tater Posted April 14, 2018 Share Posted April 14, 2018 Quote Link to comment Share on other sites More sharing options...
_Augustus_ Posted April 14, 2018 Share Posted April 14, 2018 23 minutes ago, tater said: Tory must be cursing right now that they ever agreed to buy BE-4s. Quote Link to comment Share on other sites More sharing options...
Streetwind Posted April 14, 2018 Share Posted April 14, 2018 Strictly speaking they have not yet agreed to buy BE-4's. They've merely stated that it is the forerunner right now, with Aerojet Rocketdyne being more than a year behind in development progress. Quote Link to comment Share on other sites More sharing options...
_Augustus_ Posted April 14, 2018 Share Posted April 14, 2018 35 minutes ago, Streetwind said: Strictly speaking they have not yet agreed to buy BE-4's. They've merely stated that it is the forerunner right now, with Aerojet Rocketdyne being more than a year behind in development progress. AR1 would require a complete redesign from what they currently have. They've already selected the engine (it's probably BE-4). ULA is pretty much locked in now. Quote Link to comment Share on other sites More sharing options...
Streetwind Posted April 15, 2018 Share Posted April 15, 2018 Source for that? Last I heard, Vulcan was still in parallel development for both engine options. Development gets signed off quarter by quarter, so perhaps they decided to cancel the kerolox varaint recently... but that would probably have made SpaceNews.com, and I read that religiously. Quote Link to comment Share on other sites More sharing options...
_Augustus_ Posted April 15, 2018 Share Posted April 15, 2018 4 hours ago, Streetwind said: Source for that? Last I heard, Vulcan was still in parallel development for both engine options. Development gets signed off quarter by quarter, so perhaps they decided to cancel the kerolox varaint recently... but that would probably have made SpaceNews.com, and I read that religiously. They have already selected the engine, just not announced yet. Almost definitely BE-4. Quote Link to comment Share on other sites More sharing options...
MaverickSawyer Posted April 16, 2018 Share Posted April 16, 2018 Agreed. The information I've been seeing points to the tankage for Vulcan being configured for metholox, and therefor the BE-4. Quote Link to comment Share on other sites More sharing options...
Racescort666 Posted April 16, 2018 Share Posted April 16, 2018 Metholox in a booster/first stage makes a ton of sense. You get high density TWR but ~50s better sea level ISP. Engine TWR seems to be less important in upper stages but in boosters you have a minimum vehicle TWR that you’re trying to maintain so I suspect that it has a pretty direct correlation to how big the rocket needs to be. Plus the fuel is relatively cheap. When you start talking about booster reuse, supposedly it doesn’t coke up as bad but I have nothing to back this up other than hearsay. Quote Link to comment Share on other sites More sharing options...
tater Posted April 16, 2018 Share Posted April 16, 2018 Both are right. ULA hasn't officially said anything, but they clearly seem pointed in the methlox direction. Quote Link to comment Share on other sites More sharing options...
tater Posted April 16, 2018 Share Posted April 16, 2018 Quote Link to comment Share on other sites More sharing options...
Scotius Posted April 16, 2018 Share Posted April 16, 2018 Dang, couldn't they include even one medium build human for size-comparision purposes? Or a banana at least? Quote Link to comment Share on other sites More sharing options...
tater Posted April 16, 2018 Share Posted April 16, 2018 1 hour ago, Scotius said: Dang, couldn't they include even one medium build human for size-comparision purposes? Or a banana at least? The banco on the left is sitting height I bet. Call it knee high. Quote Link to comment Share on other sites More sharing options...
Racescort666 Posted April 16, 2018 Share Posted April 16, 2018 3 hours ago, tater said: If only someone had a decent picture of the BE-3U, I could estimate the size and weight. As for this engine, scaling off of the work lights or casters would probably be a safe bet. I can probably get a drawing of those casters from an industrial supply company and go from there. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted April 16, 2018 Share Posted April 16, 2018 11 minutes ago, Racescort666 said: If only someone had a decent picture of the BE-3U, I could estimate the size and weight. As for this engine, scaling off of the work lights or casters would probably be a safe bet. I can probably get a drawing of those casters from an industrial supply company and go from there. http://www.b14643.de/Spacerockets_2/United_States_1/B.O._New-Glenn/Propulsion/engines.htm There's the BE-3U. I was looking for those work lights too. Then I realized there is someone standing right behind it: Quote Link to comment Share on other sites More sharing options...
