Thrust Augmented Nozzle (TAN) (Q&A)

Thrust Augmented Nozzle (TAN) (Q&A) by aero on 22 Jun, 2012 22:12
There is a thread in Advanced Concepts on this topic, but the latest post was 4 years ago. Can anyone say if any progress has been made on this concept? If so, what can you say? The most recent published work I find anounced the concept and test results 7 years ago.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA454615

If there has been no progress, then what is the problem? Is the concept invalid, or does the IP holder want to bury the concept for their own reasons?
#1 by jongoff on 22 Jun, 2012 22:54
Quote from: aero on 22 Jun, 2012 22:12
There is a thread in Advanced Concepts on this topic, but the latest post was 4 years ago. Can anyone say if any progress has been made on this concept? If so, what can you say? The most recent published work I find anounced the concept and test results 7 years ago.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA454615

If there has been no progress, then what is the problem? Is the concept invalid, or does the IP holder want to bury the concept for their own reasons?

Can't say I know it's current status, though I don't think much has ended up happening with it over the last several years. I think the problem is more that to take it beyond the analysis, and small-scale hot-fire tests they've done to-date, they need to be tied in with a bigger program. I know they pitched their idea to SpaceX as a Merlin upgrade and to NASA as an upgrade for the RS-68 or SSME. But SpaceX had enough on its plate that it just needed to get Merlin working, and the congressional direction in the NASA Authorization Act of 2010 ended up being less focused on making sure we actually mature and infuse advanced technologies that could improve our capabilities, and was focused more on trying to retain legacy jobs and legacy systems, and incorporate them into a big monster rocket.

~Jon
#2 by aero on 22 Jun, 2012 23:43
So you think it's nothing more than the TRL-5 funding gap?

Also, regarding SpaceX. Would the benefits of TAN be as significant when applied to SpaceX's RP-1/LOX engines? Applied to the SSME, the upper limit for Isp is over 450 seconds, but for the Merlin engines, the top Isp is in the low to mid 300 second range. Of course TAN would burn additional fuel generating more thrust, but 400 seconds, (estimated for TAN on the SSME) would be out of reach for an RP-1/LOX burning Merlin, seems to me.

Another off the wall question, Could an SSTO burning RP-1/LOX even reach orbit given the available Isp? I'll look at the rocket equation and see. (My answer is, "Probably not.")
#3 by Archibald on 28 May, 2013 09:15
In another thread a while back someone had this interesting question

Quote
The RD-701 engine (brought up by another poster) is interesting - Was that just a fuel switching engine, or a TAN engine before the TAN term was coined?

I think the difference between the two is just - where do you inject the kerosene ?
On the RD-701 it was injected into the combustion chamber, displacing liquid hydrogen. That made the engine somewhat complicated, since nothing is more different from kerosene than liquid hydrogen. The injectors, burners, combustion chambers, the proportion of liquid oxygen - everything is vastly different. And all that plumbing certainly weights a lot.

The TAN main advantage is that the kerosene injection is made in the exhaust / nozzle and not in the engine core (which remain an "ordinary" LOX/LH2 rocket engine).
That should make the engine design a little more easier - or, even better, the TAN "kerosene afterburner" can be added to an off-the-shelf LOX/LH2 rocket engine like the RS-68 or SSME.

I do hope tripropellant advocate Robert Salkeld lived long enough to see TAN, somewhat an accomplishment of all the pioneering work he did in the 70's (see here http://www.pmview.com/spaceodysseytwo/spacelvs/sld039.htm)
incidentally I'd like to know if there's a relation betwen Salkeld work and the soviet work on RD-701...
#4 by Archibald on 11 May, 2015 07:12
http://contest.techbriefs.com/2013/entries/aerospace-and-defense/3364
#5 by msat on 21 May, 2015 17:50
That's really quite interesting! Being able to substantially augment the thrust with such a low pressure propellant feed into the divergent section of the nozzle relative to primary chamber pressures is a huge win on its own, even if it didn't improve Isp, imo.