posted 09-03-2013 06:48 AM               

One particular part has a tag on it that states "Removed from 113D." The sales person from Norton Sales thought it might be from an Atlas missile, but wasn't sure.

Of course Atlas 113-D was the Atlas that launched Wally Schirra on his Mercury Sigma 7 mission in October 3, 1962.

I've done some Internet research to see if there is any mention of a valve being replaced on 113-D, but the only reference I could find that mentioned a part replacement was a valve on the Mercury capsule, and I doubt that would have been a Rocketdyne part.

I assume that this Rocketdyne valve was related to the engines or the missile/engine interface, but I haven't found any good photos or documents on the "boat tail" end of the Atlas. Because of the boat tail end is covered with a insulation blanket, good photos of the engine/missile interface are rare. It is possible that this valve was removed at Convair long before the missile was shipped from the factory.

Any help in locating information about this part would be greatly appreciated!

Several photos and part/serial numbers are located at this site. — Mark Trotter

posted 10-26-2013 06:44 PM               

Writing on the tag attached to the valve states...

Removed from 113D
Per R1079-53
GMA- ECP MA2-41

I still assume that "113D" refers to the Atlas D of Wally Schirra's Mercury-Atlas 8 - Sigma 7.

I did find a few documents that suggest the "ECP" stands for "Engineering Change Proposal" and that "MA2" is the booster engine cluster of the Atlas D, otherwise known as XLR89-5. Perhaps "MA2-41" is a specific engine number.

My understanding is that the Atlas D used a single turbo pump to provide fuel and oxidizer to both booster thrust chambers. I believe the sustainer engine had its own turbopump since the booster engines were jettisoned in later in flight. See: XLR89-5.

posted 10-23-2014 05:11 PM               

Some common Rocketdyne F-1-related documents have a list of engine modifications. The table listing these modifications has columns for "Approved ECP No.", "MD No.", and the date of the manual describing engines containing the change. The approved ECP numbers for the F-1 are of the form "F1-57", so it would seem likely that "ECP MA2-41" indicates that it's the 41st ECP for the MA2 engine.

Just a wild guess regarding "per R1079-53," but many Rocketdyne manuals begin with R, have 4 digits, and may optionally have a dash with additional digits. For example, "R-3896-6" is the Rocketdyne manual regarding F-1 Rocket Engine Thermal Insulation Installation and Repair.

Of course, there's no dash between the leading 'R' and the four digits (which might be rationalized away by saying that someone was being a bit informal on a hand-written tag). Harder to rationalize away would be the "-53", when the (presumably more complex) F-1 only had 11 manuals in its series.