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-   -   Convert Millimeters to Degrees (https://www.rcuniverse.com/forum/rc-pattern-flying-101/10705231-convert-millimeters-degrees.html)

jarvis johnson 09-06-2011 11:15 PM

Convert Millimeters to Degrees
 
Need some help converting millimeter throw to degrees. What do you guy's do

example Ailiron state 20mm up/ 20mm down
Elevator state 8 mm up / 12mm dowm
Rudder state 30 L / 30mm R

How do you convert the throws, do you use a rule or is there a throw meter that reads in millimeters


Thanks For the help

DagTheElder 09-06-2011 11:26 PM

RE: Convert Millimeters to Degrees
 
Hi,

Just use a caliper on the leading edges.

Regards

Sorry, i meant trailing edges [&o]

Rendegade 09-06-2011 11:39 PM

RE: Convert Millimeters to Degrees
 
deflections in millimetres are control surface dependant. If you want to convert it to degrees you need to know the length of the surface and then use your trig to figure out the degrees.

I just use a deflection meter with millimetres, of if you have one in inches, divide the mm by 25.4 to get inches.

Magne 09-07-2011 12:31 AM

RE: Convert Millimeters to Degrees
 
You need to divide the throw (eg. 20mm) by the chord of the aileron (eg. 80mm) and take the inv. sin to that number.
(e,g, 20/80=0.25 sin-1 0.25=14 deg.)

Magne

Stuart Chale 09-07-2011 02:09 AM

RE: Convert Millimeters to Degrees
 
Try this on the NSRCA website.
http://nsrca.us/index.php?option=com...ding&Itemid=95

It is something I made by modifying the one from aero-perfect.
It should do what you want.

Stuart C.

Gibson-Denmark 09-07-2011 02:31 AM

RE: Convert Millimeters to Degrees
 
1 Attachment(s)
Hi Jarvis,

I have done a few examples, the way I learned it. Its pretty much the same as Magne showed you.

Best regards

Michael Gibson

Nathan King 09-07-2011 04:52 AM

RE: Convert Millimeters to Degrees
 


Grab a calculator. The control surface deflection in degrees would be Sin-1(deflection/length). The Sin-1 is inverse Sin.</p>

Jetdesign 09-07-2011 07:22 AM

RE: Convert Millimeters to Degrees
 
Eyeball it, then use your gage to make sure throws are consistent (ailerons same, elevator same, etc). Numbers in the manual are a reference, you will most likely end up changing the throws to your liking. Common start points are 10deg ail/ele and 45 (I think) for rudder. I used to try the conversions and use numbers, but after making changes I got tired of keeping track and doing math.

The throws on my Wind are so far below the recommendations in the manual, maybe 7 degrees now. If you have dual/triple rates, you can do something like 5deg, 10deg, and 15deg. Takeoff at 10 and switch if needed.

tail strike 09-07-2011 08:46 AM

RE: Convert Millimeters to Degrees
 


ORIGINAL: Magne

You need to divide the throw (eg. 20mm) by the chord of the aileron (eg. 80mm) and take the inv. sin to that number.
(e,g, 20/80=0.25 sin-1 0.25=14 deg.)

Magne
Huh

Strat2003 09-07-2011 08:50 AM

RE: Convert Millimeters to Degrees
 
I do that sort of thing graphically. I draw the control surfaces and suggested throws full size and measure the result with a protractor.

But then, I'm mathematically dyslexic, lol.

Scott

Mastertech 09-07-2011 09:23 AM

RE: Convert Millimeters to Degrees
 
You want that in Metric Degrees or English Degrees?


:D

Tim

Strat2003 09-07-2011 10:42 AM

RE: Convert Millimeters to Degrees
 
In Metric degrees there are 100 degrees in a circle, right? And Pi is 3.0?
:D

Red B. 09-07-2011 02:42 PM

RE: Convert Millimeters to Degrees
 
Google can do the calculations for you. Enter:

180/pi*arcsin(deflection/chord)

in the search field using the same units for the deflection and control surface chord.

Example:

180/pi*arcsin(20/50) = 23,6 degrees.

CGRetired 09-07-2011 03:43 PM

RE: Convert Millimeters to Degrees
 
Man, this is making a mountain out of a mole hill. This is not rocket science, folks.

The deflection in mm is denoted for that specific model and is measured at the trailing edge as noted above by Rendegade.

