Member Contributer CornerCarver Posted July 26, 2016 Member Contributer Share Posted July 26, 2016 1 hour ago, Skids said: The trouble with GPS & lights are that they can only measure average speed over a certain distance; they don't measure absolute speed. I guess the only way to measure absolute speed is with a calibrated radar gun. With a radar gun you would have to be the only thing in it's field of view. Radar does not find the fastest object but (as you know Skids) returns the instantaneous speed of the largest objects' radar return signal. Link to comment Share on other sites More sharing options...
lshark Posted July 26, 2016 Share Posted July 26, 2016 i wonder if veefour had his cruise control on ??? Link to comment Share on other sites More sharing options...
Member Contributer Skids Posted July 27, 2016 Member Contributer Share Posted July 27, 2016 11 hours ago, CornerCarver said: With a radar gun you would have to be the only thing in it's field of view. Radar does not find the fastest object but (as you know Skids) returns the instantaneous speed of the largest objects' radar return signal. Yes, but you can focus the beam and with Pulse Doppler, it measures relative speed of any object it can see so a moving bike would stand out from any other returns. In theory at least it should be more accurate than an average speed, almost irrespective of how short that average speed was measured over (can't remember how to calculate it for GPS and can't be arsed Googling it). Link to comment Share on other sites More sharing options...
Member Contributer JZH Posted July 27, 2016 Member Contributer Share Posted July 27, 2016 But if your goal is to verify a record "top speed", then an average speed would be fine, because it can never be more than the top speed. Ciao, Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted July 27, 2016 Share Posted July 27, 2016 What about the need to go one direction and then the opposite direction, then average the two runs, to get an official top speed, as averaging the two runs in opposite directions would cancel out the effects of any possible head/tail wind. Link to comment Share on other sites More sharing options...
Member Contributer Skids Posted July 27, 2016 Member Contributer Share Posted July 27, 2016 Absolutely. As I said, the lights & GPS only give you an average speed over a certain distance, and that is what is required for official records. I was just pointing out that it doesn't actually give you the true fastest speed. Link to comment Share on other sites More sharing options...
Member Contributer CornerCarver Posted July 27, 2016 Member Contributer Share Posted July 27, 2016 3 hours ago, CandyRedRC46 said: What about the need to go one direction and then the opposite direction, then average the two runs, to get an official top speed, as averaging the two runs in opposite directions would cancel out the effects of any possible head/tail wind. This is necessary when the wind is above a certain mph IIRC.... 7 minutes ago, Skids said: Absolutely. As I said, the lights & GPS only give you an average speed over a certain distance, and that is what is required for official records. I was just pointing out that it doesn't actually give you the true fastest speed. Still we are splitting extremely fine hairs 5 ways to think that the average speed across a distance of only 60 feet would have much variance when you are travelling over 260 feet each second. Link to comment Share on other sites More sharing options...
Member Contributer Skids Posted July 27, 2016 Member Contributer Share Posted July 27, 2016 4 minutes ago, CornerCarver said: This is necessary when the wind is above a certain mph IIRC.... Still we are splitting extremely fine hairs 5 ways to think that the average speed across a distance of only 60 feet would have much variance when you are travelling over 260 feet each second. But it's attention to detail like that which wins you the record! Link to comment Share on other sites More sharing options...
crakerjac Posted July 27, 2016 Share Posted July 27, 2016 Link to comment Share on other sites More sharing options...
Member Contributer CornerCarver Posted July 28, 2016 Member Contributer Share Posted July 28, 2016 "'Cause this is THRILLER!...Thriller night....." Link to comment Share on other sites More sharing options...
Member Contributer Skids Posted July 29, 2016 Member Contributer Share Posted July 29, 2016 On 26/07/2016 at 4:56 PM, CandyRedRC46 said: Now wouldn't that just shrink that certain distance? Can you ever really measure absolute speed? Indeed. At what point does a measurement of speed over distance become impossible? Link to comment Share on other sites More sharing options...
The Phantom Posted July 29, 2016 Share Posted July 29, 2016 Of course we are also taking planetary rotation into account here, right? The difference between groundspeed and planetary rotation will have to be adjusted according to the actual direction of the track, a simple east-west layout would be fine and require no further adjustment but anything else will have to be correctly juxtaposed against the measurements between the Cartesian co-ordinates... I recommend six-figure grid references, seeing as it's a world record we're talking about. Link to comment Share on other sites More sharing options...
Member Contributer EhViffer Posted July 29, 2016 Member Contributer Share Posted July 29, 2016 We are truly in the weeds now on the motorcycle shaft drive world speed record. My shaft drive VFR is so powerful I'm going to time travel backward to when this thread first started and not read it, thus the time I spent reading it will not have happened. Link to comment Share on other sites More sharing options...
