Flexible top chassis
 

Hi!

I would like to build a flexible top chassis which bend when rollover, then recover its initial shape after.

for example:
http://img15.hostingpics.net/pics/69...otflexible.png

My question is: can we have the upper part of the chassis that is flexible?
Because windscreen height and total height can change with the flexible shape.

Thank you for answer "thumbsup"

Re: Flexible top chassis
 

I would think that would make it out of spec when rolled over .....

Same principle for when they changed the wheelbase to being measured at full compression. People built trucks to measure 12.5'' at ride ready but when they used their dig it could stretch the truck past 12.5 bringing it out of spec.

Re: Flexible top chassis
 

The real qustion would be what would make the cab go back to original spec height after getting back on your wheels? Can you guarantee that it would go back.

If you cant guarantee it than any time you get back on your wheels youd have to stop time spec check your car. If it doesnt meet spec. You could get a DNF, or if the judge is nice you take a touch and repair it under time until it meets spec.

Re: Flexible top chassis
 

the roof is at limits of rules, of course, and it bends when pressure is applied.
After that, it takes his original shape. Delrin keeps shape :)

Re: Flexible top chassis
 

Would it still meet the 3'' overall height part of the rule even when pressure is applied?


Interpreting this rule I think would make it illegal -

Re: Flexible top chassis
 

http://img15.hostingpics.net/pics/69...otflexible.png

Imo, if the only part of cab was flexible was the top arch, making sure the front top of cab cross brace and windshield area is rigid and never came out of vehicle specs. It would be legal.

To be edited with usrcca rules..
I belive there's a 1" height requirement on the cab

▪ 2.1.4 - The vehicle's roof must be raised a minimum of 1” from the main chassis to resemble a cockpit. The frame sides must be an overall minimum of 1” tall (The cockpit & frame side are to be measured vertically from where the hood intersects the cab).

.▪ 2.1.7 - Vehicles body/ bodiless measurements must reach a minimum of (A) width, (B) length, and (C) height. Measurements may include, but not limited to bumpers, stingers, frame-rails, side-rails, skid plates, roof, hood, and side panels.See Illustration B.

http://i131.photobucket.com/albums/p...psqfmjzzhc.png

A. 3" B. 8" c. 3"

Insure you meet these 2 vehicle specs at all times and you'll be fine.
IMO..

This is the rule that makes me unsure..
3.10 - Changing Vehicle Specs (On Course): The vehicle must run a course entirely with the same wheelbase, track width, ride height, and tires it started that course with. Any changes to the vehicle (other than winching down the suspension or forced articulation) by the driver, another person, or any device, while on the course are prohibited.

with the cab being able to be 1" high minimum, running a flexible cab that could come out of vehicle specs or bust. In return you'll receive dnf on said course, I don't see how a flexible cab is a benefit.

Re: Flexible top chassis
 

Any material can flex with enough pressure. Therefore, my interpretation of the rules is that as long as it meets requirements under a tech inspection, then it's legal. However, if it does not return to spec, the judge is within his rights to stop time and measure the vehicle. If it's out of spec, you're done and you forfeit the course. You decide if it's worth the risk.

Re: Flexible top chassis
 

Still leaves a grey area to exploit ..... I as a judge would call it. ;-)

Re: Flexible top chassis
 

Honestly, as a judge, I'd probably tech it after every course. Delrin only returns to its original shape so many times before it breaks.

Re: Flexible top chassis
 

Looks like its legal to me?

The wording is weird at the end and I can read it both ways that says you need to replace your body on course or it does not matter.

Re: Flexible top chassis
 

Looks fairly straight forward to me. In this case, if the body breaks or is out of spec, then it needs to be attended to immediately and normal repair penalties apply.

Re: Flexible top chassis
 

As a judge.... and i had to tech this every time you had to roll over. I would be very very strict on the measurements out of purely being annoyed.

