The Forgotten Giant: A Deep Dive into the Allison V-3420 Engine
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- Опубликовано: 24 июл 2023
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The Allison V-3420 was a WWII-era, U.S.-made engine that combined two V-1710s, creating a 24-cylinder, liquid-cooled W engine. Despite its powerful 2,600-3,000 horsepower, it faced competition from more successful engines like the Rolls-Royce Merlin. Intended for use in heavy bomber aircraft, its delay led to a missed opportunity as the B-29, its primary host, opted for the R-3350. The V-3420 was used only in experimental aircraft, notably the Fisher P-75 and XB-39 Superfortress. Today, it's a forgotten piece of engineering history, a testament to technological exploration amidst the pressures of war.
Please consider subscribing! While you may not consider the subscription feature useful -- like any rational RUclipsr -- it's how I measure my self-worth.
Have been subbed for several years. THX 👊 😎 🇺🇸
Again, your brilliant research and digging into engine history has really been educational for me. You should measure your self worth by my compliments 😀
Those engineers who developed all of the different types and configurations were like unto gods (small gods but still...) with the sheer wizardry of differing designs in such a short time span. Even part-time, sorta, where it comes to this monster
Very nice and well researched video. Thanks for sharing. It facinating to see how many different engine design configurations scientists and engineers were working on during such a short span of time before jet technology came along and remendered their endeavors obsolete.
Let's gooooooo! Another flight dojo video! :D
I've visited the USAF museum, the spec sheet of this engine doesn't do justice for just how huge it is for a piston engine
There are some awesome engines on static display at the Air & Space Museum at Dulles Airport!
Good video. It shows that real genius of the engineers, and the strength of American industrial might in this era.
christ, if there was one technology who's time was cut to short it was these engines.
EJ Potter had one of these things in a a tractor puller back in the seventies.
Rare back then, let alone today.
I'm not an engine guy, This isn't something that really catches my interest.
But as a military history dude I clicked on it and this was one of the most interesting, relaxing and fascinating videos I've experienced in awhile.
Thanks man! I try to give off that cathartic vibe, so I’m glad you picked up on it.
I consider myself an aircraft aficionado, but I just learned about an engine and some aircraft I have never heard of! Thank You!!!
@flightdojo, I subbed to your channel because of your videos on rare and experimental aircraft engines. I was hoping you’d do one on the V3420. You shared some facts I was unaware of. Sitting in my dad’s hangar is one of these rare V3420s. It’s a single output shaft variant.
Just right to power a kit-build RV7?
@@JohnSmith-yv6eq. Yes please!
The 127 litre (!) liquid cooled inline-radial Lycoming XR-7755 with nine radial ‘banks’ of four inline cylinders might be interesting. It arrived after the war _and_ after the jets with their seemingly infinite development potential.
These engines from decades ago are crazy. Imagine what engines would be around today if jet had never been invented.
Engines wouldn't really be any different had jets never been invented, because by the 1940s, pretty much every type of internal combustion engine had been at least thought of, written on paper, prototyped or put into production.
By the end of the war in 1945, fighter designs were already pushing the limits of propeller driven aircraft at around 500 MPH. I think the Supermarine Spiteful with a 2,420 HP Griffon engine had a top speed of 494 mph in level flight. What engineers and designers started running into was the limits of propeller physics and metallurgy. For those high boost pressures and extreme heat, they started to have to resort to exotic things like sodium cooled exhaust valves, water-methanol injection and all sorts of charge cooling. Had they had access to modern metallurgy, engines may have been able to be built stronger to withstand more boost without blowing themselves apart.
What kept all of those advanced engines out of more mundane things like automobiles is that they simply didn't need them. The average family sedan didn't need a 2,000 HP V12 with fuel injection. It was only in the 1970s-1990s when environmental standards started kicking in did engine manufacturers start re-inventing what already existed 30-40 years prior to try and get emissions down while getting performance up.
