Kachapol - -
Diesel engine use in aircraft is a current design issue, as
manufacturers seek new designs that will eliminate the continued use
of low-lead fuels. Switching to diesel fuel will allow general
aviation aircraft to use commonly available diesel fuel instead of
avgas, which is an increasingly small percentage of the refined fuel
market. In remote places avgas is virtually impossible to find,
though diesel fuel or Jet A may be readily available.
More benefits than cost-savings and the elimination of lead come from
the use of diesel designs. Engineers also hope to increase
time-before-overhaul (TBO), simplify the engine, move to single-lever
controls from complex leaning systems, and give a power plant that
runs smoother, as this article in the Racine (WI) Journal-Times notes:
DeltaHawk Engines
"Engine research puts Racine on aviation map "(Jan. 11, 2001)
http://www.deltahawkengines.com/journa00.htm
Diesels also eliminate some of the design problems of gasoline-powered
piston engines, including magneto systems, vapor-lock problems,
carburetor icing, high piston and turbine inlet temperatures, and use
of a highly-explosive gasoline.
Diesel engine use isn't new in aircraft. In fact, it was pioneered by
Zeppelin in airships after World War I. But subsequent years
developed lightweight normally aspirated piston engines, as well as
turbocharged and supercharged engines for use from FL150 to FL290:
Google Answers
"Early Airship Design & Development" (Omnivorous-GA, May 10, 2003)
http://answers.google.com/answers/main?cmd=threadview&id=201580
Zoche makes reference to older Junkers, Guiberson, Clerget, Fiat,
Rolls-Royce and Packard designs for diesel aircraft engines on its
home page, which has a variety of design information:
Zoche Aero-Diesels
Home page
http://www.zoche.de/
The Aircraft Owners & Pilots Association (AOPA) and Avweb, two popular
aviation publications identify at least 5 companies which have done
diesel prototypes:
AOPA Pilot Magazine
"Horsepower of a Different Color" (August, 2000)
http://www.aopa.org/pilot/features/future0008.html
Avweb
"GAP Engine Update" (July 27, 2000)
http://www.avweb.com/news/reviews/182838-1.html
THIELERT AIRCRAFT ENGINES
==========================
Thielert's TAE 125 engine is now called the Centurion 1.7, a 1.7-liter
diesel design that produces 135hsp. It's probably the most-advanced
of the diesel designs, being certified in Europe since May, 2002.
Sold in the U.S. by Superior, the Centurion 1.7 is certified for use
in the Cessna 172. It's also in Diamond Aircraft Industries DA40, a
single engine design, and in the twin DA42 - - which is still under
development:
Thielert Aircraft Engines
"Centurion 1.7" (2002)
http://www.thielert.com/en/index.html
More technical descriptions of the Centurion 1.7 are available here.
Note that Centurion is also developing a higher-performance version of
the engine to compete against the gasoline-powered IO-550:
Centurion Engines
"Technical Specifications"
http://www.centurion-engines.com/c17/c17_data.htm
Diamond test-flew the DA40 several years ago with the Centurion 1.7
diesel but plans to offer the aircraft only in the European market:
Diamond Aircraft
"Diamond Aircraft flies diesel equipped DA40" (November, 2001)
http://www.diamondair.com/contentc/prdiesel.htm
However, the new Diamond twin-engine aircraft, still in certification,
will use a pair of Centurion engines. The aircraft is planned for
2004 deliveries:
Diamond Aircraft
"Diamond DA42 TwinStar first flight" (December 12, 2002)
http://www.diamondair.com/contentc/TwinFlies.htm
DELTAHAWK ENGINES
===================
This company in Racine, WI has 2 models planned, a 160-hsp and 200-hsp
V-4 turbocharged engine with the following characteristics.
DeltaHawk's initial work is with a Velocity (pusher) design, though
the company is developing an aluminum block version of the same engine
for unmanned aerial vehicles. These engines are water-cooled :
DeltaHawk Engines
"V-4 Aviation Turbo Diesel Specifications" (2001)
http://www.deltahawkengines.com/contents.htm
"DeltaHawk's First Flight - Finally !" (May, 2003)
http://www.deltahawkengines.com/HomePagePhoto.html
ZOCHE AERO-DIESELS
====================
This developer in Munich, Germany has 2-cylinder, 4-cylinder and
8-cylinder designs with the largest engine being a radial design. The
use of the radial plane makes the engines much shorter than standard
aircraft designs. The simplified design also has about half the
weight of current aircraft engines. Zoche's engines are air-cooled:
Zoche Aero-Diesels
"Specifications" (undated)
http://www.zoche.de/specs.html
One of the design vehicles for the Zoche diesels is the Virginia
Tech's advanced concept design called Venture. It's a single-engine
aircraft using composite structure:
Virginia Tech
"AGATE Design" (undated)
http://www.aoe.vt.edu/design/venture/intro.html
The university's design team was attracted to the Zoche engines for
all of the design reasons, but especially weight and performance,
while providing better safety capabilities:
AGATE Design
"Propulsion"
http://www.aoe.vt.edu/design/venture/prop.html
MORANE RENAULT
=================
In the late 1990s, this joint venture of Renault and an Aerospatiale
Matra subsidiary produced a 180hsp engine that was put into testing in
the TB-20 Trinidad. It was anticipated that the engine would be
approved and into production in 2001:
Society of Aerospace Engineers
"New Diesels for GA Aircraft"
http://www.sae.org/aeromag/techupdate/10-1999/09.htm
However, since then no production has occurred nor has the company
done any updates on the status of the program.
