Thrust to weight Ratios and the f-35

a reply to: true4man

Currently it puts out 40,000. The final version of the engine will put out 43,000. The F-18 has a slightly better T/W, but the F-35 has better performance, due to the weapons bay.

originally posted by: Zaphod58
a reply to: true4man

Currently it puts out 40,000. The final version of the engine will put out 43,000. The F-18 has a slightly better T/W, but the F-35 has better performance, due to the weapons bay.

What about an Advanced Hornet with the proposed weapons pod? Much cleaner in terms of aerodynamics

a reply to: FredT

It'll be awhile before we get any kind of numbers, but that would be better than the regular Hornets, and closer to the F-35. But that's if they go with the original version. Last year they talked about a downgraded version of the ASH that didn't include the weapons bays, but incorporated some of the other improvements.

Zaph with your opinion what will make the difference between a F-35 A and a futur enhanced F-35 ? different engine ? more weapon ? long range ? better kinematic performance ? may be a Platform a little bigger to carry more fuel ?

a reply to: darksidius

Stretch the fuselage some. That gives you a larger bay and fuel load. Right now, it's barely larger than an F-16. It needs to be between an F-16 and -22.

a reply to: Zaphod58
All right and a futur AETP engine for better range and kinematic , sure I agree this time it will be an interesting F-35 + , put on it a laser weapon pod will be a good idea too.

a reply to: true4man

F-35 is able to put out 40,000 lb of thrust. F-18E is able to put out 44,000 lb of thrust. I think both weigh about the same no? This would make F-18E having better thrust to weight ratio compared to F-35.

F/A-18 E/F weighs 32,081 lb and has 44,000 lb thrust. This gives it maximum t/w ratio of 1.37.

F-35A (Air Force) weighs 29,098 lb and has 43,000 lb thrust. This gives it maximum t/w ratio of 1.48.

F-35C (Navy) weighs 34,800 lb and has 43,000 lb thrust. This gives it maximum t/w ratio of 1.24.

originally posted by: SmilingROB
Hi
I have been having fun recently calculating thrust to weight ratio on various jet. Most need to use burners to do pure vertical climbs which is fair.

When I play with the number the F-35 does not appear to able to do sustain vertical climbs. I appreciated that it very manuverable and can do m 1,6 but.....

Or is it aerodynamically efficient enough that it does it regardless Or does it Have more than 40,000 lbs of thrust?

Thank for the input

Hi, some slightly late numbers.


a/c min.load max. load mach wing size
DRY BURNER DRY BURNER

F-15e .6557 1.0683 .4291 .6991 1.2-2.25 608

Su-35 .6847 1.1260 .5101 .8388 1.5-2.25 667

F-22 .8019 1.079 .6227 .8383 1.82-2.25 840

F-23 1.0132 1.3639 .838 1.129 2.2 900

F-5e .4445 .6351 .2831 .4044 1.6 ? 186

F-16 .6598 1.079 .4055 .6761 1.2-2 300
ARMOUR CAS MAX.
A-10 .5966 .4309 .3849 .3826

@ 28,000 DRY BURNER @43,000 lbs
F-35 .5651 .8679 .4 .61 1.6 460

HI Gang

Here is a collection of known a/c with their t/w ratio calculated. I know may of actually work with these a/c, my nimbers are mostly from wiki, please point any minor differences.

One person joked about the f-35 at it's empty weight, here are the numbers: dry .96 , burner 1.4777. You wouldn't get far with zero gas and oil but what the hell they are just numbers.

From a power stand point the 35 seems to fit nicely between the f-16 and the A-10. On f-16.net they talk about the nimbleness of the f-35. Making it a worthy playmate for the f-22.

The simple math says the -35 cannot do long strong vertical climbs. The sleek design should help it maintain/regain speed I know it's supposed to be a BVR a/c but will it perform vertical scissors (etc.) if required.

The F5 used to be considered a nimble jet and fight worthy jet with number of .4445 so I have hopes of hearing positive things.

a reply to: C0bzz

those are the empty weights

no gas ='s no flying

The simple math says the -35 cannot do long strong vertical climbs. The sleek design should help it maintain/regain speed I know it's supposed to be a BVR a/c but will it perform vertical scissors (etc.) if required.

Maybe have to look at the drag coefficiency..

According my calculation F-35 has a bit better TWR than F-18E.

F-35 40,000 lb thrust, empty weight 29,098 lb.

F-18E 44,000 lb thrust, empty weight 32,081 lb.

en.wikipedia.org...

en.wikipedia.org...

a reply to: 2partySystem

The F-18E is 0.93/1.1 compared to 0.87/1.07. The F-35 will improve when they update the engine and reach full thrust though.

a reply to: SmilingROB

I am aware and I did this deliberately.

