Logic Defying V5 Engine - Honda's RC211V Explained Like Never Before
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Published 2022-07-24
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Official patent: patents.google.com/patent/US6745730B2/en
RC211V model: amzn.to/3PSE9Yv
In 2002 Honda introduced the RC211V motorcycle to MotoGP, the highest level of motorcycle racing in the world. The bike was a response to the chaning rules of Moto GP and replaced Honda's previous contender, the iconic two stroke NSR500.
Now the big deal about the new bike is that it's engine was something that no one had ever seen before, a V5. I mean over the decades we have been conditioned into thinking that a V engine must have an even number of cylinders, V2, V4, V6, V8, V10, V12. And Logically it makas sense....we have two banks of cylinders and both banks have the same number of cylinders which means that neither bank is generating more force than the other bank leading to a well balanced engine.
The general public was so puzzled by the V5 engine, which has 3 cylinders in one bank and 2 cylinders in the other that soon rumors spread claiming that the bank with two cylinders had larger bores and larger pistons to restore balance. This of course wasn't the case, all pistons and bores are of the same size. But even to this day, many people believe that a V5 engine is impossible and would self-destruct in operation. However Honda proved this wasn't the case, not only did the engine NOT self-destruct, it revved continuously and reliably to 14.000 rpm, and it did it it's job so well that it helped Honda win three rider and four constructor world championships. In fact the bike won 48 out of 82 races, it won more than half of all the races it entered, which is an extremely impressive statistic for MotoGP and even more impressive for an engine that should self-destruct according to layman logic.
How do you make a V5 work? Well the answer is pretty simple....you make it work by building an unbalanced V4 and then using the extra piston to balance things out.
So how do you unbalance a V4? Well that's easy, you loose the 90 degree angle between the banks that allows the counterweights to keep things balanced. This why Honda gave their V5 an angle of 75.5 degrees between the two banks. The added bonus of this is that it makes the engine even more compact and allows the wheelbase of the motorcycle to be shorter which improves handling response.
But why exactly 75.5 degrees? Why not 80 or 70 or whatever else. Well the answer to that is that 75.5 is the point at which the piston of an internal combustion engine is at or near it's maximum velocity.
And why is this important? Well to understand that we have to observe the V5 engine in action. As you can see Honda's V5 is essentially a V4 with zero degrees offset between the two common crank pins, and an unpaired piston on a single crank pin between the two piston pairs. As we know the angle between the two banks is 75.5 degrees and the crank pin of the unpaired piston is offset by 104.5 degrees from the center-line of bank 1 when the engine is in this position. These angles result in the forces created by the engine canceling each other out. See video for actual detailed explanation with graphics.
One more final side-point just in case someone is wondering. No, the engine called V5 by Volkswagen does not work like the one we just discussed. As far as I know the V5 in Honda's RC211V is the only one of it's kind and it was never mass produced, it was made only to compete in Moto GP. What Volkswagen calls V5 isn't really a V5, a much more appropriate name for it would be VR5, in the same fashion as their VR6 engine. Honda's V5 is a true V engine with two cylinder heads and two sets of camshafts, cam gears, etc. Volkswagen V5 is just like a VR6 but with one cylinder less, meaning that we have only I believe only 15 degrees between the banks, one cylinder head, one set of cams etc. And just like the VR6 has balance very similar to an inline 6, so too does VW's „V5“ have very similar balance to an inline 5
A special thank you to my patrons:
Daniel
Daniel Morgan
Pepe
Brian Alvarez
Jack H
Dave Westwood
Joe C
Zwoa Meda Beda
Toma Marini
Nelson
00:00 MotoGP champion
02:43 The role of the counterweight
04:37 The magic of a 90 degree V
07:00 Velocity and acceleration
10:42 Balancing using imbalances
15:20 Volkswagen "V5"
#d4a #v5 #enginebalance
All Comments (21)
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Patreon: www.patreon.com/d4a Support d4a: driving-4-answers-shop.fourthwall.com/ Official patent: patents.google.com/patent/US6745730B2/en RC211V model: amzn.to/3PSE9Yv
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Yet another tremendous explanation of engine science.
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This was the engine that unintentionally cemented Rossi's legacy. Rossi left for Yamaha to prove that it wasn't just the bike... but the RC211V was just a stellar bike in that sweet spot right after 2-strokes ended.
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My brain hurts...but I fucking love this...I haven't seen any other videos that goes this deep in detail about one of the most iconic engines ever made...Thank U D4A <3
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Honda and Suzuki built V3 engines before, Suzuki didn’t use theirs because of a rule change but Honda used V3 engine in the NS400r roads bike and the NS500 before the V4. Good video, you do an excellent job of explaining complicated principles
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Not only did I learn how this V5 even functions, but also the other even V-type engines. Awesome video
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The brain pain term is perfect for describing this engine. I scratched my head many times to find out how does it actually work 😅
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I respect how much work you put into these videos! Well done and very clearly explained!
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Nice job on explaining a very complex engine. I'm an old motor mechanic, I'd heard of the glossed over fact that the Honda V5 used the extra cylinder to balance the other cylinders, but hearing the engineering behind it certainly makes your head spin 🙂👍
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When MotoGP switched from two to four stroke engines, minimum weights were based on number of cylinders. Twins, triples, fours, and six cylinders all had different minimums. I read somewhere that Honda wanted to use a V6, but it would have to be too heavy.
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This is a variation of the trick Honda did with their 52 degree vee twin engines. The crankpins are offset 76 degrees. (76/2)+52= 90 degrees. They have a 232 degree firing order but emulate the balance of a 90 degree vee.
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4:03 This is the golden rule for engine balancing, primary forces and couples are (always, in theory) "averaged out" so that they are "circular" (equal in magnitude in the horizontal and vertical directions).
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This just tells me we need more odd cylinder engines. Such a clever squeak of efficiency.
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It's videos like these that show you really know your stuff. Incredible work. Thank you for bringing knowledge to us!
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Your surface level coverage of V-engines BLEW MY MIND. Now I understand why people say "V engines are smooth".
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I like Donut Media and other channels for making things more accessible, but I'm often left with more questions than answers. On the other hand, channels like this make me really know why it has to work the way it does, and makes me respect these pieces of engineering for what they actually have to put up with to not only be put on the market, but succeed at its daily tasks and the demands made of it. And then there are the people who wonder why self-driving cars aren't here yet.
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I think you should have been an engineer, hahaha. Designing the world's first cross 7 engine. Just do it. It's awesome how having watched most of your videos leading up to this, I either already understand principles you're going to discuss or know what you're going to talk about before you get to the next subject. You really help people understand all these concepts and that's so amazing. Mad props. On to 1M subs!
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That was one of the most informative and interesting mechanical things I've ever learned, and that's for over 56 years! Very very cool my friend, thank you!
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I understand the idea that you have to create an unbalance V4 engine first, but the thing is you obviously have to do so with a v5 in mind (meaning that you have to determine exactly the perfect imbalance of v4 engine you want before you can make it a v5). It really does seem like genius engineering, exactly why I am studying to be a part of this field
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A great use of fusion 360... The animations were nicely done and helped to understand the complexity of the design
