Single rotor turbo diesel rotary

[Geoff_H]

My preferences are for gas turbines.  Simple design, very light for the power output if compression ratio is high.  With metal 3d printing the number of parts could be reduced to very few.  60%efficiency has been obtained with high temperature turbine blades.  They can run on virtually any fuel.  Even coal!!!!! On India a gas turbine station was built using coal, well it made coal gas first, fed that to a bank of gas turbines then burner the coal char in a fluidised bed boiler they generated using steam turbines.

 

A small gas turbine with high efficiency would be either very heavy or very expensive.  But I would love to power my project with one.

 

You can also get two stroke engines that run on diesel with low pressure injection.  Light weight high output.  Not sure of the efficiency

 

 

[turboplanner]

My preferences are for gas turbines.  Simple design, very light for the power output if compression ratio is high.  With metal 3d printing the number of parts could be reduced to very few.  60%efficiency has been obtained with high temperature turbine blades.  They can run on virtually any fuel.  Even coal!!!!! On India a gas turbine station was built using coal, well it made coal gas first, fed that to a bank of gas turbines then burner the coal char in a fluidised bed boiler they generated using steam turbines.

 

A small gas turbine with high efficiency would be either very heavy or very expensive.  But I would love to power my project with one.

 

You can also get two stroke engines that run on diesel with low pressure injection.  Light weight high output.  Not sure of the efficiency

 

12 hp turbo prop RC engine for sale today at $5000.00. Wonder what is would cost to scale that up.

 

 

[facthunter]

Been plenty of successful diesel radials and also the Junkers JUMO series Long range engines. Also ZOD and Packard. (Radials) Nev

 

 

[Geoff_H]

A scaled up version could be quite cheap.  But it is very inefficient.  You could expect fuel consumption to be many times what a Rotax would burn for the same kw.  

 

Efficiency depends upon the compression ratio, here I expect about 4:1, and the turbine inlet temperature TIT.  The higher temperatures that your blades could take the more efficient.  I expect that a turbo prop would be many orders of magnitude higher in cost.  

 

 

[facthunter]

If you are referring to the  Wankel they usually come in at a bit above a two stroke for specific fuel consumption. They can be supercharged very effectively but you can probably not expect a better fuel/power figure. For a sports plane does it matter that much? I don't think it does. Nev

 

 

[Geoff_H]

Sorry Nev, I was replying to the radio controlled turbo

 

 

[onetrack]

Turbo, I take issue with some of your statements;

 

1. "Peak Oil" is a furphy that is long dead and buried. Oil reserves are being expanded faster than we are using oil. Places such as Saudi Arabia have long been spoken of as their oil wells "running dry".

 

The truth is, Saudi Arabia has had to restrict oil production to keep oil prices inflated to levels where they can afford to buy more gold-plated Mercedes and Ferraris.

 

2. There is no such thing as "Lithium Propane". LPG stands for Liquified Petroleum Gas. The gas is actually a liquid under low pressure in LPG tanks, and it comprises a mix of largely propane and butane, with some lesser levels of other petroleum-based gases. Releasing the low pressure turns the liquid into a gas. The percentages of butane and propane vary from company to company, and vary from autogas to BBQ gas.

 

3. The price of a top of the range Falcon went from $5000 in the late 1960's to $20,000 in the late 1970's, for two specific reasons, not related to emission controls.

 

One - the late 1960's Falcon was "bare bones" - i.e. - it had no extras such as A/C, power steering, entertainment systems, electric windows, disc brakes, or even radial tyres. By the late 1970's, all the preceding "extras" were virtually standard fit, or available at extra cost, as demanded by customers.

 

Two, thanks to one economic genius PM known as Gough Whitlam, who spent Govt money on frivolities like a drunken sailor with a 6-month pay cheque, we endured inflation between 1974 and 1977 on a level never seen before or since in Australia. Inflation peaked at 17% in that period, and I can recall vehicle manufacturers printing new and increased price lists every month, in that era.

 

Emission controls added only a very small percentage to the cost of vehicles in that decade - because they were "tacked-on", not designed in.

 

What the tacked-on emissions controls of that era did do, was made engines sluggish, with revised late timing reducing power output, and increasing fuel consumption.

