Wednesday, December 1, 2010

Re: [Electric Boats] Re: more regen conversation

 

Regen has always been a controversial subject here on this forum and will continue depending on which position you take..  I personally can't give you exact percentages on what would be acceptable for all of us, it depends on what we need in our own application.   We work with trade offs in each case and as we all experiment within our own budgets and expertise we will find the groove we can accept..  and the tradeoff's we can live with, so, we keep plodding along and sharing what we learn, that's what is the most exciting about this group..  Dave K


From: Eric <ewdysar@yahoo.com>
To: electricboats@yahoogroups.com
Sent: Wed, December 1, 2010 3:03:43 PM
Subject: [Electric Boats] Re: more regen conversation

Myles, your numbers look good.  I have noticed that most prop manufacturers use a 50-55% "slip" factor in determining the proper pitch for displacement auxilliary sailboats, so your 65-70% prop efficiency may be a bit optimistic for many of our conversions.

One problem in tuning a prop to maximize regen will decrease it's drive efficiency.  Since I'm personally more interested in drive efficiency to maximize my powered range, then I'm will to accept less regen.  You have clearly demonstrated why regen is limited due to the different water and prop speeds, so adding 20% to regen efficiency could make a small difference, but if came at the cost of 20% drive efficiency, it looks like a losing proposition to me.  Others may think differently...

Fair winds,
Eric
Marina del Rey, CA



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