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Finallyfound it:
http://www.pogo.org/m/dp/dp-v22-dote-092005.pdf A quick synopsis: OT-IIE safety and reliability issues have been put to rest. The Block A a/c used for OT-IIG still aren't full up with all operational gear, but most of that is easily added (and will be in the Block B full-up a/c); the most obvious of these are the ramp-mounted M240 and the hoist. Naturally, the Block B a/c will be heavier, which will affect performance for some of the mission profiles. The Block A a/c will be used for training, or else brought up to full operational standard via retrofit. Performance-wise, it's a mixed bag. For troop lift missions, the a/c easily exceeded all the spec profile radii and cruise speed, and the Block B a/c should also do so, albeit by a slightly smaller margin. For the two external lift missions the Block A a/c exceeded the radius specs, the Block B a/c is projected to fall short under the spec operating conditions. I've listed the threshold requirement in the spec, the performance demonstrated during the tests as well as the projected performance for both Block A and B, when the demonstrated performance is corrected to the spec conditions of altitude and temperature (the weather and terrain during the tests refusing to exactly match the conditions stated in the specs). All distances given below are the combat radius, except for the self-deploy mission which is ferry range. Mission spec abbreviations used are as follows: "AP-AR", Amphibious Pre-Assault Raid, carrying 18 troops, incl. 30 min. loiter in target area; "LAEX", Land Assault External Lift, 10,000 lb. load from 3,000 ft.PA/91.5 deg.F LZ zone to same, drop and return; "AEXL", Amphibious External Lift, 10,000 lb.from ship at SL/103 deg.F to LZ at 3,000 ft./91.5deg.F, drop and return; "ATRL", Amphibious Troop Lift, 2 round trips without refueling ea. carrying 24 troops from SL/103deg.to 3,000 ft./91.5deg.; "LATL", Land Assault Troop Lift, 24 troops from 3,000 ft./91.5deg.to 3,000 ft.91.5deg, offload and return; "SELD", Self Deploy, ferry mission with one AAR. Profile / Req. / Dem. Perf. & % +-/ Block A Proj. & % +-/ Block B Proj. & % +- AP-AR / 200nm / 230nm +15% / 247 nm +23.5% / 247nm +23.5% LAEX / 50nm / 69nm +38% / 63nm +26% / 29nm -42% AEXL / 50nm / 89nm(*1) / 115nm +130% / 40nm -20% ATRL / 2 x 50 nm / 2 x 53nm +6% / 120nm +140% / 122nm +144% LATL / 200nm / 210 nm +5% / 279nm +39.5% / 228nm +14% SELD / 2100nm / 2,660nm (*2) / NA / 2,400nm +14.3% Cruise Speed / 240 kts / 255 kts +6.3%/ 255 kts +6.3% / 250 kts +4.2% *1 6,900lb. vehicle *2 Extrapolated performance for Block A with Block B auxiliary fuel tanks The shortfall in external lift radius, especially the land external lift mission @-42%, is fairly major. There are work arounds, but it seems pretty clear that barring an engine upgrade the a/c will fall well short under the spec conditions. OTOH, for troop lift (which is, after all, the primary mission of the a/c), the a/c's performance is uniformly excellent, with the Block B exceeding the specs by from 14 to 144%. Cruise speed and self-deployment ranges are also well in excess of the spec. Some other issues include the lack of flight clearance to carry dual hook loads at night, owing to the radar altimeter being blocked by a load on the forward hook. This has been known about since OT-IIE in 2000, so I assume they didn't feel like spending the money to fix it by relocating the radalt antenna, until they were sure they got the big stuff fixed and the a/c was going to go into full production. I assume the same reasoning applied to the hoist and ramp gun. Oddly enough, CH-53s have the same problem, and given the increased likelihood of night ops nowadays this seems to me to be a major operational limitation for both a/c until it is rectified. Minor stuff: Owing to no longer being able to stow gear under the troopseats (to allow them to stroke in a crash), packs etc. either have to go on the center floor, possibly blocking rapid egress,or else have to be carried on the troops' laps, leading to discomfort on long flights. A contributory factor to this is that the seat pans are a couple of inches too short, leaving much of the load supported only by the troops' legs. Also, the seatbelts are unsatisfactory, having releases that are too small to be easily operated when wearing gloves, as well as being prone to falling behind the seats and being hard to retrieve etc. The seatpans will be extended and the seatbelts redesigned in the Block B a/c. There's a problem involving interaction between the SINGCARS radio and the flight displays, which should be cleared up by a software change to the latter. Crew chiefs are complaining that the left-side forward window in the cabin is too small for them to have a good field of view for maintaining a defensive scan, or when checking clearance when in a confined area. The right side doesn't have these issues because of the split pax. door on that side. The a/c's flight envelope still needs to be expanded out to its limits. During the tests, they were restricted to 60deg. of bank (i.e. 2g) and +-30 of pitch while maneuvering. Guy |
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