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How to increase engine Thrust?: Project

RameeX Xaved

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Hi guys..sorry for this interruption but I have to consult some good proffesional aviation engineers coz I'm planning to participate in the Intel competition (held in USA) and the title I chose is how to increase the wieght to thrust ratio of an engine... Please only serious people reply to this topic who could really help me..

Thanks
 
hi there ! glad you joined the forum... are u the the person who asked me on orkut and i told u there were great people here that will help u?

well atleast tell if its gonna be fitted in a small plane of what dimensions?
engine will also be on some uniform standerds interms of weight, dimensions, materials used, general output[thrust]?what do u have at the moment?any pictures?

give the links of whatever sites u know of... [edit your first post with complete info]and im sure many people will help u out
the mods, pilots and engineers here are very informative and cooperative..
 
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No offense "Munir" but he did mention that he requires serious replies from serious people only ;p
 
Hi guys..sorry for this interruption but I have to consult some good proffesional aviation engineers coz I'm planning to participate in the Intel competition (held in USA) and the title I chose is how to increase the wieght to thrust ratio of an engine... Please only serious people reply to this topic who could really help me.
Well, to increase thrust to weight, you either increase the thrust or decrease the weight (amazing right?). There are so many ways of doing both, both well-established and research-level. I'll try to give you some pointers based on what little I've picked up thus far. In my company, we mostly only deal with control software testing for Pratt and Whitney and other commercial engine manufacturers, but the same basic concepts apply to military spec engines as well.

Thrust

- The absolute best way to increase thrust is to determine and achieve the optimum air-to-fuel ratio (optimal for power, not fuel efficiency). This optimum rate varies with speed, altitude, etc., therefore, from an engineering perspective, you must develop extremely detailed requirements such that the right operation level can be determined. To achieve optimum air-to-fuel levels, you can use various techniques, such as inlet design (ex. Divertless Supersonic Intake), variable fuel injection (like in most performance cars) etc. There are literally hundreds of ways to optimize the air-to-fuel ratio for max power. I leave it to you to research them.

- Another simple way of increasing net thrust is to reduce drag. This required an understanding of aerodynamics, which I'm guessing is not what you are interested in.

- There are also many engine specific ways of increasing thrust-to-weight ratio. Therefore, it would be beneficial if you told us what type of engine you are interested in. It could be one of many types of air-breathing engines; turbofan, turboprop, turbojet, ramjet, scramjet, rotary, piston etc. all of which can be used in aircraft. Of course, there are also non-air breathing ones, aka, rocket engines, which are very powerful as it is.

Weight

This is pretty straight forward (theoretically). Ditch the high-density metals, and adopt composites or aluminum wherever possible. Of course, you need to make sure the engine still meets the requirements and constraints (ex. cost and tolerance, respectively). The same goes for the aircraft, the lighter the aircraft, the greater the TWR. There are various established and under-research ways of achieving weight reduction as well.
 
It could be one of many types of air-breathing engines; turbofan, turboprop, turbojet, ramjet, scramjet, rotary, piston etc. all of which can be used in aircraft.
To further muddy the water, the SR-71's engines can rightly be considered a hybrid -- a turbojet in front of a ramjet.

The SR-71* Pratt & Whitney JT11D-20B J58 Engine
The J58 was a variable cycle engine which functioned as both a turbojet and a fan-assisted ramjet. Bypass jet engines were unknown at the time, but Ben Rich later described the engine as "Bypass jet engine by air withdrawal".[2] At Mach 3.2, 80% of the engine's thrust came from the ramjet section, with the turbojet section providing 20%.[3] At lower speeds, the J58 operated as a pure turbojet.
When I was at RAF Upper Heyford, I had friends who were maintainers to Det 4's SR-71s at RAF Mildenhall and everyone, especially the PW tech rep, considered the J58 to be a hybrid. Sometimes when I listened to their talks and the subject turned to the engines, it clarified a lot of troubleshooting issues once both sections of the engine is clearly distinguished. Without more details, the hybrid approach may be the best option.
 
Best case study at this moment is Indian LCA project, which is facing new problem which is weight and thrust.(Indian DRDO working on either to reduce weight of install new engine) Try google, lot of material available...
 
To further muddy the water, the SR-71's engines can rightly be considered a hybrid -- a turbojet in front of a ramjet.

The SR-71* Pratt & Whitney JT11D-20B J58 Engine
When I was at RAF Upper Heyford, I had friends who were maintainers to Det 4's SR-71s at RAF Mildenhall and everyone, especially the PW tech rep, considered the J58 to be a hybrid. Sometimes when I listened to their talks and the subject turned to the engines, it clarified a lot of troubleshooting issues once both sections of the engine is clearly distinguished. Without more details, the hybrid approach may be the best option.
Indeed.

General Electric introduced variable cycle technology on the YF-120 design. Pratt & Whitney, however, during development of the ATF engine (later the F-119 engine) decided against this technology because of weight and complexity penalties. It was Pratt & Whitney that had extensive experience with this type of technology as its J58 engine, which powered the legendary SR-71 Blackbird, was based on it. The advantage of variable cycle technology is that it allowed the engine to operate as a turbofan at subsonic speeds, but at supersonic speed it allowed the engine to operate as a conventional turbojet, which increases fuel efficiency.

Source:
Joint Strike Fighter
Design and Development of the International Aircraft
Gerard Keijsper - 2007


Note:
- In case of the SR-71, VCT allowed the engine to function as a turbojet at subsonic and as a turbo-assisted-ramjet at supersonic speeds, as gambit rightly pointed out.
- The YF-120 engine was General Electric's entry into the Advanced Tactical Fighter Engine (ATFE) program, which was aimed at developing a next-gen engine for the next-gen Advanced Tactical Fighter program (ATF, now the F-22 Raptor).
- GE's YF-120 design lost out to the YF-119 engine design by Pratt & Whitney for the ATFE program.
- Both the F-119 and the YF-120 engines were also entered in the Joint Advanced Strike Technology (later renamed the JSF) engine development programs, as the upgraded F-135 and F-136, respectively.
- Engineering is amazing.
 
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eat refried beans!:rofl:
sorry guys couldnt help it!:rofl:
 
eat refried beans!:rofl:
sorry guys couldnt help it!:rofl:
That's funny.
But it amy also be the most cost effective way to increase thrust. Heck, if you eat enough beans, you may not even need an engine!
bacche ki jaan le lenge yeh log, knowledge de de ke:D
The bacha seems uninterested in what we have to say. But it's alright.
 

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