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Flexi chassis with adjustable body mounts


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#1 dalek

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Posted 04 December 2019 - 08:41 AM

I wonder if the following would be appealing to a lot of people.
 
What if a manufacturer sells bodies that have the mounting holes pre-punched.  You paint the body, cut it on the cut lines (even the wheel wells have cut lines) then snap it on the chassis.  You then turn adjustment screws (accessed from underneath) that independently raise and lower the front body mounts until you have the front bumper a couple of thou above the track surface.  The car now has a new body, it's adjusted perfectly in regard to the track surface, and it has taken you very little time to do it.
 
The manufacturer could also sell bodies that are already painted and cut out.  Take the body out of the package, snap it on the chassis, adjust the mounts, and go race.
 
Maybe the JK Cheetah 21 would be a good chassis to come with adjustable body mounts.
 

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#2 Dave Crevie

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Posted 04 December 2019 - 10:07 AM

That would be fine if every chassis had the same mounting holes. Start a one chassis spec series and get someone to punch the holes on a body mounting fixture.



#3 Racer36

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Posted 04 December 2019 - 10:49 AM

Perhaps just buy yourself a decent body mounting fixture and then there is no need to re-invent the wheel.


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#4 scooter_trasher

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Posted 15 December 2019 - 06:12 PM

I want a car body made of super elastic bubble plastic, that bounces off the wall back into my slot :)


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#5 MarkH

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Posted 15 December 2019 - 08:26 PM

Hi Dale, I understand your frustration with trying to get the body mounted exactly the way you want.

 

Please check out post #175 here:

http://slotblog.net/...-fixture/page-7


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#6 dalek

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Posted 15 December 2019 - 09:11 PM

Hi Dale, I understand your frustration with trying to get the body mounted exactly the way you want.

 

Please check out post #175 here:

http://slotblog.net/...-fixture/page-7

 

I already knew about that thread but thanks for the suggestion. 

 

Actually, I made a fixture along the same lines but mine is narrow enough that I don't have to make final cuts until after I've punched the holes.  My narrow fixture allows me take a body that's just been roughed off and slide it forward and back and also up and down, so I can adjust how close the body will be to the guide and motor and how high or low I want the body to be (don't always want it on the cut line, if there even is a cut line).

 

I probably just need to refine my fixture until I get the accuracy that I want.

 

Thanks again.



#7 dalek

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Posted 23 December 2019 - 07:47 AM

Perhaps just buy yourself a decent body mounting fixture and then there is no need to re-invent the wheel.

 

 

Hi Dale, I understand your frustration with trying to get the body mounted exactly the way you want.

 

Please check out post #175 here:

http://slotblog.net/...-fixture/page-7

 

Someone correct me if I'm wrong but I think a problem with using Mark Horne's Lateral-G Slot Sport Body Pro fixture is that it's designed for chassis that have pin tube mounts rather than body clips.  When clips are used, the holes in the body have to be closer to each other by roughly .015".  Even though that might not sound like much, just take a body that mounts properly with pin tubes and put a clip on the body and see how wavy the body becomes between the mounting holes.
 
This problem occurs with my JK chassis and is even more pronounced on my Mossetti chassis because the holes in the body mount tabs are bigger in diameter than JK holes.  In other words, the clips that snap properly into JK chassis have to be shortened a few thou to properly snap into Mossetti chassis.


#8 dalek

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Posted 23 December 2019 - 07:50 AM

In post #1 I said the adjustable body mount screws would be accessed from the bottom of the chassis but after giving it some more thought, it seems to make more sense that they be adjusted from the top through holes in the body so you could see the front bumper clearance changing as you turn the screws.  The holes in the body would only need to be the diameter of the screw driver.  Maybe the adjustment screws could be .050 drive allen screws then the holes in the body would only need to be about 1/16" in diameter.
 
FWIW:  I see that this thread has an unusually high number of hits compared to the number of replies.  I wonder if it's because a lot of people would like to see this feature.
 


#9 jimht

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Posted 23 December 2019 - 09:59 AM

My attitude is that the problem has always been that of using a body mounting system which started with screws and just devolved into more complexity with the "improvements" of tubes/pins and clips.

 

Body positioning would be infinitely more adjustable if chassis were designed to use this stuff instead:

https://www.3m.com/3...294857497&rt=r3

 

And, it allows mounting elsewhere besides the sides...

But, "Que sera, sera", we've been stuck in a time warp since the Sixties. YOMV.  :laugh2:


Jim Honeycutt

 

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#10 MSwiss

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Posted 23 December 2019 - 10:57 AM

It would be great if it worked well, but we've done a bunch of hardbody racing, and it really doesn't.

 

It didn't hold as well you would think.
 

Maybe because of the weight of hard bodies, or that the sides are curved.

 

Guys who tried to use it, always wound up also using tape in the race.

