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Old 23-10-2011
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Default GT14B Rear Motor chassis - Switch Hitter

After a year of running the GT14B i started to think of how it could be improved and ended up designing a new chassis - the switch hitter.


The key concepts behind the Switch Hitter are:

More even weight distribution (and hopefully improved handling)
Increased battery space
Increased flexability for electric installs.


Weight balance is the key, as the entire chassis stems from here.

One of the signature parts of the GT14B layout is the saddle packs, which in a 16th scale car, forced the motor to be placed at the front of the car, in this case front right.

With the motor weighing close to 90g, it always seemed to effect the handling by pulling the car right under acceleration and causing it to be a tad nose heavy in flight. (at least i thought it did)

so, as i've never been wedded to using saddle packs, what happens if we rotate the motor mount by 180deg and have the motor at the back left?

okay so it's not rocket science, but it should be easier to balance the car with the motor on one side and a lipo on the other at the rear.
I'm hoping that this configuration will also take the bite out of the steering, making it an easier drive and provide a better front/rear weight balance.

Those of you who are awake will have noticed that this means you have to run a single pack lipo, but i don't see this as being an issue, especially as the saddle packs are costly and hard to get hold of.


quick recap then;

1) weight balance - check

2) larger lipo space - by altering the layout and having the longer drive shaft to the rear of the drive train, we can fit a lipo of up to 65mm between the posts (and probably 75mm if you take the posts out).
a quick look around has thrown up lipos of up to 1300mah that will fit, more than enough juice i should think.

3) ease of electric installation - check! with no motor up front, the servo can go on either side, with your esc of choice and rx as well, no need to mount it on the top deck.

for pics, check out some out on Photobucket,HERE

and you can buy the conversion from Team RCMI HERE

oh, and the name? Well, it's october and i've been watching far too much baseball.
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Old 23-10-2011
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First Test:


Started off with the setup i was VERY happy with from MicroX on the std chassis, albeit with a little less weight. 792g to be exact, 44/56 front/rear balance, 5g lighter on the right.

From the off the car was noticeably different, a little loose mid corner, but less twitchy and far easier to drive.

for the next run i swapped out the 3deg alloy rear block i was running and went to the the stock plastic block, much better.

The car felt much more compliant than before, less nervous and easier to drive, yet with no loss of steering.

the crazy front end grip was gone and i was comfortably running on the stock (outer) ackerman hole, which was far too crazy for me on the std car.

Rick (dombrasky) and Kev Taylor, who both have the GT14B, both ran it back to back with their chassis and gave the same feedback, smooth and easy to drive, lots of rear end grip and far less twitchy than before.

Mr Speedy also had a go and seemed to enjoy it!

all in all a massive success and i'm not changing back!

It's still a tad light, so Mr Speedy is making some copper center weights and a copper battery strap for me, to see how this effects the car, more on this as i get it.
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Old 01-11-2011
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Took it out for its second test night last tues,

running 40g of extra weight, 20 under the rear drive shaft, and a 20g copper battery strap, bringing the weight to just above 800g

also switched to an ezrun 35amp speedo to see if the smoother throttle curve would be better.

( Both from Phat Bodies - Phat Weights are the future!)

grip level was awful but the car still felt as good as i remembered it, smooth and easy to drive, but with plenty of steering and the ezrun severely reduced the amount of torque steer.

This car really suits my driving style (smooth as possible with little or no braking) and i felt easily able to put together consistent lap times, this gave me the confidence to post the fastest lap time in each heat i ran (somthing i've never done!)

all in all, i'm looking forward to running this in the national series this weekend.
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Old 02-11-2011
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Thumbs up gt14b mid chassis tests

Quote:
Originally Posted by Matisse View Post
Took it out for its second test night last tues,

running 40g of extra weight, 20 under the rear drive shaft, and a 20g copper battery strap, bringing the weight to just above 800g

also switched to an ezrun 35amp speedo to see if the smoother throttle curve would be better.

( Both from Phat Bodies - Phat Weights are the future!)

grip level was awful but the car still felt as good as i remembered it, smooth and easy to drive, but with plenty of steering and the ezrun severely reduced the amount of torque steer.

This car really suits my driving style (smooth as possible with little or no braking) and i felt easily able to put together consistent lap times, this gave me the confidence to post the fastest lap time in each heat i ran (somthing i've never done!)

all in all, i'm looking forward to running this in the national series this weekend.
Looking forward to seeing this new project Mat sounds like you have it locked down mate
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Old 28-11-2011
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Thumbs up Switch hitter!

Mat....I've just got one!! aviiit
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Old 28-11-2011
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sweet!! watch the alignment of the slipper, the prototype chassis was a little out of line leading to some squeeking, careful construction solved this though.

weight wise, si from phat bodies did me a copper battery strap and 30g of centre weights which mad a huge difference.

let me know what you think of it mate.
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Old 28-11-2011
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Great write up by the guys at Off-Road Radio Control


http://offroadradiocontrol.blogspot....r-chassis.html
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Old 31-10-2015
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Default gt14b switchitter

Hi guys sorry for bringing up an ancient thread here but looking for one of these as rcmi appears to no longer be trading and the original designer mattise has not logged in here for a couple of years was wondering if anybody has one knocking around or at the very least a knackered chassis I can use as a template to make my own as I have a sheet of 1.5mm carbon also a quick question with regards to build do you need to put the diffs in the other way round many thanks Craig
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