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Imagine you’re an Irish engineer working for the British Royal Aircraft Establishment. Your name is Frederick William Meredith. You are Irish by birth but one day you discover Karl Marx’s Das Kapital and the Communist Manifesto and you really like it.
You like it so much that you decide to attend the Moscow Victory Day Parade and then betray your own country and become a Soviet agent and Spy which forwarded various classified military documents to the Russian Armed Forces.
A few years later your treason gets discovered. What do you think happens next? Well based on the crime it would be reasonable to assume that you lose your job at the Royal Aircraft Establishment and get sent to prison like all the other traitors.
But none of that happens. And that’s because you’re an engineer. And not just any engineer. You’re an exceptional engineer, so good at your job that not only do you not get arrested. You get to keep your job too. The authorities decide to take a calculated risk and continue to employ you because of your “outstanding technical” ability.
The Supermarine Spitfire and the Mustang P51d, probably two of the most iconic allied fighter airplanes of the WW2
Towards the end of the war, both were equipped with nearly the same variants of the legendary Rolls-Royce Merlin Engine.
So both aircraft made pretty much the same power at the same altitude. But the P51 Mustang was noticeably faster. How?
Yes, the P51 was developed after the spitfire so it had more modern aerodynamics, which certainly contributed to a higher top speed. But that’s only one part of the answer. The other is this intake right here which was designed entirely based on the work of Irish engineer Frederick William Meredith.
To understand why this intake is so important, we first must understand what limited further power increases of piston engine aircraft.
You see the Second World War was a horrible time for humanity but an incredible time for technology. But most piston engine tech, what it really does is that it finds ways to stuff more air and fuel inside a cylinder. The more air and fuel you manage to stuff inside a cylinder the more powerful your combustion. The more powerful your combustion the more heat it generates. So to prevent the engine from overheating you install a larger radiator to better cool the engine. But now you have a problem – big radiators cause big drag.
Drag actually increases with the square of air speed. So the faster you fly the worse the drag. This ultimately leads to a situation where an aircraft with a less powerful engine but smaller radiator achieves a higher top speed than an aircraft with a more powerful engine and larger radiators.
So in the end it was engine cooling that became the ceiling for aircraft piston engine power. But Frederick William Meredith didn’t like that and decided to solve it and he did because he didn’t see the heat generated by engines as waste….he saw it as an opportunity which ultimately lead to the P51 Mustang being designed from the onset with Meredith’s ideas in mind.
At low speeds there is no Meredith effect. We can’t create energy out of thin air, we need something to work with. We need the kinetic energy of the fast moving surrounding air to convert it into slow moving pressurized air so that we can transfer as much waste heat energy as possible onto the air so that we can expand that air to produce our thrust.
If we don’t have the kinetic energy to start with than we can’t really do our thing, this is why the rear flaps of the radiator scoop are open when the airplane is moving at slow speed. By opening the flaps we remove the restriction in the back which eliminates the thermal choke at the radiator, allowing the maximum volume of air to pass over the radiator and prevents engine overheating.
If you think about it the radiator belly scoop of the mustang is basically a mini combustionless jet engine because it functions on the same principle and contains within all the basic elements of the brayton cycle. That being said the net thrust produced by the radiator scoop was minimal and only possible in the right conditions, what to scoop did in reality is that it canceled out most of the drag produced by the radiators, which as we have seen contributed to a noticeably higher top speed.
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00:00 When You’re an Irish Communist But Your Engineering Slaps
01:50 The Same Engine But Different Top Speeds
03:01 The Top Speed Ceiling
06:05 War Thunder
07:29 What Goes In Must Come Out
09:59 Slow Down, Heat, Expand
13:39 Canceling out Drag Increasing Speed
16:54 Meredith Effect in Formula 1?
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Victory day parade before 1945? Yes, annual parades comemorating the October revolution were held and were called victory day parades before 1945. I should have explained this better but it would have ruined the pacing of the intro so I dropped it. You can see the info on Meredith's wikipedia page too.
Can you please make a more detailed video on SI engine knocking because, somewhere it’s written that knock is suppressed by rich mix and some say lean burns hotter so more prone to knock! I am just confused!!
Didn't the earlier French Arsenal VG-33 also have this design?
The oven analogy is flawed, the reason for the hot blast of air is actually a chimney effect as cold air is drawn in and hot air gets vented up at your face. The expansion of the air as the oven is heated is a real thing, but it vents as the oven heats due to the inability of the oven to hold pressure. If it was truly the effect as described, then every time an oven is opened the door would explode open with the extreme forces of the air pressure acting on the surface of the door.
'We cannot just make air out of thin air.'
~D4A
I believe you mistake the fact that Mustang and Spitfire share the common engine, it is true but they aren't exactly the same thing. The Mustang is powered by the Packard version while Spitfire is powered by the Rolls-Royce version
The RR Merlin and Packard Merlin share architecture, but they have a number of notable differences, one of them is a two piece block on the Packard version while RR doesn't feature that
So they use the same idea to create nuclear airplane???
Haa ? 0:15 attend Moscow victory parade and then spy from 1936 on ??
