Landracing Forum
Tech Information => Safety => Topic started by: 4stroke on June 13, 2015, 11:52:50 PM
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Hello I am trying to learn how to design an effective light weight roll cage for road use. Can you direct me to a good resource with information regarding how much of a buffer should I use around my body and head, how much protection for front and rear end collision with car/tree. Straight vs curved tubing. Minimum tube thickness and diameter to keep weight low.
I have heard that Buddfab 50cc streamliner is 725lb with driver and Baumm NSU Streamliner is 2171bs without the engine this is too heavy/slow for street driving.
Without suicidal ejection (been there not fun) like conventional motorcycle I need the cage to protect me from:
Low slide up to 110kph
High slide up to 110kph
Rolling at 110kph
Car rear ending me at traffic lights at 70kph
Front end car pulling out in front of me/tree at 70kph
Also need to be able to
Lane filter
Use motorcycle parking (max 280cm)
Maneuver car parks
Put the foot down at traffic lights
See the road ahead of me
I hope you can direct me to relevant information so I can design an effective build-able design for an engineer to certify.
I am also tossing up the idea of using 125cc engine but I need to figure out what the whole bike will weigh then I'll know what engine will be suitable.
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You're looking for the impossible, especially when you're looking for an engineer to put his stamp on such a design. Those of us involved in racing know that no matter what the design there is risk involved whenever you get in a race vehicle.
Good luck. I think you're chasing the impossible dream.
Pete
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There are race vehicles that just don't transfer to being streetable, now that you've brought it up, a bike liner would probably number 1 on that list. You should really spend some time conversing with the logic side of your brain on this one.
Sid.
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You should really spend some time conversing with the logic side of your brain on this one.
Sid.
Awesome! :cheers: :cheers: :cheers:
seriously, 4stroke ........... buy a car
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http://blog.hemmings.com/index.php/2013/12/12/cars-of-futures-past-peraves-ecomobile-monotracer/
It's been done, with some success, even limited mass production. Never could get to critical mass to sustain itself though.
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I have heard that Buddfab 50cc streamliner is 725lb with driver and Baumm NSU Streamliner is 2171bs without the engine this is too heavy/slow for street driving.
I am also tossing up the idea of using 125cc engine but I need to figure out what the whole bike will weigh then I'll know what engine will be suitable.
How heavy and fast is you current bike... :evil: :dhorse:
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The Buddfab weighs about 575 with driver. Years ago I gave an incorrect number during a hot afternoon Bonneville interview and it has been repeated often.
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Interesting memories from your ideas: Snap open, rearward sliding lower doors was the best system tried during some study done about 30-35 years ago. The doors had to be "open" above hip level when the rider pushed the thumb release lever. Test riders felt this would be dangerous in a simple low speed fall. At that time, the mechanism was spring loaded with a long lever to pull them shut.
Another problem found during testing, I was told, was rapid front tire wear under almost all riding conditions and very difficult brake control. I never got to see any of this stuff, but was contacted to discuss ABS methods for a possible sidecar type adaptation. The language difficulties made our discussions complicated, but I know the sidecar type design became a dead end. Keep in mind, this was all many years before the advent of modern VSC, multi-channel integrated ABS, and computer controlled electronic power steering systems.
Across the other ocean, Honda did some really good work on motorcycle design safety and found the best solution is to eject the rider cleanly with as little injury as possible during the actual impact/rider ejection event. The production result was the PC800, which you can still find good ones on the used market.
If you find one, you should fabricate a short handle, large Hex head tool to replace the O-rings on the sides of the cylinder heads. The fully enclosed engine tends to cook seals and O-rings on these bikes, which means you can often buy one cheap due to the oil leaks. That was how I got mine, many years ago. Don't have the bike, anymore, but still have the tool if you need to use it! Wonderful bike, by the way, and incredible gas mileage for something that can cruise so fast (but they eat front tires).
