CB1 Spar in Comparison to Kelly D

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jcadwell
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Joined: Sun Oct 16, 2011 1:12 pm
Location: Washington State

CB1 Spar in Comparison to Kelly D

Post by jcadwell »

I'm going to CA to look at a Kelly D tomorrow, and was hoping for some info regarding the spar upgrade of which I have heard rumors.

Is the CB1 Spar the same as a Kelly D spar? Is the analysis performed on the CB1 relevant?

Does anyone have drawings or info on what the upgrade should look like?

Thanks, John Cadwell
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dougm
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Joined: Wed Mar 17, 2010 2:39 pm
Location: Douglas, MA
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Re: CB1 Spar in Comparison to Kelly D

Post by dougm »

Hi John,
Well, I do not have any experience with a Kelly-D and I'm no aeronautical engineer, but I would not think the CB-1 analysis could be applied to the Kelly-D. They are different airplanes that happen to share a common support organization. One key difference between the two is that the Hatz has a three piece top wing - left & right panels and a center section; the Kelly-D is a two piece wing - left & right panels attached at the cabanes (which are also different from the Hatz).

Perhaps someone here with more experience can shed some additional light.
Doug.
Doug
Building Hatz Classic s/n 093 & Rotec R3600
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wassbiplane
Posts: 29
Joined: Wed Mar 24, 2010 1:35 pm

Re: CB1 Spar in Comparison to Kelly D

Post by wassbiplane »

There has been an analysis done on the kelly-D---but a biplane cellule has to be analyzed in its entirety-- Top& bottom wings,
all the flying wires, and especially the N struts , as a true analysis is dependent on the "sharing" of the loads between all the members..
If you draw up a space frame of a biplane cell, apply some loads produced by the wings , and then try to solve the force
diagrams by simple triangulation --you come to a couple of points where the force is distributed by TWO struts---The
question is --How much in each strut. One of the first methods was by the theory of "least Work" which is what I used.

I have done an analysis on my K-D , but--I have mostly 7/16" flying wires (bought VERY cheap) and some old Piper wing struts
used for the N struts (same $ reason), and Doug Fir spars.

If you search the Hatz/K-D website I'm sure you could find the analysis done by Jurg Mueller (sp-??)

Jerry Wass
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