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Setting up a Biplane's Wing Incidence (Read 4582 times)
Reply #2 - Feb 10th, 2013 at 4:25pm

Sky9pilot   Offline
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Kelso, WA 98626 USA

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You are correct.  I usually try to find a datum line for construction and make measurements off that line. Often the plans will have a datum line already on the plan.  This will be a line that runs through the nose of the fuselage through the tail end of the fuselage. The wing saddle for the lower wing will usually show the incidence suggested on the plan.  You can measure from the datum line to show the angle of incidence along the bottom of the lower wing from trailing edge to leading edge.  Most freeflight models use a flat bottom wing rather than semi or symmetrical wing layout.

When setting up the wings for a bipe, I make a jig that will align the bottom wing panels at the decided incidence, then jig up the top wing at zero incidence in relationship to the incidence of the lower wing.  The horizontal stab is usually in a slot that allows shimming the leading edge or trailing edge for incidence adjustment. 

There are as many ways as there are modellers to set things up for incidence on bipes and monoplanes.  Some construct a permanent jig that can be used with multiple models and some use the foam boards and make a jig for each aircraft.  To each his own.  Find what works for you and don't be afraid to experiment.  This is a starting point for me. 

You might want to check out the trimming threads on this site for more info...If you need further clarification please feel free to ask. 

Tom
 

If God is your Co-pilot...switch seats...
Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
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Reply #1 - Feb 10th, 2013 at 10:18am

Konrad1   Offline

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San Francisco Ca, USA

Posts: 19
 
Tom, Is there an accepted standard as to what is the datum one use for measuring incidence?

When I read,  "with the horizontal stab adjustible for initial trimming starting at approximately -2 degrees incidence" I assume you are measuring from the wing defined as zero, the upper forward wing.

All the best,
Konrad
 
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Mar 10th, 2012 at 12:51am

Sky9pilot   Offline
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Kelso, WA 98626 USA

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Hi all...dealing with Biplanes/Sesiquiplanes and what incidence to set the upper and lower...forward and rear wing...

Rather than re-invent the wheel, so to speak, I will link you to a rather detailed discussion on HPA (Hip Pocket Aeronautics) site...The consensus is...."There is no consensus!"... Click here: Biplane wing setup

In my personal experience with two Bipes (Born Loser and Curtiss Helldiver F8c)  There was 0 degree on the upper/forward wing and +2 to +3 degrees on the lower/rear wing... with the horizontal stab adjustible for initial trimming starting at approximately -2 degrees incidence...

Tom
« Last Edit: Feb 10th, 2013 at 4:42pm by Sky9pilot »  

If God is your Co-pilot...switch seats...
Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
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