HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Sep 07, 2012, 01:45 AM
Augernaut
Wookster's Avatar
United States, KS, Overland Park
Joined Jan 2010
1,466 Posts
Quote:
Originally Posted by kaptondave View Post
If that is what you got from that your reading comprehension is somewhat lacking.
Almost as lacking as your sense of humor.
Wookster is offline Find More Posts by Wookster
Reply With Quote
Sign up now
to remove ads between posts
Old Sep 07, 2012, 05:04 AM
Registered User
Toowoomba, QLD, AUSTRALIA
Joined Jan 2008
617 Posts
Yeah, I'm definitely more comfortable turning away from myself in circuits than turning towards and tend to prefer doing certain things either left-to-right or right-to-left, but flying pattern means I don't often have the luxuary to chose which way I have to do something.

Flying pattern also means I have to fly referenced to the ground so my airspeed is all over the place trying to maintain that "constant speed" look.
bjr_93tz is offline Find More Posts by bjr_93tz
Reply With Quote
Old Sep 07, 2012, 10:57 AM
Thailand
Joined Aug 2010
527 Posts
Wookster, I agree with you. I came to the same conclusion.
As for the flying inside an all glass Antonov, I'm baffled.
Free flight models are good examples of what really happens on a windy day.
The circuit is elongated and the model blows away but they maintain a constant air speed even though they appear to nearly stop into wind and go quickly down wind relative to the ground.
Jim
Fox-composites is offline Find More Posts by Fox-composites
Reply With Quote
Old Sep 07, 2012, 07:33 PM
Tossing planes into the snow
Canada, BC, Smithers
Joined Nov 2011
3,150 Posts
Flying a Vapor inside an Antonov, glass or not, is the same as flying a Vapor inside a building or outside on a calm day. That is because the air is moving at the same speed as the pilot. That analogy has nothing to do with a downwind turn, where the air is moving in relation to the pilot, and he has to adjust for it.

As stated by Fox-composites, free flight models fly just like birds soaring in circles on a windy day. From our stationary perspective on the ground, it looks like they almost stop moving upwind and speed up on the downwind leg. Because we have no way of interfering with the flight of the plane, a constant air-speed is maintained.
Jovanx is offline Find More Posts by Jovanx
Reply With Quote
Old Sep 07, 2012, 08:16 PM
Space power
cfircav8r's Avatar
United States, IA, Hampton
Joined May 2012
313 Posts
The point is the pilot needs to adjust for ground track and not speed. If you are going too fast, down wind, turn earlier instead of slowing down and possibly stalling. The problems are with inapropriate actions due to mistaken perceptions, not the wind itself. Any increased possibility of stall is the same, no matter what phase of flight, whenever we fly in wind.
cfircav8r is online now Find More Posts by cfircav8r
Reply With Quote
Old Sep 07, 2012, 09:10 PM
Thailand
Joined Aug 2010
527 Posts
All we need is someone who has on board monitoring equipment.
It would need to be an on board pitot tube sensor that can record the airspeed.
GPS would be useless as it only measures ground speed..
Then they would pick a fairly windy day and fly straight upwind, do a tight turn and fly straight downwind. Then after maybe 5 seconds do the same turn back into wind and see if there is any variation in the recorded airspeed.
I think there would be.
Jim
Fox-composites is offline Find More Posts by Fox-composites
Reply With Quote
Old Sep 07, 2012, 09:40 PM
3D? I only got two thumbs!
United States, MA
Joined Jul 2012
1,480 Posts
Quote:
Originally Posted by Fox-composites View Post
All we need is someone who has on board monitoring equipment.
It would need to be an on board pitot tube sensor that can record the airspeed.
GPS would be useless as it only measures ground speed..
Then they would pick a fairly windy day and fly straight upwind, do a tight turn and fly straight downwind. Then after maybe 5 seconds do the same turn back into wind and see if there is any variation in the recorded airspeed.
I think there would be.
