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ThunderDragonCy

RWD Touring Car Design Concept - Would appreciate thoughts

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As I have my TRF211 3 gear laydown transmission parts spare, I have been wondering about a bit of a project to make a proper RWD touring car, rather than rally car. Mid-motor, shorty, that kind of thing. 185mm track width, 257 wheelbase. Spent a bit of time this evening getting a few ideas out of my head. Would appreciate some thoughts. It's basically a 1/10 M08. Would be 3mm carbon chassis plate, sideways shorty, everything mounted longitudinal like a 2WD race buggy. Thinking TA07 steering, possibly flipped around to pivot between the suspension arms.

RWD TC V1 iso RWD TC V1 SIDE RWD TC V1 TOP

Not sure if it's a goer or not. Not sure if it's even legal to race, although FWD touring cars are allowed. Any thoughts? 

Cheers!

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You're somewhat heading in the same direction as a 3Racing Sakura D4 RWD drift chassis.  Central motor placed ahead of the rear axle, central transverse battery, RWD only...  The key difference you have is the placement of the servo and ESC.  You can save some room by placing the receiver on top of the servo.  You may want to dedicate some room for a gyro like the GC301 because RWD cars can be tricky to throttle coming out of a turn.  Braking gets interesting too with no front brakes.  (F103GT experiences)

I took a Sakura D4 AWD kit, deleted the rear spool, moved the front gear diff to the rear, and changed the layshaft pulley and rear belt to make it work (17T pulley, 39T gear diff, Sakura D3 rear belt).  I mainly bought the AWD kit instead of the RWD kit to get a gear diff less expensively than a separate parts kit.  My original intention was to make it RWD and design some front mechanical brakes, but I lost interest and added a 38T front one-way (w/ 16T layshaft pulley) with the original D4 center/front belt.  (Showroom entry)

Also take a look at the Thunder Tiger TS2e.  Similar concept to what you're showing with flipped servo/ESC positions.

From my point of view I'd want to get the motor and battery as close to the rear axle as possible for more weight over the driven wheels, and I'd want a gyro for the front steering to help reduce the risk of spinning out.  I'd also want the front mechanical brakes or something similar to take advantage of the weight transfer when slowing down.  The TS2e is limited by its front suspension; a normal touring car suspension with oil dampers would help some.  The D4 RWD might be a better starting point to test some concepts.

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I can't seem to edit my post, but for a historical perspective also consider Associated's RC10DS (Dual Sport) RWD touring car:  Manual

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@speedy_w_beans Thanks for the input. Hadn't thought about a gyro. I hace noticed my rwd rally car can be a bit of a handful on the throttle on the loose, but on higher grip its good. I kmow what you mean about weight on the rear, but the laydown doesn't do that, it's all about getting the weight central. Don't really want to do another transmission, so might be fun anyway. Laydown buggies are all about corner speed. Maybe wider rear tyres might be good, or stickier rear than front?

 

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Maybe; I think @Raman36 has mentioned in the past he was able to tame a M06 or M04 with wider rear tires.  Maybe he can comment on your CAD rendering with his experience.

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Think this is a really interesting concept but it's definitely going to be the stopping that's going to be the hard part. My M-06 just wants to swap ends if not set up just so on the brakes. I'm sure someone here had a 4wd chassis with a one way bearing flipped in the front so that it was rwd when running forward but as soon as the brakes were applied the car became 4wd. I may be completely wrong of course! Not sure how that would translate into a rwd chassis though. 

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1 hour ago, Grotty Otty said:

Think this is a really interesting concept but it's definitely going to be the stopping that's going to be the hard part. My M-06 just wants to swap ends if not set up just so on the brakes. I'm sure someone here had a 4wd chassis with a one way bearing flipped in the front so that it was rwd when running forward but as soon as the brakes were applied the car became 4wd. I may be completely wrong of course! Not sure how that would translate into a rwd chassis though. 

That flipped one way was sometjing i was thinking about this morning. Thanks for the insight on the m06. I did wonder how they handled. 

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If there a one way available for a TA03F? That way you get the advantage of the motor over the front wheels, which may help cornering.

 

Also it may be worth considering if you can get F103 wheels/rubber tyres to fit. Would be a heap more rear grip.

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For touring car, it seems to be a bit too complicated.

I think that RWD benefits from direct drive and low weight. Something like MST TCR in MR configuration, but with proper damping would be interesting. It's too bad that Losi is not making JRXS anymore, some parts could be used for that.