 

4. I don't believe the switch from Holdens to Falcons in the early 80's was due as much to size, as the fact that most Holden buyers were disgusted that GMH would supply us with a crappy, barely-disguised Opel product, that was built so badly, it cost GMH millions to strengthen the early Commodores, to enable them to withstand even mild Australian motoring conditions. The Commodores are still regarded with disdain by the true GMH believers.

 

5. CNG is not "virtually extinct". Around 35% of Perth's 1475-strong public bus fleet runs on CNG (512 CNG buses), with CNG proving to be a very suitable product for use in diesels, with very low emissions and increased engine life.

 

Of course, Transperth has a large dedicated CNG dispensing arrangement, which is lacking in the public arena. If someone poured the money into CNG service stations, there would soon be an increased uptake of CNG diesel-engined vehicles.

 

The only downside of the Perth CNG buses is their increased complexity, as they are converted from diesel to CNG, leading to a shortened overall lifespan, due to increased fire risk with extended age, as compared to straight diesel buses.

 

 

[Manwell]

Considering every possible engine design and fuel source, and since we mostly have ICE's already, the best fuel source would have to be water.  Most bang for buck  by far, and zero emissions.  Hydrogen/Oxygen.  

 

 

[onetrack]

Manwell, no-one has yet found the way to generate enough power on a large scale, from the disassociation of Oxygen and Hydrogen in water, by electrolysis - economically.

 

The electrical power required to disassociate the two gases is substantial, leading to only very modest energy output (taking into account, energy input) - and then trying to keep the two highly reactive gases separated without immediate recombination, is also a major problem associated with extracting "power from water".

 

However, it doesn't stop the HHO brigade on the internet from waxing as lyrical as fundamentalist preachers, over the "huge power" to be gained from electrolysing water.

 

They conveniently forget the electrical power input required is enormous, to get the necessary volumes of gases, needed to produce substantial amounts of power.

 

https://auto.howstuffworks.com/hho-system.htm

 

 

[turboplanner]

Turbo, I take issue with some of your statements;

 

1. "Peak Oil" is a furphy that is long dead and buried. Oil reserves are being expanded faster than we are using oil. Places such as Saudi Arabia have long been spoken of as their oil wells "running dry".

 

The truth is, Saudi Arabia has had to restrict oil production to keep oil prices inflated to levels where they can afford to buy more gold-plated Mercedes and Ferraris.

 

Who is telling the truth and who isn't, who is sitting on stock and so on would keep a person busy for months, but the world has started to pump more oil from deeper wells, and it is common now for drillers to put down curved bores to get to oil, but it doesn't really matter when you are about to design an engine for today, the price of fuel is horrifically high compared to what it was in the 1950s, and you can offset this cost by building an engine that uses less fuel. If you pick the fuel consumption of your old 1960s and 70s Holden or Falcon, and compare that to the 2 litre class today where Honda is achieving 4 litre/100 km on highway, and Mazda's 2019 SkyActive-X is targeting about 3.75 Litre/100 km, you can see there's a massive difference, so you can probably save yourself coming up with a 1930s radial engine design for tomorrow's recreational aircraft.

 

 

 

2. There is no such thing as "Lithium Propane". LPG stands for Liquified Petroleum Gas. The gas is actually a liquid under low pressure in LPG tanks, and it comprises a mix of largely propane and butane, with some lesser levels of other petroleum-based gases. Releasing the low pressure turns the liquid into a gas. The percentages of butane and propane vary from company to company, and vary from autogas to BBQ gas.

 

Well I used to specify, through Production Planning  "Lithium Propane" decals for Towmotor Fork Trucks. I'm not up with the chemicals but the combination for Propane is C3H3 and for Lithium Propane C3H7Li. I'm not sure what happened of the years, but Lithium is highly inflammable, so may have been dangerous, as highly polluting.  Liquid Petroleum Gas instead of Lithium Propane Gas doesn't make a lot of branding sense to me when, if Lithium has been taken out, you could call it PG. However I don't mind what it's branded as, the honeymoon for LPG is all over due to it's inability to meet current emission limits.

 

 

 

3. The price of a top of the range Falcon went from $5000 in the late 1960's to $20,000 in the late 1970's, for two specific reasons, not related to emission controls.

