RFL

[cros]

Hi folks on reading your banter and facts from all of you there are some physics that would not be possible to our type and hope I can mention some of these factor that will help yourselves to conclude that would reduce our road fund for our bikes as the first suggestive post by slparry! [ ] `I have kept this one penned`

Aerodynamics I believe will have a large factor and help with your conclusions to the facts of weight to drag ratios.

bikerbones quoted on page 2

I had this discussion with a non-biking friend some time ago, who was asking what the performance of my Blackbird was like against modern supercars. I stated that on acceleration, it would take a very serious car to even get anywhere close to it from a *rolling start up to 140mph or so. I then explained its power/weight ratio and the performance potential hits home (ie 145-150bhp at the wheel pushing 220kg or so) ie 650+bhp/tonne.

However, its top speed is nothing like what one would imagine it should be, bearing in mind the power to weight. There are many cars going a fair bit quicker, on a much lower power-weight.

Said friend was slightly baffled at this but it's simple - as BnB said, bikes' aerodynamics are pretty dreadful. Above 100mph, a huge amount of the engine's oomph is taken just to battle against the drag of the air. Cars win back very convincingly.

To consider "Parasitic drag" which most manufacture have tried to prevent by streamlining bodywork. "Avoiding Gromit`s wall of air."

To consider "Induced drag" is where the golfer whacks his balls through the air and relies on this to keep control of the direction he has to hit his target.
It is a drag that aircraft manufacturers have tried to avoid and is created from the surface of the bodywork, (i.e.) Fuselage and wings, This drag also increases as it accelerates through the air.

To consider "lift" as we do not want to achieve any of this on our two wheels we look for the opposite to make it safer, and yet I believe this is the results from a four wheeled vehicle being lifted and relieved of the pressure on the surface of the road, `thus less drag` being a combination of friction and induced.

Cars are like a aerofoil wing in design and looks! Get the combination right as to the ratio of its two lifting properties as a wing and they have opprox 30/40% compressed lift on the bottom surface and 60/70% lift on the top surface by reduced pressure.

Look at Donald Campbell, his boat flipped in flight but he had no control after he endured his achievement and that was to fly his boat to reduce the drag factors.

It would be nice to overcome Gravity, then our future controllers! “The Planet of the Apes” will charge us `Air Miles`

[cros]

Hi folks on reading your banter and facts from all of you there are some physics that would not be possible to our type and hope I can mention some of these factor that will help yourselves to conclude that would reduce our road fund for our bikes as the first suggestive post by slparry! [ ] `I have kept this one penned`

Aerodynamics I believe will have a large factor and help with your conclusions to the facts of weight to drag ratios.

bikerbones quoted on page 2

I had this discussion with a non-biking friend some time ago, who was asking what the performance of my Blackbird was like against modern supercars. I stated that on acceleration, it would take a very serious car to even get anywhere close to it from a *rolling start up to 140mph or so. I then explained its power/weight ratio and the performance potential hits home (ie 145-150bhp at the wheel pushing 220kg or so) ie 650+bhp/tonne.

However, its top speed is nothing like what one would imagine it should be, bearing in mind the power to weight. There are many cars going a fair bit quicker, on a much lower power-weight.

Said friend was slightly baffled at this but it's simple - as BnB said, bikes' aerodynamics are pretty dreadful. Above 100mph, a huge amount of the engine's oomph is taken just to battle against the drag of the air. Cars win back very convincingly.

To consider "Parasitic drag" which most manufacture have tried to prevent by streamlining bodywork. "Avoiding Gromit`s wall of air."

To consider "Induced drag" is where the golfer whacks his balls through the air and relies on this to keep control of the direction he has to hit his target.
It is a drag that aircraft manufacturers have tried to avoid and is created from the surface of the bodywork, (i.e.) Fuselage and wings, This drag also increases as it accelerates through the air.

To consider "lift" as we do not want to achieve any of this on our two wheels we look for the opposite to make it safer, and yet I believe this is the results from a four wheeled vehicle being lifted and relieved of the pressure on the surface of the road, `thus less drag` being a combination of friction and induced.

Cars are like a aerofoil wing in design and looks! Get the combination right as to the ratio of its two lifting properties as a wing and they have opprox 30/40% compressed lift on the bottom surface and 60/70% lift on the top surface by reduced pressure.

Look at Donald Campbell, his boat flipped in flight but he had no control after he endured his achievement and that was to fly his boat to reduce the drag factors.

It would be nice to overcome Gravity, then our future controllers! “The Planet of the Apes” will charge us `Air Miles`

[Corvus]

I know next to nothing about aero drag, so help me along here.

Looking at the motorcycle compared to car scenario, am I right in thinking that, within the broader category of parasitic drag, form drag is the one which is most applicable? Am I then drawing the right conclusion by saying that two fundamental aspects apply; the frontal area and the longitudinal shape?

In my naive way, again looking at a comparison of motorcycle and car, I see the motorcycle as scoring high in frontal area but low in longitudinal shape and the car scoring the opposite way around. Is that a fair appraisal?

Based on the above, I then wonder whether the bikes' narrow frontal area will make up for its lack of a streamlined longitudinal shape, in the bike/car comparison scenario?

I realise I have just built a very naive house of cards there, with each successive naive step held up by the one before it, so if anyone can help at this stage that would be appreciated.