Malemute (single-stage version)

[blackshire]

Hello All,

This morning I found that the Thiokol Malemute (which has been used as the upper stage of the Nike-Malemute, Terrier-Malemute, and Terrier-Improved Malemute sounding rockets for decades) was also flown at least twice as a single-stage rocket in 1976, in order to test the motor in a spinning flight regime. Below are two links to scale data and historical information on these two NASA test vehicles--as well as a color photograph of a similar U.S. Navy single-stage Malemute II (used as a radar target in a "Slugger" ballistic missile defense test) at launch in 1999 (that photograph is also attached below).

The two NASA Malemute test vehicles were launched at Sandia's Tonopah, Nevada rocket range, and they utilized an unusual recovery sequence--in each flight, three of the rocket's four fins were blown off after motor burnout to make it tumble, to facilitate recovery closer to the launch site. The one-finned spent rockets didn't tumble until they were on the descending legs of their trajectories, however, which resulted in peak altitudes of over 140 km instead of the predicted 44 km! Here are the links:

http://www.designation-systems.net/dusrm/app4/other.html
[NOTE: the Malemute photograph is near the bottom of this web site's "screen-page."]

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19780016341_1978016341.pdf
[NOTE: The Malemute general arrangement dimensioned drawing is on page 21 of this report, and a dimensioned drawing of the Malemute rocket motor in on page 14.]

I hope this material will be useful.

[Bill]

The two NASA Malemute test vehicles were launched at Sandia's Tonopah, Nevada rocket range, and they utilized an unusual recovery sequence--in each flight, three of the rocket's four fins were blown off after motor burnout to make it tumble, to facilitate recovery closer to the launch site. The one-finned spent rockets didn't tumble until they were on the descending legs of their trajectories, however, which resulted in peak altitudes of over 140 km instead of the predicted 44 km!


Hmmm...mission points for shedding fins...


Bill

[blackshire]

Hmmm...mission points for shedding fins...


BillThat's what I was thinking--the motor mount could be free to partially eject rearward perhaps 3/4" or so before stopping (using an internal "sleeve tube" around the outside of the movable motor mount tube to direct the ejection charge forward in the normal way). The movable motor mount would retract pins that would hold the three "flyaway" fins in place during ascent, allowing small springs (which might not be necessary) to pop the fins off.

[Bill]

That's what I was thinking--the motor mount could be free to partially eject rearward perhaps 3/4" or so before stopping (using an internal "sleeve tube" around the outside of the movable motor mount tube to direct the ejection charge forward in the normal way). The movable motor mount would retract pins that would hold the three "flyaway" fins in place during ascent, allowing small springs (which might not be necessary) to pop the fins off.


Though I would tether them so they do not get lost. Use clear fishing line for that?


Bill

[blackshire]

Though I would tether them so they do not get lost. Use clear fishing line for that?


BillYes, I'd probably use thin monofilament fishing line. Depending on the scale, though, since the Malemute's fins are (if memory serves) "single-wedge" in cross section like the Aerobee 350's fins, expendable "flyaway" fins built-up from card stock might be practical for flying in actual contests, to ensure getting as many flight points as possible. (The Aerojet Astrobee F would also be a candidate for this, because the first test round was intended to jettison all four of its fins to facilitate recovery of the spent motor for post-flight inspection. The fins' explosive bolts failed to fire and the motor streamlined in, causing its parachute to shred due to the high descent velocity.)