Dienstag, 31. Juli 2012

Navalized Typhoon vs. F-35B

The following press release made me think about writing a short paper about the procurement of aircraft for future British aircraft carriers. Initially, I am going to show the current state of affairs. Then, I am going to argue the economics of such a decision. Finally, I am going to discuss the performance of the final product.

1. Current State of affairs

"UK slashes F-35B numbers but might look to split buy with F-35As"

This is the title of a recent article that inspired me to write a short review of the UK's decision to employ short take of and vertically landing (STOVL) aircraft for their new Queen Elizabeth aircraft carrier. Now, there is some wavering going on in the UK about the aircraft carrier and its aircraft. Originally, the F-35B was chosen. But, due to the F-35B's low weapons load and limited operating range, the F-35C was chosen instead. However, this version requires a short take of and arrested landing design. That is, the aircraft carrier must be equipped with a catapult and arresting wires. Finally it turned out that these modifications would be too costly. Therefore, the UK chose to order the F-35B and stick to the original carrier design, i.e. a sky jump for short take offs and vertical landing on the flight deck like harriers. But this hasn't been the last word in this matter:

"UK Defence Secretary Philip Hammond has signalled a major revision to the UK's plan for procuring the Lockheed Martin F-35 Joint Strike Fighter (JSF), with a sizeable cut in the expected number of F-35B short take-off/vertical landing (STOVL) aircraft purchased and the possible acquisition of a second variant: the conventional take-off and landing (CTOL) F-35A."

So they decided to cut the number of F-35B, that's for sure. The possibility of getting F-35A instead is next to nil given the current budget restraints. I presume that this was said in order to appease the US manufacturer.

"In remarks on 19 July in the United States, Hammond said the UK would order 48 F-35Bs to equip the UK's future carrier strike force."

This can only mean two things: Either the UK is planning to scrap the second new aircraft carrier or the UK is wiggling its way out of the F-35 acquisition. Why is that so? Each aircraft carrier is going to be equipped with around 40 aircraft. 48 F-35 are just not enough, around 80 to 100 aircraft are required.

"He added that a follow-on F-35 buy would be set out in a future Strategic Defence and Security Review (SDSR), with the aim of replacing the Eurofighter Typhoon in UK service."

But, the Typhoon has been in service for less than 10 years and is expected to stay in service for the next 30 to 40 years? Furthermore, the UK hasn't even received all of the typhoons it has ordered? In this circumstance, it seems far fetched to talk about a replacement for the typhoons? In my opinion, the defence secretary is again making non-committal statements in order to appease the disappointed Americans.

But, I wouldn't be surprised if no more than a single F-35 is actually going to be bought by the UK.

2. Economics

What would be the smartest thing to do from a pure economical point of view? I am assuming that the UK still wants to field two aircraft carriers! The Typhoon costs far less than the F-35B, i.e. 120 million € vs. between 150 to 200 million €  per plane. I am assuming that the navalized version of the typhoon is going to be roughly 20% more expensive than the standard typhoon. Finally, the addition of arrestor gear on the UK aircraft carriers is an old school technology. The UK could buy the technology from the French or Americans. Otherwise the flight deck of the aircraft carrier would remain the same.

The conclusion is: The navalized typhoon would be far more cost effective than getting the F-35B.

3. Performance

So now let's look at the performance of the two aircraft, F-35B and Eurofighter Typhoon. From the get go I'll grant that the F-35B has a lower radar cross section. However, it is not on par with the F-22's radar cross section. The F-35's radar cross section is only noticeably reduced from the front, like the Typhoon. The figures are classified, but these are probably quite accurate:

Radar cross section:

Typhoon: 0.05 m²
F-35:        0.001 m²

That is definitely a considerable advantage. But, these figures merely represent the radar cross section from the front of the aircraft. The radar cross section is considerably larger from the side or back of the plane. Additionally, these figures do not apply to long wave radar emissions, which may be used by ground forces.

Stealth is not the only important design factor of a fighter aircraft. Stealth is merely one important design parameter among dozens of other features, which must be optimized. The vast majority of successfull engagements in air-to-air combat have been won in visible range. The radar cross section is of no help in this domain. The agility of the aircraft is more important than its radar cross section; it is determined largely by the wing load and the thrust-to-weight ratio of the aircraft:

Thrust-to-weight-ratio:

Typhoon:
maximum: 1,60
nominal:    1,16
minimum:  0,76

These figures are achieved in the peacetime settings of the engines, which is optimized for engine endurance. Additional thrust can be generated in the wartime setting.According to Eurofighter GmbH, the additional weight of a navalized typhoon would be around 500 Kg. This penalty has been considered. I am assuming that the same engines are being used. 

