Diesel or Petrol engines?

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I know i really shouldnt reply to this thread :rolleyes: but..in a plane its petrol inline 12 cylinders or v12s and v16s are the go or even radials.Diesels are more for your "what is a tank "thread ;)
Yup, the JU86 (especially the High Altitutde Recon version,) did indeed use diesels. Diesels are NOT as affected by air pressure as Petrol engines and they will run on just about anything!

As well the Aero diesels were both well-designed and very efficient.

Fuhrer von Spam Kiwimac
"deisels aren't affected by air pressure"? Try pulling a B-train over the Great Divide without a turbo!

There is quite a difference between hauling a bloody great train over the mountains and taking a plane up to 40 or 50 000 feet. Apart from any other consideration the train's weight is measured in tens, if not thousands, of kilotonnes, while the plane is likely to be in the 5k to 13k range.

Indeed the aero-engine industry has continued to consider and develop diesel aero-engines since the mid 1930's. Diesel's have a better power-to-weight ratio than petrols and, unlike petrol engines, you can run them on just about anything.

FVS Kiwimac
Ya hadda make me do it, did'nya!

From the The Engineer 6 August 1999

The Engineer 6 August 1999

"Diesel in demand"

"Over 50 years since they helped power German bombers in the Blitz, a new generation of diesel aeroengines is set to take to the air. Brian Davis looks at the UK and overseas players competing in this new market"

"Spurred by a move towards cheaper, more environmentally-friendly fuels, two UK firms are leading a revival in diesel engine technology.

The small-but-innovative engineering teams at Wilksch Airmotive and Diesel Air are targeting diesel engines at the home-built kit and light aircraft market. And the international competition is hotting up, with French, German and US firms also researching diesel technology.

Large diesel aero-engines were first developed in Germany in the 1930s, but were superseded by jet engines after the war.

In the light aircraft market, petrol engines have dominated because the Avgas they run on has been relatively cheap. And four-stroke petrol engines have remained popular, despite having a poorer power-to-weight ratio than diesel engines.

However, the diesel/Avtur fuel used by new diesel engines is a third of the price of conventional aviation fuel, and the engines are claimed to be cleaner, as diesel avoids lead emissions while cutting carbon monoxide and hydrocarbons output.

Diesel engines also run lean, with high compression ratios, making them more efficient than petrol engines. Avtur engines do not need priming to start, have no carburettor icing problems, no mixtures to fiddle with, and need less maintenance.

Australian engineer Mark Wilksch, founder of Wilksch Airmotive, learnt to fly at 16. Following spells as an engineer for the Royal Australian Air Force and the Flying Doctor service, he moved to the UK to work with the Arrow Formula One team, later joining Ford's European technical centre to develop petrol injection Systems.

With the help of a private backer and two DTI Smart awards worth £105,000, Wilksch left Ford to start his own company, and set about developing a two-cylinder, 80hp prototype diesel engine. Earlier this month his latest version, a three-cylinder WAM-120 engine, was fitted in Europa kit-built aircraft. It is due to start test flights later this year.

'At the start of the 1990s, many people thought my idea was crazy. Now everybody seems to believe this is the way to go,' says Wilksch. By 2001, 'with the help of a third, £300,000, Smart award, he hopes to secure orders for a family of diesel-powered engines.

Wilksch's two-stroke engine fires twice as often as a four-stroke and is claimed to run smoothly. The close coupling of the turbocharger also offers more efficient energy recovery at all running speeds.

The piston/con rod connection has a spherical joint instead of gudgeon pins, so the piston and rings are free to rotate, reducing wear on the piston.

The engine is inverted in line with integrated oil and cooling systems, and will be equipped with a mechanical blower to sustain idling and low-power settings.

The production version will about 100kg - lighter than rival Lycoming or Continental engines, but with the same power.

Once the engine is proven, Wilksch will apply for Joint Airworthiness Authority certification and a Federal Aviation Administration production licence for the US. He estimates the demand for diesel engines to be 1,000-2,000 a year.

But there are plenty of competitors on the horizon - including Diesel Air, formed in 1997 by David Soul, a Wilksch shareholder who left due to differences in opinion...

...Diesel Air plans to have a prototype DAIR 100 running on a Luscombe Silvaire light aircraft later this year. The engines will be available for aircraft builders next summer.

In Germany, Zoche has been developing a radical diesel engine for about 15 years. In France, Renault Moraine has a joint venture with Socata to develop a four-stroke horizontally-opposed, air-cooled 180-350hp diesel engine to run on Avtur. Flight trials have begun, aiming at certification by 2001.

In the US, Lyoming has bought a diesel engine 'project from Italian company VM, while continental is carrying out a research project with Perkins Technology on a uni-flow, scavenged two-stroke aviation engine. Both companies aim to develop larger engines for two to four-seater aircraft, rather than the 100-200bhp versions Wilksch is concentrating on.

'These are not direct competitors: they are far bigger, and are helping to legitimise the marketplace for diesel engines,' says Wilksch."

