Commando motor in solid frame

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Thank you Ken.

Now Rohan, show us your two points on any single curve on that chart! The numbers I am referring to and have always referred to are quoted from you:

"it is commonly quoted that ~10 hp is needed to do 60 mph,and ~32 hp to do 100 mph."

Use a french curve to honor the shapes of the example curves if you want. So where does the 10 hp land, eh Rohan? It does not fit the curves. No. So where do the numbers come from? Citation and basis for numbers?

But this is beside the point as you were trying to reconcile the: "it is commonly quoted that ~10 hp is needed to do 60 mph, and ~32 hp to do 100 mph." with the general equations for power to overcome aero drag which is adequately explained in the Phil Irving Tuning for Speed. Furthermore, Phil Irving points out the example numbers (manifested in the curve that Ken was so kind to post) to begin to calculate total power required factoring in aero drag power as well as such things as rolling resistance and maybe more.

The "commonly quoted that ~10 hp is needed to do 60 mph, and ~32 hp to do 100 mph" numbers are not the aero drag numbers; this had been a source of this confusion on the part of Rohan. That is why I suggested reading up on what Phil Irving , Tuning for Speed presented. The rest has been a Rohan subterfuge to save face.
 
Rohan said:
You seem determined for an arguement when there is none.
Click to expand...
So let's see, ......
I never had an issue with a 30 hp number Rohan latched on to from Phil Irving and has been expounding on,.....check
Rohan misappropriates my quotes to make it look like I am arguing with Rohans current 30 hp number (new Rohan number of the day), ........check

and I am "determined to argue"? :lol:

This is another Rohanism classic. :lol:

I certainly don't need to brush up on timestamps for posts unless someone else suggests I do so. The main point was the proper chronology which you did not get correct in your lame attempt to manipulate posts to save face.

Let's just politely say I have a low tolerance for Grand BS'ers and fraudster behaviour.
 
Rohan said:
Thankyou for your worthy negative contribution to this discussion Ashley

Maybe hobot will come back with something positive here
Click to expand...

So because a lot of poeple get sick of what happens with these threads and the way they pan out, so now you are going to take it out on me, well at lease I have done and how I done it to my Norton so I am now negative with what I say about Commando in solid frames, just because I am not the smartest of poeple on this site and understanding fact and figiues is hard for me, all I know is I spent a lot of time working and building motorcycles (mostly Norton Commandos and Feathebeds) I don't need a book to tell me how it needs to be done, I just do it and I nomaly get it right every time, but have also made mistakes, but I don't need a book to tell me that.

Hobot had his reasons to not say much these days because of what happens here sometimes, we all have our own opinions and everone should respect each others opinions without dragging it on because someone elses opinion is not the same as yours.

Ashley
 
jseng1 said:
This is my personal favorite style of Norton. A super efficient Commando motor with the vibration reduced by 1/3, mounted in a solid frame and set up cafe style.

Commando motor in solid frame
Click to expand...

And this is what it is all about and how it changed so quickly.

Ashly
 
ashman said:
Rohan said:
Thankyou for your worthy negative contribution to this discussion Ashley

Maybe hobot will come back with something positive here
Click to expand...

So because a lot of poeple get sick of what happens with these threads and the way they pan out, so now you are going to take it out on me, ....................
Click to expand...
Rohan, making new friends are you?

Rohan might I politely suggest the following reading for you titled How to Win Friends and Influence People by Dale Carnegie:

http://images.kw.com/docs/2/1/2/212345/1285134779158_htwfaip.pdf

I feel you are woefully lacking in these skills. Please go beyond looking at the pictures and make an effort to read the sentences and paragraphs. It appears that you have been having quite the difficulty on this forum so take your time.
 
An earlier version of this graph actually labels the actual graph lines. Through logic you can figure out that the top line is "C" with the corresponding legend "HEAVYWIEGHT MACHINES. From reading Phil Irvings text associated with this graph, it is not perfectly clear (to me at least) if the graph is indicating crankshaft power or only aero drag and rolling resistance power but the graph is certainly good enough to illustrate the significance of wind resistance power necessary to overcome at speed. The aero drag (wind resistance) power is proportional to the cube of the speed so one can use their imagination to visualize what it takes to go fast with these examples.

If the graph only depicts aero drag and rolling resistance power, then rear chain, gearbox and primary drive losses would need to be factored in. The additional losses usually amount to several percentage points of overall power. Phil Irving provides a nice simple example of the aero drag component in his text one page prior to this graph.


lcrken said:
FWIW, this is the chart Rohan is referring to.

Commando motor in solid frame


Ken
Click to expand...
 
ashman said:
jseng1 said:
This is my personal favorite style of Norton. A super efficient Commando motor with the vibration reduced by 1/3, mounted in a solid frame and set up cafe style.

Commando motor in solid frame
Click to expand...

And this is what it is all about and how it changed so quickly.

Ashly
Click to expand...

