The Fighter Engine Debate: Is More Better?

11/09/2021
By Billie Flynn

If there is one recurring theme when talking fighters in Canada, it is that fighters need 2 engines for flying over the Arctic.  Unique to a Canadian audience, opined by people from all walks of life, the issue is set deep in the psyche of so many.

Forget facts about how infrequent the RCAF flies in the arctic, forget advancements in engine technology that negate the need for a second engine as redundancy and forget the historical threats to pilot safety, the 2-engine mindset is here to stay.

Great marketing by Boeing and other adversaries early in the new fighter competitions cemented this theme and left it towering over any other comparison between 4th  and 5th Gen fighters.

Remember:  Perception is Reality

In my many years associated with F-35 in Canada, I have yet to see the best communications efforts move the needle off that theme.

So how do we change people’s minds?

Facts, historical references, and linking the RCAF use to other Western nations and their view on 1 vs 2 engine fighters are needed.  At some point, truth wins.

Aircraft designers determine if one or two engines is needed based on performance, not redundancy.

Aircraft manufacturers need power to achieve the performance specifications of the fighter jet, whether that be speed, maneuverability, or both.  Size and space for engine(s) are a consideration, sometimes the design would be too cramped to fit two engines when one would do.  Older generation fighter engines where not powerful enough to push a fighter to the speeds required so the designers needed two engines vice one.  In today’s 5th Gen and soon to be 6th Gen engines, unleashing 40,000 lbs. of thrust is enough to push a fighter to the supersonic speeds required plus maneuver aggressively.

These engines are twice as powerful as a 4th  Gen engine in a Super Hornet or Gripen.  Note that never…. I mean never…has 1 versus 2 engines been a safety or redundancy design consideration.  “Joe 6-Pack” on the street may say so but the very smart designers and engineers did not build a fighter with 2 engines for redundancy.  It’s all about power.

We now have a fighter engine as reliable as commercial engines.

In the past, 4 engine airliners crossed the Atlantic and Pacific oceans, down to Australia or across any major body of water.  Not until 2 engine-airliners were designed with ETOPS (Extended-range Twin-engine Operational Performance Standards) capability did the 4-engine versions fade away.  Today we fly around the world with the utmost of confidence that the 2 engines will get us safely to our destinations.  No one refuses a trip on a 2-engine Boeing 787 to instead book a flight on a 4-engine Boeing 747…. you might avoid flying on a 737 Max but that is a different story.  The robustness and reliability that is found in airliner engines has migrated to the design of 5th Gen fighter engines.

No longer are the fighter engines fragile and as unreliable as they were in the CF-104 and CF-101 days.  Even the GE F-404 and GE F-414 that power the legacy CF-18 and Super Hornet respectively do not measure up to the highly sophisticated and robust Pratt and Whitney F-119 (in the F-22 Raptor) or the F-135 engine in the F-35.  The maturity of the F-119 in the F-22 brought confidence that its newer cousin, the F-135, would be safe to operate in the F-35.  5th Generation fighter engines incorporate dual and triple redundancy and back-up systems for all major components and functions.

The rationale is that the engine must keep running to get the pilot safely home so a back-up to a back-up is incorporated throughout the design.  Nearly 500,000 flight hours in the F-35 fleet with remarkably stable engine statistics shows confidence that this engine design is robust.  The F-135 is 10 times more reliable and 13 times safer that 4th Gen engines which means reliability and robustness never known before in a fighter engine.

Does anyone drive a 1970s-era car and expect to get the fuel efficiency of a 2021 new vehicle?

More engines on a plane cost more to operate in fuel fees, more to sustain, repair and maintain and yet don’t push an airplane faster or more efficiently.  In this new era of emission considerations, more engines are not better or less costly.  This applies to 4 vs 2 engine airliners and 2 vs 1 engine fighters.  This is especially true when considering the F-414, a descendant of the F-404 in the CF-18, that powers the Super Hornet and Gripen.  Improved to the best it can be, this era of engines is not as fuel efficient as a 5th Gen fighter engine, meaning it will cost more per flight hour.

