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Can Harriers ground-taxi backwards?
Hopefully Frijoles or some other current or former Harrier
type can answer this (whatever happened to Cecil Turner?). Using braking stop it would seem at least theoretically possible, but I don't know if there were other problems that prevented it (hot gas re-ingestion/FOD, light on the wheels, etc). Assuming it is doable and NATOPS allows it, is/was it done rarely/infrequently/routinely on an LPH/LHA/LHD? I was just wondering if it were possible to taxi cross-deck and get lined-up, then backup to maximise T/O run, thus allowing more a/c to be launched in a short period of time than if it were necessary to use deck tractors for positioning. Or is the deck wide enough and the maximum angle of the Harrier's nosewheel steering gear great enough that it can taxi aft and then essentially make a U-turn at the aft end of the deck, wasting little or no T/O run? TIA, Guy |
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Guy Alcala wrote:
Hopefully Frijoles or some other current or former Harrier type can answer this (whatever happened to Cecil Turner?). Using braking stop it would seem at least theoretically possible, but I don't know if there were other problems that prevented it (hot gas re-ingestion/FOD, light on the wheels, etc). Not only theoretically but practically possible. Assuming it is doable and NATOPS allows it, is/was it done rarely/infrequently/routinely on an LPH/LHA/LHD? And permitted by NATOPS. After 513's first deployments on LPHs, the AV-8A was never routinely deployed aboard LPHs as they are aboard the LHA/LHDs [typically, a 6-aircraft det as part of the composite helo squadron of the MEU]. "Backing up" was routine, IME, but generally aircraft movement/spotting was planned such that it wasn't needed. I was just wondering if it were possible to taxi cross-deck and get lined-up, then backup to maximise T/O run, thus allowing more a/c to be launched in a short period of time than if it were necessary to use deck tractors for positioning. Or is the deck wide enough and the maximum angle of the Harrier's nosewheel steering gear great enough that it can taxi aft and then essentially make a U-turn at the aft end of the deck, wasting little or no T/O run? TIA, The latter, we called it the "conga line" was the standard practice. LHA/LHDs are wide enough to do that. Deck runs for the AV-8A, even for the most restricted engines, was always short enough to permit a 6-aircraft line-up to come down the starboard side, make the Uie at the aft end of the flight deck and then line up starting behind the 450' deck-run marker. Typically, a 55/55 STO would take 250-350', if twenty-mumble year old memory serves. -- OJ III [Email to Yahoo address may be burned before reading. Lower and crunch the sig and you'll net me at comcast.] |
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Ogden Johnson III wrote:
Guy Alcala wrote: Hopefully Frijoles or some other current or former Harrier type can answer this (whatever happened to Cecil Turner?). Using braking stop it would seem at least theoretically possible, but I don't know if there were other problems that prevented it (hot gas re-ingestion/FOD, light on the wheels, etc). Not only theoretically but practically possible. Assuming it is doable and NATOPS allows it, is/was it done rarely/infrequently/routinely on an LPH/LHA/LHD? And permitted by NATOPS. After 513's first deployments on LPHs, the AV-8A was never routinely deployed aboard LPHs as they are aboard the LHA/LHDs [typically, a 6-aircraft det as part of the composite helo squadron of the MEU]. "Backing up" was routine, IME, but generally aircraft movement/spotting was planned such that it wasn't needed. I was just wondering if it were possible to taxi cross-deck and get lined-up, then backup to maximise T/O run, thus allowing more a/c to be launched in a short period of time than if it were necessary to use deck tractors for positioning. Or is the deck wide enough and the maximum angle of the Harrier's nosewheel steering gear great enough that it can taxi aft and then essentially make a U-turn at the aft end of the deck, wasting little or no T/O run? TIA, The latter, we called it the "conga line" was the standard practice. LHA/LHDs are wide enough to do that. Deck runs for the AV-8A, even for the most restricted engines, was always short enough to permit a 6-aircraft line-up to come down the starboard side, make the Uie at the aft end of the flight deck and then line up starting behind the 450' deck-run marker. Typically, a 55/55 STO would take 250-350', if twenty-mumble year old memory serves. Ogden, thanks very much for the reply. The reason I asked is I was wondering about this in the context of the maximum number of Harriers that could be reasonable launched for a single strike on smaller carriers like an Iwo Jima, Spain's Principe de' Asturias, Italy's Guiseppe Garibaldi or the RN's Invincibles, with shorter and narrower flight decks than an LHA/LHD. To take an example, Pd'A has a maximum take-off lane length of 575 feet, allowing a maximum of about 550ft. t/o run (from the nosewheel) if the main gear is backed up to the after edge of the flight deck (ie the aft fuselage is overhanging). Photos seem to indicate that they normally spot 2 a/c nose to tail for t/o if conditions allow (either fairly light loads or else high winds/moderate temps), but usually seem to park about 3 Harriers in an arc around the starboard aft end of the flight deck, with one more spotted for t/o, probably allowing a 450+ ft. t/o run for a/c 2, 3 and 4, if they taxi into position and don't back up once lined up. Although their flight decks don't seem to be significantly wider than the others, the Invincibles islands appear to be narrower, with enough room to park Harriers (at least, the shorter-wing Harrier I variants) at an angle, abreast the island and clear of the foul line, so theoretically they could taxi aft when it was their turn and turn around. Pd'A and Garibaldi don't seem to have that much width abreast the island, although their islands are shorter so they could taxi a/c parked forward of it aft, once it was clear to do so,and with some time delay. Tests carried out by the USN on Pd'A with AV-8Bs (-406 engine) to establish flight limits and t/o requirements showed that in tropical day conditions (presumably 103 deg. F at SL) with 30kt. WoD, at a weight of 28,700 lb. for a CAP mission with two tanks, gun and ammo and 4 AIM-9s, an AV-8B would need to use the entire 550 ft. deck run. The radar-equipped AV-8B+ now used by the USMC, Spain and Italy has about 2,000 lb. more thrust from the -408 engine than was available from the AV-8B's -406, but the empty weight is about 1,000 lb. more too, and I don't know if there's a net gain or loss in STO performance for the same load. Under the same conditions from a flat-deck (no ski-jump) ship like any of the US phibs, -406 engined AV-8Bs were unable to take off with anywhere near that load, being restricted to a maximum of approx. (eyeballing the graph) 26,500lb. if taking the maximum LHA/LHD deck run of 800ft. Even with a more typical strike load of 6 x Mk.82 snakeyes, gun and ammo and ECM pod, it still grosses 26,982 lb., which is still over the maximum possible t/o weight using the entire deck (again, Tropical Day conditions). Since we and other countries have been flying most all of our combat and potential combat missions in tropical conditions (those numbers seem fairly representative of the Persian Gulf/IO), I'd think the need to make max. t/o runs would be pretty routine for such loads. Assuming that's the case, the ability of the a/c itself to taxi until lined up and then back up to allow it to use the max. t/o run, should decrease the t/o interval between a/c and thus allow more a/c to launch as part of the same formation. I know the USMC pilots on the Guam for the tests back in '73 and '74 weren't too keen on cross-deck taxying when the anti-skid coating was worn, as the Iwo Jimas had a rep for rolling. They would have preferred a turntable at the after end of the flight deck, similar to the ones on the vehicle/tank decks of LSTs etc, that would allow them to taxi all the way aft and then be rotated 180deg. into t/o position. But in addition to the extra cost that involved lots of weight at flight deck level and dependence on complicated machinery exposed to the weather, so it didn't feature in the final SCS design (of which Pd'A is an slightly stretched version). Guy |
#4
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