ROL NEWS--AeroTech Motors Used in Setting New Tripoli Altitude Record

Ditto!

Check out the hardware list!

So, where did he get the K 250 from.......Under a rock?

JD

Don't ask, don't tell.

I burned one in January 2004. Unfortunately, my last one :-(

Tom

Is it a full K?

It was submitted as the K230. TMT said it was an L330 which is way off and they requested another motor to test again. They were sent the motor months ago but no results. AT gets a few new motors certified asap but Bob is still waiting. The numbers between the K250 and the Ellis version were almost identical.

Welcome to the machine.

Interesting. I posted a rant on TMT's pathetic load cell calibration over in TRF a while back after the L1120/M1297 change.

Mark Clark claimed (on TRF) that the test stand was "calibrated" using a 75 pound weight prior to the test. This was the only claim made for calibration.

All serious users of load cells send their cells to a calibration lab for NIST traceable calibration on a regular schedule. Once a year or so. This calibration is done at a minimum of three points: zero, 50%, and 100% of rated load. This verifies the sensitivity and linearity of the cell. They also usually repeat the

TMT "calibrated" at zero and 75 pounds. (How does TMT know that it is 75 pounds? A bathroom scale doesn't count.) The M1297 thrust curve shows that most of the time it is well in excess of 75 pounds thrust. (starting around 400) Even if the load cell were linear within the 0-75 pound range checked (something that was not established), nothing is known about its behavior above 75 pounds. It was simply assumed to be linear.

Of course 75 pounds is equivalent to 333 Newtons so the K230 should have been within the "calibrated" range. But if it has anything like the regressive curve of the Aerotech K250 then it exceeds 75 pounds for quite a while.

I would like to think that the delay in retesting is the result of TMT finally sending the load cell to a calibration lab.

Chad L. Ellis wrote: > It was submitted as the K230. TMT said it was an L330 which is way off and > they requested another motor to test again. They were sent the motor months > ago but no results. AT gets a few new motors certified asap but Bob is still > waiting. The numbers between the K250 and the Ellis version were almost > identical. >

I used to calibrate test stands that way in 1974-1984. Chuck Rogers copied a lot of what I didin his motor test efforts (then excluded me from them).

I use ONLY professionally calibrated load cells now. They are only 20% more money and a whole bunch more accurate. But even if they were three times the money, one would think a "motor testing agency with force of law" would at minimum use them.

But not at TRA!!

Ha!

Their failure is your cost and your delay.

At least they didn't "lose" it and then it shows up later at a Vegas sport launch!

Of course!! AT and TRA were in bed together on many vendor "delays" and ATF pokings in the eye, and insisting on ATF permits for rocketeers.

The collusion is harmful to everyone.

JERRY

I didn't see the discussion on TRF. It does make sense to have the load cell calibration checked. Do you know if it ever has been checked?

One thing I've noticed is that several AT motors tested similarly and IIRC, they used the same propellant. I wouldn't rule out the possibility of a change in process or formulation causing this.

Don't ask, don't tell.

I would.

Jerry

How surprising!

Gary claimed that no changes had been made to the L1120. Two stable mates of the L1120 (K560, L850) were recertified last year and did not show a comparable increase in performance. In fact they showed a slight decrease.

As I said, the > I didn't see the discussion on TRF. It does make sense to have the

In 1974 jerry was 16! What exactly did Chuck "copy" from you? Be specific.

jerry, if you don't make motors why would you need a test stand?

Post a picture of you test stand/load cell.

You have no load cells. Just a HUGE debt load.

It sounds like a valid point. If I see the TMT guys at LDRS & I remember, I'll ask about it.