Speedometer VS GPS
Thread Starter
Race Director
Joined: Feb 2005
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Speedometer VS GPS
Went out this morning checking speedo's against my Magellan GPS 2000 XL....
At 70 MPH on speedo, the 78 was most accurate at 68.9 MPH...
At 70 MPH on speedo, the 69 was slow at 65.4 MPH...at 80 on speedo,GPS speed was 72.6.....
Ran at steady speed for 6 miles....
At 70 MPH on speedo, the 78 was most accurate at 68.9 MPH...
At 70 MPH on speedo, the 69 was slow at 65.4 MPH...at 80 on speedo,GPS speed was 72.6.....
Ran at steady speed for 6 miles....
Melting Slicks
Joined: Aug 2005
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This subject always creates a big bru-ha-ha over on the offshore powerboat forum. Those guys will spend THOUSANDS to get another 3 ~ 5mph.
So...when someone claims they did such-and-such mod and gained 2mph, there's always one who asks "GPS or radar?". I guess they believe the GPS isn't accurate enough to prove a speed gain.
So...when someone claims they did such-and-such mod and gained 2mph, there's always one who asks "GPS or radar?". I guess they believe the GPS isn't accurate enough to prove a speed gain.
Thread Starter
Race Director
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Originally Posted by TonySinclair
This subject always creates a big bru-ha-ha over on the offshore powerboat forum. Those guys will spend THOUSANDS to get another 3 ~ 5mph.
So...when someone claims they did such-and-such mod and gained 2mph, there's always one who asks "GPS or radar?". I guess they believe the GPS isn't accurate enough to prove a speed gain.
So...when someone claims they did such-and-such mod and gained 2mph, there's always one who asks "GPS or radar?". I guess they believe the GPS isn't accurate enough to prove a speed gain.
Melting Slicks
Joined: Aug 2005
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Originally Posted by rihwoods
Those boat guys need a fixed receiver to check the roving one...if they want to be **** on...
My boat tops out at 65mph (+/-), and I'll be damned if I spend one thin dime trying to hit 66. You'll find me at Shooter's ogling the bikini girls while the mini-weenie guys are out battling over a few mph...
Thread Starter
Race Director
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Originally Posted by TonySinclair
We will run between fixed buoys, one mile apart, with a stop-watch, or during the organized runs, someone will bring along a radar gun.
My boat tops out at 65mph (+/-), and I'll be damned if I spend one thin dime trying to hit 66. You'll find me at Shooter's ogling the bikini girls while the mini-weenie guys are out battling over a few mph...
My boat tops out at 65mph (+/-), and I'll be damned if I spend one thin dime trying to hit 66. You'll find me at Shooter's ogling the bikini girls while the mini-weenie guys are out battling over a few mph...
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GPS....
Race Director
Joined: Feb 1999
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From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
Originally Posted by TonySinclair
This subject always creates a big bru-ha-ha over on the offshore powerboat forum. Those guys will spend THOUSANDS to get another 3 ~ 5mph.
So...when someone claims they did such-and-such mod and gained 2mph, there's always one who asks "GPS or radar?". I guess they believe the GPS isn't accurate enough to prove a speed gain.
So...when someone claims they did such-and-such mod and gained 2mph, there's always one who asks "GPS or radar?". I guess they believe the GPS isn't accurate enough to prove a speed gain.
Is that Gallons Per Second in offshore boat racing???
Drifting
Joined: May 2005
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From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
Are we talkin mach numbers here ? 
At work I cruise at .80 mach for the optimum fuel burn / true airspeed / ground speed. The higher I climb...the lower the fuel flow and the higher the mach number. The GPS sattelite does all the climb and decent planning based on a 4 degree slope and tells me when to stop climb and when to start down. The longer I stay above 35,000 ft...the less fuel I burn and the faster I get from a to b. None of it makes any sense to me, but it's a SMACK of fun..... I have no idea how any of it works ! 
At work I cruise at .80 mach for the optimum fuel burn / true airspeed / ground speed. The higher I climb...the lower the fuel flow and the higher the mach number. The GPS sattelite does all the climb and decent planning based on a 4 degree slope and tells me when to stop climb and when to start down. The longer I stay above 35,000 ft...the less fuel I burn and the faster I get from a to b. None of it makes any sense to me, but it's a SMACK of fun..... I have no idea how any of it works !
Melting Slicks
Joined: Aug 2005
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Originally Posted by Eddie 70
Is that Gallons Per Second in offshore boat racing???
Just imagine your mpg as a negative number...
Last edited by TonySinclair; Dec 11, 2005 at 10:23 PM.
Melting Slicks
Joined: Aug 2005
Posts: 2,606
Likes: 5
Originally Posted by fotyfobravo
At work I cruise at .80 mach for the optimum fuel burn / true airspeed / ground speed.
That's about how fast people drive here on the freeway during rush hour...
