1441 replies to this topic

[flea]

Maybe I am missing something here, but why can't I use steel for my pans and front nose instead of brass (i.e. K&S stainless 1" wide strips)? We're allowed to use a steel guide tongue, why not use steel anywhere else? The stuff is commercially available, is great looking, solders well, and holds up to some nasty driving habits.

Seems to me that if you can cut it and solder it, then it is scratchbuilding.

Just trying to make sense of it...

[Noose]

Phil, this is addressed in the IRRA Q&A Section. As a reference here is one that discusses a question on the use of steel.

Q: I didn't see bronze, silicone bronze, steel gas welding rod, or stainless steel gas welding rod listed as a frame building material. Are these materials to be considered as not legal?

A: For the purposes of chassis construction material, all bronze rod is considered to be brass rod and thus is allowed. Any type of steel rod is allowed. Please note that "spring steel" sheet is specifically prohibited.

(posted by Greg Wells for the IRRA board)

None of the Retro or D3 classes allow the use of steel for pans or center sections. The main reason is that the class was set up to be reflective of of the chassis that were built in the '60s. I believe that the various Retro/D3 groups determined that steel for pans and center sections was not used until the '70s.

[Ron Hershman]

Maybe I am missing something here, but why can't I use steel for my pans and front nose instead of brass (i.e. K&S stainless 1" wide strips)? We're allowed to use a steel guide tongue, why not use steel anywhere else? The stuff is commercially available, is great looking, solders well, and holds up to some nasty driving habits.

While I understand your feelings regarding using "stainless steel" pans... the rules simply and clearly state... "Chassis Materials: Brass: sheet, rod, and tube; steel: wire, pin tubing, and commercial guide tongues are allowed"

I guess if you made a one-piece (not soldered together) "guide/front nose" from stainless steel, that would be allowed.

[Phil Smith]

I've seen a few five-sided motor brackets lately. Are they legal?

[MSwiss]

Yes. From the IRRA rules:

"Each car must have a brass rear bracket consisting of at least three sides (vertical or horizontal), with each connected side having a minimum width or height of at least .200". Under this restriction, a cut-off brass Womp piece would be allowed."

[slotbaker]

Can the three-sided motor bracket be made up from three pieces (soft) soldered together, or must it be one single piece bent/formed to make a three-sided piece?


Maybe if it was brazed or (hard) silver soldered together, it could be considered as a single piece??

[Cheater]

Steve,

This has been answered before, I think.

Constructing a bracket from three separate pieces is allowed. The pieces must be at least .200" across the narrowest (non-thickness) dimension.

At least that's how I understand it.

[slotbaker]

Oh, OK, I must have missed it.

Seems like a grey area, as the three pieces could be assembled during the frame construction.

But, if it's been discussed before and approved, then that's the end of that. Good.

[Phil Smith]

Yes. From the IRRA rules:

"Each car must have a brass rear bracket consisting of at least three sides (vertical or horizontal), with each connected side having a minimum width or height of at least .200". Under this restriction, a cut-off brass Womp piece would be allowed."

Thanks! I was hoping that would be the answer.

[Bob Campbell]

I am still not clear if the bracket needs to be single piece or if it can be built from three pieces and soldered together. The above paragraph from the IRRA rules does not state this.

I come from a 1/1 car racing backgroud and believe that if the rules do not specificaly say no, then it is legal. The exception to this is when the rule book has a rule that states if it doesn't say that it is legal, then it is illegal. The stupid SCCA rule book has a rule like this.

[Larry Mattingly]

Bob

I agree with your view on rule books...

I have always felt that the 'it's illegal if it's not in the rule book' clause is dumb...

LM

[Noose]

It can be made from three pieces.

[Mike Patterson]

I guess if you made a one-piece (not soldered together) "guide/front nose" from stainless steel, that would be allowed.

I was wondering if homemade steel guide tongues would be legal. I have some steel chassis cut-outs from some JK Eurosport chassis kits that would would work well. I'm just looking for something a little longer than the Slick 7 piece.

Mike Patterson

[Ron Hershman]

Have fun drilling the guide hole, Mike. A longer guide tongue would have more solder surface area, for a stronger joint, over the shorter-length ones.

[Prof. Fate]

Hi,

It is easier and cheaper to push around rules in slots than the real world. Boemker does a couple things I used to do a lot in SCCA.

And I could tell tales about...

