Engine on Global Flyer

[Brent]

They're saying the Global Flyer's jet engine burns 102 pounds of fuel an
hour. If that kind of fuel weighs in at 6 pounds per gallon, that's
about 17 gallons an hour, or roughly double what I burn in the little
Cherokees I fly. Then again, the jet propelled the Flyer about 2 times
as fast with a max weight some 4 times greater (again, compared to a
Cherokee). It seems to me that somebody might by in the market for a
plane with characteristics like that...but am I missing something?

--Brent

[Kyle Boatright]

"Brent" <""b b i g l e r \"@ y a h o o . c o m"> wrote in message
...
> They're saying the Global Flyer's jet engine burns 102 pounds of fuel an
> hour. If that kind of fuel weighs in at 6 pounds per gallon, that's about
> 17 gallons an hour, or roughly double what I burn in the little Cherokees
> I fly. Then again, the jet propelled the Flyer about 2 times as fast with
> a max weight some 4 times greater (again, compared to a Cherokee). It
> seems to me that somebody might by in the market for a plane with
> characteristics like that...but am I missing something?
>
> --Brent

First, that 102 pounds per hour is under a very special set of
circumstances - less than full thrust, and at fairly high altitude - 45,000'
or so. Jets are much more efficient up there. IIRC, the fuel burn was
several times that during the early part of the flight.

As to there being a market for a plane like that, I'm sure there would be
one IF the aircraft didn't come with all of the compromises that give the
Global Flyer its tremendous performance. What limitations, you ask? 100+
foot wingspan isn't very ramp friendly at many small fields. Razor thin
structural margins which would make moderate turbulence a chancey
proposition. The light wing loading and slick design mean the aircraft has
*special* needs in the landing pattern - you saw the drag chutes? Also, the
light weight and large physical size probably make the airplane a real
handful in crosswinds.

There are plenty of other compromises that were made to achieve the GF's
performance, and most of 'em work against using the aircraft for practical
transportation...

KB

[John A. Weeks III]

In article >,
Brent <""b b i g l e r \"@ y a h o o . c o m"> wrote:

> They're saying the Global Flyer's jet engine burns 102 pounds of fuel an
> hour. If that kind of fuel weighs in at 6 pounds per gallon, that's
> about 17 gallons an hour, or roughly double what I burn in the little
> Cherokees I fly. Then again, the jet propelled the Flyer about 2 times
> as fast with a max weight some 4 times greater (again, compared to a
> Cherokee). It seems to me that somebody might by in the market for a
> plane with characteristics like that...but am I missing something?

And look at the altitude they got out of that aircraft. They
were consistently in the 40,000 foot range.

-john-

--
================================================== ====================
John A. Weeks III 952-432-2708
Newave Communications http://www.johnweeks.com
================================================== ====================

[Joerg]

Hello Kyle,

>There are plenty of other compromises that were made to achieve the GF's
>performance, and most of 'em work against using the aircraft for practical
>transportation...
>
>

Also, it seems that the pilot seat in the Global Flyer must feel like
sitting in a huge jet fuel tank. Not for the faint of heart. But then
again, landing in one of these would certainly turn some heads.

Regards, Joerg

http://www.analogconsultants.com

[RST Engineering]

What in the hell don't you understand about the achievements of
"experimental" aircraft"? Why do you think that we do what we do and then
release our results to the airplane building world?

Jim



"Brent" <""b b i g l e r \"@ y a h o o . c o m"> wrote in message
...
> They're saying the Global Flyer's jet engine burns 102 pounds of fuel an
> hour. If that kind of fuel weighs in at 6 pounds per gallon, that's about
> 17 gallons an hour, or roughly double what I burn in the little Cherokees
> I fly. Then again, the jet propelled the Flyer about 2 times as fast with
> a max weight some 4 times greater (again, compared to a Cherokee). It
> seems to me that somebody might by in the market for a plane with
> characteristics like that...but am I missing something?
>
> --Brent

[David Cartwright]

"Joerg" > wrote in message
m...
> Also, it seems that the pilot seat in the Global Flyer must feel like
> sitting in a huge jet fuel tank. Not for the faint of heart. But then
> again, landing in one of these would certainly turn some heads.