Every aircraft is typically designed for a different mission, therefore they will have a different internal fuel capacity and payload. The quoted loaded weight will always have a different payload between aircraft. This means that when comparing thrust-to-weight ratios, the results can be misleading because it's an apples to oranges comparison. Perhaps this can be useful, if for example you were attempting to compare how a heavily laden strike fighter with a payload of A2G munitions would fare against a clean point-defense fighter, or other specific situations.

For an apples-to-apples comparison, then all aircraft should have a similar loadout or it should be specifically mentioned that each aircraft in the comparison has a wildly different payload. Alternatively, you can start with the empty weight, which in my opinion should be the starting point for such comparisons, then simply state what can be added to each aircraft.

As it stands:
- The F-35A is a 29,098 lb aircraft with an internal fuel capacity of 18,498 lb. 43,000 lb of thrust. Maximum takeoff weight: 70,000 lb.
- The F/A-18 E/F is a 32,081 lb aircraft with an internal fuel capacity of 13,550 lb or 14,400 lb. 44,000 lb of thrust. Maximum takeoff weight: 66,000 lb.
- The F/A-18C is a 23,000 lb aircraft with an internal fuel capacity of 10,860 lb. 35,500 lb of thrust. Maximum takeoff weight of 51,900 lb.
- The F-16C is a 18,900 lb aircraft with an internal fuel capacity of 7,000 lb. ~29,000 lb of thrust. Maximum takeoff weight: 42,300 lb.
- The F-15E is a 31,700 lb aircraft with an internal fuel capacity of 23,280 lb (including conformal fuel tanks). ~58,000 lb of thrust. Maximum takeoff weight: 81,000 lb.
Note 1: Those are empty weights unless otherwise stated.
Note 2: Figures obtained via Wikipedia, or high placing Google searches.

Generally I would place overall energy maneuverability in the following order for a strike mission: F-15E > F-35A > F/A-18 E/F > F/A-18 A/B/C/D > F-16C. The above specifications should make it obvious why.

The design point of the F-35A is usually internal fuel only, with 2x 2000 lb munitions and two AMRAAM. If you take the payload and range of the F-35A in this condition and try to apply it to the F/A-18 (any version), F-16 (any version), Gripen (any version), then they will have external stores, additional external fuel tanks, and external sensors. These add weight and drag, hell even the pylons without anything on them add weight and drag. On the Super Hornet the pylons are toed outward by several degrees, which increases drag. The F-35A will outperform them very significantly.

On the other hand, a F-15E will likely significantly exceed the F-35A. As will the Eurofighter, maybe Rafale, and definitely the F-22 (2,000 lb munitions excluded), at the design payload & range of the F-35A. A F-35A will also be handily outperformed by a F-16A at the original design point of the F-16A (short range air-to-air fighter). The 4th generation fighters also can drop external stores to become cleaner.

So I think we either need to accept that t/w ratio figures are often an apples-to-oranges comparison. Or compare the aircraft with matching payloads for a specific mission or range of missions.

On another note: F-35C in my opinion is a bit of a dog though...

a reply to: C0bzz

I take your point to degree.

If weight wasn't important to an aircraft they would not spend so much time calculating it, balancing it, etc.

I am not aerodynamics engineer I am the guy in the basement.

It seems pointless to compare how the aircraft could fly if it was not carrying gas because it cannot fly without carrying gas.

The engines dry thrust is 28,000. It's unclear if the ,to me, if the f-35's after burner has zones or is bang all the way on?

My original question was can the f-35 low drag enough with its minimum load, burner on t/d ratio of .8679 to perform long sustained vertical climbs. The math says no I wanna know what real life says.

a reply to: SmilingROB

All afterburners have zones, from min to max. The SR-71 used to refuel with one at min to keep the aircraft flyable.

F-22 has super cruise. I would have thought F-35 has super cruise. It apparently does not.

a reply to: Zaphod58

Cool. Good to know.

Thank you.

a reply to: SmilingROB

You have military power, which is 100% thrust short of afterburner. Then you have "minimum augmentation" which is just over the "gate", "mid augmentation" which is past the gate but short of the throttle stop, and "maximum augmentation", which is all the way to the stop. With each step more fuel is sprayed into the exhaust, which provides more thrust.

a reply to: FredT

If they could have stretched the Hornet's design, they would have done it with the E/F models. I think that it has about reached it's potential. The upgraded engines will improve it some, but not enough in my opinion.