LR-101 vernier Rocket Engine, and it’s interesting History
From Wikipedia:
Assembled in 1960, this vernier motor provides attitude adjustment during the rocket’s launch.
It has many of elements of the liquid fuel engines that later powered the Apollo and SpaceX rockets– with regenerative cooling of the nozzle, electric igniter, RP1 and LOX valves, and dual pistons for directional pointing.
Why I got interested in this motor:
I was just looking at ‘Cold gas thruster’ article, then this part caught my eye:
Vernier Engines[edit] : Larger cold gas thrusters are employed to help in the attitude control of the first stage of the SpaceX Falcon 9 rocket as it returns to land.[7]
So, I searched more about Vernier Engines, and found that amazing engine. Now, the thing that got me interested was that ‘NEMA’ motor looking linear actuator / piston thing.
Looks pretty sleek, and man I was surprised to see that back in the 1960, they had such organized wires / motor assemblies.
I mean, they DO look like stepper motors.
Oh wait, are they modified?
I got a lot of information from Steve Jurvetson’s Flickr. Lots of goodies!
MORE from Jurvetson’s Flickr comment :
And some spaceaholic details from the predecessor version:
“An LR101-NA Vernier rocket engine assemblage manufactured by ROCKETDYNE Corporation for installation onboard an Atlas SM-65 ICBM (Atlas “A”/XLR 89 NA-1).These engines were employed in various configurations to provide attitude (roll, pitch and yaw) control onboard the Mercury-Atlas, Atlas, Thor ICBM, Delta propulsion systems. A fixed-thrust, single-start, liquid bipropellant engine producing of maximum of 1000 pounds of thrust (nominal seal level), the engine design allows postoperative purging, regenerative cooling, thrust chamber gimbaling, and full-thrust runs of 325 seconds duration. It has a dry weight of 54 pounds and measures approx 28 x 27 ¼ x 20 inches (normal gimbaling arcs included). Designed propellant mixture is combination RP1 (highly refined liquid Kerosene) and LOX (liquid oxygen).
The engine consists of a thrust chamber assembly (a steel double-walled structure with a copper spiral regenerative cooling coils between the inner and outer walls), a pneumatically operated propellant valve with a valve position-indicating switch, an electrically fired igniter assembly, a pneumatically controlled oxidizer bleed valve, a fuel manifold pressure switch, a manifold gimbal assembly, propellant orifices, and pneumatic purge check valves. These components along with interconnecting electrical cabling and tubing assemblies are fixed in position on a welded tubular engine mount.
Gimbaling is facilitated via a pitch gimbal shaft, which provides for movement of the thrust chamber through a pitch-roll correct arc of 70 degrees on either side of the neutral position; and a yaw gimbal shaft which permits movement of the vernier thrust chamber through a yaw correction arc of 30 degrees (outboard) and 20 degrees (inboard) of the neutral position. In addition to performing the thrust direction gimbal function, the yaw shaft serves as a manifold for passage of fuel and oxidizer to the thrust chamber.”
And on a side view, with readings of 800 PSI for fuel and oxidizer, Part Number 133ED7, Serial Number 295, Assembled 9/60, NAA Serial Number N0148C Spec -1
Unfortunately, I couldn’t find out whether they were actually electrically controlled.
Story of Robert Truax
So there was this guy back in 1970-ish era, who built a rocket with these motors, lol.
And as I was reading more about him:
LOL, turns out, with a dedicated ‘private space tourism’ plan in mind, he bought these LR101 vernier engines, each for 25 Dollars!!
Plus, he seems to be a really avid aerospace / rocket enthusiast. About the X-3 Rocket :
The X-3[14] Volksrocket (other names: Arriba One, Skycycle X-3) was a reusable space tourism rocket planned by Robert Truax after Evel Knievel provided a $1,000 research grant[14] for a pilot study. Truax was looking for volunteers with enough money to help fund the effort and who wished to fly aboard his rocket. He got thousands of volunteers, but few of them had the financial resources. One person selected to fly in the rocket was engineer Jeana Yeager, who worked for Truax Engineering. Peruvian-born Daniel J. Correa was at one point announced as the first pilot.[15] Among others who offered some financing and who went through some of his training were Ronald Beller, a pilot from Kentucky, Martin Yahn, Ray Upton, and Fell Peters, all of southern California. Ultimately, no one flew in the Volksrocket.[16]
The rocket used surplus components and was tested through 1991.
But there’s more! Steam rockets!
Truax also designed the Skycycle X-2, which he unsuccessfully tested on April 15, 1972 and June 24, 1973, and which Evel Knievel unsuccessfully used at the Snake River Canyon in 1974.[2]
One interesting thing is that I’ve seen this canyon jump / steam rocket story back then. But now, I know that Robert Traux was the one who designed this X-2 craft(with parachutes!), and that he also was a pretty interesting person. Who dreamed about low-cost spacecraft and personal space tourism, etc.
Snippet from the article(1990). In there, Truax’s enthusiasm is apparent. “We’ve got to stop thinking we’re helpless. Hell, we knocked off the moon in ten years.”. WHAT A LEGEND!
Also, each candidates for the private astronaut program had their own fascinating stories.
Including, ‘Dan Correa’, who sold a lot of ‘Tortillas’ for funding. And eventually took over the company he worked at(after getting paid in stock for his ‘commission based income’).
He designed / manufactured at ‘Tortilla Steamer’, that was a niche product for the market, but had the steams / water messing up the electronics, and eventually lost his house, etc. So eventually, it came to an end.
But I do find this story so fascinating though. 1979, and selling tortillas for going up to space! What a story!
Some more snippets!
‘Martin Yahn’, who wasn’t wealthy enough to pay $100k, had a hell lot of a passion.
And that ‘Static fire’ tests of LR101 vernier engines sounds so awesome.
It seems apparent that firing those engines weren’t the critical problem? I’m fascinated because it involves LOX, cryogenics. And I wonder how Truax managed to get all those necessary equipment!
p.s. Website with a lot of interesting info about this engine :
