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Norton Commando Land Speed racer update

Classic Norton Commando Motorcycles.

Re: Norton Commando Land Speed racer update

Postby SteveA » Mon Sep 11, 2017 3:31 am

I spent 8 years working within 30' of Aermacchi's wind tunnel in Venegono, I even used the workshop in the basement a few times!

Cagiva on the other hand developed the aerodynamics of their 2 stroke GP bike in it. Several cycling projects used it.

You did need good scale models though!

Missed opportunities I guess.

Peter Williams spent many hours in the wind tunnel practicing and perfecting his tuck! Nearly getting frost bitten for his troubles if I recall!

Don't think they ever got Croxford in it, wonder how their speeds on the Sulby Straight compared? The figures must be around.
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Re: Norton Commando Land Speed racer update

Postby jseng1 » Wed Sep 13, 2017 2:58 pm

Seems like this is the fastest officially recorded speed for an unstreamlined Naturally aspirated Norton (149mph+).

Here's an example of what Herb has done for Andy's racer. The valve pockets are spread way out for the 44mm intake valves. Its an 81mm piston and you can see where the pockets have been moved all the way to the outside edge. He also gives a little more room between the valves to prevent hookup with the big cam they're using.

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Re: Norton Commando Land Speed racer update

Postby acotrel » Thu Sep 14, 2017 12:08 am

There is a handle-bar fairing a few guys use in Australia. It comes out and shields the hands. I've wondered if it give any measurable advantage. With aerodynamics there is a very big difference between riding a faired bike at speed compared with unfaired. You notice it most when you shut the throttle - the bike rolls faster and further than normal. On a race circuit, it does not matter much - you do one lap and you know what is happening. But when I was a kid, I fitted fairing to my road bike which I used to ride at highly illegal speeds. You don't stop where you think you are going to stop. With my old British bike,the difference at !00MPH seemed to be about 5 MPH increase with the fairing fitted.

Have you seen this video ? Perhaps top speed is slower if you rev the motor beyond max. torque ? When I race , I try to use close ratios to ride the top of the torque curve, that seems to give fastest acceleration, but I don't know what it does to top speed. Perhaps the difference when you try to go beyond max. torque towards max. horsepower is cancelled out by the exponential increase in wind resistance ?
https://www.youtube.com/watch?v=fgLNO3ThGD4
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Re: Norton Commando Land Speed racer update

Postby Fast Eddie » Thu Sep 14, 2017 1:22 am

When I was younger and even stupider than I am today, I had a GSXR 750 and my mates all had tings of a similar ilk.

I did some testing one day, on a closed private road of course, not on the M1 at all, and just folding in the fairing mounted mirrors gave a 5 mph increase in top end, as measured by the Suzuki speedo at least.

It's an exponential thing though. Taking the mirrors off of my Honda SS50 when I was 16 certainly did NOT give that another 5mph !!
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Re: Norton Commando Land Speed racer update

Postby acotrel » Thu Sep 14, 2017 1:49 pm

If I had a GSXR 750, I'd put MORE mirrors on it.
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Re: Norton Commando Land Speed racer update

Postby gripper » Sat Sep 16, 2017 2:50 am

Getting off an unfaired Commando and onto a Interpol 2 ex police bike with almost no engine braking tested my brakes to the limit and my underwear. The fairing was history pretty quickly as it weighed about 25Lb. My later Commander was deceptive. For a 588cc bike what seemed like 80 was often 95+ (Brilliant fairing)

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Re: Norton Commando Land Speed racer update

Postby acotrel » Sat Sep 16, 2017 12:34 pm

What are the rules for this land speed record class ? Are fairings and methanol permitted ? It not something I have ever done or probably would ever do, with a Norton. When my motor revs high for long periods, I get nervous.
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Re: Norton Commando Land Speed racer update

Postby lcrken » Sun Sep 17, 2017 2:52 pm

acotrel wrote:What are the rules for this land speed record class ? Are fairings and methanol permitted ? It not something I have ever done or probably would ever do, with a Norton. When my motor revs high for long periods, I get nervous.


The essence of the 1000 M-PG is 1000 cc limit, modified production chassis (details in rule books), pushrod engine, running on gasoline. Lots more specific rules for construction, safety, etc., in the rule books. So, no methanol. To run methanol you'd have to run in the M-PF class, modified, pushrod, fuel. No streamlining allowed. For that, you'd be in the MPS-PG class, modified partially streamlined, pushrod, gas (or MPS-PF for fuel).

If you want more detail, take a look at the AMA rule book for landspeed racing here

https://bonnevillespeedtrials.com/wp-co ... R-14-1.pdf

I'm not sure what exact rules they run at this track, but they are probably pretty similar to AMA or SCTA, so the above link should give you a good idea of what is involved in competing. All the AMA records are listed at the end of the rule book, and that makes some good reading too.

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Re: Norton Commando Land Speed racer update

Postby acotrel » Tue Sep 19, 2017 2:30 pm

It makes sense to run the class with no methanol or fairings. But without them, you probably hit a wall at a lower speed. The actual size of the record speed is probably irrelevant to the competition anyway. But it is interesting. If you were using a 6 speed close box, you might be better able to keep the engine revving near max torque. I was watching a video yesterday in which it was claimed that changing gear at maximum horsepower gives the fastest acceleration - not changing up at max. torque, but it makes we wonder if wind resistance stops you from going from the revs at which max torque occurs up to where max. horsepower occurs.
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Re: Norton Commando Land Speed racer update

Postby Eldo » Tue Sep 19, 2017 3:34 pm

acotrel wrote:It makes sense to run the class with no methanol or fairings. But without them, you probably hit a wall at a lower speed. The actual size of the record speed is probably irrelevant to the competition anyway. But it is interesting. If you were using a 6 speed close box, you might be better able to keep the engine revving near max torque. I was watching a video yesterday in which it was claimed that changing gear at maximum horsepower gives the fastest acceleration - not changing up at max. torque, but it makes we wonder if wind resistance stops you from going from the revs at which max torque occurs up to where max. horsepower occurs.