@@GGigabiteM Although many configurations had been prototyped, very few were put into meaningful production. There were a fairly large number of H-24s designed, but only one ever got to (relatively) large-scale production, the Napier Sabre (its predecessor, the Napier Dagger VIII H-24 had limited production, this little engine, a mere 16.8 litres, put out almost 1000hp in 1938). Indeed, the Sabre was the only 24-cylinder liquid-cooled engine to see production. It had significant problems, but not as many or as serious as all the other 24 cylinder engines, the Junkers Jumo 222 (24-cylinder water-cooled 6x4 row radial) destroyed the German Bomber B program, all by itself. The alternate German engines considered for Bomber B were even more diabolical.
Yes, materials have advanced considerably, especially coatings and treatments. The work done on poppet valves essentially made the sleeve valve used in the Sabre unnecessary. Mind you, the manufacturers spent far more on making the poppet valve work properly than Bristol did on the sleeve valve.
However, the real advances have been in precision manufacturing, even mundane modern production engines meet tolerances that would astonish the WWII engine builders.
AND, the understanding of combustion has advanced considerably. Although twin overhead cam 4 valve heads (penta-roof combustion chamber) have been around on paper since 1910 and in the flesh since 1911, they really did not work properly until the sixties, specifically Harry Westlake's V12s and the Gurney-Westlake V12, this was soon followed by the Cosworth V8s. Although WWII designers knew about tumble and swirl in the combustion chamber, they did not understand the critical importance of squish, and squish was the key to significantly improving detonation characteristics.
The Griffon was a far better-engineered design compared to the Merlin, yet the combustion chambers were far too big for it to be the powerhouse that many expected. The Max power out of 36.7 litres was 2420 but more typically 2375hp, the Merlins that powered the de Havilland Hornet were 2070hp each from 27 litres, a higher specific power per litre.
The production Spiteful was not quite as fast as what you quote and there is some controversy as to which was the faster, the Spiteful or the Hornet. Never mind, the point is clearly shown, the Hornet with 4140hp could not go much faster than the Spiteful with 2400hp. The Hawker Fury 1 prototype (LA610) powered by the 3055hp Napier Sabre VII, was a lighter version of theHawker Tempest VI interceptor. Also, like the Tempest I prototype (HM599), it had wing root radiators instead of the chin radiator. IMHO, it was one of the most beautiful piston-powered aircraft ever built. Its speed was similar to both the Spiteful and the Hornet. Its rate of climb was about the same as the Hornet (slightly slower,) but much better than the Spiteful and the Bristol Centaurus-powered Sea Fury.
All of these engines were quite wrong, their combustion chambers were far too large, they were undersquare (longer stroke than bore), their combustion chambers were the wrong shape, they had little to no squish and they didn't rev. The combustion chamber of Maj. Frank Halford's Dagger at 700cc was reasonably close to the optimum combustion chamber size (which has been determined by several manufacturers and research groups as about 500cc per cylinder), it was slightly oversquare and revved quite high - the aircrews in the Herefords hated it, it had a 30degree firing interval and ran at 4200rpm, which meant it sounded like a flat twelve running at 8400rpm, the thing screamed, the two engines could not be synched, they were very loud, and the air coolng was not suitable for such a high performance engine, consequentially it was unreliable.
l am Sub'ed and thanks for the excellent video...
Shoe🇺🇸
50k subs? YT is definitely keeping the cream from rising.
Fingers crossed!
Love the technical details
B-29's already look tough with the big chinned radial cowlings. Imagine the impression made by the four Carcharidon looking V-3420 nacelles that look nearly the girth of the fuselage. The almost 5,000hp variant you mentioned could have rivaled the early turboprop jobs and not burned or blead so much of its oil supply like the corcob radials did.
Another great history lesson
Love the videos. Keep up the good work
Dude!
its fascinating with all that goes into these (Military ) engines, they only lasted for about 250 hrs running time then replaced ...... the reason for this is weight had to make them as lightweight as possible great vid thank you.....
4:00 My business mentor was a combat PT Boat boss. He refused to sweat the small stuff.
