Osprey vs. Harrier

Fred J. McCall wrote:
Guy Alcala wrote:

:"Fred J. McCall" wrote:
:
: Either you folks are operating some fairly dangerous aircraft or else
: you have a training problem.
:
:The Brit attack a/c spend a lot more time at low level than we do.

True for the Tornados. Not so much for the others, I don't believe.

The RAF's low flying page says of the large scale training excercise:

"most of those carried out in the UK will generally involve a mix of
Tornado GR1s, Harriers, Sea Harriers and/or Jaguars at low level"


and the pages mention every type except the nimrod, certainly I've seen
hercules doing lowish flying (below 2,500ft) whilst walking in the
highlands.


NB the RAF definitions of "low flying":


"Military fixed-wing aircraft (except Bulldogs and Fireflies) are
defined as low flying when operating within the UKLFS at less than 2,000
ft minimum separation distance (msd). In the case of helicopters,
Bulldogs and Fireflies, they are defined as low flying when operating at
less than 500 ft msd. 250 ft is the normal lower limit for low flying by
fixed-wing aircraft, although a very small amount of operational low
flying training for fast jet and Hercules transport aircraft is
permitted during the day at heights between 250 ft and 100 ft. Bulldog
and Firefly aircraft may be authorised to fly down to 50 ft msd while
helicopters can be permitted to fly as low as ground level."

In article , Iain Rae
writes
NB the RAF definitions of "low flying":


"Military fixed-wing aircraft (except Bulldogs and Fireflies) are
defined as low flying when operating within the UKLFS at less than 2,000
ft minimum separation distance (msd). In the case of helicopters,
Bulldogs and Fireflies, they are defined as low flying when operating at
less than 500 ft msd. 250 ft is the normal lower limit for low flying by
fixed-wing aircraft, although a very small amount of operational low
flying training for fast jet and Hercules transport aircraft is
permitted during the day at heights between 250 ft and 100 ft. Bulldog
and Firefly aircraft may be authorised to fly down to 50 ft msd while
helicopters can be permitted to fly as low as ground level."

Where does the 250ft limit cover geographically? I was on the end of
Blackpool south pier on Friday, two Jaguars were making very low passes
very close to the end of it (on the sea side). I couldn't estimate how
high they were, but it looked lower than 250ft to me (probably
misleading). I guess as the tide was in, they were over the sea so maybe
the limits are different?

--
John

On Mon, 11 Aug 2003 12:38:56 +0100, Andy Dingley
wrote:

I've been _blown_over_ by propwash from a low Hercules, whilst walking
on Salisbury Plain.

Yeah, I've drunk the Bishop's Tipple at that pub as well, I believe.

The ranges were closed (red flags out), but we
weren't on the range.

Of course not...

I did see a Herc and, later on, a Canberra fly below me once*.

Gavin Bailey

[*OK, I was 2,000 feet up a mountain on the west coast at the time.]


--

Another user rings. "I need more space" he says.
"Well, why not move to Texas?", I ask. - The ******* Operator From Hell

In article . net,
Robert writes
"John Halliwell" wrote in message

All twins should fly on one engine after a fashion, for conventional
flight this is not too big a problem. The trade off is smaller because
you can trade climb performance, altitude and airspeed (to an extent)
for the extra power needed, so you don't need twice the power needed for
take-off to fly.

You do to be certified for passengers.

That would require the aircraft to take-off fully laden on half the
available engines! Whilst some might be capable of doing it, I'd be very
surprised if it is a certification requirement.

Engine out on takeoff is a definite design issue that everyone has to deal
with.

True, but airlines have more ability to match the aircraft type and
take-off weight to the runways they expect to use them from. As you're
runway length tends towards zero, things become more critical.

Yes, but these are in service decisions (or procurement decisions I
guess).

The design requirement for power is to survive an engine out just after
reaching the "too fast to abort takeoff" speed at maximum weight.

Wouldn't that require V1 and V2 to be the same? How can you calculate
what V1 and V2 should be for certification given you don't know the
runway length and atmospheric conditions?

