Pulse Combustion

I suspect they are a bit noisy.

https://www.youtube.com/watch?v=EEHw9lInIfg

You could barely hear the Lennox Pulse furnace when running.

It had a thick cast iron combustion chamber.

It even had a PVC exhaust flue.

No wasted heat.

Lennox furnace is highly efficient,.....

by the way, I believe that was the V1 that had the pulse jet. The V2 was a rocket.

When your talking about efficiency\, you have to define it. If your talking about the Lennox, yes, it is efficienct,.... if you talking about the V1,..... it did the job as a jet. These two had two very different goals.

Obviously,the end objective of the bomber was different,but the basis for the engine

was the same:

Get the maximum combustion efficiency possible,which translated into range.

In the V1,it was distance covered for a given fuel supply.

In the Lennox,it was the same;maximum combustion efficiency of the fuel,which

translates into heat,for the Lennox.

It is interesting that we have not made any great strides since then.

Even the Stealth Bomber is a copy cat of a Flying Wing developed by two brothers in Germany .

They used charcoal coating to absorb radar,and reduce radar signature.

If they had been allowed to put jets into them,we would have lost the war.

The Germans were great engineers.

Too bad they were corrupted by a madman.

IMHO, they are still some of the best engineers.

Actually, such German designs might have prolonged the war in Europe, which would have meant that several things would have eventually happened:-

1) Germany would have had an atomic bomb dropped on it in either late 45 or early 46. The Germans were developing their own bomb as well, though they were far away (years behind) from the state of the Allies version. My personal guess though would have been German capitulation after Japan was A-Bombed, if the war had continued longer in Europe.

2) Due to the Allies night and day bombing, particularly from 1943 onwards, Germany was mostly in ruins. It slowed them down considerably. Also, many cleverer than I say that 1943 was the main turning point as the Allies pushed Germany and Italy out of North Africa.

As Winston said at the time:-

"Now this is not the end. It is not even the beginning of the end. But it is, perhaps, the end of the beginning."

Really from this point on, the war was lost for Germany, well before V1s and V2s, jet aircraft and flying wings. Too little, too late. The day and night bombing stopped the German progress in such machines.

By the way, the flying wing was copied by the US Air Force in many areas, even for the B2.....they are similar, although radically different in size, in many ways....

3) The British army built many aerodromes in Turkey, still neutral at the time from late 1940 onwards, my Father was there doing just that at the time. Sent there by Winston. The German and British Consulates were next door to each other in the same building!! The plan was to start bombing Germany from both directions if the war went on after 1945 (nobody knew if the A-Bomb would work, that is of the few who even knew about it at all!!)

4) The war ended and Turkey was still neutral. The Turkish prime minister asked Churchill what his country would be getting out of Germany, Winston told him that he would not get anything, as he had been taking the hundreds of planes and tanks sent to him at a high cost to the UK, plus a small British army building harbours, aerodromes and the like, but due to Turkey staying too long neutral, could not actually be used in wartime.....

5) the UK "Home Chain" radar system to detect "incoming", reduced severely the damage (still extensive) in the UK, whereas Hitler thought a similar system for Germany was not needed.

6) In 1943, the RN developed several "Forward Firing" Anti Submarine Systems, that allowed an attacking Navy ship to "Kill" a sub without having to sail over it, thereby "losing sight" of it for valuable seconds....I actually worked intensively on one of them that was still in use through into the early 60's, it was that good!! Though most early kills were with Hedgehog I believe mostly....

(On an exercise with a US Sub in the 60s, using 400 Lb. "dummy Heavies", the target sub said we were not even close to hitting them (Hydrophone listening).... They surfaced, and wanted to use the "Fin" to get out as heavy weather did not allow them to use any deck hatches, they found that they could not open the hatch as one of our bombs was lying across it!! We had to send a sea boat full of men to move it to one side!!! DUUHHH!)

In conjunction with "Enigma" information from Bletchley Park, this seriously reduced both the capability of German subs to find allied shipping, and the Allies were far better at wiping them out, when they did attack a convoy.

This is naturally not the whole story, but basically, as I just wrote, from 1943 onwards, Germany was bound to lose, it was just a matter of when, not if!

Luckily for us, Hitler was an amateur and made one bad decision after the other, thereby "helping" the Allies further.....if he had had his own generals in charge, we might all be speaking German as a first language today.....