 

One - the late 1960's Falcon was "bare bones" - i.e. - it had no extras such as A/C, power steering, entertainment systems, electric windows, disc brakes, or even radial tyres. By the late 1970's, all the preceding "extras" were virtually standard fit, or available at extra cost, as demanded by customers.

 

Two, thanks to one economic genius PM known as Gough Whitlam, who spent Govt money on frivolities like a drunken sailor with a 6-month pay cheque, we endured inflation between 1974 and 1977 on a level never seen before or since in Australia. Inflation peaked at 17% in that period, and I can recall vehicle manufacturers printing new and increased price lists every month, in that era.

 

Emission controls added only a very small percentage to the cost of vehicles in that decade - because they were "tacked-on", not designed in.

 

What the tacked-on emissions controls of that era did do, was made engines sluggish, with revised late timing reducing power output, and increasing fuel consumption.

 

My $5000.00 was for an upmarket model with Rally Pack, so included those items, plus driving lights, extra instruments, paint etc. Those years of inflation would certainly not have helped. It would be interesting to cost up the emission percentage today which includes amortising the billions of dollars each company spends to achieve an ever higher bar. What's coming next are CO2 level Design Rules (As much as enivronmentalists have been talking about CO2 causing global warming, emission standards have been based on NoX and Particulates. Regardless of the amount, if we are designing an new engine today, and we want to use any automotive components, they will be more expensive. The aviation industry is also well overdue for cockpit noise levels, engine emissions etc. which will be politically driven

 

 

 

4. I don't believe the switch from Holdens to Falcons in the early 80's was due as much to size, as the fact that most Holden buyers were disgusted that GMH would supply us with a crappy, barely-disguised Opel product, that was built so badly, it cost GMH millions to strengthen the early Commodores, to enable them to withstand even mild Australian motoring conditions. The Commodores are still regarded with disdain by the true GMH believers.

 

I was working directly with the loser for much of that time, and we lost large market sectors. Virtually the instant the VN Commodore was released the tables turned and the new Holden Motor Company had a spectacular revival and Ford were on the rocks. I really feel for the guys who try to read those market demands in advance.

 

 

 

5. CNG is not "virtually extinct". Around 35% of Perth's 1475-strong public bus fleet runs on CNG (512 CNG buses), with CNG proving to be a very suitable product for use in diesels, with very low emissions and increased engine life.

 

Of course, Transperth has a large dedicated CNG dispensing arrangement, which is lacking in the public arena. If someone poured the money into CNG service stations, there would soon be an increased uptake of CNG diesel-engined vehicles.

 

The only downside of the Perth CNG buses is their increased complexity, as they are converted from diesel to CNG, leading to a shortened overall lifespan, due to increased fire risk with extended age, as compared to straight diesel buses.

 

The telling point on this side of the country was Benders Bus Lines in Geelong who had 100 CNG buses. They went back to diesel about ten years ago. Buses were the ideal product for CNG, long chassis to hold the tanks out of sight, accidents very rare, back-to-base refuelling etc, but I suspect the lead-foots wanting diesel performance probably added to the maintenance costs and increased fuel consumption and that was it for CNG there. My point is that if you are looking at powering a recreational aircraft, it's going to have a whole range of specific needs that you have to meet, and you can pretty much tell, if you look at the basic principles of the engine you are evaluating that you can fiddle and test until the cows come home, but if it has fundamental weaknesses for its application, you're better to rule it out.

 

 

 

[bexrbetter]

 The light weight for power would mayke such an engine attractive,even if fuel consumption is higher at high rpm.

 

 

 

(Mazda) Rotarys are not light, that's a fallacy that never sems to go away.

 

Nor are they, Mazda, powerful for their weight.

 

 

 

 

Many years ago I read of people experimental Rotary engines that tacked a third rotor onto the Mazda Rotary, apparently easily done.

 

 

 

Mazda made a production 3 rotor rotary, it's called the 20B.

 

 

[Manwell]

Manwell, no-one has yet found the way to generate enough power on a large scale, from the disassociation of Oxygen and Hydrogen in water, by electrolysis - economically.

 

The electrical power required to disassociate the two gases is substantial, leading to only very modest energy output (taking into account, energy input) - and then trying to keep the two highly reactive gases separated without immediate recombination, is also a major problem associated with extracting "power from water".

