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electric question, as i receive no help in electric forum

Old 01-23-2008, 11:52 PM
  #1  
fozjared
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Default electric question, as i receive no help in electric forum

will this battery

http://www.hobbycity.com/hobbycity/s...idProduct=5462

work with this combo, or will it overpower the esc?

http://www.hobbycity.com/hobbycity/s...idProduct=4711

thanks in advance!

btw, i posted this in beginners because when it comes to electrics i dont know jack.. i want to learn, but its like i have a mental block!
Old 01-24-2008, 12:16 AM
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Default RE: electric question, as i receive no help in electric forum

The battery should work fine with that motor and ESC combo.

When combining electric components, the ESC is the key component. Every ESC should have a give range of voltage that it will worth with regarding the battery used. It will also have a peak current rating (25 Amps, e.g.) that will determine whether or not it will work with a give motor and propeller combination.

If you combine battery that fits the general voltage input parameters of the ESC with a motor that won't pull more current than the ESC is rated for, the power system will basically work. You may need to test various propeller choices with the engine (measuring with a wattmeter) and/or try various voltages or battery capacities to get your ideal flying results for your airframe.

Much like glow engines, there really aren't very many hard-and-fast rules about "best setups." A variety of components will work well on any given airframe, and you will need to try different combinations to see which you like best.

Good luck and good shopping!
Old 01-24-2008, 12:21 AM
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Default RE: electric question, as i receive no help in electric forum

It's fine...BUT...

That lipo pack is heavy, the ESC and motor are of fairly low quality and can be had for much less.

As a beginner, they will likely serve your purpose, but be prepared to replace them either after a single bad crash or a few months of flying. In truth, that combo will be fine for a while, but you will soon find that you almost always get what you pay for in this hobby.

Electric set-ups are difficult because there is no real quantifiable standard. KV ratings, RPM, ESC amp ratings and other specs are often inacurate and not tranferable between manufacturers...and in some cases within a given manufacturer's product line.

Try to find someone who has been down this road to help you. Don't buy junk. It costs more in the long-run.
Old 01-24-2008, 12:44 AM
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Default RE: electric question, as i receive no help in electric forum

well i will not be using these products as a beginner, i am just ignorant about electrics, not a beginner. i only choose electric for this airframe as it is the only option (it is a home built foamy that i plan to finish learning 3d on as i am decent at 3d at about 25ft off of the ground, but i want to bring it in close with this foamy) i agree with you on the electrics not having a standard, an electric setup can vary so much, it seems like there are 1200 different choices that would do almost the exact same thing as the next! i hate not being knowledgeable about something i am or plan to use though so i will force myself to learn this electric stuff! engines, man now they are right up my alley, i know engines front and back and glad that i have spent the years with larger engines (cars, trucks, motorcycles, etc.) before i got into rc, because everything is exactly the same, except smaller and more easily accessible as you can hold them in your hand instead of laying over on top of them, or walking/crawling around them! i have always had a knack for engines, but motors/other electrics its greek to me! if you guys think that this combo should work i will give it a shot on this 4.1 ounce 28" ws foamy! thanks!
Old 01-24-2008, 12:48 AM
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fozjared
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Default RE: electric question, as i receive no help in electric forum

oh yeah, agexpert, where can these items be had cheaper?

btw, agexpert as in agriculture? what's your profession? i will be a first year teacher next fall, and will be teaching agriculture. so i was just wondering, have been wondering for several months, ever since i first saw your name anyway..
Old 01-24-2008, 01:06 AM
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Default RE: electric question, as i receive no help in electric forum

one more thing, will 17.5 oz/in micro servos be enough for 3d flight on a 4.1 ounce foam airframe? 14.3 ounces after motor/esc/battery/4servos.. will they have good control on this plane? 28" wingspan.. will that motor/batt./esc work good for 3d on this plane as well? thanks for the info..
Old 01-24-2008, 11:41 AM
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agexpert
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Default RE: electric question, as i receive no help in electric forum

Fozjared,

I have been a professional independent entomologist, agronomist and consultant for 13 years in CA. I work in coastal crops of all types, pretty much anything someone will pay me to consult on. It's the best job I could ask for. PM me and I will be happy to share some of my experiences in California farming.

