Author Topic: Tubing requirement change for 2-wheel streamliners  (Read 78440 times)

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Offline Tman

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #75 on: November 18, 2012, 10:46:25 AM »
Welcome Larry!

Trent
« Last Edit: November 18, 2012, 02:07:56 PM by Tman »

Offline Peter Jack

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #76 on: November 18, 2012, 11:44:51 AM »
Hi Larry. I went into your web site and really enjoyed the tour. That's a really interesting looking bike. I really liked your slightly different approach. Good luck with the rest of the build and we'll look forward to your appearance on the salt.  :cheers: :cheers: :cheers:

I'm one year ahead of you and probably a few senior moments ahead of you. They're frustrating but we still seem to be able to work around them most of the time. I think we've always had some of them and we just called it absent mindedness!

Pete

Offline Dean Los Angeles

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #77 on: November 18, 2012, 12:54:22 PM »
If you watch the videos of Indy car crashes in the 60's there was no frame deformity, but the driver died anyway. The frames were so strong that all of the crash forces were transferred to the driver.

Highway crashes were the same thing. The crash forces were transferred to the driver.

In both cases deformable structures and decelerable padding or air bags were designed to allow the forces of deceleration to be transferred away from the driver.

Making the streamliner frame is the same challenge. I can't help but laugh when I picture the Buddfab 50cc liner with an 1 5/8 frame.

Both Indycar and NTSA have money to study the situation. Indycar designs have to be crash tested and all of the cars have G force data recorders.

Kent is mostly correct about his description of the crash attitudes for streamliners. At least we don't have walls to hit. The angle of hardest impact can't be determined, so you have to design for any angle of impact. I think SCTA has done a reasonable job in recommending roll cage and safety requirements.

I don't know how these were determined. I suspect that other forms of racing were used as a model. I really doubt SCTA spent any money in engineering studies. Correct me if I am wrong.

The person responsible for the safety of the driver is the person that designs the streamliner. Finite Element Analysis (FEA) of the strength of the structure and crash scenario simulations should be computed.
The result is not only the strength calculations of the frame, but the G force loading on the driver.

Ok, raise your hand if you have that kind of money.

Looking at the VERY suspect frames that have shown up over the years with crappy welding and you name it, it is very responsible that SCTA has made the rules that they have.

I'm very much with Kent and others in my disrespect for rule making that has gone on in the SCTA. Mike Manghelli has made statements to me that were, well, unbelievable.

You still have to work within the system if you want to run SCTA events. Keep it in mind that no one is getting a paycheck, and the spectator dollars are zero. Everything we do, we get to pay for it.

This rule was not in the best interests of the safety of the vehicle. Engineering opinions have been posted on this thread that make it clear to the non-engineer that a 60's Indycar frame would be the result.

Ok, so what is the best path to recommend here? Low buck, possibly dangerous, self designed vehicles? High buck engineered solutions that rule out 99% of us? Or SCTA trying to find a solution that will cover every situation through rule making.

Well, it used to be Los Angeles . . . 50 miles north of Fresno now.
Just remember . . . It isn't life or death.
It's bigger than life or death! It's RACING.

Offline Heliophile

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #78 on: November 18, 2012, 07:45:09 PM »
Agghhhhh, I hit some button and lost my message.  My fingers on the keyboard are like untrained rats.  Is there an undo button?

Land speed racing is still amateur and resonable affordable.  I would llike to see it stay that way, as no doubt all of us would.  The folks who make it possible spend a ton of their time and resources to make it possible, and certainly deserve our thanks and respect.  Rule making in particular is not easy.  That said, it must be responsible, which we can work toward if we pool our experience and knowledge.

I am under the impression that drag racing roll cage requirements are in stages, according to elapsed time allowed or something such.  I was going to look into it.  Amybody know already?

Offline Jon

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #79 on: November 18, 2012, 10:32:22 PM »
Please resist the urge to make this complex.
If the cage doesn't deform the g force transmitted to the rider is all but exactly the same regardless of the tubing size.

The cage and harness needs to keep us inside the cage, the cage needs to keep other bits out.

Can't be much more complex than that.

jon
Underhouse Engineering
Luck = Opportunity + Preparation^3

Offline Plmkrze

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #80 on: November 19, 2012, 07:28:35 AM »
Please resist the urge to make this complex.
If the cage doesn't deform the g force transmitted to the rider is all but exactly the same regardless of the tubing size.

The cage and harness needs to keep us inside the cage, the cage needs to keep other bits out.

Can't be much more complex than that.

jon

BINGO!  We have a winner.

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Offline Tman

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #81 on: November 19, 2012, 09:52:52 AM »
Please resist the urge to make this complex.
If the cage doesn't deform the g force transmitted to the rider is all but exactly the same regardless of the tubing size.

The cage and harness needs to keep us inside the cage, the cage needs to keep other bits out.