Physics is against you on this idea, and there has been some pretty big money spent to prove that fact.
JimL
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Interesting reply JimL.
Here is how I see it.
Cars are too big, heavy, slow, have too many wheels, drink too much fuel and cost too much to own and run. They can't filter, they can't use motorcycle parking, I cannot put my foot down at lights in a car and I only ride motorcycles. Plus motorcycles are cool.
Motorcycles have too much frontal area, aerodynamic drag, fuel consumption and they are unnecessarily dangerous (low slide, high slide).
I want a combination of the two to create an optimal vehicle to meet my needs. Minimal frontal area, minimal aerodynamic drag, remarkable fuel consumption and reduced danger during low slides, high slide and rolls. I think it is a great idea.
487.883lb is my combined vehicle weight.
575lb with driver sounds pretty good for Buddfab 50cc.
Can anyone direct me to roll cage building resource? It seems the internet is saturated with roll cages for cars.
I am thinking of using mid engine design, the following fellow was able to build his bike weighing less than the original but it does not have roll cage resulting in his injury.
http://rohorn.blogspot.com.au/
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I don't know anything about a roll cage building resource. I think your best bet it to attend a LSR event and look at what's there. No two will be alike. You could talk to the builder of the Bub Fab bike and others for their thoughts.
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I don't know anything about a roll cage building resource. I think your best bet it to attend a LSR event and look at what's there. No two will be alike. You could talk to the builder of the Bub Fab bike and others for their thoughts.
I was thinking there would be certain rules like they have for F1 cars and dragster roll cages. I remember reading one build thread about how the roll bar protecting the head had to have minimum space to prevent head and spinal injuries if you hit the roof. That would be good information to have.
There is lsr in Australia I have sent an email regarding roll cage information.
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Are you in Australia? Then yes, I would think a DRLA rule book might have the cage requirements to compete at their event. As does the SCTA rule book here. But it is a long way from a blueprint for building a cage.
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One other thing to keep in mind is once you are strapped in with a harness you really need to be thinking head and neck restraint.
A three wheel vehicle despite the other drawbacks and failing to meet your other criteria is pretty much the better solution
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. . . Can you direct me to a good resource with information regarding how much of a buffer should I use around my body and head, how much protection for front and rear end collision with car/tree . . .
I can't begin to imagine how much protection one would need on a motorcycle if a tree collided with it from behind.
Without suicidal ejection (been there not fun) like conventional motorcycle I need the cage to protect me from:
Low slide up to 110kph
High slide up to 110kph
Rolling at 110kph
Car rear ending me at traffic lights at 70kph
Front end car pulling out in front of me/tree at 70kph
Also need to be able to
Lane filter
Use motorcycle parking (max 280cm)
Maneuver car parks
Put the foot down at traffic lights
See the road ahead of me
You have many needs.
For a street driven motorcycle, I think your parameters are unrealistic.
Have you considered a decent helmet and leathers, or possibly a course in defensive driving techniques?
Okay, I am being a jerk. But you're looking to build a lightweight cocoon on 2 wheels with survivability against calamities few cars weighing 8 times more than what your proposing are expected to survive.
That's a tough need to fulfill.
Chris
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Seriously, let me illustrate my point.
Here's a series of vehicles hitting a short wall at 40 mph, which translates to 64 kph -
https://www.youtube.com/watch?v=zk5cp93zefk
Upon collision, the bike and rider will go from 0 to 64 kph virtually instantaneously, and the car will continue it's forward progress.
You'd likely be looking at about an 18 G impact. Might be survivable, but for a vehicle less than 10 feet long to absorb collisions like this with a human being aboard, you'd be hard pressed to find materials that would be as light as you propose.
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You started out talking motorcycle streamliner but you are referencing a reconfigured motorcycle & talking enclosure, thats really a different animal. A bike liner in our world is structured & caged to protect the "driver" from a solo vehicle crash in an environment where there are no structures or other traffic that will squash you like a bug. Motorcycle survivability on the road is hinged around being seen by other motorists & being able to leave the bike "when" you crash & you are looking at eliminating both of these. That is going to make one very dangerous vehicle.
