This is The Strongest Transmission Ever Built - Planetary Manual Lenco Gearbox Explained

Try Onshape, the world's most capable in-browser CAD software for free for 6 months: https://Onshape.pro/d4a Planetary Gearset I used: https://cad.onshape.com/documents/f0457e500ee8181604a67dad/w/19556b2afaed74c80139aa9e/e/539e345309585e8be2ebd8d3 Onshape Learning Center: https://learn.onshape.com/ Big discounts on Bambu Lab printers, filaments and accessories: https://tidd.ly/48q4vgM Support the channel by shopping through this link: https://amzn.to/4fatbMb Become a member: https://www.youtube.com/@d4a/join Patreon: https://www.patreon.com/d4a If the algorithm thinks you’re into cars it has probably shown you a video of a planetary manual transmission, aka a Lenco transmission at some point. And many of you have probably wondered what the heck was it that you just saw? But have no fear d4a is here! And today I’m explain what kind of transmission a planetary lenco is and why it exists. I will also explain exactly how planetary gear sets work with a special little model that I made and finally, I will explain why Lenco planetary transmissions are the strongest transmissions ever made. Transmissions of this kind first started appearing back in the late 60s, early 70s in the USA when engines started to make serious horsepower and torque. Ever more displacement, ever more aggressive camshafts, ever larger superchargers all lead to the fact that race engines of the time started to eat transmissions like cookies. The hydramatics, powerglides and muncies of the time simply couldn’t keep up. That’s when Leonard Abbot started Lenco, a company manufacturing planetary transmissions for racers. He gave racers everything they wanted. An unbreakable transmission that could shift faster than any manual or automatic and without lifting the throttle or pressing the clutch. Inside a Lenco transmission you will find this. A planetary gear set. Planetary gear sets consist of three types of gears. The outer ring gear. The inner sun gear. And the planet gears which revolve around the sun gear. Each of the gear types is attached to its own shaft. An actual Lenco is composed of multiple modules. Each of the modules consists of identical parts and inside each of the modules you will find a planetary gear set. The only difference is that every gear set has it’s own gear ratio. You get first gear by multiplying the ratios of all the modules together. You pull a lever and you lock the first module. That module is now 1:1. Your gear ratio is now the result of the multiplication of the remaining modules. You keep pulling levers and locking gears until you get your final gear ratio of 1:1. If you have four modules then you have 5 speeds. If you have 5 modules then you have six speeds and so on. Okay, so why is it so strong? Because a lenco combines the mechanical advantages of a manual with the high number of gear contact points of an automatic. Let’s think about launching in first gear. This is the moment when you dump the clutch and shock the transmission with a sudden release of thousands of Nm of torque. In a manual transmission in first gear all of our torque is transferred through only two contact points. A single planetary gear set has 6 contact points. If you have a 5 speed Lenco you have 24 contact points. You are not breaking that many gears. Now in a automatic we also have planetary gear-sets. The engagement of their parts is controlled with clutch packs just like in a Lenco but the clutch packs are controlled by fluctuating hydraulic pressure. On top of this the clutch packs need to slip slightly during engagement to create a smooth shift. In a Lenco the clutch pack engagement is instant and they are clamped down by mechanical force. This ensures a bulletproof engagement and clutch holding. The other reason behind Lenco’s strength is that all the gears are straight cut as opposed to helical gears found in OEM transmissions. No, straight cut gears are not stronger than helical gears. The problem with helical gears is when you spin them they rotate but the direction of their teeth also creates an axial force. In other words the gear is trying to move along it’s shaft. To absorb these forces helical gears and shafts needs thrust bearings and strong transmission cases. This is why racing transmissions use straight cut gears. They are noisy, just like the straight cut reverse gear in your daily driver but they create zero axial loads which means that you don’t need thrust bearings and you don’t need to worry about tearing your casing apart with your monster engine. The drawbacks? Lenco transmissions are long, noisy and they suck at downshifts but none of these are relevant because this is primarily a drag racing transmission designed to reliably transfer maximum torque and horsepower over the length of a dragstrip and it does that very very well. A special thank you to my patrons: Daniel Zwoa Meda Beda valqk Toma Marini Cole Philips Allan Mackay RePeteAndMe Sam Lutfi Cakeskull #d4a #planetarygearset