A further subject, that even many, quite young, Germans still cannot "handle" is that they, the Germans/Nazis were SO bad, the Allies were SO good, so they spend considerable time and effort in trying to prove that the Allies only won because we carried out even "nastier" acts than the Nazis did....

Things like Bombing Dresden in early 1945 for example......but as Dresden was the Radio command city for the eastern front, it was a fully legitimate target.

Also the Nazis were STILL sending POWs and Jews on long marches to nowhere in particular, just to kill them.

Also, Jews were still being killed in various Concentration Camps, as were other nationalities. Bombing Dresden did not even stop those atrocities.

Germany had in 1944 decimated Warsaw, Poland, plus were retreating from Russia used a scorched earth policy.....and and and......

All well documented on the web.....

I hope that this puts the facts a little straighter for any interested.

GA for the history lesson. Good summary, though you might have given a bit more credit to the USSR in the defeat of Nazi Germany. Not that I'm an apologist for Joe Stalin and the commies.

USA still doesn't have clean hands in the German War Effort. USA had over 300 companies trading with Nazi Germany before and during the war. Transactions were masked by Wall Street. We seized some of the assets of these companies in order to get them working for the US War effort. After the war all assets were returned and no one was charged with treason. One famous name that keeps coming up is Prescott Bush, but he was only one of many and a minor one at that but his son and grandson became President of the USA so he's become the most infamous one.

Shell Oil being one of them.

As well as Standard Oil

Standard Oil of New Jersey to be exact. They even told Roosevelt that if he did anything about them, Standard Oil would cut off supply to the US.

Dupont, Singer, Ford, GM, Remington, Union Bank, Beyer, anything and everything dealing with Aluminum.

Ford and Hitler had a picture of each other in their respected offices.

Now that one I doubt is true (they kept them in their wallets).

I love it when threads go so gloriously off topic :-) some really interesting history here.

My question is have things changed any? With all the 'sanctions' in the world today I imagine corporations are being just as devious in the name of profits.

Drew K

You doubt it huh?....

well when you're sure,.... come talk to me....

ps

hint: start reading first paragraph after 'Henry Ford: Hitler's First Foreign Backer'

and to add to your post.....

No, capitalism has not changed....

Also to add more details on my post about shell oil....... Shell Oil Based in Texas whose parent company was Royal Dutch Shell, a multinational company based in the Netherlands.

Whoa! Copyright 1998, last updated in 2001 with a Netscape 3.0 tag no less. I'm sure this is all peer reviewed right?

Captain: DELETE*****

Scotty: Too late Capt'n

Captain: ERASE******

Scotty: I'm givinr all shes got capt'n

Captain: RETRACT********

Scotty: Ship already sailed on that also

Captain: DIVE, DIVE, DIVE and scuttle her.

Ford, GM and Singer all three had working American Managed Factories in Germany during WWII, all three used slave labor from the Concentration camps and answered to US Company headquarters.

Two of our earliest CIA Directors, John Foster Dulles and Allen Dulles, Brothers, one worked in Washington DC in charge of directing US bombing missions, deliberately gave bad bombing coordinates to miss those factories, that would be Allen Dulles. John Foster Dulles, headed up Wall Street in the masking of US trades with Germany. They named an International Airport after these traitorous brothers.

The #2 source for Nazi propaganda in Germany was written by Henry Ford in some Anti-Semitic paper that he produced.

The #1 source was written by Martin Luther 400 years earlier.

https://en.wikipedia.org/wiki/The_Man_in_the_High_Castle

I think that you may be confusing the pulse jet engine of the V1 with the A4 rocket engine of the V2 which was a true liquid fueled rocket engine that was fueled with Ethanol/water and pure Oxygen. The fuel and oxidizer pumps were driven by steam created by the mixing of H2O2 and NaMnO4, and - as far as I am aware - there was no pulse firing involved.

You are right.I should have said V1, aka: "Buzz Bomb" instead of V2.

My bad.

It used a simple flapper valve opened and closed by external air pressure.I don't believe that type of pulse jet engine uses valves. It basically pulses off of pressure differential.The valve type (V1) used flappers, the drawback of the flappers was longevity.

A more simple one is a Ramjet. Simply but inefficient by a number of standards.

In my younger days, I built one that ran off of propane..... I spent more time working on the fixture which looked more like a (merry-go-round) that on the jet itself. As far as the time building the ramjet, what took the most time was machining the injectors.

