Where will aircraft engine be in the future?

Resister1976

Resister1976

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Can we witness the birth of four-stage variable cycle engine(Turbofan-Turbojet-Subsonic combustion ramjet-Supersonic combustion ramjet(Scramjet))?
 
A timescale of 'the future' leaves a heck of a lot of wiggle room. How far into the future?
 
There are a bunch i think, variable cycle, SABRE, reaction engines, scramjet, ramjet, detonation engine and probably a bonus but new aviation material created that weights less than 1/10 of aluminum where majority % of aircrafts are made of aluminum and titanium meaning thrust to weight ratio increased. Some I believe might give up sticking to variable cycle and some wont.
 
You act surprised? Just look at the 3 main fighter engines in service in the USA (and elsewhere) today:

F119 in F-22:
  • Initially developed from the Joint Advanced Fighter Engine (JAFE) program in the early 1980s (actual RFP was released in May 1983);
  • First flight in YF-22 (as YF119) October 1990
  • First F119 ground tests Feb 1993;
  • First Flight in F-22 Sep 1997; and
  • Still in service today.
F135 in F-35: (derived from F119)
  • First flight engine test runs December 2005
  • Still in service today and likely to be for the next 50+yrs (LM expect production of the F-35 to continue until 2040 at least).
F414 in F/A-18E/F/G:
  • Initially derived via GE GE-15 (1969) - YJ101 (1972) - F404 (1978) - F412 - F414 (1993)
  • Still in service today and expected to be for decades yet with production still underway.

What you tend to see are more evolutionary, incremental improvements rather than radical new technological developments.
 
On the other hand, it is at times when you think that a state of stasis will persist indefinitely when you can get the greatest shocks, for good or ill.
 
I see one of the biggest influences on performance being improved efficiency and better materials. Possibly some method of imitating the skin of particularly fast fish for boosting performance. Better fuels too.
 
During the five years of the WWII, the power of engines and speed of aircrafts increased as much as it did during twenty years of peacetime.

The conventional aircrafts and engines reached the limits marked in the original design and even surpassed them, very fast. The base for this huge achievement was exotic fuels, short lived artificially overpowered engines, propellers with four, five and even six blades and thinner wings with special sections of laminar flow.

Some pilots even ordered the paint on their aircraft polished to gain some speed. The limit had been reached and the industry was ready for the arrival of the turbojet and the arrowed wing.

And then the man discovered the existence of the demon that lived in the air…..
 
Engines for civil and military transport aircraft will probably become larger in diameter for added efficiency. From what I understand, the larger the bypass ratio, the more efficient the engine (these are extremely simple terms, and is not the only reason why engines are becoming ever more efficient.)

I also think that geared turbofans will become more common as well.
 
Starter-generators will become increasing more powerful.
A: to generate more electricity for ever more complex avionics.
B: Boost take-off thrust
C: Short-term boost if one engine quits.
 
riggerrob said:
Starter-generators will become increasing more powerful.
A: to generate more electricity for ever more complex avionics.
B: Boost take-off thrust
C: Short-term boost if one engine quits.
Click to expand...
True. In fact, in an associated manner, if we move outside the realm of gas turbines (for the most part), the biggest area there will be change/development will be in electric aircraft propulsion with piston engines and smaller turboprops (especially the PT6A/TPE331 level) potentially being under challenge. That said, whilst the technology may be there, it is an entirely different thing to see it accepted wide scale. Remember that the engines are only part of the picture: to see wide scale acceptance of new propulsion, one needs to either also see a wide-scale replacement of the airfares too and/or wide scale re-engining efforts. Both these may find reluctance in many operators unless there is some sort of incentive/mandate.
 
M88 studies started as early as 1977. As for EJ200, through XJ30 and 40 it is directly related to the RB199, itself related to the RB172 - reaching back as far as 1963 (from memory).

But nobody complains please. Rocketry has been stuck with hydrolox 460 seconds specific impulse since the Sputnik days or even before (Tsiolkovsky ?)
 
I suspect we will be seeing a lot more turboramjets and the like in the military sphere. Possibly also even more exotic stuff for certain applications such as ionolifters.
 
I have to say I have been surprised to see the scramjet finding itself a niche and role at least. For hypersonic missiles.
Only 10 years ago it was still at X-43 & X-51 level of development.
Only 20 years ago it was still badly burned by the X-30 - Orient Express fiasco.

And all of sudden, less than a decade ago... hypersonic missiles and weapons. All over the place !
 
Scramjets did take awhile to develop http://www.russianspaceweb.com/kholod.html

First flight test

Following years of theoretical development initiated in mid-1970s, the Turaev branch of the TsIAM institute successfully tested the scramjet engine at its Ts-16KV test stand, apparently the largest facility of its kind. These trials cleared the technology for actual flight tests. The first Kholod rocket lifted off from the Sary Shagan test range in Kazakhstan on Nov. 27, 1991, just a few weeks before the dissolution of the USSR. The vehicle reached an altitude of 35 kilometers and developed a speed of 1,653 kilometers per second or Mach 3.6. The hydrogen-powered scramjet engine logged a total of 27.5 seconds of firing during the flight.

In November 1994, NASA finally joined the Kholod program. During the same year, Department 101 at the KB Khimavtomatiki propulsion bureau, KBKhA, in the city of Voronezh took over the development of the scramjet engine, which was now designated 58L. (331) The engine was re-designed to withstand higher temperatures, which would result from sustained operation of the engine in a supersonic combustion mode.

A NASA-sponsored test mission, which featured an upgraded engine supplied by KBKhA lifted off on February 12, 1998. With the goal of reaching a speed of Mach 6.5, the Kholod vehicle accelerated from Mach 3 to around Mach 6.41-6.47, after successfully firing for record-breaking 77 seconds at a maximum altitude of 27.1 kilometers. (688, 331, 689) Ironically, despite its terrible economic woes in the 1990s, Russia became the first to fly a scramjet vehicle.
 
I doubt we will see just powerplants, but what about turborockets? I might have to go back through BSP 5 and find the exact definition again, I've been reading it, but a job that should have taken three months has taken me almost a year!

From what I remember, it is essentially a rocket that burned in a chamber, whose exhaust would pass over a turbine. This turbine would drive a shaft that would drive a compressor at the front of the engine. British designer contemplated its use back in the Sixties, as it gave better efficiency than a rocket, but engines like ramjets, scramjets and turboramjets were preferred.

I hope I'm not too far off o_O.
 
IMHO, the SABRE engine with that 'I DO NOT BELIEVE IT' implausibly efficient cooler core may be closest to real-world. IIRC, the cooler has been tested in US, proved better than expected...

Given a SABRE powered airframe may be ground run, launch from / return to runway under its own power, then either cruise Mach-5-ish to Antipodes in air-breathing mode or, as the aerospace variant, progressively engage rocket mode and fly to/from orbit, that's a seriously hard act to follow...

But, IMHO, SABRE and its bulky LH2 tankage sorta suits very big aircraft, Super-Concorde / Valkyrie scale...

If tamed, perhaps using tuneable Acoustic cavities / Helmholtz resonance, the 'rotating detonation' engine would seem a better fit to nimble 'fighter' aircraft and their 'wingman' UAVs...

en.wikipedia.org

Acoustic jar - Wikipedia

en.wikipedia.org en.wikipedia.org
en.wikipedia.org

Acoustic jar - Wikipedia

en.wikipedia.org en.wikipedia.org
https://en.wikipedia.org/wiki/Helmholtz_resonance
FWIW, there is a mechanically tuneable variety of Helmholtz resonators...
 

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