Author Topic: Delta IV Q&A  (Read 243194 times)

Offline mmeijeri

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Re: Delta IV Q&A
« Reply #340 on: 11/10/2009 07:14 am »
It was recently mentioned that Delta needs very strict alignment of its cores and solids. What causes the need for extreme precision? What bad things would happen if they were only roughly aligned? I'm trying to understand if the same thing would apply to Microcosm/Beal/Truax style, very strong and stiff pressure-fed rockets.
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Offline Jim

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Re: Delta IV Q&A
« Reply #341 on: 11/10/2009 01:17 pm »
It was recently mentioned that Delta needs very strict alignment of its cores and solids. What causes the need for extreme precision? What bad things would happen if they were only roughly aligned? I'm trying to understand if the same thing would apply to Microcosm/Beal/Truax style, very strong and stiff pressure-fed rockets.

Off centered thrust from a solid would be inefficient and require the core to counter, causing further inefficiencies.

Offline mmeijeri

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Re: Delta IV Q&A
« Reply #342 on: 11/10/2009 01:36 pm »
So how accurate do the alignments have to be? Fractional degrees?
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Offline Antares

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Re: Delta IV Q&A
« Reply #343 on: 11/12/2009 11:42 pm »
Re RL10B-2 nozzles: the supplier is SNECMA, but I'm not familiar with any advance purchase of nozzles.  There are lots of whole RL10s, not just nozzles, sitting around due to low flight rate.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

Offline Propforce

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Re: Delta IV Q&A
« Reply #344 on: 11/16/2009 02:36 pm »
Very good, sir.  That precisely is or has been investigated.  The performance boost is not for Ares V.  Ares V is using the performance boost from the Delta IV Heavy Upgrade.

Well... this will all be OBE soon  ;D

Offline Propforce

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Re: Delta IV Q&A
« Reply #345 on: 11/16/2009 02:57 pm »
Quote
Ronsmytheiii - 23/4/2008  5:43 PM
This may not be as sophisticated as the other questions, but what is a good book as an overview of the Delta IV system and its development? And if any other books of other launchers if know.
Rocketdyne had an internal and PR magazine called Threshold.  There was one called "First Flight Edition" for RS-68 that gave a very good overview of the development of the engine.  I can't find it on Google.  Maybe a request to Canoga to get a soft copy of it.

Doubtful there's a book on this, exactly.  I suggest looking at AIAA papers over the 1997-2004 and more recent time period.


Here's the new link to re-named PWR Engineering where you'll find many excellent technical articles on engine designs

http://www.pwrengineering.com/data.htm

Here's the link to article on RS-68, published in 2002

http://www.pwrengineering.com/dataresources/EvolvedExpendableLaunchVehicleSystem-RS-68MainEngineDevelopment.doc

Offline kevin-rf

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Re: Delta IV Q&A
« Reply #346 on: 11/16/2009 07:21 pm »
Drool,... Thanks Propforce
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It's your med's!

Offline Nick L.

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Re: Delta IV Q&A
« Reply #347 on: 11/27/2009 04:21 am »
Looking at the mission booklet for the upcoming WGS launch, it says that only two of the four GEM-60s have TVC, why not have it on all four?
"Now you may leave here for four days in space, but when you return it's the same old place..."

Offline Skyrocket

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Re: Delta IV Q&A
« Reply #348 on: 11/27/2009 05:40 am »
Looking at the mission booklet for the upcoming WGS launch, it says that only two of the four GEM-60s have TVC, why not have it on all four?

It is simply not necessary.

Offline SpaceCat

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Re: Delta IV Q&A
« Reply #349 on: 12/05/2009 05:06 pm »
In one of the EELV alternative threads, I recall PadRat saying the Delta IV requires its pad to be 'pretty much the most level surface on earth'......
I'm curious why that tolerance is so tight? 

Sure, you want a level pad- but the millisecond the bird lifts, guidance is gimballing the engines, yes?  So is the critical levelling requirement related to GSE/propellant connections.... cryo settling.... or what?

Advance thanks for your answers! 

Offline Jim

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Re: Delta IV Q&A
« Reply #350 on: 12/05/2009 05:38 pm »
In one of the EELV alternative threads, I recall PadRat saying the Delta IV requires its pad to be 'pretty much the most level surface on earth'......
I'm curious why that tolerance is so tight? 

Sure, you want a level pad- but the millisecond the bird lifts, guidance is gimballing the engines, yes?  So is the critical levelling requirement related to GSE/propellant connections.... cryo settling.... or what?

Advance thanks for your answers! 

Not the pad, but the floor in the HIF for stage alignment

Offline JosephB

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Re: Delta IV Q&A
« Reply #351 on: 12/06/2009 02:48 am »
I wonder if any new info on base heating can be gleaned from this latest config with the RS-68 sandwiched between 4 solids?

I've read in other threads that clustering is going to be a major problem? (even without shuttle SRB's)

Beautiful looking launch by the way!

Offline Antares

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Re: Delta IV Q&A
« Reply #352 on: 12/06/2009 05:05 pm »
You mean base heating on a potential NASA HLV?  It's too geometry-dependent to translate to a different configuration.  I'm sure they instrumented the heck out of the Delta IV boat tail on this launch.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

Offline Propforce

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Re: Delta IV Q&A
« Reply #353 on: 12/07/2009 09:32 pm »
I wonder if any new info on base heating can be gleaned from this latest config with the RS-68 sandwiched between 4 solids?

I've read in other threads that clustering is going to be a major problem? (even without shuttle SRB's)

Beautiful looking launch by the way!

You're probably thinking using the RS-68s for Ares V where six RS-68 is packaged in between two 5.5 segment of SRBs.


Offline Jim

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Re: Delta IV Q&A
« Reply #354 on: 04/01/2010 10:12 pm »
Pretty sure that this is a Delta II second stage, can anyone confirm?

not any type of Delta hardware
« Last Edit: 04/01/2010 10:13 pm by Jim »

Offline bobthemonkey

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Re: Delta IV Q&A
« Reply #355 on: 04/01/2010 11:01 pm »
High Bypass Turbofan by the looks of things.

Offline Jim

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Re: Delta IV Q&A
« Reply #356 on: 04/01/2010 11:07 pm »
High Bypass Turbofan by the looks of things.

Bingo

With a composite fan housing.
« Last Edit: 04/01/2010 11:07 pm by Jim »

Offline Rabidpanda

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Re: Delta IV Q&A
« Reply #357 on: 04/07/2010 07:07 am »
Question:

Can the Delta IV heavy take a payload directly to EML 1? Or any langrange point for that matter?  Has this been done before?

Offline mmeijeri

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Re: Delta IV Q&A
« Reply #358 on: 04/07/2010 10:42 am »
GEO is further delta-v wise, so it should be able to take substantial payloads to L1. As I understand it it would need a long duration mission kit to stay alive for long enough to do the insertion burn, unless the payload did that itself, which would not be a strange thing. If you used a quasi-ballistic trajectory that should require only stationkeeping capability.
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Offline JosephB

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Re: Delta IV Q&A
« Reply #359 on: 07/02/2010 07:42 pm »
Hypothetical question if I may, suppose DIVH is selected to launch a ISS & BEO Orion. Is it likely the crossfeed option (from booster to core) would happen?
What kind of extra performance could be expected? (assuming 68A) Thanks!

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