EA/18G Growler

[phreeky]

That effect, and corresponding formula, to somebody into cars (and most likely having done some naughty high-speed runs) should be quite obvious.

BUT (there is always a "but"), and I'm way out of my league here, as the speed of an aircraft increases (in this case, lets double it), the drag does NOT quadruple (as per that formula). Why? Well surely as an aircraft increases its speed, to maintain the required lift, it can reduce its angle of attack and hence the drag of an aircraft actually increases at a rate slower than that of what the formula you have presented would otherwise indicate.

By how much, stuffed if I know, you'd need to know the actual amount of drag induced by the lift generating surfaces of the particular aircraft - at least for a number of speeds to get an idea of the curve it follows (as it's sure to be a complex "curve").

 

[Jambo_100]

f 18

the F18 is an awesome plane but i think australia should have gone for the eurofighter. it supposed to be more advanced and more capable but im not sure. but the F18 is still an awesome plane!

 

[rjmaz1]

Im not sure if that specific formula is right. But from the solutions i remember at uni, the numbers i gave in the first example are pretty accurate, probably within 10% accuracy.

Double the drag on an aircraft and its speed would be roughly two thirds. Say 666km/h and 1000km/h.

Double the power and the speed will go from 1000km/h to around 1500km/h

But then another factor is exhaust velcity from the engine. At 1000km/h it may have enough thrust to theoretically reach 1500km/h but as the speed increases power/exhaust velocity decreases. So it may only reach 1400km/h for example.

It is very safe to say the F-35 will reach Mach 1 without afterburner. Everything points to the fact that it will.. and the rumours say that it does.

That effect, and corresponding formula, to somebody into cars (and most likely having done some naughty high-speed runs) should be quite obvious.

How could they even begin to estimate the power the engine is putting out at certain speeds?

Rpm compared to a dyno readout doesn't mean much as you can be at a certain rpm range at half throttle and be putting out less power than at full throttle at the same rpm and roadspeed.

With the Eurofighter clean speed is meant to be Mach 1.3, but with A2A config it cruises at Mach1. That decrease in speed suggests the drag has not doubled (100%) but has gone up around 50%. That a pretty large percentage increase in drag for very few weapons. The Suhkoi would be even worse.

 

[Grand Danois]

Im not sure if that specific formula is right. But from the solutions i remember at uni, the numbers i gave in the first example are pretty accurate, probably within 10% accuracy.

No it isn't. It only accounts for the subsonic flow regime.

If you look at the formula, you'll notice Cd is part of it, and it is not constant with velocity. See attachment for generalised graph of Cd for a fighter.

 

[phreeky]

How could they even begin to estimate the power the engine is putting out at certain speeds?

Well, same cars, different engines/gearing, and the top speed increases by SFA. The amount of drag increases pretty quickly.

As for an aircraft, similarly an engine design will work more efficiently at a certain speed, as will the lift surfaces, plus all the other bits sticking out are effected by the turbulance from each other - it's such a complex scenario, you aint gonna get a value close to the real thing without either a lucky guess or an extra-ordinary simulation.

 

[gf0012-aust]

It is very safe to say the F-35 will reach Mach 1 without afterburner. Everything points to the fact that it will.. and the rumours say that it does.

Where does it point to that? Every bit of data in the public domain remains black magic to the majority of the public. The only ones brave enough to extrapolate data are the FTE's, TP's and aviation engineers - and they are seriously keeping their counsel as they only have access to unqualified data (as a whole) and qualified data (at discretion level)

How could they even begin to estimate the power the engine is putting out at certain speeds?

Thats why they have test bed engines, simulations and (eg) parallel processing options.

At a really basic level, any Formula 1 Team is more than able to give you a complete diagnostic on how their engine behaves from the time it turns on to the time its switched off. At a test bed level, they're up there with some of the aviation companies as far as engine management at a real time level is concerned.

 

[Aussie Digger]

the F18 is an awesome plane but i think australia should have gone for the eurofighter. it supposed to be more advanced and more capable but im not sure. but the F18 is still an awesome plane!

Says who?

Fact is the current Block V Tranche I Eurofighter is a SIGNIFICANTLY less capable aircraft than a Block II Super Hornet.

The Eurofighter may INDEED become a very capable strike/fighter in future Tranche variants, should they come to pass, but they are not likely to in the timeframe that RAAF requires and in any case are unlikely to exceed the F-35 in overall capability, which is RAAF's preferred next generation combat aircraft...

