Inside The Chieftain's Hatch: Ho-Ro

[@IFear_Naught]

Those "mini engines" sticking in front of the engine are mechanical injection pumps, used mainly on old diesels, superceded by electronic. Were also rarely used on petrol engines, to bridge the caburated and EFI ages.

[@Rom3_29]

Mercedes’s and Cummins diesel engines has same setup.

[@jeromethiel4323]

@@Rom3_29 Ditto for early VW diesels. My Rabbit had a 4 line pump that looked a lot like that.

[@paoloviti6156]

​@@jeromethiel4323 a dumb question: I've been driving for years both the VW Beatles and Combi and were all gasoline engines. Only in the late sixties it started to produce diesel engines. To what version you are referring??

[@jayffemt]

A multiple-unit injection pump. A lot of diesels used them. Just unusual in where they're placed.

[@jeromethiel4323]

@@paoloviti6156 78 VW rabbit, not a bug.

[@soonerlon]

Take it from a retired mechanical engineer, the 2 devices you were looking at were fuel injection pumps for the engine. Talk about tight packaging and the absolute fact they didn't talk about tanks very much from their axis ally....

[@tantoismailgoldstein6279]

That's so they could reprime that buck from inside. Who would love to jump out and do it while trying to get away.

[@danielstickney2400]

Years ago I read an account of an Australian constabulary unit's experiences on postwar occupation duty in rural Japan. They quickly learned that they had to patrol in jeeps because there wasn't one bridge in their entire operations area capable of carrying the weight of a six ton Staghound armored car. It's hard to develop much of a tank arm when you can't even deploy them in your own country. As for the Aussies this actually worked out for the best because their role quickly evolved from occupation to befriending the locals who were pleasantly surprised when the terrifying "foreign devils" turned out to be a bunch of smiling young men in jeeps handing out relief supplies and candy.

[@Grimmwoldds]

FWIW, it's a weird cultural thing as well. Anglo soldiers tend towards informal/familiar speech and behavior, and they're forgiven that because "they're foreigners who don't understand". But due to the culture of Japan, many Japanese unconsciously accept that informal/familiar and start acting as if you really are more than a stranger(at least at the level of acquaintance, if not a friend). As long as you don't put yourself in a formal address required situation(like, "I had sex with your daughter") it's pretty easy to do shallow social interactions like what we now call "hearts and minds" operations.

[@ivancho5854]

​@@GrimmwolddsExtremely interesting. Thank you very much for explaining the nuances. 👍 All the best.

[@MGMeza]

I love reading historical accounts from the WW2 era if you have a link or name of the book of the Aussie I would love to read it myself! Thank you for sharing 🎉

[@Chan-Lin-Tao]

The Japs have not forgotten Hiroshima and Nagasaki. Believe me, they are not very friendly with foreign devils, it's just resignation, not friendship. Friendship is won with respect, not with atomic weapons. Do you understand what I mean?

[@danielstickney2400]

@@MGMeza It was an article in "Army Motors" the Military Vehicle Preservation Association members' magazine.

[@izumishion6267]

Huh. Incredible. I had no idea that a HO-RO actually survived. Definitely gonna be checking this out. Thanks for showing this off.

[@Dargesh890]

I've seen it at that museum. It is really interesting to see, and I love that the battle damage is still very visible. That whole museum has some amazing vehicles, I highly encourage you to check it out. An almost fully restored Panzer 1, and a few other rare vehicles are in there as well.

[@timhoran3887]

Been there and seen that tank very cool..the museum is awesome ...

[@YankeeMugwump]

@@Dargesh890 90% of all the vehicles at the American Heritage Museum are drivable, including the aircraft.

[@Dargesh890]

@@YankeeMugwump I remember hearing that when I was there. The museum is a really good one!

[@stuartbennett7614]

Fuel pump similar to a tractor

[@davehopkin9502]

The contraption at the back of the "cab" is the fuel injection pump, used to correctly time when fuel is injected into the cylinders, it will be mechanically connected to the engine crankshaft, which turns a cam shaft, followers on the cam open and close the fuel valves to release a pulse of deisel to the cylinder at the right time.

[@larryfontenot9018]

Direct fire for a divisional SP artillery piece makes sense if you stop and remember that most Japanese tanks were light with small caliber anti-tank guns. A large caliber assault gun is really useful when the tanks around you are armed with 37mm, 47mm, or low velocity 57mm main guns. The Type 97 Chi-Ha only had between 8mm to 25mm (on the gun mantlet) of armor, and it was classed as a medium tank by Japan.

