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Old 10-19-2009, 10:42 PM   #10816
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Hello all,

I finally received my JRXS-R last week and I've been thinking about what I want to do with it.

We have a regional race series here in W. Canada with a class called 'GT' that is essentially a silver-can touring class. Since there are also folks running Direct Drive cars (such as F103GT) there is no weight limit and open rubber tires. My thinking is that a JRXS-R built as light as possible with nice sticky rubber would do really well in this class .

I wanted to poll the experts on this thread about:

a) Are there any flaws in my logic that you can see
b) How light do you think I could get my car with a small brushed ESC and lipo
c) What direction would you go for setup (I'm thinking a standard rubber/carpet setup with softer springs/lighter damping)

Any ideas you could provide me would be greatly appreciated!

Cheers,
Mike
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Old 10-20-2009, 01:00 AM   #10817
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So, you going to build it? That diff would be awesome.

Up north here we're running a 1500g weight limit so I picked up a steel tray to bring the car up to weight with out resorting to a brick of lead. The thing about the steel tray I noticed is that it makes the chassis absurdly rigid. Have any of you guys found a solution to this problem? Even bolting in the regular plastic tray adds a lot of rigidity. I've got a few ideas that would let the chassis flex independent of the battery tray, but have yet to really lay them out in detail.

Also, does anybody make a different upper deck that gives more room for batteries with vertical exit wires? My SMC 4500s are an awfully tight squeeze even with a modded upper deck.
The answer is yes to all your questions.

I'll test the chassis drawing on my waterjet machine, as soon the drawing prove to be error free it will be machined out of carbon fiber.

Same for the diff. I'll have it machined quite soon, unless Pablo show some interest.

Upper deck is also in the plan. I use lipo with standard corally holes and carbon is too close to my personal taste.

Better will be if you can picture your issue, so I might take it in account while play with solidedge.

About the rigidity added... I've an idea to work on...

Seem that my next season will be on G-Losi.... after a bunch of G-Xray
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Old 10-20-2009, 04:16 AM   #10818
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I like that top deck work, Looks nice! Your racing on asphalt right, any ideas about how this would work on carpet?
I don't know how it would work on carpet as usually flex is slower. My idea is to have flex around center but to "lock up" quick so you still have response and high speed steering. I did some more cutting today and every cut only slightly increased the movement making the chassis better but without any negatives. I'll post some pics tomorrow when I neaten it up.

As for the diff.. I believe pablo is working on it to improve how it works along with keeping the dust out. Anyway see what comes of it. The pictures on the previous page look very nice with bearings but still have the dirt problem.
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Old 10-20-2009, 05:32 AM   #10819
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I like that top deck work, Looks nice! Your racing on asphalt right, any ideas about how this would work on carpet?
I dont see any need for it on carpet...Too much traction sometimes
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Old 10-20-2009, 05:57 AM   #10820
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Same for the diff. I'll have it machined quite soon, unless Pablo show some interest.
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As for the diff.. I believe pablo is working on it to improve how it works along with keeping the dust out. Anyway see what comes of it. The pictures on the previous page look very nice with bearings but still have the dirt problem.
The cat is out of the bag. I have been testing a new diff recently. The diff on the losi is one of the main features of the car. Without the "inside out" diff the design of the car would not even be possible.

The problems I see with the standard diff is the amount of dirt that get into it on asphalt tracks and the way the diff ring slips on only one half of the diff. There should be no doubt that under power the left side( D ring) gets more drive than the right side(brass shim). We have tried the "D ring" mod and all it does is grind away at the inside of the pully. I am very close to a good solution.

I am also testing some parts that are used on the inside of the diff tube that give a great tuning option on high grip surfaces. Can't say any more on that at the moment.

After breaking a couple of outdrives on the Flying Fox spool I will also soon release machined Delrin Outdrives. Looking at the broken Losi outdrives, I was very dissapointed with the material Losi used. Quite soft and brittle. The Flying Fox outdrives will be a massive improvement as Delrin is strong and has low frictional properties. They will last longer and allow your suspension to work smoother on power.

Please note that Losi outdrives should only break on quite high traction surfaces with a setup that doesn't unload the inside front tyre in a turn.

Giorgio I think it is great to see someone else looking to keep improving what is already an awsome car. Keep it up. I like the idea of an 18 ball diff. Are you planning on making machined pullies? That would be cool. If you want to talk to me maybe we can put our ideas together and make the best diif on the planet!

Will keep you posted.
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Old 10-20-2009, 06:54 AM   #10821
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Originally Posted by Giorgio View Post
The answer is yes to all your questions.

I'll test the chassis drawing on my waterjet machine, as soon the drawing prove to be error free it will be machined out of carbon fiber.

Same for the diff. I'll have it machined quite soon, unless Pablo show some interest.

Upper deck is also in the plan. I use lipo with standard corally holes and carbon is too close to my personal taste.

Better will be if you can picture your issue, so I might take it in account while play with solidedge.

About the rigidity added... I've an idea to work on...

Seem that my next season will be on G-Losi.... after a bunch of G-Xray
Quote:
Originally Posted by Pablo Diablo View Post
The cat is out of the bag. I have been testing a new diff recently. The diff on the losi is one of the main features of the car. Without the "inside out" diff the design of the car would not even be possible.

The problems I see with the standard diff is the amount of dirt that get into it on asphalt tracks and the way the diff ring slips on only one half of the diff. There should be no doubt that under power the left side( D ring) gets more drive than the right side(brass shim). We have tried the "D ring" mod and all it does is grind away at the inside of the pully. I am very close to a good solution.

I am also testing some parts that are used on the inside of the diff tube that give a great tuning option on high grip surfaces. Can't say any more on that at the moment.

