Re: another plane crash ...

Dave wrote:
> Yeti wrote:
>> Dave wrote:
>>> Brian Morrison wrote:
>>>> On Fri, 03 Jul 2009 22:12:44 +0100
>>>> Dave <davenpat@btopenworld.com> wrote:
>>>>
>>>>> nntp@benison.co.uk wrote:
>>>>>> On Fri, 03 Jul 2009 14:56:03 +0100, Brian Morrison
>>>>>> <scrapspam@fenrir.org.uk>
>>>>>> wrote:
>>>>>>
>>>>>>> Which has been known to work against them, even in a
Tornado GR1.
>>>>>> Or should that be especially in a GR1.  Never played with the
GR4
>>>>>> though!
>>>>> GR4's were limmited to subsonic speeds after MLU.
>>>>
>>>> Er, why?
>>>>
>>> The reason that a Tornado could reach Mach 2 was down to the variable
>>> geometry ramps at the front of the intakes. At speed, the ramps would
>>> come down from the top of the intake to prevent (I can't remember the
>>> terminology).
>>>
>>>
>>> I have remembered now, it is the shock wave of the air from going too
>>> far down the intake.
>>>
>>> Basically it was to prevent too much air punching down towards the
>>> engines and blowing out the flame. There used to be an AICS (air
>>> intake control system) that controlled the angle of the ramp
>>> according to the A/C air speed. There is a vent about 2 or 3 foot
>>> behing the front of the intake on top. This was there to balance the
>>> pito static system that the computers used.
>>>
>>> At the sides of the intake were spring loaded inlet vents that
>>> allowed extra air to go into the intakes.
>>>
>>> The above is a very scant description of how it worked
>>>
>>> Before MLU the RAF decided that they didn't need supersonic flight
>>> from the GR1's and it was decided to take out all of the AICS
>>> systems. This left space for other things to go into the avionic bays
>>> for GR4 enhancement.
>>>
>>> The ramps were controled by a hydraulic actuator and they were
>>> removed and replaced by an adjustable strut that was set once only.
>>>
>>> F3's were not affected.
>>>
>>> HTH
>>>
>>> Dave
>>
>> So, in fact, from what you're saying, the GR4s aren't actually capable
>> of supersonic flight, because without the variable ramps (as found on
>> Concorde, and the Tu144), the engines wouldn't stay running once the
>> air entering the intake became supersonic.
>
> I don't know the technicalites, but I would assume so. But that could
> only happen if the aircraft went into a steep dive. In level flight, I
> should imagine that the speed would be self leveling.
>
> I can only assume that the shock wave would be at the wrong part of the
> intake and blow out the candles. Once again, this is not my specialist
> area. Rolls Royce and MBB controled this area.
>
> Dave

I still regard SNECMA as the authority on Variable Intake Ramps... but I
always was a huge fan on Concorde, and even it's Russian 'sibling'.
[ Auf dieses Posting antworten ]