Red Snow
My understanding (you may know better) is that the current UK MOD Plan A is to buy some STOVL variants of which ever JSF contender wins. I know nothing about the X-32 programme and very little about the X-35.
It seems to me that when politicians have big hopes for their military influence, but at the same time are not able to afford massive forces to exert that influence, then operating site flexibility becomes particularly important. So, I believe the UK should always have some top quality operational aeroplanes that can also do STOVL.
The operational capability (as opposed to the STOVL performance) of our current STOVL aeroplanes has been well preserved. The current clearance for all RAF GR7 mates to operate visually at low level in the dark using totally synthetic vision aids is a remarkable capability that few nations share. Likewise, for many years now, the RN FA2 has led the way in European air arms as the most effective BVR interceptor thanks to its AMRAAM capability.
But what about the STOVL bit?. The KISS Pegasus way of providing that has to be getting ever closer to its sell buy date. There are many reasons for this, but probably top of the heap is that it can never be used as an efficient supersonic powerplant – no matter how many corners you squirt fire from..
The X-32/35 ways of providing STOVL are very different. Both appear to have particular but different strengths and weaknesses.
Weaknesses first.
Boeing have to generate enough thrust in the hover to meet the bring back needs. But critically they must also keep the hot air out of the intake. Whether they will succeed in that remains to be seen.
Lockmart have not taken any chances with that and are using nice cold fan air to hold the front up. Driving that fan without wasting weight is a very demanding mechanical engineering task. But it is only mechanical engineering and do we seriously think that the clutch and gearbox issues are insoluble? Surely not? However, since the fan intake could never allow the fan to breathe at high forward speed, the fan cannot be used to help ACM. If the only thrust you can vector in ACM is at the back you are more limited.
The advantages?
Boeing can vector all of their installed thrust in ACM. That could provide some quite awesome tactics for the driver.
The Lockmart fan has to be a very efficient and calm way to generate hover capability. This will really help bring back capability and operating site issues. The drive may also be suitable to power specialised bits of combat kit that need massive bursts of power.
Bottom lines?
IMHO if the Boeing STOVL version is made to work it will be top dog in combat, but Lockmart seem to have an easier task on their hands so far as doing STOVL is concerned. If they both fail then UK needs a Harrier III. But who considers failure?
JF
PS Sorry, forgot your point about flying them against each other. Do you mean the current overall competition or a special flyoff? I see these as two X programmes to validate two different concepts. So don't think it right to fly one against the other and say the better one in the sky goes ahead. There are too many other factors to consider surely?
JF
[This message has been edited by John Farley (edited 21 September 2000).]