LYCOMING DETROIT-DIESEL
========================
In 1998, Lycoming and Detroit Diesel had announced a joint venture to
develop a diesel engine for aircraft use:
Detroit Diesel
"Textron Lycoming, Detroit Diesel to Develop Aero Engine" (July 31,
1998)
http://www.detroitdiesel.com/public/corp/pr073198.asp
There has been nothing from Lycoming to update that program:
Textron Lycoming
Home page
http://www.lycoming.textron.com/
TELEDYNE CONTINENTAL MOTORS (TCM)
====================================
According to Avweb, the General Aviation Propulsion (GAP) engine was
being developed in 2000 under a research contract from NASA. The
test-bed for this engine is a CessnA 337 Skymaster, in which the
engine is being mounted in the front of the push-pull twin, with a
conventional IO-360 being used as the rear engine.
However, according to this report, Teledyne has recently killed this
program in favor of a joint venture with Honda to develop engines to
run on standard auto gas:
Diesel Air Newsletter
"Contact" (April 23, 2003)
http://www.dieselair.com/
Google search strategy:
Avweb + diesel
AOPA + diesel
Google is best used here to refine the search, using each of the
manufacturers' names to seek out aircraft designs that have been
announced, such as :
"Zoche Aero-Diesels" or "Morane Renault"
This search and description doesn't reach 2,000 words but provides
detailed technical specifications for active diesel aircraft engine
programs to allow you to extract the information that you need for
description and features.
If any portion of this needs clarification, please let me know before
rating this answer.
Best regards,
Omnivorous-GA |
Clarification of Answer by
omnivorous-ga
on
12 Jun 2003 09:36 PDT
Kachapol - -
The design of gasoline-powered and diesel reciprocating engines is so
different that its sometimes difficult to chose the right engines to
compare. For example, Centurion has certified its engine as a
replacement for the O-320 in the Cessna 172 and notes:
"How can a 135HP engine effectively replace my 160HP Lycoming?
A: The static thrust, which is the force generated by the engine to
accelerate it forward from standing, of the Centurion 1.7 is greater
than the static thrust of the Lycoming O320 and equal to the Lycoming
O360."
Centurion Engines
"FAQ" (undated)
http://www.centurion-engines.com/c17/c17_faq_en.htm
Its made worse by the terrible Textron Lycoming website, which has
only cursory information on the 320 and 360 series engines. Though
Lycoming has long has an excellent printed "Piston Engine Selection
Guide," the web version is short on details:
Textron Lycoming
"Piston Engine Selection Guide" (undated)
http://www.lycoming.textron.com/main.jsp?bodyPage=/productSales/engineSelectionGuide/index.html
Should you choose to use Continental engines, even though horsepower
levels dont line up well, youll find much more detailed
specifications, such as these for the 210hsp IO-360:
Teledyne Continental Motors
"IO360 Specifications" (undated)
http://www.tcmlink.com/EngSpecSheetDocs/IO360C.doc
But well do the best that we can by creating a comparison chart for
an IO-360 and the Centurion 1.7:
GASOLINE POWERED IO-320
# Cylinders: 4
Type: 4-stroke
Compression ratio: between 7:1 and 8.5:1
RPM: 2700 max
Power: 160 hsp
Fuel: 100 octane low-lead
Fuel consumption (cruise): 8.5 gph
Ignition system: dual magneto
Carburetion: carburted or fuel-injected
Cooling: air
Turbocharging: NA
Price: $21,500; $26,000 fuel-injected (pricing from VanBortel
Airpower)
TBO: 2,000 hour
Direct drive: yes
Accessories: alternator, starter, vacuum pump
Height: 22.99"
Width: 32.24"
Length: 29.56"
Weight: 256 lbs. (without prop governor)
Other information: long production life with good reliability; capable
of low-cost overhaul
DIESEL CENTURION 1.7
# Cylinders: 4
Type: 4-stroke
Compression ratio: NA (not available)
RPM: 3900
Power: 135 hsp
Fuel: diesel or Jet A
Fuel consumption (cruise): 4.5 gph
Ignition system: diesel (glow plug)
Carburetion: fuel-injected
Cooling: liquid
Turbocharging: standard
Price: $19,500 Euros
TBO: not capable of overhaul; time before replacement (TBR) is 2400
hours
Direct drive: no: uses a gear reduction to achieve 2300 RPM (takoff
maximum) at prop
Accessories: FADEC, alternator, starter, turbocharger, vacuum pump,
prop governor
Height: NA
Width: NA
Length: NA
Weight: 295 lbs. (with prop governor)
Other information:
· company estimates that total installed weight is only 6.5-9 lbs.
more than a full Lycoming O320 installation
· engine operates at higher RPM but is not constantly variable in
power, as with normal gasoline engine. Centurion believes that wear
will be lower
· use of electronic engine control (FADEC) eliminates use of mixture
controls by pilot; reduces danger of damage from over-leaning (and
pre-ignition) or over-boosting
· significantly lower cylinder head temperatures
· turbocharging provides significantly better performance than the
normally-aspirated engines at higher altitudes and high density
altitudes
· FADEC system provides electronic history for engine analysis
· though the company claims cold starts wont be a problem, they often
are with diesel systems
· vapor lock and hot start problems should be reduced
Finally, note that many of the key differences between diesel and
gasoline engines (safety, availability of fuel) should really be
re-emphasized here.
Best regards,
Omnivorous-GA
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