Conserving fuel on 4 engine planes?

[Chief McGee]

Just watching a movie with a 4 engine prop plane running out of fuel over
the ocean. So what would be the best way to conserve fuel. I'm thinking
throttle back all four engines and let them loaf along. Or would you cut
two engines and let two carry the load. Two would have to work harder, but
would they use less fuel then 4? Of course, range becomes more important
then speed. Any opinions?

[kd5sak]

"Chief McGee" > wrote in message
news:JSMNf.1522$oL.225@attbi_s71...
> Just watching a movie with a 4 engine prop plane running out of fuel over
> the ocean. So what would be the best way to conserve fuel. I'm thinking
> throttle back all four engines and let them loaf along. Or would you cut
> two engines and let two carry the load. Two would have to work harder,
> but
> would they use less fuel then 4? Of course, range becomes more important
> then speed. Any opinions?
>

Recently saw a History channel show about Lindbergh and his job as a
civilian
consultant to the Army Air Corps in WWII. His major accomplishment in the
Pacific was in teaching the P-38 pilots how to get remarkably greater range
out of the two engines on that twin engine Fighter. Chances are the same
info he taught might have helped extend the range of the 4 engine plane of
which you speak.

Harold Burton

[Don Hammer]

>Just watching a movie with a 4 engine prop plane running out of fuel over
>the ocean. So what would be the best way to conserve fuel. I'm thinking
>throttle back all four engines and let them loaf along. Or would you cut
>two engines and let two carry the load. Two would have to work harder, but
>would they use less fuel then 4? Of course, range becomes more important
>then speed. Any opinions?
>

Any four engine aircraft I have been involved with has an optimum
speed that gets you the most distance vs fuel burned called Long Range
Cruise (LRC). For instance on the B-707 that speed was M82, the
B-757 is M80. 3 engine LRC on a 707 is also M82, but range would
suffer slightly because of the increased drag with a windmilling
engine and all the trim you had to crank in.

Back in the cold war days, the Navy P-3's would loiter and chase subs
with 1 amd 4 shut down. That got them the most time on station, but I
doubt that helped the range.

[COLIN LAMB]

When it comes to fuel conservation, you should consider whether you want
time aloft or distance covered. The choice determines how you conserve. If
you are going for distance, you must consider the most efficient operation
of the engine along with the winds aloft. If there is a headwind, you will
want to go faster than normal optimum range.

When you run out of fuel in the middle of a big ocean, it is often more than
just knowing how to get 3% better fuel economy.

Colin

[Richard Riley]

Just a wild guess, but I'd think shut down and feather 1 and 4, drop to
50 feet or so to get in ground effect, throttle back to best L/D and
lean untill 100 degrees past peak or the engine will barely keep
running, whichever comes first

[Nathan Young]

On Fri, 03 Mar 2006 02:38:22 GMT, "kd5sak" >
wrote:

>
>"Chief McGee" > wrote in message
>news:JSMNf.1522$oL.225@attbi_s71...
>> Just watching a movie with a 4 engine prop plane running out of fuel over
>> the ocean. So what would be the best way to conserve fuel. I'm thinking
>> throttle back all four engines and let them loaf along. Or would you cut
>> two engines and let two carry the load. Two would have to work harder,
>> but
>> would they use less fuel then 4? Of course, range becomes more important
>> then speed. Any opinions?
>>
>
>Recently saw a History channel show about Lindbergh and his job as a
>civilian
>consultant to the Army Air Corps in WWII. His major accomplishment in the
>Pacific was in teaching the P-38 pilots how to get remarkably greater range
>out of the two engines on that twin engine Fighter. Chances are the same
>info he taught might have helped extend the range of the 4 engine plane of
>which you speak.

I believe this was using a very high MP + a low RPM setting?

[Al]

"Chief McGee" > wrote in message
news:JSMNf.1522$oL.225@attbi_s71...
> Just watching a movie with a 4 engine prop plane running out of fuel over
> the ocean. So what would be the best way to conserve fuel. I'm thinking
> throttle back all four engines and let them loaf along. Or would you cut
> two engines and let two carry the load. Two would have to work harder,
> but
> would they use less fuel then 4? Of course, range becomes more important
> then speed. Any opinions?
>


Just ask "Old Whistling Dan"...

If it is a reciprocating engine, you'll do better at a low RPM, adjust MP to
hold your best L/D(or your best glide speed), and lean it all you can
without detonation.(Make the most out of each "piston push", intake each
cylinder as few times as possible, best L/D=most efficient airspeed, see
Lindberg)

If it was a Turbo charged engine, you'd do better up high, up to the mid
20's.(high true airspeed)

It you are Eastbound, you'd usually do better up high, up to the mid
30's(Tailwinds, use a slightly lower glide speed, aim for best endurance to
take advantage of the wind)

In most aircraft, Keep them all turning. After you've ditched all the weight
you can, close all the cowl flaps, vents, doors & windows. Get rid of
external stores. Think clean thoughts.

Move the CG slightly aft.(Won't help much, but what the hey. It reduces
elevator download & drag)

Don't run windshield wipers and reduce the electrical load.(wipers produce
drag, electrical load eats horsepower)

If you're John Wayne, coming from Hawaii to Oakland, in the High and the
Mighty, don't worry, it will work out.

Al (US National Economy Record Holder)

[kd5sak]

"Nathan Young" > wrote in message
...
> On Fri, 03 Mar 2006 02:38:22 GMT, "kd5sak" >
> wrote:
>
>>
>>"Chief McGee" > wrote in message
>>news:JSMNf.1522$oL.225@attbi_s71...
>>Recently saw a History channel show about Lindbergh and his job as a
>>civilian
>>consultant to the Army Air Corps in WWII. His major accomplishment in the
>>Pacific was in teaching the P-38 pilots how to get remarkably greater
>>range
>>out of the two engines on that twin engine Fighter. Chances are the same
>>info he taught might have helped extend the range of the 4 engine plane of
>>which you speak.
>
> I believe this was using a very high MP + a low RPM setting?

Don't remember the details, not being a pilot myself, but remember that the
pilots were taught to use certain engine and fuel settings on peril of
destroying their engines. Lindbergh taught them to use different settings
and supposedly the squadron tried his methods for a period of time on a
single plane, tore down the engines and found they had suffered no excessive
wear. The entire squadron then used his settings and this alllowed
the P-38s a much extended range. I did a little net search after writing the
previous sentence. The URL below gives details on a 30% or better fuel range
resulting from Lindberghs advice.

http://p-38online.com/lindy.html

Harold
KD5SAK