 

[Big-E]

I wouldn't discount the R77 just because its never been tested in battle, neither has the F22.

You can't even begin to compare the testing involved in an American war bird to any Russian weapon system. The test hours, data collection, efficiency, computations, redundancy and reliability are far greater than anything the Russian industrial complex could hope to match. Just look at the Indian failure of the Krasnopal... both batches were total losses, millions gone.

I never said the R74 had higher off broadsigt than the AIM 9X. You said the X would be decisive, however there missile systems are comperable.

They are not comperable given the complexity of countermeasures and the AIM-9Xs ability to defeat these obstacles. It is in a class of it's own in regards to Russian systems.

You dont give the falnker driver much credit. He still has the ability to get his weapons pointed at you and employ them quicker than you can, apart from at slow speed. And allthough SH has the advantage in SA, i find it hard to believe that the Flanker driver would not have a good idea of were the SH was in most circumstances.

Is there any particular reason I should give an Indonesian Flanker pilot a second thought considering they don't even have a TRAWING set up for it? RAAF pilots are so far ahead of the competition they would dust them in their sleep. Russian pilots aren't any better considering I get as many hours working today as they get in a year of the cockpit. India is an ally as far as I'm concerned. PLAAF still runs their force like it's 1970.

If the Flanker was piloted by someone as capable as a USN avaitor the tide would turn in favor of the flanker WVR but the whole force concept is to prevent this from happening. BVR is several times in favor of the Rhino. Let me ask you, do you want to be in the Super Bug with the knowledge you have the most advanced highly tested weapon systems the world has to offer or do you want to go up in Russian equipment were 70% of their advanced systems fail on a random basis? I leave the choice to you.

What would the frontal M2 RCS of a SH be with 2-3 drop tanks and AAM's? In the ball park of a clean Flanker i would think.

Why would the SH go into combat trying to get an edge carrying drop tanks... that's why they're called drop tanks.

And yes this means in the frontal aspect detection range is lower but how much so? Without the exact performance data of the russian radars it would be hard to tell exactly but how could this be desisivly exploited? And what happens if the enemy has an AEW&C's capability, that advantage is then meaningless.

The performance of the APG-79 AESA is better than any potential adversary and in most cases they are better than their AEWACs to. Russians don't know the meaning of a passive aerial radar and will light themselves up like a Christmas tree. The Super Bug will have the advantage until the Russians can come up with more passive radars.

Hug the waives, do you mean fly at low altitude??? This deosent seem to be a desisive tactic for most sircumstances.

What would you know about it??? Did you not know Russian IR and semi-active seekers are easily confused with wave distortions and sea clutter? Of course you didn't... you thought Russian AAMs had a high kill probabilty at sea level.

Do you mean wingtip rails or all hardpoints? I have a hard time believing that under wing harpoints cant fire AAM's at super sonic speeds.

What happened to MRLs... that is what we use these days.

 

[Big-E]

Big-E will probably be able to give us some numbers on how fast a super Hornet can cruise at with 5 fuel tanks and with no fuel tanks. Would i be correct in assuming 500 knots without tanks and 300 knots with 5 tanks?

I still stand by my comment that even the higher powered suhkoi's will only just manage to reach the speed of the F-35. Current Suhkoi's will infact be slower than the F-35 but still much quicker than the Super Hornet.

When your carrying fuel tanks you really aren't in a big hurry to get where your going. The drag is fairly large with that loadout and you keep it at cruising speed. There is only so much stress your stores and wings can take. The more you push it the more you wear out the frame which is against procedure. If you have to push the envelope for a critical engagement you will dump your tanks sequentially as you go to reduce drag for increased speed. The cleaner you can get your frame the better.

 

[Big-E]

That just about does me...

I failed physics at a high school level, and even I know that your reasoning is totally... bunk! Can someone out there with a better understanding of this stuff help me out here!!!???

Geesh...

Magoo

Here goes...

Basic physics and fluid dynamics.

If an aircraft in clean config has a top speed without afterburner of 1,000km/h and its maximum dry thrust at that altitude is 30,000lb... then the drag of that aircraft is also 30,000lb.

As drag has an exponential increase with speed then if you add five refueling tanks and its airspeed does drops a third then that suggests the drag of the aircraft has pretty much doubled. In that case that would mean the drag of each dop tank would cosume over 5,000lb of thrust at 1,000km/h.

