Gps

[Gray Fox]

Hey guys what make and modle GPS are you using when prop testing?

[blueskyracer]

Garmin E-Trex

[B Walker]

I see alot of Garmin E-Trex models used. They are cheap and easy to use.

I prefer the "Legend H" model which is the blue one and available @ Wal Mart for 149.99. If your on a budget the "H" model (yellow one) is 99.99 and almost as good.

Heres a list of features you may find useful:

Waterproof
12 channel differential
measures in tenths of a MPH
has a memory for highest speed attained

good luck
Brad Walker

[blueskyracer]

Would like to add that if you watch you can get good deals like we did by using E Bay

[Gray Fox]

Thanks Brad and Mike will check out those models and check out ebay also. I think I have seen a few yellow ones in boats around here. Thanks for the help.
Joel
R-38

[B Walker]

try Amazon too

BW

[Graham 18ce]

Magellan Explorist 500 - is my current gps...
I'll be going back to a Keller water pickup this summer if i actually have time to do real testing. GPS is great for racing for me, testing, i'd rather have water pickup.

[B Walker]

I know what your trying to say......

But no water pickup speedo will read in tenths of a MPH.

What your talking about is lap times and I 100% agree.

Lets talk about real time telemetry. I know there are a few racers doing it already.....

http://en.wikipedia.org/wiki/Telemetry

BW

PS I was once told a racer is only as good as his tools.....or maybe it was the singular, cant remember....

PPS When your doing something and nobody else understands what your doing, your either in left field or on a different level. Usually only time can tell the difference.

[Graham 18ce]

I agree, water pickup is only good for a 1/4 to 1/2. but it is always the same water speed reading. GPS being land speed and so on, tenths really don't add up in my book. current speed is going to be effected in that indication.
we have a data logger which we can race with, not gps, not the pickup tube...used it a number of years ago to get us going in the right direction and setup,with all the changes i've made over the last two years, boats, motors, and now all the prop work i have, it is time to pull it out again.

[Dave M]

Suggestion

Water pickup is a great way to go and can be used to 1/2MPH or so if used right. If you are chasing a 1/10th of a mile an hour, you need to get out more often.

Go to your local plumbing supply company and purcahse a boiler pressure guage of your choice. Costs from around 10 buck to 100 bucks depending on your wants. I think th eone I used to use was around 30 bucks. Connect this to your water pickup and you have your speedo. It won't tell you the MPH, but it will tell you water pressure and all you really are doing with a speedo is what prop is faster anyway. Cheap way to do it. If you want fancy, install a valve that will make the pressure guage hold at the highest PSI. Then all you have to do is go out hold the throttle on and come in and then look.

If you want a GPS as the thread indicated, I use the Etrek cheapy as well. It picks up as good as the $300 one I ruined getting wet once.

[ZUL8TR]

pressure gage

Water pickup is a great way to go and can be used to 1/2MPH or so if used right. If you are chasing a 1/10th of a mile an hour, you need to get out more often.

Go to your local plumbing supply company and purcahse a boiler pressure guage of your choice. Costs from around 10 buck to 100 bucks depending on your wants. I think th eone I used to use was around 30 bucks. Connect this to your water pickup and you have your speedo. It won't tell you the MPH, but it will tell you water pressure and all you really are doing with a speedo is what prop is faster anyway. Cheap way to do it. If you want fancy, install a valve that will make the pressure guage hold at the highest PSI. Then all you have to do is go out hold the throttle on and come in and then look.

If you want a GPS as the thread indicated, I use the Etrek cheapy as well. It picks up as good as the $300 one I ruined getting wet once.

-----------------------------------

For those who want to convert the pressure gage reading to MPH use this fairly close conversion for speedo head or pressure gage not more than about a 12" above the water:

V (mph) = 8.312 x (squre root of gage pressure)

examples: pressure of 50 psi = 58.8 mph
70 psi = 69.5 mph
90 psi = 78.9 mph
110psi = 87.2 mph

Another pickup approach:

Instead of the water pickup at the transom which robs speed I used a special the turning fin with a small 1/8" tube down the rear edge of the fin with the tube bent forward about 5/8" and 1/2" under the fin tip. This setup is more accurate than the rear pickup since the water to the pickup is not disturbed by the rear planing surface and the fin pickup is not disturbed by the fin and sponson water if the hydro is set up right and sponsons are clear of the water.

[seanp3]

How much drag do the water pickup's add? Can they slow you down?

[Trihedral_1]

For the guy that has everything, there's a mini airspeed indicator from a place called Eagletree. They're cheap and they look really cool.
Better yet, they have a new ap for iPhone that takes video with realtime speed and g-force (called Cockpit Recorder for iPhone).

Real world we use a Garmin 201.

Jimi O. (305-R)

[sam]

For $2.99 its very tempting

[Trihedral_1]

For $2.99 its very tempting

yeah. For $2.99 think of the fun. We're gonna mount it on my 8yr old's bike.

Jimi O. (305-R)