speed poll

[cherokeej]

kind of a blanket statement don't ya think?

I think the point about posting or not posting data was to eliminate all the "imaginary" results. Like "rasaero said I flew mach3" or "rock sim said it flew mach4"

Perhaps saying it happens "all the time" is a bit over the top. But they DO screw up. More often than we would like.

I think it would be interesting to do a study.

For ALL flyers, how many accelerometer based flights in a year, and out of that, what percentage was ridiculously unrealistic? Like a 3 grain 98 going almost 100K at M3+...

BTW... That same bird flew again that very day, and the files from both accelerometers were back in line with the real world. Change over 11K @ .9 Mach. So accelerometers DO experience the occasional unexplained glitch.

As for ppl posting sim results... You can ask that sims be excluded, I think most folks will honor that request. But some won't. When they tell you it's a sim result, you know to exclude that from your data. And when they tell you a 2 second 54mm K did 48000 feet, well...

 

[patelldp]

My personal fastest success... 54mm MD on a Rx L1771R... M2.86.

Can you elaborate a little on this? It's fine if you don't post the file, but that seems pretty quick. Motor case, rocket length, carbon vs. glass? I've flown my Mongoose 54 without the payload section twice with a 2550 (Kosdon Fast Clone, 7:1 Blue) and never cracked Mach 2, both files have been attached in this thread.

Weights were around 9# for both flights.

 

[cherokeej]

All carbon MD, 2.25 pounds prepped and unloaded. Taste over 10# loaded. 100G GWiz MC on board.

35.5" case, containing 10 grains (32") of WR, 3/4" cores in the top 7 grains, 7/8" cores in the lower 3, all grains liner-bonded, and a .688" nozzle, 1.9 second burn. Change over 22K. 1.9 seconds is rather inefficient use of >3500 Newtons.

Work continues on a moon-burner for that case. Elusive booger, but we're trying.

 

[KennB]

The fact that I am on the earth means I am moving about 66,660 miles per hour around the Sun - also since I live at about 40 degrees latitude I am moving about 795 mph around the planets axis

Let's not forget that the Sun is in a spiral arm of the Milky Way pivoting around its center and that the galaxy is moving away from most everything else in our universe. Whew, it makes me dizzy thinking about it. :eyepop:

I was going to stay away from this thread especially since some toxic elements have seeped in but I couldn't help but continue with the wise@$$ tangent replies some have posted here. Good work all. (Plus it gives me another post toward my 25 for my harness entry).

 

[cherokeej]

I should mention... That was a modified version of WR. Good dose of AP90 in there for a somewhat faster burn. Wanted to get it out of the pipe quickly.

 

[troj]

Flight data means exactly squat. Accelerometers screw up all the time.

Not anywhere near as often as sim software produces highly suspect results.

-Kevin

 

[littlemisterbig]

Speaking of accelerometers, check this out! https://www.feretich.com/rocketry/Resources/ASU/index.html