Over the lifetime of a fighter, 40+ years, the tally of extra spare parts and excessive fuel costs becomes an enormous sum.  $ millions are calculated and projected to understand the scope of this difference. Why would a nation buy a fighter with engines that will cost more to operate with older technology?

Canadians are not unique operating fighters from austere locations, they just think they are.

The fear of the super cold in austere locations gets everyone’s attention.  It is hard enough to start a car or truck in -40 degrees, a fighter must be infinitely harder to operate when it is super cold.  To prove that this myth did not exist for F-35, we tested the F-35 in the most extremes of temperature from +50 degree C down to -40 degree C in the McKinley Climatic Chamber, located in Florida.  The airplane was cold soaked down to those extremes, then operated as if it was on the ramp for start, taking off in full afterburner, and flying at those extremes through an entire flight cycle.

I admit being the first to be surprised at how well the F-35 performed under the harshest of conditions.  Once proven in ground tests, the F-35 was tested at Eielson Air Force Base near Fairbanks, Alaska.  Most recently, the beginnings of a full complement of what will be 54 permanently based F-35s at Eielson which will operate in those harsh winters, with just one engine.  All the while, the F-35 has shows that it is robust and tough enough to manage the harsh winter temperatures.

Blue Water Ops and Other Nations – The US Navy and US Marine Corps are buying 680 F-35B and F-35Cs and will operate from Marine Corps amphibious ships and Navy big deck aircraft carriers where there is often no alternate landing site except to return to the ship that it took off from…the term is Blue Water Ops.  If the reliability of single engine F-35 was an issue, would the most powerful force in the world risk their fleets?

Many other nations operate in austere conditions, from Norway flying over the north Atlantic and their far north, Denmark and the Netherlands conducting virtually all their flying over the North Sea, Australia flying off the largest coastline in the world, Japan far out over the Pacific Ocean, and so on.  Canadians don’t have the perspective to understand that the RCAF is not all that unique in how and where it operates.

Since 1992, the USAF has flown single engine F-16s from Eielson Air Force Base near Fairbanks, Alaska without a single engine failure over that 29-year period.

The USAF has based 4th Gen F-16 fighters at Eielson AFB for 29 years.  Never, in all that time has an F-16 been lost due to an engine malfunction.  Fairbanks is west of Inuvik where the CF-18s deploy for northern Arctic ops (on the west side) and further north than Iqaluit where CF-18s deploy (on the east side).  USAF F-16s fly 12 months of the year from Eielson AFB, whereas CF-18s deploy only occasionally for weeks at a time and usually within a 5-month window outside of the deep of winter.

How can Canadians argue for 2 engines in a fighter when the USAF has shown 3 decades of engine-free mishaps in a climate far harsher than Cold Lake, Alberta or Bagotville, Quebec?  The answer is that most Canadians don’t know about the Alaska F-16 story.

Canadian Fighters’ Bird Problem – Cold War fighter tactics dictated flying low level to and from our targets to stay below enemy ground defenses and reduce the risk of being shot down by anti-aircraft fire or surface-to-air missiles.  This tactical mindset drove flying training missions down, close to the ground, exactly where all sorts of birds fly. The bird strike risk was always present even though in later years, we became better at calculating when more birds would be fly (or migrating).

We would tailor the flying periods and locations for low level training to avoid the high migration areas.  Some birds ‘did not get the memo’ but we felt better, convincing ourselves that we had mitigated the risk.  Bird strikes happened often and in the era of the single engine CF-104, a bird strike could easily ruin that motor and lead to a crash.

In the CF-18 era, with 2 engines, a bird ingested in one motor often forced the pilot to shut it down and fly home on the remaining good engine.  It is interesting to note that more than 100 times, the F-35 engine has ingested large birds, metal pieces and other debris and operated flawlessly, as if the foreign objects were not there.

Canadian fighter low level tactics ended in the 1990’s when the western air forces learned that it was more effective and safer to ingress into enemy territory at medium to high altitudes (20,000 feet and higher) and protect the fighters and bombers with specialized aircraft to neutralize enemy defenses by electronic jamming or attacking with missiles and bombs.  Opening corridors or highways for the friendly aircraft allows them to enter and attack their targets and egress safely.  Oh, and there is stealth that permits those fighters / bombers to fly undetected in and out of enemy territory.  While low level flying is super fun and Canadians were especially good at it, the risk of hitting the ground was always present and the birds always a threat. 30 years of tactics evolution has taken away the need to train down close to the ground and keeps the fighters like F-35 away from the big-ass birds.