Superb presentation.
Thankyou. I had previous known of only one of these engines.
I love this channel and your focus on the powerplants of the Second World War
Well done. The double 3420 is very interesting...
Great video! Always interesting to learn something about the past! It is amazing to see what people created with just slide rules, pencil and paper, and their imagination 👍
I'm sure back in the day, while choosing who would be involved in these incredible engineering projects. They first asked potential engineers what gender they identified with, what their race was, sexual orientation, then chose those with the lowest test scores, and placed them on their most essential teams.
I think the Michigan madman EJ Potter got ahold of one of these engines . And made a pulling tractor of it. For tractor pulling competition!
God what an engine 😮
Very interesting video, Thanks Flightdojo. 🇺🇸
I’ve seen one of these engines. It was at Tillamook Air Museum. This was about 15 years ago, I went a year ago and do not see it there anymore 😞
Not a V, but a double V, i.e. a W as found in some current VW products. Fantasy of Flight used to have some of these still in crates.
Man would love an overview the BMW 003 turbojet
Awesome engine, awesome video.
As this is Flight Dojo, no surprises then!
Thanks a lot!
It always impresses me that these engines were designed on paper using slide rules, without the 3-dimensional design aids, solid modeling, and computer aided analysis that we have today. Someone had to visualize in their heads all those interfering parts and all these close clearances, and stresses had to be calculated by hand.
It seems every X-24 layout was doomed from the start. In a way l am surprised Allison didn't take a look at their previous X-24. The X-4520. Off all the doubled engines proposed and built the V-3420 may actually have been the best. Primarily because it was less of a stretch than the others.
The engine at the 2:30 mark is obviously for the Fischer P-75 Eagle. An abortion birthed (1) from GM's desire not to get roped into building nacelles for B-29s.
1) two words that really do not go together.
Subscribed. The reason I don't subscribe or like is because RUclips will bombard you with similar videos. I'm interested in aviation, but not exclusively. I might watch a video on Llama shit, but you can guarantee I'll see multitudes of Llama video recommendations. Probably will now, just for mentioning it. Anyway, "if no one pays you a compliment, then give yourself one. " Twain.
Great video with excellent information! Does the XB-39 that used the W-3420 still exist?
+@CheeseheadMotors The XB-39 airframe was S/N 41-36954 and that is not listed with surviving examples. The B-39 was not ordered into production, and Fisher was instructed to shift focus to the P-75 Eagle, so it is likely that the XB-39 was scrapped at Wright Field.
I can't thnk of it as an engineering marvel, it is a paired V12 engine, I have never seen the benefit from doing this. The frontal surface areas looks to me to be greater than the total area of two separate Allisons. I always thought the idea of pairing two V12s into one engine and then using a complicated transmission system to power two propellers was particularly strange.
However, pairing two seperate V12 engines to a single propellor drive via an external gearbox would provide more flexibility and be much simpler, assuming the propellors could absorb that amount of powere. Alternatively, having a system where two engines drive indidual contrarotating propellors may also have further advantages at least in redundancy.
But really, twin engined fighters always seemed the best solution, both the Lockheed P38 Lightning and the post-war (it was designed and tested during the war) de Havilland Hornet are testiment to that.
never heard of this Lockheed XP58....you could make a video on it.
That looks much more straightforward to maintain than the Wright Cyclone. Both are clearly pushing the piston design limits.
The Napier Lion W-12 with three banks of four cylinders worked well with a single crankshaft, it powered the successful Schneider Trophy race Supermarine S4 to S5 series floatplanes. Could a W-18 version of the Merlin or Allison 1710 have worked, putting an extra bank of six cylinders in place? The big V-12 RR Griffon pistons were above the optimum size for a fast revving engine.
The Sunbeam W engines also worked well… but it is likely an X configuration to limit development costs and time. As a W opens up a large upfront cost in design and development.
@@captiannemo1587Did any X configuration engines enter production? The H-24 Napier Sabre was close to being dropped but most of its troubles came from sleeve valves. Perhaps with sodium cooled exhaust valves a conventional overhead or even advanced side valve engine could have been more straightforward?
