Atlas Engines

[HerobrineLiu]

Hello everyone!

I had extra time on the train, so I decided to read some pages on Atlas Missiles. The page refers to the engines as B-1 B-2 and (I’m assuming, because the Atlas had 3 engines) probably B-3. After an extensive search, I was not able to find what these designations actually mean and which engines they correspond to. Could I get some help? P.S. I was informed that only the Atlas B used explosive bolts to jettison the booster skirt. What is/are the other method(s) of doing so?

Thank you!

[Bill Phil]

Which article?

[p1t1o]

On 10/19/2018 at 9:25 PM, HerobrineLiu said:

Hello everyone!

I had extra time on the train, so I decided to read some pages on Atlas Missiles. The page refers to the engines as B-1 B-2 and (I’m assuming, because the Atlas had 3 engines) probably B-3. After an extensive search, I was not able to find what these designations actually mean and which engines they correspond to. Could I get some help? P.S. I was informed that only the Atlas B used explosive bolts to jettison the booster skirt. What is/are the other method(s) of doing so?

Thank you!

Im guessing you were reading the wiki?

Clues to be found in this document attached there:

http://www.dtic.mil/dtic/tr/fulltext/u2/833337.pdf

 

I think B-1 and B-2 refer to "booster 1" and "booster 2", with the third engine being termed "sustainer".

 

 

And from the Atlas-B wiki:

"The booster section would then be released by a series of hydraulic clamps (aside from the early test model Atlas B which used explosive bolts) and slide off the missile."

 

Google (and CTRL-F) is your friend

 

[HerobrineLiu]

14 hours ago, p1t1o said:

Im guessing you were reading the wiki?

Clues to be found in this document attached there:

http://www.dtic.mil/dtic/tr/fulltext/u2/833337.pdf

 

I think B-1 and B-2 refer to "booster 1" and "booster 2", with the third engine being termed "sustainer".

 

 

And from the Atlas-B wiki:

"The booster section would then be released by a series of hydraulic clamps (aside from the early test model Atlas B which used explosive bolts) and slide off the missile."

 

Google (and CTRL-F) is your friend

 

Do you know how they differentiated between boosters 1 and 2?

(I have not yet read the document so I don't know if it answers it but I have Latin homework)

[Ultimate Steve]

56 minutes ago, HerobrineLiu said:

Do you know how they differentiated between boosters 1 and 2?

(I have not yet read the document so I don't know if it answers it but I have Latin homework)

If you have an image with the engine diagram and the rest of the booster in the same shot, you can tell them apart because the fuel ducts on the Atlas exterior are asymmetrical.

[HerobrineLiu]

yeah

8 hours ago, Ultimate Steve said:

If you have an image with the engine diagram and the rest of the booster in the same shot, you can tell them apart because the fuel ducts on the Atlas exterior are asymmetrical.

Yeah but which ones is the "B-1" and which one is the "B-2" engine? 

[lrd.Helmet]

B1 and B2 would probably be the left and right engine respectively. However, then the question would be what is the left or right on a rocket?

[p1t1o]

@HerobrineLiu

Dude, flick through that document I linked, theres a diagram on p118. Took me less time to find than to type this comment

 

[DerekL1963]

4 hours ago, lrd.Helmet said:

B1 and B2 would probably be the left and right engine respectively. However, then the question would be what is the left or right on a rocket?

More accurately, they would probably be the 90 degree and 270 degree engines (or 0 and 180) - measured clockwise from a defined zero point as seen from the nose.  (At least that's how US SLBM's work.)

Even if they did call them "left" and "right", that's going to be in relation to a defined position.

[HerobrineLiu]

4 hours ago, p1t1o said:

@HerobrineLiu

Dude, flick through that document I linked, theres a diagram on p118. Took me less time to find than to type this comment

 

Sorry  I started reading the thing instead of looking for an answer. 

[Atlas LV-3B]

On 10/19/2018 at 4:25 PM, HerobrineLiu said:

Hello everyone!

I had extra time on the train, so I decided to read some pages on Atlas Missiles. The page refers to the engines as B-1 B-2 and (I’m assuming, because the Atlas had 3 engines) probably B-3. After an extensive search, I was not able to find what these designations actually mean and which engines they correspond to. Could I get some help? P.S. I was informed that only the Atlas B used explosive bolts to jettison the booster skirt. What is/are the other method(s) of doing so?

Thank you!

No. You would need the explosive bolts. You could test out other ways if you wanted to, however this is expensive to do so since you’d have to launch several other rockets. Also. The Designation for the rocket you are referring to is call the Atlas LV-3B. 1b and 2b being the more ICBM and test vehicle variants.

[Ultimate Steve]

On 10/26/2018 at 3:49 PM, Atlas LV-3B said:

No. You would need the explosive bolts. You could test out other ways if you wanted to, however this is expensive to do so since you’d have to launch several other rockets. Also. The Designation for the rocket you are referring to is call the Atlas LV-3B. 1b and 2b being the more ICBM and test vehicle variants.

