Based on a purely aesthetic
evaluation, I'd lay my money
on the Lockheed-Martin
entry (the X-35A) being accepted. It does, indeed, look like a smaller F-22
. The Boeing
version, on the other hand, looks quite a bit like a hungry cow
, with an extremely large under-nose air intake
and high-mounted delta wing
that give it a bit of a 'pregnant' appearance. As of the first week of July, 2001, both models have demonstrated some form of vertical flight. The X-32 has performed ASTOVL
flights, and the X-35A has made several VTOL 'push-ups' to varying heights. Both companies, naturally, have released promotional videos onto the Internet with (what else?) Top Gun
-derivative soundtracks (in some cases, a direct rip).
Some other notable facts about the two competing designs. The Boeing version uses a fairly conventional directed-thrust system like the one found on the AV-8B Harrier to achieve powered lift flight; the main engine thrust is vented down and ducted thrusters in the wingtips and nose stabilize and control the plane. The Lockheed-Martin entry, on the other hand, uses a lift-fan system, in which engine thrust is used to spin large downward-facing fans to provide lift.
The lift fan is a bit of a gamble. Past attempts at workable lift-fan systems have never been able to extract a thrust ratio high enough to make it worth the losses incurred by the mechanical workings of the fans. Lock-Mart is betting that they will be able to make it work by widespread use of advanced materials technology (composites, mostly) for the fans and mechanisms. They claim that the lift-fan system is lighter than the ducted thrust mechanisms found on the X-32, at around 3,000 lbs for the ducted thrust and 700 lbs for the lift fan; however, Boeing has countered by pointing out that the X-35A's engine is heavier by approximately 2,500 lbs, negating any difference.
Sources: Aviation Week, CNN, Boeing and Lockheed-Martin web pages
One small dispute with ApoxyButt
's writeup. While it is true that Lock-Mart
experience, it is not true that their entry is "less innovative" - at least not in terms of design. The ASTOVL
version of the Lockheed prototype
generates vertical thrust using lift fan
s, which would mark the first time lift fans have been used in a mass-produced
military aircraft. Like the AV-8B Harrier
and Yak-36 Forger
, the Boeing JSF prototype
utilizes ducted thrust
, using directional nozzles and vanes
, for vertical lift. This latter is a known and deployed system.
It may be that the innovation referred to is contained in the production plan from Boeing; the cost savings trumpted by Boeing (see ApoxyButt's writeup for more) do result from less-than-traditional manufacturing methods.
To tweak Karma Debt's writeup as well, it appears that the contract figure is for roughly $200 billion, not $300 billion...and remember, a billion here, a billion there, pretty soon you're talking real money!