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-   -   More thrust - is it really transformative ? (https://www.pprune.org/military-aviation/570572-more-thrust-really-transformative.html)

Fonsini 13th Nov 2015 17:03

More thrust - is it really transformative ?
 
Bear with me on this one.

I have heard tell that the GE powered F-16 is a completely different beast to the lower powered PW versions of that handy little aircraft, also that the jump in thrust from the Lightning F.2 to the F.3 made a good aircraft great in pure aerodynamic terms.

So now I see that the EJ200 as used in the Typhoon is currently under development for a phased increase in performance in the form of the EJ2x0 to a 27,000lb thrust motor which will represent a 30% increase in available thrust over the current model.

So just how "transformative" is this likely to be - does it make THAT much difference - personal observations from experienced FJ pilots who went through the same evolutionary engine process on other types much appreciated as ever.

msbbarratt 13th Nov 2015 18:03

I'm no pilot, but from what I saw of Typhoons playing around at a hot'n'high airstrip in North America and chasing F18s out of the sky, I'd say that it wasn't exactly short of thrust to begin with.

Flap62 13th Nov 2015 18:09

While more power is always a good thing i would be surprised if Typhoon in its current incarnation needs it. Start hanging Stormshadow and multiple PW on it and I'm sure an increase in dry thrust wouldn't go amiss though.

KenV 13th Nov 2015 18:38

Is more thrust transformative? Maybe, maybe not, but..............

The USAF A-7s with the higher thrust TF-41 engine (derivative of the RR Spey) performed much better than the early USN A-7s with the TF-30.

The F-14D with the higher thrust F110 engine (and also much more flexible engine) is what made the Super Tomcat super and made it a much better airplane than the earlier version.

The F-8U Crusader 3 with the much higher thrust engine drastically changed the Crusader 2 in many ways.

The A-4SU Super Skyhawk with the higher thrust F404 engine really was "super" compared to the original Skyhawk.

The F-5E (which became the F-20 Tigershark) with the higher thrust engine significantly improved the venerable Tiger.

And the JAS 39 Gripen E with the higher thrust F414 engine is reportedly going to significantly transform the Gripen.

And although in a totally different class, putting much higher thrust CFM-56 engines on the KC-135 truly did transform that big old jet.

Bob Viking 13th Nov 2015 19:39

Not to forget...
 
None of these can be considered to be as ground breaking as the transformation seen on the Sepecat Jaguar when it progressed from the Adour 102 through the 104 to the 106. It changed the aircraft from an underpowered beast into a...

I'll let the comedians on this forum fill in the rest.

Whatever they come up with though it won't change the fact that it was an absolute blast to fly.

BV:ok:

zero1 13th Nov 2015 19:40

India is in the process of looking for a new engine for the Jaguar, which has always been considered underpowered. It will be interesting to see how that aircraft will be improved.

Nevertheless, one should also remember you need to improve reliability and fuel burn as part of the upgrade package... No point in increasing thrust and run out off fuel before you can complete your mission.

PersonFromPorlock 13th Nov 2015 20:42

Every little bit helps. Takeoffs out of Andersen (Guam) on 06R in a B-52G (8 x 13,750 lbf wet) were no biggy, but B-52Ds (8 x 12,100 lbf wet) sometimes popped off the overrun and disappeared over the edge of the cliff (instant 600 ft of altitude), not to be seen again until they struggled back up level a couple of miles out.

Courtney Mil 13th Nov 2015 21:05

I would go slightly further than KenV's response in that I would remove his "maybe not" bit. Sorry, Ken.

Purely off the top of my head (perhaps through my hat), I cannot think of any case where more thrust would be anything but beneficial to performance, provided it does not mean excessive idle thrust, significantly reduced stall margins or degraded engine robustness.

As airframes evolve, they invariably end up getting heavier and hauling more drag. Furthermore, energy manoeuvrability is a massive factor in weapons range and Pk - sorry for my AD slant there, but it does apply to most air launched weapons.

Must dash, news coming through about attacks in Paris.......

Miles Magister 13th Nov 2015 22:12

Too much power (thrust) is never enough!