I built a street legal bellytank a few years ago, it's a two seat tandem configuration with a chassis built to SCTA spec, it will run over 200 mph & eye level is 32" above ground level. That one thing alone makes it a death trap in traffic, I can't see & others can't see me. No mater how much steel there is around me, I'm a bug in an unseen target. Fortunately I live in the country & my biggest risk is running under a deer or an elk but city traffic is out of the question.
I'm sure there are other forums with like minded people like yourself, we are LSR people. It's kinda like a sail boat guy asking a hydroplane racer for advice.
Sid.
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It sounds like what you are asking is what our guidelines for building a streamliner are. The rule books for SCTA and BMST don't really give any specific info but do give minimum guidelines for building one. The link to the AMA (BMST) rules is here http://bonnevillespeedtrials.com/wp-content/uploads/2014/02/AMA-LSGC-SR-2015v13.pdf SCTA's rule books can be purchased for $10 from their website. It's probably not exactly what you are looking for in a street application but could give you an idea of how it works for land speed racing application. My biggest suggestion would probably be go to an event and see how others have built their streamliners then use that to get ideas for your project. My personal opinion is a motorcycle streamliner isn't a very streetable thing typically but that may also be because I am designing one for the salt and haven't thought too hard about what would be needed to make it work in a street situation.
Did a quick google search and came up with this one, might look more in to it, seems fairly streetable. http://www.gizmag.com/suprine-exodus-recumbent-motorcycle/28398/
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The reason I mentioned trees is because I hit a telegraph pole with my knee. The collision was not head on (I would have died) the telegraph pole caught my hand/handlebar which hit the tank and the telegraph pole then caught my knee, the resulting force ejected me but not before breaking my femur. Had it not been in an urban area where people could hear my cries for help I would have died from blood loss.
Despite this I am still riding my bike and I see a need for better protection without resorting to massive 1 ton car.
Regarding rear end collision with a car. Most rear ends I have seen shunts the rear wheel sending the biker into an unexpected wheelie before they fall to one side (if they are lucky). I can see how falling onto a roll cage instead of the bike falling onto you would be the better option.
I have considered three wheel but I do not know if I can get the wheels close enough to allow filtering and motorcycle parking. I think tilting steering may be too complicated. I did thought about making a petrol powered "velomobile" but the bicycle people did not like the idea of someone making a petrol powered hpv vehicle...
I have a bit more to say but I am busy right now.
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Okay, cars are too slow, 2,000 lb cars are too heavy, but you advocate filtering, and you travel swiftly enough in an urban area to eject yourself and break a femur by hitting a telegraph pole.
The problem clearly lies with the bike, but I doubt a mechanical engineering exercise will be of much benefit.
Have you considered modifying the guidance system?
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Yea, ya gotta watch them damn poles, they move a lot faster than you think they could... :roll:
First question... how long have you been riding
Next... How long on the bike you crashed
Next... How fast do you ride normally, how fast when you crashed
Next... Why do you want a cage... do you realize it will kill you unless you are securely strapped in with all extremities confined unless you want to lose one that can get out.
Maybe you need to make yourself more visible, do you wear a bright orange reflective vest over your leathers every time you ride.
:cheers:
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What's a massive one-ton car look like?
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Sorta like a 1800 lb MC streamliner with the extra 200 lbs of suspension and wheels to make it a car...
:evil:
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Take a riders course and ride to live. The road isn't any safer than you are :dhorse:
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What's a massive one-ton car look like?
Note the massive bulk and gas guzzling nature of the aforementioned 1-ton behemoths.
(http://i361.photobucket.com/albums/oo58/milwaukeemidget/DSCN4714.jpg) (http://s361.photobucket.com/user/milwaukeemidget/media/DSCN4714.jpg.html)
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Filtering in Australia is legally defined as moving between vehicles on the right side at speeds less than 30kph. I am by no means a Rossi wannabe.