Although the Global Flyer took this concept to extremes, one must remember
that sitting in the average airliner isn't all that far from sitting in a
big fuel tank. The wings are full of it, not to mention various other tanks!
I guess people just don't think about that too much, particularly the
nervous flyers :-)

D.

[Joerg]

Hello David,

>Although the Global Flyer took this concept to extremes, one must remember
>that sitting in the average airliner isn't all that far from sitting in a
>big fuel tank. The wings are full of it, not to mention various other tanks!
>I guess people just don't think about that too much, particularly the
>nervous flyers :-)
>
>

That is true. Even in a regular pickup truck you may be literally
sitting above 40 Gallons of gasoline. One side impact can send that off
into a huge blaze. With nervous flyers it might be best not to talk
about this stuff when sitting next to them. They'd only become more nervous.

Then there are a couple huge engines hanging under the fuel filled
wings. And occasionally one of these goes kaputt. That happened when I
was a passenger on a flight while still over the atlantic, leaving only
one engine to fly on. I believe that the maintenance crew also had to
massage all those clenched armrests back into shape after the landing.
But at least nobody freaked out and despite the uneven thrust the pilot
almost made the landing a perfect greaser. That must have been a white
knuckle event.

Regards, Joerg

http://www.analogconsultants.com

[David Cartwright]

"Joerg" > wrote in message
om...
> Then there are a couple huge engines hanging under the fuel filled wings.
> And occasionally one of these goes kaputt. That happened when I was a
> passenger on a flight while still over the atlantic, leaving only one
> engine to fly on. I believe that the maintenance crew also had to massage
> all those clenched armrests back into shape after the landing. But at
> least nobody freaked out and despite the uneven thrust the pilot almost
> made the landing a perfect greaser. That must have been a white knuckle
> event.

According to a friend of mine who used to fly helicopters to oil rigs, it's
not exactly a white knuckle ride, but there is always a bit of a nagging
thought in the mind of the pilots along the lines of "Unless we're 100% sure
why that engine broke, we can't be sure the other one won't" and so it's
always a relief when you get it on the ground. My friend had a gearbox break
one day, but there were two engines and two gearboxes, and the second one
worked fine and the flight went off safely.

You can't be sure, after all, that whatever caused the fault in one engine
won't do so in another. I remember reading of an incident in a three-engine
aircraft (DC-10?) where a mechanic changed the magnetic chip detectors
(little screw-in plugs that attract particles of metal that have worn off
the engine so you can analyse them) and replaced them with new ones that
didn't have their rubber seals fitted. So all three engines ran low on oil
some way into the flight. Initially they thought there was a spurious oil
leak (ruptured/worn pipe or whatever) in the engine that failed first, only
to see the oil pressure drop on the other two first!

D.

[Joerg]

Hello David,

> According to a friend of mine who used to fly helicopters to oil rigs, it's
> not exactly a white knuckle ride, but there is always a bit of a nagging
> thought in the mind of the pilots along the lines of "Unless we're 100% sure
> why that engine broke, we can't be sure the other one won't" and so it's
> always a relief when you get it on the ground. My friend had a gearbox break
> one day, but there were two engines and two gearboxes, and the second one
> worked fine and the flight went off safely.

Some of these oil rig flights are done with pretty old equipment. I had
been on old Bell Seaking helicopters (as a passenger going to a rig).
About 200 miles or so across the North Sea. We had to don survival suits
and one of the older folks said there is a very good reason for that. He
had gone down once and it took a while until rescue came.

Helicopters are sensitive things. When something would go wrong with the
rotor it may not be recoverable. We had one go down about 1/2 mile from
here last year and unfortunately that one was fatal. I believe a bolt
had come off the rotor assy so there probably was nothing the pilot
could have done.

