Electric power as regards cost

[George Kennie]

Keith & Del,
The reason for my post was to elicit the exact responces that I have been
receiving. I too have some cost concerns and realize that I am not capable of
thinking of everything! I love the fact that I can always count on guys on this
list countering everything I state in my posts with additional enlightening
info.
At this juncture in time I think I am going to dabble a little in something a
little smaller as I don't think the big stuff has reached a point where it can
compete on a cost basis with liquid fuel in light of the fact that there are
some still unanswered issues.
Georgie

Keith Black wrote:

> A few weeks ago I put together a list of questions directed to those already
> flying electric pattern in hopes that their responses would help those
> considering electric pattern. Unfortunately there were no responses to the
> questionnaire on this mailing list and only two responses on RCU (thanks to
> Steve K. and Tony F. for responding).
>
> Based on the information I've been able to gather via these responses and
> other extensive sleuthing I'm not convinced that the technology is at a
> point that it will meet "my" objectives. This is not the result I wanted
> from the research, but it's what I concluded.
>
> My key concerns are 1) flight time, 2) reliability, and 3) life-span of
> batteries.
>
> 1. Flight Time: From what I can tell the max reasonable flight time today
> seems to be around 10 minutes. There are batteries with more capacity,
> however this comes with a weight penalty. Also, I don't think the limited
> time is purely a battery capacity factor, I think there are also concerns
> about how log the batteries can supply the high amp load before being
> damaged or getting too hot. If someone has some hard facts on this please
> speak up.
>
> For me 10 minutes per flight would be a big step backwards since I normally
> fly 15 to 18 minutes per flight. Being a new Advanced pilot I have a LOT to
> learn and just can't accomplish this without putting in a lot of stick time.
> Also, since my practice time is limited I need to knock out three of four
> 15-18 min flights in a pretty short time. I can't just sit around the field
> all day.
>
> 2. Reliability: I am 100% confident that a brushless motor operated as
> designed will last longer than most pattern planes. Brushless motors are
> extremely efficient and the ideal power plant. However, there are other
> things to consider. 1) Will the motors hold up under the 60+ amp loads over
> time, heat may be a problem. 2) How are the gear boxes holding up (where
> applicable)? and 3) How will the ESC (Electronic Speed Controls) hold up? I
> know from observation and experience in other electric applications that
> ESC's get burned out, sometimes much more often than the electric guys want
> to admit. Through all the research I did related to electric pattern I
> wasn't unable to find anyone that has hundreds of flights on a single speed
> control and motor combo. It may be possible, but no one out there is
> admitting to such luck.
>
> 3. Life-span of batteries: This of course is the thing that everyone zeros
> in on as the cost of operation. Assuming the motor and ESC don't need
> frequent repair or replacement then we need to make sure we get enough
> flights per battery pack to justify the $700 per flight pack. On a personal
> note I'm not looking at electric as a cheaper alternative to glow. I would
> go with electric even if it's incrementally more expensive because there are
> many other benefits that to me justify a premium. However, the most flights
> I've heard on a single pack is around 100 flights. I've also heard of many
> failures long before 100 flights. In fairness much of this may be due to
> early adopters of new technology. In most of these cases I think the mfgs
> are replacing the batteries. With the new higher C rated batteries the most
> I've heard of is around 50 flights. I'm not saying they die after 50, but
> I've not found anyone that has exceeded that yet, possibly because they are
> relatively new.
>
> I'm not suggesting that my findings are all accurate. I'm just sharing what
> I've been able to ascertain based on what others have been willing to share.
> I'd love to learn that indeed the current state of electric is much further
> along because I'm anxious to go electric when the technology is mature
> enough to meet my needs. If I felt that were the case I would strongly
> consider going with electric on my winter project.
>
> Keith Black
>
> ----- Original Message -----
> From: <JonLowe at aol.com>
> To: <discussion at nsrca.org>
> Sent: Monday, November 22, 2004 2:33 PM
> Subject: Electric power WAS : Diamond stab cross section - Dean Pappas
>
> > I hope Jason Shulman pops in here on the cost of electrics, but I
> understand that the big electrics are getting nowhere close to 1000 cycles
> out of their batteries.  What I hear is less than 100 cycles, in most cases
> CONSIDERABLY less.  Why, I don't know.  At $600 a pack, the cycles you get
> will change the cost effectiveness a lot!
> >
> > Jon Lowe
> >
>
> =================================================
> To access the email archives for this list, go to
> http://lists.f3a.us/pipermail/nsrca-discussion/
> To be removed from this list, go to http://www.nsrca.org/discussionA.htm
> and follow the instructions.




=================================================
To access the email archives for this list, go to
http://lists.f3a.us/pipermail/nsrca-discussion/
To be removed from this list, go to http://www.nsrca.org/discussionA.htm
and follow the instructions.