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Future powerplants

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posted on Jun, 30 2009 @ 03:18 PM
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Hopefully this thread can bring together a number of disparate approaches and collect information on the next generation powerplants for the next generation narrowbodies (and subsequent designs).

It also may direct the readers towards the real battleground between the big two (thats Airbus and Boeing); by comparison the B787 and A350 are mere sideshows.




As most already know, the current narrowbody market consists of the Boeing 737 and the Airbus A320. Both powered by similar turbofan engines, the 737 having a bypass ratio in the low 5s, the A320 having a bypass ratio in the high 5s... with the core overall pressure ratio (OPR) nearly 33.


Now, looking forward, the only competition for these two is that is currently on the drawing board is Bombardier's CSeries.

Recently, both Boeing and Airbus have indicated they wish to hold off on the narrowbody replacements until the 2022-ish timeframe... due to both engineering resource availability and engine improvements.


Some of you in the know will be aware of the NASA 2025 or ACARE 2020 goals, namely:
- CO2 reduction by 50%
- NOx reduction by 80%
- Perceived noise by factor of 4 (6 PNdB)


Now, simply put, no-one is going to meet these goals without a paradigm shift in engine technology... so what are the contenders?

It is worth noting, that a reduction of fuel burned during cruise is accompanied by a reduction in CO2 emissions, but rising OPR can rise NOx.


1. The Ultra high bypass ratio turbofan. (UHBPR)

Having a bypass ratio of over 10, this is the closest to current technology, however some serious modifications are still required. Put simply, the bigger the fan, the slower it must turn, and the turbine speed must be matched to this. There are two means of matching turbine speeds, using triple shafts (Rolls-Royce) or using a gearbox (Pratt & Whitney).

The geared PW1524G PurePower has been selected as the engines for the Bombardier CSeries. It has a bypass ratio of approximately 13, and Pratt are targetting fuel savings of 20% relative to the newer A320/737s[1]. Information on the OPR is not yet available.

Current research in the field includes the likes of LeapX, where CFM are targetting similar improvements to the P&W geared turbofan concept.

It is also worth noting Pratt envisages improvements of 1% specific fuel consumption per year, and sees the geared fan as a genuine alternative to the propfan.


2. The ducted fan

An evolution of the UHBPR engine, due to further increasing bypass ratio a drastic reduction in bypass nacelle length is required to reduce nacelle weight to acceptable levels.

The mechanical problems posed are similar to the UHBPR engine[2].

Pratt & Whitney and NASA were working on an Advanced Ducted Prop (ADP), but the program has been shelved[3].


3. The Propfan

Seen as the great white hope of many propulsion engineers, even back in the 1980s, experimental propfans could half the fuel consumption relative to an in-service aircraft (Boeing 767). This is mainly due to a propulsive efficiency of over 80% at cruise Mach numbers (relative to ~65-70% for a turbofan)[4][5].

However, propfans are loud, and result in a rise in noise relative to current designs. Current research in the area include 'Clean Sky', in which Rolls-Royce is a major particpant, as well as the restarting of the old GE36 unducted fan/open rotor research between NASA and general electric[6].





[1] Aviation today

[2] Flight Global

[3] Forecast International - word _/url]

[4] Hünecke, K., "Jet Engines: Fundamentals of Theory, Design and Operation", Shrewsbury: Airlife, 1997

[url=http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19820011304_1982011304.pdf][5] NASA Contractor report 3505 - pdf


[6] Aviation Week



So now anyone with an interest in Boeing and Airbus' future knows roughly what to hunt for to ascertain where they are heading... if you find anything of interest, I would greatly appreciate it if you'd post it here!


[edit on 30/6/09 by kilcoo316]




posted on Jun, 30 2009 @ 03:29 PM
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Before the demise of Eclipse Aviation we were seeing Pratt & Whitney Canada PW600 series a family of very small turbofan engines being developed for this new family of very light jets



PW610F Specifications:
Take-off Thrust (lbf) 900 (4 kN)
Flat-rated to: >ISA+10C
Dry Weight (lb) 259.3
Length (in) 45.4
Fan Diameter (in) 14.5


I was starting to wonder just how small they could get with more research



Eclipse 400

[edit on 30-6-2009 by DaddyBare]



posted on Jun, 30 2009 @ 04:06 PM
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reply to post by DaddyBare
 


Thinking of which.

What about going back to multiple engines, instead of 2 large engines what about 4 or 8 small engines.

All engines could be used for takeoff, climb and acceleration then powered down during cruise. Then air restarted during descent for reverse thrust or go around.

Oh I know why, A 4 engined aircraft has twice as many engine failures as a 2 engined aircraft.



posted on Jun, 30 2009 @ 05:10 PM
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reply to post by lightchild
 


Maybe something like this

What your looking at is a crazy idea called a WIG plane.. scientists from Tongji University in Shanghai developed/designed a new model of the famous but largely unknown "wing-in-ground" (WIG) plane, Reuters reported, This plane, which can carry up to 4 metric tons (nearly 9,000 pounds), flies just 18 inches over the surface of the water, yet manages speeds of up to 180 mph.

To achieve these numbers, WIG planes use a technique called "ground effect" to achieve a high lift/drag ratio. Wings traveling close to the water (or ground) feel an extra lift by a cushion of air compressed underneath them. This enables the planes to carry extremely heavy loads while using significantly less fuel..

These new smaller more efficient engines could have made some remarkable changes to WIG development... But who knows what will happen now... to bad might have changed the way we travel uh

.For more Info on WIG's

[edit on 30-6-2009 by DaddyBare]



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