> You can't be sure, after all, that whatever caused the fault in one engine
> won't do so in another. I remember reading of an incident in a three-engine
> aircraft (DC-10?) where a mechanic changed the magnetic chip detectors
> (little screw-in plugs that attract particles of metal that have worn off
> the engine so you can analyse them) and replaced them with new ones that
> didn't have their rubber seals fitted. So all three engines ran low on oil
> some way into the flight. Initially they thought there was a spurious oil
> leak (ruptured/worn pipe or whatever) in the engine that failed first, only
> to see the oil pressure drop on the other two first!

That is scary. I bet the first time a crew experienced a flame-out
because the Concorde flew by got white knuckles, too. What I read was
that it affected all the engines.

I remember that we got some serious attention when landing in Franfurt
on one engine. All the fire trucks and ambulances they could muster were
seen on the ground, lights flashing and all. They cleared the whole
airspace and that alone was an unusual sight. It wasn't too scary for me
because I used to parachute. That's where you have to stick the landing
no matter what. No engines...

Regards, Joerg

http://www.analogconsultants.com

[David Cartwright]

"Joerg" > wrote in message
om...
> Helicopters are sensitive things. When something would go wrong with the
> rotor it may not be recoverable. We had one go down about 1/2 mile from
> here last year and unfortunately that one was fatal. I believe a bolt had
> come off the rotor assy so there probably was nothing the pilot could have
> done.

There was one in the North Sea not so long ago, where a manufacturing fault
in a blade was exacerbated by a lightning strike, and failed sometime later
in flight. The aircraft was based at my local airport.

> That is scary. I bet the first time a crew experienced a flame-out because
> the Concorde flew by got white knuckles, too. What I read was that it
> affected all the engines.

There was a BA 747 that lost all four engines in a cloud of volcanic ash.
The captain (Eric Moody, I think his name was) was quoted as telling the
passengers something along the lines of: "All four engines have stopped, but
rest assured we're doing our damndest to get them going again". They
descended from cruise altitude in a glide, assuming they'd have to ditch,
and when they popped out of the ash cloud at about 12,000 feet, the engines
spooled up one by one (they'd been left in auto-start mode) and they limped
into a nearby airport. The engines were all knackered thanks to being
shotblasted by the ash (and the windscreen was almost opaque) but provided
enough power that they got away with it.

> I remember that we got some serious attention when landing in Franfurt on
> one engine. All the fire trucks and ambulances they could muster were seen
> on the ground, lights flashing and all. They cleared the whole airspace
> and that alone was an unusual sight. It wasn't too scary for me because I
> used to parachute. That's where you have to stick the landing no matter
> what. No engines...

Well, there's no harm in erring on the side of caution. I remember when a
club at my airport ran a Jet Provost, and the pilot called to report smoke
in the cockpit. Flashing lights, immediate clearance to land however he
wanted on whatever he wanted, everything else in the area told to bugger off
for a while or orbit where they were, you name it. Turned out everything was
fine and it was actually a tiny fluid leak onto a hot pipe, but if the
controller gives you unconditional free rein, it's one less thing to worry
about.

D.

[David Lesher]

"David Cartwright" > writes:


>You can't be sure, after all, that whatever caused the fault in one engine
>won't do so in another. I remember reading of an incident in a three-engine
>aircraft (DC-10?) where a mechanic changed the magnetic chip detectors
>(little screw-in plugs that attract particles of metal that have worn off
>the engine so you can analyse them) and replaced them with new ones that
>didn't have their rubber seals fitted. So all three engines ran low on oil
>some way into the flight. Initially they thought there was a spurious oil
>leak (ruptured/worn pipe or whatever) in the engine that failed first, only
>to see the oil pressure drop on the other two first!

I think it was an L-1011 belonging to National. It made it to Miami Beach,
or almost...

As a result, ETOPS has strict segregation rules. No mechanic works on
both engines, etc.
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