Re: Hobbico Superstar 40 electric conversion recommendations?

Doug McLaren wrote:
In article <1150408249.22960.0@xxxxxxxxxxxxxxxxxxxxxx>,
The Natural Philosopher <a@xxx> wrote:

| > What about battery cool down time? | What battery cool down time?
| | None needed with LIPOS.

Well, if you push them really hard, you might want to let them cool a
bit before charging again.

But LiPos aren't quite like NiCds there. If you push them hard enough
to make them hot, then they're not going to last long anyways. And if
your pack says 20C, and you actually fly at 20C, they won't last for
many cycles at all.

Exactly.


| > How much time do you think I spend wiping down a plane | > between flights? 30 seconds for the wipe-down, and a minute or two to fill | > the tank (why would you want to drain it?) is plenty. You can land and | > charge and be back up in three minutes? Wow!
| | Yes.
| If I have two packs charged last night ;)

Well, that depends on how accessible the battery is. Some can be
changed trivially, some require disassembling the plane somewhat.

(And if you're using LiPos, wouldn't packs you charged last week be
fine?)

They would be, but I always pre charge just in case.

Anyone who builds a LIPO battery into a model is asking for trouble. Mine ALWAYS get charged in at least a little ceramic pot, in case they catch fire.

The FIRST thing I do on landing is remove the battery. No one walks around with a live electric model - twice.. or leaves batteries in a model that is 'switched off' twice...they flatten in a few days and are suitable only for target practice after that.


| > It seems obvious that you have an ax to grind against glow planes. I have | > nothing against electric planes. They are more expensive

Well, they're only more expensive once you get above a certain size,
or get into the high performance stuff. Unfortunately, that certain
size is probably around the speed 400 / 1/2A size.

For your speed 400 park flier with a can motor and NiMH batteries,
electric is certainly cheaper.

I have found that the crossover pointy has moved up a bit. speed 600/0.25 size is almost the same pricewise as a glo installation overall.

40 sized stuff is still expensive, but no longer excessively so, especially when compared to a quality 4-stroke, which they emulate remarkably well. In fact many 40 4 strokes setups will fly very well on a speed 600 style power plant..larger props and gears make for as good a level of power for a slower model.




| Electric aint expensive any more

You must have a lot more money than I do! Personally, I'd call a
brushless motor, ESC and battery pack appropriate for a 0.40 sized
plane to be expensive.

Then don't use expesnsive brushless motors. LIPOS are de rigeur for me, but its amazing what you can find out there at sensible prices if you don't abuse them and run at lower discharge levels.



(And while brushless motors aren't _intrinsically_ signifigantly
better than brushed motors, in practice once you start getting into
the decent brushed motors, you can have a decent brushless motor with
a little better performance for a little more money. At this point in
the game, brushless is pretty much the way to go unless a cheap speed
400 can motor or smaller is adequate.)

| and because you can fly almost anywhere any time

Depends on the plane. I wouldn't suggest flying a 0.40 sized plane in
your front yard, electric or not.


Oh, Out back over the fields a 40 sized plane is OK..I have about 2 ten acre fields to fly OVER, and short tracks to land on..I've flown a slow 60" no worries there...Probably will use teh club strip for my next project - 78" span, for about 350W of second hand ASTRO cobalt power.

On the other hand, I've flown my glow powered (0.061) Superfly in my
front yard (well, I took off and landed there, but flew over the
street and other houses), and I live in your normal neighborhood.
Nobody noticed. It's loud, but not really any louder than a weed
wacker.

Round here I won't even fly a Picojet very often - makes about the same noise as an unmuffled 049..We are VERY quiet up here...;-) Yes these things aren't louder than weed whackers or a chainsaw especially..BUT I don;t use a chainsaw at 100ft in the air over the neighbours house ;)

And I try not to use the power tools much on Sundays as well.



| and LIPOS stay charged fore months and don't need topping off,

Of course, for long life you want to leave them about 40% charged.

Allegedly. In practice I haven't found a great deal of difference.

| I personally don;t have to travel 20 mile to a club and cram in as many | flights as possible in the 5-6 hours I am there. I can just have three | of four ten minute flights on a single pack, and then walk 50 yards, and | charge the thing back up. In my home.

I don't think he was ever denying that electrics are convenient.

| > They have obvious advantages. They work well in the winter, are quite, less | > mess, and less ground support equipment. Price and flight time are not | > advantages, though.
| | I fly longer than most glo flyers seem to. I can get 3 10 minute flights | in a single charge.

