Merlin-1

[Salo]

На каком двигателе?

[Uriy]

На каком двигателе?

 5Д25

[Salo]

Спасибо! :wink:

[Salo]

Небольшая дискуссия о Мерлине  на NSF:
http://forum.nasaspaceflight.com/index.php?topic=24179.msg733135#msg733135

One thing I did notice was this: Sea Level Thrust : 556 kN (125,000 lbf)

That seems out of date already.  Last I heard it was up to 140,000 lbf, up from 135,000 lbf as of early January.  
Doesn't SpaceX usually quote the Sea Level Thrust, not the Vacuum Thrust?

And the fact first stage Merlin vaccum Isp is reported under 2nd stage MVac Isp doesn't set off an alarm?

This was done by their PR department - if they have one. I still hold COTS C1 press kit as more definitive with respect to performance numbers for Block 1.

Alarms? That's a bit strong, but you have found another inconsistency.
However, Block 1 is now "old hat", obsolete.

Falcon 9 Block 1 is not obsolete because it is still flying.  The Falcon 9 now at SLC 40, for example, is a Block 1.  

The numbers provided in the document appear to be from the User's Guide currently posted on the SpaceX web site (except that the Merlin Vacuum ISP has a typo - it should be 340 sec rather than 304 sec).  The 125Klbf thrust was the original sea-level thrust listed in the Guide for the Block 2 Falcon 9 that has not flown, and may or may not ever fly depending on what the company does with Merlin 1D.

 - Ed Kyle

[Петр Зайцев]

Небольшая дискуссия о Мерлине  на NSF:
http://forum.nasaspaceflight.com/index.php?topic=24179.msg733135#msg733135

Falcon 9 Block 1 is not obsolete because it is still flying.  The Falcon 9 now at SLC 40, for example, is a Block 1.  

The numbers provided in the document appear to be from the User's Guide currently posted on the SpaceX web site (except that the Merlin Vacuum ISP has a typo - it should be 340 sec rather than 304 sec).  The 125Klbf thrust was the original sea-level thrust listed in the Guide for the Block 2 Falcon 9 that has not flown, and may or may not ever fly depending on what the company does with Merlin 1D.

Вот за это мы и любим Эда, он знает о чем говорит. Надо только иметь в виду, что когда он начинает рассуждать про "американскую индустриальную базу", то тут же начинается ангажированность и борьба за сытный попил для его корешей из Пратта.

[Salo]

http://forum.nasaspaceflight.com/index.php?topic=25597.msg759905#msg759905

Elon Musk:
"Our rough ball-park estimate is something on the order of 20 launches a year, of which roughly half are Falcon Heavy and roughly half are Falcon 9, and of those roughly 60%-70% going out of Cape Canaveral."

Comments above starting around 15:40.

http://forum.nasaspaceflight.com/index.php?topic=25597.msg760192#msg760192

http://forum.nasaspaceflight.com/index.php?topic=25597.msg759970#msg759970

I get the impression from their launch manifest that 2013 is the first year of standard operations with the Falcon 9, and everything prior to that is preparatory work.

Next year (2012) they have manifested 3 CRS flights (4 if you include catchup for 2011 if that doesn't happen then) plus potentially a couple of commercials being ORBCOM and MDA Corp.  Don't know where those are at but anyway the CRS flights will definitely be operational flights for both F9 and Dragon Cargo and by definition, that means SpaceX will be in ongoing commercial mode.  Doesn't matter that the flights are for NASA.  There may be more oversight than for other non-gov't flights but the essentials will be the same.
Crunch time for SpaceX.  Will they be able to manifest 3 - 5 flights per year as promised?  

SpaceX has stated that the 7th Falcon 9 will use the Merlin 1D engine. That will likely be when they introduce the longer tanks with a strengthened structure.  That is supposedly two flights before the debut of the Falcon Heavy and includes at least one flight of the 5 meter fairing.  At that point, they will have the stable of rockets they have promised.

FWIW, and admittedly it's not much, my opinion is that they will be in "standard operations" when one can order a rocket that has flown, as opposed to a planned redesign.  Secondarily it will be when burning down the manifest no longer requires a step increse in their flight rate.

Exactly.

According to Max Vozoff, the Merlin 1d has a dramatically lower parts count:
http://thespaceshow.wordpress.com/2011/03/05/max-vozoff-friday-3-4-11/
(starting around 57:30 into the interview).

Also, IIRC, Elon said their assembly line should be capable of producing up to 800 Merlin 1d engines per year.

In other words, the Merlin 1d is designed for mass production.

[Петр Зайцев]

http://www.hobbyspace.com/nucleus/index.php?itemid=31499
Кларк цитирует "Aviation Leak" про Мерлин-1Д. Получается где-то 70-тонник при 310 сек. на 96 атм. в камере. И еще, Мюллер сказал, что опытный образец уже отправили в Техас, т.е. он существует в природе.