Imagine a radial with diameter (and drag) reducing two sided cylinder side valves with 4 valves per cylinder. Aero engine low rpms, twin ignition and supercharging induction might tolerate the convoluted cylinder head? Side valves were known technology.
Why were there no three bank radials? Cooling seemed to be feasible with four bank engines.
@@givenfirstnamefamilyfirstn3935 X? Yes actually. Not very many at all but there are a few. The Viking seems the most likely to hit production.
1921 Airplane Engine Encyclopedia An Alphabetically Arranged Compilation of All Available Data on the World's Airplane Engines By Glenn Dale Angle
Can be found on google books.
Clerget - Type X - Experimental - French. 4 banks of 4.
De Don - 800 hp - Experimental - 4 banks of 4.
GOBRON-BRILLE - French 8 cylinder X type. 4 banks of two cylinders. Opposed pistons in each cylinder.
Hansa - 16 cylinder engine - Germany.
Napier - X type 16 cylinder - Cub - 4 banks of 4 - UK
The Sixteen-Cylinder Viking Engine (1919) - 4 banks of 4 - USA
Peugeot - Type 16 X - French. 4 banks of 4.
RR made a small number of Vultures.
@@eugeneoreilly9356 yah there is a lot more but those pre 1930 are not well recorded.
Regarding the Fisher XP-75: according to the excellent coffee-table book called "The World's Worst Aircraft"; the USAAF wanted General Motors to submit a tender for a new airplane and General Motors didn't.
General Motors was quite busy building FM-2 Wildcats and a numerous other weapons and vehicles, etc. and made the plane as complicated as possible in order to fail the USAAF trials. Decades later, General Motors would invent "planned obsolescence" so Americans would buy more new cars instead of fixing the ones they bought....
Did Allison ever propose a larger displacement V12, similar to RR Griffon? Also did Allison ever work on improving the super charger efficiency as a means upping its hp of their V12?
Aircraft forced induction implementation is almost exclusively for high-altitude performance and efficiency - not horsepower (at least not total rated HP, just a means of maintaining it as long as possible as altitude increases.)
Allison did develop both two-speed and two-stage supercharged versions of 1710, but they were late/post-war and I don’t think any actually flew or were used on a design.
Many believe the USAAC was far more interested in turbos over superchargers (or SC development/production) indeed the turbo-supercharged 1710s performed very well, but were complex and expensive.
The only area that saw some impressive supercharger development was with the Navy, but this was due to the fact that they essentially demanded radial engines AND refused turbos, both due to complexity, reliability, and maintenance. Some of the late-war Corsairs had incredible supercharger performance, such as the F4U-5s with TWO side-mounted, variable speed, two-stage superchargers(!!!) These superchargers were also automatically controlled, and the fighter was envisioned to have a combat ceiling of ~45,000’.
Anyways, the know-how was certainly there, but the radials saw most of the forced induction tech it seems, culminating in things like the power recovery turbines, etc.
As EstorilEm suggested, I understood that the V-1710 was always envisioned to be turbo'd, but the war probably happened just a tad too early for that to be practical, given the rarity of those devices in a wartime economy. Supercharging for high altitude was not really envisioned, hence the appearance of "what were they thinking?"
@@EstorilEm "Aircraft forced induction implementation is almost exclusively for high-altitude performance and efficiency - not horsepower (at least not total rated HP, just a means of maintaining it as long as possible as altitude increases.)"
I don't think that's true, and I suspect you are thinking of adding supercharging to light civil aircraft. The engines for these high performance military aircraft were designed from scratch with singe stage superchargers. This is one reason their compression ratios were so low. Aircraft intended for high altitude needed multiple stages of supercharging. Single stage forced induction was not just for normalization with altitude, and was definitely used to improve rated power sea level. Low revving diesel engines in heavy trucks and locomotives still use forced induction at sea lever for the same reason.