[@johnludmon510]

Yes as you say most Japanese tanks were small lightly armoured and not very well armed a direct fire mobile 15 cm gun would be appreciated. That and the Japanese industrial capability was stretched to the limits so you sometimes got a cobbled together vehicle that was not ideal but was better than nothing. You can’t expect a Hummel or a sexton if the base vehicles aren’t available.

[@viandengalacticspaceyards5135]

Yes, also most Japanese experience was against Chinese, not exactly a hi-tech army. So driving up close to the fight and shooting straight at positions might well have been a good option. The armor may also have been good enough for this, if you don't hang around until they bring something big enough into position. What I did not get, was there a loader or did the commander or gunner handle these big shells from that odd rack on the back?

[@obsidianjane4413]

@@viandengalacticspaceyards5135 They had a 2 loaders that hung onto the back half of the vehicle where ever they could. It was very much more of an assault gun than a SPG.

[@BPo75]

@@obsidianjane4413 Assault guns are a subdivision of SPGs-

[@obsidianjane4413]

​@@BPo75 Context here is self propelled field artillery, vs direct fire support guns. Check your pedantry.

[@JasperFromMS]

Yep, those are mechanical injector pumps. If you look closely inside the engine compartment, you may notice coils and zigzags in those lines so that they are exactly the same length.

[@thomascampbell4730]

When I worked at the Air/Ground Museum in Quantico I was very eager to tackle the restoration of this vehicle. I had spent thousands of hours on a ZIS-3 artillery piece and an SU-76. Restoring the SU-76 was a great deal of work but when I was short-toured and PCS'd the hull and gun were blasted, painted and restored. The engines had been torn down, restored and painted. We decided to "pickle" the engines (2 flat-head, 6 cylinder, gas engines in tandem) because it had thrown a rod in the forward engine due to holes in the oil pan (probably caused by the vehicle running over a mine). I'm disappointed that no one tacked the restoration of this Ho-Ro since it is probably the only intact specimen of the breed. I have wondered for 30 years what became of this Ho-Ro and I'm delighted that she is now in a climate controlled environment.

[@richardbell7678]

At 7:12, as the cotter pin is usually a softer metal than what it passes through, a likelier expedient method of removal is to shear the cotter pin as the track pin is pounded out with a hammer and drift.

[@TheChieftainsHatch]

Hmm. That could be so as well. I had not considered such a possibility.

[@truracer20]

@@TheChieftainsHatch it's an old mechanics trick. Same thing with cotter pinned nuts with rust issues, just do what ever you have to do to the pin in order to get a socket or wrench on the nut and the nut will shear the cotter pin as it unscrews.

[@SnakeyesYT]

I love this museum. It’s in Massachusetts and it’s a 10/10. A lot of the people there are volunteering veterans and everyone is super nice.

[@erikgranqvist3680]

About the pin securing the tracks: caught pinsamt that split apart have been common on various farming equipment thru the years. At least on a farm, doing a field repair out on a field they can be something that creates opportunity to be inventive with strong language.

[@TheCoyote808]

Mechanical fuel injectors/pumps are your mystery Mini engines. You'd find those on diesels all the way through the 80s when modern tech allowed those comtraptions to be fitted directly to the injectors or to a series of rails. Fairly advanced tech for the 40s in a diesel. Heck, it looks very similar to some of the pumps I've seen on CAT motors from the 80s and 90s except they're mounted remotely.

[@adirondacker007]

3406-B comes to mind.

[@zschade27]

Added that museum to my bucket list thanks to your video and glad to say I made it there last august. Was amazing!!!

[@dexionsgamingcorner310]

It's fantastic and worth the Trip. If you like tanks, you will love this place. They actually have an Abrams, IS-2, Scud Launcher... the place is huge.

[@TheMoistestNugget]

I’ve spent more time than I care to admit looking at footage and animations of the bell cranks suspension on ha-go and your explanation is what made it make sense 😅

[@pacificostudios]

Respectfully, the Ho-Ro might have been a very powerful weapon in the Japanese Army because Japan was just putting 47 mm guns into their tanks in 1944. Also, Japan had relatively few field radios, so indirect fire wasn't going to happen much, if ever. My guess is they planned to keep this artillery piece behind the tanks, firing ahead of them as they advanced. On the plains of China, no one was going to be killing the enemy from 2000 meters, but also not fighting at point blank range.

[@JohnDoe-vm5rb]

This is one of the most interesting videos you've done chieftain, explaining your educated guesses and the different designs to other tanks.

[@osmacar5331]

old tech is great for my education into mechanical engineering, once again, nick teaches me more about tanks and little things engineering wise than anywhere else* *excluding the tank museum.

