Decertification is an arbitrary rule installed to deal with one bad example from the early 70's. That one bad example could have been decertified without automatically decertifying all motors. This is a stroke of the pen change that has been proposed to but not adopted by NAR and by reference NFPA and TRA and possibly CAR.

This is a respected group of folks. How about a letter writing to president@nar.org to seek this sensible and needed change.

The strongest reason to change the rule is in some states a "decertified motor" becomes a "destructive device" despite common sense, physics, and contrary legal treatments in other laws, regulations, and guidelines.

Jerry

The most common reason has been beaten into glue in this thread... http://www.oldrocketforum.com/showthread.php?t=8925


Bill

Ignoring facts to reinforce the status quo may qualify as beating a dead horse into glue to you, but it looks more like a conclusion supported by whatever argument that is needed to support the status quo and that pre-conceived conclusion.

The very idea of any decertification in any other industry or product line would require a court order to accomplish, which is both difficult and expensive.

Jerry

Back when Estes was making the Maniac kit (Same as the Eliminator now just different colors) I modified several with 29mm motor mounts. I flew them on AeroTech F25-9W motors. I 'landed' one of my modified Maniac models in a tree at NARAM-41.

At NARAM-42 I had a new Maniac kit built for use with a 29mm motor. This time, however, it would be no whimpy flight. ;)

Matt Steele gave me a Dark Star F62-9 motor to use in the model. The F62-9 was NAR certified at the time but was not put into mass production by Estes. Matt also had a Dark Star G70-10 I could fly if my Maniac survived the F62-9 flight.

The Maniac was prepared with the F62-9 and placed on the launch pad. At ignition, the model lept into the sky and promptly disintegrated. I watched the video I took of the flight recently and it appears the body tube failed.

I recovered the 'pieces' and discovered that the leading edges of the fins on the molded fin can had broken off or split. I guess I was pushing Max-Q for that part. :eek:

Or, in other words Bob, you exceeded the speed of plastic?! ;)

The circa 1999 F62 uses the exact same grain geometry as its long time predecessor the U.S. Rockets F40/F80/F160. EX guys can do the math on this one. 2 grains 1.25" long, 5/16" core and a propellant OD of 0.96". Almost flat shape. The propellant used in the F62 was developed by Scott Dixon of Vulcan and had a very high ISP for its size and good ballistic properties. The burning rate and time was right in between our circa 1988 F40/F80 motors. The total impulse was almost exactly 80N-s.

Jerry

String Test! of the "semi-scale" 1340
 

:D I went old school...a tiny pat of clay with a G 80 and it looks good with a "string test"....guess we will see what happens when the wind dies down....Will take before and (hopefully) after photos with the results