Brand new at this please help !

[taper41]

I know that some of these question i have might be elementary to you folks that are veterans at this but please help to inform me of some of the simple questions due to a study that i have been doing for physics....

in a perfect world where traction was not a problem, when trying to reach top end speeds, is it more advantageous to have the streamliner equipped with 4 wheels like a tradition car or 2 wheels like a tradition motorcycle, lets keep the wheels all at the same with for either vehicle for a controlled variable and say that both liners have the same weight and power along with same dimensions. theoretically wouldn't the motorcycle style have a lower drag thus  enabling it to reach higher speeds.

from the outside looking in i dont understand how the 4 wheel streamliners have been able to reach higher top speeds
wouldnt the 2 wheel design be more efficient for top speed

as silly as this might be i thank whomever helps me with this

[fastman614]

WOW!.... This is an interesting question!.... I am going to stick my neck out and say this....

In the context of the time and date that A LOT of the streamliner records have been set, you will see that, unless you look at BUB/AMA, where a scant few of the 3000cc records have recently been set at speeds comparable to the equivalent sized engines in a 4 wheeled vehicle, that a lot of the existing motorcycle records were set in an era that is now long gone.... the car records have been fairly actively challenged and, often, have been successfully set ever higher .... the motorcycle records have NOT been challenged anywhere near as often.

The biggest reason that I, as a 40+ year veteran of land speed racing and a former motorcycle competitor, can see and possibly relate to, is that building a motorcycle streamliner is not something that the average motorcycle enthusiast has much interest in taking on. The people who have built streamliner motorcycles over the past 40 or so years have often been the "same" group of people - i.e Vesco's, Sam Wheeler, Dennis Manning etc... many of the attempts that have shown up over the decades have not met with a lot of success - the handling of a motorcycle streamliner remains at what I would call an "inexact science".... You need only to look at the efforts of Harley, Honda and Kawasaki back in the 70s, Vesco's all throughout land speed history, Dennis Manning, Jammer, Tatro's, Vance Breese etc.... The "fact" that the crash ratio is very high with 2 wheeled streamliners vis-a-vis 4 wheeled streamliners is pretty much enough to make most of us who want to go "real fast" to try it a "different way" - even with motorcycle power.... that "different way" is often or usually with 4 wheels.... the handling of a 4 wheeled streamlined vehicle is NOT IN ANY WAY comparable to a 2 wheeled streamliner (there are "experts" who will tell you this).... thus, a decision as to the mode of "transportation" gets made according to empirical data in regards to crash statistics and other factors....

In our own personal situation, we were "knocking on the door" of 200 MPH in the late 1970s (we had a turbocharged Kawasaki KZ1000 that was probably capable of 235 mph a way back then - traction was our big issue).... and with families, businesses and insurance issues with which to grapple, we decided that roll cages and four wheels was a somewhat more logical method of pursuing our land speed racing goals... We started out with a massively rebuilt Chevy Vega coupe that has, in its most recent formm gone well over 250 mph and, subsequent to the successful competition with that vehicle over the past 25 or so years, we built a lakester - an open wheeled "special construction category car that is a current record holder in its class and is capable of way over 280 mph.... incidentally, the car steers with one hand....

I do hope that several other of the "heavyweights" also weigh in on this thread for you....

[taper41]

Fast man thank you for your input, so handling is whats suspect here? In a perfect world if handling wasnt an issue wouldnt the two wheel design be able ro reach a higher top speed due tohe fact it has less points of friction. Or are there other advantages to having four wheels even if you take the variables of handeling and traction out of the design. Theoretically what would be faster, would it not be the less wheels the less , the higher the top speed

[dr j]

Taper41,
I suspect that most of us reading your post are confused by your pinpoint focus on a single aspect of making an LSR vehicle fast.  While I agree that each aspect of a project needs to be examined alone first then that aspect must be combined with all the others to see the total picture.  Obviously if everything about the wheels/tires are the same then 2 will have less drag than 4 both for the rolling friction on the salt and for the aerodynamics of protruding below the main shell.  However handling and traction are a big deal on the slippery salt surface and there the 4 tires positives easily will outweigh those coefficient drag negatives. 
Also I totally agree with fastman that a project needs a passionate leader.  Most motorcyclists (like me) are happy to sit on their bikes rather than be strapped into a car/missile that is missing 2 wheels.  I am in awe of those that do.

[taper41]

Dr, J

      lets say that the racing was taken to a surface that allowed for more traction, is that the main part of the difficulties handling a 2 wheeled streamliner, does having 4 wheels have any other advantages when it comes to top speed besides the handling aspect?

now that i think of it , wouldn't a vehicle with 4 wheels withstand the forces that are working against the streamliner more so than a 2 wheels, another words if both vehicles were racing side by side and were increasing speed simultaneously would the vehicle with 2 wheels fail to hold up against the resistance before the 4 wheeled vehicle would ?

