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-   -   Thoughts on reinforcement plates!?? Discussion (https://vansairforce.net/community/showthread.php?t=199395)

JeremyL 09-21-2021 12:19 PM

Thoughts on reinforcement plates!?? Discussion
 
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So as I am assembling my elevators, I noticed the area behind where the elevator control horn doesn’t have a reinforcement plate. Thoughts/discussion on making some reinforcement plates and putting them here to help the load? Now I’m no engineer but it seems like that may be a decent spot for extra reinforcement to prevent future issues. All comments, thoughts welcome…

Sam Buchanan 09-21-2021 12:21 PM

I'm not aware of any "issues" that have shown the need for reinforcement.

John Tierney 09-21-2021 12:52 PM

I wouldn't add extra weight to the tail. The -7 elevator cracks noted in SB 14-02-05 were found at the rod end hinge points, not the horns.

JeremyL 09-21-2021 01:05 PM

I haven’t seen any issues yet either. Also do you think the few extra grams/ounces would be a huge difference to the tail?

rocketman1988 09-21-2021 01:10 PM

Extra weight
 
Can’t say for sure in this case but yes, a few extra ounces/grams can have an effect. On a control surface, I would follow the plans…

David Paule 09-21-2021 01:13 PM

I weigh most things that I add to the plane in grams and try to minimize them. If you want a light airplane, we've got to pay attention to things like that.

Also, it might be helpful to talk with a real structural engineer and ask that person to show you some examples of airplane load paths. In this case, there is an ample load path built in.

Dave

alpinelakespilot2000 09-21-2021 01:39 PM

Be careful. A solution in search of a (non-existent) problem often leads to (real) problem.

JeremyL 09-21-2021 02:10 PM

Interesting points of view, and yes the load is dispersed via the long parts of the horn. Just spitballing for conversation, I’m almost certainly going to follow the plans in this area. I should have been an engineer haha

BillSchlatterer 09-21-2021 07:35 PM

There is a plate
 
The skin in a monocoupe design carries a lot of the various loads. It is effectively the plate you are considering. It would only need reinforcing if their were buckling or stress points specific to that area.

Van is an aeronautical engineer with a stellar record and there are 10,000+ flying. :) The thing that slows many many builders down is trying to improve a design and add "improvements" :rolleyes: where there is no need.

If you aren't capable (and I'm not for sure :o ) of doing a true structural load test or have builder/designer knowledge that exceeds Vans group, you should probably work hard on building the airplane specifically to the plans. That is the quickest and safest way to get a kit in flyable form.

Just my .02 after building a couple and watching several get the "improvement" process where none were needed.

Awesome airplanes...:)

Z-EDD 09-21-2021 10:32 PM

Quote:

Originally Posted by BillSchlatterer (Post 1557141)
The skin in a monocoupe design carries a lot of the various loads. It is effectively the plate you are considering. It would only need reinforcing if their were buckling or stress points specific to that area.

Van is an aeronautical engineer with a stellar record and there are 10,000+ flying. :) The thing that slows many many builders down is trying to improve a design and add "improvements" :rolleyes: where there is no need.

If you aren't capable (and I'm not for sure :o ) of doing a true structural load test or have builder/designer knowledge that exceeds Vans group, you should probably work hard on building the airplane specifically to the plans. That is the quickest and safest way to get a kit in flyable form.

Just my .02 after building a couple and watching several get the "improvement" process where none were needed.

Awesome airplanes...:)

I think bill meant “monocoque”, and this is the key. The structure as pictured may seem flimsy, but add the skin and it becomes a rigid box, plenty strong.


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