The wind variations I tried to account for by both NOT adjusting the rod angle during the entire set of flights and, as I noted before, intermixing the various ages. If you look at the flight numbers on the first column you can reconstruct the actual order of flights. The winds that day were quite light, which was about as ideal as it gets for doing something like this.

I also cleaned the rod after every third flight, though I probably should've done it every time.

I'm not sure about the 1-2% altimeter error. I flew the same one on all flights...and these devices are quite good these days.

But I agree that this was not enough flights to prove anything definitively. What it disproves, I think, is the idea that old motors are significantly better than new ones. The idea that was advanced in that other thread was that they are just not as good as they used to be, and I don't think that is true.

I would rather say that the oldest motors had the most accurate delays. I had, anecdotally, noticed that older motors (and by this I mean those from the 1990s) tended to run short delays. These data tend to agree with that as well.

I think AltimeterThree reports burn times to the nearest 0.05s,.

For what it's worth, I was out with the same model today and flew it twice off a mini (10mm) rail using two more B6-4s from that 2019 bulk box. Both flights were toward the upper end of the range from the data I posted, that that is confounded a little by using a different, lighter altimeter countered by the added weight of the rebuild after the last flight lawn dart from the data posted above.

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Bernard Cawley
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