[@russwoodward8251]

The Japanese armor of the day tended to shatter over time. On the Aus Armor page they are digging up Grant tanks of a similar age with no shattering. Thanks Chieftain and WOT!

[@jimmylight4866]

Lack of molybedenum. It gives steel elasticity. Late German tanks do not have enough either.

[@MilBard]

The US Navy technical reports on Japanese tank armor was that they were high hardness to get ricochets from small arms, antitank rifles or low velocity 37mm cannons. The Japanese made high hardness AP shells for there 47mm to deal with Soviet armor which had similarities in terms of hardness. First generation cast Sherman’s proved to be fairly vulnerable to the 47mm under 500 yards as a result.

[@alm5992]

I am so glad that throughout the wars we have had some out of the bunch that thought "we need to keep this to study", and even more glad that a few thought "for future generations to see", instead of scrapping them.

[@sadwingsraging3044]

13:35 I see a logical reason. If the one closest to the rear was horizontal the dirt and rock tracked up is far more likely to trap between the rods and get channeled into the spring as it falls verses hitting the top rod and getting shed to the side. Pretty simple actually. That's a rock funnel into the spring they did away with by making it vertical to the falling dirt and mud. Plus that configuration is far stronger being compresed into the spring at the geometry it moves going in on that pivot.

[@dragomirw.844]

Type designations actually had two different possible systems - some were named based on the year of the current reigning emperor as you mentioned, but sometimes they were done based on the last two digits of the traditional Japanese calendar year, which has a year 1 in 660 BCE. This just adds to the confusion of the designations leaping around.

[@SnakebitSTI]

I think Heisei 44, kōki 2604, and Gregorian 1944 all overlap? Anyway, breaking it down: 四式十五糎自走砲 ホロ. 四式 (Type 4) 十五糎 (15cm) 自走砲 (self propelled gun) ホロ (SPG B). In US terminology, it would be something like "150mm Howitzer Motor Carriage M1944 SPG-B". For another example, "chi-ha" is short for "medium tank C".

[@dragomirw.844]

@@SnakebitSTI In 1944 the reign year was Showa 18. Heisei didn't start until 1989?

[@SnakebitSTI]

@@dragomirw.844 Ah, not sure why I wrote Heisei instead of Showa. And I have no idea how I arrived at 44 years.

[@ScottKenny1978]

More fun, each time the Emperor changes they restart the year count. The Type 30 and 38 rifles are from the Meiji era, Meiji 30 and 38 (Meiji 1 is 1868, so 1898 and 1906). The type 12 HMG is from the Taisho era, 1920s. And then the Type 44 rifle dates from the Showa era, when they mostly went to the "years since start of Japanese Empire" way of counting, which started somewhere around 600BCE.

[@davidjernigan7576]

The injector pumps are most likely run off the cam drive at one end of the engine which is why they are located where they are

[@DaGamesPlaya]

This thing looks like it wouldn't be out of place in a Metal Slug arcade game. Like the whole design with the bolts and rivets everywhere, the top heavy structure, semi-exposed crew, the sheer cartoony look of the thing :P

[@OOZ662]

Metal Slug is a Japanese-developed game "parodying" a lot of World Wars and "modern tech (i.e. jets) that looks like it was made in the 30s" equipment, so I'd say that's pretty accurate.

[@JackDrinkn2DollarJim]

Since most Japanese tanks had smaller caliber weapons it may have been for use against fortifications and dug in infantry.

[@Dargesh890]

That's what I was thinking. Japan really didn't arm their tanks with much

[@SnakebitSTI]

Yeah. We might be very tank obsessed looking back at WWII from the 21st century, but tanks were just one piece of the combined arms puzzle. Lots of weapons that were useful against tanks were not specifically intended for use against tanks.

[@taistelusammakko5088]

According to steven zaloga, curiously enough he lists ho ro as a tank destroyer

[@mellowcloud1359]

@@taistelusammakko5088 Could you imagine trying to line this thing up at another tank lmao

[@janwitts2688]

The Japanese used a log for elevation fired a smoke round and took radio corrections from forward observer they were rather well organised

[@gashnal]

KZbins algorithm just sent this to me, I was just at that museum it was a blast and the staff are all rather knowlegable I got to have some really great conversasions about several of the pieces on display.

[@paulfrantizek102]

The spring set up is similar to the suspension on a Citroen 2CV (which accomplished largely the same with a hydraulic cylinder).

[@cheesenoodles8316]

This is a rather rare Japanese SPG, to find one in a states side museum is nice. Ruff condition but mostly there.

[@renegadeleader1]

Talking with the docents and curators at the museum, they can't restore anything on the Ho-Ro per instructions from the Marine Corps who lent it to the museum.

