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

AeroTech Motors Used in Setting New Tripoli Altitude Record
June 24, 2004
Web posted at: 5:30 PM EDT
(ROL Newswire) -- The AeroTech division of RCS Rocket Motor Components
(RCS), Inc. is pleased to announce that AeroTech high-power motors were
used exclusively by AERO-PAC prefecture member John Rockdale in setting
a new Tripoli Rocketry Association record for 'M' class altitude. John
flew his "Tupelo" rocket at the Mudroc launch held at Nevada's Black
Rock Desert on Saturday June 19, 2004. The flight was also a record for
all Tripoli motor classes. According to the on-board RDAS GPS
instrumentation, John's rocket achieved a maximum altitude of 44,958
feet (13,707 meters) AGL. Both stages were recovered intact.
Specifications of the rocket are as follows:
Booster: 75mm custom Dynacom
Booster motor: AeroTech M1315W reloadable
Booster liftoff wt.: 25.0 lb
Sustainer: 54mm ShadowAero "Shock Value"
Sustainer motor: AeroTech K250W single-use
Sustainer wt.: 9.5 lb
Rocket length: 144"
Staging coast time: 4 sec.
Booster electronics: ALTACC plus Adept ES231MH stager
Sustainer Deployment: Rouse-Tech CD-3 CO2 device
Instrumentation: RDAS "Kompakt" with GPS expansion board
Tracking: Walston transmitter & receiver
Apogee as determined by the RDAS occurred at T+54 seconds. The sustainer
was recovered 2.8 miles from the launch site. The paint near the nose
cone tip was softened from aerodynamic heating and had flowed down the
cone for a length of about 2".
More information can be found on John Rockdale's website at
formatting link

AeroTech joins AERO-PAC in congratulating John on his excellent
record-setting flight!
Source: RCS Rocket Motor Components (RCS), Inc.
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ROL News
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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.
Reply to
Chad L. Ellis
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 50% and 0 points with a decreasing load to check for hysteresis.
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:
Reply to
David Schultz
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
Reply to
Jerry Irvine
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.
Reply to
Phil Stein
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 only claim to calibration made by Mark Clark was the 75 pound weight.
Phil Ste> 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. > >
Reply to
David Schultz
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.
Reply to
Dave Grayvis

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