[fastman614]

Fast man thank you for your input, so handling is whats suspect here? In a perfect world if handling wasnt an issue wouldnt the two wheel design be able ro reach a higher top speed due tohe fact it has less points of friction. Or are there other advantages to having four wheels even if you take the variables of handeling and traction out of the design. Theoretically what would be faster, would it not be the less wheels the less , the higher the top speed

You must understand a thing or two about Bonneville racing.... The bulk of all competitors are "backyard" mechanics. You are posing a rather point question that is rather narrow in scope. Your "qualifying" of the
question with the term "in a perfect world", in my mind, tends to roil the issue....Bonneville is rarely, if ever, a perfect world....those of us who have been involved for several years don't tend to look a lot at the theory of what we do - we tend to look a lot at who else is doing "what", why are they doing "it" and are they achieving greater success than we are?

Bonneville is a place where few, if any, of us will really try to "re-invent the wheel"... the cars that show up - from production class cars to all out special construction streamliners and literally everything in between are usually constructed in someone's home garage.... often after years of collection of anecdotal data - usually by attending Speedweek and other land speed events, looking at the cars that are in the category for which a desire is in place to build and run a car, taking a lot of pictures, asking a lot of questions and then building the car. Most of us would not know, for instance, how to engineer a steering system. But - we DO know how to install a set of components - either reproduction hotrod or OEM - from an existing car - i.e. a 4" dropped axle from Speedway Motors catalog along with spindles, steering arms, tierods, suspension, and  then a steering box -whether it be a Ford 60s style (using an "almost upside down" method of installation that Ford never used with the box in question) or a Chevy Vega steering box with a cross link - during the installation of which attention is given to designing in the ability to obtain the correct caster and camber. After this is built into the car, there remains a steering shaft with a usually removable steering wheel to be put in to the car.

I know that it is not directly related to streamlined cars and motorcycles and which, with all other things being equal, will go faster but it should give you an indication as to the nature of our land speed obsession and how race vehicles get built. There aren't a lot of us who can expound on the theory of doing it - we just seem to be able to figure it out by what works on other cars, what we know from other applications will also work and some, if not a lot, of trial and error.

Dr j, in his post, made a salient comment about the wheels/tires being the same and that 2 will have less drag than 4 - both for rolling friction and aerodynamics - but, as he also goes on to state, handling and traction  are a big deal as well.

Suffice it to say that there are NOT many of us who have the engineering expertise to explain the theory in relation to the fact that most of the motorcycle vs car streamliner records do not provide evidence in favor of what the theory suggests.... But I do stand by my earlier assertion from a previous post.....

[taper41]

 These questions are relative to the physics aspect, from which i am studying more so than the variables of lad speed racing itself, though i do understand that there are variables on which you have to take account for.

But what i was implying from a physics point of view that the advantages of 2 wheel are obviously that there is less drag but what dr. j pointed out got me to thinking that along with the advantages of having only two wheels there disadvantages. am i correct or incorrect on thinking that along with having better traction and stability , that a car with 4 wheels would withstand a greater amount of resistance and opposite forces working against the streamliner, another words would the streamliner with 2 wheels fail under the forces and pressure before the vehicle with 4 wheels under the same conditions

[hotrod]

In any engineering task you are always trying to balance costs and benefits (not in dollars necessarily but energy as well).

For example, due to the higher stability of 4 wheels the driver can spend less  time and effort trying to keep the streamliner upright and more time and effort driving. In a 2 wheel car every time it weaves slightly to maintain balance you are subtracting from the goal of speed. Due to the low stability of the 2 wheel streamliners they are VERY restricted on wind conditions that they can run in. The very fastest may only get 1 or 2 times a day where the wind is dead calm over the entire length of the course. If they are not ready and waiting when that happens they lose the opportunity. The 4 wheel streamliners in contrast can run in very light wind conditions that are unacceptable for the bike streamliners. It is not uncommon for the bike streamliners to sit there for hours waiting for the ideal wind conditions to run.

Now if you removed that issue by running in an imaginary wind free environment then you can focus on other issues. There are several forms of drag a car must over come. The most important at high speed is aero drag, this is dominated by the shape and size of the vehicle. In theory the 2 wheel streamliners come out ahead here because they are inherently smaller vehicles. Less frontal area translates to lower over all aero drag. But that reduction in size imposes other limitations. Smaller size also forces unnatural driving positions on the drivers. Motorcycle streamliner drivers are nearly prone, that reduces visibility and also makes it difficult to sense balance, returning back to the stability issue. The small size also limits the size of engine that they can use. One of the key limitations for the top streamliners is making enough power to overcome aero drag but also keeping the engine alive for the necessary distance without it getting so hot the streamliner catches fire at the end of each run.

