What is the most important in the air fighter to be better ,the powerplant or speed?

[Elmoktaeb]

What is the most important in the air fighter to be better ,the powerplant or speed?
and what is the most important the powerplant or range of the airfighter
and What is the most important too the service ceiling or powerplant

Generally What is the most important factor on the performance of the air fighter : the powerplant or the the speed or the range or the service ceiling?


and finally i want to know if the power/weight in an airfighter is higher than the other , does that mean that it is better?

 

[Ths]

The question is wrong.

The important parameters are thrust/weight ratio and specific fuel consumption.

By wrapping aluminium around that gives an envelope of range, lift and speed.

As speed is a first order function of engine, it does not give any meaning to ask what is most important.

 

[rjmaz1]

What is the most important in the air fighter to be better ,the powerplant or speed?
and what is the most important the powerplant or range of the airfighter
and What is the most important too the service ceiling or powerplant

Generally What is the most important factor on the performance of the air fighter : the powerplant or the the speed or the range or the service ceiling?


and finally i want to know if the power/weight in an airfighter is higher than the other , does that mean that it is better?

Wow so many questions! You could write a 100 page book answering these questions.

It all comes down to the phrase "first look, first shoot, first kill."

Aircraft are a compromise of many factors, the compromise depends on the mission required. Speed, service ceiling, stealth, range, cost, weight, agility you try increase some and the cost/weight goes up.

These days it seems stealth, avionics and speed is the most important factor that make a fighter good. Being able to detect the enemy from far away using an advanced radar while making it difficult for the enemy to detect you due to stealth is very hard to counter. Add speed to the mix and the enemy's reaction time is reduced and the effective range of the enemy's missiles are also reduced. Having all three like the F-22 ends up with it being a very expensive aircraft!

The second part of your question regarding engines. A cheap engine often has a lower thrust to weight ratio so it needs to be heavier and larger to produce the power required. If you had an unlimited budget then you'll have a high thrust to weight engine.

Also speed of an engine usually sacrifices specific fuel consumption.

A low bypass turbojet /fan usually has a higher exhaust velocity for high speed flight but with a low fuel consumption. Afterburners provide not only aircraft thrust but increased exhaust velocity this however consumes an extremely large amount of fuel.

A high bypass turbofan is a lower exhaust velocity and a much better specific fuel consumption. It allows aircraft to fly slow and long distances. However using afterburners on such an engine will still result in extremely poor fuel consumption. It will also have to use afterburners more often if you want to travel fast when compared to a lowbypass turbojet.

So if you want a supercruising fight you'd look for a lowbypass turbojet so you dont have to use afterburners to hit moderate supersonic speeds.

I hope this helps.

 

[Salty Dog]

In the by-gone days of the "pure interceptor" fighter, speed and thus the powerplant were extemely important. This is epitomized in the Mig-25 and Mig-31, true speed demons which were capable of little else, but were ideally configured for their interceptor missions.

Now-a-days fighters tend to be more "multirole" or "multimission" so due to trade-offs to be all-around efficient, speed is less important.

Having said that, technological advances in aerodynamics, materials, and engine designs have allowed newer generation designs to retain top end speeds relative to their earlier counterparts whilst assuming multirole capability.

 

[the_big_m_in_ok]

Comparing the F-16 to Mig-29

What is the most important in the air fighter to be better ,the powerplant or speed?
and what is the most important the powerplant or range of the airfighter
and What is the most important too the service ceiling or powerplant ...

All this can be subjective. Range and speed are dependent on the thrust rating and specific fuel consumption of the engine(s).
I read in a recent magazine article that the F-16 and the Mig-29 in equally talented pilots are equally maneuverable. However, the Mig-29 has large, thirsty turbofans compared to the F-16. With patience, the F-16 pilot can fight the Mig-29 to a dogfight draw if the F-16 can stay away from the nose cannon of the Mig-29. The Russian fighter has less range than the American fighter, even though the Russian fighter is still quite maneuverable. The Mig-29 has a larger wing, and that adds fuel volume, even though the engines burn a lot of fuel in afterburner, potentially reducing its range as an interceptor. Peculiar mission requirements color the picture significantly as well.
Short answer: Too many variables for me to say.

