Yes indeed. [8D]

<div style="margin: 0in 0in 0pt"><span style="font-size: larger">Good job Brad, while highhourse is correct, it is not complete. Your post finished it. This problem with acceleration in the big planes (like the B-52)
can take some time. Even with our RC's on very windy days, you can see the acceleration when you yank it down wind. It does take time though.

A 200 ton object can not instantly go from 200mph to 220mph through a space, there is time involved.
Likewise turning into the wind does not magically dissipate the inertia,, it takes some time.</span></div><span style="font-size: larger">


Tim

</span>

I'm sorry but what "new airflow" are you referring to? Gusting? In a steady wind there is only one airflow. When you change direction the inertia is seen in the different ground speeds. The speed changes you are referencing is relatable to ground speed not airspeed. If you want to maintain groundspeed then yes what you are saying is true, but air speed is in relation to the airmass and not the ground. The inertial changes seen at the A/C are the same with wind or without. These are acted upon by the turning componant of lift and are counteracted by the increased drag. when you add wind the inertia from the wind direction is directly translated into ground speed. When you go from a 20 knot tail wind to a 20 knot head wind you have a 40 knot reduction in ground speed, that is the inertia you keep referencing.

Where did you get the "instantly" from?

If, in still air, a 200 ton aircraft flying at 200mph does a 180 degree steep turn without adding power, it will take about 40 seconds or so to complete the turn...and the plane will lose speed in the turn due to the fact that the wing loading will be higher. So, at the completion of the turn, the plane's airspeed will have decreased to, let's say, 185 mph. When the plane is back in straight and level flight it will accelerate back up to 200mph...without touching the throttles.

Same situation except with a 50mph headwind before beginning the turn. The plane's air speeds will remain the same as in the previous example throughout the maneuver. The ground speeds, however, will be...beginning of turn=150mph. At the completion of the turn...235mph (185mph + 50mph on the tail). Without touching the throttle the plane will re-accelerate to 200mph airspeed and, of course, the ground speed will be 250mph.

The people in the aircraft will see no difference in the airspeeds with or without the presence of wind.

C'mon guys....I'm the one who has been saying we CAN'T instantly accelerate (rotating Earth examples, etc.). And so we see the effects of that impossibility on our models as they turn DW. One more try, then bedtime:

Your model is capable of 100mph AS and headed right-to-left in a left-to-right, 100mph, steady wind. IOWs, it's hovering from your POV on the ground. Now you quickly turn it DW. In order to not lose lift, it somehow would have to turn and accelerate instantly to 200mph, now going from your left to right, so as to have an AS of 100mph. Instantly....and if it couldn't do that, then it would drop as it went from a 100mph tailwind, struggled through an AS of zero for a moment, until finally catching up and exceeding the 100mph 'sea of air' by 100mph in order to regain its 100 AS.

Where is the above reasoning flawed?

Great fun(!)....tomorrow, then.

Ray<br type="_moz" />

Hang in there, Don![8D]

I don't want to get into a rant about quals, but I will say that I've taught folks to fly "by the numbers" for years (OK, decades...), and it works, in RC and full-scale. Use a given throttle setting on downwind (half, third, whatever works) and make shallow banks (RC=safe, full-size=no spilled drinks/screaming). Don't touch throttle again, but manage energy, drag, etc., to get to the runway. Adding power (or snap/spin/crash) is disqualifying, try again. Again, this is a steady-state discussion. Gusts/wind shear are managed differently.

Somebody earlier brought up the phenomena of a trainer turning, and upon roll-out gaining altitude. That happens upwind, downwind, no wind, due to "excess lift" (I hate that term) after the turn. Up elevator was being held during the turn, upon roll-out the elevator wasn't reduced at the proper rate so the plane climbs. Happens in full-scale too. Part of that physics/acceleration thing? I dunno, but my head's starting to hurt...

Another f'rinstance: landing/taking off at higher-elevation fields. When landing, the sensation of the ground rushing by (perception) is unreal, seems like you're still at cruise. The desire is to reduce throttle to make the "sight picture" look right. Indicated airspeed says you're OK, so don't touch throttle, but one uses a LOT more runway at higher elevation/density altitude. Hence tire speed and weight limits in such cases.

While the fundamental premise is correct, the aircraft is flowing with the environment and it could care less, and the person on ground has vision cues that may be misleading, there is defineately something that happens to a plane when turning in wind.  There is that moment, or two, and I think its more pronounced with certain configurations, where the airplane flying status is vulnerable to stall and crash.  If you've ever flown a basic .40 trainer on a windy day, say 20-30mph wind, as you head into the wind and pull a loop, as you get on the top side and are inverted and heading downwind, the controls get sloppy and the plane may even flounder in the air until it starts flying again.  My favorite flying is in the wind, the more windy it is the more likely I'm gonna get to the field, put on dirt-bike goggles to block the dust,  and put something up.  My record is 40mph w/ 60mph gust w a .40 sport plane, have done almost that much w/ a .90 heli too, the only problem w/ the heli is trying to land w/ the rotor disc at a 45 degree angle to the ground... need to level it just as you cut the power and stick it to the ground.  Aside from theorems and laws there is a personal and significant thing happening at that moment.

