative to the wind. Perhaps I could have better explained this. You also brought up pelicans, and I guess that is a bit beyond me. Though I still maintain that Australian pelicans fly inverted.
As I recall you brought up inertia, truely a facter in gusts. I brought up relativity to try to explain that inertia is also relative to the wind. Perhaps I could have better explained this. You also brought up pelicans, and I guess that is a bit beyond me. Though I still maintain that Australian pelicans fly inverted.
2) Relativity is irrelevant (to this thread)
3) There is nothing that YOU can explain (IMHO based on your other posts in RCU)
4) David Gladwin brought up pelicans
5) Pelicans can fly in any orientation they want
H+K,
Jim
11-26-2010, 02:26 AM
#511
RE: Downwind turn Myth
I cant believe the utter lack of education/logic shown here. The original poster is quite correct. Wind (excluding turbulence) does not affect aircraft AT ALL. It DOES affect the perception of the pilot though of what the aircraft is seen to be doing. Hence the downwind turn stalls since the pilot tries to slow the perceived increase in airspeed, and in effect reducing REAL airspeed.
To Add to the stupid parables of "proof" consider flying an indoor model in circles inside a large cargo jet. One second it flies Mach .8 forward the next Mach .8 BACKWARDS.
geez.....
To Add to the stupid parables of "proof" consider flying an indoor model in circles inside a large cargo jet. One second it flies Mach .8 forward the next Mach .8 BACKWARDS.
geez.....
11-26-2010, 02:37 AM
#512
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RE: Downwind turn Myth
highhorse:
I've seen a couple of psych articles discussing this phenomena. Sad but true.
To the myth believers/proponents: Notice that many of the people who are trying to debunk this are pro pilots, and many of us have thousands of hours instructing and answering similar questions of students. NONE of said pilots believe the myth is true. Not that all these pilots are infallible, but on this one subject why do think they ALL agree? Some big conspiracy? Come on, present some science, some facts, some experts of your own.
(In the case of ag flying, I believe the visual cues and tighter-than-realized downwind banks trick your perceptions). Just my .02. Time for a beer!
Ed
I'd just say that the majority of the myth believers were grossly mis-led at an early and gullible period in their educations, and have since become emotionally invested in the wrong conclusions, even to the point that they would rather be consistent than informed,
To the myth believers/proponents: Notice that many of the people who are trying to debunk this are pro pilots, and many of us have thousands of hours instructing and answering similar questions of students. NONE of said pilots believe the myth is true. Not that all these pilots are infallible, but on this one subject why do think they ALL agree? Some big conspiracy? Come on, present some science, some facts, some experts of your own.
(In the case of ag flying, I believe the visual cues and tighter-than-realized downwind banks trick your perceptions). Just my .02. Time for a beer!
Ed
11-26-2010, 02:43 AM
#513
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RE: Downwind turn Myth
Your statement in the bold red writing is untrue. Whether a aircraft in the air or on the ground airspeed is airspeed. Airflow over the wings is what provides lift. If you are flying into a 10kt head wind at 40kts and stall for you aircraft is 35kts. You are still flying. Now if you make a 180deg turn you are going to trade a lot of alt. for airspeed to continue flying. Unless you provide alot of power to increse you airspeed.
11-26-2010, 02:56 AM
#515
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RE: Downwind turn Myth
Whether a aircraft in the air or on the ground airspeed is airspeed. Airflow over the wings is what provides lift. If you are flying into a 10kt head wind at 40kts and stall for you aircraft is 35kts. You are still flying. Now if you make a 180deg turn you are going to trade a lot of alt. for airspeed to continue flying. Unless you provide alot of power to increse you airspeed.
11-26-2010, 03:33 AM
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RE: Downwind turn Myth
ORIGINAL: roger.alli
Rob,
Nicely put. Your post elegantly describes the truth of this myth.
Constant state winds have NO affect on an aircrafts airspeed, OR INERITA, weather in it be flying straight and level, or in a turn.
I was racking my brains trying to think of an elegant way to describe the affect, without using vectors or the word ''relativly''.
Thanks.
Roger
ORIGINAL: rjbob
The following example is indisputable. Anyone who disputes the following is ignorant.