This is simply false and impossible.
This is spreading fake news !!
Video is awesome!
WarThunder russian scamware!
BF109 had better thrust to weight ratio and was better than mustang . They simply didn't have enough fuel .
So it's similar to ramjet mechanics. Cool.
It's not treason unless you're at war with the other guys
Excellent video but you've made a minor assembly mistake (relevant to the video's subject though). You've placed the Spitfire's radiator scoop incorrectly (obviously due to haste during the assembly process), so the intake is facing backwards and the exit (along with the flap) is now facing forwards! 🙂 Again, great video as always, congratulations!
Dude, you are getting weirder. Keep it up.
Meredith still managed to steal this secret because Soviet yak-3 also used the same system
thanks again!
ELI10. Love it. Thank you. Will subscribe in 2 sec. Once I press this send button.
Do not ever stop explain engineering and mathematicals like this.
I see your passion! Thank you for sharing, also, your own clips..in example with the shower hose. Brilliant!
Please do continue!
Oh I forgot to comment, will imbed in 'tis comment edit: We do Lego now in making models? With already coloured!? In my days we used superglue, we painted the model ourself.
People still fall for it?
for the run with bigger radiator, implying the more powerful engine, you obviously needed a bigger propeller
Well presented, well written, Youtube needs more content like this.
So an irishman whose country has been occupied by Britain is giving important information during the war against nazis to Soviet Union, yeah doesnt fit in the 2026 EU propaganda agenda.
Fair play to him, but point of correction, if he was Irish, he didn't betray his country, he just betrayed who he was working for.
Victory parade wasn't until 1945… so How did he became a soviet spy in 1936 after visiting victory parade in 1945?
Clever girl
well in a way did he really betray his country he was born just outside dublin you could argue he screwed the brits over out of loyalty to the republic lol well not really but i bet some where in a random pub in ireland during the 50's 60's 70's some one argued this lol
that and ww2 news of an irish citizen getting executed imprisoned or otherwise would be EXTREMELY hazardous for the north of ireland being fed by the south and then if the republic got closer ties with the soviets over this ya no british MI5 is dumb enough to hand the soviets easy points with a fledgeling republic of ireland
The Me 109, starting with the E version, was already utilizing the Meredith effect as early as 1939.
Надо было написать тягу, которую создавал этот радиатор.
тяги там почти нет. максиум компенсация сопритивления воздуха. больший эффек не от "реактивной тяги", а от более эффективном теплообмене в радиаторе. так что с инженерной точки зреня данное видео граничит с глупостью. и дальйшего развитя эта идея (реактивной тяги)не получила. наибольший профицит достигается за счет увеличения эффективности теплообменика при нимимальном сопротивлении воздуха. сам процесс замедления скорости воздуха – это главное достойиство. на современных самолотах используется именно этот эффект: маленький воздухозаборник+ система расширения каналов+ большой радиатор и выход воздуха с минимизацей турбулетности. например Lancair Evolution.
Teeeeechniclly, they didn’t originally have the same engines. It (the p-51) flies faster becasue of Britain and the Merlin engine ( god bless you rolls Royce) and the fact it struggled with altitude with the Allison in it. So yeah. History. For context. Because…facts. You’re welcome America…
An oven operates at ambient pressure it is not the pressure that is causing that hot air to escape from open the door I think that you understand this when you make this analogy but it is important to point out that one that's a convection oven so yes it does add a bunch of air but two that it is not the pressure that is causing the area to escape even if it makes a great visual to understand fluid dynamics
Keep it up Bro. Do you want to develop and Engine with me.
Ok,but now I want to see a Ford Mustang with the Rolls engine from a Mustang😂
so, he is not a Russian Spy, but Irish betrayer
I read about this in sport compact car 2 decades ago. Your explanation is great. The little bit of extra context made it make more sense. Mainly slowing down the air to gain as much energy as possible. In cars, you’re usually just trying to get mass flow rate as you can to cool, rather than gaining as much energy from the air to generate thrust.
2:19 omfg what a monster of a motor 💚
Мужик похоже из тюрьмы ведёт свои репортажи, судя по фону.
0:29 to be fair, Great Britain is not his own country, they’re his colonizers
War Thunder is made by Russian game developer. If you are European and do not want to go to real war, then stay away from the game.
Suck Push Bang Blow – A normal Internal Combustion Engine. Suck Push Burn Blow – a Jet Engine. In this case the P-51 instead of directly burning the fuel it heats the air and makes it expand with the radiators. Same principle. F1 does "sort of" use the Meirdeth Effect but as you mentioned it is not as pronounced at ground level; the operations of the cars don't make it very efficient and the heat differential is not as high. F1 Designers DO however take it into account. Great video. Let's see some similar ones like this. Loved it – aeroplanes AND engines.
the best example of "knowledge is power" 🤣
0:24 wait Moscow victory day parade before then of WW2?
Great video! I can use this for several different topics in my physics classes. Many thanks!
Great video!
man i love how you explain things there. keep it up o7 !
never better explanation yet… I still want a Merlin adapter to a supercar for the end of the world… but I can't afford it.