MangaNOID

[WIP] Datsun 240Z .... body work slow

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I can live with bump steer. Its not like it will ever matter at it is a Sportscar with 1 Stud suspention travel, and very hard suspension, so It will never happen when I play with it (manual model). As I said I dont have a coice anyways, a dual shock setup is nececary. I myself prefer a strong, functional suspension setup over a weak one with perfect geometry. I overbuild my suspention, because I hate the thought of bending/breaking stuff. That comes at a price, so I had to make some compromises.

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Building strong and accurate are not mutually exclusive. And i get no satisfaction from a model if i don't get the suspension right.

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5 minutes ago, nicjasno said:

Building strong and accurate are not mutually exclusive. And i get no satisfaction from a model if i don't get the suspension right.

You are right, but it does require more space to build strong AND accurate. Space I dont have :sceptic: so compromises had to be made :oh:

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3 hours ago, Gray Gear said:

You are right, but it does require more space to build strong AND accurate. Space I dont have :sceptic: so compromises had to be made :oh:

I disagree. That datsun suspension is a perfect example.

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4 minutes ago, nicjasno said:

I disagree. That datsun suspension is a perfect example.

I dont want to insult anybodys work here, as I am far from perfect myself, but excuse me, that suspension setup is neither particularly compact, nor is it overbuilt, I myself would not trust this setup with a <2.5 kg model.

You seem to know a lot more about suspensionthan me, so you might be able to surprise me:

I need a twin shock setup with double wishbones on the front wheels, the wheel has to be mounted between two studs. The suspension is not allowed to be taller that the wheel itself, and is only allowed to go 4 studs to the inside behind the wheel. The setup has to be able to hold 1kg without any compression  of the shocks or flex in the setup. The space between the suspension has to be free, but a cross bar is allowed. Groud clearance of the vehicle has to ~2 studs. The bottom of the vehicle has to be 2 studs thick only, including the steering.

 

I doubt you can achieve that with perfect steering geometry.

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2 minutes ago, Gray Gear said:

I dont want to insult anybodys work here, as I am far from perfect myself, but excuse me, that suspension setup is neither particularly compact, nor is it overbuilt, I myself would not trust this setup with a <2.5 kg model.

You seem to know a lot more about suspensionthan me, so you might be able to surprise me:

I need a twin shock setup with double wishbones on the front wheels, the wheel has to be mounted between two studs. The suspension is not allowed to be taller that the wheel itself, and is only allowed to go 4 studs to the inside behind the wheel. The setup has to be able to hold 1kg without any compression  of the shocks or flex in the setup. The space between the suspension has to be free, but a cross bar is allowed. Groud clearance of the vehicle has to ~2 studs. The bottom of the vehicle has to be 2 studs thick only, including the steering.

 

I doubt you can achieve that with perfect steering geometry.

Everything can be achieved with perfect steering geometry. It's just how much thought you are willing to put into it. Myself, if i have to do a double wishbone setup i prefer to position the steering links on the oposite side of the springs. Like here for example:

KVz0zWi.jpg

The datsun suspension here basciaclly just needs the yellow shock absorbers and it's good for the intended model.

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I dont get it - saying everything is possible with perfect steering geometry, if you just put enough time and effort into it is easy. But let me tell you, there is a limit you will hit, that limit depends on the way the vehicle is built. Believe me, I put in multiple weekends just developing and improving on this setup. 

 

Also, how am I supposed to place the link on the opposite side of the spring, if there are springs on both sides? I did mention i need a double shock setup per wheel, right? And it has to be symetrical, so all the load is distributed evenly.

 

Maybe I'll do a help Thread for this, so someone experienced can show me how it is done. Then one of the admins could move this entire conversation out of this comment section.

 

Like i said, I do not think the Supension setup for the 240 is bad, It will probably do fine If he keeps an eye on the weight. Its just me that would not be willing to put it to such a heavy task.

Edited by Gray Gear
I accidentally removed a "not" there while editing my grammar- being on mobile is bad...

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1 hour ago, nicjasno said:

Everything can be achieved with perfect steering geometry. It's just how much thought you are willing to put into it. Myself, if i have to do a double wishbone setup i prefer to position the steering links on the oposite side of the springs. Like here for example:

KVz0zWi.jpg

The datsun suspension here basciaclly just needs the yellow shock absorbers and it's good for the intended model.

I see you changeded the length of your steering links. I've considered doing that but never have.

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16 minutes ago, 1963maniac said:

I see you changeded the length of your steering links

I noticed that as well...I dont think cutting up pieces counts as "achieved by putting thought into it" in the LEGO world :laugh_hard:

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On 9/22/2019 at 6:00 PM, Gray Gear said:

I dont get it - saying everything is possible with perfect steering geometry, if you just put enough time and effort into it is easy. But let me tell you, there is a limit you will hit, that limit depends on the way the vehicle is built.

I suggest we make a new thread for this, to not pollute the OPs build thread with this discussion. I'd like to see the chassis you are talking about.