[@drderper]

It is very curious to see a Welin breech gun on an armored vehicle. I always like seeing close ups of them

[@oscarjosefsson9300]

Finally after more than 15 minutes of waiting we get to the track tension! This is clearly the high point of every tank video! ❤ I also want to on a more serious note say a big thank you for bringing this to us! 😊 And cool in a way that it is basically like a research mission as well where we can all take part!❤

[@i_nameless_i-jgsdf]

Finally a video on the Type 4 Ho-Ro ! It doesn't seem to be anyone doing a detailed video on this thing. This makes me wish that they send you to Japan and do more video on their vehicles especially the another only surviving Type 3 Chi-Nu or the only functioning Type 89 I-Go medium tanks. Or even videos on the Type 61 MBT which they should allow you to go inside and filming since it is retired for at least 2 decades now, not sure about Type 74 eventhough it is slowly being replaced by the Type 16 MCV.

[@erikgranqvist3680]

Also, the thing you didn't know for certain what it is: your guess are correct - it's the diesel injection pump. It's a bit of odd looking compared tol for example, a 60's Land Rover.

[@alastarrio]

from what ive seen and read, especially in hara's own books, in the driver's position the center lever is a parking brake, the two for each side are individual brakes and clutches, they have a ratcheting mechanism with a button to release on top, and then theres the levers for the 4 speed transmission and directly behind that for the 2 speed auxiliary transmission, essentially a high/low range, giving it 8 forward speeds and 2 reverse. those units on the engine firewall were injector pumps theyre driven on gears off the camshaft.

[@teamidris]

They’ve put the diesel injector pumps in the cab so they are easy to bleed under fire. The thought being bad fuel. Only way to clean the filters is to disassemble and unfortunately let air in, but the high pressure pumping pistons won’t pump air.

[@jeffreyplum5259]

The direct fire only mode is a feature, if one looks at how small Japanese tank guns were generally. These things cracked anything too tough for the popguns on the tanks to handle. .Eggshells armed with Hammers

[@Ghostmaxi1337]

The 15 cm Krupp 05 gun the Ho Ro has had both He (with more than 7kg filler) and Anti Concrete/Anti Tank rounds available, it can make short work of most, if at least a mobility kill, because it will shredder every tracks it encounters.

[@yeetadog]

@@Ghostmaxi1337 if it actually manges to get an accurate shot off before the real tank gun mounted on whatever it is facing does

[@Ghostmaxi1337]

@@yeetadog You are thinking wrong of tank engagements. You dont take thw rarity nor taktics such as hiding/cover into account. Also just because its a somewhat low velocity gun, doesnt mean it cant get a good first round out, there are more things to considder.

[@yeetadog]

@@Ghostmaxi1337 from an ambush position, maybe, in any other case, this heap of junk is screwed

[@pauladams286]

Thank you. It is always good to see Japanese armour getting some coverage, as it is often overlooked. In fact, the whole of the Pacific and Far East are generally overlooked due to the emphasis on Europe and North Africa.

[@shawncarroll5255]

Thank you very much for the explanation on how the suspension work. I've seen it for years, and was never quite sure what was going on. Now it makes sense. I've had cotter pins on a heavily used 6 and 1/2 horsepower rear tined Sears rototiller. I use it in clay soil. Getting both wheels off can be lightly annoying, especially if you've just discovered the clay is too wet 5 in down to properly tine, but it's gooped onto everything. That's just two cotter pins...

[@mattf3623]

That museum is epic!! So glad I'm only 40 mins away 😊

[@aidanacebo9529]

I've always had a soft spot for Japanese armor, simply due to the scarcity of it. we just don't know enough about it to be certain in a lot of regards.

[@georgesakellaropoulos8162]

Japanese armor has many soft spots lol.

[@MrCantStopTheRobot]

WW2 Japanese armor is quaint.

[@ditzydoo4378]

Hi-Ho, Hi-Ho it's off the Ro we go... 0~o sorry, low hanging fruit and all. ^~^ 20:22 mark, these are indeed two sets of mechanical fuel injectors. A like type fueling system is used on my grandfather's Ford 4000 diesel tractors engine.

[@barryborton6732]

The accelerator bank looks a lot like a modern diesel injection system. I've seen similar on modern Diesel engines

[@bverheijden]

@♦20:30. Those fuel injector pumps, what I like is that there 2 units, 1 for each bank of cylinders. Probably they had a 6 cylinder version and just decided to keep it simple for engineering. Those things were still in use wit truck diesels in the 90's.