 

However, it doesn't stop the HHO brigade on the internet from waxing as lyrical as fundamentalist preachers, over the "huge power" to be gained from electrolysing water.

 

They conveniently forget the electrical power input required is enormous, to get the necessary volumes of gases, needed to produce substantial amounts of power.

 

https://auto.howstuffworks.com/hho-system.htm

 

Well, I'll be damned.  You mean people don't know how to do that economically yet?   I guess it would be a bit disruptive to the oil and Govt illusion.   It's not rocket science, ya know.  It's submarine science ...    

 

 

[onetrack]

Turbo, I have no idea where this "Lithium Propane" decal you speak of, fits in. I own an old Towmotor forklift, it is LPG from the factory, and nowhere can I find any "Lithium Propane" decal on it.

 

Maybe you're thinking of "Liquid Propane"? I think this may have been an American term in use in that era, for LP gas. 

 

I did find that there actually is an exotic chemical manufactured, called Lithium Propane - it costs $242 kg if you want any of it - and I can't see it being economic as an engine fuel, at that price!

 

https://www.elgas.com.au/blog/350-propane-lpg-whats-what

 

 

[bexrbetter]

5. CNG is not "virtually extinct". Around 35% of Perth's 1475-strong public bus fleet runs on CNG (512 CNG buses), with CNG proving to be a very suitable product for use in diesels, with very low emissions and increased

 

 

 

... every taxi, and we are talking 10s of millions of them, most buses, and most commercial mini vans as well as private taxis and many cars in China run on CNG.

 

There is about 1 CNG service station here to every 2 petrol stations in China.

 

It is about 1/3 the price of petrol (petrol is only a little cheaper than Australia here), and partly why I can go across town, lets say 10 to 15 minutes, in a taxi for about $2 to $3. .

 

 

[turboplanner]

Turbo, I have no idea where this "Lithium Propane" decal you speak of, fits in. I own an old Towmotor forklift, it is LPG from the factory, and nowhere can I find any "Lithium Propane" decal on it.

 

It was there in 1962. The model designation was something like 620 LP.

 

 

[Raytol]

I read a book detailing the early history of rotary engines. Felix Wankel tested several concepts before NSU took up the type we know today.

 

It said that one of the concept engines had "too much torque at low RPM to be useful to NSU (as the maker of sports cars) and as NSU had already done the gearbox design

 

the RPM of the engine output shaft was already determined"! That was the diameter of the star wheel was set early.

 

This meant to me that

 

1/. The 3 pointed rotor in a two shaped chamber was not the only concept tested. I think it said that the "Truck" rotary had a 4 pointed rotor in a 3 shaped

 

chamber. NSU said that it was too complex to machine ( in the days before CNC machines , additive manufacturing equipment).

 

2/. I don't know for sure but I would think that the "Truck" rotary would of had a much larger distance from the combustion chamber to the output shaft so that

 

the torque of the engine is increased.

 

3/. In the early days chatter of the seals was a major pain, been sorted with materials technology a long time ago.

 

4/. Silicon Nitride seals now last a long time even in highly turbocharged engines.

 

5/. The high energy exhaust gasses are ripe for turbocharging and compounding.

 

I don't think the concept of a rotary motor is dead but we may have to re-think the Mazda type set-up. I wish I still had this book but it was "borrowed" by someone.

 

 

[onetrack]

The bloke with the webpage linked below, has done an excellent history "write-up" on the Rotary engine.

 

It is just amazing how many companies invested huge amounts into their version of the rotary engine  - both petrol and diesel versions - and apart from Mazda, they have all been commercially unsuccessful.

 

One thing I never knew, was that Mazda cut a deal with GMH in 1974, to buy new HJ Holden Premiers - without engines - which were shipped to Japan, and fitted with a Mazda Rotary engine.

 

Unfortunately, the Mazda Rotary struggled with the HJ Holden Premier weight, and only 799 of the oddball HJ Holden Premiers were ever sold.

 

Then there's the Moller Skycar, which rates as the best way to pick as many losing design ideas as you can, to pack into one unsaleable product.

 

https://www.carthrottle.com/post/w3roj27/