Member Contributer Skids Posted July 29, 2016 Member Contributer Share Posted July 29, 2016 2 hours ago, The Phantom said: Of course we are also taking planetary rotation into account here, right? The difference between groundspeed and planetary rotation will have to be adjusted according to the actual direction of the track, a simple east-west layout would be fine and require no further adjustment but anything else will have to be correctly juxtaposed against the measurements between the Cartesian co-ordinates... I recommend six-figure grid references, seeing as it's a world record we're talking about. Should absolute top speed be measured relative to a motionless point in space? 6-figure top speed! Awesome. Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted July 29, 2016 Member Contributer Share Posted July 29, 2016 4 hours ago, The Phantom said: Of course we are also taking planetary rotation into account here, right? The difference between groundspeed and planetary rotation will have to be adjusted according to the actual direction of the track, a simple east-west layout would be fine and require no further adjustment but anything else will have to be correctly juxtaposed against the measurements between the Cartesian co-ordinates... I recommend six-figure grid references, seeing as it's a world record we're talking about. I go for 8 digit grid & remember to specify the map scale, as 6 digits ont 1:600000 is not very accurate :) That said is you do an east west run, then the variables are the same for everyone, so pointless. Link to comment Share on other sites More sharing options...
Member Contributer Rider14 Posted August 1, 2016 Member Contributer Share Posted August 1, 2016 So did the OP have a steering damper or not? Curious... If not, what ever happened to the guy that was fabricating one for his speed test? - Dan Link to comment Share on other sites More sharing options...
dynajohn Posted August 1, 2016 Share Posted August 1, 2016 On 7/27/2016 at 1:09 PM, CornerCarver said: This is necessary when the wind is above a certain mph IIRC.... Still we are splitting extremely fine hairs 5 ways to think that the average speed across a distance of only 60 feet would have much variance when you are travelling over 260 feet each second. Indeed it is splitting extremely fine hairs in the case of questioning the accuracy of VFR's documented top speed at Loring if that is the intent of anyone here. The speed is measured over 60 feet at the 1.5 marker. This motorcycle was drag and HP limited at this speed. He was probably very close to his recorded top speed 800 ft. before the 1.5 mile marker. This track does not have the facility for making two way runs like the salt flats so arguing over whether his recorded top speed is valid or not is not relevant in this case. It is valid for this track and online at the Loring site for anyone who wants to look it up. Whether you think VFR's time and effort over two summers was wasted in pursuing this endeavor all I can say is opinions differ. I personally congratulate and thank him for sharing the story over his two seasons of racing at Loring. Link to comment Share on other sites More sharing options...
Member Contributer CornerCarver Posted August 2, 2016 Member Contributer Share Posted August 2, 2016 8 hours ago, dynajohn said: Indeed you are splitting extremely fine hairs in the case of questioning the accuracy of VFR's documented top speed at Loring if that is the intent here. The speed is measured over 60 feet at the 1.5 marker. This motorcycle was drag and HP limited at this speed. He was probably very close to his recorded top speed 800 ft. before the 1.5 mile marker. This track does not have the facility for making two way runs like the salt flats so arguing over whether his recorded top speed is valid or not is not relevant in this case. It is valid for this track and online at the Loring site for anyone who wants to look it up. Whether you think VFR's time and effort over two summers was wasted in pursuing this endeavor all I can say is opinions differ. I personally congratulate and thank him for sharing the story over his two seasons of racing at Loring. That is not my intent, if that is what you infer from reading this thread then please re-read it. Agreed 100%. Link to comment Share on other sites More sharing options...
Member Contributer Skids Posted August 2, 2016 Member Contributer Share Posted August 2, 2016 1 hour ago, CornerCarver said: That is not my intent, if that is what you infer from reading this thread then please re-read it. Agreed 100%. Absolutely. Link to comment Share on other sites More sharing options...
dynajohn Posted August 2, 2016 Share Posted August 2, 2016 I was not questioning your intent CornerCarver I was actually agreeing with you but I can see re-reading my post why you thought I did. Re-read edited post and you have my apology for not being more careful. Link to comment Share on other sites More sharing options...
cbblr Posted February 1, 2017 Share Posted February 1, 2017 I hope you guys realize that you can have a difference in rear tire diameters due to tire manufacturer variations, which would of course change your gear ratio, and therefore your top speed. If you want to go a bit faster, get a larger diameter rear tire. Chris Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted February 1, 2017 Share Posted February 1, 2017 11 hours ago, cbblr said: I hope you guys realize that you can have a difference in rear tire diameters due to tire manufacturer variations, which would of course change your gear ratio, and therefore your top speed. If you want to go a bit faster, get a larger diameter rear tire. Chris Got to love those thread resurrection first posts... ~read drag and hp limited~ Link to comment Share on other sites More sharing options...
andy Posted February 1, 2017 Share Posted February 1, 2017 Love seeing that my VFR could get to 175+, but it'll have to do it vicariously because it's rider would fall off even a full throttle 3rd gear roll on! Link to comment Share on other sites More sharing options...
cbblr Posted February 1, 2017 Share Posted February 1, 2017 Gotta start someplace! LOL Chris Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.