Bilge Pump Thrusters and Props...Questions, Questions!

Anything to do with Propulsion.
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stevetyphoon
Posts: 2
Joined: Sep 6th, 2016, 4:00 pm

Bilge Pump Thrusters and Props...Questions, Questions!

Post by stevetyphoon »

Hi Guys,
I've built a very basic ROV using waste pipe, some rebar for ballast and bilge pumps for thrusters, props from Hobbyking. The control system is using Arduinos and motor drivers for the pumps, the umbilical is just Cat5 cable.
Once completed and roughly ballasted to be neutrally bouyant I went on the maiden voyage....I was amazed at how fast it went forward, way too fast so had to reduce the speed in the code. So now fwd is nice and slow and manageable. Reverse is nice and slow.
My problem is going up and down. I can go down very quickly but coming up takes forever.
So previously knowing nothing about props, I just imagined they were symmetrical, I have learned that props are much better at 'pushing' thru the water than 'pulling'.
The only solution I can think of is to make the rov positively bouyant, which it should be, and it was until I added a GoPro, so can use the bouyancy to aid the props in coming 'up'. I would prefer to be pretty much neutrally bouyant so I don't have to keep applying down thrust to keep in position.
Is there anyone out there who can pass on some words of wisdom about props and perhaps suggest a way around this?
Thanks in advance for any help.
Cheers
Steve
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