For those wanting to go electric, my long story

Yup. I lucked out and came across it early. There's still the terminology and basic technology to wrap inside your head, but MotoCalc will quickly get you up to speed.

On Mon, 13 Mar 2006 02:32:22 GMT, "desmobob" wrote:

Yes, your story was long and worth every word. I didn't snip a thing. You have done a service here whether that was your intention or not. I am a brushes flier and do not own a LiPo pack or brushless motor. I haven't worn out what I have but I have decided that it will it all outlast me so I will most likely get rid of almost all e-things and start over with current (no pun) technology. And I would have the same problems in understanding the present stuff as you do/did. My choices will be the same as yours; learn it the hard way or ask someone I trust and follow his recommendation...the other one is get an ARF close to what I want and then learn from trial and few errors with simple mods. That is what I will do because I want to know how the new stuff works. I am a retired NASA electronic engineer so I should be able to learn the details of the limited range of performances in which I would be interested. Now the second thing is the MotoCalc you mentioned. I have E-Calc and because of the many variations in batteries, props, gears, motors, etc., there is just no way a guy can live long enough and have enough money to do all the experimentation in the shop and field. I believe that E-Calc has easily saved me $400 dollars and almost as many days of testing. (I have used mine for 10 years.) I have sat here and gone through the program, printed it out, and then gone to a contest. If the wind comes up (or goes away), I might switch props and batteries as recommended by E-Calc...or I might even change motors, gears, and prop. I have done this without any prior testing! I would do what I had figured out would optimize my variables, rig the model, check the CG, and get me a timer, my score card, and head out to the flight line for a launch. Sometimes there would be a minor improvement; sometimes, it would result in an award I would not have otherwise had gotten. So ... fellows, ya' wanna' save money? Ya' wanna' save time? Ya' wanna' "fly" dangerous combinations while sitting at the computer? Get one of the computer programs and have fun.

Ken

I think this is a good example of what keeps a lot of modelers out of the wonderful world of electric. It is like starting all over in the hobby again when they are comfortable with selecting the right engine, prop for fuel powered models. Some, regardless of age, are still excited about learning something new. Others will no doubt chose to remain club experts until there are no more that really care or need their expertise.

Red S.

convenience

Too bad they don't do them for Macs...

| It is like starting all over in the hobby again when they are | comfortable with selecting the right engine, prop for fuel powered | models.

They're not starting over completely. Most of what they know still applies -- what needs to be (re)learned is relatively small.

Knowing how to make guesses at the appropriate power plant for a given electric plane is far simpler than knowing how to recover a plane, or repair a plane after a crash, or build a plane, or even how to fly a plane -- things that haven't changed that much. And as batteries and motors improve, the situation will only improve.

(Glow engines generate oodles of power for their weight, and so you can put a specific engine into a large number of planes and it'll work fine. As electric power plants improve, you'll find this being the case with electrics more and more often as well.)

Granted, with electrics has come the age of the foamie, and building/repairing foamies is very different than balsa planes, but foamies are not a recent innovation -- they've been around for quite some time, either as gliders or powered by rubber bands or glow engines, and now electric motors. And even though building may be largely different, it's still largely the same, and flying foamies is very similar to flying built up planes.

| Others will no doubt chose to remain club experts until there are no | more that really care or need their expertise.

This sounds like it's supposed to be an insult, but I don't see where an insult is appropriate here.

If somebody is an expert at glow/gas flying or building, and they like this and don't feel the need to try electric, what's wrong with that?

Is expertise wasted just because nobody wants you to share it with them?

And in any event, I know several people who have never touched an electric plane who know far far more than I'll ever know about building or flying, and I still find them to be useful resources. I may not ask them about adjusting the timing on my motor, but `what's the best way to repair this wing I just broke?' -- you bet!

Maybe you can shed some light then on why some resist even trying electric so much and seem to detest even the thought. Do you suppose they were the same way when we transitioned from free flight into radio control, ignition engines into glo, silk/tissue and dope to today's covering materials? There are still a very few that will risk losing an expensive antique ignition engine in a free flight rather than add a few grams of radio control to at least keep it in the confines of a reasonable search area. ????????????

Until the battery technology improved and a few RTF electric models came along, I was pretty much anti-electric.

Why? Because I used to watch a few friends of mine in the early eighties try to fly electric back then. There was just no performance to be had and the flight times were extremely short, not to mention the horrendous expense of electric technology. When my friend moved away to Florida, that ended my exposure to electric flying, so for twenty years I kept thinking that electrics were the way they had been in 1980, which was wrong, of course.

Also, I was younger and much more fit back then. Handling larger models with big engines was no problem in the days long passed. Today, the compact electric models that I now own that are inexpensive and which provide fairly long flight duration are a blessing. No clean-up. No massive assembly at the field. No aching shoulders and hands after a day's flying. I'm a convert, although I still mess with the glow and gasoline powered models when I'm having a really good day.

I have a few RTF models that utilize lipoly batteries. I haven't flown them as yet because you have to discharge the battery completely and then charge it for two hours. My problem is that I forget things and I'm afraid of burning the house down.