Can't be much more complex than that.

jon

BINGO!  We have a winner.

B.S. in Physics!
which means you make the coffee when around PHD's!!!

Only because the PHds have a hard time tying their shoes in the morning, let alone making something as complex as coffee! :-D

Offline wobblywalrus

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #82 on: November 19, 2012, 11:13:44 PM »
A comment from the engineering community.  An engineer can certify something was subjected to a test, the test was done according to guidelines, and the sample passed or failed.   Example, any of the American Society of Testing and Materials tests.  The engineer can attest that something was designed using an established procedure.  Example, the American Association of Transportation Officials Load Factor bridge design method.  It is hard for a engineer to say something is "safe."  This is too subjective.

Usually we start a job like this with a literature search.  First we look for examples of how other organizations deal with the exact same problem.  Then, we look at how others deal with similar issues, such as the aviation community.  This is just the beginning.

A set of draft guidelines is worked up and representatives of the affected folks like racers, engineers, regulators, legal types insurance people, are all are on the committee.  The draft is hammered on until enough people are happy then it is adopted.

The designer and builder uses these guidelines and the engineer certifies it was done.  Te engineer is certifying that "accepted industry practice" or "state of the art" guidelines were used if anything goes wrong.  This does not absolve the engineer from liability due to poor judgement or incompetence.  It does provide enough protection for the engineer to practice and be covered by insurance.

In this rule making process this should be considered.   The system of a few goofy rules and a bunch of amateur builders does not seem too bad when compared to the demands of professional involvement.       

Offline Steve Walters

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #83 on: November 20, 2012, 12:16:46 PM »
This seems to be a good place to add this experiance into this thread, It has been a good thread, and I am glad the law of commen sense has prevailled, thanks to Tom & Kent.

Years ago I was attending an NFPA class on 70-E, electrical safety.  The room had about 100 students in it, and about 30 of them were engineers.  Two or three of them could not keep there knowledge to themselves, disrupting the class and frustating the instructor.  When we all came back from lunch, with out any guidance or directions the engineers ended up on one side of the room, and the rest of us on the other.  The instructor was able to focus on the side of the room without the engineers, and it was a good learning experiance.   :-)

Steve   
I've been from Bone to Blackfoot, but still just a Newbie here.

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Offline jimmy six

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #84 on: November 20, 2012, 12:25:58 PM »
From working with all types of engineers in my 47 years in the bulk power plant industry I have learned one very important thing.

I want 12 of them on my jury. One can't make a decision how could 12....I rest my case......JD
First GMC 6 powered Fuel roadster over 200, with 2 red hats. Pit crew for Patrick Tone's Super Stock #49 Camaro

Offline Peter Jack

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #85 on: November 20, 2012, 02:22:14 PM »
I preface this by saying that I know some really good engineers who are also really good racers, fabricators and mechanics.

On the other hand I would say that the majority of the engineers and designers that I've worked with are just as liable to casually ask me, the weldor, "how would you approach this?" and then the next thing I know my idea becomes theirs.

I tend to say on a fairly regular basis that there are lots of engineers that can design the wrench but there are only a few that can use it!

Pete

Offline Graham in Aus

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #86 on: November 20, 2012, 05:52:40 PM »
This thread is drifting a little, but now the pressure has gone from the roll cage tubing issue I’ll add my bit of thread drift and maybe contribute to the ‘Engineers’ discussion.....

Alec Issigonis the brilliant designer of the Mini and Morris Minor had a hand’s on helper, William ‘Jack’ Daniels. In the 20 or so months following the Suez Crisis and the explosion of sales of ‘bubble cars’ in Europe Issigonis came up with the ideas for the Mini, but Jack made it work!

Jack’s famous quote was “Issigonis provided the inspiration, but I provided the perspiration!”

 :cheers:

Offline Milwaukee Midget

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #87 on: November 20, 2012, 09:58:39 PM »
“Issigonis provided the inspiration, but I provided the perspiration!”


Success has a lot of parents, but it's the midwife who boils the water and slaps the baby on the ass.
"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

Offline Jon

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #88 on: November 20, 2012, 10:11:31 PM »
Didn't mean to start an engineer bashing session, I normally only do that at work sorry.

I'm following the rules.
I'm going to do beaming and torsional tests on my frame.
I'm building using Cremona principles as much as possible.
I'm keeping the span lengths short-ish to get maximum effectiveness of the tubing.
I'm making sure that the front wheel can't come in for a play if it gets upset.
I'm sheeting the whole riders compartment frame for torsional strength, keeping me in and other bits out.

If there was some useful analysis that could be done to I'd interested to know what it is and what the outcome I would be looking for.

Thanks
jon
Underhouse Engineering
Luck = Opportunity + Preparation^3

Offline wobblywalrus

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Re: Tubing requirement change for 2-wheel streamliners
« Reply #89 on: November 20, 2012, 10:15:03 PM »
Jack Daniels helps me, too.