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Boeings C-5 competitor

Discussion in 'General Topics' started by NovemberEcho, May 17, 2017.

  1. Flyinthrew

    Flyinthrew Well-Known Member

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    Intake Suction Doors! I thought it was only a Harrier thing. It makes sense though. Those are really air hungry engines at a very low ram air pressure.
     
  2. JeppUpdater

    JeppUpdater Well-Known Member

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    Here's a classic video I had almost forgotten about.

    Honeywell ran this 720 for years out of Phoenix doing engine testing. I'm afraid it may be gone now.


     
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  3. MikeD

    MikeD Administrator Staff Member

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    Just like the spring loaded BIDs (Blow In Doors) atop the intakes of the F-117.
     
  4. MikeD

    MikeD Administrator Staff Member

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    I remember it well, have seen it many times, along with their B-26 Invader they had and their Falcon 20.

    The Falcon is gone, the B-26 is at South Mountain High School, and the Boeing 720 is no more.....all replaced by a 757.

    Here:

    https://forums.jetcareers.com/threads/the-last-boeing-720-kphx.108022/#post-1484338
     
  5. MikeD

    MikeD Administrator Staff Member

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    Remember the C-5 hit by the MANPAD on takeoff from Baghdad in '04? So they get it fixed there after weeks of being a mortar magnet, and I get tasked to lead a 2-ship out of Kirkuk to Baghdad in order to "cover" it as it takes off from Baghdad Intl and finally gets out of there and to Germany. Briefing went something like this:

    Me: "So....uhhh, what are my wingman and I supposed to be doing?"

    Intel O-5 REMF: "You'll be covering the C-5 and protecting it as it takes off from Baghdad."

    Me: "How am I going to do that?"

    Intel REMF: "Well, you need to protect it if it comes under any AAA or MANPAD fire."

    Me: "Ok, well, since the whole area surrounding the airport is urban, do I have weapons-free clearance to fire at will into the city if I see anti aircraft fire coming from somewhere? Because lets face it, if someone pops off a MANPAD, I won't have time to say "Hey!" over the radio before the C-5 is hit again, and besides, what the hell is the C-5 going to do anyway? Jink? And too, you have us loaded with Mk-82s and 30mm.....am I cleared to expend into where I see the shot came from? Since there likely won't be a C-5 I'll need to be flying cover for anymore...."

    Intel REMF: "Uhh, well no, you have to get cleared to return fire, you can't just expend ordnance into the city."

    Me: "So.....whats my mission again and how am I supposed to cover the C-5, besides be witness to it getting shot down?"

    Intel REMF: "Just go out there and fly the goddamn mission!"
     
  6. JeppUpdater

    JeppUpdater Well-Known Member

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    Mike, since you're likely the only person in this thread with first hand experience with them (and let's face it, in a much cooler airplane than a C-5 or 707/720) - did you ever get a chance to press on the doors in the -117? I'm wondering what kind of air pressure differential it takes to actually override the spring pressure for them to open.
     
  7. MikeD

    MikeD Administrator Staff Member

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    Yes. Takes probably 30-40lbs of weight to get the spring to open.

    They're flush with the fuselage so well, that ARFF folks had to be trained that the top of the intakes were not a safe walking or weight bearing area, if they were walking atop there for pilot rescue, etc. They'd get a surprise when they fell through them and into the intake.

    The BIDs existed due to the "ice cube tray" intake screens that covered the intakes. These screens extended stealth coverage over the intake holes. However there were severe restrictions on asymmetric flight, namely during single engine flight, that would cause compressor stalls due to the ice cube trays. The BIDs prevented that and would cycle open as necessary during slow, higher AOA, or asymmetric flight. The ice cube trays were also susceptible to......icing. And there was a "windshield wiper" arrangement on the bottom of the intake that could be cycled for ice removal.
     
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  8. MikeD

    MikeD Administrator Staff Member

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    Intake inspection through the BID doors. The ice cube tray intakes are clearly shown, and you can just barely make out the "windshield wiper" in it's stowed position at the bottom of the intake.

    image.jpeg
     
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  9. Bear

    Bear Well-Known Member

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    "The C-5 had the highest operating cost of any weapon system, and the trend was rising in tariff rates and reliability and maintainability costs for the C-5. The maintenance man hour per flying hour illustrates the difficulties in the C-5 force. The A models consumed 46.0 maintenance man hours per flying hour, 16.7 for the B model (CY96 data)." http://www.globalsecurity.org/military/systems/aircraft/c-5-serv.htm
     
  10. Skåning

    Skåning Well-Known Member

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    A sweet song indeed!

     

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