The Ki-64 “Rob”; Doubled Up Engines, Evaporative Cooling…What Could Go Wrong?

[@Teh0X]

Synchronizing Browning type machineguns to shoot through contrarotating propellers? Hardly worth the try.

[@offshoretomorrow3346]

It would shoot through them ok ( ;

[@xkgbciax5286]

@@offshoretomorrow3346 you could have 4 4 blade props in row in front and it would not ever even be close to shooting the props theres just so much space between them shots moving over 3000 fps most props Up to about 2,800 rpm. so ever see a pic of prop where the snap freeze it look at all the space that props are not there so even a slower gun will always get thru if the cam is match to the guns fyi this was done in ww1 and the zero and many other planes in ww2 shot thru the props ( why they dont do it in most ww2 plane was the smoke and flash a auto gun will makes but the pilots did like the guns in front like in p38

[@kevinoliver3083]

​The Japanaese used Browning system guns in 12.7mm, 13.2mm, 20mm, and 30mm. Not just in rifle calibres.

[@anzaca1]

The early P-40 variants had synchronised .303 Brownings.

[@Achates72]

That must of been some fantastic flying. Imagine an engine right behind you catching fire and you still manage to get the bird back on the ground.

[@13stalag13]

You do a great job Ed, keep it up please.

[@leeverkist2178]

I agree!

[@elennapointer701]

Yet another one I've never heard of. Keep this up!

[@tomlobos2871]

intresting how long these ideas were held. both evaporative cooling and twin engines in a mono fuselage. would have been easier to make it a push/pull configuration or just a pusher with carnard wings. oh wait, didn't they....

[@kyle857]

Push pulls come with a lot of their own problems.

[@WarblesOnALot]

@@kyle857 G'day, Yep, they sure do. According to Eric Brown they're Buggars for setting the rear Donkey aflame, unbeknownst to the Pilot - so first they tend to "mysteriously" fall short of the Power-Curve, and then the Cables to the Elevators and Rudder burn through as they go back past the Engine Fire.... According to Richard Bach though, the Rear Propeller is habitually covered with Engine Soot, and so anyone who tries to hang their Shirt over it, while camping on an Airfield halfway through a long Delivery Flight..., the Soot will leave unsightly stains on the Shirt-collar (!). The Dornier 335 was also known to pull the Pilot's Arms off their Torso if they attempted to bail out - after blowing off the Rear Airscrew and the Tailfin..., when they jettsoned the Canopy it literally, "ripped their bloody Arms off, beating their head with the soggy ends" - as it departed the Cockpit.., with their Hands still hanging onto the Jettison-Handles...(!). But strictly squeaking, bilateral Arm Amputation was a feature of the Canopy..., rather than the rear engine, per-se. One grisly segue is that the Seat-Cushions, Armrests, and Head-Cushion on the Do-335's Seat..., were all stuffed with Human Hair (so says the US Smithsonian Institution, who discovered that fact while restoring their specimen of the Marque) - supplied to Dornier from the SS, who collected the Hair from people going through their Extermination Camps...(!). Perhaps, maybe, possibly, the Shades of all the people whose Hair was riding in the Cockpit, stuffed into the Upholstery...; clapped and cheered, every time a Dornier Test-Pilot pulled the Handles while strapped into the Seat and - and thus ripped themselves apart, tearing them limb from Nasty Nazi Genocidal bloody limb in a fraction of a second ! Karma is out there, and it silently stalks ALL they who choose to embrace the idea that, "The End justifies the Means !" Moral of the Story ? Beware of Push-Pull Twin-Engined Aeroplanes, because they notoriously tend towards harbouring unpleasant surprises...; and definitely avoid the ones which feature Cockpit Upholstery stuffed with Human Hair - which was sourced from Crime-Scenes..., perhaps (!) ? Such is life, Have a good one..... Stay safe. ;-p Ciao !

[@Renshen1957]

@@WarblesOnALot The Skymaster pull push design by Cessna had about a 20 year production by Cessna with 2993 (50 of which were military versions).

