Author Topic: SCE-200 semi-cryo engine info  (Read 69918 times)

Offline vineethgk

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Re: SCE-200 semi-cryo engine info
« Reply #100 on: 01/11/2018 04:17 AM »
Seems like India will have a fine engine for an RLV. Just cluster seven SC-200s like Blue Origin is doing with their BE-4 for the first stage.
They have been toying with a design having a cluster of 5 engines for the first stage. Not sure if they can use the central engine for propulsive recovery in that configuration though. I'm guessing the engine would need to be capable of burning at a much lower than nominal thrust for that to work out.

Offline sanman

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Re: SCE-200 semi-cryo engine info
« Reply #101 on: 01/17/2018 02:54 PM »
Seems like India will have a fine engine for an RLV. Just cluster seven SC-200s like Blue Origin is doing with their BE-4 for the first stage.
They have been toying with a design having a cluster of 5 engines for the first stage. Not sure if they can use the central engine for propulsive recovery in that configuration though. I'm guessing the engine would need to be capable of burning at a much lower than nominal thrust for that to work out.

Maybe hoverslam can compensate for throttleability?

Offline TrevorMonty

Re: SCE-200 semi-cryo engine info
« Reply #102 on: 01/17/2018 05:40 PM »
They may go VTOHL. Already proved they can do HL. HL doesn't scale like VL but it is easier to get right first time and that is important R&D cost saving.

If VTOHL booster can deliver 4t GTO or 10t LEO, that is most of commercial market. For bigger LV use two fly back boosters with expendable core.

Offline GreenShrike

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Re: SCE-200 semi-cryo engine info
« Reply #103 on: 01/17/2018 06:18 PM »
Seems like India will have a fine engine for an RLV. Just cluster seven SC-200s like Blue Origin is doing with their BE-4 for the first stage.
They have been toying with a design having a cluster of 5 engines for the first stage. Not sure if they can use the central engine for propulsive recovery in that configuration though. I'm guessing the engine would need to be capable of burning at a much lower than nominal thrust for that to work out.

Maybe hoverslam can compensate for throttleability?


Well, F9 can do a 3-engine landing burn, though the 1-3-1 sequence probably averages closer to the overall effect of a 2-engine burn. 2 of a 9 engine cluster is 22% thrust versus the 20% of a 1/5, so the answer is possibly yes, though it'd be a toasty, short duration, high-g burn, with little margin and high risk.

If throttleability is an issue, then a 7-engine cluster is likely safer.

Some very rough math shows a 5 x SCE-200 + 2 x CE-20 can do ~30-33t to LEO while 7 x SCE-200 + 2-3 x CE-20 can do 40-45t. With a 33-50% penalty for first stage recovery, you're looking at a ~15-22t or ~20-30t semi-reusable launcher. If CE-20s aren't too expensive, then 3 on the 7-engine booster would push its second stage comfortably above Centaur-class T/W levels, and at 66% remaining thrust, give the stage a fighting chance at completing the mission in the event of a single-engine failure.

With the flight cost differences between the two being only additional fuel, stretched tanks on the 7-engine booster's S2, refurb on two more booster engines and possibly an extra CE-20, I can see why Steven suggested going with (and Blue actually did chose) the 7-engine booster.
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Offline john smith 19

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Re: SCE-200 semi-cryo engine info
« Reply #104 on: 01/17/2018 11:51 PM »
Current version in development is designed to be expendable with follow-on version designed to support reuse.

Actually SCE-200 is being developed with reusability in mind. Each engine can be reused up to 15 times.

I know the semi-cryo engine intended for use in the planned TSTO (Two-Stage-To-Orbit) vehicle is supposed to be reusable as  you've said, however it's not clear to me whether that engine is the same as the SCE-200, which is meant for replacing the GSLV-Mk3's L110 stage (UDMH/N2O4).

Logically, it might be practical for ISRO to first get SCE-200 non-reusably flying on GSLV-Mk3, which is an expendable launch vehicle, even while it works to achieve reusability on its semi-cryo engine meant for TSTO.

All liquid fuel rocket engines are reusable to a certain extent. The CE-20 that was recently flown on MK-3 was fired 2-3 times before it was flight tested.
There are issues if you choose to do thrust chamber or nozzle cooling with ablative linings, as used on the Merlin 1a, RS68 the Lance missile engines, despite all being liquid propellants.
Seems like India will have a fine engine for an RLV. Just cluster seven SC-200s like Blue Origin is doing with their BE-4 for the first stage.
They have been toying with a design having a cluster of 5 engines for the first stage. Not sure if they can use the central engine for propulsive recovery in that configuration though. I'm guessing the engine would need to be capable of burning at a much lower than nominal thrust for that to work out.
Actually the real achievement of this engine has happened before it has reached a test stand.

