17 replies to this topic

[mariner]

As the auto industry moves form pure IC through hybids and struggles to get publically accepted range out of EV's I am reminded of passenger planes in the early 1950's.

 

During WW" the Brits and Germans focussed on jet engines as air superiority was much more important than long range. The US led on large air cooled radials , fuel effeicent so the B29's etc. could carry a decent bomb load to Japan , and to power their huge production of transports like the DC4 .

 

The first generstion of passenger planes  were all US and used the well developod bomber engines to give transatlantic range at last . Like the Boeing Stratocruiser,the Lockhed Constallatiion and the DC6.. The engines were very comples with 28 cylinders ans 56 valves and plugs. Taht complexity caused heavy maintaince , acceptable in war but not for cheap air flighs 

 

Then the military realised that their piston bombers were to vunerable against jet figthere as in Korea so demanded more fuel efficent jet engines for range.Those engines led to the  B47 and B52 in US and the V bombers in UK . 

 

As ever miltary budgets paid for a technical advance with  better materials for example  the constantly hot combustion chambers being key.

 

Just like hybrids there was an attempt to marry jets with propellers for more effiicecy and th Brits built three turboprop passenger planes , the Viscount, Vanguard and Britannia while Lockheed did the Electra ( not wholly succesful but its engines and wings basically live on in the ubiquituos C130. The benefit of the turboprop was better efficincy at lower speeds and altitudes 

 

Finally the aero engine guys learnt to make huge fans ( the CF ones bankrupting Rolls Royce ) which gave the slower stream efficency advantage of the turboprop but no big, heavy expensive prop gearboxes.

 

Sounds somewaht similar to wher we are on IC vs Hybrid vs EV today??

 

 

[Bob Riebe]

Not really, all the aero items used liquid fuel which could be replaced in , depending on tank size, rather quickly.

You push hard , because you have to, and run your battery dry, especially in the frigid North, you are screwed in a bad way.

 

Internal combustion and turbines can be made to work just long enough to get where one must go by locating/purchase (have used white gas and mixed gasoline, in an emergency) fuel that may not do the engine any good but enough to make it run.(rubbing alcohol is better than nothing or as Parnelli Jones found out Tequila will work.)

You cannot replace fuel in an elecromobile quickly in an emergency.

Edited by Bob Riebe, 07 April 2025 - 21:01.

[GreenMachine]

What is your point Mariner?  If you are trying to say that a new technology evolves, perhaps in several directions, I think we already know this.  If you are tying to say that a new technology may be hailed as a panacea or over-hyped, and reassessments of its strengths and limitations occur over time, well quell surprise.

 

Your question might be better phrased 'how do we see the EV/ICE/hybrid powertrains evolving' into the future.

 

Bob, that is a straw man and you know it.  Not saying that some people aren't trying to run EVs in ultra-unfavourable situations (you always get somebody like that), but as I have indicated when you have brought that up previously, if it isn't suitable you get something that is (more) suitable. 

 

As to refuelling, I do believe that I have seen something about the AA/RAC/similar working on solid state batteries (capacitors?) for a short range boost for stranded EVs.  That though is not targetted at your Tesla stuck in the middle of the Sahara, or somewhere north of the Artic circle.  The recent Chinese leap in reducing charging time is, I suspect, indicative of a major focus of battery makers and the vehicle manufacturers on range and recharging improvements.

[Wuzak]

During WW" the Brits and Germans focussed on jet engines as air superiority was much more important than long range. The US led on large air cooled radials , fuel effeicent so the B29's etc. could carry a decent bomb load to Japan , and to power their huge production of transports like the DC4 .

The British developed liquid and air-cooled piston engines for most of their fighters.

Jet engines were developed as well, but didn't get into service in WW2, except for the Gloster Meteor.

The Americans were also developing jet engines, many based on British designs. The Lockheed P-80 prototype flew on a de Havilland jet engine, while the XP-59 had two earlier Whittle designs.

