Re: Buying a BBJ and converting it to hydrogen

On Dec 23, 2:50 pm, Willie.Moo...@xxxxxxxxx wrote:
On Dec 24, 2:15 am, BradGuth <bradg...@xxxxxxxxx> wrote:



Good grief! For the same cruising range, perhaps using an A380 with
roughly 10% the passenger and freight capacity is a more than likely
alternative. Remember the amount of volume necessary for the LH2 is
not going to be all that unlike the shuttle ET, except you'll need
much more fuel storage capacity your unless cruising range isn't a
factor.
- Brad Guth

Willie.Moo...@xxxxxxxxx wrote:
I was going to call this what I did during my summer vacation! lol

All this discussion about hydrogen fueled airlines and such caused me
to spend a lot of time, a few minutes a least, thinking in detail
about what it would take to convert a conventional airliner to burn
hydrogen.

That and the stink some reporters on FOX made about Al Gore's carbon
foot print because he flew a private jet around - haha - caused me to
think about private jets conversions. I'm thinking about buying a
used BBJ - and a new one - which will be delivered in 7 years - and
when the old one is retired - having all the pieces and parts in place
to upgrade it.

The jet engine isn't difficult at all. The first jet engines used
hydrogen. In today's world NOx production can be a problem, but this
can be reduced dramatically by staged combustion of the hydrogen -
which entails burner changes. With these changes engineers who have
tested jet engines with hydrogen at the Dornier aircraft company, in
1998 and 1999 - were able to get hydrogen fueled jets to produce 2% to
the NOx of regular jet fuel powered varieties. That with a total
reduction to zero of carbon was great!

Alright, so take a look at slides 30 and 31 at the following URL

http://www.theoildrum.com/uploads/3246/csmith.pdf

On slide 30 is shown a hydrogen version of the Dornier 328. This
Dornier 328 shown here uses under wing nacelle tanks and a stretch in
cabin volume to increase it to 50 passengers - to take advantage of
the increased lifting capacity.

On slide 30 is shown a hydrogen version of the Airbus A300 - a
hydrogen version of the Beluga - which is basically a Beluga with
hydrogen tank up top, and a standard A300 interior below. Hydrogen's
high efficiency at longer range means they opted for longer range
aircraft here.

But we're looking at a Boeing BBJ variant. Here are the typical 737
specs - this is a starter for a preliminary analysis of what I have in
mind. This is a 737 800 a little bigger than the BBJ - but will do
for our purposes of a preliminary analysis.

737-800 Technical CharacteristicsPassengers

Typical 2-class configuration 162
Typical 1-class configuration 189

Cargo 1,555 cu ft (44 cu m)
Engines (maximum thrust) CFMI CFM56-7 27,300 lb
Maximum Fuel Capacity 6,875 U.S. gal (26,020 L)
Maximum Takeoff Weight 174,200 lb (79,010 kg)
Maximum Range 3,060 nautical miles (5,665 km)
Typical Cruise Speed (at 35,000 feet) 0.785 Mach

Basic Dimensions
Wing Span 112 ft 7 in (34.3 m)
With Winglets 117 ft 5 in (35.8 m)
Overall Length 129 ft 6 in (39.5 m)
Tail Height 41 ft 2 in (12.5 m)
Interior Cabin Width 11 ft 7 in (3.53 m)

So, has anyone ever seen a 747 carry the Space Shuttle Orbiter around?

http://www.murdoconline.net/2007/enterprise_atop_747-thumb.jpg

Compare that to the Airbus A300 hydrogen variant.

Does that suggest anything?

Sure does - what about an ADD ON TANK right on top of the 737? That
way you could store your tanks on the tarmac, refill them and lift
them in place, like changing batteries on a big energizer bunny.
Sweet.

So, fuel volume is 26 cubic meters. That means you carry around 20.8
metric tons of the stuff on a typical day. This translates to 890 GJ
of thermal energy.

Converting to hydrogen therefore which has 143 GJ per metric ton,
means that you need to carry 6.3 metric tons of hydrogen around with
you. Add in a fuel tank weight of 10% fuel weight, and that's 0.6
metric tons. Add interconnects and so forth, that's 0.1 metric tons.
A total of 7 metric tons of weight replacing 20.8 metric tons. This
adds 13.8 metric tons to the payload capacity of the aircraft.

