Plane behaves differently between flying sessions

[quorneng]

There is a huge difference between the effects of wind and turbulence on a model plane, particularly a very light one.
Wind if fairly obvious. You can feel it and it is constant although it does tend to get stronger the higher up you go.
Turbulence is caused by things on the ground and the completely disrupts the airflow. This means that as far as a model plane is concerned the air it is travelling through can in the space of a couple plane lengths change its direction both horizontally and vertically. This is likely to have a very dramatic effect. To make matters even worse a gentle wind, the sort that you might feel safe for a slow flyer creates relatively even more severe direction changes.
Low level ground turbulence can persist for many times the height of an object. Down wind of a full height tree can persist for the length of a football pitch.
So if your plane has a flying speed of say 15 mph and you fly in a gentle 5 mph wind it would be quite manageable but any turbulence effects and it is likely to be thrown about almost to the limit of its control.
Not quite the same thing but this picture does show the lasting effect of wind turbines on smooth misty conditions.

Of course in normal clear air conditions you will none of it but it is still there.

 

[Aviator936]

I'm flying (novice) a Simple Cub and get the plane trimmed and flying perfectly. Two days later I'll go for another session (same location) and it flies very erratically, diving to the left, difficult to control. I don't get it? Thanks.

dont worry about it. it always happens just have someone who can trim it up for you and keep it safe in between flying sessions. when it gets bumped around in the car the trim is wrecked and things like that. id also say that you are a bit nervous when flying for the second time?. just throttle back and the sensitivity wont be quite as bad and then you will be able to see if its a trim problem or something worse.

 

[Aviator936]

i usually speed up if it is behaving strangely. if it is wind, performance improves. if not, i crash

id say that speeding up in wind is ok but not if its flying erratically. the faster you go the more wind is going over the control surfaces. relax and throttle back id say

 

[Robert S]

Does your control board have gyro stabilization? If it does, make sure your board isn't loose and moving around. If it is, then that is going to cause the plane to fly erratically as the board trys to keep the plane flying in what it thinks is level while its bouncing around.

 

[boogieloo]

Do they give instructions for adjustment on your control box? Or is this one of the issues of stabilization. Like the specialized receivers they have.

I'm not going to be sarcastic, but nothing are those issues. Just fly the thing in the trees and see if you can fix it, is where i am at. Then make a better one.

 

[bisco]

i thought you had not flown yet

 

[TheFlyingBrit]

I have a lot of problems with wind, its just part and parcel of living in the UK.
Our club has some open areas and other areas sheltered by trees, so you get both calm and turbulence in the space of a few 100 meters.
I don't tend to play about with trim much anymore, because if I did it would probably change virtually every time I fly.
What I have learned to do is maiden my planes on days with very little wind, that way I can trim the plane to flying straight and level with no wind effect.
As long as nothing changes on the model after that initial flight, its set-up and settings should remain constant. That way if the model starts flying erratic I can usually determine its wind effect and compensate with my sticks.
Only if I can be sure its not wind and the plane wont fly straight and level, then I would land it and give it a once over to check nothing has changed. If I find no problems with the model and the second flight has the same issues, then I would consider a trim adjustment.
After a while you get to recognise the effects of wind and turbulence and your able to compensate, its part of the learning process .

 

[Bifi.baarlo]

Do they give instructions for adjustment on your control box? Or is this one of the issues of stabilization. Like the specialized receivers they have.

I'm not going to be sarcastic, but nothing are those issues. Just fly the thing in the trees and see if you can fix it, is where i am at. Then make a better one.

Good idea, when a plane doesn't fly very well, land it in the trees.

 

[bisco]

that seems to be my sop

 

[TheFlyingBrit]

I always use flight stabilisation on my models, its called thumbs

 

[boogieloo]

I'm flying (novice) a Simple Cub and get the plane trimmed and flying perfectly. Two days later I'll go for another session (same location) and it flies very erratically, diving to the left, difficult to control. I don't get it? Thanks.

Is this the spitfire? Or the trainer? I forgot. Perhaps it is the adjustments. Does this thing fly really fast? I need more description. Can it go around building and trees?

How long have you had this model airplane?

 

[Bifi.baarlo]

Is this the spitfire? Or the trainer? I forgot. Perhaps it is the adjustments. Does this thing fly really fast? I need more description. Can it go around building and trees?

How long have you had this model airplane?

A simple cub is not a spitfire and not very fast around buildings and trees.