If you
don't have a big enough engine you have to restrict the plane to lighter
weight and/or longer runways.

Yes.

This relates to ETOPS in that you have to do this without exceeding redline
on the engine. And you have to be able to cruise on one engine in the safe
power range.

One of the "good" features of turbine engines is that if you don't care
about destroying them you can run them at like 150% maximum power for a few
minutes. This can gets you out of "oh ****" flying problems.

The V-22 IIRC is supposed to be able to land vertically on one engine,
and take off empty in an emergency on one engine. I'm not sure this
has been demonstrated yet.

The scenario I'm thinking of is a heavily laden V-22 leaving a carrier
with an engine failure occurring during transition. With very little
height or forward speed to play with (and the possible need to return to
the carrier for safe [vertical?] landing), it needs enough power to
maintain height on a single engine (by definition equal to its weight).

This supposed to be a high performance aircraft. You want to hang a round a
hot LZ while charlie-in-the-treeline or Abdul with an RPG shoots at you?
Having "excess power"
is a good thing. So the combination of "military power" and reduced
performance means you only need 1.5x as much engine as the minimum to hover.

Yes, excess 'power' (engine power) is a good thing, the problem with
VSTOL ops is that it is very expensive as far as extra weight goes to
keep the 1:1 thrust/weight ratio. The bigger the engines the more
power you need to lift the aircraft, the more power to turn them 90
degrees (bigger/heavier mechanisms, more weight, more power etc.). With
a built-in multiplier of 1.5x things are so much harder and weight
elsewhere in the aircraft will always be at a premium.

I don't have the figures to hand, but I guess a 777 has about 100K lbs
thrust to get a 3-400K lbs aircraft off the deck. The engine power
required is much more efficient for conventional aircraft.

Remember these are "prop" planes not rockets so it DOESN'T need
thrust = weight to hover, unlike a Harrier.

Yes, it does. The thrust generated by the 'props' must be greater than
the weight for it to lift off, must be equal for it to hover. The
'props' probably make the engines more efficient at generating that
thrust, but they must do so to lift it. Presumably the engines are rated
in SHP and not lbs thrust?
g
--
John

In article , Iain Rae
writes
We were ridge walking and did the hear noise, look up..., look
round..., look up again... "oh look he's down there" thing which you
get used to with jets but I still find odd with something that big.

Years ago I saw two pairs of Tornados very low over Thirlmere, I was
halfway up Helvellyn at the time.

--
John

Andy Dingley wrote:

:On Mon, 11 Aug 2003 09:16:34 +0100, Iain Rae
:wrote:
:
:and the pages mention every type except the nimrod, certainly I've seen
:hercules doing lowish flying (below 2,500ft) whilst walking in the
:highlands.
:
:I've been _blown_over_ by propwash from a low Hercules, whilst walking
n Salisbury Plain. The ranges were closed (red flags out), but we
:weren't on the range.
:
:LAPES, I think.

And hardly unique to the RAF. The original argument was that the RAF
has more accidents because they fly lower than USAF do.

--
"Rule Number One for Slayers - Don't die."
-- Buffy, the Vampire Slayer

Fred J. McCall wrote in message . ..
Iain Rae wrote:

snip

:The only info I have is for all RAF harrier types (GR7 and T10) from
:1988 to 2001 which lists the damage rate per 10,000 hours at 1.17.

snip

If you want to go by European loss rate per 10,000 hours, for
'fighters' (various aircraft types, of course) the data for 2000 looks
like:

snip

Britain - 0.15

snip

How much difference is there between loss rate and the major damage
rate? I ask because it seems frightening to me that the damage rate
for the Harrier is 8 times the loss rate of all British fighter types
in European airspace. Even if the difference is a factor of 2 then the
Harrier in RAF service is four times more dangerous then all fighter
types in RAF service in Europe.

If Europe is defined for the purposes of Fred's numbers to include
British airspace (which sounds likely from what he says about British
numbers being an order of magnitude greater then American numbers)
then the .15 loss rate for RAF fighter types seems to be a good solid
number that fairly represents the average RAF fighter type loss rate.