The following example is indisputable. Anyone who disputes the following is ignorant.
Rob,
Nicely put. Your post elegantly describes the truth of this myth.
Constant state winds have NO affect on an aircrafts airspeed, OR INERITA, weather in it be flying straight and level, or in a turn.
I was racking my brains trying to think of an elegant way to describe the affect, without using vectors or the word ''relativly''.
Thanks.
Roger
It's not an affect, it's an EFFECT.
11-26-2010, 04:40 AM
#517
RE: Downwind turn Myth
ORIGINAL: rcjets_63
4) David Gladwin brought up pelicans
5) Pelicans can fly in any orientation they want
4) David Gladwin brought up pelicans
5) Pelicans can fly in any orientation they want
Many Australian birds DO fly backwards, ( which means their FIRST turn is usually INTO wind, they're not stupid !) as well as upside down. It keeps the dust out of their eyes.
I see someone was suggesting Pecan Pie for desert this thanksgiving , is that PELICAN pie with the LI removed. ? Does it taste like turkey ?
A very happy Thanksgiving to all Americans (we love you all really !) young whippersnapper junior pilots with only 11k hours included !
Regards, David.
11-26-2010, 05:08 AM
#518
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RE: Downwind turn Myth
Edited
Some of the things that I've learned fo far:
One full scale pilot observes a gain in speed flying downwind and loss of speed upwind. This pilot corrected his statement and now reports the opposite: loss of speed flying downwind and gain upwind. And this is contradictory to the downwind myth theory. Other FSpilots report no changes in air speed upwind or downwind.
One operator of a parachute style plane reports constant changes in altitude when turning downwind. No explanation for this I can recall. Maybe it's the loss of speed in a turn theory.
One widely held belief is that a plane loses air speed in a turn. That is refuted by the FS pilots who state that that doesn't happen in their experience. After rereading, one pilot reports loseing 2kts, one infers loseing 4kts, and one does state no loss of speed, but does refer to loss or gain of altitude. Oops, my mistake, I clearly need a better memory.
Some of the things Ithink about.
Scale factor makes a difference between full scale and models. What is true for full scale doesn't always hold true for models. Reynolds numbers are widely held to be true and make a difference due to just size.
Models can frequently fly with no air speed. Just watch a 3D model hover. Whatever the relationship to lift on the wing and flying can be negated by certain manuvers.
Drag and lift on a plane certainly changes when a different profile is presented to airflow. One of my most memorable memories was watching a nickel glider I bought take off into the wind and go into a series of upward zooms followed by a stall that droped the nose and a dive untill it zoomed up again. It flew higher and higher until it was out of sight. My current theory is that the wind imparted enough energy to the plane to elevate it ever higher. It didn't look as if airflow over the wing was lifting it, it looked like the wind blew on the underside of the wing and blew it upwards.
I'm going flying later today. I'll try to think of some experiments to do since Iusually have a wind to work with. One will definately be an upward line with a turn into and away from the wind.
And just remember, this thread started with a story about a loop and then turned into a discussion about a turn.
Some of the things that I've learned fo far:
One full scale pilot observes a gain in speed flying downwind and loss of speed upwind. This pilot corrected his statement and now reports the opposite: loss of speed flying downwind and gain upwind. And this is contradictory to the downwind myth theory. Other FSpilots report no changes in air speed upwind or downwind.
One operator of a parachute style plane reports constant changes in altitude when turning downwind. No explanation for this I can recall. Maybe it's the loss of speed in a turn theory.
One widely held belief is that a plane loses air speed in a turn. That is refuted by the FS pilots who state that that doesn't happen in their experience. After rereading, one pilot reports loseing 2kts, one infers loseing 4kts, and one does state no loss of speed, but does refer to loss or gain of altitude. Oops, my mistake, I clearly need a better memory.
Some of the things Ithink about.
Scale factor makes a difference between full scale and models. What is true for full scale doesn't always hold true for models. Reynolds numbers are widely held to be true and make a difference due to just size.
Models can frequently fly with no air speed. Just watch a 3D model hover. Whatever the relationship to lift on the wing and flying can be negated by certain manuvers.