Re: Flexible top chassis
 

hi,
i use this kind of top cab since three years now on my Ventru chassi.

my idea is just to make it flexible enought to flex and not break on a big crash.

so if you push hard on it he go down and go back up.
but on roll over there is no effect on it, it stay in the frame.

http://img11.hostingpics.net/pics/20...1206105945.jpg

Re: Flexible top chassis
 

▪ 1.4.4 - Vehicle Out of Spec: If the Judge has reason to believe a vehicle is out of spec during a course run, he may call time to stop. At that point no additional inputs may be given by the driver to the vehicle via touch or radio control. The Judge must mark the vehicle’s location and perform a tech inspection in the specified tech area (same manner as all other tech inspections). If the vehicle has been deemed within spec, the driver and vehicle will return to the location marked by the judge and the clock will start once again.



Regardless of whether the vehicle is on it's wheels or on it's roof, it must remain within spec. As soon as a flexible top is flipped and compressed, it is out of spec which triggers the option for the judge to call time, mark the location and perform an inspection in the tech area.

Basically if the judge wanted to be an ass (and having to deal with a vehicle that was constantly going out of spec, I wouldn't blame them) they could call time whenever the vehicle is on it's roof. This would negate any attempts of trying to recover on your own.

I would think this alone would make a flexible top a no-go, but I'm not a rules person. If I was, I'd vote that any feature that knowingly puts your vehicle out of spec while on course should be illegal.

Re: Flexible top chassis
 

The problem is: when the car is in the tech-area,everything is OK (the flexible top is in it´s normal position). But when the car is on it´s roof,it is out of spec. My thoughts are: the car should always be in correct spec,not only in the tech-area. But it´s a question how to read the rules....

Re: Flexible top chassis
 

• 3.10 - Changing Vehicle Specs (On Course): The vehicle must run a course entirely with the same wheelbase, track width, ride height, and tires it started that course with. Any changes to the vehicle (other than winching down the suspension or forced articulation) by the driver, another person, or any device, while on the course are prohibited.

▪ 1.4.4 - Vehicle Out of Spec: If the Judge has reason to believe a vehicle is out of spec during a course run, he may call time to stop. At that point no additional inputs may be given by the driver to the vehicle via touch or radio control. The Judge must mark the vehicle’s location and perform a tech inspection in the specified tech area (same manner as all other tech inspections). If the vehicle has been deemed within spec, the driver and vehicle will return to the location marked by the judge and the clock will start once again. If the vehicle is now out of spec and the Judge has determined that the vehicle has gained an advantage, the driver must take a repair (see rule 1.4.3) to correct the problem. If the problem can not be corrected to bring the vehicle back within spec, the driver will receive a DNF for that course (see rule 1.8 ). If a vehicle falls out of spec due to breakage on course and the Judge determines the driver has not gained an advantage, then the driver may be allowed to continue on course without stopping time and requiring a tech inspection. Bodies, and body panels are not included in this exception, and must be replaced immediately, standard repair procedures and penalties apply.


Would you make a driver put his body back on if it fell off his 2.2S truck or would you let him continue the course?

I would call it the truck is its own device - when upside down caused it to fall out of spec and the driver can gain an advantage.


1.2 Back

Up/ Reverse: (1 pt)

Point is given when a vehicle reverses course after making forward progress.

Reversing is defined as any of the tires moving in the reverse direction, whether engaged or in freewheel

and/or whether intentional or not. Once a reverse penalty is given, no further reverse penalty can be given until

the vehicle makes forward progress. No penalty is given if the backward movement occurs while the vehicle is

in the rollover position. (See Sec. 6 Rollover Position) If a driver begins a course in reverse, a reverse penalty

will occur immediately. (See Reverse examples and explanations Sec. 7)

Re: Flexible top chassis
 

I agree with you. That's why I included the last sentence about "knowingly" going out of spec on course. If you know your vehicle will go out of spec, then you should take the necessary precautions to prevent it.

"thumbsup"


And these are just my opinions. I know a lot of people love to look for loopholes in the rules, and this is a good one. Hopefully someone makes a good judgement call on it.

Re: Flexible top chassis
 

so when a lexan body distorts out of spec than pops back into shape...the driver should be penalized?

Re: Flexible top chassis
 

You make a good point Zoso, but the lexan body out of shape doesn't necessarily provide an advantage. If the cap collapes under the weight of the car he can effectively drive it upsidedown, providing (at least perceived) advantage....

Re: Flexible top chassis
 

Valid point Zoso.


What lexan body when mounted could lay virtually flat giving the same advantage?