Depends on your plane. And really, if a glow pilot wanted a plane that
could fly for an hour, he could easily make one.

Ditto electric. In fact I have one that will.


| > A good engine, and not a knockoff, will be easy to teach a beginner how to | > adjust

Of course, I've been flying glow for years, and that's what I hate the
most about it -- getting the engines running right.

| > and once adjusted, (for the first flight of the day, 1 to 3 clicks
| > on the main needle is average) will not need anything other than
| > attaching the glow battery and a bump by the starter. I could
| > have started my plane in less time than it took to read this
| > paragraph.
| | I could have started mine in less time than it takes to type a single | character...

Odd. It takes longer than that for me to plug it in. But yes, nobody
is saying that electrics are hard to start.

| Flap away, but the sales figures for electric machines tells the rest of | the world that you are basically wrong.

Wrong about what? I don't recall him saying that glow was better or
more popular, only that he'd suggest a glow engine for that 0.40 sized
trainer.


I hiunk he was suggesting that glo would be more aopproriate for beginners ...I asked in my model shop and 'we haven't sold a glo engine in 6 months apart from an RCV for a scale project'

OTOH teh electric stuff is flying out of the door..

Personally, I think an electric setup for a 0.40 sized trainer would
be better as long as you can spend enough to 1) get 15 minute flights
and 2) have at least three battery packs and 3) have performance
comparable to that stock 0.40/0.46 engine, however I also know that
this will cost quite a bit of money -- probably well over $500 just
for the power setup (with most of that going to batteries.) Compare
that to the glow alternative -- $100 for the engine, $10 for a servo,
$5 for a gas tank, $10 for a gallon of gas.

I think $300 is nearer the mark..you DON'T need more than two packs really..I have less packs than models in which to put them ;-)

With about 3 x 8 minute flights from a pack, you can get in 6 flights out of two packs, and realistically have the model back in the air after 20 minutes having put the first pack on charge...the club flyers seldom fly greater frequencies than that on glo.



| People like electrics, and they now have the performance required to
| do a more than adequate job.

Did anybody say otherwise?
| A decent flight pack for a 25 sized model costs less than the ARTF
| it goes in these days.

You're on crack there. Or perhaps you have a different idea of
`decent' than I do.

A 200 watt power pack - 3s LIPO 2200 mAh - comes in around $40. That will fly a .25 sized model more than adequately.


Your typical ARF costs under $200 -- often around $100. Please, list
some decent flight packs (I'm assuming that we're talking about
motor+esc+battery rather than RX+servos here) that will cost less than
$200 for a 0.25 sized model and give similar performance to that 0.25.
Also, try and restrict yourself to something that will give us at
least 15 minutes of flight time.


Well as I say the pack is around $40. The cheapest way to use that would be a geared car racing motors - something like an magnetic mayhem or endoplasma, at around maybe $30, with a gearbox...say $20 - and a controller around the $30 mark.

I make that $110 all up.


| Motors have never been cheaper either.

Sure, but the motor is probably the cheapest part of the drive train
if you're talking about decent stuff. A brushless ESC generally costs
more than the motor, and the battery even more.

So don't use brushless.
LIPOS are so light, that half the time you need a heavier motor up front to balance anyway. The difference between a 65% efficient ferrite brushed motor and an 80% efficient brushless is marked in terms of heating on the smaller motors, but almost irrelevant in terms of overall flight times..so you put a bigger motor in, and suffer a 15% reduction in flight duration. Big deal.


Electrics are here, and their market share is likely to only increase
as the technology improves and the prices come down. But for now,
electrics do still tend to be expensive once you get above the 0.10
sized plane or so. I'm looking forward to the prices coming down,
however.


No. Above .25, yes. A decent 40 sized setup still is in hundreds of dollars, but below that its cheap as anything.

Once you have a few packs as well, because motors and ESCS (brushed) are cheap, its cheaper to have more planes as well.

A typical '049' replacement pans out at about $30 for the battery - shared over several models, about $20 for the ESC, and about $20 for a speed 400 and gearbox.. Thats $40 for the power train that is intrinsically 'bolted into' he model..OK to get a little more power you need a $50 pack and a $22 motor and gearbox..

....and the cost of 4 servos and a receiver is going to be around $100...I spend more on servos than I do on motors and geraboxes and the like.

Packs are the biggest SINGLE item on the ticket. But when I look at my expenditure its a sad fact that the largest costs go into glue, sandpaper, balsa, covering film and the like..and control horns and pushrods etc etc.


.

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