Then the question becomes how much improvement in loss rates has there
been since 1988? Has the Harriers loss numbers improved dramatically
since then? If the numbers are still roughly the same (they seem to be
from a curosary glance at the USMC numbers but I can't seem to find
good RAF loss rates numbers, because I don't know where to look) then
is something else wrong?

Chris Manteuffel

Andy Dingley wrote
I've been _blown_over_ by propwash from a low Hercules, whilst walking
on Salisbury Plain. The ranges were closed (red flags out), but we
weren't on the range.

B/f has been blown out of a tree by a tree-top skimming Vulcan. What
was he doing up the tree? He lived near an air base and the tree
seemed like a good vantage point to watch the Vulcan take off (which
was also the reason it was treetop skimming).

In message , Fred J. McCall
writes
Andy Dingley wrote:

:On Mon, 11 Aug 2003 09:16:34 +0100, Iain Rae
:wrote:
:
:and the pages mention every type except the nimrod, certainly I've seen
:hercules doing lowish flying (below 2,500ft) whilst walking in the
:highlands.
:
:I've been _blown_over_ by propwash from a low Hercules, whilst walking
n Salisbury Plain. The ranges were closed (red flags out), but we
:weren't on the range.
:
:LAPES, I think.

And hardly unique to the RAF. The original argument was that the RAF
has more accidents because they fly lower than USAF do.

Anecdotally seems to be the case, including personal experience (is that
an aluminium cloud overhead? No, it's just a Vulcan practicing low-level
flight...)

Hard to find solid evidence, though.

--
When you have to kill a man, it costs nothing to be polite.
W S Churchill

Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk

"Keith Willshaw" wrote in message ...

http://www.dasa.mod.uk/natstats/stat.../pdf/chap4.pdf

One of the problems is that a single collision can skew the figures
badly given the small numbers of the Harrier fleet

Indeed. The damage/10,000 hours operation is a useful stat, though,
which should be fairly accurate over the life of a long lived
airplane.

RAF Damage Rate/10,000 hours operation (over lifetime), sorted
descending order
Harrier: 1.19
Jaguar: 1.10
Tornado GR: 0.65
Hawk: 0.46
Chinook: 0.44
Puma: 0.37
Gazelle: 0.31
Tornado F: 0.29
Bulldog: 0.20
Wessex: 0.18
Sea King: 0.14
Jetstream: 0.09
Tucano: 0.08
Hercules: 0.04
Chipmunk: 0.04

RN FAA Damage Rate/10,000 hours operation

Sea Harrier 2.21
Merlin: 1.79
Sea King: 0.51
Lynx: 0.43
Jetstream: 0.08

The Army helo's are between .3 and .45

Note that while for most aircraft this is the average over the entire
history of the type, there are a few exceptions. The Harrier numbers
count trainers but, in the RAF case, not editions before the GR.7. The
Tornado numbers are also specific, the GR.1 and the GR.4, and the F2 &
F3 are split up.

Note two things: A) the Harrier is the most dangerous aircraft that
the British military operates, in terms of damage/hour operation,
exceeding all helocopters as well. B) RAF GR.7 & T.10 damage rates are
almost exactly those of the USMC in terms of damage/hour operation.

For all but the newest airplanes I think these numbers are fairly
accurate representation of damage rates. (e.g. the Merlin numbers
might be a bit high because it is so new, but as for the rest...)

Also, people who go low do worse then people who go high (compare
Tornado F versus Tornado GR).

That single loss translates into a loss per 10,000 hour rate
of 1.83. In that year there were no losses for Sea Kings so they
appear very safe.

So you have hours of operation numbers per year? Where? I don't see
them in this document.

I'll lay odds that after this years fatal mid air over the Gulf the
Sea King figures will look awful.

Yes, but I would think that the damage/10,000 hours over the entire
lifespan would take a hit, but not a serious one.

Chris Manteuffel