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May 25, 2019, 05:05 AM
Bye Bye VP Aug 2010 - Aug 2012
Gerry__'s Avatar
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Basic Physics


I think that too often beginners either assume they know enough or just can't be bothered with physics.

This is from a British Model Aeronautical Society pamphlet.

Quote:
BRIEFING 3 - THE EFFECT OF WIND ON THE AIRCRAFT IN FLIGHT

There is probably more nonsense talked and written on this subject than any other connected with the practical side of flying! In reality, the matter is very simple - it is just that so many people find it hard to accept.

Provided that your flying area is clear of vertical obstructions (houses, trees, hedges, hangers etc.) the wind will blow fairly steadily from a constant direction once the aircraft is above about 50ft. Below this height, and depending on the surface of your flying site and the proximity of obstructions, there will be some turbulence both vertical and lateral.

Once you understand this principle you will see that a turn from an into wind heading to crosswind will appear to be a fairly sharp turn when seen from the ground and a turn from downwind to crosswind will appear to be slow and elongated. You must accept these visual effects for what they are and remember at all times that if you have not altered your throttle setting and the aircraft is at constant height then your airspeed is constant and the aircraft is in no danger of stalling.

Once the aircraft has climbed out of this turbulent level it is, in effect, flying in a steadily-moving block of air. Thus, with a windspeed of 10 mph the block of air in which your aircraft is flying is moving downwind at a speed of 10 mph. So, your aircraft which flies at a speed of, say 20 mph will appear to be doing only 10 mph when flying into the wind (flying speed less windspeed) and 30 mph when flying downwind (flying speed plus windspeed). In point of fact your aircraft knows nothing about the windspeed at all and is flying at a steady 20 mph all the time!

You will often hear people say that their aircraft tends to climb when turning into wind and dive when turning downwind. What is really happening, of course, is that they are subconsciously trying to compensate for the apparent variation in speed and themselves causing the aircraft to climb and dive.

One major point to remember - don’t try to keep your apparent speed constant or you will find that you will have your aircraft at full throttle when going into wind and stalling when it goes downwind.

If you find all this difficult to visualise, try to imagine yourself piloting a model boat from the bank of a fast-flowing river. In this situation you will find that you can understand the problems outlined above.

When flying in a wind of any strength you will find that your model can be carried away from you very quickly when it is travelling downwind. It is essential not to let it go too far. If you do, not only do you stand a good chance of losing control because you just can’t see the aircraft properly, but it is a long and slow slog back to your position against the full strength of the wind. There is another major factor - if your engine stops it will be difficult or impossible to glide the aircraft back to your position if it is too far downwind.

So always try to keep your aircraft upwind of your position as much as possible. By doing so you will save yourself from falling into some very difficult situations.
If you're starting out then I highly recommend you read this and I promise you, you will crash less if you understand what it teaches.
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May 25, 2019, 08:52 AM
Registered User
Just like always rowing upriver first so you aren't too tired to get back home
May 25, 2019, 11:16 AM
yank and bank!!
Thats very good information......


I don't know if they have a pamphlet on the height of watertight doors in unsinkable cruise liners, butttttttt........
May 25, 2019, 12:47 PM
AeroDan
Is the rest of the pamphlet available? GREAT tip!!!
May 25, 2019, 02:35 PM
Bombs away! Err...landing
Ira NZ's Avatar
Ahhh...Flying in the wind...Downwind stall...Whatever you want to call it. Always a great way to start an argument, along with the airplane on a treadmill.
May 25, 2019, 03:28 PM
Going back to balsa

Basic Physics


Reminds me of this:

https://en.wikipedia.org/wiki/Blackbird_(land_yacht)
Blackbird (land yacht)

I lost a $100 bet with Rick Cavallaro on that one.
May 25, 2019, 04:29 PM
Closed Account
Quote:
Originally Posted by Ira NZ
Always a great way to start an argument, along with the airplane on a treadmill.
But what about an airplane on a treadmill, with the wind blowing...

...From the top down...
May 26, 2019, 01:26 AM
Bye Bye VP Aug 2010 - Aug 2012
Gerry__'s Avatar
Thread OP
Quote:
Originally Posted by Ira NZ
Ahhh...Flying in the wind...Downwind stall...Whatever you want to call it. Always a great way to start an argument, along with the airplane on a treadmill.
People who don’t know what they’re talking about is the problem:

Quote:
Originally Posted by Rampage
The steady headwind is all it needs to continue to create lift and therefore fly.

The determining factor here is how long the pilot can continue to fly the aircraft as it's groundspeed takes it out of visual range.

A glider in a steady headwind capable of keeping it aloft, while being controlled in a manner that prevents it from turning downwind or otherwise crashing, can stay aloft until it's receiver battery dies and that control is lost.

It's essentially a kite without a string, and kits don't need motors. They also generally don't have airfoils. All they need is angle-of-attack and a headwind and they can stay there indefinitely.
May 26, 2019, 09:16 AM
Registered User
Grup's Avatar
May 26, 2019, 09:43 AM
Registered User
Quote:
Originally Posted by Rampage
The steady headwind is all it needs to continue to create lift and therefore fly....
If only somebody could write an app that could tell if a post is a troll or supposed to be taken seriously.
May 26, 2019, 11:26 AM
Bye Bye VP Aug 2010 - Aug 2012
Gerry__'s Avatar
Thread OP
Quote:
Originally Posted by jkettu
If only somebody could write an app that could tell if a post is a troll or supposed to be taken seriously.
Oh, he believed in what he was saying.
May 26, 2019, 01:36 PM
IMO ( In My Opinion ) →
balsa or carbon's Avatar
Quote:
Originally Posted by Gerry__
I think that too often beginners either assume they know enough or just can't be bothered with physics.

This is from a British Model Aeronautical Society pamphlet.



If you're starting out then I highly recommend you read this and I promise you, you will crash less if you understand what it teaches.
I always recommend that unassisted beginners attempt their first few flights in no wind ( or very little wind ) . In most places , the best chance for no wind is at sun-up . Unfortunately : very few people are willing to get up that early , and end up attempting their first flights in wind ..... which often ends up in a crashed or lost plane .
May 26, 2019, 03:09 PM
Bye Bye VP Aug 2010 - Aug 2012
Gerry__'s Avatar
Thread OP
Quote:
Originally Posted by balsa or carbon
I always recommend that unassisted beginners attempt their first few flights in no wind ( or very little wind ) . In most places , the best chance for no wind is at sun-up . Unfortunately : very few people are willing to get up that early , and end up attempting their first flights in wind ..... which often ends up in a crashed or lost plane .
Knowledge is power but most people are stupid.
May 26, 2019, 03:25 PM
Bye Bye VP Aug 2010 - Aug 2012
Gerry__'s Avatar
Thread OP
Quote:
Originally Posted by NC14310
But what about an airplane on a treadmill, with the wind blowing...

...From the top down...
What are the chances of such scientifically accurate information being made a sticky? Or is it still too controversial, after 100+ years of flight?
May 26, 2019, 04:31 PM
IMO ( In My Opinion ) →
balsa or carbon's Avatar
Quote:
Originally Posted by Gerry__
Knowledge is power but most people are stupid.
Do you mean ignorant ?


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