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Fabia130vRS

Tamiya F103GT/F104GT MINI, DIY (タミヤ f104gt)

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Has anyone yet created (or got their hands otherwise on) usable CAD files for a M-M chassis and upper deck?

I tried making my own chassis from a fibre plate, and the drawing went just fine. But since I have no box culomn drill I used a hand held one, which resulted in holes that were slightly off (although I marked the right spots with a centre punch). So it got me a wheelbase of 226mm on one and 224mm on the other side - won't try to drive that :lol:. Did I say it wouldn't be too hard? Hmm...

Unless I can have a chassis made professionally, I won't attempt it again. As I want to race it, it should at least run straight. I'll take care of erratic driving myself. :P

Hence the question if anyone might have usable CAD files to send to fibre-lyte or such.

@Fabia130vRS: Did you manage to make a chassis or have one made? If so, would you share your experience?

Loking forward to your replies.

Cheers,

Jan

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Yes, I did use a drawing yogi bear has sent me, some holes did bot fit. So what I did, I printed his drawing on A4 size paper/sticker, cut it out wih scissors, and did paste on a hard wood plate (wood glues together under force like a skateboard deck). I used a hand saw, to cut it to shape, and a dremel to smooth the edges, also I did use the original f103 plate to drill proper holes.

Niw that I have a plate, I move forward, havent checked the wheelbase, by calculations should fine, but still I am collecting parts, as for front and rear. After that I will trim the width to 160mm. 

I am fine by the idea of having a wood chassis, really light and flexible, will see how good flexible really is, but also I will use glass fiber, 1 layer on each side should be good to go.

I did not know about the F104 diff joint, havent got to it yet but good to know, that is probably the last part missing as for completing this model.

still over winter I will have my home office room setup, and will get a CAD drawing program and teach myself. Found a few people in my country, they do cnc cutting of plastic and carbon.

here some pictures what I have by now.

 

11tuant.jpg23sivt3.jpg2n1gha1.jpg5334fc.jpg2u9s9jp.jpg5ug046.jpg

so, resume, waiting for front and rear axle parts, trim to 160mm width, check wheelbase, buy a body, trim front bumper or remove... etc :)

 

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@Fabia130vRS: Thanks a lot for sharing your pictures. Looks very good what you did there, will be interesting how the wood handles.

The idea to use the original chassis as a drilling template didn't occur to me :wacko: - that might do the trick to get the holes lined up properly. I drew on paper, cut it out and glued it to the fibre plate. That and the cutting went quite well, I just botched the drilling. Maybe I'll try again after all.

But like you I also thought about learning CAD, which might be used on other projects, too. Will have to look into that.

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5 hours ago, yogi-bear said:

if anyone else wants it, here is a link to the drawing, let me know where the holes are out and I can correct,

https://vintagerc.com.au/wp-content/uploads/2018/09/F104GT_chassis_plate_cleaned.pdf

Here is how it needs to be.

I hope it looks clear. The lower two holes are good.

also in overall lenght, we should add in middle about 2mm, ruff measures indicate a 223-224mm eheelbase.

243qj3s.jpg

 

I am glad there is so much interest, I also like the idea of Speedy, to use a rm01 but I have most parts from F1 and knowledge about compatibility so stuck to what I have saw already being done.

 

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@mailboxck, I was windering could you send some measurements of the rear? Like from motor mount to top of tip? On both sides?

to make it easier to us and possibly less expensive, what is the lenght on the spacer on the right side? The diff needs to be 22-23mm?

33dy0r5.jpg

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@yogi-bear: Thank you for offering the picture. Don't know if I will use it though - if I try again, that is - as I was thinking about a wider chassis in the front to be able to lay the servo down. I once had a F1 (maybe F101?) with that kind of layout. Will have to see if and when I get around to try this again. But still am very interested in such a modified chassis. Was about to sell my F103GT when I saw this post.

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What motor do you have in your F103gt @NeonScorcher?

Tamiya F102 had the servo in laying position, also I believe there is a TRF model with such a position.

I am using a 1/16 metal gear digital servo, I had the smaller servo kount at home, and now I even have soace left for all electronics and a gyro device in the middle.

since I am plannin on a 10,5T brushless setup, once this is finished and fiber plate instead of wood.

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@Fabia130vRS: I had a 10.5T in it, which was almost too much, 13.5 should work well. The gearing is quite limited.

Like you mention space is tight which made me think of a slightly wider chassis. I was also thinking of using a 1/12th servo, there is not much weight to move at the front. Let us know how your 1/16th servo holds up once you drive it.

A really interesting project - I will have to give it another try.B)

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As requested, here are the measurements of the rear end.

Spacer length = 8 mm (Made mine from some unused plastic sheet I rolled into a tube)

42204400_268783480639715_3480028574780489728_n.thumb.jpg.877a67b1be882bb71d497151e851d5f0.jpg

Shaft length = 106 mm (Hacked original steel shaft)

42201306_240373133299831_4339494029411483648_n.thumb.jpg.ebe0e202e3a01361635c31b4a0984d12.jpg

Diff height = 35 mm (DIdn't have time to disassemble the whole thing, but once you put it together, it should be around 35 ~ 36 mm tall.42202779_2212419359082406_6467016009449472000_n.thumb.jpg.b5f1a782bd20b24fd41217781cdd1d6d.jpg

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6 hours ago, NeonScorcher said:

@Fabia130vRS: I had a 10.5T in it, which was almost too much, 13.5 should work well. The gearing is quite limited.