[@WarblesOnALot]

@@Renshen1957 G'day, Thanks... Yeah, that's the model which put Soot on Richard Bach's Shirts, when he was working as a Ferry-Pilot. Over the years, the Push-Pull Cessnas have had their share of Rear Engines catch fire, surprising the Pilot by failing to deliver commanded Power, often on Takeoff or Climbout. It's a quirky sort of a Failure-mode which only afflicts Push-me/Pull-you installations - apparently as Pennance for having avoided Asymmetric Thrust/Yaw coupling issues in the event of one powerplant failing. The issue is that whereas about 30% of the Chemical Energy in the Fuel comes out as Crankshaft Torque, another 20% emerges as hot expanding Exhaust Gasses while another 50% is being dumped into the Engine's Cooling System..., which on Skyvans means the Cooling-Fins on the Cylinders, Cylinder Heads, and Oil Cooling Radiators are ALL dumping veritable Shitpotsful of Heat into the Cooling Air going through and around the Cowling. And the Thermodynamics of it means that if your front Propeller is putting 200 Hp of Shaft Torque into the Air Column (and by Betz Law then at maximum possible Conversion Efficiency of 0.593...) then 120 Horsepower of Windiness is attempting to dissipate 200 Hp worth of Exhaust Heat plus 400 Hp of heated Cooling-Air.... And, then, in similar fashion to the way many towns draw their Water from a River which is downstream from the neighbouring town's Sewage Treatment Plant pouring Effluent into the Stream...; the Skyvan's Rear Engine is only maybe 10 or 12 feet downstream of the Front Engine, operating in turbulent Flow, sucking all it's Air over the top of the Cabin - from the Low Pressure Area above the Wing Centre Section. I've never aviated in that Price Range, so for me it's never been an issue in real life...; but over all, if I ever had the opportunity, and funding, to buy a Skyvan or not - and go for something roughly equivalent but conventional like a Twin Commanche, Cessna 310 or a Baron ; then I'd be buying one with Wing-mounted Engines, where one can see both of them. Such is life, Have a good one... Stay safe. ;-p Ciao !

[@Renshen1957]

@@WarblesOnALot Well aquantied with most of the information, except for the "soot on Richard Bach's Shirts," LOL, the design had a warning about the rear engine overheating if taxing too long on a hot day. The advice was to check your instrument panel before take-off and do not attempt a take-off on one engine, sound advice for any twin engine aircraft, regardless of engine placement. My point was the design wasn't discontinued, there were variants from a four place smaller version up to a turbocharged top of the line variant, which the French company Rheims continued production of the military version after Cessna discontinued production. You didn't have to visually confirm the model, the rear engine had a unique sound due to its working in the turbulence produced by the front engine. These craft were used by California (my home state) Fire Fighters for Wild Firefighting (forest, etc.) as spotters. Do 335 A-1 was the Luftwaffe's fastest piston engine fighter, amaximum speed of 763 km/h (474 mph) at 6,500 m (21,300 ft) with MW 50 boost, or 686 km/h (426 mph) without boost, and climbed to 8,000 m (26,000 ft) in under 15 minutes on 87 octane fuel, which I presume the test was clean and not fully armed for combat. In the works, Do 635, two Do 335 fuselages, joined by a common centre wing section, similar to the later Twin Mustang, which went as far as a wind tunnel test (proposed recon version) but cancelled 02/45; the Japanese had an interest in the concept again too little, too late. Seems Dornier proposed a version more to your preferrence, a two engine version under the wings in pods after the fashion of the Me 262. The low-mounted wing was unswept, but the large vertical stabilizer and tail surface area nixed the project. Also similar to the Me 262 and the Do 335, Hitler's insisted on interceptors into fighter bombers. The ME 262 if made into the bomber version would have been a Schnellbomber (high altitude bomber similar to Germany's light bombers at the beginning of the war) for the anticipated Allied invasion of France.

[@dallesamllhals9161]

PERFECT! If no one makes lotsa holes in your wings.

[@michaelgautreaux3168]

👍👍 reminds me of the XP-75 Eagle. It had a Allison V - 3420 W-24 ( 2 x V12 1710s). Many thanx Ed. Premium content.

[@HootOwl513]

Thanks. That's the one I was trying to remember. Didn't Northrup try a Double Spinner Pusher? It was in that batch of Swooses and Ass-Enders...

