art43

Can someone tell me how to convert degrees to inches ? My controls are are in degrees and I need to get to inches. art43

Steve Guinn

Now that would take a whole lot of equations. Think I would go to plan B.
:bananahea

art43

That was Plan B. No Plan C,

tomd-RCU

In order to change degrees to inches one must multiply the width of the rotating surface by the angle in radians. So here is the equation that you should use. This equation takes care of the change to radians.

(# inches) = (width)*(Angle in degrees)*3.1416/180


Hope this will help

Lightfoot

My Feedback: (1)

That will give you the rotational (circular) distance. I think what he is looking for is the linear deflection of the control surface. The formula for that would be:

linear deflection = (width of control surface) * (sine of angle of deflection)

The calculator on any Windows operating system can handle the calculations.

Roby

1 degree = .017 inches (17 thousandths of an inch)

If the surface is 1 inch wide and is deflected 10 degrees
it will move 10 x .017= .170 inches , roughly 3/16 of an inch.

If the surface is only 1/2 inch wide divide .017 in half.

If the surface is 2 inches wide multiply .017 x 2.

The .017 is a rule of thumb thing and may help to keep the calculating "simple"

Regards,
Roby

tomd-RCU

I would like to respond to Lightfoot and say that multiplying by the sine of the angle is good, but is an approximation. The relation is valid up to about 10 degrees and after that the error increases.

P-51B

My Feedback: (5)

Anyone thought of just using a ruler to measure the deflection?

MinnFlyer

My Feedback: (4)

thank you P-51!

Jeeze you guys get technical! How about an eyeball instead of a ruler. Set you controls up so they have a nice deflection. THEN GO AND FLY THE PLANE! The MFGR is just giving you a starting point anyway. It's not like if you're off a little you're going to crash the plane. If you're worried you're going to crash, you should have a more experienced flyer test fly it first anyway. Then decide how you want it. This ain't rocket science fellers. What may be the right control throws for me may be not enough for you, and vice versa

Roby

There is a ruler that will do this conversion ?

P-51B

My Feedback: (5)

Rulers are available that measure in inches or in metric units!!!!


Using either one will give you the vertical deflection as specified by manufacturers. You see, they normally say somthing like, the deflection should be 1.5 inches at the inboard trailing edge, etc. This measurement is a total vertical measurement, not along the arc of travel.

Now if he has been given degrees of deflection at a given distance, then a PROTRACTOR is the appropriate device to use. Easy.

MinnFlyer

My Feedback: (4)

Ok, try this...

Look at the picture. Don't measure it, just look at it. Now set up your elevator with the same deflection BY EYE. Set the rudder with a little more, and the aileron with a little less, then fly the plane. Get up good and high before trying anything like a roll or a loop. Land, and make whatever changes you want.

If you don't think you can do this, then you are not ready to "maiden flight" a plane and should have someone else fly it for you regardless of how it is set up.

Roby

I suppose that there are many ways to set-up an
airplane all ranging from simple to complex.

But keep in mind that:

The question WAS :

How to do a conversion from degrees to inches.

We should focus on and answer that question first , then ,and only then , offer an effective alternative process so as to end with
the same result.

Regards
Roby

Rodney

arctan of degrees times width = inches of deflection. Do you not take algebra in school anymore?

Rodney

I tried to edit the above, looks like I need to go back to school. I should have said that the deflection =tan(angle in degrees)times the width, not arctan.

art43

My H9 Skhoi has the controls in degrees, and I was hoping there was a simple way to convert to inches. They had algebra when I went to school,but I took girls instead. Now to old for girls, need algebra. art43
P.S. thanks for all the info.

Steve Guinn

Told you!

OldRookie

My Feedback: (13)

Use this equation.

width of the control surface=A
angle of surface deflection=B
A X TanB=amount of control surface movement

2" wide elevator @ 20 degrees of deflection

2 X Tan 20 degrees

2 X .36397 = .727

Greg

Lightfoot

My Feedback: (1)

Take a look at the attached diagram. From our high school trigonometry, the sine of an angle is opposite, (O - deflection) over/divided by hypotenuse (H - width) or:

sine = O/H

To determine the opposite/deflection, we solve using high school algebra by muliplying both sides by H:

O = sine * H

or:

deflection = sine * width

Roby

Art43 , Arn't you glad you asked this question ?

I hope that at least some of the responds that you got
helped out . Don't feel badly that your having trouble
with the math.......there are a lot of people that are in the
same boat.

For others that can do these calculations , we sometimes
forget that if a person knew what Sine,Cosine and Tangent
was.........and how and where to look for them, the question
would not have been asked in the first place.

Art43 , send me a private message with your needs
and I'll run the numbers for you.

Best regards,
Roby

Lightfoot

My Feedback: (1)

If you are running a Windows operating system, open the calculator.
[list=1][*]Click the "View" button[*]Click "Scientific"[*]Click the number that corresponds to the control surface width (1.5 for 1 1/2")[*]Click the asterisk (*) key to multiply[*]Click the keys to enter the angle (15 for 15 degrees)[*]Click the "sin" key[*]Click the "=" key[*]The number displayed will be the deflection in inches[/list=1]

It is just that simple.

MinnFlyer

My Feedback: (4)

Is that linear inches, or arc inches?

(Just stirrin' up the pot LOL)

OldRookie

My Feedback: (13)

I didn't see Lightfoots post. This is more of the same.

You don't need to know what Sin Tan mean. Just press the right button on the scientific calculator that comes with your OS.
Open your Windows calculator. Select view from the menu bar, and select scientific. Now enter the angle, and now press the button for what you want, Sin Tan, etc. That is it.
If you are not sure where the calculator is go to Start button, then program, then accessories, and it should be there.

Hope this helps,
Greg

art43

Thanks everyone for all the information, even from the guy who chewed me out for not taking algebra in school, and I will try that scientific calculator in windows. If I can't get what I want I will send Roby an email. Thanks Roby for the offer to run the numbers for me, I may be contacting you soon. Art43