An SRB design debate

[Saito 5]

I remember reading in a review long ago that suggested the SRBs were based on fullsized VW-type off-roaders because Tamiya didn't really know how to go about building an off road RC vehicle at the time. The idea was there were no real RC off-roaders around to copy. The few that were around didn't work all that well and were mostly on-road cars poorly converted to off road with big tires and not much suspension. Tamiya, being inspired at the sight of full-size off-roaders, fell back on what they knew...making smaller versions of the real thing. Now, on one hand this theory makes some sense. They didn't bother making the actual chassis of their previous on-road cars realistic, just the bodies (which after all were cribbed from their scale model brothers). On the other hand maybe the SRBs are so close to their full-size counterparts because Tamiya always liked scale modeling. So what does everyone think? Were the SRBs meant to be highly realistic (like the original 3-speeds boasted on their boxes) or were they that way because Tamiya was breaking into a new market with not much to go off of?

[B.M.T. 127]

I think it stems from their desire to make a scale off road buggy, personally. However, it does baffle me why they went single A arm on the rear instead of trailing. Maybe it is as simple as the VW flex plate set up was too complicated to get flexibility vs. strength working in 1/10th. But, they achieved the optical result in the finished product.

Also, I don't believe that racing was even in their thoughts at the time. That came about as a result of people's nature to compete with anything that they can get their hands on, like lawn mowers for example. They just made a model dune buggy and Baja bug you could take to beach and emulate the action of the real ones with.

However I do think the F150 was Tamiya's first major lazy!

[dragnse7en 9]

From what I've been seeing, especially after the re-release of the Sand Scorcher, the SRB scene has exploded big time. This forum is full of the best minds behind restoring, fabbing, or modding this particular platform.

To answer your dilemmas, no. Kabushiki Tamiya himself started his model company briefly after WWII, with wooden models that were super detailed. After the invent and discovery of plastics, he went into another direction, and made the very 1st hobby-grade RC car, complete with a list of upgrades and replaceable parts.

You should really google Tamiya 1st, before you asked this question. All the answers are there on the Wikipedia page.

Tamiya has always looked closely at real-size cars, and they both emulate them, and make innovative designs so cutting-edge, that they own over 1,000 patents on their own rc part designs, including the oil reservoir shocks on the 1/12th scale Rothmans Porsche 959, the trailing arms on their Frog, and the leaf-spring suspension on their F-150 Ford original Hi-Lux. I can go on, but I will digress.

If you're looking to restore a Tamiya car, especially an old one, look for a bio-degradeable degreaser, such as Simple Green, some hydrogen peroxide bottles and a UV light source to whiten old parts, and a good handy set of tools, a drill, a dremel tool, and replacement oils and greases to acommodate your specific project.

Good luck on your endeavours

[Saito 5]

Um, I was merely trying to start a discussion based on the opnions of those here on the site not get a definate answer to a question. Personally, I don't care if there is a right or wrong answer, just what people might think. Wikipedia is not the final-word bible for all answers. I'm not sure what cleaning products and restoring Tamiya models has to do with this discussion but thanks. I have well over 30 restored cars in my collection currently.

I always felt it was more of a scale design rather than what the old magazine review I mentioned suggested about off-road design. Still, the F-150 was far from scale and that was very lazy, very early on. They went to the trouble of doing up a body but not an appropriate scale chassis.

[dragnse7en 9]

Wow.

Okay, so fine and be it. I tried to help you, but apparently thats not good enough for you.

I only tried to answer your questions the best that I could.

good luck from now on, but not from me anymore.

[B.M.T. 127]

^ You should Wikipedia forum discussion. You need to learn what it means.

As for Wikipedia, and if you believe all you read on the internet, Shakira's She-wolf song is a cover of the Megadeth one

[dragnse7en 9]

^ You should Wikipedia forum discussion. You need to learn what it means.

As for Wikipedia, and if you believe all you read on the internet, Shakira's She-wolf song is a cover of the Megadeth one

OMG

have a nice day.

As I said, I was only trying to help.

wow. - nice reply.

[RichieRich 685]

Relax guys. I don't think dragnse7en meant anything negative with his wikipedia comment. Though, it is worded poorly. Give people the benefit of the doubt. Generally, no one comes here with the intent of being a jerk.

