Message #667

Date: Oct 16 2000 01:24:00 EDT
From: "" <>
Subject: Re: Fig. 1-7 Detail C

At 08:34 PM 10/15/2000, you wrote:
>So you're saying, Steve, that 25 1/2 and 52 1/2 for
>station  3 and 5 respectfully at the top longeron are
>not correct?  I certainly hope this is not the case
>since my fuse was built to those dimensions.  Will my
>angle of incidence be off after using the "corrected
>dimensions?  Great idea though to use a full size rib
>during fuse construction.

Hi Matt:

the corrected dimensions are fine. At least I hope they are.

But, if you didn't use a template of some sort to check for the wing's 
angle of incidence BEFORE putting the fuselage together, it may be a good 
idea to measure now. See page 8-7 paragraph 8 for more details on how to do 
this. I feel there should be a mention somewhere in section 1 so builders 
can pre-set the angle of incidence while building the fuse sides.

Had I finished mine the way that I thought it was supposed to go together, 
I would have ended up with a very expensive go-kart as the wing wouldn't 
have fit the fuselage. I was off by a 1/4" but the biggest problem was that 
the angle of incidence was way, way off!

By following Steve's suggestion, I was able to determine the right angle 
for the short uprights at stations 3 and 5. And, in spite of this approach, 
they still came in at the low end of the scale, but within acceptable 

My original concern was that I wanted to insure the wing spar fittings 
would slide into the fuselage with no binding and I felt that I needed to 
set the precise angle for the short uprights to achieve this. Well, come to 
find out, the best approach is to use some sort of template and determine 
the position using this method. Once you've determined this, remember to 
measure from the centerline of each upright. The distance should be 27 inches.

Apparently there are a lot of "little" details missing from the builders 
book. Thank God for this list!
Having said this, there also seems to be quite a bit of "tolerance" built 
into Fly Baby as the note at the end of paragraph 8 indicates:

"The wing angle of incidence can be adjusted through a small range by 
sliding one set of spar fittings up or down the appropriate fuselage 
station until the fittings begin to bind."

Then it goes on to mention some fix by way of a rasp (Egad!). I guess this 
is OK, but to me sounds like determining the torque of a bolt by tightening 
until it begins to strip, then backing it 1/4 turn. Call me picky.

And, since we're on the subject, I think it may be a good idea to wait 
until the wings are ready to be mated to the fuselage before drilling the 
spar attach holes.

Also, if any of you is incorporating the spar reinforcing plates, they have 
to be flush with the plywood. I noticed this detail while studying the Fly 
Baby on display at the Sun 'n Fun Museum.


Luis Hernandez Jr.
Payne Corporation  |  |  |  |  |

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