Forum: General F-35 Forum

Where is the IPP exhaust actually located on the production A's now? I've seen photo's with it on top, on the side and underneath so far.

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A&B have the exhaust on the bottom while the C has it on top.

Only the B model has downward facing IPP exhaust AFAIK. (previous page) "From LM ...In the F-35B (unlike the -A/C) the exhaust from the IPP points downward..." http://forum.keypublishing.com/showthread.php?p=1613080

Hmmm.... Seems like there are other interpretations though as per:

http://www.aviationweek.com/aw/blogs/de ... 049291946b

"...or IPP, which exhausts downwards on the STOVL aircraft. (It exhausts upwards on the F-35C carrier variant to protect deck crew, but downwards on the F-35B and CTOL F-35A to save weight and gain fuel volume.)..."

For those asking where the IPP inlet is.

As others have mentioned, the C model has the exhaust on top of the fuselage.

The IPP is a leap forward in vehicle sub systems architecture. It combines what used to be three federated systems, which in turn makes it very complex. Once the kinks are worked out, it will pay dividends for the pilot and maintainer. Hopefully this gets resolved soon.

LMAggie (& SWP), thanks for IPP info.

A short history of the subsystem that grounded the F-35 By Stephen Trimble on August 5, 2011

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

"It has been described by Lockheed Martin as "revolutionary" and a "lofty technology challenge" so important that it was included in Secretary Robert Gates' tour of the F-35 assembly plant in September 2009 (see photo above).

The power and thermal management subsystem is called the Honeywell integrated power package (IPP), and it is currently the reason why no F-35s are flying.

We don't know how long the grounding order caused by an undisclosed IPP malfunction on 2 August will last. Since the announcement landed in our email inbox at 14:14 on 3 August, the programme has been in communications black-out mode. Even its normally chatty Twitter page has gone silent. That is not a good or a bad sign, although it is never re-assuring. It really means we still don't know anything about the incident or its consequences.

But we do know many things about the IPP. This relatively unknown subsystem is one of the few innovations -- along with the shaft-driven lift-fan, electro-hydrostatic actuators and engine-mounted starter/generator-- that distinguish the F-35 as a technological trailblazer. The F-35 is one of the first "more-electric aircraft", meaning it uses electricity to replace several functions formerly fueled by hydraulics or pneumatics. The IPP is the heart of the power and thermal management system. Its roughly 200hp gas turbine engine sends power to the starter/generator, which powers on the F-35's engine, which, in turn, powers up the generator. The IPP then manages the air-cycle cooling system, plus acts an emergency power supply in case both starter/generators happen to fail.

The IPP has been the focus of concerns throughout the development and flight test programme. Here's a brief catalogue of the major issues that have surfaced since the IPP started the first F-35 test engine six years ago.

April 2005: IPP performs first engine start
21 Aug 2007: While operating in cooling bleed mode, the IPP shut down on the integrated test stand. The test stand was damaged as a result of the shut down and had to be refurbished, according to the Defense Contracts Management Agency (DCMA). An issue with a rotor was blamed for the shut down. "They believe that the rotor contacted the stator and gradually wore the stator, the rotor's sleeve and the enclosing magnet," DCMA reported.
October 2007: DCMA reports IPP oil samples have unallowable traces of nickel alloy. "Stator and rotor clearance issues within the IPP have been identified as the root cause. Design clearance corrections are being implemented, and a rebuilt IPP is forecasted for availability in late October following successful acceptance testing."
17 October 2007: Honeywell delivered a redesigned IPP to Lockheed Martin
March 2010: The Government Accountability Office (GAO) reports that exhaust from the engine and integrated power package exhaust may cause excessive damage to the flight deck environment and runway surfaces that may result in operating limits or drive costly upgrades and repairs of JSF basing options".