[Bromers65 1]

I'm not getting involved in the cafuffle above, i'm here to talk design

As far as whether Tamiya were copying the full size VW chassis because they had nothing else to go on or they were copying it because of its simple and clever design, i'm not sure. Personally i think they copied it for a bit of both reasons.

The rear set up on a 1:1 VW chassis (swing axle with torsion bar running parallel to back axles), i doubt, would be strong enough scaled down. There would also be the issue of flexibility against strength. These little buggys take a heck of a bashing! I think the design they came up with is a good compromise, as stated above, giving an overall similar appearance once assembled and the body is on the buggy.

For me, the real genius in design, was the front axle assembly. This is so close to the 1:1 vw front beam assembly its uncanny. The only differnce is the way it is sprung. The SRB of course has a wire spring at each end of the assembly, where as the actual 1:1 has 2 torsion bars (made up of individual leaves) running through the two tubes attached to the trailing arms at the end. Apologies for all you VW savvy people out there, if i am teaching you to suck eggs, but thought the non vw educated may find it interesting

From these diagrams you can see how close they got it, and also how difficult it would have been for them to spring it the way the 1:1 assembly is sprung.

Overall, i think the SRB is a spot on replica of the VW chassis, compromising between design, function and ability to mass produce at good costing. Sure they could have made it a perfect replica, but this of course wouldnt have been cost effective. thats my two pennies worth, not a difinitive answer, but what i think of their design

[KyoshoTomahawk-SRB-Dan 0]

Hey there Bromer65

Thank's So Much for The Wonderful Pictures of the VW

From looking at the second Part of the Diagram

It makes me wonder how hard it would be to build

a SRB with A TRUE STEERING RACK UPFRONT

I can see the Steering Rods and it looks like there is a steering damper to the right

then the rods come together where i expect the steering Rack and Pinion would be

So ! How about we get a Small electric motor Like the one From A Scalextric

With the standard Scalextric nylon Cog,,,and use it to drive the Rack Mechanism which we would have to make

as a Scratch Build ,,

that the hard part

but how it would be controlled is just a small lo power speed controller and set it up so it is Backwards for Left and Forwards for Right

Wowsers I Would just love to see that ,,

My Scratch building Skills Are not much but,, kno What

I am going to give it a Go

Thanks So much Your post gave me A Fabulous idea and a cool Project to work on

Heeee !!!!

[bromvw 744]

Not a bad idea that . RACK AND PINION . Maybe the old MSC would be ideal to give forward / reverse to the steering drive motor rather than using a servo ?i might mock this up with lego and see how well it works

[caprinut 0]

Not a bad idea that . RACK AND PINION . Maybe the old MSC would be ideal to give forward / reverse to the steering drive motor rather than using a servo ?i might mock this up with lego and see how well it works

I will just say that the 1:1 beetle uses a steeringbox, not a rack and pinion..

But if you want to go rack and pinion on this or a another project,tamiya has allready made that, you will find that in the Big Wig

[bromvw 744]

Anyone tried fitting the Big Wig steering to a Blitzer ???????????????

[Scorchio 139]

@ Bromers65, nice post! may I ask where you got those diagrams? I could do with some for rear end if available .

Personally with the SRB thing I think its clear tamiya had a specific car in mind when they developed the Rough Rider based on the Belray Bullet, which is actually a a Funco S2 sand rail.

http://www.tamiyaclub.com/showroom_model.a...6&sid=12565 Thanks BB.

So then they've got this chassis which is also scale correct for a Baja, no one has found EXACT historical pics of what the Scorcher was based on but it follows the general trend the class 5s did of that time.

The front shock towers have always been massively oversized on the SRBs in terms of scale but I think thats entirely down to strength and durability, as exact scale shocks would not last a minute. This would possibly explain the single swing arm rears in terms of ease of manufacture and strength ect.

To conclude I'd say their priority was towards scale RC rather than racing as such.

[jubaluba 0]

A fantastic rc model of my all time favourite car.

If I remember correctly (don't take my word for it) it was based on a 1968 model.

The front suspension even has the ball joints mounted almost the same way as the real one.

It would be exciting to see a perfectly scale steering setup. And off course see it being driven.