[@zefriend3]

Hey Chief, 20:30 is a high pressure fuel pump with cam supply, governor etc, direct supply to the injector head via those metal hoses.. BMC used the same on their 2.2s... Mad to put it there though.

[@Floopflorm]

The Heritage museum! I love that place it is gorgeous in Hudson, Massachusetts. Very fun and gorgeous layout.

[@marclagalle1486]

Maybe like an M113 A1 - main steering levers and pivots. And yes - injector pumps. Would have had a cover.

[@robertmcnally9305]

I’ve been to the American Heritage museum in Hudson for their tank Demonstration weekend. I loved it

[@ROBERTN-ut2il]

The Type 4 Ho-Ro (四式十五糎自走砲「ホロ」) is an open-topped self-propelled gun with a short-barreled 150 mm howitzer, based on the Chi-Ha. Being pressed instantly into service on its creation, a dozen or so were shipped to the Philippines together with the newly formed 1st Self-Propelled Artillery Company. While it did see combat with several confirmed Sherman destructions, it was effectively used in close-quarter combat rather than as an artillery piece, firing at Shermans at 100-200 m range in smokey and low visibility scenarios, and repositioning on each shot. Arriving in Dec 1944, the last Ho-Ro squad served until knocked out in Mar 1945 with the remainder of the company fighting until the end in the mountains as regular infantry. Armour type: Rolled homogeneous armour Armour Front Sides Rear Roof Hull 12 mm (80°) Front glacis 15 mm (63°) Joint plate 25 mm (37-64°) Lower glacis 25 mm (28-36°) Top Left 25 mm (25-26°) Top Right 20 mm Bottom 17 mm (70°) 20 mm (4-69°) 8.5-12 mm Turret 25 mm (15°) 20 mm (0-11°) N/A 12 mm 150 mm Type 38 Mode Capacity Vertical Horizontal Arcade 28 -10°/+20° ±5° Ammunition Penetration statistics Ammunition Type of warhead Penetration @ 0° Angle of Attack (mm) 10 m 100 m 500 m 1,000 m 1,500 m 2,000 m Type 95 APHE APHE 38 37 35 33 31 31 Type 92 HE HE 55 55 55 55 55 55 Shell details Ammunition Type of warhead Velocity (m/s) Projectile mass (kg) Fuse delay (m) Fuse sensitivity (mm) Explosive mass (TNT equivalent) (kg) Type 95 APHE APHE 290 36.1 1.2 19 2.6 Type 92 HE HE 290 36 0 0.1 7.02 As part of the technology sharing scheme between Nazi Germany and Imperial Japan, the Japanese Army delegates were shown many German vehicle designs. These included the Grille series of self-propelled guns. This is what the Japanese Army Technical Bureau would base the Ho-Ro on. Like the German Grille, the Ho-Ro was based on an already existing tank chassis. The chassis chosen was that of a reinforced Type 97 Chi-Ha. Production of the vehicle would fall to Mitsubishi Heavy Industries.The armament of the Ho-Ro was the Type 38 15 cm (5.9 in) howitzer (三八式十五糎榴弾砲 Sanhachi-Shiki Jyūgo-senchi Ryūdanhō), which was also based on a German design by Krupp. The gun had previously been withdrawn from service in 1942 as it was deemed outdated, being a 1905 design. The surplus guns were brought back into service and mounted on the Ho-Ro. The ammo of choice for the Type 38 gun was the Type 88 APHE (Armor-Piercing High-Explosive) shell. It could also fire HEAT (High-Explosive Anti-Tank) if necessary. The gun was capable of firing one of these 36 kg (80 lb) shells at 282 m/s to an effective range of 6,000 m (6, 542 y). Ammunition was stored in a container on the engine deck. The 15 cm howitzer was mounted behind a 25 mm (0.98 in) gun shield and had a limited traverse arc of 3 degrees left and right. It could elevate 20 and depress 10 degrees. The gun shield was the only real armor on the vehicle. The 6 crew members of the Ho-Ro were completely open to the elements, small arms fire, and shrapnel. The vehicle also had no close-defense machine guns. Mitsubishi produced a small number of these self-propelled guns, a meager number of 12. The Imperial Japanese Army rushed these into service during the last months of WWII in the Philippines Campaign. They served in batteries of 4 with the Japanese 14th Area Army. Remaining units were stationed in Okinawa during the American assault. However, they were grossly outnumbered by the United States’ own artillery units.

[@streetgato9697]

Thank you for sharing this well-detailed info.