[@jamesengland7461]

They could've incorporated an auxiliary radiator to reduce overheating, and even a thermostat-operated entry duct for it

[@shoominati23]

It's amazing how relatively unknown Stanley Hooker is and the contributions he made through his Supercharger development to securing Air Superiority for the Allies . And that he should be honoured and thanked for this work

[@alexandergustafsson4245]

Love this channel

[@anzaca1]

1:18 One great benefit is that you can use individually less powerful engines. In the case of the Fokker D.XXIII, each engine only had 530 hp.

[@steveshoemaker6347]

Amazing video....Thanks Mr Ed Nash... Shoe🇺🇸

[@davidbrennan660]

It could have won the struggle between the Imperial Japanese Army and Imperial Japanese Navy.

[@USAACbrat]

Pushers overheat and contra rotating props; are not worth the complications and drag.

[@USAACbrat]

Boil off had to be a problem with evaporative cooling. What do you do when you are low on coolant?

[@rosiehawtrey]

Crash?

[@lordniceguy8919]

"The evaporative cooling system depended upon rapid airflow (over it) to work" (7:25) ? Don't all cooling system require an 'airflow' to be able to work?

[@MrAstrojensen]

Yes, they do, but in more conventional designs, the propeller (or in some cases, a cooling fan, like on the FW 190) will automatically provide the necessary airflow to prevent overheating. The evaporative cooling design had the cooling surfaces in the outer end of the wings, outside the direct airflow coming from the propeller, and thus no automatic airflow as soon as the engine was running.

[@johndavey72]

As"Freddie " sang ..."Another one bites the dust !" Thanks Ed.

[@bigblue6917]

R.J. Michell did something similar to this but decided against it because he feared that if the wings got steam hitting cold water would be rather explosive. Martin Baker of course produce the MB 5 aircraft with a gearing system to produce contrarotating propellers but with only one engine.

[@binaway]

The Supermarine aircraft for the Shnider trophy. With the the final schnider design, the s6, the entire surface of the air-frame was the radiator. With the S4 the surface of the floats served as the radiator and with the S.5 the floats and wing surfaces did the job. A single bullet puncturing any part of the air-frame surface would cause a loss of the aircraft.

[@CharlesStearman]

The Supermarine Type 224 (which later evolved into the Spitfire) was one of several prototype aircraft designed to use the Rolls Royce Goshawk engine which used evaporative cooling. However, they all had problems getting the cooling system to work properly, and for that reason, as well as concern over possible vulnerability to battle damage, the Goshawk was abandoned and RR developed the Merlin instead. See en.wikipedia.org/wiki/Rolls-Royce_Goshawk

[@juliancate7089]

Idea for a future vid: Northrop N-3PB.

[@erikhesjedal3569]

Fascinating the difference between the propeller blades. Or should I say, oars

[@brucewelty7684]

oars are blades.

[@HootOwl513]

Thaks for saying Ki right. It's KEY to good pronunciation. I was told by an internet sensei the Katakana Letter Ki was shorhand for Airframe + Number. As used by the IJAAF. The IJNAS Typed thier aircraft by a code that indicated Role, Iteration, Manufacturer and type number. A6M5 = Attack [fighter] Sixth in series/ M = Mitsubishi/ 5 = Fifth revision.

[@robertshields2066]

I wonder if instead of two inline engines being used, how about using a rotary engine up front and an inline engine behind it. That way the length of the aircraft could be greatly reduced and also needing one cooling system as the rotary engine would be air cooled, just an idea.

[@ripvanwinkle2002]

Fun Fact~ my Mother also gave ME the code name of "Rob"

[@icewaterslim7260]

Lol . . . luv the header. You might ask Lockheed what could go wrong with evaporative inner-wing mounted coolers. The P38 though the "H" model used the system for the 2nd stage turbocharger inter-cooler. Well it worked so good at the high attitude for escorting the bomber missions in Europe that it either froze the system up or required green pilots to adjust manifold pressures and usually at the inconvenient times of combat. . So Lockheed's designers clung to the system for it's lack of drag benefits until facing the inevitable "devolution" to a conventional radiator and scoop in the "J" and "L" models but still got canned from it's quest as the high altitude escort for the 8th AAF B17 and B24 missions into Germany.. . Considering Japan's drafted inadequately trained workforce left to the manufacturing after the manpower drain in Manchuria, China and all over the Pacific their holding tolerances on long V12 crankshafts just might go plenty wrong as well

[@PaulieLDP]

A very interesting design.

