Roy Braybrook recalls being embedded with NASA…
Later in life, as a journalist, I had the privilege of interviewing
Harry Hillaker, “the father of the (General Dynamics, later Lockheed
Martin) F-16”. As a one-time preliminary design guy in the Kingston
project office, I told him GD had been incredibly brave to make the
YF-16 unstable longitudinally and relying on an autostabiliser to make
it flyable. Harry grinned, and explained that they had placed all the
wing spars at constant pitch, so they could simply move the wing back a
notch, if necessary.
We now take for granted the outstanding success of Ralph Hooper’s
P.1127, but in 1959 (with first flight of the prototype due in the
following year) its future was uncertain.
Churchill said that “You can always count on the Americans to do the
right thing – after they’ve tried everything else”, and the “trying
everything else” part had certainly been true of their attempts to
develop V/STOL fast jets. Hawker’s P.1127 gamble flew in the face of
most US experience.
The maths said the P.1127 would take off vertically and hover, and it
could obviously be made to fly conventionally. What nobody then
knew was whether it could reliably be transitioned between jetborne and
wingborne flight under unassisted human control by the average squadron
pilot, as was the company’s aim.
What was clear was
that Hawker (unlike GD with the YF-16) had no simple mechanical fix if
the P.1127 proved too unstable in transition.
Conventional wind tunnel tests at RAE Farnborough in
late 1959 showed that the P.1127 would be highly unstable
longitudinally during transition due to the jet-induced downwash
gradient at the tailplane. Whether it was unacceptably unstable
remained to be determined.
The only people who could find out in advance of
P.1127 flight trials were in a NASA team led by Marion McKinney, using
remotely-piloted powered scale models flown in the 30x60-foot open
working section of the Full-Scale Tunnel (FST) at Langley, Virginia. As
the tunnel airflow accelerated, the model would be transitioned from
hovering to wingborne flight. Comparison with the handling of earlier
US projects would give a good indication of whether the P.1127 would be
flyable or not.
The US role in the early development of the P.1127
has been downplayed for political reasons. The fact is that the US Air
Force wanted to know if a V/STOL fast jet was feasible and was willing
to fund NASA to find out, using various wind tunnel models including a
one-sixth scale in the FST.
As Robin Balmer’s then assistant on stability and
control (later ‘flight dynamics’) matters, I was sent to Langley at the
start of 1960 to provide liaison. I would like to write that I played a
crucial role in these very useful trials, but things panned out
differently. A problem arose in preparing the model for the first test.
I was assured that nothing could happen for at least a week so, if I
chose to attend an AGARD meeting on V/STOL in Washington DC, I wouldn’t
miss anything.However, unknown to me (or McKinney) an HSA director was
about to visit Langley.
So, while I was in the Pentagon, listening to a
Dutch presentation of a parametric study proving that V/STOL fighters
were impossible, NASA director John Stack was ordering McKinney to fly
the P.1127 model regardless. This explains how Kingston came to
receive a telex, from that HSA director, saying the model had
successfully flown through transition (on February 3rd, 1960), and
where the hell was your guy Braybrook?
The FST trials were only one element of the US
support provided to us in the early days of the P.1127 programme.
Then chief test pilot ‘Bill’ Bedford later said that the training he
and his deputy Hugh Merewether received on various aircraft and
simulators at NASA Langley and Ames prior to flying the prototype was
“a pearl of great price”. I felt (and still feel) the same way about
having been embedded with NASA.