F-35B:

maximum: 1,34
nominal:    0.9
minimum: 0.72

Maximum means using the empty weight of the aircraft as a reference. Nominal means with full fuel tanks but without weapons loaded. Minimum means with full fuel tank and maximum weapons load.

So, in terms of speed and acceleration, the Typhoon is far superior to the F-35B.

The next important performance characteristic is the wing load. It determines how much weight each square meter of wing has to carry. An airplane turns by applying lift using its wings. The smaller the wing load, the higher the turn rates of the aircraft.

Wing load:

Typhoon

Minimum: 230 Kg/m²
Nominal:   320 Kg/m²
Maximum: 480 Kg/m²

F-35B=

Minimum: 341 Kg/m²
Maximum: 637 kg/m²

An additional factor is the inherently unstable design of fighter aircraft. This means that the lift generated by the wings is going to turn the aircraft on its own unless air control surfaces such as canards stabilize the aircraft. A highly instable airframe even in the supersonic realm was a major design goal of the typhoon. The Typhoon is far more maneuverable than the F-35B. In any dogfight the F-35B would be eaten up by the Typhoon. This is also apparent from the G-limits of the aircraft; Typhoon (9G) - upper limit for pilot safety; the F-35B turn rate is abysmal and has been lowered even further:

"The US Department of Defense's decision to relax the sustained turn performance of all three variants of the F-35 was revealed earlier this month in the Pentagon's Director of Operational Test and Evaluation 2012 report. Turn performance for the US Air Force's F-35A was reduced from 5.3 sustained g's to 4.6 sustained g's. The F-35B had its sustained g's cut from five to 4.5 g's, while the US Navy variant had its turn performance truncated from 5.1 to five sustained g's. Acceleration times from Mach 0.8 to Mach 1.2 were extended by eight seconds, 16 seconds and 43 seconds for the A, B and C-models respectively. The baseline standard used for the comparison was a clean Lockheed F-16 Block 50 with two wingtip Raytheon AIM-120 AMRAAMs. "What an embarrassment, and there will be obvious tactical implications. Having a maximum sustained turn performance of less than 5g is the equivalent of an [McDonnell Douglas] F-4 or an [Northrop] F-5," another highly experienced fighter pilot says. "[It's] certainly not anywhere near the performance of most fourth and fifth-generation aircraft.""


Please also bear in mind that the navalized typhoon is going to have 3D thrust vectoring in order to reduce the minimum speed for landing. 3D thrust vectoring also improves the maneuverability of the aircraft at low speeds considerably. If the navalized typhoon is equipped with the newer engines E230, then the maximum thrust is going to be boosted by around 20%.

What do we know about the resulting agility of these airplanes. Hardly anything about the F-35B, because it is supposedly classified! How classified can this be, if the plane is sold all over the world? The real reason is the abysmal performance of the F-35B. Whenever you read classified you may safely assume that there is nothing to brag about.

Top Speed:

Typhoon: Mach 2.35
F-35B:     Mach 1.6

Super Cruise speed:

Typhoon: Mach 1.5
F-35B:      Imossible

Rate of climb:

Typhoon: 315 m/s
F-35B:     Classified

Another important aspect of the airframe is how much additional weight it may carry. This is called weapons load.

Weapons load:

Typhoon: 7500 Kg
F-35B:     6800 Kg (unstealthed)

However, the F-35B sacrifices all of it's stealth advantages, if it carries the weapons externally under the wing or fuselage. With internal weapon bays it can only carry two air-to-air missiles, each weighing around 160 Kg and two bombs or missiles, each weighing around 1100 Kg. So how much is that in stealth mode?

F-35B: 2500 Kg (stealth mode)

For a plane that does not have the performance to be an air superiority fighter, the most reasonable use is as a striker or bomber. However, the weapons load of the F-35B is bad in stealth mode and even unstealthed considerably lower than the Typhoon.

Finally, I want to discuss the combat radius of these airplanes.

Combat radius:

Typhoon: 1.389 km
F-35B:        833 km

These are all decisive figures, which cannot be improved upon without fundamentally redesigning the aircraft. These figures should be the prime concern when getting the airplane.

The sensors and effectors of the aircraft are all very important, but they are going to be upgraded in the course of its lifetime. Therefore, it doesn't make sense to acquire an aircraft on the basis of electronic gadgets, although they are extremely important for its success. You can equip any old F-16 with the newest electronics! No need to get a completely new design of the airplane.