From Wikipedia:

Quote

At staging, the booster engines would be shut off and a series of mechanical and hydraulic mechanisms would close the plumbing lines to them. The booster section would then be released by a series of hydraulic clamps (aside from the early test model Atlas B which used explosive bolts) and slide off the missile.

 

[DDE]

OP, your assumption appears erroneous. There's no B-3, Sutton - who built the damn things - identifies the sustainer engines as MA-1 through MA-5A while the boosters are B-1 through B-2C.

I'll haphazardly copy-paste the chunk of the book for your perusal.

Quote

The preliminary design of the engines for the Convair ATLAS ballistic missile was started in 1952 and was unique. The author's engineering group went through several iterations and discussions with Convair, the prime contractor, and the Air Force in arriving at the preliminary design. The two booster
engines of 150,000 lb thrust each were mounted in a ring or doughnut-shaped structure at the missile's tail, and this structure was dropped from the flying vehicle after booster engine cutoff at about 150 s. The sustainer engine with 60,000 lbf (located in the center of the aft end of the vehicle) is also started at
launch, but runs continuously for a total of about 310 s. Figure 7.8-5 shows a test of this three engine configuration. This one-and-one-half set of stages was selected in part because Convair, the vehicle developer, and Rocketdyne were not sure at that time if altitude ignition of a sustainer could be reliably achieved. Detail design started in late 1954. The total three-nozzle thrust of 360,000 lb at sea level (about 414,000 at high altitude) was increased in steps in the several subsequent modifications and in uprated versions of this engine until it reached an altitude three-nozzle thrust of 564,000 lbf as shown in Table 7.8-1. The altitude specific impulse reached 309 s (at 84,000 lbf thrust) for the sustainer engine. TVC during the booster flight was provided by the two gimbal-mounted large booster engines. During the sustainer-only portion of the flight, the roll control was provided by two small regeneratively cooled
small hinge-mounted TCs of about 1000 lbf thrust each. They received propellants tapped off the main sustainer engine's TP. A similar roll control scheme was used in the Thor missile, and it is shown in Fig. 4.6-3 and 4.6-4. The propellant tanks developed by Convair had very thin walls and had to be inflated by gas pressure at all times (during storage, launch preparations, or road transport) to prevent buckling or collapse. This also caused some extra steps in the vehicle transport, launch operating sequence, and in the engine installation.

The new turbopump for the booster stage engine, seen in Fig. 4.4-2, featured an alloy steel turbine, connected to the propellant pumps through an oil-lubricated gear transmission case. The turbine ran at a higher shaft speed than the two pumps, which were on one common shaft. In prior engines a 90% monopropellant hydrogen-peroxide GG was used, and its maximum flame temperature was limited to about 1360°F. With a bipropellant GG the warm gas temperature can rise quickly (by 100 to 300°), if the mixture ratio shifts even only a percent or two. A high-temperature turbine material and an adequate margin are therefore necessary. In later versions of this TP, with other large LPREs some or all of the lubricating or cooling oil was replaced by kerosene fuel, and General Electric replaced the oil with grease in one of its gear cases (Chapter 7.3). The Atlas TP was an uprated version of the Navaho TP. The turbine was driven by a gas generator using the same propellants as the main chamber, but at a fuel-rich mixture resulting in a gas at about 1000 to 1350°F. The gear case allowed the pumps (about 5000 rpm) and turbine (about 30,000 rpm) to operate at different shaft speeds; the resulting higher efficiencies reduced the amount of propellant needed by the gas generator and raised the specific impulse by perhaps 1 or sometimes up to 3 s (Ref. 12). Early versions of this turbopump and the TPs of other early engines did not have inducer impellers, which provided a margin for avoiding cavitation and allowed a somewhat higher pump speed of the main TP. An inducer impeller is usually an axial-flow low-head pump, and an example is shown in Fig. 4.4-8. Very similar TPs with inducers were used on later versions of the Atlas, Thor, Jupiter, and on all of the versions of the H-l and the RS-27 engines, and these engines are discussed later. Early versions had two auxiliary pumps attached to the gear case, an oil pump to cool and lubricate bearings and gears, and a hydraulic oil pump to supply pressurized oil to gimbal on hinge actuators and to some valve actuators. The gas generator, which supplied the TP with chemically heated gas, is shown in Fig. 4.5-6. In one version of the Atlas propulsion system, the two TPs for the booster engines were located next to each other and supplied with warm gas from a common
single-bipropellant GG.

Although the initial Atlas engine designs had conical nozzle-exit cones, they were soon changed to a bell-shaped nozzle exit beginning in about 1958. This specially contoured nozzle exit was believed to have been an original contribution of Rocketdyne to the U.S. technology of propulsion. Figures 4.3-5 and 7.8-2 show large early conical nozzle exits of the Thor TC and the Navaho, but Figs. 7.7-18 and 7.8-13 show the large Titan TC and the J-2 engine with typical bell-shaped nozzle exits. The genesis and advantages of bell nozzles are explained in Chapter 4.3. In fact Rocketdyne had the first production thrust chamber with a tubular cooling jacket for the chamber and with a bell-shaped diverging nozzle. Rocketdyne had experimented with nickel, inconel, and stainless-steel tubes, developed the process for tapering the straight tubes, bending them into the contour of the combustion chamber and nozzle, pressing and forming the tube cross section into a nearly rectangular shape, and then brazing the tubes together in a special furnace. Different brazing compounds had been investigated.