ISRO have managed to transfer manufacturing techniques to India and make the engine in India, something which the US failed to do with the RD180, despite having 16 years to do so.  :(

Even if the engine fails to hit it's Isp and thrust targets (I don't expect it will)  that alone is a major achievement for the Indian rocket engineering community.  :)

The spec page for the 810 (from which SCE-200 is descended)
http://www.yuzhnoye.com/en/technique/rocket-engines/marching/rd-810/
Suggests it's roughly a ORSC cycle with Merlin 1d level thrust. Not just SC, Oxygen rich SC.

It might be interesting to compare the development budget of the SC-200 with AJR AR-1.

It's an academic question now but I wonder, if SCE-200 has started earlier would India be deemed a viable supplier of engines for the booster stage of Vulcan? I guess we'll never know.
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Offline TrevorMonty

Re: SCE-200 semi-cryo engine info
« Reply #105 on: 01/18/2018 01:58 AM »





Some very rough math shows a 5 x SCE-200 + 2 x CE-20 can do ~30-33t to LEO while 7 x SCE-200 + 2-3 x CE-20 can do 40-45t. With a 33-50% penalty for first stage recovery, you're looking at a ~15-22t or ~20-30t semi-reusable launcher. If CE-20s aren't too expensive, then 3 on the 7-engine booster would push its second stage comfortably above Centaur-class T/W levels, and at 66% remaining thrust, give the stage a fighting chance at completing the mission in the event of a single-engine failure.


Are you sure of your maths, SCE200 is about same as Merlin and F9 is about 20t to LEO.

Offline sanman

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Re: SCE-200 semi-cryo engine info
« Reply #106 on: 01/18/2018 02:58 AM »
They may go VTOHL. Already proved they can do HL. HL doesn't scale like VL but it is easier to get right first time and that is important R&D cost saving.

If VTOHL booster can deliver 4t GTO or 10t LEO, that is most of commercial market. For bigger LV use two fly back boosters with expendable core.

Yeah, the TSTO design which has long been planned as India's first RLV, is supposed to be VTHL - but I don't see how deep throttleability becomes a major requirement for that.
« Last Edit: 01/18/2018 11:30 AM by sanman »

Offline K210

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Re: SCE-200 semi-cryo engine info
« Reply #107 on: 01/18/2018 09:23 AM »
Updated specs of SCE-200 engine: http://www.russianspaceweb.com/rd810.html

In short:

New SL Thrust: 194 tons

New Vacuum thrust: 211 tons

New SL ISP: 303 seconds

New vacuum ISP: 330 seconds

Offline GreenShrike

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Re: SCE-200 semi-cryo engine info
« Reply #108 on: 01/19/2018 12:02 AM »
Are you sure of your maths, SCE200 is about same as Merlin and F9 is about 20t to LEO.

Yup. As K210 indicated, if you look it up, you'll actually see that Merlin is 900kN, while SCE-200 is ~2MN. As such, the SCE-200 is a bit over twice the size of the Merlin 1D, and most of the size of the ~2.4MN BE-4.

Now add the fact that it's staged combustion and thus gives a decent ISP increase over Merlin's GG cycle, and you have a rather nice engine. That is, assuming it turns out to be reliable -- which I'm hopeful for, as russianspaceweb describes it as "an equivalent of the Russian RD-191 engine, but using a more conservative engineering approach." A conservative approach seems quite reasonable for India's first crack at producing a high performance kerolox engine.


Given the performance, the math also intuitively works out since a bit over twice the thrust per engine over Merlin means a 7 x SCE-200 should, once factoring in needing less booster prop due to the higher ISP, as well as using a high energy upper stage, do about twice what an F9 can do.


And then India can steal from ULA's ACES playbook and start flying hydrolox tankers on top of 7 x SCE-200 boosters to refuel already orbited CE-20 upper stages, except ISRO will have a cheaply reusable booster, and ULA will be flying expendable Vulcans -- but I guess I'm straying off topic... ;-)
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Offline TrevorMonty

Re: SCE-200 semi-cryo engine info
« Reply #109 on: 01/19/2018 12:04 PM »
I was thinking 200klbs not 200t thats where I went wrong.