@@corystansbury The US Army 'stupid' policy for most of WWII insisted that high altitude aircraft engines must use a turbo-supercharger to avoid the parasitic power drag of a mechanical supercharges. A air cooled 2 stage 2 speed mechanical super charger was used in Navy fighter aircraft, so its not as if the US aircraft industry didn't have the knowledge or experience to do this.
Allison V-1710-143 was the aircraft engine used in the P-82 and used a external auxiliary supercharger powered by a PTO shaft. There was also the monstrous Turbo-Compound prototype using exhaust recovery turbines for additional power, with the bench test of the prototype was able to reach over 3000 HP using emergency power water injection. This never entered production, as developed late in WWII, This version was abandoned with jet and turbo-prop engines showing more power increase potential
@@EstorilEmR-2800-32W has two single stage superchargers. The first one used a fluid couple that essentially passed through an intercooler to feed the 2nd supercharger which was gear driven.
What did Wright do to improve the B-29 engine? Did revisions fix fielded engines? How many engines were made per plane? How many failures broght down bombers? Were there any creative field fixes later abandoned? What was the expected life of the engine at first and then later? Did the Russians copy both the early weak engines and later the fixes? or did they make their own improvements?
Go ahead and watch my video on the wright engine, I address a lot of these questions.
@@flightdojo Thank you.
The Russians had the sense not to put those unreliable 'power recovery turbines' on their copied engines.
👍👍👍
The Michigan Madman-EJ Potter built a modified pulling tractor "Double Ugly" with 1 of these engines
Bad ass, it’s time to start building newer versions of these engines out of cobble together LS V8 just so we can hear them
No mention of DB-606 and DB-610 which followed similar cocept?
They helped to shorten the war. The wëhräböös seem very quiet about _them._
A pic of the X-24 DB 604 is at time 1:38.
All designed without computers.
Ah, what might have been. B29 with that engine would have been quite something. B29 struggled to carry the weight of its defensive armament, probably would have kept it with the Allison engine powering it.
Fair play to General Motors Allison ,designing a conjoined or twin-pac aero engine that worked reliably, where Rollers and Daimler Benz failed miserably. Only fly in GM,s ointment is retaining the 1710,s weedy blower as without FADEC a turboed 3420 , fitted in the XB-19 would be a bear. Keep it simple like a Model 'A' Ford, a three speed two stage blower is a no brainer, far easier to fix , with such a blower, the 3420,s pony count at a rough guestimate at take power in low blower three thousand ,three thousand four hundred at 3,000 rpm, not bad on on army air force standard 100\130 grade petrol.
The way they ran the engine off the of two shafts instead of an idler gear between the two cranks with one shaft to the propeller seems unnecessarily complex and would move the engine further from airflow.
Twins v 1710 should be W 12 or W16 but they just added the numbers
perfect for WW3
Think of all that reciprocating loss!
good vid but why this annoying muzak?
so I get annoying comments and then have more engagement on the video
It's ubelievable what engineers could design and build with no computers, cad-cam or CNC machine capabilities, it was all sliderules, pencil and paper, manual machining and trial and error testing/modification.
Formidable engine but extremely complicated and expensive!. Put in proper perspective competing BMW 003, which was RM12,000, and cheaper than the Ju 213 piston engine, which was RM35,000. Moreover, the jets used lower-skill labour and needed only 375 hours to complete (including manufacture, assembly, and shipping), compared to 1,400 for the BMW 801. Easy to understand why everyone passed to jet engines and have far more development potential...
Can't imagine the Navy wanting a gasoline powered ship.
in those days nothing fast was diesel powered, the packard's in the normal pt boats were gas
Interesting how the allison v-3420 is viewed as an engineering marvel whole the Daimler benz DB610 is viewed as a pig. Both engines share a very similar concept
+@moell The DB610 allowed each engine to run independently. I think that provided a margin of safety. I'm not sure that the 3420 allowed this.
First 😆
First*
Slow down your narration- no one is chasing you. In English there are spaces between words.