Eagle tree calibration?

[ken turmon]

I am trying to calibrate my data logger to use for hi amp readings. I hooked it up in my boat and ran it on the bench for a couple minutes. I used a clamp on meter to get an amp reading but the reading on the meter fluctuates so much its impossible to get a true reading. Is there a way to get a reading through it that is a stable load, without having to solder 40 bulbs together...??? <_<

 

[hugh hargett]

If you have a airplane propeller get your motor and a piece of L stock and make a fixture to hold you motor and you airplane propeller. The fire it up and try. The airplane propeller will give you a fairly contant load at a constant speed and cool the motor at the same time so you may be able to run it for an extended period if need be.

 

[Jim Caldwell]

The Prop will work, WATCH the RPM's I had 1/2 of an 8/4 prop disappear through my garage ceiling.

20,000 is about the limit on them.

Low rpm motor handy??

 

[MarkTanski]

Ken I've got a couple air props around here, if you can figure out how to mount one you can try it, Maybe use one of my 4s setups to drop the rpm at bit.

No idea what size would be best, think I've got a couple 9 and 10 inchers left.

Might need a cheap prop adapter from Lakefield.

Back to the boonies in a while, great music festival. We put on one of our best shows last night, what a hoot. Nice when they are close enough to home so I don't have to camp in a cow field packed full of hippies with questionable personal hygiene habits! PLaying again at 2 this afternoon.

Not quite my scene, lol was mixing Vodka martinis on the tailgate of my truck, martini glass, shaker and all. All these people rolling around in the dirt and I bring a carpet and a chaise lounge to set up on for the day. Urban southern boy tailgating!

Shoot me a e-mail asap and I can get that prop to you this morning (before 11) or I can drop it off tomorrow morning. Just found a 9x7 and think I have a 10x6 maybe in the garage or basement.

 

[hugh hargett]

If you cant get up with Mark you can get you a prop nut for the motor off ebay and a .21/40 sized prop.

 

[hugh hargett]

Jim you really should post your entire method here and the mods should pin it. It will be a good how to tool In my opinion.We could have a tips and trick section pinned here as well like "loading" an fe motor etc. It will make it alot easier on fellow boaters that want to come play FE with us.

 

[ken turmon]

Yes all such info is very useful. I can already see that this ET is going to be the cats ass. I just need a good reliable way to get an amp reading.

 

[hugh hargett]

The eagle tree has some very nice things going on there may even be some type of telemetry add on :blink: . Youll thank yourself for building the make shift air dyno and buying the eagle tree later. B) .JIM MAKE SURE YOUR AIRPLANE PROP IS BALANCED :wacko: . Just use throttle trim only to make speed adjustments and a hold.

 

[Jim Caldwell]

I quit using the props years ago, too Dangerous!!!!

Ducted Fan maybe if you want to go this route.

Light bulbs are the safeest and you can use them to bring packs down to storage voltage.

 

[ken turmon]

Yes I see what you mean. I built a dyno for calibrating and testing. A 1717 with an air prop is just plain terifying. I could'nt get past the 1 amp mark without soiling myself. In the end I made up some jumpers and hooked it to my charger with the charger being the battery and the lipo pack being the esc. I set it to 7 amps and let it run for a couple minutes and then calibrated my ET to that. Hopefully that will get me close enough. I'll save the dyno for testing new esc's etc. :blink:

 

[MarkTanski]

Or try a 2s pack to keep the tip rpm down on the prop, amp draw would go up but I'd imagine it would still be within reason. A 1600kv motor would only be doing a little over 13000 rpm on a 2s pack, thats well within reason. Not sure what Kv you've got, can't remember.

 

[ken turmon]

I played around with the numbers. I was able to get it calibrated to within .5 amps and .1 volts. Me likey...

 

[MarkTanski]

Cool! Want to do a mid week rip down the road from my place? Give it a test!

Oh ya LOL I bought a Whiplash 20 kit this morning! Not sure what came over me except the kit is in Canada and the shipping will be cheaper.

Going to shelf it until winter, decide how to power it then.

 

[hugh hargett]

Sounds grand!Ken :wub: Mark theres a castle 1520 on rr for sale for that p boat

 

[ken turmon]

Dam I wish I had known that . I could have used that to replace the 4074 i smoked. Oh well a scorpion 3226 will push it along just fine.