Is there a charger out there that will detect the type of battery that is plugged in and then terminate the charge at the proper time? Preferably one that does the decision making automatically and autonomously? TIA

Ed Cregger

On Mon, 13 Mar 2006 16:11:37 -0500, "Ed Cregger" wrote:

Ed, you reminded me of something that happened on our IC field one day. This was way back and I was one of the first e-fliers around and when I arrived out there, I showed them my AMA card and asked if I could put in a couple of flights to test a battery pack. One of the guys asked, "Are you sure you want to give it a try. It is pretty windy." I told him there would be no problem and he said, "OK, but take a look at that fence over there. It is up wind. Will you clear it OK?" I really thought he was joking and I laughed and said that I thought I could clear it. Then he said, "Well, we had a couple of guys flying some of those electrics out here last month and one of them sure couldn't." I have no idea who those e-fliers were or what they had. I turned lose my 5-turn cobalt and it went up at about 60 degrees. The guys on the field couldn't believe and then said the usual, "they are too heavy and don't fly long enough." I asked, "Long enough for what?" No one ever really gave me an answer to that. Half an hour later, I was still up and they were asking me what sort of battery I had in it. Some of the early things really didn't have much power but this was well after that, yet, that is all those IC fliers had seen. By the way, the club virtually came apart because I later said we were going to lose our flying field if the club didn't have a muffler requirement. They refused to have a muffler rule because...they all "knew" that they made the engines hard to start; made them run too hot; took away too much power; wouldn't let the engines idle right; and after being on idle, they were apt to die when full power was needed again. I have a hard time remembering how primitive those guys were

-- I guess somewhere there are fliers still saying the same thing about electric power though they have learned to use mufflers.

Ken

Ed.

If someone told you (the instructions maybe) that you have to discharge lithium completely before charging they were misinformed. If you are using a lithium charger it will charge to the level set by setting the number of cells and that's it. It usually takes, if you have set it to charge at or near C rate (which is recommended), a bit over an hour to 90% charge from fully discharged battery. So far there is no charger system that will differentiate the type of battery being charged, but if you are using a lithium specific charger then that becomes a non issue, more of plug and play because it will detect the number of cells. Some chargers will alert you if you set the wrong number of cells. All you do is enter the battery capacity which sets the charge rate. There are probably some that will adjust the charge automatically so you don't even have to do that.

Always charge you packs out of the plane and on a fire proof surface with nothing around to ignite. A 12" square slab of tile and cover with a clay flower pot is all you need to be completely safe.

----- Original Message ----- From: Ed Cregger Newsgroups: rec.models.rc.air Sent: Monday, March 13, 2006 4:11 PM Subject: Re: For those wanting to go electric, my long story

I have a few RTF models that utilize lipoly batteries. I haven't flown them as yet because you have to discharge the battery completely and then charge it for two hours. My problem is that I forget things and I'm afraid of burning the house down.

Is there a charger out there that will detect the type of battery that is plugged in and then terminate the charge at the proper time? Preferably one that does the decision making automatically and autonomously? TIA

Ed Cregger

| I have a few RTF models that utilize lipoly batteries. I haven't flown them | as yet because you have to discharge the battery completely and then charge | it for two hours.

Are you sure that's how you charge them?

LiPos are easy to make a relatively slow charger for -- just take a wal-wart, add a 4.2 volt/cell voltage regulator, add a resistor to limit the current to a reasonable value and let charge. Even leaving them on the charger forever will not overcharge them.

The `discharge fully and then charge for X minutes' paradigm was common for NiCd and NiMH cells, but I don't see where it would be appropriate for LiPos. Especially the `discharge fully' part -- discharging LiPos fully ruins them.

| My problem is that I forget things and I'm afraid of burning the | house down.

Well, if it's RTF, they're almost certain to make it pretty much idiot proof. You don't worry about your cell phone charger burning your house down, do you? It's probably LiPo or Li-ion too ...

Well said. I enjoyed reading it and I'm sure it will help some of those getting started in Electric.

Ken Day

Ed. I have owned a number of chargers including the Triton. I have an Astro Flight 109D which , IMO is one of the best LiPoly charger /dischargers out there. I've had it almost 2 years now and no problems or complaints whatsoever. It's completely automatic except for the charge rate.Thats all you need to contend with. On discharge it has only one rate at 1.25 ma. The LED readout tells you how many cells, capacity , and voltage. When charging you know exactly how much capacity was left in the pack . and of course how much you put in. It only charges LiPoly cells and will charge up to a 10 amp rate. I have charged 3s5p 1500 ma cells with no problems. I charged them as

Ken Day

I suspect that your last paragraph is dead-nuts on target. I always get confused when I encounter idiot-proof items. Especially Chinese written in English idiot-proof instructions.

Ed Cregger

Sorry about the pathetic post. This is what happens with sleep deprivation. All better now.

Thanks for the tip on making a grenade proof enclosure, so to speak.

Ed Cregger

Thanks for the info, Ken.

I have a couple of chargers that I have been thinking of using. One is Hitec and the other is Multiplex (Hitec again?). These I would use on my larger models, not RTFs.

I just don't understand why they would make this as complicated as it is for an RTF. Maybe I'm reading too much into their idiot-proof instructions...

I have both a Clancy Lazy-E-Bee and a Honey Bee II heli, in addition to a Clancy Ascender to enjoy. Gotta get some calm air to fly them in.

Ed Cregger

Its easy enough these days..there are a range of outrunners and LIPO packs that have a very similar RPM/power characteristic to IC engines, and models are now available that are designed to suit them.

Plug and play time for those who aren't interested, and have the deeper cheque books, is here.

You never *ever* discharge a LIPO completely Ed.

You can recharge them from any state of cahrge, and if you have only used 1/3rd of tehe capacity, its about 20 minutes

Get an Astro 109. For LIPOS.

LCD on an astro 109, not LED.

tells you how many cells, capacity , and voltage. When