The current record (156.2mph) was set by a de-stroked Buell XB12; a 1200cc bike, destroked to 1000cc. It has a 88.9mm bore, which gives it a substantial valve size advantage. We're happy with our power, but I believe I am the limiting factor (my size vs the wind...) so we will look to gain any aero advantage we can. (Even maybe shave my beard...)

I know of a 6 speed Quaife for sale that will fit in a Norton, but it is pretty pricey and will likely come after we've exhausted more "financially responsible" options, like modifying the tank (so my helmet fits down in it), repositioning the tach, brake M/C, cable and wires and such. Herb has already shaved the starter nut down to fit inside the primary.) We may even narrow the frame at the seat so my knees tuck in better. (We will also pray for a tail wind come spring!)
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Re: Norton Commando Land Speed racer update

Postby lcrken » Wed Sep 20, 2017 9:09 am

It's a little surprising how much difference small aerodynamic changes can make in an un-faired bike, particularly when you get up into the 150 mph range. I recall some advice from an old-timer with several speed records when I was first starting at El Mirage. He said making sure you had your toes pointed straight forward instead of hanging down to catch the air made a measureable difference in top speed. This was on a bike with a conventional riding position, and wouldn't be possible in one of the stretched out riding positions on highly modified bikes.

My biggest limitation was not being able to bend my neck enough (arthiritis) to get into a really good tuck and still see ahead. I was complaining to one of the other (much younger) racers, and he said he had improved his ability to tuck in well by doing regular stretching exercises on his neck. Unfortunately, that didn't seem to help me regain lost flexibility. Maybe I need some glasses with prisms to let me look down and see straight ahead. :lol:

The point of all this is that all the small things you are working on are worth the effort. At some point in looking for more speed, the improvements are going to only come in small increments, but those increments add up.

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Re: Norton Commando Land Speed racer update

Postby Eldo » Wed Sep 20, 2017 9:22 am

lcrken wrote:It's a little surprising how much difference small aerodynamic changes can make in an un-faired bike, particularly when you get up into the 150 mph range. I recall some advice from an old-timer with several speed records when I was first starting at El Mirage. He said making sure you had your toes pointed straight forward instead of hanging down to catch the air made a measureable difference in top speed. This was on a bike with a conventional riding position, and wouldn't be possible in one of the stretched out riding positions on highly modified bikes.

My biggest limitation was not being able to bend my neck enough (arthiritis) to get into a really good tuck and still see ahead. I was complaining to one of the other (much younger) racers, and he said he had improved his ability to tuck in well by doing regular stretching exercises on his neck. Unfortunately, that didn't seem to help me regain lost flexibility. Maybe I need some glasses with prisms to let me look down and see straight ahead. :lol:

The point of all this is that all the small things you are working on are worth the effort. At some point in looking for more speed, the improvements are going to only come in small increments, but those increments add up.

Ken


We gained and additional 2.5mph between the 1 and the 1.5 by just pointing my toes straight back rather than leave them on the footpegs as I had been doing in previous runs!
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Re: Norton Commando Land Speed racer update

Postby Dances with Shrapnel » Wed Sep 20, 2017 10:39 am

I was not going to wait around for someone else to post this.

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Re: Norton Commando Land Speed racer update

Postby acotrel » Wed Sep 20, 2017 1:27 pm

A 6 speed close ratio box might not do much more for you than a 4 speed close ratio box. The difference with the 4 speed box is the lurch as you start to move, but once you are mobile and the motor is revving hard that becomes irrelevant It depends on how long the run up to the speed trap is. A close set of 4 speed gears can be had for about $600.
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Re: Norton Commando Land Speed racer update

Postby Dances with Shrapnel » Wed Sep 20, 2017 2:34 pm

Don't be foolish. Go with a six speed for your land speed record endeavors. PM me as I just removed a TTI six speed from my long stroke Norton Seeley and may part with it.


From the TT Industries web site.


6 Speed Heavy Duty Gearbox

Gear Ratios offered :
1st 2nd 3rd 4th 5th 6th
Low Ratio
2.44 : 1 1.755 : 1 1.418 : 1 1.243 : 1 1.1 : 1 1 : 1
Standard Ratio
2.294 : 1 1.755 : 1 1.418 : 1 1.243 : 1 1.1 : 1 1 : 1
Close Ratio
2.167 : 1 1.69 : 1 1.418 : 1 1.243 : 1 1.1 : 1 1 : 1
2.09 : 1 1.69 : 1 1.418 : 1 1.243 : 1 1.1 : 1 1 : 1

http://www.ttindustries.com/6_speed_gearbox.html

versus

4 Speed Heavy Duty Gearbox

Gear Ratios offered :
1st 2nd 3rd 4th
Low Ratio
2.178 : 1 1.46 : 1 1.176 : 1 1 : 1
Standard Ratio
1.96 : 1 1.46 : 1 1.176 : 1 1 : 1
Close Ratio
1.89 : 1 1.4 : 1 1.13 : 1 1 : 1
Moto Cross Ratio
1.89 : 1 1.52 : 1 1.237 : 1 1 : 1

http://www.ttindustries.com/4_speed_gearbox_hd.html
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