[TC18] Mini Porsche 959 AWD

[jorgeopesi]

I share all my thoughts here TC18 and how I am learning what I want in this scale. I tried suspensions but they are fragile and we need too much pieces and space, I tried without differentials with AWD car and pushing it I noticed that is better with differentials and I tried simple steering without ackerman and it works much better being ackerman. We all are learning and I need a simple car that can be pushed and steered very well being strong and we will see if a little nice with 3 or 4 details, engine, doors, whatever. We all follow a different way and none is bad and all teach something.

[sirslayer]

@jorgeopesi.  Thank you..  "Push" is different then RC!!!   I actually need to push more often.. and its an AWD with center and a locked diff is no different then my setup..     its called positraction.!!   but I do plan for the model to be enjoyable .. Building new chassis.. 

[1gor]

Gentleman there is a simple (and reasonable) reason for differential - when turning inner wheels have smaller radius which means Thea are traveling shorter distance than outer, so differential compensates this; the same is when you build all wheel drive vehicle with e.g. smaller front tires like classic tractors, or smaller rear tires like combine harvesters... So @sirslayer (IMHO) if you can use differential instead of gearbox, that would be better compromise.

Kind regards my friends

[sirslayer]

I heard and listen fellow fans!!  

Version 3.0 Rear chassis!!!   The best just gets better...   I was able to integrate the new differential  to the latest build and still got my independent suspension (swing axle) and wide tire compliant but just in case ill submit the corvette tires for the contest ...   2 speed Hi/Low transmission matted to a twin turbo flat 6 with real pistons,fan and valve rockers on the head just like a real petrol  engine!!!  Center diff that distributes 50/50 power to the rear and front new 5 geared differential  ..   more to come ..  and like the real Porsche 959, this MOC has been ground breaking with so much tech per squared  inch!!!  

Lego Technic 959 rear chassis (new diff) by victormendoza_jr, on Flickr

Lego Technic 959 rear chassis (new diff) by victormendoza_jr, on Flickr

Lego Technic 959 rear chassis (new diff) by victormendoza_jr, on Flickr

 

Lego Technic 959 rear chassis (new diff) by victormendoza_jr, on Flickr

[keymaker]

@sirslayer I am sorry but have to ask. Why your photos are so dark?

[sirslayer]

@keymaker.. because its 1:40 past midnight!!!   and our eyes hurt during the daytime..             I'll start producing brighter pictures..   cause I just like the "dark theme"  

[sirslayer]

Hummmm... Now I know how the 959 AWD system operates.    The front differential, which distributes the power it receives to the wheels, has been modified in such a way as to make the classical third longitudinal differential unnecessary. The job of distributing the movement equally between the front andrear axles is in fact taken over by a brand new clutch called the "PSK", which stands for Porsche-SteuerKupplung, i.e. Porsche command clutch. It is a particularly interesting component, as its structure allows direct control of its working. It consists of 13 plates, seven outer and six inner, in an oil bath, with modifiable reciprocal slippage ...

well, i guess I need to modified my drive train and chassis . I would like to add this to  my model if possible!!  

and  if you're interested.. a copy of the real Porsche 959 owners manual!!!!  

https://drive.google.com/file/d/1385IKExVUAxTp19HZyF1tTIGaYrm-AKb/view?usp=sharing

  

 

[Go-Kart]

Your quoted description of the PSK is also in dark theme

Can't you use an CV-joint at the rear axle to move the pivot point more to the centre and to get longer swing-arms?

[1gor]

6 minutes ago, Go-Kart said:

Your quoted description of the PSK is also in dark theme

Can't you use an CV-joint at the rear axle to move the pivot point more to the centre and to get longer swing-arms?

Then wheels will fall out to keep 15 studs width, or axle 5.5 will be used, but then overall width will be over 15 studs...

[sirslayer]

@Go-Kart One of the Technic challenges is to design and build the wheel!!       where your wheel doesn't slide off the axle and/or the axle doesn't slide off the wheel.  most Lego Technic wheels have two side like a coin, heads and tails or on a wheel... positive or negative  rim offset.  On my diagram (studio 2.0) the 3 yellow color wheels the center wheel is negative and the two outer are positive .and when it comes all the math and angles, just having the wheels on either or offset , the positive side of the wheel can save you 1 or 2 studs of length and the pros and cons varies when other factors like king pin inclination , tire scrub ,ect ect .. but for now its about the axles..     on my diagram .. which you can barely see the female end of the cv joint, the cv axle joint is a friction less which cause axles of all sorts to easily slide right off.. goes against rule  two, axles can't slide out.. Axles with stops comes in very handy.  a few example are shown. On this contest , i need to use the brown colored axle with stop with the 47mm ?? corvette tires in order to be 15 wide complaint . Ideally using the parts @I_Igor recommended  provides the best anti slide designs but urges the desired length .

Lego technic the more you know , the better you"ll be off by victormendoza_jr, on Flickr

 

[Go-Kart]

Thanks for the explanation guys! I missed that the U-joint has no friction because I don't own this (yet).

