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Thread: Power of the DCS A-10C

  1. #11
    GOMER 2 Noodle's Avatar
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    When I designed the procedure, I test flew it with a heavyweight aircraft at the max drag index allowable by the 476 OI, with a temperature of ISA + 15. I was able to easily make the crossing restriction even under these adverse conditions. That being said, I didn't test it with an excessive tailwind. Perhaps that was an oversight.

    In any event, thats the real-world for you. The A-10C's engines are identical to the CRJ's, and we suffered from terrible climb performance too. If you're concerned about making the restriction because of the forecast winds, make sure you're flying the climb profile specified in the Dash-1...best climb speed gets slower as you climb.

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  3. #12
    Senior Member Baxter's Avatar
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    Or just notify ATC you will be unable to comply with the crossing restrictions

    Of course that's more of a 747 issue than an A10 issue
    Last edited by Baxter; 26Jan15 at 04:07.

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  5. #13
    Senior Member Kimi's Avatar
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    In addition to Tex's points , I forgot to mention in the Mass Debrief something I discussed with Frodo in the FLT debrief. Although not specific to night flying I think it's worth discussing.

    I presented a situation in where we have to do a long climb after departure or after egress, for the sake of familiarity I'm gonna use an A-10 VFR North dep as an example. Three options available after clearing Nellis' airspace (at DRY LAKE):

    1- Lead starts max performance climb and wingmen rejoin after level off. Fuel burn stays somewhat even for all flt members. Rejoin takes longer.
    2- Lead starts climb at 700 ITT to allow wingmen to rejoin on the climb. Helps establish formation faster but in turn has wingmen burn more fuel than lead.
    3- Rejoin and then start a max performance climb. Expedites formation establishment and has even fuel burn, and since rejoin is faster at level flight, leg time will be a bit longer than prevoius options.

    It's worth noting that 200 KIAS @6000ft MSL is slower than 200 KIAS @15000ft MSL.

    The main factor here is not fuel burn as a number, the actual gross weight delta due to uneven fuel remaining between flight members is. This becomes more of a factor during 3-ship or 4-ship flights. On one hand, it gives the second element the speed advantage as they'd always be lighter than the lead element. On the other hand, as what happened yesterday, the joker/bingo of the flight is dictated by the lightest a/c in the FLT so that would mean not optimizing the playtime of the FLT. Yesterday the delta bewteen Knight 21 and Knight 23 was 500 lbs when -3 hit joker.

    In my opinion option (3) sounds more optimal than the other two, both for faster rejoin and smaller fuel delta. It's funny because as lead I've always done option (1), but now that I've analyzed the situation it doesn't sound as good as (3).
    Leg time doesn't seem much of a factor to me. In the case of a mission with DTOT, it doesn't matter how fast you get there, getting there on time is what counts.

    Any thoughts?
    Last edited by Kimi; 23Nov16 at 13:24.

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  6. #14
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    Wingman will always have greater fuel burn no matter how you turn it around. Consider just the throttle movements to maintain formation.

    1/2/3 I'd chalk down to lead's discretion and given situation (traffic, weather, etc..).
    Last edited by Energy; 23Nov16 at 13:53.

  7. #15
    Retired Pilot Tex's Avatar
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    Standard contract is 750ITT, 200 KIAS for the rejoin in the climb. Lead can brief non-standard procedures if the situation warrants. Your 3 presented options would all be a 'non-standard' variation from the contract but depending on what lead felt was required, all 3 could be viable options. Weather would also be a major factor as you don't want to try and rejoin in a cloud deck.

    As Energy mentioned, load/drag being equal, -2 and -3 will burn more fuel than lead as they jockey throttles to maintain position. The 500 lb difference was a cumulative effect from the whole flight.

    And I disagree about the leg time and DTOT. It absolutely matters how fast you get there for a few reasons
    1) You plan your route to minimize time in the threat area. You should be flying at or close to 750 ITT during ingress. Any slower and you are just extending the time in a WEZ.
    2) Energy management. Its not obvious in the sim but the A-10 does not have excess thrust. In mountainous terrain, you don't want to get slow/behind on energy. With a combat load out, losing an engine in 14,000' mountains is not a good place to be at any speed. Starting at 200 KIAS gives you much less time and options.
    3) Deconfliction/synchronization. If you have a DTOT it is generally to deconflict from other flights or to synchronize your flight with a support asset. That relies on you being predictable.
    “Rules are made for people who aren't willing to make up their own. " - Chuck Yeager

  8. #16
    Senior Member Kimi's Avatar
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    Quote Originally Posted by Tex View Post
    Standard contract is 750ITT, 200 KIAS for the rejoin in the climb. Lead can brief non-standard procedures if the situation warrants. Your 3 presented options would all be a 'non-standard' variation from the contract but depending on what lead felt was required, all 3 could be viable options. Weather would also be a major factor as you don't want to try and rejoin in a cloud deck.
    I agree on the 'non-standard' part. Maybe i have the wrong definition of performance then.
    Contracts say 200KIAS @750ITT for a standard climb, right? Does that mean we keep the 200kias throughout the climb or do we substract 1 knot per 1k ft?
    The defference with a max perfomance climb would then be that it's max pwr, right?
    Do contracts define when to start a climb?

    The fuel delta will always exist, I agree. Both (1) & (3) where thought on the process of mitigating that delta using max or standard climb for all flt members and only to rejoin level flight at 200 kias.

    Quote Originally Posted by Tex View Post
    And I disagree about the leg time and DTOT. It absolutely matters how fast you get there for a few reasons
    1) You plan your route to minimize time in the threat area. You should be flying at or close to 750 ITT during ingress. Any slower and you are just extending the time in a WEZ.
    2) Energy management. Its not obvious in the sim but the A-10 does not have excess thrust. In mountainous terrain, you don't want to get slow/behind on energy. With a combat load out, losing an engine in 14,000' mountains is not a good place to be at any speed. Starting at 200 KIAS gives you much less time and options.
    3) Deconfliction/synchronization. If you have a DTOT it is generally to deconflict from other flights or to synchronize your flight with a support asset. That relies on you being predictable.
    Yeah, you're absolutely right.

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  9. #17
    Retired Pilot Tex's Avatar
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    Moving the discussion to the public TTP forum as its a good discussion. I found this old thread that is related rather than start a new thread....
    Last edited by Tex; 23Nov16 at 20:42.
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