[NSRCA-discussion] E Stuff

Sat Jan 21 10:20:34 AKST 2006

I, too, am relatively new to the E-learning curve.  I've learned a lot in the last few months, though.  There is a huge difference between a 2 or 3 cell foamy or micro-heli set-up and the 10s4p set-ups most are flying the "big stuff" with.  The most important thing I've learned is that you can't just "eyeball" these set-ups....the dynamics of airplane weight, wing area, voltage, prop size and motor are much more complex and demanding than a typical 2 or 4 cycle set-up.  

I fried an ESC trying to "home brew" a set up based on general specifications from a web-site.  It turns out I was pulling about 180 amps when the ESC turned into a torch!<G>  The good news is that there are plenty of reliable sources of information out there- it just takes some time to figure out where and who they are.  

I've been playing around with foamies and micro heli electrics for the past year or so, then I saw Nat Penton fly his Voodoo as an electric, and after talking to him about it, I decided to try a "big sized" pattern project.I had a Focus II kit sitting on the shelf, so I built it and "bashed" it into an electric --powered with a standard package-- Plettenberg 30-10, future 33.55 ESC and 22X10 APC-E; 2X  5s4p TP5300 packs in series.  One flight with that baby, and I was SOLD!  No noise but the wind on the wings and prop, unlimited vertical power and no vibration at all.  I don't have to mess with headers, engine tuning, fuel, oil, carburetors, valves, etc.  

I'm so convinced that e-power is the wave of the future, that I'm converting everything I have to electric- so that I won't have to carry two complete sets of support equipment to the field for a day of flying. I've converted my Raptor 50 to the Xero-G electric, I'm replacing my Vigor/Vibe with an Ion electric, and I've converted my Showtime and Funtana to electric.  My old YS 140 powered FocusII is also being transformed into an electric backup for the E-FocusII .

Icare-rc.com and hobby-lobby.com are both excellent resources in my experience...as a french canadian company, Icare seems a little more expensive and I have a little bit of a language barrier when talking to Etienne there.  Hobby Lobby is based near Nashville, TN and has been around forever (at least since I was a kid growing up in Memphis).  I have been pleased with their recommendations so far.  

Something that I've tried to do is limit the number of cell types that I need for different models.  I have 3s1p packs for small stuff like foamies and micro-helis-- then I have 5s4p packs which can be used as singles for mid sized (traditional 40 to 60 ) planes and as series pairs for 2 meter and large helicopter applications.  

I hope that the TP1010 chargers are great -  I use them with the TP balancers.....though I am not sure what all is going on as they charge.  The balancers come with sketchy instructions at best and when used with the chargers there are occasional errors on the 1010 when used with the balancer --like "wrong number of cells" even though the cell count entered is correct and the balancer alone says the cells are balanced; and (especially toward the end of the charge cycles) the balancers start beeping and chiming and flashing lights.  I hope that they are doing what they are supposed to do, but the documentation is scant.  I have not used them to charge packs in series!  I have enough noise charging them as singles!<G>

The old Astro 109's are simple and seem adequate for the job, but don't make a lot of noise<G>.

A wattmeter of some type also seems to be essential ...whether it is a watt's up type inline meter or a clamp on wattmeter.  As I found out by taosting an ESC- you have to test the current drain of each set-up-- you can't just "see how it flies" like you can with a combustion engine.  

Sorry If I've gotten too long winded...I've been a little frustrated by the lack of condensed, easily accessible information so I think that this thread may be the beginning of a much needed resource!

George

  ----- Original Message ----- 
  From: Steven Maxwell 
  To: NSRCA Mailing List 
  Sent: Saturday, January 21, 2006 11:45 AM
  Subject: Re: [NSRCA-discussion] E Stuff

   Good post Earl. I hope other's will contribute. Just to add a little to the mix there hasn't been much in the K-factor either on the electrics.
   I have started a make over to a plane that was setup for glow and done a lot of cutting to change to electric, one because it wasn't finished so it never had fuel in it, so it was still a clean place for epoxing.
   One of the big differences that I'm trying is use of less battery packs than others only 2 sets as opposed to most pattern guys seem to like 4 sets, as time isn't an issue with me. I'm fortunate to be retired so I can spend 6 to 8 hours at the field in good flying weather so if I get 4 to 6 flight in that time I'm happy.
   There are some cost cutting's that can be done but until I finish and get flying I'll reserve any conclusions.
   The one thing I will say right now is do your research, and don't make any hasty choices there are lots of options. Best to go with a proven setup.
   Steve Maxwell

    ----- Original Message ----- 
    From: Earl Haury 
    To: Discussion List, NSRCA
    Sent: 1/21/2006 12:06:00 PM 
    Subject: [NSRCA-discussion] E Stuff

    The E info on the list has been scant. Probably some are reluctant to hype / criticize products because of their involvement with suppliers. Some of us are just blindly exploring options, gathering data / information, and forming opinions without experience to back up our conclusions. Certainly information offered by those with experience is very welcome and appreciated. Those who are qualified experts in the various fields that can correct / clarify information gained through the school of hard knocks are not only welcome, but I suspect somewhat obligated to protect the rest of us. As this entire topic expands there will be conflicting opinions which in themselves provide info - that's what this list is for and no one should take offense that some prefer other views.

    After teasing the E guys at the Nats I recognized that the E powered airplanes flew better (I'll admit to being obstinate - but not totally dumb). There were also differences that seemed related more to E equipment choices than differences in pilot skills. The info published by Jason, Frack, Adam, Chad, and others (in RCU forums) provided an insight to the various equipment choices (and passionate defense of same in some cases). Interestingly, a lot of the discussions revolve around equipment type rather than the effect on flight characteristics.

    So - I set about trying to determine if E flies better and why. So far the answer is yes and I'm not sure. While differences in dynamics can be identified, it's hard to quantify the effects. For example, the lighter / slower rotating E prop generates a lower gyroscopic precession force during looping maneuvers than glow - this also suggests the lower rotating mass of a geared motor might be better. The lighter motor (compared to glow engine) up front can result in a lower pitch moment of inertia if the tail is light enough to allow the battery mass to be close to the CG. Airplane smoothness in rough air is markedly better with E. (I did most of my comparisons with twin Partners - one glow and one E - at about the same flight weight.)  This may be an effect of the large diameter prop or lack of vibration effect on the servos. As others have noted, thrust application is very good with E as the slower prop is efficient and the mo! tor is instantly responsive and very linear. E can be flown slower than or as fast as glow, the airplane is more stable with E when slow  - again probably the large prop effect. Overall, it's easier to fly well with E but E won't fix sloppy flying.

    As with most things in model aviation - there are learning curves. Some suppliers are better than others, some equipment is better than others, some choices will be revisited after experience is gained. The hardest thing to get used to is the metrification of cost - kilo dollars. Not that E is that much more expensive than glow - just that very little from glow is useable with E. That means one must acquire motors, controllers, batteries, chargers, power supplies, meters, connectors, wire, props, etc. pretty much from scratch.

    If there's interest in this becoming a thread I'll discuss the reasons for some of my choices of equipment and the data I've generated / will generate with the full understanding that I might be operating under false assumptions and some of this stuff will change - I'm still learning.

    Earl

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