Last but not least, the Typhoon can be equipped with world class avionics and missiles:

I. Sensors:

a) Radar: Captor-E: ASEA radar due 2015
b) Infrared: PIRATE: Passive Infra-Red Airborne Track Equipment
c) MAW: Missile Approach warner
d) MIDS: Multifunctional Information Distribution System
e) Sensor fusion

II. Defense: PRAETORIAN : Defensive Aids Sub-System comprising:

a) MAW: Missile Approach warner
b) ECM: Electronic Counter Measure (Jamming)
c) ESM: Electronic Support Measure
d) Laserwarner
e) Chaff Dispenser
f) Flare Dispenser
g) Towed Decoy

III. Air-to-air missiles:

a) long range radar guided: AIM-120, MBDA METEOR
b) short range infrared guided: AIM-9 sidewinder, AIM-132, IRIS-T

The missiles can receive their target designation after being launched using a wireless data link. The information is received from the sensors, inculding Radar, Infrared and MAW. The missile approach warner provides coverage in 360° around the aircraft. Consequently, missiles can be launched in any direction, even at enemy aircraft or missiles from behind the aircraft.

Air-to-ground missiles:

a) Cruise missiles: TAURUS KEPD 350, STORM SHADOW,
b) Anti armor:       BRIMSTONE
c) Anti-radiation:  ALARM, AGM-88
d) Close air support: AGM-65
e) Anti-Ship: Penguin (AGM-119)

Precision guided bombs:

Paveway II, III and IV, JDAM

Cockpit:

Carefree handling: No stalling or excess of G-limits.
HOTAS: Hands on Throttle and Stick
HMD: Helmet mounted display
HMSS: Helmet mounted symbology system
HUD: Heads up display

4. Conclusion:

The UK has no need for a stealthy bomber (F-35) with a very limited range that can only carry two bombs in stealth mode.

Bombing missions that require stealth, like air interdiction, should be to be carried out by stealthy cruise missiles such as storm shadow or Taurus KEPD. Stealthy bombing missions may be carried out by stealthy UAVs, like the US predator-C. Both the UAVs and cruise missiles are much smaller and much stealthier than any manned airplane could ever be. If you want to drop precision guided bombs from high altitudes, then aircraft such as the Tornado or Typhoon can easily do the job. A dedicated plane like the A-10 warthog should be acquired for the close air support mission.

Last but not least, advances in radar and infrared sensors are going to mitigate considerably any advantages of a stealth design in the near future. This will be done by fusing the sensors of many different aircraft, such as Typhoons, AWACS, ground radar and unmanned drones.

Kommentare:

  1. The 48 procurement is more than enough to equip the carriers. The two carriers will not ever operate simultaneously. The point of having two would be so that one could be in maintenance while the other is under operations. The UK has pretty much always deployed 12 fast jets routinely in peace-time. The typical war-time load of these carriers would be around twenty something F-35B and 5-10 helos depending on the missions.

    The price of developing a naval Typhoon, equipping the carrier with catapults (which would not be old technology, given that the carriers use gas turbine propulsion, the catapults would need to be the new electro-magnetic configuration), would be astronomical. Purchasing the F-35B is pretty much the only affordable option on the table right now, without the attempt to purchase some old second hand harriers.

    A naval Typhoon would require completely redesigning the plane, it is not as simple as slapping a tail hook on the end. The UK would have to independently redesign and strengthen the airframe and reconfigure the engines, materials and an endless list just to get those jets to last a week on a carrier.

    I like the idea of a naval Typhoon as much as you probably do, but it is not practical, affordable or ever going to be considered.

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  2. "The price of developing a naval Typhoon, equipping the carrier with catapults..."

    The navalized typhoon is supposed to take off from a ski ramp. No need for a catapult.

    The UK would not have to redesign the plane, the typhoon is a proven design and strengthening the landing gear as well as the tail hook is well within the UKs technological capabilites. A navalized typhoon was offered to India. If Spain and Italy, both operating aircraft carriers with harriers, would join the party, costs could be cut even more.

    The F-35 is still in development - although it is already in production. The costs for each airplane - especially the F-35b STOVL version - is astronomical and the capabilities are bad.

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  3. I don't think that it's cost effective to build a naval Typhoon but it would make a lot of sense to equip at least one of the Queen Elizabeth carriers with a cat and trap system so that the French Rafale M's could operate from it as well as the F-35 B. Rafales have exercised on US carriers with cat and trap. It would be nice if the French could fly from a QE carrier when the Charles de Gaulle is in maintenance and vice versa.

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    1. " but it would make a lot of sense to equip at least one of the Queen Elizabeth carriers with a cat and trap system so that the French Rafale M's could operate from it as well as the F-35 B."

      It's nice but not necessary. Your priority should be an aircraft carrier with a good fleet of aircraft. The F-35B is a piece of shit. It is by far the most expensive version of the F-35, which has the least capabilities and the greatest problems. If you want an aircraft carrier with "catapults and trap system", then get the French Rafale. If you want an aircraft carrier with the best possible aircraft, then get a navalized typhoon and build a ramp.

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