[@johnlander4635]

It had evaporative cooling.... Woah woah let's stop there, fella.

[@MrCenturion13]

I have a model of this somewhere...

[@gort8203]

The impracticality of the evaporative cooling system did not invalidate the twin engine configuration. Conventional heat exchangers could have been used (as the Do-335 did), and even though the airplane would have had more drag it would still have more speed and a greater climb rate than an airplane with a single engine.

[@LV_CRAZY]

After long research and development interest in the technology evaporated

[@doankhang9496]

A very beautiful aircraft!

[@soldat2501]

Sounds like a great idea for a plane that no one would shoot at.

[@mikepette4422]

oh wow never heard of the French plane good job digging that up

[@rubiix2889]

The Ki-61 double caked up on a thursday afternoon

[@comentedonakeyboard]

Kawasakis motorcycles proved to be more lethal.

[@leoa4c]

The problem with having 2 engines in the fuselage is... having 2 engines in the fuselage. You are left with little space for anything else. Combined with a large portion of the wing used for cooling, there will not be a lot of fuel to feed the 2 engines for long. Aerodynamically, it is a fantastic, very tempting idea. Just not well suited for fighter aircraft with range needs.

[@SoloRenegade]

the Supermarine Thompson racers also used such a cooling approach.

[@Eric-kn4yn]

Self sealing cooling system in wings. As was fuel tanks

[@aidinmcinerney6512]

Self sealing fuel tanks work by having an outer layer of rubber that would react with the gasoline and basically melt over the hole, so it wouldn't be able to work with coolant, let alone highly pressurised steam

[@niceguy391987]

Imagine a Fairey Gannet in skinny

[@stevetournay6103]

That airframe with a paired turbine...hmm!

[@jebise1126]

i wonder how useful is machine gun that needs to shoot through 2 propellers... must be quite a drop to volume of fire

[@trooperdgb9722]

Less than we would intuitively imagine I bet! Even with two props I suspect the amount of time a blade is in front of the muzzle is far less than our puny human perceptions of "time" would have us instinctively think... Perhaps we have a mathematically inclined person on here who could try to do some calculations.... RPM combined with blade width and so on... to produce a rough figure of what % of each second (or prop rotation) the guns would be "blocked" ....

[@shaider1982]

as a contrast: in a Curious Droid video, the B29 also had cooling problems for the engine so it was sent to NACA (NASA's predecessor) to check on how to improve the cooling. both the cowling and the engine were redesigned and were simple compared to the changes here.

[@Ob1sdarkside]

Didn't change the cylinder height to allow for more cooling as well? That was a great vid

[@shaider1982]

​@@Ob1sdarkside yup, they did enlarge the cylinder head as part of fixing the engine.

[@PaulP999]

Don't forget the Fairey P24, a double opposed motor like a long Napier Sabre in which each "slice" of opposed banks drove independently one contra-prop. You could actually shut down a bank and its prop for economic flying. It was too late and its potential future was pretty much taken up by the Double Mamba turbo-prop.

[@simonchaddock4274]

Evaporative cooling system? Surely it would be better to describe it as a condensing cooling system. An evaporative system uses the heat of evaporation of water in air but then disposes of the moisture rich air. The water is continually used up. A condensing system boils the water into steam and turns the steam back into water using condensers so it can be reused. No water is lost. As Kawasaki and many others have found it is hard to get a streamlined air cooled surface condenser to work well in a plane.

[@traumgeist]

Good thing we let the British name our fighter planes for us. Or we’d have planes named like P-51 Dave etc.

[@anzaca1]

2:30 Ah, the Ki-61. When a Japanese aircraft designer FINALLY understood that you actually need armour.

[@stevetournay6103]

Heinkel 100 was a beauty. I wonder what influence it had on the almost equally attractive Ki61. Ki64 is fascinating.

[@jonathanstein1783]

Planes Of Fame in Chino, CA, has a very nice wooden mockup of the HE 100. Built by volunteers, I believe.

