Forum: General F-35 Forum

TEG, what about flameout possibilities due disrupted airflow for whatever reason (spin?) or some other temporary cause (fuel starvation due prolonged inverted flight?)? Pilots will need to know what is possible in any given situation and for sure at what height to stop relight attempts and 'get out and walk'. Very Happy

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Flameouts will generally correct themselves and the engine will relight itself. That or there wasn't an actual flameout and all the pilot got was a caution. Very rarely an engine will fully "die" and stop producing thrust, if it came down to that you have bigger issues than bad air.

spazsinbad wrote:

'bager1968' is a knowledgeable ex-USN chap:

http://warships1discussionboards.yuku.c ... nts?page=3

"That blah-blog [this thread topic] looks to me like more of the normal "blow up every minor occurance into a major disaster) rant...

For example: "Apparently, the two F-35Bs involved in the sea trials had been diverted to Patuxent River to be repaired the previous week—presumably for fixes the crew on the Wasp were unable to perform."

Since Wasp has no F-35B maintenance equipment or tools aboard, and since none of its crew are trained F-35B maintainers, then OF COURSE they couldn't fix them! "

Check out the write up in this week's AvWeek. Very interesting stuff (which no doubt has BS foaming at the mouth).

spazsinbad wrote:

TEG, what about flameout possibilities due disrupted airflow for whatever reason (spin?) or some other temporary cause (fuel starvation due prolonged inverted flight?)? Pilots will need to know what is possible in any given situation and for sure at what height to stop relight attempts and 'get out and walk'. Very Happy

The current engine fleet is no where near as susceptible to inlet airflow disruption as the TF30s or other previous generations of engines that were known to need smooth-direct airflow into the inlets.

Fuel starvation may occur, but that in it's self will cause 'difficulties' in relights, you've introduced air into the fuel and control system on the engine, not to mention cavitated pumps, and emptied fuel delivery manifolds, etc. (Depending on the severity of the starvation.) Same deal for running a jet out of fuel, or not having the fuel delivery system configured properly. The 'oh $h|t' moment causes the situation in the first place.

I'm sure the pilots will be well aware of how the engine will react to being 'abused' to the point it quits, and how to coax it back to life again. Not to mention the envelope to do so, and the amount of time required. Look at our current Vipers, they too were chastised for 'relights' the early days, and now the Thunderbirds use them for hundreds of demonstrations per year. (All be it with the pesky JFS doors removed)

It's dumb comments like those above that get twisted and blown out of proportion by the news, who ends up influencing the media or public at large, that end up feeding some dumb-@$s in congress who has no idea how a modern combat aircraft/engine SHOULD work. This simply makes a problem out of something that is a no-brainer.

Basic Fix - Don't kill the engine while you're flying!

TEG

TEG, agree but stuff happens (in combat conditions?). Would be good if Mr.Wheeler could provide more detail but he is in the business of FUD. Fear Uncertainty & Doubt. Others are in the 'sky is falling' Chicken Little business. Given all the problem solving in F-35 development so far it seems that all the 'issues' are solvable.

I'm guessing 'sferrin' refers to this: 24 Oct 2011 issue? 'Defense
Navy Testers See Few Anomalies in F-35B Ship Trials'

http://www.aviationweek.com/aw/publicat ... content.do

http://www.aviationweek.com/media/image ... _aw_st.jpg

That's the one. Smile

That_Engine_Guy wrote:

Quote:

Some Suggested (and Unreported) Issues on the F-35 October 20, 2011 Winslow Wheeler

b. There are problems with being able to restart the engine in flight if it flames out.

The F135 will be the most advanced aviation gas turbine EVER.... guess the key here is that it should NEVER quit in the first place?
(Most us engine folk take this personal!)

Quote:

The F135 team has also issued a contract of its own to Diagnostic software maker Qualtech Systems Inc. of Wethersfield, CT to provide real-time on-board diagnostics for its jet engines. The contract calls for Qualtech Systems to provide fault isolation development software tools and an an on-engine "diagnostic reasoner" as part of Pratt & Whitney's Joint Strike Fighter Engine Prognostics & Health Management (PHM) Program.

PHM will make use of electrostatic and other sensors to monitor such parameters as debris generation, vibration, blade health and lubricating-oil quality. The suite of sensors will constantly monitor approximately 500 data streams, which will be integrated with the F-35's own systems. The complete PHM system has been developed in partnership with NASA Ames, which created vital data-fusion algorithms, NASA Dryden and NASA Glenn, with flight development to be carried out with a C-17. As noted previously, the aim is to predict the need for inspection or parts-replacement, so that, via a satellite link, the airbase or aircraft carrier knows the engine health before the aircraft returns from its mission.

Like most modern fighter jet engines; You're likely to NOT get a motor restarted after a serious malfunction, if it's serious enough to kill it in flight, it's serious enough for it to not relight.

My Two Cents

TEG

Kinda like this:

http://f-16.net/news_article4448.html

OMG you mean other fighters besides the F-35 have engine trouble from time to time?

http://www.youtube.com/watch?v=RcGx0oLX ... ideo_title

1st503rdsgt wrote:

OMG you mean other fighters besides the F-35 have engine trouble from time to time?

http://www.youtube.com/watch?v=RcGx0oLX ... ideo_title

They most certainly do - that why you need two.