... Generally What is the most important factor on the performance of the air fighter : the powerplant or the the speed or the range or the service ceiling? ...

Powerplant(s) thrust directly affect both speed and range.
Here's a ratio: 8 times the gas thrust horsepower should give twice the speed, but would require an immense engine. This shortens range. A lot.
I can look up the algebraic formula later; it's not with me now.

... and finally i want to know if the power/weight in an airfighter is higher than the other , does that mean that it is better?

It can accelerate faster, but with a possibly higher wing loading for a bigger engine, the resulting lower ceiling can limit this advantage.
Then there's and smaller fighter that inherently has a lower wing loading and higher ceiling, due to the inverse cube law, but has potentially less fuel volume to be able to take advantage of the larger opponent. An individually higher engine compression also means more relative thrust and potentially faster speeds. But, having a lower fuel/wt ratio mitigates this advantage as well.

 

[Kilo 2-3]

It can accelerate faster, but with a possibly higher wing loading for a bigger engine, the resulting lower ceiling can limit this advantage.
Then there's and smaller fighter that inherently has a lower wing loading and higher ceiling, due to the inverse cube law, but has potentially less fuel volume to be able to take advantage of the larger opponent. An individually higher engine compression also means more relative thrust and potentially faster speeds. But, having a lower fuel/wt ratio mitigates this advantage as well.

Which is how we get fighters/interceptors like the F-104, and the MiG-21 (F-8 Crusader too?). Mach 2 straightline speeds at afterburner, incredibly rapid rates of climb, but which are desperately short-legged. Fitting a refueling probe can help rectify this somewhat.

Putting on tip tanks (later F-104s for example) or conformals can help rectify this somewhat. Big_M, what's your opinion on that solution? Is the extra fuel worth the drag they add?

 

[the_big_m_in_ok]

Which is how we get fighters/interceptors like the F-104, and the MiG-21 (F-8 Crusader too?). Mach 2 straightline speeds at afterburner, incredibly rapid rates of climb, but which are desperately short-legged.

Exactly. Afterburners shorten range, particularly in turbofans. Even at high altitude.

Fitting a refueling probe can help rectify this somewhat.

Right. But, there's the problem of logistics to provide tankers to service them. Generals and Admirals don't like this. Longer range aircraft are much more preferable.

Putting on tip tanks (later F-104s for example) or conformals can help rectify this somewhat. Big_M, what's your opinion on that solution? Is the extra fuel worth the drag they add?

It's still a conflicting heuristic.
The F-15 Silent Eagle comes with(I believe) standard conformal tanks, having added mounts for weapons. This adds drag, but increases range. (Although in the first F-15 design, speed wasn't affected greatly by conformal tanks.)
Individual mission requirements change the balance, sometimes quite a bit.

 

[weasel1962]

Re:

One important element. Logistics.

If it can't off the ground, its useless even if its the best in the air.

 

[the_big_m_in_ok]

One important element. Logistics.
If it can't off the ground, its useless even if its the best in the air.

Excellent. That, I think is the ongoing problem with newer Western military aircraft. Inflation is so severe, aircraft are unaffordable.

The newest titanium composites will increase aircraft T/W ratio, but if they're too costly, why buy them? Lighter, advanced technology engines often need extensive computer design work to optimize performance, which isn't cheap.

Still, bigger engines usually need bigger planes to fly them, which reduces ceiling and range. There are tradeoffs for this, which is how an engineer can make a living in R&D.

 

[PeterCrisp]

I hope you don't mind if I barge in with this extra question but watching a TV report about the sale of Eurofighters to Oman and they said one of the features the aircraft has been praised for is it's ability to go from the ground to 45,000 in 30 seconds which sounds pretty groovy to me.

I assume that's more helpful in a defensive situation where you just want to be able to get high so you can scan the area for threats from a high vantage point?