There were several proposals for jet bombers towards the end of the war, but, as far as I know, none were built.

The Germans, on the other hand, were desperate. They were being outproduced, so needed a technological edge to be able to compete. Thus the various jet fighters and bombers, along with high perforamce piston aircraft as well.

 

The first generstion of passenger planes  were all US and used the well developod bomber engines to give transatlantic range at last . Like the Boeing Stratocruiser,the Lockhed Constallatiion and the DC6.. The engines were very comples with 28 cylinders ans 56 valves and plugs. Taht complexity caused heavy maintaince , acceptable in war but not for cheap air flighs

The first generation of passenger planes were largely WW1 types, developed through the 1920s.

 

Improvements were made during the 1930s with models like the Douglas DC-1 and DC-2 and Boeing Model 247.

 

The Boeing Stratocruiser was, essentially, a B-50 with a new fuselage for passengers. It was developed from a military transport version of the B-29.

 

The Douglas DC-6 was developed as a military transport, and then made into an airliner after the war.

 

The Lockheed Constellation was originally intended as an airliner. It started life as a military transport aircraft.

 

Post WW2 there were quite a few surplus military transports which would be used as the backbone of the airline industry.

 

The DC-6 used Pratt & Whitney R-2800 18 cylinder radials and the Constellation family 4 Wright R-3350 18 cylinder radial engines.

 

The Stratocruiser used the R-4360 28 cylinder radial, which was not a popular choice with airlines, for the reasons you said.

 

The follow-on from the DC-6, the DC-7 used R-3350s too. Later versions of it and the Constellation used the R-3350 turbo-compound engines.

 

Over in the UK there were airliners based on the Lancaster named the Lancaster, for example, with the Bristol Brabazon (8 x 18 cylinder Centaurus engines) as a new design.

 

And there was the de Havilland Comet, which fir flew in 1949.

 

Then the military realised that their piston bombers were to vunerable against jet figthere as in Korea so demanded more fuel efficent jet engines for range.Those engines led to the  B47 and B52 in US and the V bombers in UK .

Certainly the USAAF/USAF were aware of the potential issues that jet fighters posed for the B-29/B-50.and had organised trials against jets like the Meteor well before the Korean war.

 

The B-47 first flew in 1947. The first proposal that led to the B-47 were from 1943.

 

There was also the NAA B-45 bomber, which was in service before the Korean War, though it was not a long range heavy bomber like the B-47. There were also the Convair B-46 and Douglas B-48 prototypes.

 

Many of the aircraft used in the Korean War were left-overs from WW2.

[gruntguru]

It is worth mentioning that jets of that era were LESS efficient than piston engines - particularly the Wright Turbo Compound. The jet advantage was power, weight, speed and performance at altitude.

Edited by gruntguru, 08 April 2025 - 03:19.

[GreenMachine]

The Brits and the Germans had jet engined fighters prior to the end of WW2, and if you include the Me262 Germany had two 'bombers', the second being a proper twin jet light bomber (an Arado) seen in action at the close of the war in limited numbers.

 

The Brits lagged with immediate-post-WW2 commercial passenger planes, as far as I can tell due to their reliance on military mostly liquid cooled engines, engines produced with the expectation of short lives - there was no thought of a veneer of civility or possible potential reuse in an altogether different environment - long haul, long TBO.  This may have been a case of optimism about jets but waiting too long, certainly (obviously) DH put all their money on the Comet and for a long time they were the only game in town.

 

 

It is worth mentioning that jets of that era were LESS efficient than piston engines - particularly the Wright Turbo Compound. The jet advantage was power, weight, speed and performance at altitude.

 

Exactly - efficiency be buggered, we want effectiveness.

 

I suspect that the breakthrough was the low bypass turbofan, turboprops being a branch line going nowhere much but serving a noble role as standin until the jets got their act together.  And we know what happened then, the turbofan just took off, metaphorically and literally.

