Incidence meters

[Rcmaster199 at aol.com]

A couple of thoughts on this thread:

First, for a model that has progressed enough to have all the pieces built-- 
the easiest way to get the various angles needed is with a transit. There are 
alot of benefits, the most important of which is this: the model doesn't need 
any fancy surface tables or any lazer beams to get it level, because it really 
does not need to be level. All measurements are made relative to the 
transit's plane of rotation, so the model's attitude only needs to be adjusted to be 
parallel to this plane. And if you want to be absolutely dead certain that stab 
and wing are parallel, well that's straight forward also

Transits can be expensive devices but eBay may have something for cheap. 
Learning to use one is not that tough really, and shouldn't pose a problem for 
most any pattern flier.

The easiest way I have found to determine the zero thrust line on a glass 
fuse, is with sewing thread. The center at the nose is fairly easy to get exact, 
so I tie a length of thread from the nose center to the tail post, at the 
appropriate height on the post so the fuse sets properly. Scribe lines are then 
transcribed to the outside of the fuse.

My penny's worth FWIW

Matt Kebabjian


> Subj:Re: Incidence meters 
> Date:5/21/2003 5:41:30 PM Eastern Daylight Time
> From:<A HREF="mailto:ojfrets at earthlink.net">ojfrets at earthlink.net</A>
> Reply-to:<A HREF="mailto:discussion at nsrca.org">discussion at nsrca.org</A>
> To:<A HREF="mailto:discussion at nsrca.org">discussion at nsrca.org</A>
> Sent from the Internet 
> 
> 
> 
> I guess I'll keep doing the way I always do it. I was looking for an easier
> way to do the incidence. I do a bit scratch building, during the building
> process, lines reference lines are drawn on the wood surfaces. I generally
> level the plane to the work surface using the stab or the reference
> markings as a reference point. Then mark a line that is parallel to the
> work surface and measure from  that line and/or the work surface.
> I use a string and line level for leveling for the setup. Works pretty well
> but is time consuming. Also pretty accurate.
> Thanks to all who replied. This list is pretty good!!!!!!!!!!!!!!
> 
> Orlando
> 
> 
> > [Original Message]
> > From: Kenneth Blackwell <kblackw at snowhill.com>
> > To: <discussion at nsrca.org>
> > Date: 5/21/2003 9:28:41 AM
> > Subject: Re: Incidence meters
> >
> > Paul,
> >
> > The line that you mentioned is the "zero thrust line" and it is determined
> > by the designer when the airplane is laid out. If you are starting with a
> > kit, the kit manufacturer should provide information that will allow you
> to
> > set up the incidences corectly. Sometimes this is accomplished by
> specifying
> > how to set the fuselage up on a flat surface, by blocking up the tail a
> > specified amount. Then, you can measure up from that flat surface to the
> LE
> > and TE....and calculate the incidence angle with trig....etc. etc. Another
> > way that manufacturers specify the incidences is by scribe lines or mold
> > lines on the sides of the fuselage.
> >
> > In the end, the most accurate way to determine incidences is by measuring
> > LE/TE from a good flat surface....as Jerry Budd has already stated
> earlier.
> > We need to be able to set incidences to an accuracy of about 0.1 deg and
> > this just isn't possible with any of the devices mentioned...so far.
> >
> > Cheers,
> >
> > Ken Blackwell
> >
> > ----- Original Message -----
> > From: "Paul Lawrence" <pwl45 at yahoo.com>
> > To: <discussion at nsrca.org>
> > Sent: Wednesday, May 21, 2003 7:56 AM
> > Subject: Re: Incidence meters
> >
> >
> > > Speaking of incidence, what is the best way to find the thrust line for
> > > measuring the incidence?

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