Jim - 2/11/2006 8:02 AMHow many people know that the reason why the RP-1 on Delta II is loaded late in the countdown?It is because it is heated to the high 80's F to increase first stage performance
kevin-rf -2/11/2006 8:47 AM Okay Jim, I'm gonna feed the troll a little... I can not find the exhaust temp of the RS-27, so I'm gonna guess 3000 Deg C and your favorite source list the Vac ISP at 303. So if 3000 (Yes I sould convert from C to Kelvin, but I don't have a real exhaust temp) = 303 ISP Boosting the Fuel Temp by ~30 Deg Kelvin would result in (3000 + 30) * 303 ISP / (3000) = 306 ISP So you gain a 3 in your vehicle ISP? How close am I?
Propforce - 2/11/2006 1:13 PMJust talked to my Delta II propellant guru ....You were right, the RP is heated to increase the overall vehicle performance. Even though this reduces propellant density thereby reducing the total RP-1 loading, it still provides an overall vehicle delta-vee advantage. This practice is opposite of what Atlas II and Sealaunch were doing, from what I understand. Both were chilling their propellants to maximize mass loading.Now why the difference approach, that's a good question...
Propforce - 2/11/2006 4:02 PMIT was Atlas II and not Atlas V
Jim - 2/11/2006 1:02 PMAtlas V loads the RP-1 once for WDR and leaves it in until launch. So it is subjected to the ambient temps and therefore not chilled.Zenit is different and is detanked after every attempt.
bigdog - 16/3/2007 7:00 AMQuoteJim - 2/11/2006 1:02 PMAtlas V loads the RP-1 once for WDR and leaves it in until launch. So it is subjected to the ambient temps and therefore not chilled.Zenit is different and is detanked after every attempt.Is that just if the WDR is close to launch? I'm told by someone who supported the STP launch that it was loaded the day before after they rolled out. Also wouldn't that make things more hazardous having it loaded during the transport and during the down time at the VIF?
publiusr - 30/3/2007 3:31 PMJim, if you were given supervision over Zenit's fuel loading, would you heats its RP, and or change any of the fuel handling?