|Artist's rendering of F-35Bs operating from HMS Queen Elizabeth.|
Remember that F-35B flyby hoped for the HMS Queen Elizabeth's naming ceremony? It is not going to happen. You can thank the JSF's recent history of spontaneous combustion, combined with a 36-hour turnaround time for that. Appearances at the Royal International Air Tattoo and Farnborough Air Show are still scheduled. First, the F-35Bs will have to contend with a mandatory inspection before being given U.K. flight clearance. There is also the matter of tropical storm Arthur possibly mucking things up as well.
With all the anxiety and hand-wringing involved in the JSF's upcoming transatlantic trip, I thought it would be a good time to examine the F-35's range.
In an aircraft, running out of fuel is more than an inconvenience. Without fuel, even the most advanced jet fighter becomes a simple glider... And then possibly a crater.
Thankfully, there are plenty of ways to extend an aircraft's fuel capacity and range.
|P-51D Mustang drop tank|
External fuel tanks can add a great deal of range to a multirole fighter. This enables it to increase its combat radius or prolong its loiter time. The extra fuel can also help offset the extra juice needed to carry a large bomb load. Less glamorously, sometimes extra fuel is needed simply increase the aircraft's ferry range, enabling it to reach a far away station without the need for refueling.
All this extra range comes at a price. External fuel tanks add a great deal of weight and drag to an aircraft, decreasing the aircraft's performance while increasing that aircraft's fuel demands. They also take up room on an aircraft's weapons pylons, reducing the amount of missile and bombs able to be carried. Some external tanks cannot even go supersonic.
|CF-18 with three external tanks.|
The F/A-18, of which the CF-18 is a variant, was never meant to be a long range fighter. In its natural habitat, the USN, the Hornet was a light "jack of all trades" serving alongside two more specialized designs. Long range interception duties were meant to be handled by the USN's F-14 Tomcat, and Long range strike missions were carried out by the A-6 Prowler.
Thankfully, all of the potential CF-18 replacements have substantially superior ranges to the Hornet. No matter which aircraft Canada eventually selects, it is certain that it will fly further than our current fleet without external tanks.
But what if we need to fly further?
For that, external tanks are still an option for all the jets... With one exception.
All models of the F-35 have a large space just aft of the cockpit. For the STOVL F-35B, this space is reserved for the lift-fan. With no need for a lift-fan, the CTOL F-35A and CATOBAR F-35C are able to utilize this space for fuel. As you can see in the illustration above, this accounts for over 4,000lb of extra fuel for the F-35A compared to the F-35B. Because of this, literature for the F-35A often touts the fact that the JSF can match the range of legacy fighters like the F-16 and F/A-18 even when the latter have external tanks.
If a clean F-35A can match the range of a tanked up CF-18, then a F-35A with external tanks must be able to go substantially further, right?
Early F-35 information portrayed the JSF as capable of carrying up to two bowling pin shaped 426-gallon wing tanks. The F-35's inboard wing pylons are "wet", so it only makes sense that external fuel tanks would be available. The odd shape was adopted as traditional spindle shaped tanks were found to have "separation issues" (i.e. crashed into the plane when jettisoned).
Wind tunnel testing revealed that changing shape of the tanks did not fix the problem completely however.
As of now, there are no definite plans to add external fuel tanks to the F-35. There are rumors that Israel may choose to design and build some, but no F-35 customer currently requires them (i.e. nobody wants to pay for their development).
Where the JSF is currently suffering from a lack of external fuel options, the other fighter aircraft available may soon have a wealth of options.
|F/A-18 Super Hornet|
While the Gripen NG has not seen any CFTs yet, they will be possibly looked at in the future. There is not really a rush however; changes made to the Gripen NG's fuselage and wing enable a 40% greater fuel capacity than the legacy Gripen models. Saab is also working on larger, 450 gallon tanks to extend the Gripen's range even further. These developments squash one of the Gripen's main criticisms, its lack of range.
|F-15E with unmounted CFTs, formerly known as "FAST packs".|
It could be argued that an aircraft's maximum range with external tanks is not relevant when aerial refueling is available. In a perfect world, maybe, but aerial refueling brings its own challenges and limitations. Not the least of which is: What type?
|F-35A refueling via a "flying boom" method.|
- "Canadianize" the F-35A to utilize probe-and-drogue.
- Purchase either the F-35B or F-35C instead (both use probe-and-drogue).
- Make do without a sovereign aerial refueling capability until time comes for a CC-150 replacement.
Unfortunately, each and every one of these options would add both cost and complexity to a fighter program already notoriously over budget and behind schedule.
- A "Canadianized" F-35A (CF-35CA?) would require additional cost and testing. It would also reduce the commonality benefits a CF-35 would have with the rest of the global F-35 fleet.
- Both the F-35B and F-35C are significantly more expensive than the F-35A. They also have reduced performance due to higher weight.
- Likely the most attractive option, Canada can rely on USAF tanker assets or private firms to provide aerial refueling. When the time comes, we simply replace our current CC-150 fleet with a tanker capable of supporting boom-style refueling. This would likely be either the Boeing KC-46 Pegasus or Airbus A330 MRTT.
|Airbus A330 MRTT (notice the flying boom and the drogues)|
Then again, purchasing new aerial tankers could be problematic given Canada's recent defense procurement history. The KC-46 has a unit cost of almost $300 million, and its selection by the USAF over the A330 MRTT was controversial.
The question that needs to be asked is fairly simple: How badly does Canada need a "boom" style tanker?
|CC-150 refueling pod.|
There is an interesting proposal, found here, to incorporate Bombardier's new C-Series passenger jet as the basis for a new MRTT (multi-role tanker transport) as well as the basis for a CP-140 Aurora replacement. This proposal could be extremely promising, not to mention politically rewarding.
|CC-137 and CF-18|
|CC-130H(T) ready to refuel CF-18s.|
So with all the flexibility and simplicity of probe-and-drogue refueling, why do aircraft manufacturers bother with the flying boom system?
|B-52 Stratofortress refuels|
Would the addition of a boom-style aerial tanker really help the RCAF? It would, but the difference would be negligible. While both the CC-17 and CC-130 are compatible, both are already long-range aircraft (5,000kms for the CC-130J, up to 10,000km for the C-17) making in-flight refueling of little use for most flights. The the CC-17 also makes up a rather small fleet of only 4.
By contrast, fighter aircraft would likely be the biggest users of aerial refueling. With shorter ranges along with the need to deploy just about anywhere in the world as part of a coalition, the ability to carry lots of fuel and be refueled is imperative.
In a country as big as Canada, with a NATO commitment that sees the majority of our fighter deployments overseas, range is not just a luxury for Canada's next fighter, it is a necessity. A combat aircraft is of little use if it cannot get to where it needs to be.
With no current provisions for external tanks and an incompatibility with Canada's aerial tankers, one has to wonder if the F-35 is up for the task.