Two to double your chances of an engine failure? Surely the 'health monitoring' of the F135 engine is going to make a big difference along with modern material/techologies outlined in previous threads about this issue. More accidents are caused by simulating/practising single engine military aircraft performance than actual real single engine emergencies. I read that somewhere. Very Happy

@TEG..... Using your super powers of engine intution can you guess what caused this?

Just encase you don't feel like using your super powers.....

http://cencio4.wordpress.com/2011/08/22/flameout/

Last edited by spazsinbad on Oct 25, 2011 - 09:18 AM; edited 3 times in total

'sferrin', is this the article you were referring to earlier above? ‘Bs on the Wasp’ by Amy Butler Aviation Week & Space Technology 24-31 Oct 2011 More info would be posted but then I would have to.... Cool

A lot of the 'so-called' unreported problems in first post of this thread were reported in this article. But I cannot reveal them because otherwise.... Rolling Eyes

Have not heard about the F-35C arrestor hook change until this article OR that any arresting trials were ongoing. Whatever.

And 'alloycowboy' have you read the thread about 'automatic A/B' during catapulting for the F-35C (similar to what was implemented on the F/A-18E/F to overcome what is illustrated above? Go to: [only partly reproduced below - for the convenience that is in it] Very Happy

http://www.f-16.net/f-16_forum_viewtopi ... r-asc.html

JBD Testing A Key Step For Joint Strike Fighter Aviation Week & Space Technology Jul 18, 2011 p. 84 by Amy Butler | Joint Base McGuire-Dix-Lakehurst, N.J.

http://www.navair.navy.mil/lakehurst/nl ... esting.pdf (125Kb)

"...Even without the more extensive data provided by today’s sensor array, Super Hornet engineers gained valuable experience during JBD trials that led to a change in how the aircraft is launched. During testing, hot air was inadvertently recirculated into the air intake of the Super Hornet, prompting a “pop stall,” or hiccup in the airflow for the propulsion system. The result was a dangerous fireball coughing from the back of the Super Hornet, says Briggs.

The design fix was the creation of a limited afterburner setting for launch. Engineers crafted software such that the engine is at 122% of military power when a pilot sets it to afterburner. By the time the jet reaches the edge of the deck, the system automatically opens the throttle to full afterburner at 150% of power without intervention by the pilot, says Briggs.

Having completed the first phase of JBD trials with a single F-35C, engineers are eager to test a more realistic scenario with one aircraft in front of the deflector and one behind.

Because of this lesson, the limited afterburner setting was designed into the F-35 in its infancy...."

spazsinbad wrote:

Two to double your chances of an engine failure? Surely the 'health monitoring' of the F135 engine is going to make a big difference along with modern material/techologies outlined in previous threads about this issue. More accidents are caused by simulating/practising single engine military aircraft performance than actual real single engine emergencies. I read that somewhere. Very Happy

Interesting re: the simulation / practice. But....

"In a single engine aircraft such as the Lockheed F-16, "a failure in any engine component that leads to a loss of thrust or flame-out equates to a quick attempt to try to troubleshoot the problem for a few seconds before making the decision to eject. In a Hornet, by contrast, even a total single engine failure can be ignored" if the situation warrants it, the [active F/A-18] pilot says.

Ideally, he adds, in the event of an engine failure, "flight can easily be maintained at a safe altitude while carrying out emergency procedures"."

http://www.flightglobal.com/blogs/the-d ... ngle-.html

maus92, this single engine / twin engine topic has been discussed earlier a few times. We can both duel with quotes. What is not taken into account is the 'health monitoring'. There is evidence that for example the twin engined Hornet when suffering a single engine failure has that engine damage the good engine that either at the time or afterwards before a successful landing results in a double failure. A recent example of what can happen was a USMC carqual Hornet being diverted ashore but erroneously for the sake of USMC convenience (rather than USN safety) NOT landing at nearest airfield but crashing at the further along USMC one. People on ground killed - pilot ejected OK. There is a huge topic right there about what a pilot responsibility is and not just twin/single engines.

spazsinbad wrote:

maus92, this single engine / twin engine topic has been discussed earlier a few times. We can both duel with quotes. What is not taken into account is the 'health monitoring'. There is evidence that for example the twin engined Hornet when suffering a single engine failure has that engine damage the good engine that either at the time or afterwards before a successful landing results in a double failure. A recent example of what can happen was a USMC carqual Hornet being diverted ashore but erroneously for the sake of USMC convenience (rather than USN safety) NOT landing at nearest airfield but crashing at the further along USMC one. People on ground killed - pilot ejected OK. There is a huge topic right there about what a pilot responsibility is and not just twin/single engines.

I do agree with you about the advance / importance of "health monitoring" in the F135. I'd rather have two engines than one - my personal preference.

Forum: General F-35 Forum

Some Suggested (and Unreported) Issues on the F-35 - Wheeler