[chbot] Chchrobotics Digest, Vol 69, Issue 15

[Volker Kuhlmann]

On Tue 25 Jun 2013 23:36:32 NZST +1200, Marshland Engineering wrote:

> 1 m3 of air is 1.2 kg or 1 m3 of air is heavier than a 1 litre of
> milk!! Looking at it this way, planes now make more sense. AIR IS
> HEAVY

I believe you are mixing up specific weight with viscosity a bit.

> Ok so how much energy does it take to move it in a vacuum cleaner. A
> lot. Most cleaners are 1000+ watts. So how long will a 12 volt
> rechargeable last at say 500 watts ??? Not long.

Uhhmm, right result, but wrong reasons I believe. Moving something with
high viscosity that weighs 1.2kg/m� does not take that much energy.
Working against all the turbulences in the pipes, pump and corners of the
noisebox is the dominant effect. Plus working against the air inlet
being restricted to a fraction of its size - to increase air speed and
be able to pick up the stuck dirt etc.

So yes, those little toys are just that. One of my family uses it to
keep the varnished floor clean from all the pelt of the 3 dogs. It's
very good for that, but I don't think she expects it to keep the house
clean.

Volker

-- 
Volker Kuhlmann
http://volker.dnsalias.net/	Please do not CC list postings to me.