Flying in 15 mph winds

[kyleservicetech]

Originally Posted by mred

Well, you did good sitting on the ground, but once you took it up in the air, you blew it. Sitting on the ground and not moving then yes, the air speed changes over the top of the wing just like anything else, but once you get in the air, all that changes. With an airplane flying, it doesn't care what the wind speed is, the AIR SPEED will stay the same. What will change is the ground speed and that has nothing to do with the way an airplane flies, it only has to do with the way it flies over a set course on the ground. If you have a wind speed of 10mph and an airspeed of 20mph, then the ground speed with the wind will be 30mph and 10mph into the wind, but the airspeed is not changing, it is the ground speed that is changing. The air speed stays constant at 20mph. Most new people get all messed up with this and try to slow the plane down while flying down wind thinking that the air speed went up, but only the ground speed went up, the air speed stayed the same.

Flying in turbulence is not fun at all if you are a new person to flying. The air speed is constantly changing due to a fast shift in wind that the plane cannot keep up with and the ups and downs will bounce you all over the place and the lighter the plane the worse it gets. The best time to fly is early morning or late evening when the wind dies down. That doesn't always happen, but most of the time it does.

If you have a good location where there is very little turbulence, then you can fly in more wind, but add turbulence and it changes everything. Best advice is to fly in the early morning or later in the day when the wind dies down.

Ed

Just flew my 150% one kilowatt Electrostreak today at the club field. The field anemometer showed wind was 16 Mph, with gusts to 27 Mph.

Flying was OK, but landing is where the problem shows up. And, you've got to keep the power up, since the wind was gusting between 16 and 27 MPH. If not careful, you can go from flying with a high airspeed, and flying in a stalling configuration in just a few seconds.

[wolfewinde]

Let me try to better understand this

Let's say the plane is flying at 20 MPH straight across a 10 mph wind. Wouldn't airspeed and ground speed both be the same at 20 mph at that point?

Then let's say you make sharp turn into the wind. Wouldn't you still be going 20 mph with an additional 10 mph of wind now flowing over the wings? So wouldn't your effective Airspeed now be 30 mph. Wouldn't you have to slow the plane down to 10 MPH ground speed to maintain a 20 MPH airspeed? = 10 ground speed + 10 windspeed

I could be wrong here - it has been a while LOL

Wolfe

[kyleservicetech]

Originally Posted by wolfewinde

Let me try to better understand this

Let's say the plane is flying at 20 MPH straight across a 10 mph wind. Wouldn't airspeed and ground speed both be the same at 20 mph at that point?

Then let's say you make sharp turn into the wind. Wouldn't you still be going 20 mph with an additional 10 mph of wind now flowing over the wings? So wouldn't your effective Airspeed now be 30 mph. Wouldn't you have to slow the plane down to 10 MPH ground speed to maintain a 20 MPH airspeed? = 10 ground speed + 10 windspeed

I could be wrong here - it has been a while LOL

Wolfe

Nope, got to think about the airplane all by its little lonesome, and forget about the pilot on the ground. As far as the airplane is concerned, if the wind is constant and is not full of gusts, if you set power to fly at 50 mph, that's how fast it will fly, up wind, down wind, side wind, don't matter.

Where the problem is, that model is being controlled by someone standing on the ground, who (hopefully) is not moving. So, if you've got a back yard flyer that flys at 20 mph, and you try flying it into a 20 mph wind, it will stay still, as determined by the pilot, even though its flying at 20 mph. Turn it around, it is now flying downwind at 40 mph, as compared to the pilot. So you've got airspeed that keeps the model flying, and you've got ground speed that can confuse the new pilot as to what's actually going on.

So, if you put a wind speed recorder on that airplane, it will show a constant 20 mph.

And, crashes can happen, when the pilot tries to fly the model at the same apparent GROUND speed. So if he tries to fly that model downwind at what looks to be 20 mph, its actual wind speed is zero, and the model hits the ground.

Think of a helium balloon released into a 20 MPH wind. The balloons Ground speed will be 20 MPH, (downwind). But since it has no motor or power system, its AIRSPEED is zero (Ignoring that it is rising upwards)

[Figure.N9ne]

Originally Posted by wolfewinde

Let me try to better understand this

Let's say the plane is flying at 20 MPH straight across a 10 mph wind. Wouldn't airspeed and ground speed both be the same at 20 mph at that point?

Then let's say you make sharp turn into the wind. Wouldn't you still be going 20 mph with an additional 10 mph of wind now flowing over the wings? So wouldn't your effective Airspeed now be 30 mph. Wouldn't you have to slow the plane down to 10 MPH ground speed to maintain a 20 MPH airspeed? = 10 ground speed + 10 windspeed

I could be wrong here - it has been a while LOL

Wolfe

you forgot to factor in the drag, once you turn into the wind, it'll decrease your ground speed unless you apply more power. This about what happens when you fly a model at full throttle into a 20 mph head wind, then turn around at full throttle and fly with a tail wind. The ground speed is much higher with the tail wind, even though you're at the same power level.

[kyleservicetech]

Originally Posted by Yaniel

you forgot to factor in the drag, once you turn into the wind, it'll decrease your ground speed unless you apply more power. This about what happens when you fly a model at full throttle into a 20 mph head wind, then turn around at full throttle and fly with a tail wind. The ground speed is much higher with the tail wind, even though you're at the same power level.