 

[the_big_m_in_ok]

I hope you don't mind if I barge in with this extra question but watching a TV report about the sale of Eurofighters to Oman and they said one of the features the aircraft has been praised for is it's ability to go from the ground to 45,000 in 30 seconds which sounds pretty groovy to me.

Are you sure about that climb rate? 40,000 ft in 30 secs (1/2 minute) = 90,000 ft/min climb rate.
They might have meant 40,000' in about 1-and-a-half or 2 mins.?

[ame="http://en.wikipedia.org/wiki/Eurofighter_Typhoon"]Eurofighter Typhoon - Wikipedia, the free encyclopedia@@AMEPARAM@@/wiki/File:Typhoon_f2_zj910_arp.jpg" class="image"><img alt="" src="http://upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Typhoon_f2_zj910_arp.jpg/300px-Typhoon_f2_zj910_arp.jpg"@@AMEPARAM@@commons/thumb/d/dc/Typhoon_f2_zj910_arp.jpg/300px-Typhoon_f2_zj910_arp.jpg[/ame]
(Click on the picture icon above to invoke the Wikipedia page.)

This source claims the rate of climb is over 62,000 ft/min. However, the maximum takeoff weight is 51,800 lbs. and the maximum thrust is only 40,500 lbs. It can't accelerate vertically, so I don't see how it can climb that fast.

I assume that's more helpful in a defensive situation where you just want to be able to get high so you can scan the area for threats from a high vantage point?

You bet. The SR-71 and Mig-25/31 are successful recon aircraft because they fly so high.

 

[kato]

I've seen 50,000 ft/min (regular) stated in other sources. 62,000 ft/min is apparently the max climb rate achievable, which depends mostly on altitude and forward speed.

Ground to 40k ft is 90 seconds (with 4 AMRAAM, 4 ASRAAM, 2x 1000l drop tank).

 

[the_big_m_in_ok]

I've seen 50,000 ft/min (regular) stated in other sources. 62,000 ft/min is apparently the max climb rate achievable, which depends mostly on altitude and forward speed.

Ground to 40k ft is 90 seconds (with 4 AMRAAM, 4 ASRAAM, 2x 1000l drop tank).

Quite possibly. Your post got me thinking; and then I remembered the F-15 and Mig-25 had the world time to altitude records for years. However, the average for the whole distance wouldn't reflect the initial rate from the runway surface.

 

[Chrisious]

A good study would be the old English Electric Lighning, which seems to hold a record or two still. Couple of videos included, including a slightly low fly past and verticle climb, note the odd overwing fuel tanks. Believe semi-officially it has been taken to 88,000 feet, though this is taken from wikipedia.

[nomedia="http://www.youtube.com/watch?v=g9DPsCx5NgE"]YouTube- fly the English Electric Lightning supersonic fighter jet[/nomedia]

[nomedia="http://www.youtube.com/watch?v=7S7Mj33jhek"]YouTube- Lightning F6 very low flying[/nomedia]

Also quite a good film here (not sure if this will play) 3 minutes in - sorry.

[nomedia="http://www.youtube.com/watch?v=BVIotFO0a0w"]YouTube- Wonders of the Solar System, Episode 3 (Part 1/6)[/nomedia]

 

[the_big_m_in_ok]

A good study would be the old English Electric Lighning, which seems to hold a record or two still. Couple of videos included, including a slightly low fly past and verticle climb, note the odd overwing fuel tanks. Believe semi-officially it has been taken to 88,000 feet, though this is taken from wikipedia.

YouTube- fly the English Electric Lightning supersonic fighter jet

YouTube- Lightning F6 very low flying

Also quite a good film here (BBC) not sure if this will play.

