Tubing requirement change for 2-wheel streamliners

[Freud]

all Cal Tech did was to use Sam's  streamliner as a class project for an aero package and used the wind tunnel.

I'd say that is a huge advantage as compared to most builds......two or four wheelers.

FREUD

[Rex Schimmer]

Ed Weldon said in his post #119 "Rex - You and others are right as far as you go.  But the devil is in the details.
For one thing, by your statement, the transition to 1-5/8 tubing for 2 wheel streamliners would cause no harm other than throwing thousands of hours and dollars of past and ongoing construction effort into the trash heap."

Ed I am sorry if you took my post as a support of the SCTA proposal to change the motorcycle streamliner tubing specs to 1 5/8 tubing. I am in complete agreement with most of the people on this site that the 1 5/8 tube proposal was a knee jerk reaction by the SCTA rules committee and not well founded on engineering or empirical data.

I am some what at a lose as to the thinking that going to an engineering school to have this type of design done by a group of engineering students is a good idea. I spent 4 years getting an engineering degree and 45 years learning to be one. Yes they can do the Solid Works, the FEA and analysis but only if people that have experience in the landracing field can provide them with the parameters that define the problem. Having worked with a number of young engineers I find many of them wanting to "redesign the wheel" on projects when solutions already exist and their lack of experience does not allow them to realize this. Using a university engineering student group to do this work is a great idea but it will require some close overseeing to make sure that they stay on task. I know that Jon Bennett is planning to have Woody do an FEA analysis of his frame design and with Woody's years of practical experience and knowledge this is the type of analysis that I would have real faith in to provide real data that is applicable to Jon's project..


Rex

[Jon]

I'm still drawing my frame up in CAD, I'm very slow on CAD (slow in a lot of other ways too but another story).

I have two problems;
What is the question I'm asking?
My understand of FEA is not great, I understand beaming & torsional tests, also understand they may not be the greatest indicator of the effects of a point impact load.

How does that relate to a bike that isn't identical to mine?

I keep saying don't complicate it and stick by that statement.

IMHO the role of my riders compartment cage along with every other LSR vehicle cage is very simple:
"NOT DEFORM ENOUGH TO LET THE RIDER COME IN CONTACT WITH THE GROUND"

Crumple zones etc can make the job of the cage easier, it is not the job of the cage to crumple though.
Designing crumple into a cage is not an area we should entertain I believe.

Keeping the rider/driver less damaged inside the cage is the role of Helmet, Harness, arm restraints, HANS, roll bar padding, helmet movement distances, good fitting seat (hence my question about pour in seats) etc.

If the cost is reasonable and the outcome useful I will ask Woody to do analysis on my bike and provide the info to all.
I'm still struggling and I believe we all are to fully understand the question.

Facts as I understand them:
Every motorcycle liner has fallen over, most at a decent pace.
There is no documented cases of a rider in a cage that complies with the current rules being injured because the cage deformed.
What is the question again?
jon

[SaltPeter]

That's right Jon, I don't know of any Motorsport that has a collapsible Roll Cage.

The current trend I mentioned was that the Driver Roll Cage/Safety Cell stays intact and there are energy absorbing structures around and within this indestructible compartment.

Meanwhile the fact is this.

We already have safe M/C Streamliners running right now for the Speeds that are being achieved.


Anyone building a M/C Streamliner can learn from them and that's what is and has happened. To me we don't need to change that.

Right now looking at how vehicles are being constructed, is the welding up to scratch, are there enough gussets, is the Cockpit clear etc. needs to be the Priority.

Also providing accessible guidance, when and if needed, during the design and build stage. Providing Tech Inspections before we run at an Event to solve any issues that might need fixing.

This would then at least minimise the chance of a Safety failure if an incident happens. So by the time the any of us are at the Event all Vehicles have had the best chance of doing the Job that they were designed to do.

I would think it's as the Speeds go up we need the research/Data ( and there are many types of research and Data collection) then can incorporate any extra Safety measures into those Vehicle designs. Being ready for the future was probably what is at the heart of the Proposal that started this.

A lot of people simply did not want to throw the Baby out with the Bathwater. And I really believe that would have been the impact of the Tube Proposal.

Pete
One of the Short Men

[edweldon]

.......
Ed I am sorry if you took my post as a support of the SCTA proposal to change the motorcycle streamliner tubing specs to 1 5/8 tubing. I am in complete agreement with most of the people on this site that the 1 5/8 tube proposal was a knee jerk reaction by the SCTA rules committee and not well founded on engineering or empirical data. ...............

 I know that Jon Bennett is planning to have Woody do an FEA analysis of his frame design and with Woody's years of practical experience and knowledge this is the type of analysis that I would have real faith in to provide real data that is applicable to Jon's project..
Rex

Rex-- Sorry I seemed to misunderstand you.  What I meant was that we must look beyond the simple issue of roll cage strength.  My position on this thing is that without the issue of "springiness" of the frame/cage being addressed the technical review of the new cage proposal is incomplete.  My anedotes about hammers, anvils and the Mars Rover don't seem to be connecting. 
So I will put it bluntly to all:  To support a stronger and clearly more rigid frame design (like 2.8 times more so) I will need to be convinced that the elastic flexibility of the 1.25/.095 tube construction is not a significant contributor to the softening of crash impact shocks.  This in the same manner as automotive springs and pneumatic tires reduce shock the effects of roadway irregularities.
To that end I'd suggest Woody, in his FEA analysis make note of the elastic deflections under assumed forces (and directions) of various points in frame as well as the places stresses above yield point of steel.  Hopefully this will provide come insight into the character of "springiness" of the cage.   But short of an ability to determine the effective forces created by ground impacts on an elastically flexible frame the results of an FEA study will be inadequete.
In other words prove to me that 1-5/8/.120 wall tube construction will make the crash shocks worse while making no important improvement in the structural strength of the cage.
BTW, anyone know what CAE software Woody will use?  Cosmos, ANSYS or some other?
Ed Weldon

[edweldon]

The current trend I mentioned was that the Driver Roll Cage/Safety Cell stays intact and there are energy absorbing structures around and within this indestructible compartment.
....................
Meanwhile the fact is this.
We already have safe M/C Streamliners running right now for the Speeds that are being achieved.