 

Grunt, do you know how a modern state-of-the-art turbofan stacks up for efficiency against the Turbo Compounds?  Presumably the measure is sfc/power?

 

 

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[GreenMachine]

Certainly the USAAF/USAF were aware of the potential issues that jet fighters posed for the B-29/B-50.and had organised trials against jets like the Meteor well before the Korean war.

Yes. AFAIK it was more a case of the ongoing issue of defending big, slow(er) bombers from the faster, more maneuverable fighters, an ongoing problem inherent in the nature of the opposing combatants which continues today.  Tactically, the issue would have been more about what equivalents have we got to throw at 'their' attackers.  The new jet engines were developing rapidly, and there were new design/aerodynamic challenges leading to more uncertainties than existed in the relatively slow developing world of the piston engined combat aircraft.

 

The only bomber I can think of to crack the problem was the Mosquito bomber variants, which could take a B17 bombload to Berlin with relative immunity - until the Me262 arrived.  Maybe the B47, I'm not very familiar with that one? 

[Wuzak]

The only bomber I can think of to crack the problem was the Mosquito bomber variants, which could take a B17 bombload to Berlin with relative immunity - until the Me262 arrived.  Maybe the B47, I'm not very familiar with that one? 

 

The B-17 bombload to Berlin is a bit of a myth.

 

The B-17 could carry 5-6,000lb bombs to Berlin, the Mosquito only a single 4,000lb bomb. The maximum load the Mosquito bomber could carry was 5,000lb (1 x 4,000lb and 2 x 500lb under the wings), but only for shorter ranges.

 

The B-17 would also carry incendiaries, which reduced the total bomb load.

[Bob Riebe]

It is worth mentioning that jets of that era were LESS efficient than piston engines - particularly the Wright Turbo Compound. The jet advantage was power, weight, speed and performance at altitude.

Bravo.

It was speed that the jet provided, and due to the German recon jets, flying without any way of stopping, during WW II, the U.S. sent  two Lockheed YP-80A Shooting Star aircraft, part of a small unit sent to Europe for service tests, flew in Italy during World War II, seeing limited service on  missions in February and March 1945.

[mariner]

I think I was trying to make two points.

 

Firstly engineering is an evolution but gets accelerated by government funded urgency, wars, the  Apollo mission etc, because commercial investment trade- offs don't count.

 

Secondly, the turbo prop was similar to the hybrid as stop gap to try to cover the problem shared by early jets and current EV batteries - lack of range. 

 

Turbo props still have role in aircraft, witness a range of private planes and the C130 as well as the Airbus 400 C130 rival which although first flown in 2009 still is a turbo prop.

[gruntguru]

Commercial turboprop aircraft are still very common. They are a better solution than jet aircraft for short hops and low passenger counts (the crossover point seems to be about 100 seats).

 

Regarding efficiency. Modern gas turbines are around 40% TE and in aircraft use, exhaust thrust add a bit to the basic shaft efficiency. Wikipedia lists the Wright TC at 35.5% TE and the Europrop TP400 at 39.6%. https://en.wikipedia...uel_consumption

[GreenMachine]

I think I was trying to make two points.
 
Firstly engineering is an evolution but gets accelerated by government funded urgency, wars, the  Apollo mission etc, because commercial investment trade- offs don't count.

 
I don't know what you mean here.  The first part (up to 'etc') is pretty self evident and well known.  However in an emergency, don't underestimate the broader contribution that is not government funded, and again DH and the Mosquito are a good example - while eventually it was picked up for government funded production, IIRC the prototype was privately funded.  I have a feeling that some of the Miles aircraft were also privately funded in whole or part, and I think some of the early work on what became the P51 was privately funded, or maybe it was funded by the Brits (installation of the Merlin?).

 

However it does not take a war or NASA spending billions for technology to undergo development - it is inherent in the human condition to seek to build a better moustrap, and any and all products, inventions (that are realised), and technologies will be developed., 
 

Secondly, the turbo prop was similar to the hybrid as stop gap to try to cover the problem shared by early jets and current EV batteries - lack of range.

