kit vs. plan: difference in engineering?
05-28-2002 | 05:12 AM
#1
Thread Starter
kit vs. plan: difference in engineering?
Hi Maarten --
I have looked at many and the changes are usually small or none.
The changes always make the design better, but who they make it better for varies... for instance it's common for changes to made that make the plane easier to build or easier to align, and I don't think those changes hurt anything. Sometimes, though, the design is made stronger by adding weight (I think that the once very popular PT-40 was a good example of this) and sometimes it's made easier to fly by adding stability (the Spirit is a good example of this one).
Adding weight to a beginner's trainer might make it survive a crash better (though I personally do not think so), but it will definitely make it stall at a faster speed and make it more likely to crash, so I think it is less able to do its job as a trainer. Stabilizing a thermal duration type sailplane might make it easier to fly, but it makes it harder to find a thermal with, so it's also less able to do its job. (Let me also say that I'm not trying to defame either of these: both the PT-40 and the Spirit are very good airplanes even as kitted).
Of course I've also seen scale kits that were made more stable than their prototypes and really benefitted from it. As a whole, the changes I've seen that affected flying were almost always toward straighter, more stable, and stronger. That usually is a good thing, but usually has to be judged against some penalty like added weight.
I have looked at many and the changes are usually small or none.
The changes always make the design better, but who they make it better for varies... for instance it's common for changes to made that make the plane easier to build or easier to align, and I don't think those changes hurt anything. Sometimes, though, the design is made stronger by adding weight (I think that the once very popular PT-40 was a good example of this) and sometimes it's made easier to fly by adding stability (the Spirit is a good example of this one).
Adding weight to a beginner's trainer might make it survive a crash better (though I personally do not think so), but it will definitely make it stall at a faster speed and make it more likely to crash, so I think it is less able to do its job as a trainer. Stabilizing a thermal duration type sailplane might make it easier to fly, but it makes it harder to find a thermal with, so it's also less able to do its job. (Let me also say that I'm not trying to defame either of these: both the PT-40 and the Spirit are very good airplanes even as kitted).
Of course I've also seen scale kits that were made more stable than their prototypes and really benefitted from it. As a whole, the changes I've seen that affected flying were almost always toward straighter, more stable, and stronger. That usually is a good thing, but usually has to be judged against some penalty like added weight.