Anyone building a M/C Streamliner can learn from them and that's what is and has happened. To me we don't need to change that.
Pete   One of the Short Men

I generally agree with Pete.  Learn how and why something works before you blindly change it.  There is all to much ignorance of this lesson to the dismay we all have with many "new and improved" consumer products.  Sadly, the brownie points seem to go those change artists.  The old fart who counsels "it works fine; tell me why should we change" is quickly forgotten.

I'd like to make one more point.  There is a lot of misunderstanding about how "energy absorbing structures" work both among lay people and engineers.  They slow the application of force to the structure in addition to absorbing energy.  Slower application of force means lower acceleration levels.  That's "G" forces.  That means less "g"s that the cushioning around the driver, helmet, padding, etc. has to stop from reaching the driver's head.
Ed Weldon

[Plmkrze]

Has there been a crash of a M/C streamliner that has deformed the cage/chassis enough to injure its occupant? And this deformation and injury are related to this smaller tubing. As I understand it the answer is no. If the answer is no, then why "align" the M/C streamliners with the Car Streamliners? Leave it alone. If it must be changed, then show us the studies that prove the change is necessary. Do not put it upon the M/C folks to go on the defensive and protect their investments with the studies to prove that the change is not necessary. Do not propose a change based on what is good for geese is good for ducks too!

True, both fly, but ducks are smaller!


BTW, is it just me, or do others see the irony of this thread.  Guys and gals get ON motorcycles and haul ass. With just helmets and leathers! Nobody bats an eye. But, make a M/C streamliner and suddenly folks feel a sense of social responsibility and get worried about your well being. Hypocrisy? Not for me to say, YOU have to make that judgement. 

[Seldom Seen Slim]

Finally - I found it.  On the home page of this site (www.landracing.com) there's a sidebar featuring "EZ Hook News".  I haven't read through it just now - will later - but maybe you'll find more information about Sam's bike than you already knew.  And maybe you'll find out if he did have some form of outside help in designing it. 

I thought I knew that the article(s) was/were in here -- just couldn't remember where they got put.  Thanks, Bob Clancy, for helping me find 'em.

[Glen]

I started keeping a incident list in 1984 per Jim Lattin's request. The following is what type motor cycle was involved.This is at El Mirage & Bonneville
 8. Stream liner Motorcycle  , none had a roll bar/cage failure. There were injuries to some of the riders.

19. Sit on motorcycles 19, all had some type of injury some at over 250 mph. 

1. Side Car  1 rider injuried , towing accident on return road.

NON SCTA/BNI incidents at other venues
 1. Streamliner  Fatal,  Cage & roll bar did not fail
 3. Sit on 3 Fatalities
 1. Side car minor injuries

[55chevr]

That is an interesting data base ... did you save any of the specifics?


Joe

[makr]

Do not put it upon the M/C folks to go on the defensive and protect their investments with the studies to prove that the change is not necessary. Do not propose a change based on what is good for geese is good for ducks too!

Why?

If I was a smart leader I would put it on the guys trying to go fast to prove to me why they think they are safe without me doing a thing. Rule change seems a very effective means to that end...

[edweldon]

If I was a smart leader I would put it on the guys trying to go fast to prove to me why they think they are safe without me doing a thing. Rule change seems a very effective means to that end...

A smart leader will know when his enterprise has a monoploy and when it doesn't.  The difference between the two has a profound effect on how to treat the customers. 
SCTA might have started as a club but it is now a business.  And it has competition.
Note that it provided fine service to several thousand paying customers at Speedweek.
Ed Weldon

[Steve Walters]

The SCTA is a busness,  .  B..ll S..t, There might be a few people that think that way, but all of the Land Speed Associations are venues for Hot Rodders and Gear Heads. 

They started out as a means to enjoy their sport, and evolved into what they are today, and they are not a busness, and they are not in competion with each other.  Most of the volunteers work at all the events, and a lot of the racers run at all of the events. 

A few bad eggs, within the Associations  might think that they are in competition with each other, but that is true with every group that exsists.

The only thing in commen to a busness, is the Venues need racers to survive, and the racers need the Associations. If it was a busness then they would surely think at the board meetings lets shut down, El Mirage, and the finals.  Instead of how can we get more racers to run at these events. 

MHO.
Steve           

[Steve Walters]

Gee's !, I'm sorry Ed, when you get old and retired, ya feel like your not contributing any more and then you get oppinionated.  Your busness quote kind of struck a hard spot in me, cause thats a problem we are having right now, there is a few bad eggs out there trying to put one organization over the other, even resorting to sabatage.  I guess its like that, with everything in life, not a lot I can do about it.

Steve       

[edweldon]

Steve - You and I could easily kill a desert sunset and a pile of firewood sharing war stories about our esperiences with American "business" and how enterprises sink to a level that matches that description.  I do think the SCTA has a ways to go and plenty of good roadblocks on that road.  Hundreds if not thousands of "owners" some of them noisy like those of us who play in this forum helps.
Interesting thing about this roll cage discussion.  It's had me exploring the subject and I've learned some new and important things that relate to my own project. Kinda amazing what we can learn from each other.
Ed