Drag and lift on a plane certainly changes when a different profile is presented to airflow. One of my most memorable memories was watching a nickel glider I bought take off into the wind and go into a series of upward zooms followed by a stall that droped the nose and a dive untill it zoomed up again. It flew higher and higher until it was out of sight. My current theory is that the wind imparted enough energy to the plane to elevate it ever higher. It didn't look as if airflow over the wing was lifting it, it looked like the wind blew on the underside of the wing and blew it upwards.
I'm going flying later today. I'll try to think of some experiments to do since Iusually have a wind to work with. One will definately be an upward line with a turn into and away from the wind.
And just remember, this thread started with a story about a loop and then turned into a discussion about a turn.
11-26-2010, 07:06 AM
#519
RE: Downwind turn Myth
ORIGINAL: highhorse
Draw a loop on a piece of paper. Then do it with your eyes closed till you can consistently make a fairlt round loop. THEN do the same thing as someone else slowly pulls the paper sideways.
Draw a loop on a piece of paper. Then do it with your eyes closed till you can consistently make a fairlt round loop. THEN do the same thing as someone else slowly pulls the paper sideways.
I agree with all you have written.
I particularly like the analogy of drawing a round loop (works for drawing a circle as well) on a moving sheet of paper.
I hope you won't mind if I quote that one.
You started with the statement (in red)
Once an a/c has broken ground, steady state winds have no effect on airspeed (hence, lift) whatsoever, and airspeed does not change simply because one is flying upwind, downwind, crosswind, or even when alternating between any combinations of the above. Period. That is the beginning, middle, and end of the story.
Agreed!!!!!
I have had 50 years of model flying, 31 years of flying airliners (twin props up to 747) and before that a 4 year degree course in Aeronautics and I have never ever in all that time heard a convincing argument for the wind effect myth.
I have observed the effects of turning in a 150 knot wind (over Canada), I have trimmed a model to fly perfect level circles with the Tx on the ground, and I have done the maths, integrating the momentum and KE changes in a turn.
Sorry if I have repeated what others have written, I have not read the entire thread, but I believe the truth can't be repeated too often.
11-26-2010, 07:34 AM
#520
RE: Downwind turn Myth
Hi flythesky,
How can you comment that some full size pilots say an airplane is NOT loosing airspeed in a turn ?
Of course it will loose airspeed !! But as agreed now by more and more guys here not because of the windconditions its flying in, but due do the fact that any manoever
in level flight will cost you energy ! While turning, you have to apply energy to your ship, either by using more thrust to stay level or by giving away potential energy-say descending !
Even the cleanest plane is far away of beeing a perpetum mobile !
see you
How can you comment that some full size pilots say an airplane is NOT loosing airspeed in a turn ?
Of course it will loose airspeed !! But as agreed now by more and more guys here not because of the windconditions its flying in, but due do the fact that any manoever
in level flight will cost you energy ! While turning, you have to apply energy to your ship, either by using more thrust to stay level or by giving away potential energy-say descending !
Even the cleanest plane is far away of beeing a perpetum mobile !
see you
11-26-2010, 08:09 AM
#522
RE: Downwind turn Myth
ORIGINAL: hofer
Hi flythesky,
How can you comment that some full size pilots say an airplane is NOT loosing airspeed in a turn ?
Of course it will loose airspeed !! But as agreed now by more and more guys here not because of the windconditions its flying in, but due do the fact that any manoever
in level flight will cost you energy ! While turning, you have to apply energy to your ship, either by using more thrust to stay level or by giving away potential energy-say sinking !
Even the cleanest plane is far away of beeing a perpetum mobile !
see you
Hi flythesky,
How can you comment that some full size pilots say an airplane is NOT loosing airspeed in a turn ?
Of course it will loose airspeed !! But as agreed now by more and more guys here not because of the windconditions its flying in, but due do the fact that any manoever
in level flight will cost you energy ! While turning, you have to apply energy to your ship, either by using more thrust to stay level or by giving away potential energy-say sinking !
Even the cleanest plane is far away of beeing a perpetum mobile !
see you
The thread is still going on I see, a pity, it is a waste of valuable modeling time.
I did tell you about wind gradient. As result of this phenomenon the needed accelerating or possible deceleration to keep airspeed when changing altitude on low flight levels or starting and landing.