Anyways, happy flying.[8D]

Define 'quickly' (rate). I think the aero pilots (FS) here have the best handle on this, as they pilot craft that most closely approximate our RC stuff. As they've already pointed out, the downwind turn thing is a myth.

Did anyone else see the Mythbusters episode on this, where they drug a canvas under an ultralight/LSA type and came to the WRONG conclusion? it got airborne, but the pilot was adding power and started moving forward (a DQ IMO).

Gents

I am finished with my input, for me no problems.
The next you have to prove yourself, I doubt!

Cees

I have seen a couple of incorrect conclusions by them.

This is all very true,, I was just trying get the time point across. My powered parachute might show this the best because of the low airspeed (30mph).
If I turn down wind fast, (15mph wind) , it takes some time for the craft to get to the new 30mph airspeed (45mph ground speed) and I can loose
50 feet or so. We fly at 50 feet a lot so it isvery important to us. note: we make level turns in 0 wind, but it is hard to do in 15mph winds. Of course this
would never be felt in a 300,000lb jet going 300kts.

Tim

Right on, that's what I'm talking about TimT2000.  My worst experience w/ this was 20 yr ago was a ST .45 powered high wing float plane, lots of drag, did a slow speed loop into the wind (no problems of calm days) and as it hit top of loop going downwind it just started falling, one would think 300' would be plenty of altitude to get airflow going again, one would be wrong.

You are flying 100mph (airspeed) before you start your turn and are flying 100mph (airspeed,) - the speed lost due to increased drag from the turn, when you get down wind. The ground speed is accelerating through the turn. At 90 degs. it will be 100mph at 180 it will be 200mph, - the lost speed from the turn. The ground speed will increase constantly as the turn is made. That is your inertia. Do some reading, go ask a professor at a major college, take some ground school from a part 141 flight school. Any one of these would be better then using some long ago physics classes and anecdotal evidence reasoned out at the flying field. The whole models are different then full scale is a load. NASA would not have wasted decades of research on wind tunnel models if that were the case.

We need to debunk a few other things mentioned in this thread too.  Mr Doolittle is an overinflated piece of american folklore and I give him little credit in this discussion, and Stephen Hawking is a fraud.  Anyways, happy flying.[8D]

Your post failed. Thanks for trying your best, take care.

LOL!! That "overinflated piece of American folklore" successfully raced the GeeBee Super Sportster and won with it in the 1930s. Pylon turns and the wind haven't changed in the last 80 years.

I just watched the video and have a few thoughts.

First off, the flying I saw on the entire video gave me the impression that the jet was really being "man handled", or flown quite roughly (sticks being banged around instead of smooth inputs). It could have been just a bad radio set up with too much deflection and not enough expo, but the video in my opinion leads to the drawing one of these conclusions.

2nd, the crash was probably the result of too little airspeed entering the maneuver for the amount of G put on the wing. The wing stalled and the jet entered a spin/spiral. The pilot never relaxed the flight controls long enough for the jet to recover and gain sufficient airspeed before excessive elevator was reintroduced and the jet stalled/spun again, this time all the way to the ground.

No matter what, it sucks...sorry you lost a good looking jet.

I have done the same thing in the past so I feel for you.

Beave

Don't know about you guys but my GAinstructor would have kicked my butt if I let the airspeed or altitude bleed off in a turn.

So maybe this is all a myth...lol

Tim

Just ignore the "Doolittle Troll", my brothers.

Just let it go.

Wind or no wind...planes lose airspeed in turns unless power is added. Not relevant in this thread.

Wrong thread. Stay on the topic please so as not not derail this one.

Dooh![&:]

Easy mistake, they are seperate but related :-)

I have followed both all day......

If you were told to maintain altitude and throttle setting how would you maintain airspeed? Only an idiot would expect you to jockey the throttle for every turn, especially if you are flying IFR. Making you maintain airspeed and altitude throughout the flight is an attempt to teach you to stay aware of what the plane is doing, but it needs to be tempered with the knowledge that a smooth flight for your passengers is also important. An instructor that was trained to 141 standards and is training to them as well, is going to train you to be smooth and precise. Airspeed can fluctuate with turns and turbulence and fighting it constantly is a surefire way to get your passengers sick. A 30deg bank you will loose about 2-3 knots through a 180deg turn in a Cessna 152. It will recover it as soon as you are wings level, but you still loose a little. If you were to enter a 60deg bank in a Cessna 152 fully loaded and he expected you to maintain airspeed and altitude then you go full throttle and hope its not too high a pressure altitude. If you loose airspeed but maintain altitude and he's mad, then again, he's an idiot.