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Are US experimental aircraft safe?

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Billie

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I have one Skybolt and on the basis that it is tricky to have too much of a good thing I wanted another. I came across a suitable project for me to complete in the US but I as live in the UK homebuilt aircraft are regulated by the LAA.

The project has balanced ailerons and clipped wings and so I asked the LAA about these mods. Part of the response I got is below. The LAA have not seen any photos or details of the build so only know it has clipped wings and slightly bigger ailerons. I apologise in advance to those of you in the US if the LAA seem to suggest that aircraft are not well built over there, this is their view, not mine....

[FONT=&quot]"Coming from the US Experimental category where such work is not a requirement, and amateurs are free to modify as they wish, it is virtually inconceivable that this work has been done to a standard that would satisfy UK requirements, or that if the aircraft were checked retrospectively, that it would be altogether satisfactory strength-wise. Clipping the wing span will have raised the wing loading and transferred a greater proportion of the load to the inboard part of the wing, upsetting the delicate balance of the load inboard and outboard of the interplane strut bracing points. And of course, the bigger ailerons will raise the wing torque, the effects of which are particularly difficult to analyse in a biplane where the wings are interlinked, and the interactions are complicated by stagger and sweep-back effects, plus of course, the stress-magnifying beam-column effects in the spars arising out of the combination of transverse aerodynamic loads and end load generated by the tension in the flying and landing wires.
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[FONT=&quot]Our business model does not allow us to spend huge amounts of our designer’s time trying to sort out this kind of issue, and the time that we have we naturally try to put toward the greater good by working on clearing new designs of aircraft for our members, or modifications that will have more general appeal amongst our membership. While we have a long but not entirely satisfactory history of imported amateur builts that are essentially ‘stock’, and with helping builders devise their own modifications from scratch in a viable manner, this significantly already-modified one-off aeroplane comes from, and very much belongs in, the US experimental category and trying to bring it into the UK’s regulated category would be like trying to push a square pin through the proverbial round hole. Regretfully we feel therefore that this is not a project that is viable to deal with as an LAA project. "
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Perhaps I should have just given up there but I have seen the aircraft and it is very well built indeed. The actual mods to the wings are not that great , the ailerons are one rib wider and balanced. I believe the wing is not unlike the Model 12 wing. The wing structure has been strengthened.

I understand that there are quite a few clipped wing Skybolts in the US and others have bigger ailerons or spades .

If I can present evidence that these exist safely that will help, but also I could perhaps do with the opinion of a suitably qualified engineer on the structural significance of these mods and I am happy to pay for such advice.

So if anyone could suggest such an expert or even let me know how many clipped wing Skybolts there are out there, operating without problem, that may help me to get the LAA to see this differently.

Thanks in advance

Jason
 

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