Jim
That would be a good experimental way to prove that there is not a variation in the recorded airspeed. But the rule has to be hands off the left stick entirely - no subconscious fussing with the throttle. And constant altitude. And the other thing is the experiment needs to be repeated on a calm day just to see what kind of inherent variation there is due to factors beyond control, like for example battery voltage, difficulty in maintaining constant altitude, etc. And ideally several trial runs both on calm and on windy days.

- Ken
AeroKen is online now Find More Posts by AeroKen
Reply With Quote
Old Sep 07, 2012, 10:57 PM
Space power
cfircav8r's Avatar
United States, IA, Hampton
Joined May 2012
313 Posts
Iv'e done that many times in full scale airplanes. Models are no different. I can maintain the same altitude, throttle setting and bank angle and the airspeed will show the same drop depending on bank angle but will not vary depending on wind direction or speed.
cfircav8r is online now Find More Posts by cfircav8r
Reply With Quote
Old Sep 08, 2012, 12:21 AM
Augernaut
Wookster's Avatar
United States, KS, Overland Park
Joined Jan 2010
1,466 Posts
Quote:
Originally Posted by cfircav8r View Post
Iv'e done that many times in full scale airplanes. Models are no different. I can maintain the same altitude, throttle setting and bank angle and the airspeed will show the same drop depending on bank angle but will not vary depending on wind direction or speed.
But, can you do that within a set boundary in a 60MPH wind? things get a little funny when you scale them down. Not saying you are wrong, I'm just curious with all this discussion if scaling plays a small part in all of this. Almost all RC pilots are limited by visial range and more often than not physical boundaries thier aircraft cannot pass. So what would you experience in a full scale aircraft if for instance you were flying over a nascar oval track. If you had to keep your aircraft directly over the track and run that pattern, would the downwind leg present any unique challanges? Or if in a 60 mph wind you had to trace a perfect circle on your gps map? A lot of folks want to separate the ground from the equation, but in all reality, especially in the RC world. Terra Firma is what we all are dominated by.
Wookster is offline Find More Posts by Wookster
Reply With Quote
Old Sep 08, 2012, 01:12 AM
Space power
cfircav8r's Avatar
United States, IA, Hampton
Joined May 2012
313 Posts
Yes we are trained to fly in reference to the ground adjusting for the wind at pattern altitude. I have done S-turns across a road, turns about a point (perfect circle) and rectangular course (confined area) in as high as 45 kt winds (that's about 51mph.) This drives home the danger of attempting to maintain ground track, because on the down wind turns you have to have the steepest bank angle which will cause the most reduction in airspeed and the highest increase in stall speed due to load factor increase. This is all due to the pilots desire to maintain ground track and not the winds affect on the aerodynamics. Blaming the wind would be like blaming a car for making you stall because it was going to slow while you were attempting to match its speed.
cfircav8r is online now Find More Posts by cfircav8r
Reply With Quote
Old Sep 08, 2012, 02:07 AM
Augernaut
Wookster's Avatar
United States, KS, Overland Park
Joined Jan 2010
1,466 Posts
Quote:
Originally Posted by cfircav8r View Post
Yes we are trained to fly in reference to the ground adjusting for the wind at pattern altitude. I have done S-turns across a road, turns about a point (perfect circle) and rectangular course (confined area) in as high as 45 kt winds (that's about 51mph.) This drives home the danger of attempting to maintain ground track, because on the down wind turns you have to have the steepest bank angle which will cause the most reduction in airspeed and the highest increase in stall speed due to load factor increase. This is all due to the pilots desire to maintain ground track and not the winds affect on the aerodynamics. Blaming the wind would be like blaming a car for making you stall because it was going to slow while you were attempting to match its speed.
So in reality, In RC there is a factor to a downwind turn. Mainly because with the pilot being on the ground, there is no way to eliminate ground track. I certainly see that there is no difference on the aerodynamic affect of wind, but more a situation where in order to maintain relative position to the ground. The aircraft is sometimes pushed beyond its flight envelope thanks to the wind. If what I am reading is corect, both sides of this argument are correct. It's just difficult to explain exactly what it is that is being experienced in the air.
