In-Water, Real Time Thrus Measurement for FE Boats

[graill]

The current digital scale I am using reads to 11 lbs. The resolution is 1 gram. I checked the accuracy with known value weights and it is very, very good. By using the lead shot in the white cup to balance the weight of the motor I can get it within a few grams then just TARE it out. Thus the scale force represents the actual Thrust of the motor.

I agree with acceleration, boat set up, etc. However this test is ONLY to compare performance of submerged thrusters steady state output. The end result is for a new military underwater propulsion system. Small is key so I need to get the highest thrust...(that will eventurlly propell a diver hands-free)... with the max efficiency which, in this case amounts to the lowest watts consumed per pound of thrust.

This may not be directly applicable to predicting FE performance but it hopefully will show how thrust varies as various components such as motor, batteries, props, gear boxes, etc are changed. Hopefully I will have a chance to post some initial results today.

Dont let me pop your balloon, but,

Have you researched the *Hundreds of thousands* of underwater propulsion patents, also taking into account any classified patents or articles. These posted articles and results on exactly what your doing? Testing is fun but if your spinning your wheels covering old or new ground already claimed and documented...

Just me being curious.

[questtek]

Dont let me pop your balloon, but,

Have you researched the *Hundreds of thousands* of underwater propulsion patents, also taking into account any classified patents or articles. These posted articles and results on exactly what your doing? Testing is fun but if your spinning your wheels covering old or new ground already claimed and documented...

Just me being curious.

Don't worry, my balloon pops daily! I have indeed researched quite a bit since I have been in this field professionally for over 30 years. The project I am currently working on has mandated parameters by an Asian Navy, actually the equivalent of our SEAL team. There is a current FOREIGN patent pending on the project but it needs to be "Dialed IN" in terms of motor performance and optimization....and that's what I am attempting to do.

I did run a series of tests today, all on a Leopard 4074 motor, Seeaking 180 ESC and 4s LiPo. I ran tests with 7 different props. The first 5 props were 37 to 51 mm 2-bladed and the last two were 52 and 57 mm 3-bladed.

Depending on the prop and speed, I obtained thrusts of over 11 lbs at a bit over 1000 watts of input power. The RPM's for the test ran up to 20,000 for the smaller props and a little over 10,000 for the giant 3-bladed props.

I have all the data and summary plot on a detailed EXCEL spread sheet that even provides Thrust/1000RPM as well at Thrust/Watt. Just open the attached PDF file for all the data and summary graph
This is NOT at all the system that will be used in my current project however I did it to show the viability of such a test arrangement for the type of static tests I will conduct in the future. Again, in this application only, static testing is good since the diver will be propelled at only a few MPH and not 60 MPH FE-type speeds.

I will attach the spread sheet now as a PDF document....and look forward to comments from forum members on what it all means!

[graill]

Don't worry, my balloon pops daily! I have indeed researched quite a bit since I have been in this field professionally for over 30 years. The project I am currently working on has mandated parameters by an Asian Navy, actually the equivalent of our SEAL team. There is a current FOREIGN patent pending on the project but it needs to be "Dialed IN" in terms of motor performance and optimization....and that's what I am attempting to do.

I did run a series of tests today, all on a Leopard 4074 motor, Seeaking 180 ESC and 4s LiPo. I ran tests with 7 different props. The first 5 props were 37 to 51 mm 2-bladed and the last two were 52 and 57 mm 3-bladed.

Depending on the prop and speed, I obtained thrusts of over 11 lbs at a bit over 1000 watts of input power. The RPM's for the test ran up to 20,000 for the smaller props and a little over 10,000 for the giant 3-bladed props.

I have all the data and summary plot on a detailed EXCEL spread sheet that even provides Thrust/1000RPM as well at Thrust/Watt.

This is NOT at all the system that will be used in my current project however I did it to show the viability of such a test arrangement for the type of static tests I will conduct in the future. Again, in this application only, static testing is good since the diver will be propelled at only a few MPH and not 60 MPH FE-type speeds.

I will attach the spread sheet now as a PDF document....and look forward to comments from forum members on what it all means!

Coolness, good luck. Post some vids if possible if your project doesnt get too secret when your done whenever.

[Brushless55]

interesting!

[questtek]

interesting!

Any ideas of just how to interpret the data?

[Brushless55]

Any ideas of just how to interpret the data?

show the data and I'll give it a whirl

[questtek]

show the data and I'll give it a whirl

Just open the PDF file attached. It has all the data from the 7 test runs plus a summary graph. Sorry, looks like the summary graph did not convert in the PDF attachment format.

[questtek]

Here is a short video of the actual in-water Thrust testing of a Leopard 2200KV motor with the first of 7 different propellors. The ESC is a Seaking 180 and the power is a 4s, 5000 mAhr LiPo pac.

http://www.youtube.com/watch?v=OeEIbDarqYk&feature=youtube_gdata

[Make-a-Wake]

Keep 'em comin'........................is that the same leaf that keeps gettin' churned down, i'd pull it out......................lol

[FE Wannabe]

Joe,

For moving a diver through the water wouldn't lower RPM's with a big prop be more efficeint than high rpms with a small prop? It seems like there would be a lot more cavitation induced when you try to move a heavy object with a small prop at high RPM.
Just a thought.

By the way, if you flip that apparatus over and put a bowl just under the prop....IT's MARGARITA TIME!

Let me know if you need some help churning up the water over there, that lake looks too calm.
Keep up the good work, hope to see you soon.

Brad

[questtek]

Joe,

For moving a diver through the water wouldn't lower RPM's with a big prop be more efficeint than high rpms with a small prop? It seems like there would be a lot more cavitation induced when you try to move a heavy object with a small prop at high RPM.
Just a thought.

By the way, if you flip that apparatus over and put a bowl just under the prop....IT's MARGARITA TIME!

Let me know if you need some help churning up the water over there, that lake looks too calm.
Keep up the good work, hope to see you soon.

Brad

You are so correct, Brad. The Leopard was only the first motor to test. The nezxt one tested was one of the Castl Creation SALE outrunners at 220 KV. I put a giant 3-bladed prop on it. No cavitation and the thrust per watt was about 5 times that of the Leopard. For my specific application a low KV motor is essential. In act, I will be using this motor with a 10:1 kreduction gearbod to make it a 20KV motor running from a 10s lIpO PAC. Analysis shows I need 26 lbs of thrust to propell a fully dressed SCUBA diver underwater at a speed of 3.17 MPH.

I am now in Las Vegas at CES but will post more results from different motors when I return....and we will have a few "cavitation blended" drinks from my apparatus!

[H2OCamel]

In my best Spock voice..."fascinating Jim" cool stuff for shure