Hi Stratus,
I haven't completed my sub yet, but went about
sizing the motors by looking
at other subs of similar size & what motors
they had, & estimating from that what my need would be.
3 knots kept coming up in my searches as
a reasonable top speed for a personal submersible.
Double the speed underwater & you quadruple
your power output.
I believe I've heard of people making scale models
of their sub & pulling them through the water at their
intended maximum speed with a line attached to
something like fishing scales.
I am not sure whether there is a direct correlation
to the scaling up of the model & the force required to
pull it at a given speed. i.e.. if your model has a
1 liter displacement & takes 100 grams force to pull it at
3 knots does this mean that if your sub is 1000
liters displacement it will take 100 kilos of force to push
it at the same speed. Someone smarter than me might
want to comment.
Regards Alan
----- Original Message -----
Sent: Wednesday, February 29, 2012 11:53
AM
Subject: Re: [PSUBS-MAILIST] Electric,
Radio, Hull
I think the answer to your first question is a complex
formula that can't be made simple with the exception of possibly using other
subs as a guide. Most subs top out at between 2-5 knots
underwater. You might check the archives because it's been discussed
before but I don't recall the particulars.
Re: Radio Frequencies; use
whatever is required in the jurisdiction you are operating. In the US,
marine band is required when operating off-shore or within intra-coastal
waterways and if operating inland PSUBS guidelines recommend FRS
frequencies. Some sub operators use CB frequencies inland.
Re:
elliptical vs sphere; do you mean a tank head? If so, they are usually
purchased. A tank head can certainly be made up of segments welded
together to form a specific shape (which saves weight) but the difficulty of
doing so is not something I can speak to.
Check www.psubs.org
-> Resources & Reference -> Design Tools for software that can be
used for various submarine components design.
Jon
On
2/27/2012 9:01 PM, Stratus Radix wrote:
Hello I have a few questions:
First: How to you calculate the Electric motor size needed to go a
certain speed. I know drag and water dynamics matter but I just want a rough
sketch. Also when powering the motor is it better to use AC or DC?
Second: What radio frequencies do you need at sea and what types of
radios would you need also.
Last: Is it difficult to build an elliptical bow rather than
a spherical bow? Is it worth it? Is there any software out there to help out
on Submarine design?
This isn't really an important question but, what are the
positions/stations of a submarine?
That's all, thanks!