Joe also makes a good point because this is just a starting point for any control surface and will, most likely, be changed by the owner to suite his/her needs.

If it says Ailiron 20mm up/ 20mm down, well, measure that at the trailing edge. Who cares what the degrees of throw is at that point. Set it up and fly it. If you don't like it, change it. Then measure it and figure it out if that floats your boat. Arcsin(deflection/chord)? If you have had Trig, then that's alright. If not, then what's an arcsin?

CGr.

jarvis johnson 09-07-2011 05:27 PM

RE: Convert Millimeters to Degrees
 
Thank You!!!!
I will just use degrees, an go from there, thanks to everyone that replyed.

MTK 09-07-2011 07:01 PM

RE: Convert Millimeters to Degrees
 


ORIGINAL: CGRetired

Man, this is making a mountain out of a mole hill. This is not rocket science, folks.

The deflection in mm is denoted for that specific model and is measured at the trailing edge as noted above by Rendegade.

Joe also makes a good point because this is just a starting point for any control surface and will, most likely, be changed by the owner to suite his/her needs.

If it says Ailiron 20mm up/ 20mm down, well, measure that at the trailing edge. Who cares what the degrees of throw is at that point. Set it up and fly it. If you don't like it, change it. Then measure it and figure it out if that floats your boat. Arcsin(deflection/chord)? If you have had Trig, then that's alright. If not, then what's an arcsin?

CGr.
Hey, isn't ArcSin the head of all Sins??

He, he, devil made me do it; couldn't resist

nonstoprc 09-07-2011 07:24 PM

RE: Convert Millimeters to Degrees
 
+1 for the measurement of travel distance in mm. More accurate.

hook57 09-08-2011 04:35 AM

RE: Convert Millimeters to Degrees
 


.....</p>

Eagleburger 09-08-2011 05:12 AM

RE: Convert Millimeters to Degrees
 
TLAR

DagTheElder 09-08-2011 05:28 AM

RE: Convert Millimeters to Degrees
 

ORIGINAL: MTK


He, he, devil made me do it; couldn't resist
[/quote]

Any other complicated way to do this?[:@]

Best d....ish regards

Warbirdguy 09-08-2011 06:50 AM

RE: Convert Millimeters to Degrees
 
Bah!!!! I just set everything to maximun throws, then set dual rates to half that, then fly it and back off settings till it flies like I want it too :D Since yours is in mm's, I assume its a ....not built in USA....kit or arf[:-] Those guys are too anal about stuff like that. Do it the good old American way, by the seat of your paints :)

MikeRuth 09-08-2011 06:56 AM

RE: Convert Millimeters to Degrees
 
Use one of these....

http://www3.towerhobbies.com/cgi-bin...?&I=LXK260&P=0


Columbus Ron 09-08-2011 11:12 AM

RE: Convert Millimeters to Degrees
 
Don't worry about the what the manufacturer says as far as surface deflection in mm or inches. Set ailerons, elevator and rudder to full defection (before the surface begins to bind) when at high rates. Then set low rates at about 15 deg for ailerons and 15 deg for elevator. Use 50% or more expo when on high rates. Use 25% or lower when on low rates. I make the rudder deflection for high and low rate to be the same. I use about 50% expo on rudder. Fly the plane then adjust the rates and expo to soot your personal preference.

Warbirdguy 09-08-2011 11:22 AM

RE: Convert Millimeters to Degrees
 


ORIGINAL: Columbus Ron

Don't worry about the what the manufacturer says as far as surface deflection in mm or inches. Set ailerons, elevator and rudder to full defection (before the surface begins to bind) when at high rates. Then set low rates at about 15 deg for ailerons and 15 deg for elevator. Use 50% or more expo when on high rates. Use 25% or lower when on low rates. I make the rudder deflection for high and low rate to be the same. I use about 50% expo on rudder. Fly the plane then adjust the rates and expo to soot your personal preference.

LOL more or less what I just said :eek:

WBG

Freddy 09-08-2011 01:49 PM

RE: Convert Millimeters to Degrees
 
I agree with CGRetired! Talk about making rocket science that is not necessary. Just measure the throw at the outboard tip (or inboard tip if specified) of the trailing edge of each control surface directly with a ruler in mm.

Of course you can use trigonometry to get to degrees using the surface chord length but why complicate things?


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