How do you get that from Drag = Cd x A x .5 x r x V^2?

Your calculations are so oversimplified and exaggerated they would tear the aircraft apart just by rolling it out to the end of the runway. nfloorl:

Very draggy indeed. Thats why the Suhkoi's will never supercruise with weapons. It will most likely sit around Mach 1 in the transonic region. This drag is also why the F-35 will travel faster with less power and will also be able to sit up around Mach 1.

The reason the Sukhoi will never supercruise is not because of a weapons loadout. It's due to the poor performance and efficiency of her engines.

To hammer home how fast the F-35 will be... The F-22 can cruise without afterburners at Mach 1.6 if you comepletely shut one engine its dry thrust will be halved. Does that mean the speed is halved? No drag is expenential so it will travel much quicker than half or Mach 0.8. The F-22 with ONE engine only could cruise at Mach 1.1~1.2.

The balance of thrust will be lost and the single engine will force the aircraft to pitch to a lower angle in order to keep from stalling. This will decrease your speed far greater than half. There is no way in hell any dual engined aircraft can go supersonic with one engine. Where do you come up with this non-sense? :unknown

The F-35 has one engine. Its one engine has more power than the F-22's and the aircraft is smaller and lighter. Even though its not as streamlined Mach 1 at dry thrust is completely realistic. It has such a large fuel fraction and with only one engine consuming that fuel it could sustain Mach 1 for the entire mission. Unlike the F-22 that has the same amount of internal fuel but now shared between two engines so the F-22 will probably travel long distances at transonic speeds not supersonic.

Do you really think fuel economy comes by turning off one of your engines? The one engine has to work much harder to keep the aircraft at the desired speed, your setting yourself up for bingo fuel before you ever get there. :haha

If you are the future of physics... heaven help us. :shudder

 

[Grand Danois]

Most of you have probably already read this from C4ISR.

Here it goes anyway, for those that haven't.

RAAF chief addresses capability concerns
By Paul Richfield
March 23, 2007

A planned acquisition of 24 Boeing F/A-18F Super Hornets by 2010 will ensure Australia’s air combat capability in the lead up to the introduction of the Lockheed Martin F-35 Joint Strike Fighter, according to the top Royal Australian Air Force (RAAF) officer.

Speaking March 23 at the Australian International Airshow at Avalon, Victoria, Air Marshal Geoff Shepherd sought to allay fears that the Super Hornet would come up short if forced to do battle with nations employing advanced Russian fighter designs, such as the Sukhoi Su-30.

“I flew the Su-30 in India and yes, it’s a big, fast, highly maneuverable airplane,” Shepherd said. “But it’s not a networked airplane like the Super Hornet. Still, the JSF is the main game for us, and the Super Hornet – not the F-111 – is the aircraft to take us there.”

No problems with the Super Hornet procurement are expected, Shepherd said, given the RAAF’s long experience with the first-generation Hornet and other U.S. programs. “We’ve got great support from the U.S. Navy and from the Pentagon,” he said. “We know the program office and we know the people.”

Shepherd emphasized that the RAAF’s air combat power is not a function of the Super Hornet, JSF or any other specific platform, but how all elements combine to support a multi-level net-centric warfare concept. “People, training, doctrine, facilities – all will play an equally important role,” he said.

And, although the Super Hornet and the JSF might not be able to fly as fast as some “fifth generation” fighters now in the works in other nations, advanced radars and weapons make the difference irrelevant, he said.

“Everything is geared toward engagements beyond visual range,” said Group Capt. Steve “Zed” Roberton, head of the RAAF’s air combat transition office. “The key is being able to get off the first effective shot and information dominance, not top speed, is the critical factor in that.”

“In a maneuvering fight, turning, pointing and bringing weapon to bear is more important than raw speed,” Roberton added. “Even the most ardent opponents of Super Hornet acknowledge that its [active electronically scanned array] radar is unmatched. As a ‘bridging’ aircraft, it gives us what we need to take us through 2020.”

Should Australia’s expected purchase of up to 100 JSFs slip to the right, the RAAF is prepared to adjust its plan, according to Shepherd. “We’re honoring the possibility of keeping the Super Hornets over their full life,” he said.