I checked my, used to be cheapest, website and they can't beat that combo, but it truly is inferior for what you want to do. http://www.tedani.com They carry stuff I won't fly for the most part, but their stuff was good enough when I was starting out.

The plane you have described is too heavy for 3D training, especially with that motor. I fear you will be disappointed. The most important thing to consider when learning 3D in the beginning is having the ability to 'FALL UP'. You need enough P/W ratio to power STRAIGHT-UP out of a bad situation, and quickly.

The advantages of foam for this type of training are numerous. It's cheap, easily repairable, and with the right equipment it can have as much as a 3:1 P/W ratio. Completely unrealistic for a big 3D gasser, but it will teach you the correct inputs....and it's more fun than any glow plane I have ever flown...for 3D, that is.

I also like the fact that I can fly foam anywhere. I keep one in the back seat of my truck and fly at will; parking lots, fields, yards, schools...anywhere. Just hover in front of your face and grab it. Throw it in the truck and move on.

If you really don't have more money to throw at this right now, keep practicing high until you do. A good 3D setup will cost around $300 for everything except a lipo charger.

I have flown many foamies. By far the best, IMHO are the ones from http://www.chargerrc.com. Get a CR-1, a good Hacker motor, 4 servos, a good ESC, RX and a THUNDER POWER 1320 3 cell lipo.

(BTW, I just talked to my buddy who owns Chargerrc.com. The site is being switched to a new provider and will back up later today...so try later).

If you get it trimmed right it will lock into a hover so well you have to gently force it out. It won't be long before you are touching the tail at will, doing low rollers and KE passes into a hover a foot from your face. Don't get the landing gear...learn to catch it. Until then, just gently belly-in on some grass.

Good luck!!
Old 01-24-2008, 12:00 PM
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Default RE: electric question, as i receive no help in electric forum

ORIGINAL: agexpert


As a beginner, they will likely serve your purpose, but be prepared to replace them either after a single bad crash or a few months of flying. In truth, that combo will be fine for a while, but you will soon find that you almost always get what you pay for in this hobby.
Eh, not necessarily so.

He's buying directly from HK cutting out many of the middle men.

You can often get the SAME motors sold here which have been rebranded, from the Asian originators for much lower cost.

Case in point the very TowerPro motors he purchased.

They are sold under many names here including the BP Hobbies brands, etc.

I've used the higher capacity motors in several planes and the ESC's, for YEARS now in several electrics and have had MUCH better luck with them, better power regulation to the servos, ability to handle higher voltages, etc. on those "cheap" ESCs ( you DO have to adjust the timing which is one thing that people who seem to have problems miss ), than say those "high priced" E-Flite P.O.S. ESC and motor combos sold here at three or four times the cost.

I have that particular combination which he cited in a Foamy with a 1800mAh battery and it flies just great.
Granted that particular one is not the greatest motor to begin with as it's targetted for fairly small electrics, but as you move up in size those "cheap" motors do very well for the price. Oh the efficiency may not be quite as good as say an AXI equivalent, but for the price you can afford to scale up quite a bit to compensate for any deficiencies.... and these are cheaper and at the very least equal to say RimFires or Ammo's.

I paid all of $30.00 with shipping for a BP2915D equivalent with hotter windings, and I've flown it constantly for the past two years on a Super Sportster EP, coupled with a cheap 40A ESC of the same brand. The thing flies like it has a .40 engine in it.

I put up a seperate thread called something like "30 minutes run time from Super Sportster EP" where I documented all of this and others have tried these "cheap" motor electronic combos with exactly the same great results.


Now all of that said, returns and after sales support ARE BIG problems with the "cheap stuff" as there is none. Beginners may have problems as a result.



