Fast Hawk
First time I dropped a bang was in a Jumping Bean T4 on an air test near Düsseldorf. Nobody noticed - or maybe they were used to large bangs from a few years earlier!😈
In in later life, I used to do it pointing at the ship at the end of an air test. 40k, roll inverted and pull. Trick was to recover before exceeding the IAS limit on the big tanks.
Happy days!
Mog (WIWOH!)
In in later life, I used to do it pointing at the ship at the end of an air test. 40k, roll inverted and pull. Trick was to recover before exceeding the IAS limit on the big tanks.
Happy days!
Mog (WIWOH!)
In the early days of the Hawk T Mk 1 at 4FTS, unexplained boom complaints from the Viet Taff were occasionally received by the station.
It turned out that extending the airbrake at high IAS was the cause - I don't know whether it was subsequently fixed?
It turned out that extending the airbrake at high IAS was the cause - I don't know whether it was subsequently fixed?
BEagle
The best a Hawk T1 can do in terms of IAS is 550 knots.
Sea level, Mach one is approximately 660 knots.
Could an extended air brake at high IAS really cause the airflow to exceed the Mach? Besides which the extent of the airbrake extension would be limited by the high IAS.
I’m not saying you’re wrong it’s just something I’ve never heard before. Surely, if true, it would have been part of the infernal A2 groundschool I was forced to endure?!
BV
Sea level, Mach one is approximately 660 knots.
Could an extended air brake at high IAS really cause the airflow to exceed the Mach? Besides which the extent of the airbrake extension would be limited by the high IAS.
I’m not saying you’re wrong it’s just something I’ve never heard before. Surely, if true, it would have been part of the infernal A2 groundschool I was forced to endure?!
BV
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Hi BV,
I remember, as a stude on 4 FTS in the late 70s, the kerfuffle caused by using the airbrakes at high subsonic speed leading to mini booms all over north Wales. This seemed to mainly occur during GH aeros and tailchases.
The instruction we were given was to roll & pull buffet to reduce speed, rather than use airbrake to slow, if we were at high ish (> 0.85) mach. This not surprisingly led to some fairly agricultural applications of large G loadings before we were told just to SLOW DOWN (but not told how to!!).
I remember, as a stude on 4 FTS in the late 70s, the kerfuffle caused by using the airbrakes at high subsonic speed leading to mini booms all over north Wales. This seemed to mainly occur during GH aeros and tailchases.
The instruction we were given was to roll & pull buffet to reduce speed, rather than use airbrake to slow, if we were at high ish (> 0.85) mach. This not surprisingly led to some fairly agricultural applications of large G loadings before we were told just to SLOW DOWN (but not told how to!!).
[QUOTE][was to roll & pull buffet to reduce speed, rather than use airbrake to slow, if we were at high ish (> 0.85) mach/QUOTE]
And there in a nutshell is the point at which the seemingly continual tailplane replacement programme across the T1 fleet was born.
And there in a nutshell is the point at which the seemingly continual tailplane replacement programme across the T1 fleet was born.
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Which is a mere 360KIAS.....
I can't remember what the 'fix' was as I only did a pre-TWU refresher on the Hawk. But the mini-booms from the airbrake certainly annoyed the locals back then.
I can't remember what the 'fix' was as I only did a pre-TWU refresher on the Hawk. But the mini-booms from the airbrake certainly annoyed the locals back then.
I am a bit surprised by the apparent distress to the locals from these 'booms'. From memory from my time at Brawdy as an instructor on both Hawk and Hunter, all medium/upper air exercises were flown well out to sea either to the west or south west. There was no overland area available south of airway G1 and a transit to the north of it was impractical in both time and fuel terms. So these 'booms' would have been generated out to sea well beyond the earshot of Mr Zammett.
No the reported booms were whilst I was on my pre-TWU refresher at Valley. All 4FTS GH (apart from the high level supersonic exercise) was overland in my time.
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ROC Man.
The ‘tradition’ of carrying underwear on the supersonic run is 100% cast iron fact. On my course one fellow did get the wrong end of the stick and wore them - he was quite the spectacle at the outbrief as his other half was quite petite. I was (sadly) a little sheepish about the practice so I took my favourite soft toy - a rather strange eel about a foot long that doubles as a board cleaner when he wasn’t being a lucky talisman.
That eel was there for everything - supersonic runs, Ops, deck landings...