A direct comparison of the engine-related accident rates for the Pratt and Whiney powered 2 engine F-15 and single engine F-16 over a 25-year period are almost identical.

In the USAF fleets, a 4th Gen engine accident comparison of 1 vs 2 engines for the Pratt and Whitney powered 2-engine F-15 and single-engine F-16 over a 25-year period are almost identical.  How can that be?  It turns out that an engine failure on a 2-engine fighter often migrates to burn or damage that second engine and both fail.

Hence you didn’t buy better safety and redundancy with that second engine.

Canada would but a fighter powered by 1970’s engine design and operate them for 40 more years; those engines would have 90-year-old technology at the end of their lifetime.

Last generation fighters debated 1 vs 2 aircrew and whether the workload would be too much for a single human.  We have over the past 40 years proven that 1 pilot can manage the workload and the tradeoff of a rear cockpit with a systems operator was not worth it for virtually all mission sets.  Now we debate 1 vs 2 engines; and in this case, if 1970’s era engine technology for the CF-18 (and F/A-18 E/F) is what Canada should invest in to power the next fighter for 40 years to come.  Do the math…that means at the end of their lifetime, the engines powering Canada’s fighters would be based on 90-year-old technology.  Is there anything that we operate in our homes that is 40 years old now?  I cannot imagine extending the lifeline of technologies that have already been surpassed by 5th Gen engines and soon a newer generation engine that will power 6th Gen Next Generation Air Dominance fighters.  We will all be going to space in the coming years but Canada risks stepping back in time to invest in engine technology that is already a generation old.

Marketing the Arctic Goose

One of the best disruptors in the never ending and painful fighter replacement saga in Canada has been fronted by the competitors.  Since before the JSF / Canada partnership was announced and the competitors got wind of it, they have been pushing the need for 2 engines in the arctic.  What happens if a pilot sucks in a bird down the engine and must eject in the arctic?  He/she will certainly freeze and die, likely never to be found.  Before Lockheed Martin or the rest of the F-35 team could react, they were battling public distrust.

Yes, there are birds in the arctic, especially in migration seasons, often close to the airports when fighters would take off and land. They have always been a hazard but none of those birds are flying at 30,000 feet where the F-35s are operating.

And until Canada decides to permanently base fighters in the arctic, flying 12 months of the year up north will not occur.  RCAF missions will continue to have regular but infrequent deployments and training up to Inuvik and Iqaluit.  Bird risks on those takeoffs and landings will be the only exposure to any kind of birds.

So, God bless the marketing folks for their consistent messaging and shame on the RCAF and Lockheed Martin for not squashing that story a long time ago. If I worked for the competitors, I would never let that argument go.  As soon as politicians and media and the public look past the single engine myths, they will see a Super Hornet that first flew in 1995 but based on a design (YF-17) that flew in 1974 and realize that investing in 40+ year old technology to protect Canada’s arctic territory and coastlines for the next 40+ years would not be wise.

So, what do we know?

Single engines are as redundant and reliable as two engine versions. Single engines are more powerful and efficient than the 4th Gen engines powering the competitors of F-35.  The arctic is not lined with birds up to 30,000 ft and they won’t stop the F-35 engine and force the pilot to eject.

And the single engine costs less to operate and maintain over its lifetime saving $ millions.  Money matters these days, and it is hard to justify sustaining a fleet of motors that cost more to keep running and are less efficient.  Finally buying a fighter with 1970’s engine technology means operating Canada’s fighters powered by 90-year-old engine tech at the end of their lifetime.

Finally, let’s get past talking about 1 versus 2 engines in Canada and focus on the technologies that will keep the RCAF pilots alive so that they can come home safely each time.

The featured photo is of an F-35B flying at the MCAS Beaufort Air Show in April 2019 and is credited to Second Line of Defense.

This article was published by Billie Flynn on September 8, 2021.

Note from the author:

There was a great article published in the Globe and Mail about engine technology on June 1, 2021.