Forum: F-35 Lightning II

Absolute fuel isn't a good way to measure range. The most accurate way to measure range based on fuel, is the fuel fraction, or percentage of the plane's weight that is fuel. Example, the F-15 carries far more fuel than the F-16, but the F-16 has longer range. Reason: the F-16 has a higher percentage of fuel.

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Elite Joined: May 29, 2006 Posts: 640 Status: Offline

LWF wrote:

Absolute fuel isn't a good way to measure range. The most accurate way to measure range based on fuel, is the fuel fraction, or percentage of the plane's weight that is fuel. Example, the F-15 carries far more fuel than the F-16, but the F-16 has longer range. Reason: the F-16 has a higher percentage of fuel.

Well, yes, if you had read my earlier posts you would have seen I did exactly that. The F-35's percentage of fuel load vs. empty weight is almost twice that of the F-16.

Elite Joined: Nov 27, 2004 Posts: 535 Status: Offline

http://www.jsf.mil/downloads/documents/ ... Review.PDF

http://www.jsf.mil/downloads/documents/ ... Review.PDF

Idesof wrote:'And I still can't get over that fuel load: 18,500lbs! ..... AND a large internal armament load. A miracle of engineering in my book.'
He he Idesof, first I thought the same, but I saw the X-35 parked side by side with a F-16, if the F-16 is a sleek Cheetah than the X-35/ F-35 is a Rhino or Hippo. The F-35 has a very volumeous fuselage, because of the F-35Bs' liftfan the fuselage needs to be wide: advantage= a lot of internal fuel, disadvantage= the aerodynamic qualities are decreased.

Elite Joined: May 29, 2006 Posts: 640 Status: Offline

locum wrote:

Idesof wrote:'And I still can't get over that fuel load: 18,500lbs! ..... AND a large internal armament load. A miracle of engineering in my book.'
He he Idesof, first I thought the same, but I saw the X-35 parked side by side with a F-16, if the F-16 is a sleek Cheetah than the X-35/ F-35 is a Rhino or Hippo. The F-35 has a very volumeous fuselage, because of the F-35Bs' liftfan the fuselage needs to be wide: advantage= a lot of internal fuel, disadvantage= the aerodynamic qualities are decreased.

Yes, unfortunately, that is a disadvantage: the F-35 is not a pretty aircraft by any means (better than the F-32, though, which was one ugly mofo). However, given what areodynamicists can now do with computer engineering, the F-35 is probably more aerodynamically efficient than the Viper even if it looks, as you say, like a Rhino (which I suspect will become its nickname among pilots, or something like it). "Looks right, flies right" used to be the axiom, but that probably doesn't apply anymore. Not always true, though. Look at the British Lightning, one of its two namesakes: that was one ugly plane, and yet apparently was highly maneuverable. Had a range of about 15 NM, though, only slightly better than the F-18! Anyway, I'm babbling.

LOB

I think you are mixing max continuous use with off design conditions - not the same thing.

Prior to a cat shot the engine is stabilised at the desired power setting either dry or AB.

Containment is one aspect which is being tested, I suspect that you have never been involved in rotor burst testing.

Here is a link to show just some of the testing being done: http://www.dcmilitary.com/navy/tester/1 ... 769-1.html

LordOfBunnies wrote:

I'm not really sure about how everything work with this, but it may also not always be in full Mil. thrust all the time. The thing is good at full Mil. thrust, but if you're trying to putter along and extend range, this may not be best. I couldn't say exactly, need more schooling. The more advanced the engine, the lower the SFC almost always. This may have a higher bypass ratio than the F100/110 which would make it much more efficient. It will cause longer spool up (more spinning mass), but hopefully not that much as this thing is going off a carrier.

As for the 35B, I'd be worried mostly about maintenance on the lift fan. I know that maintenance is good, but if the thing breaks and throws a blade... the pilot is dead. I belive the tech to make it safe is there, but it may take out a little while to work the bugs out unfortunately.

With the new EMALS launch system, it may have enough muscle to throw F-35s into te air without them needing a/b.

Elite Joined: Dec 19, 2005 Posts: 615 Status: Offline

locum wrote:

Idesof wrote:'And I still can't get over that fuel load: 18,500lbs! ..... AND a large internal armament load. A miracle of engineering in my book.'
He he Idesof, first I thought the same, but I saw the X-35 parked side by side with a F-16, if the F-16 is a sleek Cheetah than the X-35/ F-35 is a Rhino or Hippo. The F-35 has a very volumeous fuselage, because of the F-35Bs' liftfan the fuselage needs to be wide: advantage= a lot of internal fuel, disadvantage= the aerodynamic qualities are decreased.

Many forget the F-35 has a thrust level somewhere between the F-14A and F-15C all the while being much lighter...........and will carry its weapons load interally. Talk about turn and burn! Twisted Evil

Elite Joined: Oct 21, 2005 Posts: 735 Status: Offline

Corsair1963 wrote:

and will carry its weapons load interally. Talk about turn and burn! Twisted Evil

Ahhh.....the wonders of internal weapons carriage.

Last edited by JCSVT on Jul 30, 2006 - 05:56 AM; edited 1 time in total

Corsair1963 wrote:

F-15C all the while being much lighter

I think that the F-35 will come somewhat close to the F-15C in terms of loaded weight. The F135 is very powerful and there is a reason for that. Not to say that it won't perform well but I have a feeling that it will be a pretty solid fighter. Most of this is due to the large fuel fraction and the progress of technology. It will have more range than an Eagle or Viper though.

F-35's weight is a fixed variable. It is not allowed to exceed its currently set target weight. All 3-classes are dependent upon weight limits set for the -B model.

Hence, tha A and C will be lighter than the B considerably since weight reduction measures applied to the -B will be applied to them as well.

Elite Joined: Dec 19, 2005 Posts: 615 Status: Offline

skrip00 wrote:

F-35's weight is a fixed variable. It is not allowed to exceed its currently set target weight. All 3-classes are dependent upon weight limits set for the -B model.

Hence, tha A and C will be lighter than the B considerably since weight reduction measures applied to the -B will be applied to them as well.

Also, we are just at the beginning of engine development. With the P&W F-135 making around 43,000lbs of thrust and rumors of the GE F-136 somewhere near 46,000lbs! Shocked

46,000?? Sounds like a rumour. Last I heard, 43,000 was a major development.

Elite Joined: Dec 19, 2005 Posts: 615 Status: Offline

skrip00 wrote:

46,000?? Sounds like a rumour. Last I heard, 43,000 was a major development.

While, I would have to concede that it is just a rumor at this point. I don't think its unreasonable. Especially, if the P&W F-135 is making 40,000-43,000lbs in its current form. As the GE F-136 is a more advance design. Further, earlier P&W F-100's for example made less than later GE F-110's. Which, inturned forced P&W to develope more powerful F-100's to compete.......Which, looks like history is going to repeat itself! Surely, a good thing for everyone envolved. Thank the Good Lord they kept funding (reduced) for the GE/RR F-136 engine! Very Happy

But then again P&W did make those awesome engines that power the F-22A, and they built upon that success to make the F135.

Forum: F-35 Lightning II

F-35 Range