[@PKLAGOON]

戦闘室上面左側には九七式車載重機関銃が装備されていました。託架が残っている筈です。

[@comentedonakeyboard]

Self propelled Caronade perhaps? Would have made sense for bunker busting, like the original (short barreled) StuG.🤔

[@r.gilman4261]

So we're looking at a SU-152 light, seems to make sense that's the job it could do. I suspect the Japanese were hoping to get more utility along the lines of the 15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B, but were in a bit of a hurry to get something.

[@comentedonakeyboard]

@@r.gilman4261 yes, something like this.

[@ivancho5854]

19:59 The term you were looking for is "sections of angle iron". Loved the video. 👍

[@punet-bis-32t]

It's a pity that Japan doesn't have a tank museum, so detailed information about tanks is not preserved.

[@RohanGillett]

There is the Tsuchira Tank Museum in Ibaraki Prefecture with some old stuff. And you can also see tanks at the Japan Ground Self-Defence Force Public Information Center in Saitama Prefecture, which isn't a true museum but it does have modern Japanese tanks.

[@JuffoWup78]

I suspect the second set of tillers for steering may be used depending on what the tank is doing. IE, one for steering while in placement for aiming while the other one is used while driving

[@diestormlie]

Ohh, that could be it. You'd want finer control when maneuvering for aiming, I reckon.

[@danielstickney2400]

Caterpillar tractors used separate levers and pedals for steering clutches and brakes right up into the 1970s. I don't know what the supposed advantages of separating the steering clutches and brakes but it could be as simple as that. I don't know why they persisted with separate clutch and brake controls when other makers used one lever to operate both the clutch and the brake and you aren't supposed to touch the steering brake until you have that steering clutch fully disengaged. I do know that with two levers, two pedals, one hand on the blade control and a decelerator (as opposed to accelerator) pedal you have to be on your game to operate and old clutch/brake cat properly.

[@fredbecker607]

Later, they were able to open the 3 hatches. they found three Japanese soldiers waiting to attack the American devils. After a short battle, the Japanese drove off in victory.

[@davidbrennan660]

Until a track was shed due to lack of recent track tensioning.

[@aidanacebo9529]

certainly gave me a hearty chuckle, that one. good on ya!

[@JoshuaC923]

😂😂😂

[@Dargesh890]

So THAT explains why I heard Japanese voices when I was at the museum. I thought they installed speakers inside as part of the exhibit!

[@davidhollenshead4892]

More like they found the remains of a Japanese mechanic who got trapped inside...

[@bobbyfostore1455]

What an outstanding hands on explanation. Great Job Sir.

[@MGB-learning]

Outstanding video and presentation.

[@teruakiarai4086]

本車に搭載された照準器は直接照準射撃が可能なものであり、ベースには九七式五糎七戦車砲用の照準眼鏡を用い、焦点鏡目盛を交換した。これは3,000mまで照準できる縦目盛と、左右各100milの方向目盛が刻まれたものである。また、間接射撃用として車長が使う照準眼鏡があり、これは三八式十五糎榴弾砲の既存装備品であった。方向射界（旋回角）は左右3度、高低射界（仰俯角）は-10度～+20度、後座長は590mmであった。砲弾は戦闘室および機関室上部の砲弾箱にそれぞれ搭載された。搭載弾数は車内16発と後部車体上の弾薬箱に12発の計28発である

[@chaseman113]

Neat, a driven mechanical fuel injection pump. The adverse of the era being Unit Injection like a Sherman's Detroit where each injector is it's own mini injection pump ran directly off the cam, this thing is more akin to a early 5.9 cummins in a eighties dodge pick up in fuel delivery with a high pressure lines to each injector ran off a injection pump.

[@dryroasted5599]

Amazingly good animation of the movement of the bogies at 11:15.

[@datatrolls]

Perhaps the direct-fire capability makes more sense if you look at this as a coastal defense weapon? I would imagine that this thing would do a number on most landing craft.

[@justforever96]

This has no resemblance to coastal artillery, they had zero expectation of being invaded when they introduced this. It is an offensive wing support weapon. They had one if the most powerful navys in the world, and were an island. They never even posted these in the home Islands, and would have no reason to. When they were introduced they were in the offensive in China and then the Pacific, who is going to be invading them? That said, it would be a terrible coastal defense weapon. It's far, far too short ranged, most coastal guns are long ranged heavy guns, this is a field howitzer, and it would be plastered by the invaders fire support. Also, what are you going to do, station them on the beaches along your entire coastline? It would take thousands of them, and what is the point is being mobile then? You might a well just emplace guns in protected bunkers...just like they did. For one of these pop guns to be effective it will have to be right on the beach hitting the landing ships as they run in the last mile or two. The only reason to have them on tracks is so they are mobile....so what, they can post them miles fromn the beach and they can all show up after the landing is well under way? How are they going to identify where it is going to take places and then drive all their mobile tracked coastal guns to that place before the landing can start, just in time to shoot them all as they run in to the beaches, while massive fire support rains in on them? There is a reason German tanks couldn't live within ten miles of the Normandy beachhead, and they put their coastal guns into reinforced concrete bunkers ten feet thick. You could use them for a counter attack against a beachhead, if you ignore the fire support, but as coastal artillery? No, that is clearly not what they were used for.