Old 01-24-2008, 12:31 PM
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Default RE: electric question, as i receive no help in electric forum

If you want to practice and/or learn close in 3D the best setup's and planes I have found have come from http://www.chargerrc.com/. I fly a CR1 and a AXILON P-3D which are both awesome, they also sell motor, esc, and servo combos that rock. They have been the most bang for the buck that I have had in a long time and I enjoy they way they fly which makes my 3D much better on my big planes.
Old 01-24-2008, 01:52 PM
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Default RE: electric question, as i receive no help in electric forum

ORIGINAL: fozjared
if you guys think that this combo should work i will give it a shot on this 4.1 ounce 28" ws foamy! thanks!
You are planning to put
- 130g battery pack
- 65g motor
- 24.5g ESC
at close to 200W power

into a 4.1 ounce 28" ws foamy?

Too much weight. Too much power. Too little wing (or is it some unconventional shape?). It will not work.
Old 01-24-2008, 02:07 PM
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fozjared
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Default RE: electric question, as i receive no help in electric forum

it is just a flat wing, no airfoil about 1/2" thick blue foam with a 28" ws and a 26" fuse.. i really hope to purchase these items today, but i need to hear a little more feedback, i tend to agree with opjose, as i have a couple of friends who use these cheap packages all the time, but they are both out of town right now or i could get some feedback from them.. i realize that you get what you pay for, but just the same sometimes you pay more and get the same thing you could get for less elsewhere and under a different name or in different packaging! anyway, i will wait it out for a few hours and try to do a little more research on this electric stuff!
Old 01-24-2008, 02:32 PM
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Default RE: electric question, as i receive no help in electric forum

I have to disagree with perttime.

You are adding 7oz of weight to a 4.1 oz plane for a total AUW around 12-15oz by the time you are done adding servos, etc.

With the suggested 8x3.5 or 8x4 prop that motor is NOT going to produce it's rated max of 180 watts, it will be closer to 120-160 watts.

I've put this combo on a meter...

The plane will have unlimited verticals and will be an awesome flyer, but it shouldn't overpower it to the point of damage, provided the motor mounting is good and the plane is of typical construction with SOME reinforcement such as CF rods, etc.





Old 01-24-2008, 03:07 PM
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Default RE: electric question, as i receive no help in electric forum

The Loong Max Packs are quite o.k.

I have been using a pair in a Phoenix Rainbow (sold in the USA as the Graupner Electro Kadett via Hobby Lobby) for quite some time and they are every bit as good as my Polyquest and Hyperion packs, which are sold at more than double the price. However, what the maximum life of the Loong Max packs are, in terms of recharge, or cycle capacity, I have yet to find out..

The pack you are looking at is good for up to 24 amps current discharge ("C rating x Ma/H capacity of the pack , in this case 1600 x 15 = 24000 or 24 amps) which is 4 amps more than the maximum capacity of the motor.

In the EP flight game, a device such as an E-Flight Power Meter , or the hard to get Hyperion E-Meter is a very handy tool to have.

Assemble your motor/prop/esc and battery combo, connect them up to the Power Meter or whatever you have, run it at full throttle for 10 or so seconds and record the readings displayed by the measuring meter.

Fit another size prop and repeat. Keep doing this until you find a prop that gives you a result that is as close as possible to the maximum efficiency reading that the motor manufacturer specifies. (In this case 15.5 amps, the max quoted on the Hobby City motor stats sheet) But at the same time, ensuring the capacity of the ESC and battery are not compromised. The motor manufacture will give you a prop size in the instructions, that is a good starting point.




Old 01-24-2008, 04:01 PM
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Default RE: electric question, as i receive no help in electric forum

thanks so much guys, i think i will stick with that combo, i spoke with one of the guys that i know and he also agreed that this setup should work fine.. thanks for all the input, i will let you all know how it flies when this stuff arrives!
Old 01-25-2008, 02:55 AM
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Default RE: electric question, as i receive no help in electric forum

ORIGINAL: opjose

I have to disagree with perttime.

You are adding 7oz of weight to a 4.1 oz plane for a total AUW around 12-15oz by the time you are done adding servos, etc.

With the suggested 8x3.5 or 8x4 prop that motor is NOT going to produce it's rated max of 180 watts, it will be closer to 120-160 watts.
I have no doubts about the power to weight being enough.