Here the larger size of the 4 wheel streamliners works in their favor. They can run a physically larger engine working at lower intensity to make the necessary power which gives them higher mechanical reliability, and the larger physical size reduces packaging issues of fitting all the hardware inside a streamlined body. More flexibility in packaging allows a bit more room for air circulation and cooling inside the body and relatively less risk of overheating the hardware during a run. Even in the 4 wheel cars (of all classes) there are several that are just on the verge of melt down or catching fire at the end of each run due to the tight spacing.

Last you also have rolling resistance which consists of the drag from bearings in each wheel (should be less on a 2 wheel than a 4 wheel car) but rolling resistance also results from the flexing of the tire carcase and the impression it makes in the salt as it rolls down the track. A lightly loaded wheel will have less rolling resistance than a heavily loaded wheel all else equal so the advantage goes to the 4 wheel car in most cases. As 4 relatively lightly loaded wheels will have less rolling resistance than 2 heavily loaded wheels carrying the same weight, not to mention the ability to get the power down is greatly limited by a 2 wheel streamliner. You have to put all that power through one tire. On a 4 wheel streamliner you can use 2 or 4 wheels to get the power to the track.

When you balance all those factors out and throw in psychological issues like the drivers perception of safety the net sum of all that comes out in favor of a 4 wheel streamliner. Many more of them are built. They are easier to build. They get more runs under typical racing conditions.

If 2 wheel streamliners could run in the same cross wind conditions as the big streamliners the benefit might shift in their direction, but historically the 4 wheel pattern has much more time at speed and that results in more records. Really high power engines have been available in sizes suitable for 4 wheel drive designs since the 1930's but ultra high power motorcycle sized engines are relatively new by comparison.

Each designer has to choose which problems he/she is willing to suffer with and which they can over come through innovation and sheer persistence. You can't have everything you want in your design so you make a choice and then live with the constraints it places on you as best you can.


Larry

[taper41]

Thank you larry for you specifics they do help out a lot, now you mentioned that the rolling drag is typically less on a 4 wheeled vehicle because of the lighter load, to go along with that would my theory that 4 wheels would hold up to greater resistance and downforce than two wheeled vehicles. would 2 wheeled vehicles fail first do to gravity and downforce before 4 just from a physics point of view not including the other variables that you have discussed as i know they are important when planning on a construction of a streamliner, but this is more from a pure physics stand point.

[fastman614]

Larry (aka hotrod) - Well written!

[jl222]

I know that some of these question i have might be elementary to you folks that are veterans at this but please help to inform me of some of the simple questions due to a study that i have been doing for physics....

in a perfect world where traction was not a problem, when trying to reach top end speeds, is it more advantageous to have the streamliner equipped with 4 wheels like a tradition car or 2 wheels like a tradition motorcycle, lets keep the wheels all at the same with for either vehicle for a controlled variable and say that both liners have the same weight and power along with same dimensions. theoretically wouldn't the motorcycle style have a lower drag thus  enabling it to reach higher speeds.

from the outside looking in i dont understand how the 4 wheel streamliners have been able to reach higher top speeds
wouldnt the 2 wheel design be more efficient for top speed

as silly as this might be i thank whomever helps me with this

  Having the same weight- power and dimensions and traction not a problem the motorcycle type wins '' think missle''.

  At Bville which has traction problems, 4 wheels for traction is better and you could easily get 7000 hp out of 2 fuel Hemi's
  [ 8000 + hp drag race out of one] and still have traction problems.

  I know of 2 single engined hemi powered streamliners being built with wings, one varible, which should help traction.

  Bville motorcycles have traction problems with 200 hp.

  The 4 wheel Bville cars go faster because of traction and room for more power.

   Still the motorcycles are getting close to 400 mph with way less power and lack Kamikazi pilots


                    JL222

  

                    

[dw230]

A whole lot of answers that still do not answer the original post. He asked if given equal factors is a 2 wheel vehicle faster than a 4 wheel vehicle. The easy answer is yes. Directly comparable is the F(3000cc) engine class in Blown Fuel Streamliner.

The motorcyle record, 2 wheels, is held by Ack Attack at 376. The Speed Demon, 4 wheels, holds the car record at 343. Granted one is FIM and the other BNI - different criteria for our op, but basic comparison of an orange to a hybrid citrus fruit. Both good for margaritas.

Conclusion is yes a 2wheel vehicle is faster given the exact same parameters.

DW

[taper41]

what about the previously mention rolling resistance, seeing as though from this conversation that the rolling resistance would be less of the 4 wheel vehicle because the the each individual tire supports less weight giving it less friction. is that two little of a factor ?

[Stan Back]

What if you painted one black?

[dw230]

If you use an engine larger than 3000cc you must have 4 wheels. Of course rolling resistance plays a factor - back the brakes off.

DW