Aerotow with Diesel engine?

"Z Goudie" wrote in message
...
Bill Daniels wrote:

Reading the Diesel Air Ltd. site about the ducted fan
dirigible
application, they say that they get 8 pounds of static
thrust for each HP.
If 100 HP = 800 pounds of thrust, that stacks up pretty
well against a 235
Pawnee that only produces about 390 pounds of thrust.
That would be good
for avoiding wing dropping.

Jings, crivvens, I can just see the FAA, CAA or JAR
falling all over themselves to approve a ducted fan
for an existing airframe.

The new Sport Light Aircraft regulations (US) have specific language
permitting experimental glider tugs. Nobody said anything about fitting a
ducted fan to an existing airframe.

A diesel engine of a given horsepower with a propeller
on it will produce the same thrust as similar power
petrol (gas, steam) one.

Nope. A Bell 47 helicopter rotor turning 300 RPM will produce more than
2450 pounds of static thrust with just 266 HP. The fact that it flies
proves that.

Diesels produce their power at low RPM's. A slower turning propeller that
can absorb the same HP will produce more thrust. A ducted fan will produce
still more thrust per HP at low airspeeds.

It will, if turbo charged (another complication), produce
sea level power up to a considerable height but I don't
think that's a major problem for near sea level dwellers.

All 2-stroke diesels are supercharged - else they won't run.


As far as I can see what's driving the production of
diesel engines in Europe is the low/no tax on diesel
or jet fuel. How long will it take the fiscal authorities
to latch on to that one I wonder?

Europe has been using diesel fuel for a long time. Raising taxes on
agricultural diesel will be a political hot potato. General Aviation fuel
use is tiny compared to road use.

Bill Daniels

The only fuel that I am confident I will be able to find for
aircraft in the coming decades is Jet fuel. If I purchased a
certified aircraft for long term use, it would be powered by this,
or be an experimental (where I could use whatever I want)

In California, the abolishment of MTBE made all the autogas
STCs of aircraft invalid (the new ethanol gas isn't covered by
the STC).

I don't have confidence that 100LL will be available in the near future.
80 has already almost disappeared from general aviation.

Diesel? I'd be surprised to see that in 200 California airports
within the next 10 years.

In article ,
Stefan wrote:
Bill Daniels wrote:

They feel their engine would make a near
perfect tug engine.

Surprize! :-)

A rumor is ...

So much for "practical information".

Diesels make power at lower RPM's than a spark ignition engine so they can
use larger, quieter, more efficient propellers.

There isn't a requirement anywhere that propellers have to be direct
driven. Actually, the only diesel flying today uses a gearbox.

(Sorry for my unfair quoting, but I couldn't resist.)

Stefan



--

------------+
Mark J. Boyd

Mark James Boyd wrote:
The only fuel that I am confident I will be able to find for
aircraft in the coming decades is Jet fuel.ral aviation.
[...]
Diesel? I'd be surprised to see that in 200 California airports
within the next 10 years.

Diesel engines in aircraft run on Jet A1.

Christian 8-)

At 21:48 21 October 2004, Bill Daniels wrote:

Nope. A Bell 47 helicopter rotor turning 300 RPM will
produce more than
2450 pounds of static thrust with just 266 HP. The
fact that it flies
proves that.

Ah, so we're going to need very long undercarriage
legs then?

"Z Goudie" wrote in message
...
At 21:48 21 October 2004, Bill Daniels wrote:

Nope. A Bell 47 helicopter rotor turning 300 RPM will
produce more than
2450 pounds of static thrust with just 266 HP. The
fact that it flies
proves that.

Ah, so we're going to need very long undercarriage
legs then?

It wouldn't be hard to design an airframe that could use a 3-4 meter prop.
That would do a lot for low speed thrust and lower noise.

Bill Daniels

At 13:36 22 October 2004, Bill Daniels wrote

It wouldn't be hard to design an airframe that could
use a 3-4 meter prop.
That would do a lot for low speed thrust and lower
noise

Back to the reduction gearing scenario then?

(Mark James Boyd) writes:

Diesel? I'd be surprised to see that in 200 California airports
within the next 10 years.

Diesel has a problem with wax precipitation at low temps, so most are
set up to use A1 as the standard fuel.

A diesel recently flew St Johns to Portugal at OVER 27 NM/gal!

