ORIGINAL: HarryC
ORIGINAL: Art ARRO
Harry C,
The technique described in the JPO Knowledge Bank should have stated ''relative ground speed'' rather than '' relative airspeed'' when landing a jet model in the wind. Thanks for pointing this out and corrections will be made to the article. Good catch.
Art ARRO
Hi Art,
That will just get you into a bigger mess! Let’s do that straight substitution and see how it reads.
the jet will lose relative ground speed when turning downwind ……
When turning base to final into a strong headwind, relative ground speed will actually increase
Well clearly that’s wrong, a plane gains, not loses ground speed when downwind, and vice versa when turning into wind.
Ok, let’s keep that substitution and correct the groundspeed
For instance, if a 10-mph crosswind is blowing at you across the runway the jet will gain relative ground speed when turning downwind to base and bit more power will be required to avoid a stall. When turning base to final into a strong headwind, relative ground speed will actually decrease and the jet may level off or even climb a bit. Compensate with a throttle adjustment.
Again, its complete nonsense. The article now says that the plane gains groundspeed when down wind, so it may stall and you should increase throttle?!! It loses groundspeed when into wind so it climbs and you should reduce throttle?!!!!!
Sorry Art but there is no escaping the fact that whoever wrote the article really did mean exactly what he wrote but doesn’t understand the physics of flying in a wind. The only safe thing to do is to remove that paragraph entirely. Wind has no effect on airspeed in a turn, and changes in groundspeed have no effect on handling.
As can be seen from many posts above, many people want to copy such articles into their club newsletters. So it is important not to publish articles which contain basic errors of physics and recommend incorrect piloting!
Harry,
We've been down this road before,with the "downwind turn myth" thread. You saying it's all nonsense,is nonsense. Your statement "Wind has no effect on airspeed in a turn, and changes in groundspeed have no effect on handling",while tehnically true,is overly simplistic,and misleading.
The intent is to make the newbie aware that visually perceived speed will change significantly,at a constant airspeed,when changing course in a strong wind.That is a huge point. If he flies the airplane at a comfortable buffer above stall speed into a 20 kt headwind,then turns downwind,the groundspeed,and more importantly perceived speed, will be 40 kts faster,if he doesn't change pitch/power. An inexperienced pilot may incorrectly perceive that the airspeed is increasing,and make the improper input of decreasing power/increasing pitch,leading to a stall,and departure from controlled flight.I have seen it happen more than once.
You,and others have argued the semantics of this,yet it continues to be a problem for newer pilots.It may not be explained exactly correctly on the JPO sight,but at least the attempt is being made to enlighten newbies that there are extra considerations when operating in stronger winds.I applaud that effort.
Erik