Angle of Newton Power Meter

Angle of Newton Power Meter

Postby cheoherrera » Tue May 16, 2017 5:06 pm

Hi,

i use the old school Newton Power Meter for my TT Bike. i havent used a remote wind sensor as i have the PM set up in the middle of my aerobars and i dont use any hydration systems in the aerobars.

i raced Ironman 70.3 Gulf Coast on saturday, and my readings were off the chart, i had an avg watts of 365W, NP: 379W. this sounds crazy... could it have something to do with the angle of the PM and they way is set up?

i have added two pictures of my set up and the ride file of my last race (saturday at Panama City Beach 70.3)

Thanks
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cheoherrera
 
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Re: Angle of Newton Power Meter

Postby Velocomp » Tue May 16, 2017 5:17 pm

1) Your wind scaling was a bit high. I fixed this with the "Analyze Route" command

2) Your CdA is way too high for a TT bike. For a person your weight (and presumed size of around 5' 9"), your TT CdA should be around 0.25. I fixed this, too.

With these changes your watts drop to a much more believable 230W...still excellent!

Modified ride file and profile attached.
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Re: Angle of Newton Power Meter

Postby cheoherrera » Tue May 16, 2017 6:37 pm

thanks!

i have uploaded the new profile to my PM. is there anything i should do besides this to improve accuracy?
cheoherrera
 
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Re: Angle of Newton Power Meter

Postby Velocomp » Tue May 16, 2017 7:41 pm

Post your next ride file on this thread
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Re: Angle of Newton Power Meter

Postby cheoherrera » Wed May 17, 2017 6:23 pm

here you go! easy 18mile recovery ride this morning (but bery windy)... i used the profile as modified by you

Thanks!
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Re: Angle of Newton Power Meter

Postby Velocomp » Wed May 17, 2017 6:47 pm

This looks much better!
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