Cost of electrics

[Grow Pattern]

Keith,
          Which forum on RCU did you use to make the post?

I would add that controllers used at their limits do go up in smoke.

Also I have stripped gears and even snapped a shaft when the prop has 
touched the grass. (These electric props are up to 7" bigger in diameter 
than the glow props).

This was a big surprise and left me with no way to fix it at the field. The 
motor had to be returned to the manufacturer. Also swapping the motor at the 
field was not an option due to the need to use a high rated soldering iron 
to disconnect/connect the motor.

It seems that the field-support-solution is to have a motor already 
pre-wired to the  controller, or the use of some really good low resistance 
connector(s).

It's still a big learning curve that's for sure!

One final observation from the judges chair at the Nat's. I saw the YS 
1.60's operate against the electric of Jason's plane. They all did well! 
Jason won because of he flew the conditions better than the others.

Regards,

Eric.

----- Original Message ----- 
From: "Keith Black" <tkeithb at comcast.net>
To: <discussion at nsrca.org>
Sent: Tuesday, November 23, 2004 1:34 AM
Subject: Re: Electric power WAS : Diamond stab cross section - Dean Pappas


>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
>>
>
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