O-P 13th Nov 2015 22:18

I seem to remember that increasing the thrust of an afterburning engine will 'usually' result in increased reliability (lowered RPMs, temp margins etc), and a reduction in fuel consumption/increased endurance...less need to tap the 'burner to get the required thrust.

I've never flown an aircraft that had too much power... don't think one exists.

ShotOne 14th Nov 2015 09:00

"..don't think one exists". Only if you're playing top trumps, OP. For anything else it's a trade-off, as zero says, it doesn't help at all if you run out of fuel before completing the mission. What made the Buccaneer a great aeroplane was the manufacturer's rejection of the Navy demand for more powerful -and thirsty -afterburning engines.

wanabee777 14th Nov 2015 09:58

Swapping the Allison for a Merlin certainly transformed the NA-73.

Tourist 14th Nov 2015 10:14


Originally Posted by ShotOne (Post 9180500)
"What made the Buccaneer a great aeroplane was the manufacturer's rejection of the Navy demand for more powerful -and thirsty -afterburning engines.

Hmm, that depends.

My dad was on the first Bucaneer sqn that stood up and he doesn't have many good words for it.

"utterly gutless" were two of them.

I think the later more powerful versions were better.....

Minnie Burner 14th Nov 2015 10:21

No need for minnie burner if you already have enough dry thrust!
Lightning F2 to F3: not really significant as the F3 was a bit heavier and grew into the F3a (or Mk6). Drivers of the F2a were happy with its performance, despite the older engine, better fire integrity and the good, yes good, endurance. Especially on one engine. Now that's enough thrust.
Shot one: What actually made the Bucc a decent jet was dumping the Gyron Juniors.....
As for the Jag: a better engine and a better wing would have made a difference, perhaps. Oh, and a radar and.......

Martin the Martian 14th Nov 2015 11:12

In thrust we trust.

I believe the Buccaneer S.1 had to be launched with only a partial fuel load due to the Gyron Junior's poor performance, with a buddy tank-equipped Scimitar to top it up once airborne.

megan 14th Nov 2015 11:36


Swapping the Allison for a Merlin certainly transformed the NA-73
Depends what you mean by "transformed". The Allison was the better engine for the role in which that particular model was used, whereas the Merlin gave the aircraft a completely different ability, high altitude escort.

Schnowzer 14th Nov 2015 12:56

The F15E had a thrust bump from the C model so that it had essentially the same performance with conformal tanks and pods on as the clean F15c. It made it a magnificent beast in training fit but also meant it could do the war role designated for it without issue. The Typhoon will be awesome with more thrust, a burner climb clean would be a real laugh.

Busta 14th Nov 2015 16:01

I seem to recall that sometimes full reheat wasn't enough and idle boards was too much. Ho hum!

Schiller 14th Nov 2015 16:10


Originally Posted by Martin the Martian (Post 9180611)
In thrust we trust.

I believe the Buccaneer S.1 had to be launched with only a partial fuel load due to the Gyron Junior's poor performance, with a buddy tank-equipped Scimitar to top it up once airborne.

Not really true, M the M. We used to launch with full internal fuel - with a catapult launch TOW was never an issue. But the SFC of the beast was appalling and we used a Scimitar to top up about 25 mins after launch to give us a decent range.

KenV 16th Nov 2015 18:25

No apologies needed. And I get what you're saying. But I was focussing on the "transformative" adjective. More thrust is always "better", but will it always "transform" an airplane? Often yes. But always?

For example, the higher thrust F414 in the F/A-18E/F Super Hornet resulted in a Super Hornet with only marginally better aero performance than the Classic Hornet, and even that is arguable. What made the Super Hornet Super was the increased fuel capacity and all the new systems that the Super Hornet could accept relative to the classic Hornet. In my view, the bigger engine was needed to maintain aero performance levels, not transform them.

In my opinion, USN would have been better off going with the Super Tomcat rather than the Super Hornet. The Super Tomcat had better performance, better range, and better endurance than the Super Hornet, and could accept essentially all the systems the Super Hornet ended up with, and would have cost much less to develop. But it appears that politics won out on that one.


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