On the Bench 223b: David Merriman’s Von Braun Cargo Rocket part 1
Dennis Rodgick recently challenged me to mate this model rocket nose-cone with a little creativity from my end to produce a large scale model of the Cargo Rocket 3rd stage with attached cargo fairing. The upper unit is that model rocket nose cone outfitted with paper cutout of the 3rd stage engine and tankage section. The small rocket motor below is a quick assembly of the Strombecher/Glenco RM-1 moon rocket engine – which was supposed to be an identical unit to those that pushed the cargo, fuel, and passenger vehicles into orbit.
I consulted the book, The Exploration of Mars, authored by Von Braun some five years after his involvement with the Disney Tomorrowland episodes that presented his concepts for near Earth and planetary exploration. In one of the appendixes of that book he listed weights and measurements of all specific units that comprised his heavy-lift vehicles. From that listing I got exact measurements of the 3rd stage (its motor and tankage length and diameter) as well as the lengths for the dry-cargo and propellant/oxider cargo fairings. Perfect! Above is a study of model size to specific scales. As it turned out 1/32 was right on to the diameter of the nose-cone Dennis sent me. 1/32 it is!
Other books consulted were Ron Miller’s, The Dream Machines and the excellent work, Spaceship Handbook, authored by Jack Hagerty (though almost all of the illustrations are flawed, his text is simply wonderful: informative and relevant to the time in which the subject matter originated). Here you see arrayed around the mockup and little Strombecker motor buildup several shots of the Tomorrowland shows – I made good use of the recently offered DVD’s put out by Disney. Excellent stuff … first time I ever saw the RM-1 moonship segment in color!
The paper cutout was traced over a print taken off the TV screen – I think lens distortion extended things out too much longitudinally, have to squeeze everything back a bit … but that’s why I did the mockup: to check for eyeball accuracy. The little kit rocket motor assembly proved a wealth of good information; it was detailed right down to the corrugations on the expansion connections — and even featured an exhaust pipe for the turbine discharge, a point missed on Disney illustrations and even the big RM-1 model.
von Braun did the Disney work in the mid-50’s – about the time of the upper stage AGENA work carried out in aerospace land, initially in support of the CORONA spy satellite program. So, there had to be some cross-over between von Braun’s 3rd stage motor and the real AGENA motor. The AGENA, a restartable upper stage, was a sort of ‘bus’, intended to either shift orbit or to insert a payload into interplanetary orbits.
The Disney 3rd-stage and AGENA were upper stage workhorses which were turbo-pump fed, multi-start, gimbaled motors, with outrigger jets for fine velocity adjustments and attitude control. Anyone out there got good shots of an AGENA motor without protective fairings? I want to see its guts so I can get an idea on how cable runs and mountings looked on a contemporary of the mythical von Braun 3rd stage motor.
to be continued…..