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I had a painfull time with this steering.

its a little loose feeling still and I think that is down to A: the steering links on the balls and B: using the small turntable at the top which has a very loose fit like a non friction pin. You know, sometimes you can tighten up steering by using friction pins but not with the turntable (?)

so I have gone through as much as possible elsewhere in the steering to tighten up as much as possible. Even though this is intended (maybe as a consequence of the previous) as a shelf model (maybe on a technic plinth :grin:) and the steering would no way hold up on an motorised version.

This was my strut assembly

2172eca1-fb8c-4c87-83b2-6155f1918de3.jpe

things wrong with this were the wheel was only supported by one stud hole and the axles holding the turntable to the liftarms are not as tight as pins. so I changed to pins with bars in them (due to half stud stupidness) and added further support for the axle itself rearward of the hub.

19811154-a277-422a-9f0f-bbc4d3803dad.jpe 0006f15b-022e-485a-a752-f275a6216fde.jpe df0be5ce-6122-406e-882e-45430ef5dfa2.jpe 6b88c30f-95f6-4abd-87f2-c0cfa0484e93.jpe 

eb3f1178-5950-49db-94e4-968f55eff9cb.jpe 

 

 

I tried to keep the steering ball as close to the swivel point as possible to be able to use the small wheels and have them in close to the hub as possible too. This is a compromise,as most things are, as the steering point on the hub further out would reduce steering looseness if i'm not mistaken. Also this keeps the steering rack and links in line and the rack close to the crossmember like the actual car and the steering input offset to the proper side of the car...that is because its the rally version of course :blush:

using the 2L bar with ball for the steering link allows me to put the steering link 'too far' over the ball which tightens things up a little bit more.

the steering rack closely resembles the 240z setup as best I can in Lego without too much excessive Lego-ness. Well that's my opinion anyway :grin:

what I am interested in is with this build is  keeping the look of the Datsun as close to possible as the original car which means compromising rigidity I suppose, as I found out with the steering. I work hard on this though to get maximum rigidity with minimum liftarm frames that would spoil the look in my opinion.

And the engine bay is looking open like the 240z as best I can.

a6c31924-c623-4c22-8288-b2e6781fd35d.jpe b6afe071-5460-4612-8c9b-0721c982a85b.jpe 

 

240z_steering.png 

 

A few details I may incorporate is (fake) disc brakes (these match the diameter of datsun brakes almost perfectly in 1/8 scale!) and some hose maybe to look like brake hose which is a bit off in scale with pneumatic hose so we shall see.

firewall is going in next to see how the engine bay holds up in strength. I am worried at this stage that the strut towers will still push inwards when compressing the suspension.

otherwise the real build is looking and feeling OK (using available colours that I have at this stage of course)

fa40a70c-4376-4210-a2f7-e9ea52445cd4.jpe 

 

EDIT: I also tried to add tie rods to stiffen the suspension arms and that helps a little also. 

33e112ed-9cea-489d-af90-ef99f38cd824.jpe 

 

 

 

 

Edited by MangaNOID

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This is not easy with the body work. 

Its slow going, I think the shape is getting there without too much parts usage. some parts are 'floating' in this pic so I can see where they need to be to then connect them. not sure if there is a better way but this seems to work for me.

Chassis is going ok and I am more confident in my building for that.

More respect for the difficulty in scale technic building :wacko:

240z_chassis_moc.jpg 

 

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This is shaping up to quite an interesting challenge. Using that many system parts at this scale will be a challenge for the suspension though. My advice would be to try to do as much as possible with Technic panels (and flexaxles). They are much lighter than brickbuild surfaces and curves.

BTW I love that front suspension, I hope it is stiff enough, both in structure and in spring.

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18 hours ago, LegoTT said:

I didn't understood the half stud thing...

It just that I put the suspension and cross-member half a stud off from the rest of the car making things a bit more difficult for myself trying to chase good scale when that was probably a bit to pedantic for my skill level. you can see it in this photo best with a half stuff either side of the suspension towers.

df0be5ce-6122-406e-882e-45430ef5dfa2.jpe 

 

18 hours ago, Jeroen Ottens said:

Using that many system parts at this scale will be a challenge for the suspension though.

I hear you indeed, thanks for the reminder. I was supposed to just be using flex axles for the body with a few panels here and there but I'm going too overboard maybe.

I knew this body work would be hard for me but this is just crazy difficult :wacko: I'm starting to study a lot of MOC's by you lot of cars to see how people connect stuff and do this.

little bit of chassis, little bit of body, little bit of functions just trying to line everything up as I go thinking of everything else at the same time. As I said more respect to scale model builders!

A bit more floating body work to make sure it looks like a 240z as that other photo above looked more like a Mazda MX-5.

 I need to build some more physical chassis now to catch up but the shape/scale is kinda lining up

datsun_240z_b.jpg 

Edited by MangaNOID
forgot to add photo for half stud explaining

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fake gearbox.