[@lookythat2]

I have often commented that the Ki-61 "Tony" did not resemble either the Messerschmidt or any of the Italian (ostensibly why it was called the "Tony") fighters, but rather, the Heinkel He-100, especially viewed in profile. Basically, if you hang a radiator under the He-100, it is almost identical in profile to the Ki-61. What I did not realize until watching this video was the direct connection between the He-100 and the Ki-61's designer. Thank you for reporting that no fewer than three He-100s had been sent to Japan, for study by Kawasaki. I appreciate the great information you're putting out. Good job!

[@stevenhoman2253]

Dornier with their Phiel got it right, and went like stink, it could outrun any prop fighter of WWII, and even had an ejector seat, and a jetisonable lower vertical stabiliser for belly landings.

[@neiloflongbeck5705]

It had an ejection system that was as lethal to use as remaining for the crash. It needed a longer runway for take-off and landing due to the rear prop and the ventral fin.

[@mbryson2899]

IIRC, it had some challenging airfield requirements but otherwise was a solid performer. Too little, too late, though. Zero kills or engaged combats according to the sources I've seen. Still a beautiful aircraft.

[@johnlander4635]

And didn't work.

[@neiloflongbeck5705]

@@apis_aculei except in the Pfeil it had a nasty habit of not being able to be operated as the canopy fe Ease had ripped the pilot's hands off.

[@Astrawboy_NameAlreadyInUse]

The tandem engine layout was not the invention of French engineers, some preceding designs exist in paper boards. Ki-64 is likely based on a design called AT-27. AT-27 only exists on a paper, but it's a result of a future-designer competition in a pre-war magazine. Meaning it's unlikely the tandem engine layout is brought from VG10 nor latecoere 299A.

[@comacollosasa6282]

Well now I’m wondering who got the scrap

[@mgbrv8]

The earlier French twin engine twin prop design was done by Bugatti

[@stevetournay6103]

That's the prewar deMonge-Bugatti 100P, yes. Built as a racer but intended for development into a fighter. Powered by a pair of Bugatti T50B car engines regeared to turn coaxial props. The original never flew, but survives today in the EAA museum in Wisconsin; a replica built about twenty years ago did fly but tragically crashed not long afterward killing the pilot. The basic design would have made an interesting jet trainer.

[@mgbrv8]

Yes the crash was a very sad tragedy I followed the build for years

[@Clonefiles]

They thought to combine a couple of cutting The Ki-64 🤑🤑

[@runem5429]

Evaporative cooling system...hmm. I guess the need for surface area and airflow means it's not what I initially thought, it doesn't throw steam overboard for cooling, but rather has some form of condenser to shed the heat and return the coolant to liquid form...so, sounds like it's "just" something like a heat pipe cooling system, maybe not passive in the same way..? I'd like to know more. I wonder if such a system couldn't simply bring some extra water and emit steam to patch up the moments of excessive heating while taxiing or climbing 🤔

[@clintfalk]

Its the same method used for commercial HVAC air conditioning, where the flow of water can be used to cool or heat an area, depending on which path it is routed. Notice the plumbing hanging from the ceiling of many commercial and institution buildings? That isn't necessarily the fire sprinkler system. It is likely routed to an HVAC unit on the roof, or in the case of a large instituiton, a separate building housing a massive evaporator/condensor system.

[@martentrudeau6948]

The German Dornier Do 335 Pfeil ("Arrow") heavy fighter had 2 engines and was very fast, and Captain Eric Brown, British Royal Navy officer, flew it and liked it. -- kzbin.info/www/bejne/aHuuoH-CnLZnrdE -- Although it needed further development to perfect its ejection seats.

[@robertcampbell6349]

Excellent video.

[@johnlovett8341]

Awesome learning experience for me as always. Yet another thumbs-up from me to Ed Nash. I'll keep hounding you to re-do (re-record) the NA-Grumman mix-up in the intro to the NA P-64. You don't make mistakes like that, at least until NA-Grumman mix-up. And with your awesome factual and analytical record comes great expectations. With your documentary superpowers come great responsibilities. I certainly could not do what you do.

[@EdNashsMilitaryMatters]

Alas, cant edit it once it's up on youtube very much. I've cut the section where I said they built the landers, but that is all I can do with it.

