Hakosuka GTR

Ghostpig

V.I.P. Member
Wow that's quite a bit of parts assembled!! Under chassis view looks awesome, really digging it. Were you able to test the front geometry even though you have a bit of mechanical interference to file? Toe and camber throughout steering, bump steer, caster etc, did you get it dialed-in pretty good the first time? I guess with the 3d software you were able to test some of those movements?

Thanks! I didn't really test the geometry. Only tested the suspension travel and if the lower arm hits anything. With my CAD and skills I can't do any proper test. I'll have to move every part separately. Some of the steering interference can be fixed with shorter ball ends. Currently they are too long because I didn't have long enough turnbuckles. I should get some and then see how much I'll have to file.

I like these ball ends. https://fi.eurorc.com/product/9349/xray-ball-joint-49mm---open-4
Bit expensive but they are nice and small and they will help with the steering interference.

It is cool that you found F1 parts to do the upper ball of the front MacPherson, that's also what I have found for my Escort. In my case I also used the part surrounding the ball, cutting off the remaining plastic and was left only with a small plastic receptacle that I had to somehow hold to the chassis at the top.

I got the idea of using F1 parts from your thread. First I was going to use same parts as you did but I found out that Xray F1 car used a bit smaller parts (6mm balls) and they didn't need any modifications. Also those Tamiya parts you used were harder to source. Xray parts were in stock where I do most of my RC shopping.

https://fi.eurorc.com/product/10541/xray-x1-composite-arm-bushing-4


Shocks from 1:18 Losi mini late model are very small and are a nice fit for scale 1:10 look. The springs are very soft and they have a threaded body so if it is a bit soft and the rear sags you can cheat with some more pre-load. In the pic they look just like regular 1:10 buggy shocks, but they are much smaller.


http://www.losi.com/Products/Feature...rodID=LOSB1289

Those look nice! But it seems like they are discontinued. The rear of my car uses standard touring car shocks and springs and it got way more softer once I added some green slime and oil in the shocks. The front is nice and soft also and I have an assortment of springs at hand but I'll have to tinker with the suspension more when I have all the electronics in place and some weight on.
 

Ghostpig

V.I.P. Member
Got the motor installed.

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Front sway bar is in.

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Electronics layout.

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I'll swap the servo to a standard size one and maybe I'll go for a smaller 3s lipo for better weight distribution. Also fixed the steering tie rod bind issue by adding some spacers under the rod ends. It eliminated nearly all of the bump steer too.
 

Frederik

Supporting Member
Your front suspension with the integrated sway bar and all looks pure awesome! Did you mention what size motor this is? It looks slightly smaller than regular.

Having the transmission tunnel makes it a bit difficult to find a good weight balance for the battery. Do you really need 3S? If you could do with 2S, in my case I went with 2S saddle pack so it is two separate 1S cells, and I place them one each side of the tunnel, under the seats.

I love how this is taking shape, keep it going!!

Fred

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Ghostpig

V.I.P. Member
Thanks Frederik! Your Escort build is pretty awesome too and I've been eyeing it quite some time and got plenty of inspiration and ideas for my build.

Motor is standard 540 size brushless 13,5t. And for current wise I definately don't need a 3s. I do have a couple 2s saddle packs and two super shorty 2s lipos that I could use. My saddle packs are quite old though and I don't know how much they got life left. And I'd like to keep the electronics layout simple. Not too much wires crossing from side to side. But there's some lighter 2s shorty packs available, maybe I get some of those.
 

Ghostpig

V.I.P. Member
Thanks everyone!

Here's how the diff goes together.
The pinion and ring gear are from SSD, locker is 3d printed to fit Tamiya TT-02 joints. M1.6, M2 and M2.5 screws. I used some dumb sized bearings that I didn't have while designing the locker, so I had to use styrene tubing to fit the larger bearings but it works though. Needs shimming.

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Here's the gearbox.
RC4WD R4 transmission gears, M2.5 screws.

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Caprinut

Member
That diff and gearbox is genius!

I need to do something similar for my planned T3 Vanagon Doka build regardig the diff.
 

Ghostpig

V.I.P. Member
Thanks Caprinut!

Did I mention that there will be an opening bonnet? No? Well it will as I have cut it open. Also made a mock up of the roll cage. I used some styrene tubing that I had. Final version will be brass tubing or brake line, 4mm or 5mm od. This one is just to see the geometry and dimensions.

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Frederik

Supporting Member
Very nice to see the chassis with cage under the body! The cage will probably help a lot for the stiffness to the chassis pan. The opening hood will be a very nice feature! Do you plan for a detailed engine bay in there?

Oh and that transmission and diff design does look purely awesome, as the rest of the mechanical bits. It truly is an awesome chassis!
 

Ghostpig

V.I.P. Member
Thanks everyone!

Very nice to see the chassis with cage under the body! The cage will probably help a lot for the stiffness to the chassis pan. The opening hood will be a very nice feature! Do you plan for a detailed engine bay in there?

Cage will help a lot but the chassis isn't too floppy without it either. The black parts, floor plates and central tunnel, stiffens up the chassis quite a bit if bolted on properly. But the rear shock tower needs dome additional support.

And yes, there will be a dummy Nissan S20 engine and some other bits too, like an exhaust piping. I also have led kit to go with the car.
 

Ghostpig

V.I.P. Member
Got the roll bar done. 5mm brass tubing soldered together.

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Next I'll try to get this moving and then I should focus more on the body and scale stuff.
 

Frederik

Supporting Member
Very nice work on the cage! From the pickup point on the rear suspension, it looks like it will do great for rigidity, and it has a nice tight fit under the body.
 

Ghostpig

V.I.P. Member
Very neat!

Thank you!

Frederik
Very nice work on the cage! From the pickup point on the rear suspension, it looks like it will do great for rigidity, and it has a nice tight fit under the body.

Thanks! The chassis is now super rigid and the rear suspension is now nice and soft. I got some softer Yokomo drift springs.

Anyone have any tips and advices on how to mount the body? I'd like to do hidden body mounts like magnets or velcro or perhaps a hybrid version. I need to get the body firmly on place. The opening hood adds it's own troubles to this. If I mount the hinges on the chassis, I'll need to be extra careful with the body alignment. So I'm kinda leaning to adding a cross brace direcly on the body and mount the hinges there so the body and hood is one piece.
 

Ghostpig

V.I.P. Member
Time for proper scratch building not just 3d printing!

I plan to add some details to the inside of the hood/bonnet. That means I might have to paint it from the outside but I'll come to that later. The complex curvature of the hood is a bit of problem. I can't just design a part that would fit perfectly and if I make a flat piece that is forced to the shape of the hood, I fear that it would mess up the original shape of it. First I thought I'd do the details with Green stuff or similar malleable putty. But I scrapped that idea too. My current plan is to do the details of thin sheet of metal.

First, I made a buck/mold of 1.5mm styrene sheet. It still needs to be sanded smooth.
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Then I made a mock up using regular household aluminum foil. I folded it once to get some thickness. I used a cotton swab and a dovel to press the sheet against the buck. I attached it to the hood with tape to see if it fits and it looks good. I think my plan is working.
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I'll leave some extra to the front of the hood and shape it later. Next I'll need to get some thicker but still thin sheets of metal, perhaps a tin sheet or something like that. If this doesn't work, my back up plan is to heat form the buck to fit the hood.
 
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