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| Re: In Amber Clad loadout discussion | |
| Posted By: OldNick <nmascall@btinternet.com> | Date: 3/16/05 9:58 a.m. |
In Response To: Re: In Amber Clad loadout discussion (Zak Anderson) : I assume the russian fighter was the yak-141? If thats the case the F-35
Yes, I was talking about the Yak-141. The main jet nozzle for the F-35B variant works identically, and the back ends of the two aircraft are very similar for that reason. From www.airforce-technology.com/projects/jsf/ "The main engine has a three bearing swivelling exhaust nozzle. The nozzle, which is supplemented by two roll control ducts on the inboard section of the wing, together with the vertical lift fan provide the required STOVL capability." The lift fan provides a large proportion of the lift, but the main nozzle still makes a significant contribution. This may reduce the hot-exhaust problem, but certainly does not eliminate it. The lift fan is driven by a shaft from the main engine, so the power it uses still translates into jet exhaust. I cited the Yak-141 event mainly because it is the most vivid example I know of the ground-handling problems associated with direct jet lift, which appears to be the way Pelicans hover (maybe with an anti-grav assist). I hate to think of the power levels needed to support a 66-ton tank on direct jet lift alone - call it 150000 pounds of thrust, or four-and-a-half F-22 engines (F119-PW-100, 35000lbst each) running flat out. The downwash could probably flip an MBT. These ground-handling problems are not insuperable. The long-serving (since 1969 with the RAF) Harrier/AV-8 suffers from them to some degree, because the rear nozzle efflux is hot. You just need to be very careful, especially in confined spaces: jets cough, splutter, overheat and lose thrust when they re-ingest their own exhaust, and even if there's nothing flammable around, loose objects (even quite heavy ones) will go flying. This last problem obviously applies to cold efflux just as much as hot. | |
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