After breaking a couple of outdrives on the Flying Fox spool I will also soon release machined Delrin Outdrives. Looking at the broken Losi outdrives, I was very dissapointed with the material Losi used. Quite soft and brittle. The Flying Fox outdrives will be a massive improvement as Delrin is strong and has low frictional properties. They will last longer and allow your suspension to work smoother on power.

Please note that Losi outdrives should only break on quite high traction surfaces with a setup that doesn't unload the inside front tyre in a turn.

Giorgio I think it is great to see someone else looking to keep improving what is already an awsome car. Keep it up. I like the idea of an 18 ball diff. Are you planning on making machined pullies? That would be cool. If you want to talk to me maybe we can put our ideas together and make the best diif on the planet!

Will keep you posted.
WOW it s all sounds great!! awesome news!

I especialy love to see the diff and the Derlin out drives,

you guys trying to make the already best TC , better. can it be done?
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Old 10-20-2009, 07:08 AM   #10822
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Originally Posted by da_John_wee View Post
WOW it s all sounds great!! awesome news!

I especialy love to see the diff and the Derlin out drives,

you guys trying to make the already best TC , better. can it be done?
You have no idea! The hidden potential this chassis has is unreal.
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Old 10-20-2009, 07:19 AM   #10823
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With regards to the flex upper deck on Carpet I tested that at the weekend on a VERY high traction carpet surface. With the flex deck car felt ok, it wasn't in danger of rolling but did not feel as quick through the bends. I popped the normal deck on and went .5 second a lap quicker.

Another idea for you Pablo... How about some sort of low profile heatsink that can clip to the motor and fit snugly between the bulkheads? That would be cool
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Old 10-20-2009, 07:41 AM   #10824
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Originally Posted by Hyper_Mike View Post
Hello all,

I finally received my JRXS-R last week and I've been thinking about what I want to do with it.

We have a regional race series here in W. Canada with a class called 'GT' that is essentially a silver-can touring class. Since there are also folks running Direct Drive cars (such as F103GT) there is no weight limit and open rubber tires. My thinking is that a JRXS-R built as light as possible with nice sticky rubber would do really well in this class .

I wanted to poll the experts on this thread about:

a) Are there any flaws in my logic that you can see
b) How light do you think I could get my car with a small brushed ESC and lipo
c) What direction would you go for setup (I'm thinking a standard rubber/carpet setup with softer springs/lighter damping)

Any ideas you could provide me would be greatly appreciated!

Cheers,
Mike
I am pretty sure I read that the boss on silver can motors doesn't fit through the hole in the type-r motor mount. You can dremel it as there is plenty of metal, just something you may want to do ahead of time.

I imagine you can get under 1400g with a small brushed setup and a lower mah lipo. Lighter isn't always better though, more weight can provide more overall grip.
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Old 10-20-2009, 08:06 AM   #10825
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Originally Posted by JRXS_chris View Post
With regards to the flex upper deck on Carpet I tested that at the weekend on a VERY high traction carpet surface. With the flex deck car felt ok, it wasn't in danger of rolling but did not feel as quick through the bends. I popped the normal deck on and went .5 second a lap quicker.

Another idea for you Pablo... How about some sort of low profile heatsink that can clip to the motor and fit snugly between the bulkheads? That would be cool
Now that would be a kewl idea although mayb a heatsing that bolts directly to the bulkheads where the 25mm fans go might be easier. What ever the case a heatsink that uses the area infront of and behind the motor with minimal height would work well with the layout of this chassis. Many heatsinks currently have very small fins except the lrp which chocks the vents on modern brushles motors.
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Old 10-20-2009, 08:18 AM   #10826
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Now that would be a kewl idea although mayb a heatsing that bolts directly to the bulkheads where the 25mm fans go might be easier. What ever the case a heatsink that uses the area infront of and behind the motor with minimal height would work well with the layout of this chassis. Many heatsinks currently have very small fins except the lrp which chocks the vents on modern brushles motors.
if you are going to maek a heat sink this is what I was going to make last year but never did since I'm not in this Bz nomore.

I named "one sink" all you need to make is one piece LOSA4329 and 4330 with pins on middle with your logo engraved.

I found you can make this for lots of popular cars.

if you ever do sell this items get me some cut!
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Old 10-20-2009, 10:05 AM   #10827
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Another idea:



Hope the pic explains it but basically the ackerman link has the 'top hats' ready machined in. The steering arms are machined units to allow for the larger ackerman link.

This will allow a larger area to thread the screws into and reduce the chance of dnf's through losing the screws or binding steering. Also there's the possibility to get some bearings in there too for super smooooth steering.
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Old 10-20-2009, 10:25 AM   #10828
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I don't think I have ever had any problem with the steering assembly but that said it is weight up high so I would prefer to keep it simple and light. I'm giving thought to the direct link setup for this reason.
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Old 10-20-2009, 11:04 AM   #10829
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Originally Posted by JRXS_chris View Post
Another idea:



Hope the pic explains it but basically the ackerman link has the 'top hats' ready machined in. The steering arms are machined units to allow for the larger ackerman link.

This will allow a larger area to thread the screws into and reduce the chance of dnf's through losing the screws or binding steering. Also there's the possibility to get some bearings in there too for super smooooth steering.
Loctite or a tiny dab of CA will solve your issues.
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Old 10-20-2009, 11:13 AM   #10830
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Originally Posted by JRXS_chris View Post
Another idea:



Hope the pic explains it but basically the ackerman link has the 'top hats' ready machined in. The steering arms are machined units to allow for the larger ackerman link.

This will allow a larger area to thread the screws into and reduce the chance of dnf's through losing the screws or binding steering. Also there's the possibility to get some bearings in there too for super smooooth steering.

I like that add BBs idea
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