Wookster is offline Find More Posts by Wookster
Reply With Quote
Old Sep 08, 2012, 02:29 AM
Space power
cfircav8r's Avatar
United States, IA, Hampton
Joined May 2012
313 Posts
The fact that people have difficulty is correct but to say that the wind pushed them or they couldn't accelerate enough to keep up with the wind is false. With the understanding that it is a control issue and not an aerodynamic issue you will be better prepared to compensate correctly. You will find you are able to do more in the wind if you understand it, where others are just limited. I have no problems flying in the wind and find it amusing to do things that aren't possible without wind, such as land backwards.
cfircav8r is online now Find More Posts by cfircav8r
Reply With Quote
Old Sep 08, 2012, 02:43 AM
Augernaut
Wookster's Avatar
United States, KS, Overland Park
Joined Jan 2010
1,466 Posts
Quote:
Originally Posted by cfircav8r View Post
The fact that people have difficulty is correct but to say that the wind pushed them or they couldn't accelerate enough to keep up with the wind is false. With the understanding that it is a control issue and not an aerodynamic issue you will be better prepared to compensate correctly. You will find you are able to do more in the wind if you understand it, where others are just limited. I have no problems flying in the wind and find it amusing to do things that aren't possible without wind, such as land backwards.
Agreed, I almost get the feeling that more so than a lack of understanding is a lack of proper teminology. You can get into the fine details of exactly how ground tracking caused you to exceed the flight envelope and put yourself into a high speed stall right before the runway on a windy day. Or most likely you will just say " down wind turn" as you grab a trash bag and start walking to your model remnants. I have no experience in full scale flight. I can only dream of that, but I at least seem to have a decent comprehension of how the wind will influence my model. I'm six and a half feet tall, and my club calls me "micro Steve" because the wind can be gusting at 30 MPH, and i'll be out there with my Micro birds. So while the wind is not to blame for the crash, there is something to making a downwind turn to final in an RC model. Especially when that model is the size of your hand. I've done an entire curcuit without ever changing my heading more than 20 degrees. Then again it was the UMX beast, so it was kinda cheating.
Wookster is offline Find More Posts by Wookster
Last edited by Wookster; Sep 08, 2012 at 02:49 AM.
Reply With Quote
Old Sep 08, 2012, 08:34 AM
Tossing planes into the snow
Canada, BC, Smithers
Joined Nov 2011
3,150 Posts
Quote:
Originally Posted by Wookster View Post
If what I am reading is corect, both sides of this argument are correct.
I agree, and that was the assumption I made when starting this thread. Both sides agree that wind should have no effect unless taking off, landing, or navigating. Nobody ever has trouble with a downwind turn when they are high off the ground, but only when they are low and are thinking about landing. Maybe we should call it the "low-level downwind turn".

What surprised me is all the responses from pilots of full-scale planes. I was under the impression that the problem was unique to RC pilots, who are standing still while both the air and the plane are moving. It puts a new perspective on this phenomenon to hear it also affects pilots who are in the plane.
Jovanx is offline Find More Posts by Jovanx
Reply With Quote
Old Sep 08, 2012, 08:57 AM
Space power
cfircav8r's Avatar
United States, IA, Hampton
Joined May 2012
313 Posts
That is because even pilots in the plane use the ground as reference, and fall into the trap of relying on their perception and not their instruments. It has gotten more than a few pilots killed. You will find very few instrument rated pilots that still don't understand the phenomena.
cfircav8r is online now Find More Posts by cfircav8r
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Astro Flight 109 Facts or Fiction. everydayflyer Batteries and Chargers 12 Jan 22, 2005 12:27 PM
Stock: Fact or Fiction..... Geoffrey109 Micro Helis 0 Nov 26, 2004 10:26 PM
Razor Fact Or Fiction? mike3976 Power Systems 9 Oct 26, 2003 06:12 PM
LI-PO Fact or Fiction? gbruce Electric Ducted Fan Jet Talk 4 Oct 24, 2002 02:48 PM
Kyosho F16, Fact or Fiction? stuart warne Electric Ducted Fan Jet Talk 20 May 31, 2002 01:49 AM