I also did tell you about increasing of stall speed under load (while turning) and suggest to take a look at dynamic soaring.
Suggestion
Maybe it is a good point to go back to the glider again, because sometimes I see a TE variometer in operator room so maybe there is an engineer-pilot that knows something about it that is useable.
Cees
11-26-2010, 08:28 AM
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RE: Downwind turn Myth
ORIGINAL: Doug Cronkhite
This thread makes my head hurt.
Oh.. and just for the record.. I'm in the Highhorse camp..
This thread makes my head hurt.
Oh.. and just for the record.. I'm in the Highhorse camp..
But bring him near the ground, as if to land, and now he MUST use the ground as a reference, he has no choice, he needs to line up with the runway. So he inputs controls to that effect and is affected by an incorrect perception of his actual airpseed. That's what scews up the inexperienced pilot.
The downwind turn is not a factor at altitude. But it IS near the ground. THAT's what the discussion is about,,, why sometimes, a downwind turn, NEAR THE GROUND, when making a landing, can trip up an inexperienced pilot and cause an accident. No myth, it's real.
I'll tell you what a REAL myth is.
One: 1/2A engines can't be made to throttle well. Because,,, they run too hot, the carb orifices are too small, sub-piston induction, combustion chamber is too small,,, etc. take your pick.
Here, http://www.youtube.com/user/hopeso#p/u/5/mRPgkYjReTA is a VA .049 throttling perfectly. How? Just the addition of an adjustable airbleed,,, a means to adjust the mixture at idle. MOST throttled 1/2As do not have this feature and throttle poorly. The addition of the feature corrects the problem. All the excuses for poor throttling on 1/2A engines are just that,excuses and poor throttling of 1/2As is a true myth. Here's another, perfectly throttling, 1/2A engine http://www.youtube.com/user/hopeso#p/u/17/57WTJUxV0DM that one being a DIESEL engine as well as being 1/2A.
Two: Diesel engines will not run without ether in the mix. Diesel engines WILL run without ether in the mix with several makes of diesel engines, traditional, such as the PAW http://www.youtube.com/user/hopeso#p/u/64/MfH8j_NBvRE and modern such as the MP Jets http://www.youtube.com/user/hopeso#p/u/69/E8_aLl_eAzI What diesel engines WON'T do is START without ether in the mix. Ether raises the cetane level a great deal and allows for a lower compression setting to affect a HAND start. However, if you use an electric starter, that will turn the engine over with higher piston speeds resulting in better compression seal and improved starting characteristics.
Here, we have the epitome of a model, diesel engine running on a no ether fuel. http://www.youtube.com/user/hopeso#p/u/42/PgxIywcu7UQ It's a Norvel .15 and it's running on B100, Biodiesel. No ether and no oil either, despite being a two stroke. It was a real *%$#* to get started but with a high ether PRIME and a starter and a dozen, prime runs, she finally lit off and kept running.
These are two, LONG held myths that I took the time to disprove, instead of just arguing about them.
11-26-2010, 08:37 AM
#524
Join Date: Jul 2006
Location: Portageville,
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RE: Downwind turn Myth
Sorry lnewqton you are right I did get you confused as well as the side of my ias to I did have it backward thi ias is higher on the upwind side and slower on the downwind side of the pass, Its been a couple of weeks since i've flown the thing, but the ias is different depending on if i'm upwind or downwind. for everyone else take the information and use it how you feel fit, either use it to learn or be puzzled or you can flame me act childish if thats what you need to lift your spirits up, im done with this, everyone has their theories and ideas and I don't think anyone has even considered changing their mind so the discussion is pointless. happy black friday and have a good xmas, time to go get the shop ready to work on the full size model 12 and finish my .60 gp extra
11-26-2010, 08:50 AM
#525
RE: Downwind turn Myth
ORIGINAL: AndyW
The downwind turn is not a factor at altitude. But it IS near the ground.
The downwind turn is not a factor at altitude. But it IS near the ground.
I've been actively flying GA aircraft since '87 so I'd like to ask you.. at what AGL altitude, say 10 kts above MCA is the 'turn' NOT a factor?????