[@nicofolkersma2535]

There is a beautiful type 97 in the war museum in Tokyo.Great video, very clear.

[@D_U_N_E]

It's odd, no one seems to have mentioned that the HO-RO does not have a Chieftain's hatch, in fact, it came out way before the Chieftain, so it would be extraordinary for it to feature a hatch from one.

[@panzersusmander3728]

I might be missing the joke, but it’s called that because his nickname is “The Chieftan”

[@D_U_N_E]

@@panzersusmander3728 Missing the joke - though given the time to likes ratio, it was either bad, or more people got it confused.

[@panzersusmander3728]

@@D_U_N_E to me it was too sincere/specific to sound like a joke lol

[@D_U_N_E]

Thanks for the reasoning. I made it more specific in effort to make the joke more apparent - good to know it has the opposite effect. @@panzersusmander3728

[@robertillston2350]

Considering by 1944 Japan was fighting a defensive war, I can see these being used in fixed positions, where the mobility was just needed to move from one prepared position to the next, if the were part of the Navy's island defense. If they were in China, no clue.

[@ernestcline2868]

In 1944, Japan engaged in a massive offensive in China, Operation Ichi-Go.

[@comentedonakeyboard]

Bunker busting?

[@robertdickson9319]

In China, little to fear from AT weapons...these could just roll up and blast away

[@obsidianjane4413]

@@comentedonakeyboard Yeah that was what they were for.

[@richardstephens5570]

Not many were built, they were all used in the Philippines and Okinawa.

[@bellakaldera3305]

I've been to the AHM and seen this! My group donated an Arisaka to the collection...which is awesome!

[@tylerlawrence1997]

Always love the idea of spgs. Take a tank we already have, remove turret and/or hull and slap on the largest gun possible without wrecking the suspension.

[@Sam_on_the_tools]

just a thought on the track tension system . I would expect it uses a worm gear system, and thus you only need to stop it turning via vibration so that small latch would be enough and the smaler size of the square drive would also lean towards it using a worm drive as less torque would need to be applied by the chap and his spanner.

[@firefox5926]

26:14 honestly the whole thing reeks of a pillbox buster lol

[@ravenouself4181]

Ah, Yes, the Japanese Derp gun. Edit: "We can't get the hatches open" WD-40: You dare challenge me, Mortal?

[@rkadi6540]

Or WD-40 equivalent at that time, but i doubt they equiped the crew with it

[@obsidianjane4413]

@@rkadi6540 When new, just plain ol' oil was fine. But decades of leaving out in the weather...

[@rkadi6540]

@@obsidianjane4413 tropical weather for the cherry on top, and mosquitos attack for extra flavor of crew torture

[@TexasSpectre]

I kind of wonder if this was more built as an ad-hoc tank destroyer with what large caliber guns they had lying about in storage than as a real assault gun. In 44, as someone else points out, they were starting to encounter Shermans and discovering that their 47mm and 57mm main tank guns were not reliable Sherman stoppers. This may have been their quick and dirty solution to pump out more TDs using stuff they already had.

[@omegalpha28]

Yes as a master diesel mechanic, those mini engines are injectors pumps. They meter and injector the fuel into the engine, very much like the pump on a 5.9 cummins.

[@Tacticalsnails]

No one here plays wot anymore we just love the chieftain and these vids

[@FrontSideBus]

"There isn't enough elevation for indirect fire" In my mind, I then heard an English voice say; "But that's how they did it..." xD

[@zman1508]

Would it be worth you getting one of those inspection cameras with the light?

[@ThommyofThenn]

Depends on if you're going to be filming stuff with a lot of shadows are dark areas.

[@MakeMeThinkAgain]

To be fair to the Japanese, the BEF could certainly have used some of these at Arras in 1940. So even without an indirect fire capability they could have been useful in the right situation.

[@VolksDragon]

Woohoo, I'll check this out next week! I live near this museum!

[@TheWalterKurtz]

Well. Atleast there were never columns of them rolling down the streets of Los Angeles, San Francisco, Portland, or Seattle.

[@markwilliams2620]

For Marine logistics references, how many cases of beer could it hold?

[@Survivor00]

Hey, I was at that exact museum about 2-3 weeks ago! I saw that exact Ho-Ro.