[@onkelmicke9670]

Do 335?

[@MrDino1953]

No mention of any noise problems from the contra-rotating propellers?

[@SheepInACart]

It wasn't a problem in this design/era. The open exhaust stacks of the v12 engines made far more noise than the conventional propeller, and most of the noise of the counter-rotors at these power levels (

[@loumencken9644]

What is "Thunderscreech" in Japanese? Are all contra rotating prop designs unusually loud, or is it only when they are driven to speeds where the tips exceed Mach I as on the Thunderscreech that excessive noise becomes a problem?

[@SheepInACart]

@@loumencken9644 Language only really works in context, my best guess would be 雷鳴 (Raimei). Its a word that literally translates to both thunder and ringing... but also snow. But you don't normally translate a proper noun. Noise wise the supersonic tips was why thunder screech stands alone in purely disturbing noise levels, but things do get a lot more complex with counter-rotors, including the frequency of blades passing. A normal 2 bladed Cessna 172 doing 2200rpm at cruise will pass over the two cowling vents 146.67 times per second, which with the apparent volume curve of human hearing means the 4th harmonic appears the loudest dominating noise. A counter rotor with 2 rows of 4 blades at the same RPM will be 293.33 passings per second, putting the much greater intensity second harmonic within the same frequency range. Finally is application, counter-rotors are more expensive, complex and heavier than a single rotor, so just like a helicopter people generally only use them when they cannot use more conventional means. This means that once again even if the same noise level could be reached for a given power level, diameter ect, the noise of a propeller with that kind of blade loading, total power output ect is normally already very high, while most conventional propeller applications aren't.

[@1joshjosh1]

Hello Rob.

[@guaporeturns9472]

Cool

[@mickvonbornemann3824]

The Italians did it too, with a racer

[@life_of_riley88]

Evaporative cooling sounds absurdly complex for a WW2 fighter. Like some the Germans would come up with. . .oh wait.

[@shannonterry4863]

Interesting concept, would never be acceptably operational given it's complexity as a combat aircraft. Jet power changed the rules for everyone after this approach to aircraft power plant design.

[@thederangedwartomato5383]

Ed Nash! Who the Hell are you? What the Hell are you? Where the hell do you come from? How the Hell do you know so much? THANKS for the Videos!!!!

[@guidor.4161]

A lot more slender than the Do 335

[@Caseytify]

For all the concern shown for agile fighters, US designs have historically been less maneuverable than their opponents, yet the Navy/USAF have been victorious in every war since WW2.

[@alan-sk7ky]

XB 42 Mixmaster anyone?

[@marcussmith2868]

censored by youtube?

[@RemusKingOfRome]

All these single fusilage , twin engine designs look so awkward. Not really the dog-fighter type .. and no space to put anything.

[@xkgbciax5286]

How to get more speed from a tech that was close to max was really the only point, Italy The Ca.183bis 1,250 hp (932 kW) Daimler-Benz DB 605 in the nose driving a six-bladed contra-rotating propeller, augmented by a secondary piston engine behind the cockpit driving a Campini compressor, expected to furnish a 100 km/h (60 mph) boost from jet thrust

[@jaws666]

Kawaski Heavy Industries

[@Eric-kn4yn]

Safety too I engine will get u home

[@brucewelty7684]

Another example of a pipsqueak country trying to produce big stuff. All Hail Emperor Doug for building the pipsqueak into a world power.

[@pavelavietor1]

AMERICA NEVER OCCUPIED 😂 NIPON 😮 , THE USA DID . YOU CAN PROVE ME ERRONEOUS IF YOU CAN. SALUDOS PAVELAVIETOR1 VISIGOTH1 IBERIAN1

[@pavelavietor1]

@Cancer McAids AMERICA , FEMALE VERSION OF THE NAME AMERICO VESPUCCI, A MEMBER OF THE CASTILLIAN EXPEDITION BY ISABEL DE TRASTAMARA . saludos IBEOAMERICA , Gracias a DIOS monto a todo

[@isleifoterogarcia4478]

@Cancer McAids ...but they keep parroting "Americans... Americans ¨... at nauseaum. That's why. America is a continent, no less.