After all the beetles with the torsion beam front end has some of the same bump steer issues as the Hotshot.

As for rack and pinion steering, the 1303 beetles from 1975 and up has rack and pinion.

But it also has a completely different front suspension with mc.pherson struts.

But that would also be an interesting SRB procect.

[Live Steam Mad 17]

After the invent and discovery of plastics, he went into another direction, and made the very 1st hobby-grade RC car, complete with a list of upgrades and replaceable parts.

Are you referring to the Porsche 934, the first Tamiya RC car model? In which case Shunsaku Tamiya was the boss of Tamiya at that point and he asked Fumito Taki to design the chassis of the 934, the body was from the already existing 1:12 static model that they already made.

I remember that from reading Mr. Tamiya's biography (English version).

We also have confirmation that Fumito Taki designed the Sand Scorcher and Rough Rider (Buggy Champ) as there was an article in a UK magazine that is available online as scans (and I have a copy of the magazine itself) with him in interview where it tells us that Fumito designed that and other ones too like HotShot, Avante, etc.

LSM

[hedge 314]

I remember reading in a review long ago that suggested the SRBs were based on fullsized VW-type off-roaders because Tamiya didn't really know how to go about building an off road RC vehicle at the time. The idea was there were no real RC off-roaders around to copy. The few that were around didn't work all that well and were mostly on-road cars poorly converted to off road with big tires and not much suspension. Tamiya, being inspired at the sight of full-size off-roaders, fell back on what they knew...making smaller versions of the real thing. Now, on one hand this theory makes some sense. They didn't bother making the actual chassis of their previous on-road cars realistic, just the bodies (which after all were cribbed from their scale model brothers). On the other hand maybe the SRBs are so close to their full-size counterparts because Tamiya always liked scale modeling. So what does everyone think? Were the SRBs meant to be highly realistic (like the original 3-speeds boasted on their boxes) or were they that way because Tamiya was breaking into a new market with not much to go off of?

My guess (no facts inferred ) would be that given these where the 15th and 16th cars produced by Tamiya, that they felt it was time to do a full scale model. Up to this point only the bodies where scale, and lets remember they where only sold as "Suitable for Radio Control"

So my guess is like all good things it was an opportunity meeting with luck. Tamiya thought off road, saw the old Bel Ray FUNCO buggies and thought we can not only do the body but we can pretty much do the chassis as well. Of course in reality the matching of scale components in an unscale environment was not a match made in heaven but it did make the most iconic RC car ever.

####

Please note if any of the above is found to be factual or appear in wikipedia it is a complete coincidence.

[Bromers65 1]

@ Bromers65, nice post! may I ask where you got those diagrams? I could do with some for rear end if available .

Scorchio, they were obtained through google images, just put in what you are looking for and sift through the hundreds of images til you find what ya want. Something like "Rear VW beetle suspension diagram" should get you close to something you are after.

[wolfdogstinkus 1893]

Has anyone tried to fit sway away adjustable front suspension to their srb?

Not sure it would work on an srb as the torsion bar doesn't run the whole way through the axle?

Might work with a mini servo to have adjustable front suspension?.

[TomEG 24]

As for rack and pinion steering, the 1303 beetles from 1975 and up has rack and pinion.

But it also has a completely different front suspension with mc.pherson struts.

But that would also be an interesting SRB procect.

The 1303 S also had double jointed rear axles, like the Porsche 911 ;-) to keep the camber even. I loved that car, my first one was a 1972 1303 S in metallic blue, and my last one is a 1983 911 Turbo in Guards red (indian rot) ;-)

Tom

[Scorchio 139]

@ Bromers65: Ah! Did try it but I must trawl harder it would seem Cheers mate.

@ Wolfdogstinkus: SRB Is pseudo torsen, so to get the effect shave some of the stopper off the top swing arms (if slamming really low) and bend the spring in on itself, then put shorter shocks (SRB rear shocks) on the front as you would with 1:1. Sway aways clamp and rotate the torsens inside the beam so doing that to SRB swing arm pins would just lock up the suspension.

[wolfdogstinkus 1893]

I don't have an srb so wasn't sure of the set up inside the axle beam, I just thought it would be really cool and scale to have sway aways.

Thanks for replying scorchio I think you explained it well.