[@paoloviti6156]

Very interesting video on this Japanese self-propelled RO-HO but perhaps putting some oil and grease here & there would have helped a bit 😂

[@fortusvictus8297]

Think what the industrial capacity and material it took to make the Yamato, Mushashi, and Shinano and invested that into aircraft or armored units. Thankfully they didn't, but it wasn't beyond their capability.

[@ScottKenny1978]

They sorta recognized that they needed a Navy a lot more than an Army. Didn't quite pay attention to the British lessons of WW1, though.

[@Allan_aka_RocKITEman]

Great video, Nick.

[@firefox5926]

6:36 man that rising sun on the side of it has gone full super nova hasn't it lol

Very interesting and nice format

[@rokoala2636]

It looks like the tensioner locking lever would depress when the tensioning tool was in place, neat setup.

[@blackstealth8168]

Would love to have this tank in the game as a TD. Even as a SPG would be nice. Just because there is not enough tanks to make a tech tree line doesn't mean it shouldn't be added.

[@DavidCowie2022]

"There's an Irish expression, it's been through the wars." That's also a Scottish and English expression.

[@pacificostudios]

Nick, you pronounced "Ho-Ro" perfectly, except for not rolling the "R." Many people get the vowel wrong.

[@jonathanbaron-crangle5093]

1:51 "We had this habit of blowing up" PMSL

[@johan-erikjohannesson2796]

From what I understand, there is a cargo ship sunk by a US submarine, that carried armoured vehicles on its way to the Philippines among which the Type 4 Ho-Ro was present. Too bad they won't consider financing recovering some of those vehicles, although I wonder in what condition they would be after nearly 80 years down on the bottom!

[@theginger7148]

It could very well be a direct-fire weapon, or maybe part of the logistics train for the vehicle included a team to aim the gun with their own tools. It certainly wouldn’t be the most efficient use of an SPG, but I’m trying to think of why a vehicle in this role would have no capability for indirect fire

[@majungasaurusaaaa]

The gun was similar to the german heavy infantry support gun. It's ok in both indirect and direct fire roles. But with scarce radios coordinating indirect fire was difficult.

[@WildBillCox13]

The Japanese did have perfectly serviceable direct fire weapons in tanks . . . but those were 47mm* cannon until late in the war. The 15cm Ho Ro had quite the better HE performance. "Pink! Pink! WHAM!" [French Accent] "Of zee feefty seven we shall nevair speak again."

[@firefox5926]

25:44 i mean so long as it delivers the high explosive to where you want it... or close enough is anything really obsolete same goes for bullets too i guess after all the mechanical contrivances may have got stronger and tougher and lighter over the years but humans are pretty much as squishy now as they were 1000 years ago

[@steveclarke6257]

Its a system like the PzI with the SiG33, a way of making mobile a big cannon to support frontline units

[@Ghostmaxi1337]

Considdering its based on German design like the Grille, s.I.G auf Pzsfl II or StuIG 33b and the gun is a license build 15 cm Krupp 05, it is very much similar.

[@stanislavczebinski994]

Hey Chieftain, a "Grill" here in Germany is used for BBQ. German end-"e" is not silent. If you would incorporate that you would basically be the only gun/weapon expert here to say it the right way. Greetings from Germany!!

[@SnakebitSTI]

Word final ⟨e⟩ in German is usually /Ə/?

[@firefox5926]

5:56 which is ironic where you think about where the base material for rubber comes from lol

[@herosstratos]

The behavior of the undamped suspension of the running gear when driving off-road may have been interesting, but it will probably have been even more interesting after firing the gun.

[@Kwodlibet]

Ho-Ro Chieftain! It's good to see you too 🙂

[@pacificostudios]

The U.S. Army museum in Waikiki at Battery Randolph has a Type 97 Medium tank. I don't know if it's the most intact in existence, but you can start with them. :-)

[@richarddouglas688]

That tank is a type 95 ha-go.

[@pacificostudios]

@@richarddouglas688 I thought there were two IJA tanks there. Of course they are stored outside and might be in worse condition, but the staff may have more information in their files.

[@richarddouglas688]

@@pacificostudios The other tank there is an M24 Chaffee. I was just there about 2 weeks ago. The type 95 is somewhat worse for wear, especially when compared to the M24, which is also not in very good shape.

[@jaymorrison2419]

Up at Collings I see! American heritage is a great collection.

[@michaelmcdonald3195]

Love all the videos.Learn lots about ww2 armor.

[@ulissedazante5748]

"why there are six levers and only four directions?"

[@TheChieftainsHatch]

I was thinking Red v Blue myself at the time...