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Question from my son re: F-15 et al


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Sorry just my 2 cents, but under the cockpit is the Nose Wheel well, aft of the Nose wheel well is Avionics Compartment 15, covered by you guest it Panel 15. Panel 15 is the one with the screened grate. What you have under that panel in that bay is the Regenerative Heat Exchanger and Secondary Heat Exchanger, the exhaust is on the spine with the air intakes between the Engine intakes and the nose barrel of the aircraft for the secondary heat exchanger and the exhaust for the regenerative heat exchanger is the circle louver on the side of the nose barrel. The prinimary Heat Exchangers are the intakes and exhaust .on the aft fuselage on the tail booms just below the vertical stab. ECS is beefed up on the Mudhen but is basically the same as the C/D models.

Cheers

Pardon me for being a weapons troop and not a spec or a knuckle dragger :thumbsup:

Im trying to remember something i saw while doing another job about 5 years ago that didnt deal with my primary AFSC. Be glad i was able to ID the chunk of equipment for what it was when i saw it, a heat exchanger. :lol: :woot.gif:

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no

offense intended. Uderstandable from a BB stacker.....

Pardon me for being a weapons troop and not a spec or a knuckle dragger :thumbsup:

Im trying to remember something i saw while doing another job about 5 years ago that didnt deal with my primary AFSC. Be glad i was able to ID the chunk of equipment for what it was when i saw it, a heat exchanger. :thumbsup::woot.gif:

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Huh?

Maybe there is an engineering requirements document somewhere, in which a manufacturer claims this is how his system is supposed to work.

In practice, especially in winter flying in Canada, I have suffered frozen feet while my upper body cooks and sweats under the sun coming in through the big canopy greenhouse.

The ECS systems in aircraft I flew never seemed to provide warmish air to the feet and cold air to the upper body to provide comfortable conditions in such a challenging thermodynamic environment (dark cool lower space, with bright sunny upper area). Next time you're driving your car with the sun streaming in on you, and your wife is in the shadow, if you're like my situation you tend to be overheating while she turns up the heat because the sun isn't warming her as much. Even split left/right car temp controls sometimes don't do the job, and cars have similar cold feet warm upper body problems.

Airliners and business jets have some kind of up/down split in environmental control. The vents at foot level pump out warmish air (with an auto or manual control that pilots and/or flight attendants control), while the vents from above (passenger-controlled nozzles) were supplied with far cooler air. In the Challenger business jets, that air was at 2 or 4 degrees celsius.

This is all a far cry from the days of the early jets. I enjoyed the cartoon of the P-38! In the T-33, with the ECS turned full cold, it was not uncommon for it to literally blow chunks of frozen water vapour into the cockpit from the vertical tube between front and back seats. Funny to see tiny snowballs being propelled up from this tube while flying! The worst thing in the T-33 was if you forgot to pre-heat the windscreen for almost half an hour prior to descent from a long cruise at 35,000 ft. The centre part of the windscreen glass was thick (supposedly bulletproof), and got cold soaked at high altitude. Descend into warm moist low altitude air, and you have fogging that won't clear until well after landing, meaning you have to look around the sides to see the runway when trying to land. The T-bird had a little electric heater and fan that you were supposed to turn on 30 minutes prior to descent, to warm up that glass.

Don't ask me how I know what happens when you forget!

:thumbsup:

ALF

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Maybe there is an engineering requirements document somewhere, in which a manufacturer claims this is how his system is supposed to work.

The cockpit outlet in the F-15 for ECS airflow is mounted on the instrument panel's center pedestal, which means your feet on the rudder pedals are well past it.

In practice, especially in winter flying in Canada, I have suffered frozen feet while my upper body cooks and sweats under the sun coming in through the big canopy greenhouse.

The ECS systems in aircraft I flew never seemed to provide warmish air to the feet and cold air to the upper body to provide comfortable conditions in such a challenging thermodynamic environment (dark cool lower space, with bright sunny upper area).

After a couple of years of instructing in the T-38, with the ECS controls up in the front cockpit, I started telling students in the brief that their grades for the flight would suffer if I had to tell them to turn up the heat; I was only partly joking. If I got bored enough on cross country flights I would put my water bottle in front of the cockpit air vent and see how long it would take to freeze solid.

In the T-33, with the ECS turned full cold, it was not uncommon for it to literally blow chunks of frozen water vapour into the cockpit from the vertical tube between front and back seats. Funny to see tiny snowballs being propelled up from this tube while flying! The worst thing in the T-33 was if you forgot to pre-heat the windscreen for almost half an hour prior to descent from a long cruise at 35,000 ft. The centre part of the windscreen glass was thick (supposedly bulletproof), and got cold soaked at high altitude. Descend into warm moist low altitude air, and you have fogging that won't clear until well after landing, meaning you have to look around the sides to see the runway when trying to land. The T-bird had a little electric heater and fan that you were supposed to turn on 30 minutes prior to descent, to warm up that glass.

Don't ask me how I know what happens when you forget!

You Canucks had all the neat stuff on your T-birds: better engines, better seats, and a fan. <_<

Regards,

Murph

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After a couple of years of instructing in the T-38, with the ECS controls up in the front cockpit, I started telling students in the brief that their grades for the flight would suffer if I had to tell them to turn up the heat; I was only partly joking. If I got bored enough on cross country flights I would put my water bottle in front of the cockpit air vent and see how long it would take to freeze solid.

You Canucks had all the neat stuff on your T-birds: better engines, better seats, and a fan. :crying2:

Regards,

Murph

Murph

I'm very happy never to have been your student - hard-nosed instructor pilots that will fail a stud because of cockpit heat are hard to please! ;)

And for sure we had the 'deluxe' versions of the T-bird. I just wish that Canada had not spent that money for all the fancy options back then; who knows, maybe we could have afforded Eagles instead of Hornets in 1982, if we had put the extra cash into Canada Savings Bonds instead?

And today, we might even be asking to buy Raptors! Last I heard, our current defence budget will be able to buy two or three JSFs and a few UAVs to replace our fighters... let's just hope they get the version of UAV control station with the USB-powered coffee cup warmers so that we can once again declare we have the 'best' version; just like the old T-bird!

ALF

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