I was also thinking about RWD with de Dion type rear suspension. Although it's not  independend suspension, it has certain advantages over classic live axle found in traditional RWD cars, while being much simpler than independend suspension.

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51 minutes ago, Honza said:

For touring car, it seems to be a bit too complicated.

I think that RWD benefits from direct drive and low weight. Something like MST TCR in MR configuration, but with proper damping would be interesting. It's too bad that Losi is not making JRXS anymore, some parts could be used for that.

I was also thinking about RWD with de Dion type rear suspension. Although it's not  independend suspension, it has certain advantages over classic live axle found in traditional RWD cars, while being much simpler than independend suspension.

Whilst the lack of front brakes is a disadvantage i think i agree with you, than main reason i think this is intereating is because it could be so light compared to a 4wd. Maybe some front kickup to neutralise some of tje weight transfer under braking would be good? Not thinking buggy levels, but if 4-6 deg front caster would be useful, maybe achieve that with kickup instead of angled c hubs? 

Does anyone know if front wheel drive touring cars are allowed to run at a lower weight than 4wd whwn racing? 

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Check out the Yokomo YD-2, it's all the rage in drifting now and they got some good ideas for getting traction to the rear(If you're on hard plastic tyres but wnat to be quick, you need every trick in the book). They also used a 2WD buggy tranny with the motor spinning towards the back of the car to use the inertia for grip. And there's the Carb-D conversion that mounts the motor above the diff for better weight distribution:

35524859_1073838166096769_50648311557867

I drove one, and the handling is surreal, it's virtually impossible to spin. Granted, the high CG might be less ideal on a touring car.

I like the idea, RWD grip racing has also crossed my mind a couple of times. Would like to see it take of.

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10 hours ago, _oliK said:

Check out the Yokomo YD-2, it's all the rage in drifting now and they got some good ideas for getting traction to the rear(If you're on hard plastic tyres but wnat to be quick, you need every trick in the book). They also used a 2WD buggy tranny with the motor spinning towards the back of the car to use the inertia for grip. And there's the Carb-D conversion that mounts the motor above the diff for better weight distribution:

35524859_1073838166096769_50648311557867

I drove one, and the handling is surreal, it's virtually impossible to spin. Granted, the high CG might be less ideal on a touring car.

I like the idea, RWD grip racing has also crossed my mind a couple of times. Would like to see it take of.

The interesting thing there is that everything they have done is the opposite to what this transmission and everything about modern high grip 2wd buggy racing does. Older bughies where like the drift car -  loads of weight on the rear, even rear motor. Early mid motor buggies were 4 gear to get the motor augmenting grip as you say. But as time has gone on, understeer is the enemy in 2wd buggy, but with the big spike rear tyres rear grip is less of an issue, hence things like my 3 gear laydown transmission above. Moves weight forward, and the motor rotation drive weight transfer to the front on the throttle. If i do this i think the key is going to be getting the tyre grip balanced front to rear. Interesting stuff though. Thanks. 

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Then maybe the battery in the center is indeed the way to go. I imagine that would make it very agile.

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All this RWD talk has got me enthused to get my TA-03R off the wall and put a reversed one way in. Will be interesting to see the outcome. Once I get all the parts put together I'll start a thread.

I have some 30mm foam wheels/tyres that will hope fully give it enough grip (front and back), also have some tamiya slicks I can test with.

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18 hours ago, ThunderDragonCy said:

Does anyone know if front wheel drive touring cars are allowed to run at a lower weight than 4wd whwn racing? 

As far as I know the weight limit is removed for front drive touring cars in the standard classes. Of course this depends on where you run but in my experience rules are pretty standard even in different countries. In saying that I haven't seen a fwd touring car race since the 90s when a kid ran an FF01 Mondeo which was insanely fast in a straight line.

I have a rwd mid motor touring car from the 90s. Its a Kyosho Mantis and was the entry class back then. I could post some pics if you like. I don't know how long the type lasted but the big issue wasn't the rwd and mid motor, it was the suspension which i'm pretty sure was unique to this car and for good reason hasn't been repeated.

I like your concept, with my only concern being that this is distracting you from the DB03

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@Jonathon Gillham Thanks for the info. That's really good to know because it puts this in an interesting place. I weighed my TRF211 at the weekend and it was 100grams underweight. This really surprised me as it has no trick bits or ti bolts at all. This thing could be seriously light.

Really need to try and get my head around touring car wheels and tyres. 

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