[sirslayer]

 

Porsche 959 

PSK

Porsche-SteuerKupplung 

The command clutch, when I first started building my moc, I wanted to have features on my model that the real Porsche 959 posses.  The AWD was the most challenging since it was using concepts with clutches that I don't think if Lego technics can reproduce ..  The idea is that the output of the transmission can be split and be user control (4 different settings) between the front and rear axles. The center diff was replaced with clutch plates (13 total) and on my model , I have just added a 4 plate setup with 2 plates goes to the front diff and the second set of plates goes to the rear diff.. I I took one plate off from the front diff and moved it to the rear , then the output would be 25% front and 75 percent rear.  so a 50/50 split  is good since its one of the 4 PSK settings.. The only issue im having is it really necessary to add this feature  in the moc since it adds friction to the drive train when you want to push it around!!!????   i worked on this for many days... and I even manage to squeeze  a working 4 plate setup..     

well I also done a front end concept and I even took a outdoor picture a night and took a picture of the Mars, Jupiter ,Saturn and Pluto conjunction with my model in the picture!!! 

 Lego Technic Mars , Jupiter, Saturn and Pluto Conjunction special by victormendoza_jr, on Flickr

Lego Technic Mars , Jupiter, Saturn and Pluto Conjunction special by victormendoza_jr, on Flickr

and see the Red color spot on the right side above the car.. It's Mars!!!

Lego Technic Mars , Jupiter, Saturn and Pluto Conjunction special by victormendoza_jr, on Flickr

Edited April 24, 2020 by sirslayer

[sirslayer]

Here are the required upper chassis picture without body for the contest requirements and it took me all week to designed the ultimate PSK under Studio 2.0  and the outcome is that it required the Powered Up system and programming the PU motors to engage/disengaged the locks from the built in sensors  on the Powered Up.  maybe the angle tilt sensor on the Powered Up can be used to optimized the clutches when you go in fast into a curve and the body rolls is compensated via the motors/clutch and software!!!!!!   first concept of this idea needs to be done latter..  using a mini model is to small and the contest doesn't allow any electronics.. The following images is for size reference and may not be the final build.  

Note: the springs on the front axles act like a link !!! 

 

Lego Technic Porsche 959 chassis and PSK (wip) by victormendoza_jr, on Flickr

Lego Technic Porsche 959 by victormendoza_jr, on Flickr

 

Edited April 27, 2020 by sirslayer

[1gor]

I hope that you will have necessary parts in white, because if not instead of "It's Mars", there will be "Houston we have a problem (again)". Hope in few days you will finish it. 

[Seasider]

Not having followed this thread in detail but what are the 4 white clutch gears in a row for?

[sirslayer]

When is it due??????    The deadline date is Monday, the 18th of May 2020 

.   

@Seasider  The original PSK design by Porsche features 13 clutch plates that substitutes the center differential and located near the front diff for weight distribution. The clutches provides the driver to program between 4 different torque distribution settings like 50/50 front/rear torque split , 40/60, 30/70? and 20/80..  the 20/80 front/rear torque split, the whole system is "unlocked" while 50/50 is considered locked diffs..   On my model, the 2 pairs of clutches , the first pair of two is connected to the rear diff and the second pair is connected to the front diff.. im re-designing  the PSK on my model to a simple PSK after testing the dual clutches for the last few days the results were mixed but the clutches did act like a center diff .. the issue is that i needed a clutch lock so both sets of clutches are locked for a true 50/50 split.. more on that later when I introduced the simple PSK method..  thank you for that important question.. :)  

Edited April 28, 2020 by sirslayer

[sirslayer]

note: the 50/50 split is for rough weather driving while 20/80 is for high speed

[Seasider]

That’s a great way of representing the diff.

i wouldn’t use BrickLink at all myself at the moment, which did dictate my TC18 build. You just don’t know what each persons restrictions are with Covid.

[sirslayer]

Yes and thank you @Seasider and my parts came in so I hid some content..  :) 

Pi  (3.142) was used in designing the Porsche and using the same concept , I was successfully  able to re-create the classics look and a sneak preview of the body........ 

Lego Technic Porsche 959 by victormendoza_jr, on Flickr

IMG_20200428_020149126 by victormendoza_jr, on Flickr

Lego Technic Porsche 959 by victormendoza_jr, on Flickr

 

 

Edited April 28, 2020 by sirslayer

[Go-Kart]

The rear wing makes it so recognizable!

For reducing the stress on the two the 13x3 curved panel of the bonnet, I would probably use two of toggle joints to connect the lower part of the panels and two pin with pinhole for each of their upper links.

 

[sirslayer]

@Go-Kart 

Thank you and good idea on the upper links, the lower part needs a major re-design..  I forget there is a trunk up front!!! This is my first supercar moc!!   and its a mini!!!    Well , I've done again!!! the best gets better!!!   I've redone the rear suspension and Wow!!  Floating differential ain't that bad!!! My design fixes most issues other users designers couldn't resolved .. this design have less parts count , a cradle over the diff so it doesn't separate under torque and 15 wide with the Corvette tires on!!  it haves a 2 stud travel over bumps and it mimics a full independent suspension ..   in a itsy bitsy space .......  (drum roll)     ver 4.0 rear suspension !!! (applaud) 

 

 

 

Lego Technic floating differential by victormendoza_jr, on Flickr

Edited April 28, 2020 by sirslayer

[1gor]

Nice rear suspension 

[sirslayer]

Porsche_959_02pop shared by victormendoza_jr, on Flickr

Lego Technic Porsche 959 by victormendoza_jr, on Flickr

 

Just for reference , comparing the model and actual car. I know its dark!!!   

Edited April 29, 2020 by sirslayer

[sirslayer]

Thank you @I_Igor..   

here is a bit more body work..   ( non bondo) That is the bottom of the  trunk and it almost fit like a bonnet/hood 

Lego Technic most talented by victormendoza_jr, on Flickr

 

Edited April 29, 2020 by sirslayer

[1gor]

Now it looks better (without the mask)