Now,at 70 kg per cubic meter that translates to 90 cubic meters. 3.5x
as large as the jet fuel tank. Let's say we can occupy 60% of the
fuselage length above the CG with a tank - judging from the Space
Shuttle length atop the 747 transport ship. We might be able to do
more, but won't know for sure without detailed wind tunnel tests and
flow analysis.

60% of the 39.5 m length is 23.7 m. Dividing this dimension into the
total volume of 90 cubic meters comes up with 3.8 sq meters. Assuming
a constant circular cross section (as a first pass) produces a
cylinder 2.2 m in diameter and 23.7 meters long. Now a cylinder is
not ideal, an ideal shape would be some sort of tear drop shape that
has a much lower drage - up to 1/10th that of a cylnider, but the
volume and diameter relations would be within a factor of 50% of the
diameter calculated here - that is 3.3 m maximum diameter would be
near the right size of a optimally shaped tear drop holding the
requisite hydrogen.

A 26% increase in dimension allows a doubling of the fuel capacity
(with a reduction of payload gain to 6.8 metric tons) and an increase
in range to 8,000 km while increasing speed by 5% and other
improvements besides, like increase angle at take off, shorter take
off and landing runs etc, despite the increase in form drag (and
reduction in induced drag)

The 14 ton fuel tanks (and 1.2 ton empties) would be easily lifted off
the top of an aircraft that taxied under a loading crane - or had a
loading crane on a truck drive up to the aircraft - removing the empty
and loading up the full one. Several could be kept at airports that
served hydrogen fueld 737s.

So, the used BBJ costs $32 million - what do you think the upgrades
and infrastructure would cost? (and you'd keep the jet fuel tanks and
be able to switch back and forth if needed)- Hide quoted text -

- Show quoted text -

Brad,

And you claim not to be a master of Black Propaganda. But here you
are, practicing it like a pro.

You'e gotta know that the Space Shuttle ET carries 106 metric tons of
liquid hydrogen in 1,497 cubic meters while I just said that I would
carry 6.3 metric tons of liquid hydrogen in 90 cubic meters - to
maintain the same range - and perhaps double that to 12.6 metric tons
in 180 cubic meters to nearly DOUBLE the range.

Sheez

http://en.wikipedia.org/wiki/Space_Shuttle_external_tank

But here you are, forever stuck within this anti-think-tank of Usenet
naysayland, still poor as hell and going nowhere fast, much less via
hydrogen. What's wrong with this picture.
- Brad Guth
.

Relevant Pages

  • Re: Buying a BBJ and converting it to hydrogen
    ... consuming atmosphere of mostly N2 as it's fuel is technically doable, ... hydrogen tank up top, and a standard A300 interior below. ... metric tons of the stuff on a typical day. ... total volume of 90 cubic meters comes up with 3.8 sq meters. ...
    (sci.energy.hydrogen)
  • Re: Buying a BBJ and converting it to hydrogen
    ... roughly 10% the passenger and freight capacity is a more than likely ... the NOx of regular jet fuel powered varieties. ... Sure does - what about an ADD ON TANK right on top of the 737? ... metric tons of the stuff on a typical day. ...
    (sci.energy.hydrogen)
  • Buying a BBJ and converting it to hydrogen
    ... The jet engine isn't difficult at all. ... Maximum Fuel Capacity 6,875 U.S. gal ... Sure does - what about an ADD ON TANK right on top of the 737? ... metric tons of the stuff on a typical day. ...
    (sci.energy.hydrogen)
  • Re: Buying a BBJ and converting it to hydrogen
    ... the NOx of regular jet fuel powered varieties. ... hydrogen tank up top, and a standard A300 interior below. ... metric tons of the stuff on a typical day. ... total volume of 90 cubic meters comes up with 3.8 sq meters. ...
    (sci.energy.hydrogen)
  • Re: Buying a BBJ and converting it to hydrogen
    ... roughly 10% the passenger and freight capacity is a more than likely ... the NOx of regular jet fuel powered varieties. ... hydrogen tank up top, and a standard A300 interior below. ... metric tons of the stuff on a typical day. ...
    (sci.energy.hydrogen)