--
Paul Repacholi 1 Crescent Rd.,
+61 (08) 9257-1001 Kalamunda.
West Australia 6076
comp.os.vms,- The Older, Grumpier Slashdot
Raw, Cooked or Well-done, it's all half baked.
EPIC, The Architecture of the future, always has been, always will be.

Now that Diesel is hovering in the $2.50 (U.S.) range, what would be the big
savings?? The Diesel engines I've seen on the market for Aircraft use cost
WAY more than gasoline engines...I'd be surprised if we actually settled on
the fuel cost being anywhere near the biggest cost driver in the actual cost
of a tow...

My DG-400 costs two liters of unleaded per launch to 2,500 ft agl....not too
bad when you cost it all out. Acquisition cost of the tug, depreciation of
the asset, Insurance for the tug, annual for the tug, fuel, maintenance,tie
down/hangar, interest if there's a loan Engine reserves...I know for a fact
my Cessna 180 costs WAY more to launch a sailplane on an annual basis than
does the DG...maybe we just need a bunch more self launchers??


( wincing...thinking of the can of worms this comment will open )


Steve.

"Steve Hill" wrote in message
...
Now that Diesel is hovering in the $2.50 (U.S.) range, what would be the
big
savings?? The Diesel engines I've seen on the market for Aircraft use cost
WAY more than gasoline engines...I'd be surprised if we actually settled
on
the fuel cost being anywhere near the biggest cost driver in the actual
cost
of a tow...

My DG-400 costs two liters of unleaded per launch to 2,500 ft agl....not
too
bad when you cost it all out. Acquisition cost of the tug, depreciation of
the asset, Insurance for the tug, annual for the tug, fuel,
maintenance,tie
down/hangar, interest if there's a loan Engine reserves...I know for a
fact
my Cessna 180 costs WAY more to launch a sailplane on an annual basis than
does the DG...maybe we just need a bunch more self launchers??


( wincing...thinking of the can of worms this comment will open )


Steve.

I don't disagree about motorgliders but there will always be a lot of pure
gliders around that need launching. Diesels will produce the same power on
roughly 1/3 less fuel and that fuel could be un-taxed agri-diesel in the
case of a warm weather glider tug. That would be a large but not
overwhelming savings. If diesels get as popular as most aviation experts
suggest, the availability of avgas and spark ignition engine parts and
repair may eventually be a greater concern.

A typical 180 HP Lycoming O-360 will burn $60,000 worth of avgas to get it
to a 2000 Hr TBO. A 260 HP Lyc O-540 will burn close to $100,000 worth of
avgas in 2000 hours. Engine overhauls are also a big cost but less per hour
than fuel. Any way you look at it, a tow plane is a black hole sucking in
money.

If you really want to save fuel, think winch launch. That takes about 1/2
liter of diesel to launch a typical glider. That could easily be vegetable
oil. If you are lucky enough to be able to use an electric winch, a launch
will use about 1KW Hr. of energy at about $.05. Add to the fuel savings the
fact that you don't have to deal with the FAA trying to get a Tost hook
installed on a Pawnee.

Bill Daniels

The Australians have an Autotug project that uses a 6 cylinder car engine
,parts available
everywhere overhauls 3-5k US replacement engines available everywhere.
the scuttlebutt was the main problems were making the engine mounts and
ducting
cooling air onto the radiator.I believe it is approaching a 1000hours .
There is a Swedish project using a volvo car engine with similar results ,
The way to go is to get the dollar gobbler(the engine ) changed to a mass
produced
item, that is the car market ,millions of engines instead of hundreds
gary
"Steve Hill" wrote in message
...
Now that Diesel is hovering in the $2.50 (U.S.) range, what would be the
big
savings?? The Diesel engines I've seen on the market for Aircraft use cost
WAY more than gasoline engines...I'd be surprised if we actually settled
on
the fuel cost being anywhere near the biggest cost driver in the actual
cost
of a tow...

My DG-400 costs two liters of unleaded per launch to 2,500 ft agl....not
too
bad when you cost it all out. Acquisition cost of the tug, depreciation of
the asset, Insurance for the tug, annual for the tug, fuel,
maintenance,tie
down/hangar, interest if there's a loan Engine reserves...I know for a
fact
my Cessna 180 costs WAY more to launch a sailplane on an annual basis than
does the DG...maybe we just need a bunch more self launchers??


( wincing...thinking of the can of worms this comment will open )


Steve.