Fortunately when I was 15 years old, I purchased an old Leblond lather (18" swing 108" bed) and rigged a sears Craftsman dremel-type tool (similar to this) on the cross feed for doing the angled drilling.

You do remember what the Allies called those things?

BUZZBOMBS.

Could be a problem in a continual use close proximity working environment.

Perhaps not that efficient as the Germans went to a rocket (the V2) as the buzz bomb's replacement.

Probably not so much about effiency as stealth. They heard the V1 coming across the Channel way before they got there. A V2 was nearly silent. Radar was rather primitive then. Sight was still very important. Given a choice of a surprise bombing versus one announced by sputtering engines, well....obvious choice.

And speed. The V1 could be intercepted. The V2, not.

It also depends on what you define efficient as.

Number killed/buildings destroyed versus cost of building might be the definition during war.

I'm thinking it was more like the SCUD, a lot more psychological than physical damage. From what I understand, they were not very accurate (but that is not a requirement for a psychological weapon). Actually more people were killed producing V2s than were killed by them.

https://en.wikipedia.org/wiki/V-2_rocket

True, though only a few aircraft were fast enough and if you caused it to drop, it still might kill people on the ground, and if you blew it up, you might get blown up with it......

Then there was the fear it engendered as it passed over on its way to London.....not to be forgotten!

The British Government organised a plotting system, that reported the bombs all landing farther north than actual. This caused the Germans to alter their aim southwards, till they were hitting farming country south of London, but being then "reported" as hitting London on the radio news!!!

Clever!!!

There is some good infos here:-

V-1_flying_bomb

The policy of diverting V-1 impacts away from central London was initially controversial. The War Cabinet refused to authorise a measure that would increase casualties in any area, even if it reduced casualties elsewhere by greater amounts. It was thought that Churchill would reverse this decision later (he was then away at a conference); but the delay in starting the reports to Germans might be fatal to the deception. So Sir Findlater Stewart of Home Defence Executive took responsibility for starting the deception programme immediately, and his action was approved by Churchill when he returned.

I've also heard that the British frequently referred to the V1s as Buzz Buggers.

Getting back on topic, the process doesn't scale well at all. The Lennox unit was designed for low temperature rise air heating operation, and used a tube and fin heat exchanger in the cold air path to condense the products of combustion by recovering the heat of vaporization to preheat the room air before it reached the outside of the combustion chamber.

The large gain in efficiency over a normally aspirated unit came from the elimination of the need for a draft hood and tall chimney to draw out the combustion products. There are no free lunches and the price was paid in control complexity and rapid corrosion of the low temperature metal surfaces now wetted by the acidic combustion products.

The two technologies have also been combined in hydronic systems where the return water is preheated by the pulse combustion product exhaust stream which is condensed in exactly the same manner as the hot air system. The main difference is the operating temperature, thickness of the metal in the primary heat exchanger, and its overall resistance to corrosion.

Think the Nazis were more interested in a simple inexpensive lightweight propulsion system for the vengence 1 (V-1) flying bomb than efficiency. It was a one-time use system and only had to last for a few hours. Other powerplant options were too expensive or too heavy for the mission. Why do you think the pulse jet is so efficient? It is fairly simple and cheap to build but it is noisy, vibrates as you would expect pulse combustion to do, doesn't throttle down well, and the shutters limit reliable life.

Wrong missile....

The V1 used such an inefficient pulse jet system, not the V2.......you will notice that the engine exhaust flame is yellow, demonstrating that unburnt fuel is leaving the engine before burning outside......modern versions burn far cleaner it would appear.

After WW2, many amateurs used similar pulse jets for model aircraft, nowadays they tend to use proper tiny jet engines for such models.

Pulse jets are still flown by the modelers it would seem and due to the better design of the engine and the far higher pulse frequency, efficiency seems to have been improved substantially over earlier versions, optically at least:-

Modern Model Pulse Jet Engines Flying (dangerously!)

WWWII V1 Flying Video

Modern Built V1 Engine Running

V2 Rocket

In answer to your questions, I feel that such a boiler may be possibly too loud for domestic usage. For industry I am sure someone here will know best.....they have been around for many years it would appear.....

The question is, why haven't they caught on if they are so efficient and do not require a chimney....It seems only price is against them!!

Pulsed Heating Systems

Good question in spite of the errors......