CTR,
You ask, "..the aircraft is can be fitted with an additional internal tank
to provide 1000 NM total range. Why don't you use this 1000 NM range?"

As I have said now SIX times, the 609 cannot hover with that fuel and tank,
even when it has zero pax or payload. The hover weight is rigidly limited
by the rotor performance. With all the power the 609 has, it can only hover
with enough fuel to go 750 NM, leaving all passengers home. THAT IS WHAT THE
PAYLOAD RANGE CHART IS FOR, to tell you how to make the tradeoff between
fuel and payload, at a fixed hover takeoff condition.

You are clearly one of those guys who thinks a rotorcraft is like your car,
fill the trunk, fill the seats and fill the gas tank. That is not how we
can operate. The 609 can hover at 16,800 lbs, not one pound more. Its
empty weight is 11,300 lbs, then it must carry no more than 5500 lbs of fuel
when it starts its journey. In cruise, the 609 needs about 7.4 lbs of gas
to go one mile. Therefore, it goes about 750NM with no pax. If we add one
pax, we take out 170 lbs of gas, and its range drops by 23 NM. Get the
picture?

Now, if you are at an airport and want to allow rolling takeoffs, and load
the aircraft up until it cannot hover, that is fine, but don't try that at
Wall St heliport, the sound of proprotors cutting light poles is offensive
to the neighbors. Don't try that off an assault transport, the marines in
back do not have water wings. If the tilt rotor cannot hover at the start of
its mission, it cannot do the mission. Rotorcraft missions need rotorcraft
performance, thus we publish the performance with a hover at the start, so
that we can take off from small places, the reason why folks buy our
machines.

Get the picture?

Tilt rotors carry half the payload to the same range as helos, and cost
twice as much per ton of payload to do it.

Nick


"CTR" wrote in message
oups.com...
Nick,

I thought arrogance was limited to fast mover pilots. Most of the helo
pilots have worked with actually answer questions instead of degrading
the people asking them.

So why don't we try this again. And instead questioning the
capabilities of the questioner, answer the questions:

And to keep it specific and to the point, one question at a time. Lets
start with a straight forward one.

You use 750 NM 0 load range for the BA609. However the site you
reference in your presentation notes that the aircraft is can be fitted
with an additional internal tank to provide 1000 NM total range. Why
don't you use this 1000 NM range?

Carlos A. Fenny

AKA Civil Tilt Rotor

Note: In 29 years I have worked, hydraulics, mechanical controls,
landing gear, flight test, canopy/escape systems, composite structure
and advanced design.