I guess Jim Schmidt, Ashley and myself must have similar taste...this is my bike without fairing:

Commando motor in solid frame

With the fairing, top speed is more than 10mph higher than without...Phil Irving was right, but we all knew that. :mrgreen:
 
Jagbruno said:
Commando motor in solid frame

With the fairing, top speed is more than 10mph higher than without...Phil Irving was right, but we all knew that. :mrgreen:
Click to expand...

Taking a SWAG at the Phil Irving chart, that fairing is probably worth about 8-9 hp...............that's aero drag power 8)

Where did you get your triple clamps - they look non-stock, maybe billet.
 
Dances with Shrapnel said:
An earlier version of this graph actually labels the actual graph lines. Through logic you can figure out that the top line is "C" with the corresponding legend "HEAVYWIEGHT MACHINES. From reading Phil Irvings text associated with this graph, it is not perfectly clear (to me at least) if the graph is indicating crankshaft power or only aero drag and rolling resistance power but the graph is certainly good enough to illustrate the significance of wind resistance power necessary to overcome at speed. The aero drag (wind resistance) power is proportional to the cube of the speed so one can use their imagination to visualize what it takes to go fast with these examples.

If the graph only depicts aero drag and rolling resistance power, then rear chain, gearbox and primary drive losses would need to be factored in. The additional losses usually amount to several percentage points of overall power. Phil Irving provides a nice simple example of the aero drag component in his text one page prior to this graph.
Click to expand...

Sorry about the labels. He does explain in the text that they go A, B, C, bottom to top.

Phil also states in the text that the curves are "compiled from a number of known performance figures", not from theoretical calculations. He specifically mentions that they "do not appear to rise so rapidly as might be expected with increase in speed, but this is because in the examples chosen greater efforts had been put into reducing wind resistance by streamlining, and rolling resistance, partly by reducing weight, and partly by using special tires." So it looks like he collected known data from certain bikes, and then fit the data to smooth curves.

His book is getting a little long in the tooth, and is written for the layman. Not a single integral equation to be seen. But it's got all the basics very well explained, and is still one of my favorite references.

Ken
 
this seems to be important, i think best sorted separate here to isolate from everything else 2c
needed-mph-and-100-mph-t25282.html
otherwise ends up too hard to even follow & lost on most, it could also go in the main commando forum if considered more appropriate

i googled "10 hp is needed to do 60 mph,and ~32 hp to do 100 mph" this site came up 2nd hit, that's about all there is

Dances with Shrapnel said:
Now Rohan, show us your two points on any single curve on that chart! The numbers I am referring to and have always referred to are quoted from you:

"it is commonly quoted that ~10 hp is needed to do 60 mph,and ~32 hp to do 100 mph."

Use a french curve to honor the shapes of the example curves if you want. So where does the 10 hp land, eh Rohan? It does not fit the curves. No. So where do the numbers come from? Citation and basis for numbers?

But this is beside the point as you were trying to reconcile the: "it is commonly quoted that ~10 hp is needed to do 60 mph, and ~32 hp to do 100 mph." with the general equations for power to overcome aero drag which is adequately explained in the Phil Irving Tuning for Speed. Furthermore, Phil Irving points out the example numbers (manifested in the curve that Ken was so kind to post) to begin to calculate total power required factoring in aero drag power as well as such things as rolling resistance and maybe more.

The "commonly quoted that ~10 hp is needed to do 60 mph, and ~32 hp to do 100 mph" numbers are not the aero drag numbers; this had been a source of this confusion on the part of Rohan. That is why I suggested reading up on what Phil Irving , Tuning for Speed presented. The rest has been a Rohan subterfuge to save face.
Click to expand...
 
Thanks Ken.

It is really more of a curiosity for point of clarification but what is not clear to me is exactly what power is being shown in the graphs. Is it crank HP, rear chain pull hp (aka wind + Rolling Resistance)?
 
Here is another curve illustrating power requirement from Sportbike Performance Handbook by Kevin Cameron. You can read the text on the data source so I don't suggest considering the graph gospel but it does illustrate the rolling resistance friction broken out as a more or less linear component separate from the aero drag component. The curve combines the rolling resistance and air drag. Another important concept being illustrated is surplus power for acceleration. :D
Commando motor in solid frame
 
Dances with Shrapnel said:
Thanks Ken.

It is really more of a curiosity for point of clarification but what is not clear to me is exactly what power is being shown in the graphs. Is it crank HP, rear chain pull hp (aka wind + Rolling Resistance)?
Click to expand...

I think, mostly from the calculation example he did on the previous page, and the words he used in talking about calculated compared to known values, that the chart uses crankshaft horsepower. But, as you noted, it's really not clear, so that is just my best guess.

Ken
 
Nice explanation by Kevin Cameron, as usual. I've seen similar explanations in "how to race a car" books, back when I dabbled in that a little, but I gave them all away to a son-in-law when he took up vintage car racing.

Ken
 
I came across that after reading your response to acotrel (Alan) in the "other" thread. I was looking for a chart that, if I recall correctly, plotted gear ranges against the torque curve. It showed a systematic approach to selecting the individual gear ratios if you have that luxury. It was a motorcycle reference and if I get a chance (more properly manage my time), I will dig it up and post it here or on that "other" thread.
 
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