A multi-staged vehicle with peak sensor

The following is a report written in February of 1985 by RRS members George Dosa and Frank Miuccio. The report details a three-stage rocket with several illustrations. For the sake of preservation, this report is reproduced in this article.

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A MULTI-STAGED VEHICLE WITH PEAK SENSOR
by Frank Miuccio and George Dosa

The purpose of this report is to document the building and testing of a three stage vehicle with a peak sensing device. Short betas were chosen for the 1st and 2nd stage and a short Mark Series for the 3rd stage. The peak sensor will be a photocell intended to detect the change from sky to ground and activate a parachute system. The 2nd and 3rd stage will be fired using inertia switches and a unique 3rd stage interlock system. A minor test will be of a passive sound emitter on the 2nd stage.

Also, (in this project) going to see if white, black or stainless is the best color to see (when spotting the rocket).

NOTE:
The report has sketches of the individual stages of the three-stage rocket and their interconnections.

first stage, shortened RRS standard beta, micrograin

2nd stage – shortened standard beta, micrograin rocket

3rd stage – Mark series rocket

556 timer chip, schematic

Sketch of the 3-stage rocket design

Second to third stage coupler design – sketch

Photo of the 3-stage rocket design

[more images and details to come, work in progress]

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For questions, contact the author, Frank Miuccio.
vicepresident@rrs.org

or the RRS secretary
secretary@rrs.org

MTA launch event, 2018-06-07

The RRS held another smaller launch event at our private testing facility (MTA) in the Mojave desert on Thursday, June 7, 2018. This was a special event for the RRS members from the former Chaminade High School Rocketry group led by Jack Oswald. They have been working hard on their solid motor design. After a successful test series on a single 6-inch Bates grain, they moved up to a vehicle sized test with multiple six-inch grain modules installed. Dave Crisalli and Osvaldo Tarditti were available to assist in the loading and installation process making ready for testing. The vehicle static fire test was oriented nozzle up with a load cell at the bottom of the frame secured to the vertical test stand at the RRS MTA.

The static fire testing was for a 10,000 lbf-sec flight motor. The motor was expected to perform at 1500 psi, produce over 2+ tons (>4000 lbf) of peak thrust, and burn its 43 lbs of composite BATES grains in approximately 3 seconds.

Osvaldo had video of the firing where we got the still photos below. Osvaldo will bring the video footage to the meeting tomorrow on Friday, 6/8/2018, where everyone can see what may have happened.

Vertical static fire of a solid rocket motor at the RRS MTA, 06-07-2018

The solid motor started okay. The nozzle plume looked good for the first few moments.

Jack’s motor starts off just fine. A nice nozzle plume is evident.

Unfortunately, shortly after start, about 2 seconds into the burn, the pressure climbed substantially to 2300 psi causing a nozzle failure and subsequent burnout.

It looked like something disturbed the flow in the frame just before the huge fireball and the disintegration of the nozzle

After the nozzle failure, the solid motor spews chunks of fiery propellant until it fully burned out.

In the coming months, Jack’s team will make another motor reducing the Kn factor and significantly reinforcing the nozzle design to carry through with their plans of launching a boosted dart to an altitude of 150,000 feet sometime this year. This is still an impressive accomplishment and with some perseverance, success will come. More details to come as things proceed.

During the June 7th event, Osvaldo took some time to search down-range for rockets with his extractor tool. As luck would have it, he found one of the RRS standard beta rockets launched by UCLA in 2017. It was found about 3000 feet downrange which isn’t terribly far away. The winds must have been very favorable to allow the beta to plant itself much closer to the launch site. From the photo, you can see that this RRS beta had a fin-can type of fixture at the tail which is easier to manufacture.

Beta planted 3000 feet downrange from the launch rails, straight west more or less

The convenience of pulling the rocket straight from the ground with the manual winch is tremendous, but the method often shears off the payload tube in the hole. Shoveling does have the advantage of removing most if not all of the parts if one is inclined to spend the hours necessary to dig four feet below the surface. The payload tube from the beta unfortunately was not extracted with the propellant tube. Osvaldo will bring the beta to show everyone at the meeting tomorrow.

Osvaldo lifts the beta rocket from out of the desert floor

We’ll have our monthly meeting (every 2nd Friday of the month) on June 8th at 7:30PM sharp. Please stop in!