[Salo]

http://www.hobbyspace.com/nucleus/index.php?itemid=31499

SpaceX Merlin 1D[/size]

AvWeek reports on the SpaceX presentations at the AIAA propulsion conference last week (see post here): SpaceX Unveils Plans To Be World's Top Rocket Maker - Aviation Week & Space Technology - Aug.8.11 (subscription required) they include some information about the new Merlin engine upgrade:

    Revealing several new details of the 1D, Tom Mueller, propulsion engineering vice president, says the engine is designed to produce 155,000 lb. vacuum thrust and have a chamber pressure at "the sweet spot" of roughly 1,410 psia. "We've also increased the nozzle expansion ratio to 16 [compared with 14.5 on the Merlin 1C]," says Mueller, who adds that the initial engine "is doing better than we hoped." The engine is designed for an Isp (specific impulse) of 310 sec. and has a thrust-to-weight ratio of 160:1. "We took structure off the engine to make it lighter. The engine we shipped [for test] to Texas was a development engine and hopefully the production engines will be even better," he says.

Mueller also said that they have used lessons from the previous versions to go with a simpler design for the 1D and a longer fatigue life.

The 1D will allow for throttling between 70-100%. Currently they shut off two of the nine engines on the first stage during ascent. With the 1D they will instead be able to throttle all of the engines.

There will be a vacuum version of the 1D for the Falcon Heavy second stage.

Posted 08/06/11 | 14:07:06 by TopSpacer [/size]

[Salo]

Т.е. ни одного прожига пока ещё не было? Ну вот и поглядим.
А FH планируют пускать уже через год-полтора.

[Петр Зайцев]

Год уйдет на доработку СК. Там только на этой неделе начали разбирать старые сооружения от Титана. Ну и потом всякие испытания. Февраль 2013 если повезет, не раньше.

[Salo]

Год на отработку двигателя открытой схемы с предельными параметрами это супер рекордный срок.

Давление в КС на 20% выше чем у РД-111 при сравнимом УИ. Земной видимо на 10 секунд выше за счёт меньшей степени расширения сопла (16 против 18 у РД-111).

Кстати у РД-111 удельная тяга  112, против 160 у 1D.

А у НК-33 только 123. :roll:

[hecata]

310 секунд при 160 килограммах тяги на килограмм веса, это заявка на рекорд весовой эффективности среди керосиновых двигателей. Получается в 2 раза легче РД-107А, при чуть меньшем вакуумном УИ (и очевидно большем земном, давление на 50% выше).

[hecata]

Год на отработку двигателя открытой схемы с предельными параметрами это супер рекордный срок.

Давление в КС на 20% выше чем у РД-111 при сравнимом УИ. Земной видимо на 10 секунд выше за счёт меньшей степени расширения сопла (16 против 18 у РД-111).

Кстати у РД-111 удельная тяга  112, против 160 у 1D.

А у НК-33 только 123. :roll:

4-х камерный против 1-камерного + более современные материалы и проектирование, вполне возможно.

Вопрос в давлении, не многовато ли.

[Salo]

Тяга-то в два раза ниже. :roll:

[Salo]

http://forum.nasaspaceflight.com/index.php?topic=25597.msg789767#msg789767

[Salo]

http://forum.nasaspaceflight.com/index.php?topic=25597.msg789864#msg789864

The SL ISP for 1D was modeled using the given values on Aximer using the observed 1C values to determine some of the unknown values so a change in the chamber pressure can then give a reasonable SL calculated value. The result was that it showed that by changing to the higher pressure the 1D should get about or better than 273s SL ISP.  Aximer has limitations because it is idealistic but by adjusting until it gives the observed value in one case then changing only one input value such as chamber pressure a reasonably accurate new value like ISP can be calculated.

The T/W value was changed because the engine weight 655kg divided into the VAC thrust gives 75 not 96.[/size]

edit - P.S. The VAC thrust of 1D could be as high as 160klbf giving an engine weight of 440 to 455kg. Thats a stage dry weight reduction of 1800 to 1935kg.

http://forum.nasaspaceflight.com/index.php?topic=25597.msg789979#msg789979

Just trying to get the numbers straight.  

The Merlin 1C has a T/W ratio of 92 and a SL thrust of 95,000 lbs (source: http://www.spacex.com/press.php?page=33 ).

The Merlin 1C weighs: 95,000 lbs / 92 = 1032 lbs (468kg)

The Merlin 1D has a T/W ratio of 160 and a SL thrust of 140,000 lbs (source: http://hobbyspace.com/nucleus/?itemid=31499 ).

The Merlin 1D weighs: 140,000 lbs / 160 = 875 lbs (397kg)

So a reduction of 71 kg. Right?
Regards,
arnezami

[Salo]

Т.е. при росте тяги в 140000 / 95000= 1,47 раза и давления в КС в 1420 / 982 = 1,45 раза масса двигателя уменьшилась 397 / 468 = 0,848 на 15%. :roll:

[Salo]

С некоторыми корректировками:

[hecata]

Т.е. при росте тяги в 140000 / 95000= 1,47 раза и давления в КС в 1420 / 982 = 1,45 раза масса двигателя уменьшилась 397 / 468 = 0,848 на 15%. :roll:

Сопло будет длиннее,  добавится арматура для дросселирования. ТНА, как я понимаю в ~2 раза мощнее.

Возникает легкий скепсис.

[hecata]

Кстати по последней табличке Мерлин будет весить 439 кг, а не 397.