Racescort666 Posted April 16, 2018 Share Posted April 16, 2018 @sevenperforce good eye. I'll have to update my BE-3 vs BE-4 spreadsheet with this new information although their numbers for the BE-3U vacuum ISP are a bit suspect. They're estimating 406 s for ISP, this seems very low to me; the RS-68A has got a vacuum ISP of 412 for a atmospheric-optimized gas generator engine. Maybe I need to go and read some more of my rocket engine book but I would have thought the BE-3U to be in the 420-440 second range and more in line with the J-2's performance. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted April 16, 2018 Share Posted April 16, 2018 18 minutes ago, Racescort666 said: @sevenperforce good eye. I'll have to update my BE-3 vs BE-4 spreadsheet with this new information although their numbers for the BE-3U vacuum ISP are a bit suspect. They're estimating 406 s for ISP, this seems very low to me; the RS-68A has got a vacuum ISP of 412 for a atmospheric-optimized gas generator engine. Maybe I need to go and read some more of my rocket engine book but I would have thought the BE-3U to be in the 420-440 second range and more in line with the J-2's performance. I would definitely expect a higher vacuum Isp. I know the BE-3 has very deep throttle ability, which means its chamber pressure needs to be quite high (to inhibit flow separation), which probably means a slightly greater combustion tap-off (to run the turbopump) than would be necessary for a smaller throttle range. But 406 has got to be way, way too low. Too low, even, for the BE-3 vacuum Isp without the bigger nozzle. Quote Link to comment Share on other sites More sharing options...
MaverickSawyer Posted April 16, 2018 Share Posted April 16, 2018 For scale, the BE-4 engine bell is 7 feet in diameter at the mouth. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted April 17, 2018 Share Posted April 17, 2018 15 hours ago, MaverickSawyer said: For scale, the BE-4 engine bell is 7 feet in diameter at the mouth. Good call. Quote Link to comment Share on other sites More sharing options...
tater Posted April 18, 2018 Share Posted April 18, 2018 Quote Link to comment Share on other sites More sharing options...
tater Posted April 18, 2018 Share Posted April 18, 2018 I know most here are not BO fanbois, but BO is gonna hit the market like a freight train. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted April 18, 2018 Share Posted April 18, 2018 4 minutes ago, tater said: I know most here are not BO fanbois, but BO is gonna hit the market like a freight train. New Glenn will hit the market like a freight train. I'm a fan of whatever lowers the cost of access to space. Quote Link to comment Share on other sites More sharing options...
tater Posted April 18, 2018 Share Posted April 18, 2018 2 minutes ago, sevenperforce said: New Glenn will hit the market like a freight train. I'm a fan of whatever lowers the cost of access to space. As am I, but They're doing the same math... interesting times. Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted April 18, 2018 Share Posted April 18, 2018 52 minutes ago, tater said: I know most here are not BO fanbois, but BO is gonna hit the market like a freight train. Competition is good, and sorely needed in the industry as it will benefit everyone. But they’ll never do anything as cool as Starman go on and prove me wrong, Bezos. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted April 18, 2018 Share Posted April 18, 2018 21 minutes ago, CatastrophicFailure said: Competition is good, and sorely needed in the industry as it will benefit everyone. But they’ll never do anything as cool as Starman go on and prove me wrong, Bezos. I'm not quite sure what would be cooler than Starman. Sending a pallet with a billion dollars into space is something Bezos can afford to do that Musk can't. Though that's not exactly cool, just flashy and obnoxious. New Glenn will likely be able to go interstellar with a small enough payload. That would be a cool inaugural flight. Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted April 18, 2018 Share Posted April 18, 2018 8 minutes ago, sevenperforce said: New Glenn will likely be able to go interstellar with a small enough payload. That would be a cool inaugural flight. Not pragmatic enough, wouldn’t demonstrate the lift capacity. I’m expecting a nice, boring, practical hunk of concrete... which we’ll be told about a week after it happens. Tho I wonder if they might start out with NG “grasshopper” flights? The factory’s done, so we should start seeing some test hardware soon. Quote Link to comment Share on other sites More sharing options...
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