First-generation Hornets in the RAAF inventory will still have a key role after the F-18Fs arrive, according to Air Cdre. Mark Binskin, the service’s capability planning director. An upgrade to 71 first-generation Hornets will proceed as planned, he said, with funding assured for 49 “center barrel” fuselage replacements.

A determination on the final number of center barrel replacements is pending, however. “We’re reviewing those numbers but it’s expected that the ‘classics’ will still be with us in 2018,” Binskin said.

Regarding delays to the Boeing 737-based Wedgetail airborne early warning and control aircraft program, Shepherd described the situation as “irksome,” but one that nonetheless “allows us to get all the training and doctrine straightened out.”

---------------------

There is also this piece in C4ISR.

AESA radar key to Block II Super Hornets

(Good stuff they have on that site.)

 

[rjmaz1]

The balance of thrust will be lost and the single engine will force the aircraft to pitch to a lower angle in order to keep from stalling. This will decrease your speed far greater than half. There is no way in hell any dual engined aircraft can go supersonic with one engine. Where do you come up with this non-sense? :unknown

This is an example yes of course the plane will pitch over, but im saying that thrust wise the F-22 would be able to travel slightly above Mach 1 with one engine. This was to give a comparison to the JSF as it has one engine. I never said supersonic, i said Mach 1 which is transonic.

To test this you could run the engines at reduced power so that the dry thrust of both engines combined will reach the max dry thrust of a single engine. This would be more realistic but i simplified it by saying one engine. The F-22 will most likely exceed Mach 1 with the total dry thrust of a single engine.

Do you really think fuel economy comes by turning off one of your engines? The one engine has to work much harder to keep the aircraft at the desired speed, your setting yourself up for bingo fuel before you ever get there. :haha

If you are the future of physics... heaven help us. :shudder

You completely misunderstood what i was getting at.

The F-22 if it runs both engines at 100% military power will be burning close to twice as much fuel as the F-35 will at 100% military power. So the endurance of the F-35 will be much longer than the F-22. If the F-22 with 100% military power travelled twice as fast as the F-35 at 100% military power it would cover the same distance using the same fuel but get there in half the time.

However the F-22 does not travel twice as quick at dry thrust, probably a little over 50% quicker due to drag not being linear with speed. So the range at 100% military power will be higher in the F-35 than the F-22. Slow and steady wins the race. With the F-22 to get the most range they throttle the engines right back to slow the aircraft down so it can cruise effeciently at slower speeds. At these speeds they could have just used a single engine and ran it at maximum dry thrust instead, which is what the F-35 does. You loose the insane speed when you need it but it works well..

 

[gf0012-aust]

You completely misunderstood what i was getting at.

The F-22 if it runs both engines at 100% military power will be burning close to twice as much fuel as the F-35 will at 100% military power. So the endurance of the F-35 will be much longer than the F-22. If the F-22 with 100% military power travelled twice as fast as the F-35 at 100% military power it would cover the same distance using the same fuel but get there in half the time.

Good grief. It doesn't work like that. Both platforms have different thrust weight ratios for a start.

You can't use circle work analogies for this.

 

[Big-E]

This is an example yes of course the plane will pitch over, but im saying that thrust wise the F-22 would be able to travel slightly above Mach 1 with one engine. This was to give a comparison to the JSF as it has one engine. I never said supersonic, i said Mach 1 which is transonic.

You said she could cruise at Mach. 1.2 on one engine. Mach 1.2 means 95% of the airflow is supersonic. If any of the flow is supersonic your entering a whole new dimension. You also said she could cruise, well the scenerio you laid out would have the engine on afterburner... you do know what cruise means don't you? :unknown

To test this you could run the engines at reduced power so that the dry thrust of both engines combined will reach the max dry thrust of a single engine. This would be more realistic but i simplified it by saying one engine. The F-22 will most likely exceed Mach 1 with the total dry thrust of a single engine.

I think you did oversimplified it too much... funny how you corrected yourself yet still came to the same conclusion. :shudder

You completely misunderstood what i was getting at.

I'm pretty sure I got it...

The F-22 if it runs both engines at 100% military power will be burning close to twice as much fuel as the F-35 will at 100% military power. So the endurance of the F-35 will be much longer than the F-22. If the F-22 with 100% military power travelled twice as fast as the F-35 at 100% military power it would cover the same distance using the same fuel but get there in half the time.