Yup
Which is why you always try to take off and land INTO the wind. If you've got a 15 MPH wind, taking off into the wind versus taking off downwind is a 30 MPH difference in the models air speed when lifting off. Even though once in the air, the models AIR speed is pretty much the same, with the same power setting, and flying straight and level.

For the folks that flew control line models, you had to be aware of BOTH the airspeed and ground speed of your model as it flew around the circle. A severely underpowered control line model could be flying to fast into the wind, and stall out on the other side of the circle, and loose line tension, and crash.

[wolfewinde]

Ahhh - OK ty all - I think I have it now.

Wolfe

[mred]

The speed of a plane is determined by the power setting you use. If you set the airspeed to 20 mph and don't change the throttle stick again, then the plane will fly at 20mph no matter what direction it is going and the speed of the wind has nothing to do with this. It is just the power setting that you are using that determines how fast you fly. You can turn and bank all you want and the speed of the plane overall with that power setting will stay the same. Now the ground speed will be changing, but the airspeed in not dependent on how fast it is moving over the ground, just how fast the air is moving over the wing. This is assuming a constant wind speed and no turbulence that will affect the plane.

Now add the turbulence and that is a whole new game. The plane will only react so fast to any change in wind velocity, so if you get hit with a gust of wind that is a direct headwind that hits 20mph, then the plane will try and slow down to 20mph from the head wind that just hit it. That 20mph airspeed and 20mph gust add together, so you have 40mph wind going over the wing and since the throttle is set for a 20mph airspeed, it will slow down. Lets say that the gust is long enough for the plane to slow down all the way to 20mph again and then the gust goes away and you no longer have that wind speed going over the wing. Now all of a sudden the wing has no air movement going over it and it drops the nose and tries to get back to that 20mph flying speed again. If you are high enough then you simply recover and go flying again. If you happen to be on approach and that happens close to the ground, then your plane will nose into the ground trying to get it's airspeed back. That is the major hazard flying in turbulent air and has caused may plane crashes for that reason. The only way to avoid that is to carry extra throttle and when you hit a gust give it more throttle so it will stay in the air when the gust goes away.

Really, the best thing to do is just don't fly on days that have a lot of wind. That turbulence can kill your plane real fast if you don't know how to fly in it. Most people will quit flying at about 20mph winds and some sooner. I have flown in 30 mph just for kicks once and it is not fun at all. It is to much like work and I want to enjoy flying, not work at it. On windy days, try going early in the morning or late in the day when the wind normally drops down again. You will enjoy flying much more...............

Ed

[Tom Sawyer]

Totally agree with mred on the best time to fly; the lowest wind speeds are often very early in the morning and last thing in the evening although that may not neccesarily coincide with when you have the most desire to go flying!

I normally look for a forecast of 0-5mph but even then will get up at dawn and aim to be flying as soon as I can comfortably see the model without fear of orientation issues. Sometimes you only get 30mins of still air and sometimes never at all but more often or not (assuming a good forecast!)there is a perfect window that you would easily miss if you left it to late morning.

Where I live the wind seems to suddenly just 'switch on' and Ive often got all the way to the field in still air only for it to spring up when I arrive.

Likewise there is often a great 30min slot last thing in the evening but watch out for orientation issues as the light levels can drop before you notice so land before this happens!

Still air will also make your planes fly more scale if you enjoy flying those sorts of aircraft.

Ive been flying on and off for a while and even now I only fly in winds over about 8mph if I really have to because over 5mph I just dont enjoy it.

Another advantage is that In the summer I get up very early, go flying and then go back to bed before the wife even notices!

[Scott Page]

http://www.mycoolrc.com/gyro/index.html

It may have been said already in this thread, I don't recall - but equiping your plane with a $15 or $20 rate gyro for the aileron channel is a very effective method of dampening the unscheduled rolling that comes from turbulence. The link above is a treasure trove of info. Also search in YouTube for "aileron gyro" and there are some good videos of folks flying very light foamies in pretty high wind. Of course like everything in the hobby from ARFs to connectors, gyros have their detractors. I just figure it's a question of whether you want to fly when it would be otherwise unflyable or not.

[mred]

I agree that gyros can help with some things on a windy day, but that still does not help with landings in gusty wind. Small lite park fliers are great in 5mph or less and they are fun to fly, but much beyond that even with gyros they get to be a hand full. If you like flying and want to fly more, then you need a bigger and heavier model to handle the wind better. A park flier that weighs 25oz is going to get blown around much more then a 6 pound model and the heavier model will keep it's momentum much better in wind then a lite one will. It all depends on what kind of model you have and how good you are at handling the wind, but even the big models will get to be a hand full in higher winds. The 30mph winds I flew in were with a 12lb model and it was quite a hand full even then. All I can say is, pick the wind speed you are comfortable with and stick to that. Anything more and it takes the fun out of it.

Ed

[HobbyJumper]

Great advice imho

Originally Posted by mred

Small lite park fliers are great in 5mph or less and they are fun to fly, but much beyond that ...they get to be a hand full. If you like flying and want to fly more, then you need a bigger and heavier model to handle the wind better...pick the wind speed you are comfortable with and stick to that. Anything more and it takes the fun out of it.

Ed