Total Newbie Question...

[irish_lord99]

Alright, so I really should know this by now, but the truth of the matter is that I've never built a plane without a motor/ESC setup for RC before, and I'm hoping to do a small glider from plans that I took out of a "Flying Models" magazine. I've got a project on the board now, but I'd like to get started with the "Pocket Peregrine" soon after that's done so I'm rounding up electronics now.

My question is this: do I actually need a BEC or some-such device between the battery and the Rx, or can I attach the battery directly provided the voltage isn't too high? I do have a spare BEC lying around but it's about 13 grams and I'd rather save on the weight if I can. I'm using standard 72Mhz gear, and I'd probably use a two cell Lipo, but I'm sure I can buy a Nicad pack around here if that's better.

Any info or advice on the matter would be very useful.

Thanks,

~Jake

[prodjx]

If it's just for a glider no BEC is needed.

[scaflock]

If you're going to power your RX off a LiPo then you'll need the BEC for sure. If you don't use one you'll fry the RX. LiPo batteries have way to much amperage and voltage for a RX. If it's just a glider then you'll need a RX battery to power everything.

[irish_lord99]

That's good news! what would make a good RX battery then? I'm guessing a small Nicad?

Thanks for the quick reply,
~Jake

[Resurgam]

Rx battery is usually four or five cells, NiCd or Nimh. Sanyo Eneloops are getting good results these days. very low self discharge. The Eneloop AAAs are rated at 800mah which is fine for a small glider.

[HerkS]

Have flown several pure gliders using a ESC and LIPOs. Just insulate the motor wires and don't hook anything to them. As long as the BEC on the ESC can handle the number of servos -- and as long as the ESC is suitable for your LIPOs it will work fine.

[irish_lord99]

Resurgam, thanks, I'll probably be able to find a guy around here that sells packs like that.

This is a rather small glider with only a meter wingspan and two channel control. I'm hoping to keep the weight under 120 grams, and the battery will be the heaviest component, I'm sure. I have several 350mah lipos, but the guy who drew up the plans said that he only used 100mah... he didn't specify whether it was lipo, nicad, or Nimh. Either way, I'd just like to go as light as possible and I don't think I need a very big battery to power two micro servos for the duration of the glide. :)

Thanks again,
Jake

[Phil Barnes]

You need to step into the hand launch forum. I don't have time to do the search for you right now, but there are threads about using lipos for DLG models (all are 1.5m or smaller wingspan). There are also lipo regulators available that weigh under 3g and full discussion threads about them. A quick post in that forum would bring guys out of the woodwork instantly with links and all information that you need.

[Brian Molloy]

Regulators and 380mah Lipo packs:

www.rcbuilder.com

[wsnowfall]

if i understand correctly, you are just setting up a glider, no motor.

Some guys use 2s liops and a voltage regulator. i got some from common sense. i also use enveloops. that is viable. one factor how much nose weight do you need for balancing? envelooops may be the way to go.

bill snow

[irish_lord99]

Another guy on the forum sent me a link about using normal camera batteries... I may try that, they're not rechargeable, but he claims that for a small two-servo bird they will last him about six months.

http://www.rcgroups.com/forums/showthread.php?t=966437

Part of my problem is that I live in Turkey and it's difficult to get stuff sent here, anything that I can make out of local goods is best.

thanks
~jake