 
Who says that range anxiety was THE reason for the development of the turboprop?  It might have been ONE of the reasons behind the development of the turboprop, but I can think of several others, including simply that it was an attempt to marry the known (the propellor) with the new (the turbine as energy source), and every high HP ICE aeroengine of the time had a gearbox anyway.

 

I think that superficially there are overall similarities between the two where the 'hybrid' comparison can be recognised, but I am loath to take it further than that.
 

Turbo props still have role in aircraft, witness a range of private planes and the C130 as well as the Airbus 400 C130 rival which although first flown in 2009 still is a turbo prop.

Yes. Though I would quibble at 'a range of private planes', anyone able to afford a turboprop plane would be on the ladder to a small jet, unless rough field/STOL was in their requirements.  At the low end, big single turboprops (Caravan, Pilatus) are generally (principally?) operated by corporations or well funded institutions (eg RFDS). Yes, as mentioned also by Grunt, short/lean commuter trips are bread and butter for them, the other category is as turboshafts in helicopters, I doubt there are many ICE powered helicopters in the West of more than four seats.

 

Grunt, I am surprised that a big turbofan and the LP400 are line ball.  I wonder about the thrust from the 'hot' section, as the work done there to turn that big fan must surely generate appreciable thrust..  The determinate would be how efficient the turbine driving the fan is at capturing that energy, and how much is left over.

 

ETA:  Further reading says DH were contracted to construct the prototype Mosquito.  It would appear that the prior investment to get to that point may have been wholly or partly funded by DH.

Edited by GreenMachine, 11 April 2025 - 05:13.

[Magoo]

I'm paraphrasing from memory, but LJK Setright once wrote something to the effect of if God intended man to fly, He would have given him wings. But instead, She gave him the intellect to invent the gas turbine. 

 

Fom some angles, the development of piston engines, supercharging, turbocharging and turbo-compounding et al eventually led to a logical conclusion: throw away the pistons and associated junk and keep the turbine. 

[mariner]

Magoo's logic matches that of Keith Duckworth when he was attacking the F1 turbo regulations . Of course he had a large commercial interest in stopping them but his point was that if you make the turbo big enough the pistons are just sort of transmission turning the turbo gas thrust  ( unlimited by rules) into traction .

 

So similar in way to a turboprop !

[GreenMachine]

The process starts with a gas generator.

 

Choice - ICE or turbine to generate the gas, pipe gas through another turbine to generate power.

 

Use power to drive a 'propellor' of some sort: Big fan in HBPR turbofans, a propellor in turboprops, rotors in a turboshaft helicopter, compressor wheel in a turbocharger or pumps/generators in other applications.  I think RR RB211s have been used in electricity generation.

[gruntguru]

A range of aircraft jet engines have been used in electricity generation duty.

 

RR Avon very common - lots of them still in operation. https://en.wikipedia...olls-Royce_Avon The Avon was RR's first axial compressor jet (1950). To generate electricity an independent turbine was added to the exhaust - the Avon serving as a gas generator.

[Greg Locock]

Many decades ago I sat through thermo (it is obligatory that ME students resent thermo- in reality I didn't-engines are fun) and one lecture that stuck with me was given how Carnot efficiency works you really want a high temperature in combustion, and given how real world mechanical efficiency works you want a concentrated ie high pressure energy source. We then worked through what the ideal operating fluid was, but that was not very realistic.

 

Turbines are ludicrously long when asked to expand high pressure gas, so you end up with a piston expander to do the big expansions, and a turbine to do the low pressure expansion.

[Magoo]

I'm paraphrasing from memory, but LJK Setright once wrote something to the effect of if God intended man to fly, He would have given him wings. But instead, She gave him the intellect to invent the gas turbine. 

 

 

What an odd, brilliant, and interesting duck he was.