The start features were different in the five models of the Atlas LPRE, each with a somewhat different vehicle stage. In all models the two booster engines were dropped off. In the MA-1 model the starting was accomplished with pyrotechnic igniters in both TCs and both GGs, which were supplied through two onboard pressurized propellant start tanks. The MA-1 sustainer engine had pyrotechnic igniters in its main TC, its GG, and the two small vernier thrusters, which were used for roll control. In the MA-2 and MA-5 models slugs of a hypergolic start liquid fuel ignited the initial flow in all five thrust chambers, but they retained the pyrotechnic igniter in the three GGs. The Atlas MA-3 was equipped with solid-propellant start cartridges for igniting the initial flow to the three GGs and for starting the spin-up of the turbines; hypergolic start fluid ignition continued in all five TCs. In the last Atlas version, the MA-5A, the start tanks, and their pressurizing gas systems were on the ground, with two pyrotechnic igniters in each GG and hypergolic start fuel in the three main TCS. There were no small hinged vernier thrusters in this model. However the sustainer stage of the MA-5A had a separate hydrazine monopropellant multithruster system for roll control during the main engine's operation of the sustainer engine, and it was also used for other maneuvers.

The Atlas missile was the first U.S. ICBM and was operational in the U.S. Air Force between 1960 and 1965. Several versions of this Atlas engine also served in propelling satellite launches for many military and space exploration payloads.5"-8 This included the Surveyer, Pioneer, or Intelsat satellites. A takeoff of an Atlas SLV is shown in Fig. 2-9. Different versions of the Atlas SLVs had various upper stages, including Agena with a LPRE from ARC and Centaur (LOX/LH2) with two LPREs from Pratt Si Whitney. The ATLAS engines drove the booster for the Mercury manned spaceflight program. It was an active rocket engine program for 46 years, in production intermittently between 1956 and 1996, and 571 engine sets (consisting of two boosters and one sustainer engine) had been delivered up to December 2002. There were 24 failures or malfunctions during flight out of 1713 flying engines, which were attributed to the propulsion system, but only some of these caused an abort of the mission. This gives an average overall engine reliability of about 0.97. Most of the flight failures of the engine occurred during developmental flights, and the most recent series, the MA-5A, had no engine flight failures.

 

On ‎10‎/‎24‎/‎2018 at 7:40 PM, DerekL1963 said:

More accurately, they would probably be the 90 degree and 270 degree engines (or 0 and 180) - measured clockwise from a defined zero point as seen from the nose.  (At least that's how US SLBM's work.)

Even if they did call them "left" and "right", that's going to be in relation to a defined position.

Rocket coordinate systems are always more or less arbitrary - and often so hard to determine the manuals dedicated a whole figure to them.

Edited November 9, 2018 by DDE

[DerekL1963]

1 hour ago, DDE said:

OP, your assumption appears erroneous. There's no B-3, Sutton - who built the damn things - identifies the sustainer engines as MA-1 through MA-5A while the boosters are B-1 through B-2C.

I'll haphazardly copy-paste the chunk of the book for your perusal.

MA-1 through MA-5A are clearly missile model numbers, not engine numbers.  ("In the MA-1 model", "In the MA-2 and MA-5 models", "The Atlas MA-3 was equipped",  "In the last Atlas version, the MA-5A".)  The Wikipedia entry on the Atlas further clarifies that those are model numbers for various engine configurations.

[DDE]

12 hours ago, DerekL1963 said:

MA-1 through MA-5A are clearly missile model numbers, not engine numbers.  ("In the MA-1 model", "In the MA-2 and MA-5 models", "The Atlas MA-3 was equipped",  "In the last Atlas version, the MA-5A".)  The Wikipedia entry on the Atlas further clarifies that those are model numbers for various engine configurations.

A fair point. Problem is, Sutton never really distinguishes the name of the missile from the name of the main engine. Indeed, IIRC he calls it standard Rocketdyne practice at some point.

Quote

In this book engines will be identified by the application or flight vehicle and in some cases by the company's designation or by another designation.

Down to the Atlas report, then. As an aside, I don't understand what DoD is trying to accomplish by blocking all queries to .mil addresses from Russia. It's not like VPNs and botnets-for-hire in other countries are a thing, right?

Quote

All the Series D missiles included in the scope of this report employed the Rocketdyne MA-2 propulsion system consisting on one XLR89-NA-3 booster engine package, one XLR105-NA-3 sustainer engine, and two XLR 1101-NA-3 Vernier engines.

All in all, I think OP's looking for Figure 6.1-6. They didn't give the Sustainer any other designation. The numbering of the booster (B) and Vernier (V) engines is clockwise, while the direction of flight changes by 90 degrees between two autopilot models (D-RIG and D-AIG), adding 5 sec to the roll program duration.