Like you mention space is tight which made me think of a slightly wider chassis. I was also thinking of using a 1/12th servo, there is not much weight to move at the front. Let us know how your 1/16th servo holds up once you drive it.

A really interesting project - I will have to give it another try.B)

I had this 1/16 servo in my DT01 buggy, its with metal gears and really strong and fast for its size.

but you dont need a hardcore servo in such a chassis, I use in my f104 a Trackstar with Nylon gears inside, bought new for 6$.

Also in my F103 (with f103gt motor mount) I have a 35T pinion and 93 Spur, that gives a FDR of 2,65. On 13,5T which is inside, really fast. But not 3s fast. Thats why I would put in this mini a 10,5 without doubt.

 

@mailboxck, thank you mate, that is what I needed. The rest I will figure out. 

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Today I shortened the rear axle, well, I figured, if the steel 114mm axle needs to be cut to 108mm, I could also use the hop up Carbon Rear shaft for F104 models, that is 110mm, since the rear diff shaft of the F104 pro will be needed, its a perfect fit.

The cutting of the F103GT diff housing reminded myself why I hate this DIY build, drilling a 11mm hole without a 11mm drill was sort of handmade with a hobbu knife and 9mm drill. also a lot of sanding the edges, 2mm spacer were needed on the end since I shortened it for just about that much.

Finally 165mm width accomplished. A 70T Spur used with this motor and 18T pinion was a tight fit, so I went for a 18T pinion and 63T Spur. Since I dont want to overheat the esc, esc limit marked is at 23T, but many have said that under low resistance it was able to hold a 19T-23T engine.

Waiting, for front uprights F103GT, front arms F104 and its complete then.

I have the special king pins and front axles in aluminium blue and orderd steel axles as for the M03 (rear) in silver. 

 

k1ctut.jpg

1znqxvk.jpg

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Great work! Congratulations.

Haha. Yeah, I also couldn't find a 11mm drill bit. Had to use a 10mm bit with sandpaper wrapped around it.

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6 hours ago, mailboxck said:

Great work! Congratulations.

Haha. Yeah, I also couldn't find a 11mm drill bit. Had to use a 10mm bit with sandpaper wrapped around it.

Todays test has given these results, 

it indeed needs to be a 108mm rear shaft, I did cut of mine 2mm, since the F104 diff shaft couldnt go to the end, and also I needed to widen the flat spot for the hex screw to fit to the shaft.

now perfect, but I knew the F103GT cutting would have consequences, I did not cut the diff even and now its wobbleing 1mm and making vibrations, nothing already seen on the F1 tho when you hit the wall with a wheel and starts to wobble. I definately will buy a new F103GT diff and I have another wheel carrier, and I will cut them at our club, we have machines for it to make it precise and balanced. that will be on the final model since this is more of a concept. 

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Managed to make a upper deck out of the same material as the chassis.

it feels only by picking up the car with hands that there is bo flexing. All nice and stiff. 

2qxuw76.jpgdsgo1.jpg120sbdh.jpg

Waiting still for front uprights and rear body mounts to arrive 

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Yup that was the idea. I wanted to order gpm aluminium uprights, but then I saw they come together on the parts tree with body mounts. It will look pretty original when finished.

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Some F103GT porn:

null-31

And my own attempt at a shortened chassis wasn't quite so extreme, just the correct wheelbase for the Porsche 934 body. And I still haven't finished it :lol:

2018-10-12_09-39-15

 

 

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2 hours ago, ChrisRx718 said:

Some F103GT porn:

Looks good. Reminds me that I really need to take mine out of the box and start the build on it. 

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Just sharing some tips. When I raced my F103GT before, I would swap between the long upper deck (the one that stretches all the way to the servo mount) and a short upper deck from an F103RS. If you need more grip, use the shorter upper deck.

Also, if that's not enough, change the o-ring in the t-plate. The manual says to use a washer in the front hole and a black o ring in the back hole. You can swap those for a red o ring (softer) if you need more grip.

And yes, changing to an oil filled center damper does help a lot.

Lastly, forget the F103GT's 2 spacers under the motor mount. No need to use it.

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Trimmed yesterday the front uprights from a F103GT, but it seems it will be really a tight fit, orderd a F104 carbon reinforced uprights and GPM aluminium Hex 12mm adapters with bearings. Should fit perfectly.

zo7xgl.jpg

2ql7hpv.jpg

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Nice job with a lots of work. I have the little Honda but in plain street mode. No decals. 

F88D9241-5612-43AA-804C-A7E9405D9255.jpeg

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Mine's not as short... 

DSC_04752

I'm gonna have to try and find a buyer though as I simply don't have the time these days to finish stuff!

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20 hours ago, mailboxck said:

Do you have any suspension travel left upfront?

No, havent got time these days, to trim the upfronts properly. I need to shave off about 3-4mm.

But since I probably wont use M chassis rims, I also will try with standard F104 king pins and f103gt uprights. Having the spring on bottom.

 

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