 

And even with a built-in ledge,, like on an FCR, getting fore-aft movement , the same, each time, is a bit tricky.

 

Bottom line, that system doesn't have referencing.


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Mike Swiss
 
Inventor of the Low CG guide flag 4/20/18
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Two-time G7 World Champion (1988, 1990), eight G7 main appearances
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#11 Racer36

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Posted 23 December 2019 - 12:54 PM

Someone correct me if I'm wrong but I think a problem with using Mark Horne's Lateral-G Slot Sport Body Pro fixture is that it's designed for chassis that have pin tube mounts rather than body clips.  When clips are used, the holes in the body have to be closer to each other by roughly .015".  Even though that might not sound like much, just take a body that mounts properly with pin tubes and put a clip on the body and see how wavy the body becomes between the mounting holes.
 
This problem occurs with my JK chassis and is even more pronounced on my Mossetti chassis because the holes in the body mount tabs are bigger in diameter than JK holes.  In other words, the clips that snap properly into JK chassis have to be shortened a few thou to properly snap into Mossetti chassis.


I will gladly correct you Dale. The Lateral G body mounting fixture works equally well for clips or pin tubes. In fact, I think it is a superior way to mount bodies for clips. The slightly larger hole you get lets the body move around just a touch more.

 

Dennis Dominey

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#12 jimht

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Posted 23 December 2019 - 01:44 PM

"It would be great if it worked well, but we've done a bunch of hardbody racing, and it really doesn't."

 

Actually, I didn't say anything about hardbodies.

 

OTOH, works well for me on both hardbody and Lexan rental cars...go figure. Maybe I kept hammering at it until the problems went away... :dash2: 


Jim Honeycutt

 

"I don't think I'm ever more 'aware' than I am right after I hit my thumb with a hammer." - Jack Handey [Deep Thoughts]


#13 MSwiss

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Posted 23 December 2019 - 01:55 PM

Do you think it would hold the body at serious racing speeds?

IOW, something like a Group F?

Mike Swiss
 
Inventor of the Low CG guide flag 4/20/18
IRRA® Components Committee Chairman
Five-time USRA National Champion (two G7, one G27, two G7 Senior)
Two-time G7 World Champion (1988, 1990), eight G7 main appearances
Eight-time G7 King track single lap world record holder

17B West Ogden Ave., Westmont, IL 60559, (708) 203-8003, mikeswiss86@hotmail.com (also my PayPal address)

Note: Send all USPS packages and mail to: 5858 Chase Ave., Downers Grove, IL 60516


#14 jimht

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Posted 23 December 2019 - 03:15 PM

Sticks the body to the car about as well as tape, clips, pins or screws and could be used in conjunction with any of those options, but that's not actually the issue that the thread is concerned with, eh?

 

The OP was looking for an easier way to mount the body correctly on the car. Dual Lock makes positioning the body really easy.  :D 


Jim Honeycutt

 

"I don't think I'm ever more 'aware' than I am right after I hit my thumb with a hammer." - Jack Handey [Deep Thoughts]


#15 MSwiss

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Posted 23 December 2019 - 03:21 PM

I use the Dual Lock, and I just wasn't as excited about it, as I thought I would be.

Can you show a picture of the amount of surface area needed for good locking?

As far as solving his problem now, it's not going to work with an existing legal flexi car, so I guess you're really not helping the OP.

Mike Swiss
 
Inventor of the Low CG guide flag 4/20/18
IRRA® Components Committee Chairman
Five-time USRA National Champion (two G7, one G27, two G7 Senior)
Two-time G7 World Champion (1988, 1990), eight G7 main appearances
Eight-time G7 King track single lap world record holder

17B West Ogden Ave., Westmont, IL 60559, (708) 203-8003, mikeswiss86@hotmail.com (also my PayPal address)

Note: Send all USPS packages and mail to: 5858 Chase Ave., Downers Grove, IL 60516


#16 jimht

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Posted 23 December 2019 - 03:42 PM

http://slotblog.net/...as/#entry751270


Jim Honeycutt

 

"I don't think I'm ever more 'aware' than I am right after I hit my thumb with a hammer." - Jack Handey [Deep Thoughts]


#17 MSwiss

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Posted 23 December 2019 - 03:56 PM

What's the blue foam on the inside, back part of the body, for?

post-43-0-28253200-1559414162.jpg

Mike Swiss
 
Inventor of the Low CG guide flag 4/20/18
IRRA® Components Committee Chairman
Five-time USRA National Champion (two G7, one G27, two G7 Senior)
Two-time G7 World Champion (1988, 1990), eight G7 main appearances
Eight-time G7 King track single lap world record holder

17B West Ogden Ave., Westmont, IL 60559, (708) 203-8003, mikeswiss86@hotmail.com (also my PayPal address)

Note: Send all USPS packages and mail to: 5858 Chase Ave., Downers Grove, IL 60516


#18 Rotorranch

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Posted 23 December 2019 - 04:15 PM

Rear crash structure, sort of like the attenuator on an Indy Car.

