[NSRCA-discussion] Steady Wind

ronlock at comcast.net ronlock at comcast.net
Mon Oct 15 05:25:16 AKDT 2007 

Yes !!
Ron Lockhart
(PS   - you could substitute a hot air balloon as place where RC pilot is standing for the aircraft carrier, and have same situation)

-------------- Original message -------------- 
From: <vanputte at cox.net> 

> The best analysis of the effects of a steady wind was published by a South 
> African named Len Salter 25-30 years ago. He wrote that all you need to 
> understand what's really going on is an aircraft carrier steaming downwind at 
> the same speed as the wind. You stand on the carrier's deck and there's NO 
> wind. You fly your airplane and it flies just as it would on a calm day. You 
> loops are nice and round and you get perfect verticals by pointing the airplane 
> straight up or down. There's no dreaded "downwind turn" problem. 
> 
> Now suppose you were instantaneously teleported to an adjacent island. Your 
> airplane would have no clue that you weren't still on the carrier's deck, but 
> I'll bet your airplane would "fly dfferently". 
> 
> Ron 
> 
> ---- Mark Atwood wrote: 
> > George, 
> > 
> > I think Ron¹s point is that the ³moving pool² IS the same...except the 
> water 
> > is not moving relative to the pool. The water is moving just as fast if the 
> > giant (I can¹t believe you guys have sucked me into this conversation or 
> > worse, this analogy) was running down the street with the pool, as it would 
> > be if there was a river..it¹s just that the walls of the pool are moving 
> > with it. 
> > 
> > If the pool was SO big, that there was no frame of reference...the water 
> > could be flowing at any speed and you would never know...(until you finally 
> > got close to a side :) 
> > 
> > -M 
> > 
> > 
> > On 10/14/07 1:33 PM, "george w. kennie" wrote: 
> > 
> > > Ahaaaa ! .................for the first time in all these years I understand 
> > > the reasoning of my good friend Ron Lockhart with his swimming pool analogy, 
> > > but,........there's a fly in the ointment !!!!!!!!!!!! 
> > > Someone, maybe Nat, mentioned that air is a fluid. I agree ! Moving air is 
> a 
> > > CURRENT ! In order for the swimming pool analogy to equate to our situation 
> > > of flying in a crosswind, the pool would need to be converted into a hot tub 
> > > with jets located all down one side and exhaust outlets on the other side so 
> > > that a cross CURRENT could be established (same as the crossing CURRENT 
> we're 
> > > flying in ) whereupon the swimmer would then be pushed to the exhaust side 
> of 
> > > the pool. He would certainly feel the force of the current exerting a 
> > > deleterious effect on his intended swimming direction and would have to 
> > > compensate and if he was in a boat with a rudder (with forward propulsion) 
> he 
> > > would aquavane vectorially due to the combined effect of the CURRENT and the 
> > > forward propulsion. It will not make any difference whether you pick the 
> pool 
> > > up and move it sideways, fore or aft, turn it around, raise it, or lower it 
> as 
> > > long as the AC doesn't go out. :>) 
> > > Who else,...me 
> > > 
> > > 
> > > 
> > >> 
> > >> ----- Original Message ----- 
> > >> 
> > >> From: Ron Lockhart 
> > >> 
> > >> To: NSRCA Mailing List 
> > >> 
> > >> Sent: Saturday, October 13, 2007 10:46 PM 
> > >> 
> > >> Subject: Re: [NSRCA-discussion] (no subject) 
> > >> 
> > >> 
> > >> 
> > >> See comments at end of RJO post. 
> > >> 
> > >>> 
> > >>> ----- Original Message ----- 
> > >>> 
> > >>> From: rjo626 at aol.com 
> > >>> 
> > >>> To: nsrca-discussion at lists.nsrca.org 
> > >>> 
> > >>> Sent: Saturday, October 13, 2007 4:55 PM 
> > >>> 
> > >>> Subject: [NSRCA-discussion] (no subject) 
> > >>> 
> > >>> 
> > >>> 
> > >>> The 010 track 
> > >>> is caused not by a weathervane effect, but by the body of air moving from 
> > >>> west to east while airplane progresses 
> > >>> through it on north heading. 
> > >>> 
> > >>> During this flight, (and in 
> > >>> Case 1 and 2) a yaw string would be straight, no wind hits side of 
> > >>> airplane. 
> > >>> 
> > >>> I'm missing something here. The body of air moving from west to east is 
> > >>> not hitting the airplane? Then what makes it go off course? Please 
> > >>> explain. 
> > >>> RJO 
> > >>> 
> > >>> Comments- 
> > >>> 
> > >>> The airplane is carried along in the west to east movement of the body of 
> > >>> air. 
> > >>> 
> > >>> Sort like swiming in north direction in a swimming pool. And a big 
> giant 
> > >>> (wind) picked up the pool 
> > >>> 
> > >>> and carried it in a west to east direction. You would wind up going west 
> > >>> to east, but would not 
> > >>> 
> > >>> have been hit on your west side by water. You would still be swimming 
> > >>> north, so you would travel 
> > >>> 
> > >>> north on account of your swimming (airplane airspeed) and at the same 
> time 
> > >>> be carried east by 
> > >>> 
> > >>> by the giant (wind) 
> > >>> 
> > >>> 
> > >>> 
> > >>> Another way of looking at it - a non powered balloon in the same body of 
> > >>> air will be carried in the same west to east direction, and same speed as 
> > >>> the wind. If you were riding in the balloon, you would feel zero wind, 
> > >>> cause balloon is not moving in the body of air. Your direction of 
> movement 
> > >>> over the ground will be same direction and speed as the wind. 
> > >>> 
> > >>> If balloon had a yaw string, it would point straight down, same as it 
> would 
> > >>> if in no wind air, which means it would not 
> > >>> 
> > >>> be moving over ground. 
> > >>> 
> > >>> 
> > >>> 
> > >>> This "wind doesn't hit the side of the airplane" discussion ignors 
> gusting 
> > >>> wind, random turbulence, etc. that might momentarily "hit" the plane and 
> > >>> cause changes in heading, pitch and airspeed. They are relatively short 
> > >>> duration. 
> > >>> 
> > >>> 
> > >>> 
> > >>> Later, Ron Lockhart 
> > >>> 
> > >>> 
> > >>> 
> > >>> 
> > >>> 
> > >>> Email and AIM finally together. You've gotta check out free AOL Mail 
> > >>> 
> > > >>> OLAOF00020000000970> ! 
> > >>> 
> > >>> 
> > >>> 
> > >>> 
> > >>> 
> > >>> 
> > >>> _______________________________________________ 
> > >>> NSRCA-discussion mailing list 
> > >>> NSRCA-discussion at lists.nsrca.org 
> > >>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion 
> > >> 
> > >> 
> > >> 
> > >> 
> > >> 
> > >> 
> > >> _______________________________________________ 
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> > >> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion 
> > > 
> > > 
> > > _______________________________________________ 
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> > 
> > 
> 
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