BBC iPlayer - Wonders of the Solar System: The Thin Blue Line

Very good. Here's another straightforward article. Click on the picture:
[ame="http://en.wikipedia.org/wiki/English_Electric_Lightning"]English Electric Lightning - Wikipedia, the free encyclopedia@@AMEPARAM@@/wiki/File:Lightning.inflight.arp.750pix.jpg" class="image"><img alt="" src="http://upload.wikimedia.org/wikipedia/commons/thumb/2/2d/Lightning.inflight.arp.750pix.jpg/300px-Lightning.inflight.arp.750pix.jpg"@@AMEPARAM@@commons/thumb/2/2d/Lightning.inflight.arp.750pix.jpg/300px-Lightning.inflight.arp.750pix.jpg[/ame]


The first prototype flew in 1959, so, for the time period, the Lightning had impressive performance.

Here would have been a good one:
F/A-18 Hornet - Wikipedia, the free encyclopedia
The 'L' version would have weighed about 7,700 lbs empty. Putting the newest F414's from the Growler in it would have giving it a paint-pealing climb rate. I believe this version, and the present F-22, could reach 50,000'-60,000' in less than 1 1/2 minutes.

 

[Ananda]

It all comes down to the phrase "first look, first shoot, first kill."

Aircraft are a compromise of many factors, the compromise depends on the mission required. Speed, service ceiling, stealth, range, cost, weight, agility you try increase some and the cost/weight goes up.

These days it seems stealth, avionics and speed is the most important factor that make a fighter good. Being able to detect the enemy from far away using an advanced radar while making it difficult for the enemy to detect you due to stealth is very hard to counter. Add speed to the mix and the enemy's reaction time is reduced and the effective range of the enemy's missiles are also reduced. Having all three like the F-22 ends up with it being a very expensive aircraft!

Gent's,

Seems to me the disscussion on this thread so far focusing more on the raw power of the engine, the aerodynamics, however besides rjmaz, seems you guys (coorectme if I'm wrong). put little emphasis on the electronics and sensors.

If two opposing force one equiped with lattest 4th gen like Grippen, F16, F 18, Su 30, Typhoon, facing another opposing force equiped with only the likes of F 5 but supported with sophisticated electronics aphratus inculding, BVR capabilities (for Inboard sensors), formidable long range ground sensors, ECM, AEW planes (for supporting snesors)..
Will the opposing force who will conducted offensive strategies since it has 4th gen aircraft (however relly only with that 4th gen fighthers) really gained the advantages..???

In sense I don't think in this scenarios those 4th gen fighthers will have certaint advantages facing with a modified 3rg gen but covered with formidable electronics support.
Just showing that in this days Electronics seems put more weights that can counter the disadvantages in the form of engine power, agility, and range.

 

[gf0012-aust]

actually, it's training before it's technology.

I'd point out that in tacair training instructors with far less capable platforms have bested current gen platforms.

get the training right before you focus on the tech. The latter means zip if the basics and decent craftwork aren't in place

 

[Chrisious]

Ananda.

Dare say cost does play a big part in modern designs can't imagine anyone wanting a fleet of 2000 fuel burners like the old Lightning stealthy or not. Clearly fly by wire was the way to go, and has obviously freed up the pilot for better weapons systems. Obviously F-16's and the Super Hornet have lead the way to the present day. Canards are interesting though not sure how far these will be taken forward.

 

[Kilo 2-3]

Ananda.

Dare say cost does play a big part in modern designs can't imagine anyone wanting a fleet of 2000 fuel burners like the old Lightning stealthy or not. Clearly fly by wire was the way to go, and has obviously freed up the pilot for better weapons systems. Obviously F-16's and the Super Hornet have lead the way to the present day. Canards are interesting though not sure how far these will be taken forward.

In my mind canards will not become a universal feature on future Western fighter aircraft. The Russians are a different story (they seem to prefer fairly agile platforms), and the Swedes value canards as a means of improving short-field capability; but in most other fighter-building nations it seems like there's an overall trend away from canards and the tactical and design approaches which would encourage their development.

However, one approach which might be developed further would be the addition of canards as an aftermarket feature (like the Swiss did to their Mirages) or to go with a compromise solution like movable LERX (what the T-50/PAK-FA has). The latter might be a possible modification for Super Hornets, although their slow-speed, high AoA handling is impressive already.

Just my inexpert two cents on the issue.