Forum: F-35 Lightning II

I do humbly apologize for missing the F-4 and it's J79...

It was on my list but I forgot to type it into the posting.

As for the RA-5 and B-58, they weren't USAF Supersonic Fighters, or current heavies, so that is why I didn't list them.

The J79 was truly a break-through motor of the time, a historical aircraft engine to be sure.
TEG

I do humbly apologize for missing the F-4 and it's J79...

It was on my list but I forgot to type it into the posting.

As for the RA-5 and B-58, they weren't USAF Supersonic Fighters, or current heavies, so that is why I didn't list them.

The J79 was truly a break-through motor of the time, a historical aircraft engine to be sure.

I don't want people to get me wrong here. GE makes a great product, as does PW. They both make excellent fighter and commercial engines.

I just deal with the whole GE/PW USAF Viper issues on a daily basis. (Deployments, tooling, parts, training, etc). It's poor planning, militarily speaking, to purchase identical weapon-systems with different engines. I also believe the billions given to GE for an alternative F-35 engine, could be better spent investing in the chosen power.

As for the "partner" status of the JSF/F-35 program, how about the KC-45? If Poland ever wanted to purchase a few KC-45s, and wanted PW engines on them since they have a PW assembly facility, would the US DoD foot the bill for all the development and testing?

Isn't this why some countries want GE engines available for their F-35 purchase? What percentage of F-35 w/GE compared to the Billions that could be saved for purchase of additional airframes for the USAF?

Keep 'em flyin'
TEG

The F-100/F-110 is a totally different animal than the F-135/F-136. Which, unlike the former will be completely interchangable.........

I read somewhere that the J79 has more hours at supersonic speeds than any other motor. Partially due to the sheer number of motors and partially due to things like the B-58.

"Completely interchangeable" unless you consider parts, training, technical-data, tooling, overhaul facilities, operating limits, contracts, suppliers, etc...

The fuel-pump from an F135 won't fit an F136, mechanics certified on F136 won't be "allowed" to work F135, two sets of "books", two overhaul lines...

They may be "plug-and-play" in the airframe, and feel/sound the same to the pilot, but I highly doubt they will be truly interchangeable at all levels. If the USAF is forced to buy BOTH engines, they will be in the same situation as the F100/F110 when it comes to $$ and deployments.

No. The Olympus 593 in the Concorde has the most supersonic hours of any jet engine.

On 2 March 1999, the 30th anniversary of Concorde flying, an average fleet total of 10 aircraft had flown 920,000 hours. This total included considerably more than 600,000 hours at supersonic speeds, easily exceeding the total supersonic time of all other aircraft in the Western world.

600,000 * 4 = 2,400,000 Hours above Mach 1

The Olympus 593 in the Concorde has the most supersonic hours of any jet engine.

2,400,000 Hours above Mach 1

Agreed...........That said, my point had more to do with being interchangeable on the assembly line. I hardly see the advantage of the USAF for example ordering both types. The P & W F-135 for the USAF F-35A and possibly the GE F-136 for the USN F-35C mite be a different story?

ahh the Olympus.... The only afterburning turbojet to power a commercial airliner!

An engine guy's dream flight!



But then the US DoD is still paying for 2 different logistics systems for the F-35 program. USAF would have an overhaul depot or OEM contract for the F135 and the USMC would have another depot or OEM contract for the F136.

The F-35A/B/C are suppose to share between 70 and 90 percent of their parts. All in order to reduce total ownership costs for all involved. If you consider the engine 25% of THAT percentage (Engines are typically 25% of the total cost of an aircraft) then you're reducing the "commonality" factor to between 45 and 65 percent. Since the B is so much different than the A/C models, I would say it would be less than half common with the F136 versus and F135.

BTW Corsair

Engine designations don't use a "dash" behind the initial type designator. J79, F100, F135, F117 etc.

The "dashes" are used in the series, such as J79-GE-17, F100-PW-229, F135-PW-600, or F117-PW-100.

Andreas Parsch has a great site "Designations Of U.S. Military Aero Engines" that has it all.
http://www.designation-systems.net/usmilav/engines.html

You're saying the average number of flight hours for each Concorde was 92,000 hours?

Yeah, I thought you were smoking something.

http://en.wikipedia.org/wiki/Concorde

TOTAL fleet hours of every airframe ever built at any speed was: 243845. So you're only off by about a factor of four. Looks like you were mistaking engine hours for airframe hours.

The entire argument that the F135 and F136 are not interchangeable on the service level is basically a bureaucratic load of crock. It is like saying that Mechanics can either be Toyota Mechanics or BMW mechanics but not both because the engines and transmissions on the cars built by these two manufacturers are considerably different inside and out. The fact of the matter is that you can make a Mechanic certified to work on both fighter engines just like you can certify mechanics to work on a range of different cars.

I'm not saying you CAN'T, but it is exceedingly difficult for a large number of people and aircraft at a large base that is constantly deploying in the AEF world of today.

The current USAF rules that govern certification for blade blade, intake inspection, borescope inspection, low-power engine operation, high-power engine operation, among others make it a training nightmare. Not only is there initial training on multiple types, but then recurring training that must be re-accomplished anywhere from 60days to yearly, and recertification on specific tasks annually. Miss your 60 day "refresher" or "currency" and you get de-certified and have to start over with a fresh initial or recert. (I'm not making this stuff up... am I guys?)

Even F-16 PW-220 and PW-229 engine training must be certified separately due to the differences in the TMSM. IE if you're trained/certified to perform borescope inspection on a PW-220, you can not sign-off a borescope inspection on a PW-229. If one did, and misses something that is found later or contributes to a mishap, and everyone involved gets caught in the ringer.

When you go to an AEF deployment, engine mechanics from a GE Block 40 unit with can not perform specific technical tasks on a PW Block 42 unit's aircraft or vise versa. One can "assist" or perform other tasks, but important inspections and operation is restricted. When you call in a maintenance run to the control center, they will check your name/number against the special certification roster for that task. If you're not certified or not current for the procedure, your run will be denied. Start the jet and security will be there shortly...

I'm not saying the USAF (USN or USMC) couldn't or wouldn't change the rules. I also know on a smaller scale operation like Edwards, or Eglin's Test Wings, there are technicians that perform maintenance on multiple engine/aircraft types.

Point is, this all adds expense and complexity within a single branch. Two training tracks at technical school, two sets of technical data, two this, two that... Like units can only deploy with other like units etc... Mobility listings must be aligned by engine types.

True the Viper's "common engine bay" is nothing but a ruse. Engine mounts are different, connections are different, even the engine removal/installation trailer has different equipment. This is a prime example how to not design an "alternate engine" for an airframe.

True the F-35 team is dedicated to make the engines "installationaly interchangeable" Beyond that though, they are still PW and GE with separate specifications, technical data, parts, training, contracts, etc.

It is false to say the true facts don't/won't add expense to a program, either for development or sustainment. Or that it doesn't over-complicate military operations when one branch has similar aircraft with different engines.