Motorcycle design layout questions for streamliners

[vespazari]

My name is Nate and I am writing from Australia , I am attempting to build a LSRacer so that I can participate in the  DLRA races held in Lake Gairdner South Australia. Since the DLRA runs on the basic rulesbook that is presented by SCTA. I figured why not ask for clarification here as well.

My current design is for a 125cc monocoque frame streamliner, under the current rule interpretation is it safe to assume that only a reclined feet forward racing position is permissible? Or is a head first design allowed in a streamliner?
 
the closest vehicle that I have seen with a head first rider position was in a partial streamliner, is the fact that rider must use safety restraints,harnesses the reason for the change in position, or is there another reason I am overlooking?  any input would be appreciated.

[Nortonist 592]

The Costello Rock 'liner (5050B) is a head first 'liner.  If you poke around the SCTA site I think you'll find some photos.

[RichFox]

I believe Jim Deist made the safty harness for Jack's 5050.  Seems to have a remote, cable release.

[Dean Los Angeles]

If you were standing where they are, you would see Nick's back. His head is underneath near the front "windshield" just behind the front wheel.



Your design limitations are only based on safety. It's pretty much wide open.

The 5050 streamliner has the record at 151.481 mph. Something to shoot for!

[Seldom Seen Slim]

Well, maybe you'd see Nick's back.  The last time we saw the #5050 run, at World Finals '07, it was piloted by a young lady (sorry, I don't remember her name).  She told me the story about it -- but I do think she's now the regular rider and Nick has gone on to other projects.

But yeah, the rider is belly-down and head first.  For good details see the DVD "Bonneville Wide Open", which features Jack Costella and Andy Sills (I think that's who was his first rider in the bike) and quite a bit of information about the little bike.  "B W O" is available from Benn Karne, a frequent contributor on this forum.  If he doesn't pick up on the thread you can find him in the "members" folder.

PS  The shameless plug about the DVD is prompted only by my selfish ego -- since Nancy appears in the video, too, and there's even a few seconds of me.

[Sumner]

I have pictures here:

http://purplesagetradingpost.com/sumner/bville%20bikes-3/5050-2006.html

and here:

http://purplesagetradingpost.com/sumner/bville%20bikes-3/5050-2007.html

c ya,

Sum

[1212FBGS]

you may be able to lower FA with a cranium forward riding posisition but the sensation of speed is much higher.....inner ear balance with a total flat riding posisition is also affected....one other overlooked point is being able to see out of your helmet.....put your helmet on and lay on the floor, can ya see out of the eye opening?
you might want to consult your local motorcycle rules commitee about the monocoque chassis.... I thought your rules closely followed the SCTA rules... if so your proposed chassis design would not be legal...
kent

[Stainless1]

....one other overlooked point is being able to see out of your helmet.....put your helmet on and lay on the floor, can ya see out of the eye opening?
kent

Maybe that's why they changed riders, to one that's "propped up" a bit in the front....

[Seldom Seen Slim]

Stainless, with all due respect to all parties involved, she wasn't Nancy, that's for sure.

[Nortonist 592]

I was looking at it in line a while back at E Mirage.  The harness latch is on the riders back with a release cable running up front to the riders hand.

[Dr Goggles]

you may be able to lower FA with a cranium forward riding posisition but the sensation of speed is much higher.....inner ear balance with a total flat riding posisition is also affected....one other overlooked point is being able to see out of your helmet.....put your helmet on and lay on the floor, can ya see out of the eye opening?
you might want to consult your local motorcycle rules commitee about the monocoque chassis.... I thought your rules closely followed the SCTA rules... if so your proposed chassis design would not be legal...
kent

....while watching the sun go down at Lake Gairdner  a few of us were talking and the topic of that riding position came up...One of the guys asked had we considered it for what we were building ...no! It was more the car guys who had a look of alarm about the suggestion and the agreed feeling was " if I'm going to be going that fast something inside me wants my feet in front of my face" however I think there is more to it .Kent's point about balance is one I hadn't thought about , I knew the sensation of speed would be different ...there are other points to consider , you can't breathe as well when you're lying on your chest  and your body is close to the limit of it's range of movement too, that is your back doesn't bend much further and so shock won't be as well absorbed.....Finally for someone with a damaged neck the the prospect of watching telly in that position is bad ..let alone racing ..

OK that said when I was a kid I built a billy-cart that was a long plank ....that I lay head first on and rode down the only decent sized hill in our area , great low centre of gravity ....didn't feel that in control though and the bail-out prospects weren't that good.....It didn't have a long career , not sure but I think my dad may have spirited it away...

Lucky Kaiser's recent 'liner was a piece of steel pipe and despite his protestations about it's strength it "didn't have a roll cage" and they wouldn't let it run under the DLRA rules ,




It is possible ,Vespazari ,to make the mistake of trying to "think outside the box" without first having a proper rummage through the "box" itself.........If you spend time going over every 'liner you can find you will see myriad approaches to a relatively simple pursuit . With a lot of looking time you will get a better idea of what you are capable of creating because you will see that the options are fairly narrow , the nut is the very fine detail......

[JackD]

THIS NEEDS A CHAPTER IN A BOOK

The last words will not be "The End", but "Don't make the same mistake the first time."
Their are a number of very good reasons to not build it the way you propose.
Kent touched on some of the operator reasons and there are many more.
Take rider position for example.
If your head is at the limit of it's travel in an unnatural position, what is going to happen when you crash ?
If the mass of your body is allowed to surge forward, even if restrained every way there is, you will break your neck.
The limited visibility of the liner that was mentioned has already resulted in a near miss at El Mirage that has caused considerable concern.
The required construction methods are minimums and stress skin or supplemented by other methods is allowed and encouraged.
Kent has the remains of a bike designed liner that crashed well over 300 mph and it is a good lesson on survivability.
The largest part was the rider compartment and he went on to make LSR history at speeds more than 100 mph faster.
 

[Dean Los Angeles]

[bones]

Nate, passenger?? If you're the fella I'm thinking of come over and have a look at the bike I'm building and we can talk all things salt.I'm sure can help in the wright direction.If you can't find my number, email is bonesracing25@yahoo,com.au. Maybe you could streeech a vespa (bring beer :lol)
cheers
             Bones

[Sumner]

...........................My current design is for a 125cc monocoque frame streamliner, under the current rule interpretation is it safe to assume that only a reclined feet forward racing position is permissible? Or is a head first design allowed in a streamliner?

I can only see an advantage of head first if you are running a very small engine, which you are.  Once you get to say 750 cc and up the frontal area of the motor is going to give you enough frontal area to be in a more conventional lay-down foot first position that has been tested in many crashes.  You can also see that Jack has used the conventional feet first approach for the Salt Snake probably due to the fact that it has to have enough frontal area for the larger motors they plan on running.

What if you do the head first and the racing organization takes a look at it and somewhere down the road decides that maybe this is not best in the interest of safety and bans it?  Then you are more or less screwed and will have to start a whole new build. 

 

http://purplesagetradingpost.com/sumner/b-ville%20meets/2006%20BUB-5.html

Eric and John have done an exceptional job with the lay-down feet first streamliner and have run speeds that are in my opinion more impressive than the 5050 liner (not to take anything away from them).  I think the 5050 has started to run a 50 cc motor, so maybe we will have some head to head competition between the two of them.  My money is on John and Eric.

c ya,

Sum