The human guidance system is not very good in the wet, at night or down nightmare road (where I crashed). But even in the best of conditions mistakes can be made and often are. On a motorcycle this means hospital or worse.
Sure I could catch the bus or never leave the house but I want to get the right balance or safety/risk, efficiency, economy, convenience and performance.
By efficiency I do not mean 40mpg I mean the highest practical mpg. 235mpg+ on the high way.
I am reading through the rule book that was linked for ideas. Thanks for adding that to the thread.
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Once you install a cage you have to ensure that none of your limbs can in any way extend beyond the limits of the cage. That means you can't put your feet down or extend an arm outward because if it's possible in normal operation then under the force of an accident your limb will certainly get outside the cage and the cage will likely severly injure the limb that goes beyond the extents of the cage.
While you're at it, why don't you go into your profile and change your location to where it actually is. :-D :-D :-D
Pete
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http://www.motorcyclistonline.com/pace
:dhorse:
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A quick comment: I've taken FIVE on-track riding schools, and each and every one of them has had the condition that the course goes on rain or shine. So I have been taught some rain-riding techniques. Not that Valentino has anything about which to worry when he and I are both riding in the wet -- but I am pleased to say that I've been taught at least some of the stuff needed to improve my chances when the rain is a-fallin'. I threw the CBR1100XX down the road at Grattan - in the wet. I tossed the EX250 into the weeds at Road America - in the wet. I learned from those two rides, though. It weren't fun - but at least I can brag that I've tried to learn some.
Et vous?
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I see you changed your location. Thank-you. :-D :-D :-D
Jon's full of wisdom this morniing. His advise on high performance riding schools will do way more than a roll cage to save you from grief................ or worse.
Pete
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I agree with all replies from #22 on. Take the advice :dhorse:
DW
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I have decided the best design for low frontal area and safety will be recumbent reverse trike. I won't need a roll cage since I'll design it to have a low enough center of gravity (also improving frontal area). I am now trying to figure out a strong light weight frame and the suspension. I'd like to get the vehicle weight under 100kg but lower the better for acceleration.
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That certainly looks doable.
Please show us a video on fire-up day.
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Just for your information you've just reinvented the Morgan 3 wheeler. It worked well for a long time. Modern technology should improve it. You may also want to Google Elio.
Pete
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Just for your information you've just reinvented the Morgan 3 wheeler. It worked well for a long time. Modern technology should improve it. You may also want to Google Elio.
Pete
And the Can-Am Spyder, sans roll cage.
:cheers:
Fordboy
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It looks to me that the helmet replaces the roll cage. Might need some reinforcement.
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The Morgan is now back on the market.
Sid.
https://www.google.com/search?q=morgan+3+wheeler+usa&rlz=1C1OPRB_enUS639US639&espv=2&biw=1280&bih=605&tbm=isch&tbo=u&source=univ&sa=X&ei=_TOGVdGgHIzuoATbmIb4AQ&ved=0CCkQsAQ
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I think you're going to have to compromise quite a bit. You can't have extremely
light weight, extremely great crash protection, and extremely great performance
all at the same time.
I hope some of the ideas others have posted in this thread are "sinking in" . . .
Regarding good fuel mileage, you could research what Doug Malewicki did. He
has a nice website that describes/shows a street-legal motorcycle that was
demonstrated in California quite a while ago. Its fuel economy was quite
impressive. Yeah, there were also some compromises. For example, no
"jackrabbit" starts. Doug used to sell plans for building a similar vehicle. I
don't know whether he still does, though.
And by the way, I used to have a (totally stock, unmodified in any way) Honda 50
that got about 200 miles/gallon. It wasn't very fast, and had no heavy roll cage.
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Hey 4stroke
How are you going to get this registered?
Bones