[No mention of fixes otherwise described in this thread then.]

http://www.flightglobal.com/blogs/the-d ... %20IPP.JPG
http://www.flightglobal.com/blogs/the-d ... Martin.jpg

The Evolution of Electric Military Aircraft 29 July 2011 Dr. Mark T. Maybury Chief Scientist
United States Air Force World Symposium on Electric Aircraft Oshkosh Air Show, WI

http://www.avweb.com/pdf/electric-aircr ... rcraft.pdf (5.4Mb)

BREAKING: F-35 flight tests may resume next week By Stephen Trimble on August 9, 2011

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

"A valve malfunction caused the F-35 grounding order last week. The Honeywell integrated power package (IPP) pulls in outside air to start-up, then switches to engine bleed air after the propulsion system comes online. The valve that switches the flow from inducted to bleed air didn't work, forcing highly compressed air to build up behind the valve until it essentially backfired. Ground tests may resume as early as tomorrow and flight tests could start again next week.

That information comes from Australian journalists who were briefed yesterday in Canberra by Lockheed Martin vice president Tom Burbage. Their news articles have not been posted yet, so there are no links to share.

As of yesterday, the joint programme office in Arlington, Virginia, remained in communications black-out mode."

So, If the IPP is a gas turbine it means the F-35 got natural gas (or similar) tank?

Jet engines, like the F-35's main engine, are also gas turbines. It doesn't mean it runs off natural gas. I'm sure the IPP runs off the main fuel tanks as normal.

dragorv wrote:

Jet engines, like the F-35's main engine, are also gas turbines. It doesn't mean it runs off natural gas. I'm sure the IPP runs off the main fuel tanks as normal.

I C, TNK U

dragorv wrote:

Jet engines, like the F-35's main engine, are also gas turbines. It doesn't mean it runs off natural gas. I'm sure the IPP runs off the main fuel tanks as normal.

Exactly right. The IPP runs off of the same fuel the main engine uses.

[quote="spazsinbad...the valve until it essentially backfired....."[/quote]

With over 1,000 hrs. of flight time and 100's of flights, I wonder if the instrumentation was indicating and alarming the impending backfire? Unlike older a/c types with "Start Carts" operated by a ground crews, are the SDD's being locally manned for monitoring or is the poor pilot sitting out there by his lonesome? No doubt the running around commenced, ..."after the fact", but were underware changes involved? Are backfires a common experience for others around jet a/c, they are not for me and mine?

nevermind

F-35 grounding explained by australianaviation.com.au August 10 2011

http://australianaviation.com.au/2011/0 ... explained/

"Lockheed Martin Aeronautics Executive Vice President and F-35 program head, Tom Burbage, was in Canberra on August 9 to brief media on the latest developments with the JSF program.

During the briefing, Burbage explained that the 20-strong JSF fleet’s recent grounding was a precautionary measure following the failure of an Integrated Power Pack (IPP) - a large APU-like component which provides starting power for the main engine and doubles to provide bleed air to cool the aircraft’s systems - on one of the flight test articles at Edwards AFB, AF-4.

“The airplanes are in a stop mode right now because we had a ground incident with an IPP about a week ago where we had a valve that failed,” Burbage said. “It’s (a)…turbine engine that’s driven by fuel and combusted until it starts the main engine of the airplane, and then the main engine takes over and runs it on bleed air. There’s a valve that has to open to shift from combusted to bleed, and there was a problem with that valve.”

Burbage added that there was an “explosive event” that was controlled by the aircraft’s onboard fire bottles. “There was a flame – we don’t know the extent of the damage yet,” he said. “There is some damage in the surrounding area, parched areas.”

Burbage said he hoped some of the aircraft could return to flight as soon as next week. “We’re hoping to get clearance to go back into ground ops as early as today, and return to flight ops on the instrumented airplanes as early as next week. We have 1500 flights and a thousand hours on that piece of machinery and have never seen this failure before, so it’s good we can identify these things early.”

There are currently 20 F-35s at flight test and training bases; six F-35As are at Edwards AFB for flight science testing and maturity flights; three F-35Cs and five F-35Bs at the US Navy’s Pax River facility and nearby JB Lakehurst-Dix-McGuire; two F-35As at Eglin AFB in Florida preparing for the commencement of crew and maintainer training; and four more F-35As at Fort Worth preparing for delivery to Eglin."

Forum: General F-35 Forum

F-35 fleet grounded after electrical subsystem failure