However the F-22 does not travel twice as quick at dry thrust, probably a little over 50% quicker due to drag not being linear with speed. So the range at 100% military power will be higher in the F-35 than the F-22. Slow and steady wins the race. With the F-22 to get the most range they throttle the engines right back to slow the aircraft down so it can cruise effeciently at slower speeds. At these speeds they could have just used a single engine and ran it at maximum dry thrust instead, which is what the F-35 does. You loose the insane speed when you need it but it works well..

If the Raptor goes to 100% military power on one engine she will not be able to maintain the benefits of super cruise, she becomes just as gas guzzling as any other twin engined fighter aircraft. The F-35 has a huge efficient single engine and has much less mass than the Raptor. JSF will be several times more fuel efficient than the scenerio you paint... simulating engine failure is only used in training, not for fuel economy. :shudder

 

[rjmaz1]

I'm pretty sure I got it...

Based on that last post you definitely didn't get it...

Once again i said Mach 1.1~1.2. That is _NOT_ supercruise. I never said supercruise. An F-22 with only half the military thrust will _NOT_ reach supersonic speeds. It will however go close to reaching Mach 1 if not tip over into the transonic region. If it can reach Mach 1.5 with 100% dry thrust it can reach Mach 1 with 50% dry thrust as drag is not linear

The F-35 has a huge efficient single engine and has much less mass than the Raptor. JSF will be several times more fuel efficient than the scenerio you paint...

Though that is exactly what im trying to get across.

The F-22 being able to travel at Mach 1 with so little thrust suggests that the F-35 shouldn't have any difficulty at cruising around Mach 1. Again this is not supercruise. It will cruise at transonic speeds.

 

[Big-E]

The F-22 being able to travel at Mach 1 with so little thrust suggests that the F-35 shouldn't have any difficulty at cruising around Mach 1. Again this is not supercruise. It will cruise at transonic speeds.

The F-22 won't be able to meet it's thrust to weight ratio on one engine without going to burner at it's transonic cruise speed... that's my point that you never acknowledge. It would never reach Mach 1 even with the burner lit. Whatever point your making is moot because it has no basis in reality.

 

[jaffo4011]

Says who?

Fact is the current Block V Tranche I Eurofighter is a SIGNIFICANTLY less capable aircraft than a Block II Super Hornet.

The Eurofighter may INDEED become a very capable strike/fighter in future Tranche variants, should they come to pass, but they are not likely to in the timeframe that RAAF requires and in any case are unlikely to exceed the F-35 in overall capability, which is RAAF's preferred next generation combat aircraft...

aussie,can you define in what ways the sh is significantly more capable than the typhoon,please?

 

[Big-E]

aussie,can you define in what ways the sh is significantly more capable than the typhoon,please?

Reduced RCS, AESA radar, AIM-120D... I'll take the Rhino anyday.

 

[jaffo4011]

Reduced RCS, AESA radar, AIM-120D... I'll take the Rhino anyday.

i think we've been here before...however, iwould make the point that im sure the usaf wouldnt of bothered with the f22 if the sh was quite that good and i understand that the typhoon on manoevres in the us was found to be superior to the f22 in close combat.see the following quote.......

Just got a copy of International Air Power Review, Volume 20. It has an excellent article on the Eurofighter Typhoon and the real surprise came for me while reading the second page of the article (page 45 of the magazine). Typhoon has deployed to the US for tests by the Operational Evaluation Unit (OEU), presumably from England. In skirmishes with the F-22A, the Typhoon dominated the Within Visual Range engagements and apparently this really didn't surprise anyone because Typhoon is known for having outstanding agility. When it scored a radar lock on the F-22A at Beyond Visual Range, that caused quite a stir.

as for the aim120, id rather take the meteor thank you very much and amraam will do nicely for now!

reduced rcs?..what from the rcs of a train down to that of a bus?...the typhoon is pretty comfortably in the lead there too!

as such i wouldnt really put too many spondulas on the sh being an equal match to even a block 5 typhoon.its a great fighter,sure but fundamentally an old basic design which wont be able to be effectively upgraded for as many years as the typhoon,rafale,f22 or f35......it reminds me of the luftwaffe phantoms still in service....highly upgraded,effective but no matter how you look at it,its still a very old design! ...

 

[alexsa]

Reduced RCS, AESA radar, AIM-120D... I'll take the Rhino anyday.

..... and it does not have to wait for subsequent upgrades to be a strike aircraft. EF only has limit strike capability in its current iteration.