 

Or a mobile "soft wall".

 

Rotor


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#19 jimht

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Posted 23 December 2019 - 04:51 PM

"Rear crash structure, sort of like the attenuator on an Indy Car.

 

Or a mobile "soft wall"."   :laugh2: 

 

 

Good one but no: just lightweight support for the rear of the body for ham-handed kids that pound the car back into the slot.


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Jim Honeycutt

 

"I don't think I'm ever more 'aware' than I am right after I hit my thumb with a hammer." - Jack Handey [Deep Thoughts]


#20 MSwiss

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Posted 23 December 2019 - 05:14 PM

If you need that, it's not holding the body on as well as pins or clips.

Even if it didn't need that, say if you had all delicate turn marshal's, or racers who didn't need quick reslotting, the extra weight, high CG, and diminished body flex, would be a non-starter, for performance minded racers.

I whole heartedly agree it's fine for rental cars.

I personally think the OP is posing a non-problem.

Stick on a new piece of bullet proofing, and repoke, if you missed by a lot, on the first effort.

Seems much simpler than adding something to the chassis that would probably increase the price by $10 and require a rule change to allow "holy bodies".
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Mike Swiss
 
Inventor of the Low CG guide flag 4/20/18
IRRA® Components Committee Chairman
Five-time USRA National Champion (two G7, one G27, two G7 Senior)
Two-time G7 World Champion (1988, 1990), eight G7 main appearances
Eight-time G7 King track single lap world record holder

17B West Ogden Ave., Westmont, IL 60559, (708) 203-8003, mikeswiss86@hotmail.com (also my PayPal address)

Note: Send all USPS packages and mail to: 5858 Chase Ave., Downers Grove, IL 60516


#21 jimht

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Posted 23 December 2019 - 06:31 PM

You win, Mike.

The OP hasn't got a clue.


Jim Honeycutt

 

"I don't think I'm ever more 'aware' than I am right after I hit my thumb with a hammer." - Jack Handey [Deep Thoughts]


#22 MSwiss

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Posted 23 December 2019 - 07:06 PM

The OP is actually a very smart guy.

He writes very detailed race reports, has made charts to help with ghost drivers, in round-robins, etc.

But raising the nose, up and down, on a current flexi style chassis, isn't a super-easy design, to come up with.

With the current designs, I don't see how you could do it, without effecting the body movement.

But I'll give it some thought.

I have figured out how not to have your car destroyed, when it gets ridered into the wall, at full speed.

Mike Swiss
 
Inventor of the Low CG guide flag 4/20/18
IRRA® Components Committee Chairman
Five-time USRA National Champion (two G7, one G27, two G7 Senior)
Two-time G7 World Champion (1988, 1990), eight G7 main appearances
Eight-time G7 King track single lap world record holder

17B West Ogden Ave., Westmont, IL 60559, (708) 203-8003, mikeswiss86@hotmail.com (also my PayPal address)

Note: Send all USPS packages and mail to: 5858 Chase Ave., Downers Grove, IL 60516


#23 idare2bdul

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Posted 23 December 2019 - 11:55 PM

You miss the obvious solution which is to have more talented friends mount your bodies. I used to trade motor building and/or painting for body mounting. Those darn toothbrush motors have pretty much killed motor building.


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#24 dalek

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Posted 24 December 2019 - 08:45 AM

Since the tabs on the chassis pans have to stay the same distance apart, any type of adjustment system requires the tabs to be on the same piece of metal.  If you take an existing pan and make about a 6mm long cut just forward of the front body mounting tab then turn and cut all the way back to the rear mounting tab you would then have a single piece of metal, 6mm wide, with both tabs on it, effectively being hinged at the rear, allowing the front to be moved up and down.  However, I don't really want to continue with figuring out the details of how to make an adjustable body mount.
 
What I really want is to refine cutting and mounting bodies in order to get the precision that I prefer, and not requiring an unreasonable amount of time to do it.  So I'm going to search Slotblog for threads that pertain to body mounting and go from there.  Thanks for all of the replies.


#25 Eddie Fleming

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Posted 24 December 2019 - 08:53 AM

 

What I really want is to refine cutting and mounting bodies in order to get the precision that I prefer, and not requiring an unreasonable amount of time to do it.  So I'm going to search Slotblog for threads that pertain to body mounting and go from there.  Thanks for all of the replies.

 

Check Ralph Thorn's body mounting hole punch jig. 

 

Whatever he calls it.

 

Try this link http://ralphthornera...are_c_22-2.html

 

It is called the "body master" and is the last thing on the tools list.


Eddie Fleming





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