Quote from: woods170 on 12/17/2014 08:26 pmThat's a fact. Aerojet and/or Rocketdyne should have gotten off their respective *sses years ago and should have started developing engine(s) to compete with the stuff from Russia.How was that supposed to work? Before the political crisis everyone was perfectly happy, but you think that back then Aerojet or Rocketdyne should have designed a highly complex rocket engine for ULA or Orbital, just in case something would go wrong and someone would need an engine? I think no one can expect to develop an engine like an RD180 or RD181 on own money just in case it is needed.
That's a fact. Aerojet and/or Rocketdyne should have gotten off their respective *sses years ago and should have started developing engine(s) to compete with the stuff from Russia.
Quote from: Remes on 12/17/2014 10:45 pmQuote from: woods170 on 12/17/2014 08:26 pmThat's a fact. Aerojet and/or Rocketdyne should have gotten off their respective *sses years ago and should have started developing engine(s) to compete with the stuff from Russia.How was that supposed to work? Before the political crisis everyone was perfectly happy, but you think that back then Aerojet or Rocketdyne should have designed a highly complex rocket engine for ULA or Orbital, just in case something would go wrong and someone would need an engine? I think no one can expect to develop an engine like an RD180 or RD181 on own money just in case it is needed.No, not everyone was perfectly happy. Many in Congress, and probably in the Pentagon too, have been unhappy for years about sending national security dollars to Russia but were unable to force ULA to develop an alternative engine.
Huh? pure nonsense please go read the history at the end of the Soviet Union. It was the US Government that promoted the purchase of Russian engines. It's all there in black and white.
Quote from: Prober on 12/18/2014 01:08 amHuh? pure nonsense please go read the history at the end of the Soviet Union. It was the US Government that promoted the purchase of Russian engines. It's all there in black and white.Please refrain from rendering judgement on other member's opinions.The US government isn't a single opinion. There are many voices. Some have felt strongly about using Russian engines (one way or the other) and some have not. This is an opportunity for the nahs to get their ways.
Quote from: edkyle99 on 12/17/2014 07:19 pmA killer for Aerojet-Rocketdyne. Some of those funds were originally headed for California. Now they're Russia-bound. I shed no tears, however, because it is the U.S. company's own fault. - Ed KyleThat's a fact. Aerojet and/or Rocketdyne should have gotten off their respective *sses years ago and should have started developing engine(s) to compete with the stuff from Russia. The fact that they didn't is now taking significant bites out of their business.
A killer for Aerojet-Rocketdyne. Some of those funds were originally headed for California. Now they're Russia-bound. I shed no tears, however, because it is the U.S. company's own fault. - Ed Kyle
NPO Energomash did that (both RD-193 and RD-181)
Blue Origin
XCOR
Or did they pushed to have have the RD-180 built locally? Nope, they were happy to leave manufacturing to the Russians and have a "free" 15% through RD AMROSS.
Quote from: woods170 on 12/17/2014 08:26 pmQuote from: edkyle99 on 12/17/2014 07:19 pmA killer for Aerojet-Rocketdyne. Some of those funds were originally headed for California. Now they're Russia-bound. I shed no tears, however, because it is the U.S. company's own fault. - Ed KyleThat's a fact. Aerojet and/or Rocketdyne should have gotten off their respective *sses years ago and should have started developing engine(s) to compete with the stuff from Russia. The fact that they didn't is now taking significant bites out of their business.This.I'm kind of appalled at Aerojet/Rocketdyne's unwillingness to compete. Even ULA is basically doing everything they can to get engines from someone else. Doesn't Aerojet/Rocketdyne have ANY will to survive??! It's like they won't lift a finger of real, hardcore engineering work without someone else totally footing the bill. I see some news bites of 3d printing some rocket thruster (old news, others have done it years ago, now), but nothing real.And it's a shame! They make great engines! But I doubt they'll exist in 10 years without a huge change in strategy.
So from what I've read, they will operate the engine in a reduced throttle mode equivalent to the AJ-26 output on the existing Antares tanks until they can redesign the thrust structure to handle the extra thrust. Any ideas on how that will impact the performance, isp? Won't this also limit them increasing the amount of cargo Cygnus can carry to what the Antares could do with the AJ-26 until they have a new thrust structure? I assume there is probably some extra margin in the existing structure for a modest increase in output but if they have to keep it close to what the AJ-26 could do until its redesigned I'm curious what the impact is on performance.
Not necessarily - remember it will get more thrust AND better Isp. Higher TWR will reduce gravity losses too.
I'm kind of appalled at Aerojet/Rocketdyne's unwillingness to compete. Even ULA is basically doing everything they can to get engines from someone else. Doesn't Aerojet/Rocketdyne have ANY will to survive??! It's like they won't lift a finger of real, hardcore engineering work without someone else totally footing the bill. I see some news bites of 3d printing some rocket thruster (old news, others have done it years ago, now), but nothing real.And it's a shame! They make great engines! But I doubt they'll exist in 10 years without a huge change in strategy.
Quote from: asmi on 12/18/2014 02:01 pmNot necessarily - remember it will get more thrust AND better Isp. Higher TWR will reduce gravity losses too.True, but these are marginal improvements. An extra 50 tonnes of propellant could result in a substantial performance improvement. - Ed Kyle
Isn't Antares-130 T/W close to 1.1. Just putting a bit more thrust will help things significantly.
Quote from: Robotbeat on 12/18/2014 04:15 amQuote from: woods170 on 12/17/2014 08:26 pmQuote from: edkyle99 on 12/17/2014 07:19 pmA killer for Aerojet-Rocketdyne. Some of those funds were originally headed for California. Now they're Russia-bound. I shed no tears, however, because it is the U.S. company's own fault. - Ed KyleThat's a fact. Aerojet and/or Rocketdyne should have gotten off their respective *sses years ago and should have started developing engine(s) to compete with the stuff from Russia. The fact that they didn't is now taking significant bites out of their business.This.I'm kind of appalled at Aerojet/Rocketdyne's unwillingness to compete. Even ULA is basically doing everything they can to get engines from someone else. Doesn't Aerojet/Rocketdyne have ANY will to survive??! It's like they won't lift a finger of real, hardcore engineering work without someone else totally footing the bill. I see some news bites of 3d printing some rocket thruster (old news, others have done it years ago, now), but nothing real.And it's a shame! They make great engines! But I doubt they'll exist in 10 years without a huge change in strategy.Not really AR fault why do you think Rocketdyne was sold off? Low launch rates, and the company lives or dies by Government programs. Even the mighty SpaceX is going corporate. Read some of the employee reports if you don't wish to believe it. But the fact is SpaceX needs the government money too.I've been pushing for sometime that AR made a major mistake when they did the merger. They should have made two divisions within the company and cleaned the government stuff away from a clean "commercial" type company. The company still needs this to survive IMHO.