The ‘tradition’ of carrying underwear on the supersonic run is 100% cast iron fact. On my course one fellow did get the wrong end of the stick and wore them - he was quite the spectacle at the outbrief as his other half was quite petite. I was (sadly) a little sheepish about the practice so I took my favourite soft toy - a rather strange eel about a foot long that doubles as a board cleaner when he wasn’t being a lucky talisman.
That eel was there for everything - supersonic runs, Ops, deck landings...
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I flew many air tests at Valley in the early 80s. There was no call in the Air Test Schedule to do a supersonic run. After a timed climb to FL400, it was all gently downhill until the high speed run al low-level - nominally at 2000ft but sometimes a tadge lower!
There was no supersonic run on the FJ course (which I never did [the course]). But I was introduced to them by a venerable colleague who swore that the Hawk did not make a sonic bang; so my first experiences were directed at fields of sheep on the Lleyn.
I was not convinced so whenever I had a go, I checked that I was out to sea and got radar clearance for a "high speed" run. It got to be known around the students and I had no shortage of volunteers to fill the back seat.
It was pretty straight forward: half roll, pull to 45+ degrees nose down and half roll again. Handling and recovery were unremarkable.
The low-level run was more problematic. On some aeroplanes, 167 168 and 169 particularly, approaching 500 kts the turn and slip ball would edge out, and quite a bit or rudder was needed to correct. I took one to Dunsfold to be looked at and remember Andy Jones, the Hawk development TP, approaching the tailcone with a large screwdriver. Swapping the tailcone for the modded one with the large fillet and vertical rear largely eliminated the problem.
There was no supersonic run on the FJ course (which I never did [the course]). But I was introduced to them by a venerable colleague who swore that the Hawk did not make a sonic bang; so my first experiences were directed at fields of sheep on the Lleyn.
I was not convinced so whenever I had a go, I checked that I was out to sea and got radar clearance for a "high speed" run. It got to be known around the students and I had no shortage of volunteers to fill the back seat.
It was pretty straight forward: half roll, pull to 45+ degrees nose down and half roll again. Handling and recovery were unremarkable.
The low-level run was more problematic. On some aeroplanes, 167 168 and 169 particularly, approaching 500 kts the turn and slip ball would edge out, and quite a bit or rudder was needed to correct. I took one to Dunsfold to be looked at and remember Andy Jones, the Hawk development TP, approaching the tailcone with a large screwdriver. Swapping the tailcone for the modded one with the large fillet and vertical rear largely eliminated the problem.
That said, the only underwear involvement was a change on landing after a nasty fright, recovering from a high level loop !
The only booms on the Vampire supported the tailplane !
I started flying Hawk T1 airtests in the mid-80s and I am sure that the current dive to 0.98M was in the schedule by then. The directional trim change that occurs as you accelerate does vary from airframe to airframe and is associated with the tail cone. If you take the tailcone off, immediately refit it and then fly the dive again it can behave differently so it is very sensitive to rigging. There is inevitably a wing drop during the acceleration that requires about 1/3 lateral stick to maintain wings level although, again, it varies between airframes and there is some correlation with the sideslip due to the directional trim change. The recovery is flown wings level at 2.5g because there is a transonic pitch up during the deceleration and the normal acceleration limit at those Mach numbers is only 4.5g. All of this is fairly classical for a wing of that quarter chord sweep angle. I have to say that on this airtest profile I never felt that there was a particular risk of exceeding 1.0M inadvertently because there was always adequate nose up tailplane authority to reduce the dive angle if the acceleration was too high. However, if an airframe displayed atypical handling characteristics for whatever reason I could see how it could happen.
I have intentionally been to about 1.05M but I am intrigued to know how HS ever achieved the 1.2M limit!
I have intentionally been to about 1.05M but I am intrigued to know how HS ever achieved the 1.2M limit!
I asked JF the same thing and his answer was the aircraft had no true airframe mach limit as the aircraft was effectively self-limiting. The absence of a number didn't sit well with the customer though so the M1.2 number offered by the intake/propulsion team was used instead. The actual maximum achieved by HS was M1.17.
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RETIRED.
You may not remember. We could start the Mk5 at FL350, but then we were not weighed down with unnecessary things like fire extinguishers or bang seats.
You may not remember. We could start the Mk5 at FL350, but then we were not weighed down with unnecessary things like fire extinguishers or bang seats.
...... But dont knock bang seats, been there done that !!