I spent the last couple weeks trying to build a gearbox but didn't want an overbearing (in size) box that didn't sit in the right place in the car and didn't operate somewhat like a real 4 speed box so I built a fake gearbox that kind of simulates a real 4 speed box with reverse. Fake meaning that when a gear changes, no ratio changes are made to the output, i.e. same ratio output in every gear.

but in doing this I am able to have a H pattern shifter simulated in the (almost) correct spot in the car (out by 1 stud) it works really well and glad I can have that simulated in the model rather than gear ratio changes which is perhaps not so playable in a manual model.

365de4af-5a37-458f-a003-3534b228b971.jpe 

 

c155301e-e83f-449e-b7ba-4db88e336428.jpe 

 

Below is a better way to see it. 

The gear stick is held in place by the ball that squishes between liftarms. 

1st and 2nd gear is the yellow. 3rd and 4th is purple and green is reverse.

All gear function will be in the correct 'H' pattern for each 'gear' like in the real 240z because of the way the shifter gear lever pivots from where the ball is.

Once in a gear the shifter is unable to accidentally slide into another gear.

Very happy with this design and compromise over a 'real' LEGO gearbox

240z_chassis_gearbox1_copy.jpg 

240z_chassis_gearbox2_copy.jpg 

 

I also want to keep this as visible as possible (its Technic right) so hopefully, depending on structural integrity, this will somewhat be visible through the transmission tunnel through the window of the model to see how the gears change.

240z_chassis_gearbox4_copy.jpg 

 

also managed to secure the engine in place on a lean like the real engine. 

240z_chassis_gearbox3_copy.jpg 

82d552e7-a969-40bc-86b2-abecbad2a7ed.jpe 

and managed some 70's style vinyl looking (?) seats.

240z_chassis_gearbox.jpg 

 

 

 

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As a Gearbox guy I feel personally offended by this :tongue:

I made this compact 4-speed transmission prototype for you, took me like 15 minutes. Please consider using it. It shoud work with a similar shift system.

IMG_20191017_192956.jpg

IMG_20191017_193017.jpg

IMG_20191017_193052.jpg

The tan Gears are supposed to be the blue ones from the Bugatti, I just dont have any left. You might have to switch up some stuff, depending on what axle is your Input and which is your ourput.

 

Edited by Gray Gear

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Mmm, that’s quite clever! I am not a gearbox guy :wall:

Its obviously little different from a real gearbox but about as close as could be?

It is 3 studs longer of course using the newer gear changers. I’m not sure I have the capacity to re build this into the model. Trying to keep the gear lever in the same spot. And not over load the look of the model.

I mean really it took me more time to work out how your gearbox worked than you took to make it! And it took me 2 weeks to make a gearbox that doesn’t change gear :blush:

I’ll play around with it though for sure, thank you!  :thumbup:

Otherwise its just something else to add to the list of un-used help from others :blush: :sad:

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Ooh I can see your problem...your shift lever ist behind the transmission...that makes length a bigger issue. All transmissions I designed so far had the shifter in front of the transmission.

At least there is no need for a Shiftlock System in a simple 4speed. But with your reverse gear, there is indeed a need for such a system. How will you prevent the reverse gear from accidentaly engaging when shifting in the center column?

Also, these half stud reverse gears willl disengage themselves as soon as they are supposed to spin.

 

I am sorry to do this, but I have done my fair share of digital gearbox designing, that ended up not working irl :laugh_hard:

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1 hour ago, Gray Gear said:

How will you prevent the reverse gear from accidentaly engaging when shifting in the center column?

Also, these half stud reverse gears willl disengage themselves as soon as they are supposed to spin.

Yep well spotted. So the half stud gears for reverse do indeed ‘slop’ about at the moment, but I will try and hide another of those clutch sliders to the reverse axle and that should lock it in neutral or engaged position. The rest of the ‘gearbox’ works really well so far.

 

1 hour ago, Gray Gear said:

Ooh I can see your problem...your shift lever ist behind the transmission...that makes length a bigger issue. All transmissions I designed so far had the shifter in front of the transmission.

And yes gearbox squished in front of shifter (which is almost as big as the gearbox itself) maybe I could move the gearstick back 3 studs to accommodate your gearbox but that would look visually strange for having the shifter so close to the seats, still deciding though, it’s a close call on what I want from this model.

 so compromises/choices unfortunately. We got to make them I guess and I suppose a ‘working’ gear box might not be that important to me if I have to choose. I know that’s almost heresy to a lot of you as gearboxes seem quite popular here  :grin:

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Do you have some old gear shifters and Bugatti gears at hand? If they are compatible (I never tried that) you could modify my design to use the old shifter rings. That way it would only be 1 stud longer.

Edit: Just tried it, does not work :sceptic:

Edited by Gray Gear

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Fake 4sp+R  gearbox finished.

Not entirely happy with the fake gearbox but other than ratios it does replicate the original Datsun one.....somewhat....and its size is pretty good and thin so the transmission tunnel doesn't overbear the interior and the shifter works somewhat like the real. and its loose when in gear which is just like a Datsun :iamded_lol:

reverse is now held in place with a ring gear changer.

ummm...what do you think :sceptic:

 

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