Never mind. In slots, Mike has a rep for coming up with killer applications in slots when the rules do not have the "if it isn't mentioned, it is illegal" rule.

Our favorite sort of conversation is the times we had mobs with pitchforks and torches climbing the stairs when we did...

Fate

[Phil Smith]

Personally, I think the IRRA rules are pretty darn good. They allow some leeway, but not too much. They also don't change them all the time like D3 does, which I don't think is good at all.

So while I respect everyone's right to voice their opinion about IRRA rules, I'm glad that the complaints rarely prompt a rule change.

On another note. This is from another thread. I'd thought I'd get an official ruling:

Regarding the use of Mylar tape on a chassis, my view is that such tape is not load-bearing and thus is not actually a part of the chassis.

Greg,

So if I built a chassis exactly like Tony's, but I cut the pans out in the aero areas, and replaced those sections with aero-shaped Lexan pieces, that would be legal?

Or say I replaced the entire aero pan in Tony's chassis with Lexan, would that also be legal?

Or enclosed the entire bottom of the car with Lexan, is that legal?

I'm not trying stir up anything. I just want to know in advance before building something like that.

[Rick]

I was wondering if homemade steel guide tongues would be legal. I have some steel chassis cutouts from some JK Eurosport chassis kits that would would work well. I'm just looking for something a little longer than the Slick 7 piece.

Mike, use one of these, nothing to knock off, trim to desired length. LOL.

[Rick]

Phil,

Do you really feel that the aero wings do anything? Do you think that the car would be worse with flat pans?

Cover the entire bottom with a sheet of Mylar/Lexan, you may be quite surprised at the results...

[idare2bdul]

Mike, I'm pretty sure the answer is "Yes", at least I hope it is yes because that is what I did and I helped make the rules for the IRRA. But it must be done by an approved rebuilder and have a seal on it.

The motor with the Chinese arm comes with an endbell slightly too small for the American arm commutator. Pro Slot does offer a replacement endbell at a low price to convert it. I'm sure your rebuilder can easily either relieve the endbell or replace it with the upgrade. Replacing the can bushing is also a good idea to do at the same time you have your motor apart.

[Cheater]

So if I built a chassis exactly like Tony's, but I cut the pans out in the aero areas, and replaced those sections with aero-shaped Lexan pieces, that would be legal?

Or say I replaced the entire aero pan in Tony's chassis with Lexan, would that also be legal?

Or enclosed the entire bottom of the car with Lexan, is that legal?

Phil,

The short answer is that Lexan is not on the list of materials approved for chassis construction.

As mentioned earlier, using Lexan or Mylar to close off holes in the chassis would IMO be fine.

I would opine that constructing side pans from .040 Lexan sheet would not be allowed, as in this example the plastic is being used for load-bearing parts of the chassis itself.

From my perspective, if the plastic was an addition to a complete functional chassis, then it should be OK in most cases, though it's hard to be certain without looking at the specific chassis under question.

[Phil Smith]

Do you really feel that the aero wings do anything? Do you think that the car would be worse with flat pans?

Cover the entire bottom with a sheet of Mylar/Lexan, you may be quite surprised at the results...

Rick,

If you're referring to TonyP's car, I'm inclined to think the wings do indeed work. Closing up the entire bottom should make them work even better I would think. I'm wondering if that would make the motor run hotter though.

[Phil Smith]

Greg,

Covering a small area, or the entire bottom of the chassis with Lexan, is one and the same. In either instance, all you would be doing is covering hole(s) in the chassis. It's flimsy Lexan. It's not contributing any structural strength. Chassis strength and flex would remain unchanged.

There's no reason this should be a gray area decision (which are lame and suck!). Quit being a wimp and make a defined ruling.

[Cheater]

Phil,

The official IRRA rules interpretations are made by the entire board, which is why my reply to you is in this thread instead of the IRRA Rule Questions & Answers thread.

Wasn't trying to waffle and I tried to indicate that any non-structural use of plastic on a chassis should be fine.

However, your question is somewhat hypothetical and it's hard to give unequivocal answers to "what ifs..." as opposed to "what have we heres..."

[Phil Smith]

Greg,

So will there be an answer in the IRRA Rule Questions & Answers froum?

I don't really care which way you guys rule. I'd just like to know what my options are.

[Cheater]

Phil,

Yep, we can do that, but I gotta warn you it may not happen today. I'll be in SC all day tomorrow for our SERRA race and I have so much to do before I can leave, I probably won't even turn on the computer at home tonight.