From Today's Pilot July 2001

Today?s Pilot July 2001


"Ah, the seemingly endless saga of the diesel aero-engine. For years now we've all been teased with the prospect of a simple, yet powerful and reliable, diesel aero-engine. Such a device (we were told) would have an enormous TBO (possibly 50% longer than comparable petrol-fuelled engines). With a single power lever and no ignition system, these engines would be easier to operate and also very reliable. Furthermore, these wonderful engines would operate on Jet A-1, which is currently around 35 pence a litre as opposed to Avgas, which currently sells for about 94 pence per litre. Jet A-1 is also far more widely available. So where were all these marvellous motors? Well, the answer was actually very simple - their excess weight conspired to preclude their use. Pound for pound and horsepower for horsepower, the petrol-fuelled engine was always going to win.

However, for a variety of reasons, not the least of which is the imminent demise of 100LL Avgas, several diesel aero-engines are now being tested, and Today's Pilot looked at some of the new designs at the AERO show at Friedrichshafen last month. There were a surprisingly large number of diesels at the show, using a wide variety of different configurations. Liquid-cooled two-stroke flat twins, air-cooled two-stroke twin row radials, liquid-cooled two stroke flat fours, air-cooled four stroke flat fours, liquid-cooled in-line fours -even a liquid-cooled Wankel! It seemed that the hour of the diesel aero-engine had finally come.

One of the most interesting engines, as well as one of the few which had actually flown, was the TAE 125. This is a 125hp liquid-cooled, turbo-charged four-cylinder in-line engine adapted from an existing car motor. Frank Thielert, the engine's designer, told Today's Pilot that it had already run for over 5,000 hours on the bench and had been flight-tested in two aircraft - a Valentin Taifun and a Piper PA-28. Although more than 50 hours had been flown on the Taifun, the Piper had only logged 12 hours before the show, though Frank said he was hoping to have 1,500 hours flown on it by the end of the year. This engine, which has been designed to compete with the ubiquitous Lycoming 0-320, certainly looked very impressive on paper, Frank claimed that as the TAE 125 only burned 15 litres per hour of diesel, as opposed to the 33 litres per hour of Avgas burnt by an 0-320 at similar power settings, the direct operating costs would be reduced by 77%. Furthermore, the TBO would be increased from 2,000 hours for the Lycoming to 3,000 hours for the TAE. Other advantages would be single power-lever operation, no loss of power with altitude below 12,000ft and Full Authority Digital Engine Control.

It was also interesting to note that the TAE engine was fractionally lighter than an 0-320. However, the reduction gearbox, which is necessary because of the TAE's relatively high maximum engine speed of 3,800rpm, adds an extra layer of complexity that the direct-drive Lycoming does not have.

An engine which has been generating a lot of interest, but which was not at Friedrichshafen, was the Wilksch Air Motive WAM-120. This very compact engine is a 12Ohp inverted in-line three-cylinder two-stroke, using WAM's CITEC concept. This engine uses a compact exhaust manifold, putting the turbocharger very close to the exhaust ports for efficient exhaust energy recovery. Liquid-cooled and turbocharged, the WAM-120 has been specifically designed for the light (2-4 seat) end of the market and has elicited a considerable amount of interest from kitplane builders.

I spoke with Mark Wilksch during Aerofair, and Mark was very upbeat about the future for diesel aero engines. Indeed, he already has plans for a four cylinder 160hp engine. One of the features I particularly liked about the WAM-120 is that, once it has started, its operation is purely mechanical. Another plus is that the inverted configuration confers good clearance between the propeller and the ground. Wilksch Airmotive's designers have also gone to considerable trouble to produce a complete, integrated package. The WAM-120 will be shipped for £10,000 with complete oil and cooling systems all included. Installation uses WAM's "Parafocal" rear mount system and Mark said that this "should be a doddle on most tractor installations".

The company is also working with a partner on a LongEZ installation which reverts to airframe mounted cooling. WAM has set up a deposit trust fund and has now taken orders from seven countries. Production is booked out well into 2002, and Today's Pilot will be testing the WAM powered Europa later this year.

Other diesel engines seen at AERO were the l00hp Diesel Air DAIR-100, the 3OOhp Zoche radial and the twin-rotor Wankel from KRM. It was interesting to note that Morane-Renault SMA 5R305 obtained European certification just before the show. This is an air-cooled turbocharged four stroke flat-four, which produces 230hp at 2,2OOrpm. With a projected TBO of 3,000 hours, this will clearly be another engine to watch.

Indeed, Cirrus Design Corporation announced during the show that Cirrus is working on an aircraft which will be powered by this engine. Known as the Cirrus SR21tdi, this aircraft is initially being developed exclusively for Cirrus's European customers, and is likely to become Cirrus's flagship product in Europe.

So is the diesel aero-engine finally going to achieve the prominence it has always promised? I believe that, particularly in Europe and probably globally (with the possible exception of America), the answer is 'yes'.

Leaded petrol is definitely on the way out - indeed, in some parts of the world it is already very difficult to find Avgas l00LL. Conversely, Jet A-1 and diesel fuel are both readily available. Although there will certainly still be some Avgas refined, it will be produced in such small quantities that it will undoubtedly be extremely expensive. Will we all be flying diesels in the future? Only time will tell, but the signs look good."

me neither! o and sry for calling you and the lanc right ol' tea leaves... it isnt posted here but my friend asked y i kept signing on and off of msn and i said i was trying to add two british guys and i said u guys were right ol' tea leaves because i didnt know what it meant, but its fun to say!
p.s. if u get an add contact request from [email protected], its me

Reichsmarschall Batista

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