My doubts are about wing loading. I'd expect to see that kind of a power system and weight in a larger plane. Like a light built flat foamie of 35" to 40" span.
... Competitive indoor aerobatic foamies, at around that size, tend to have AUW around 5 or 6oz. (well below 200g anyway).

A 12-15oz GWS Formosa (more like a pattern plane) would fly well on this system, although I'd really hope to get a Formosa closer to 10 than 15oz.
Old 01-25-2008, 12:47 PM
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Default RE: electric question, as i receive no help in electric forum

Strange debate...
Why is it only perttime who have hit the nail so far?
For small 3D foamies the main factor is weight, or lack of weight! For the size I would say 180 gram AUW is a bit heavy. 400 gram is... well, it is not a good 3D-plane any more!

My choices for planes this size: AXI 2204/54 and 2S or 3S 450mAh LiPoes. Motor, ESC and battery weight appr 80 gram total on 3S. (Less than 3oz I think) Performance is less if you put in 15gram servoes instead of 6 gram servoes
Old 01-25-2008, 02:11 PM
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Default RE: electric question, as i receive no help in electric forum


ORIGINAL: perttime

My doubts are about wing loading. I'd expect to see that kind of a power system and weight in a larger plane. Like a light built flat foamie of 35" to 40" span.
He didn't stipulate which plane though.

My small Yardbird RC F-22 foamy with 24" wing span has NO problems with this setup at all and it's a bit smaller than his.

I'm running a 2200mAh 15C pack on it.

It's not a 3D plane though.



jooNorway:

You sort of missed the point. ( and the "nail" ).

He already has the combination, and wants to know if it will work on his plane.

The answer is YES it will work just fine.


Old 01-25-2008, 03:04 PM
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Default RE: electric question, as i receive no help in electric forum

ORIGINAL: opjose
He didn't stipulate which plane though.

My small Yardbird RC F-22 foamy with 24" wing span has NO problems with this setup at all and it's a bit smaller than his.

I'm running a 2200mAh 15C pack on it.

It's not a 3D plane though.
"He didn't stipulate which plane" and you are willing to bet his money that it will work very well for 3D?
Actually, we know something about the plane:
ORIGINAL: fozjared

it is just a flat wing, no airfoil about 1/2" thick blue foam with a 28" ws and a 26" fuse.
For all I know, it will end up as a .15 size plane with a .90 engine and a big fuel tank.

If the wing is a 28" x 26" rectangle, it might work. If it is a "conventional" plane. It will be too heavy for the wing area, as a 3D plane.

I am still worried about the wing loading, untill I know more about the plane.


Old 01-26-2008, 02:55 AM
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Default RE: electric question, as i receive no help in electric forum

His model is not going to fly like a conventional airplane. He stated that the wing has no airfoil section. So it's safe to reason that it will be a 3D profile type model, hovered just like a helicopter, so there will be no great aerodynamic stress on the airframe.

For this type of "flying" (for want of a better word) he will need power and lots of it.

However, the choice of a 3 cell lipo of that weight is, as pertime says, a concern.

For the battery, something in the 700-900 Ma/H size would be more suitable.

I have a 5.2 oz Edge 2Xtreme (pic is from the web as my camera is "bruk") and use a 3 cell 800 Ma/H Polyquest.

Motor is an Esskay Outrunner, weight 45 grams, 12 amp ESC.

But getting back to everyone elses concerns about his model. There is one major point being missed here.

It's o.k to spout about how he should use an AXI, or use a Hacker etc etc. Yes, both quality brands. But the Hobby City offer has one major thing going for it over the
AXI and the Hacker. ---- Price!

He can get the Hobby City motor/esc package for $19.95.

How much an AXI 2204/54 in the USA? $64!!!!!!! (Hobby Lobby's price.) And no ESC. Throw in a quality Jetti or CC ESC and you can take his outlay to $US110+

Big difference between that and $US19.95 guys eh?

(Seems everyone likes to spend someone else's money for them.)

So, if his $19.95 outlay, to power an experimental home made profile 3D foamy model does not work, then it's no big deal or strain on the pocket. And he can always cut a bigger model from a sheet of blue foam and try again.

If it does work, then he can upgrade the electrics later.

I think his approach is quite sensible.
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