trpastor

Hey Guys-
I went to horizon's site which has this info page
http://www.horizonhobby.com/ProdInfo...equirement.pdf

I'm going to get this plane
http://www.horizonhobby.com/Products...ProdID=EFL2600

I don't have a lot to spend on it right now, so I want to get motor/esc/battery from hobbyking

According to their info the plane weighs 1lb

1x200w (for full 3d ability) = 200w of power I need

Looking at the 400 920kv (which is what they recommend) and a 3 cell lipo (3x3.3v=9.9V)
9.9v x 10A continuous = 99 watts
9.9v x 13A burst = 128 watts.

According to their specifications, this is NOT enough to 3D????


What am I doing wrong. Also, what do the KV determine? and how do I prop it.

The most similar motor I can find on Hobby king is this one. It weighs about the same, and seems to have similar stats (the KV is only 130 higher, and the prop recommendations are different)

http://www.hobbycity.com/hobbycity/s...less_Outrunner


This one is
9.9 x 12 = 118
9x9 x 14 138

Better, but still not enough? ??

THEN, how the heck to I figure out how to correctly prop it for 3D flying?

I guess I just get an ESC that handles the amps... so a 20AMP esc

thanks for your help

playntraffic

Most motor manufacturers post test data with different props. The prop load will determine the amps that are generated. Amps x voltage = watts.

The pitch and size of the prop will also determine the thrust. A higher KV is designed to spin a smaller prop faster. 900 - 1000kv is about right for a 3d plane. They will spin larger diameter props for the minimum amout of amps. If you put the same 11x7 prop on a 1300kv the motor will burn up and fry very quickly.

Here is another motor option from hobby city.
http://www.hobbycity.com/hobbycity/s..._17A_Outrunner
Read the reviews, most are helpful for amps, thrust, and prop recommendations.

The rated 17amps is the max continous. Get an ESC that is at least 25 amps.

Get a few 12x6 GWS props and a few 25c-30c 1300mah batteries and you are all set.

Now that all of that is said, have you considered a foamy? More durable and lighter. DWFoamies has some good ones, ChargerRC is another good one. Have fun.

trpastor

I'd like to fly it outside. I guess the edge will be able to handle a little more wind, right?

So - do you think the one I picked is not a good fit?

I really don't understand all these equations. Is there a site that has more info? Are my numbres not correct?

blhollo2

My Feedback: (278)

i have no idea...im scared too

playntraffic

Neither plane is good for winds past 6mph. Just no fun trying to fly when your plane is bouncing all over the place.

The foamies are easier to fix. You can repair a foamie with a hot glue gun and be ready for action in minutes. A balsa and covered plane takes a little longer

I like to practice on a foamie and apply what I learn to my larger planes.

I don't mess with wattage formulas much and really am not concerned with the wattage of my motors. Here's why, a cheap brushless motor will spin a 8x6 prop at high amps (restrictive design) and pull 200watts but be absolute crap for a 3d plane. Another brushless motor by AXI or Hacker will turn a 12x6 prop at the same amps or lower and pull the snot out of the same plane.

Look for the same things you look for in your glow or gas planes. The pitch speed and thrust of the prop. Most motor manufacturer's list prop data. Here's an example:
http://www.innov8tivedesigns.com/pro...products_id=36

You are looking for a 2:1 thrust (minumum) and a decent pitch speed. Pitch speed is not as important on profile planes because of the thick wing and you are flying on the prop. See the 10x6 GWS HD prop at 10.5 volts? That is running 33 oz of thrust at 17amps on a 3 cell lipo. Now pick up a esc that is rated for more than 17 amps , some GWS 10x6 props, and get a lipo battery that can handle 17 amp discharge.

I would not run an 18amp esc or even a 20 amp. 25amp esc give a good comfort level of protection.

Different KV motors have different "sweet spots" . They are more efficent with different props. Higher KV motors run best at higher rpm with smaller props (speed). Lower KV motors turn slower with more torque for larger props. Different manufacturer's motors with the same KV can net different results because of the quality of magnets, wires, design, or manufacturing.

opjose

3 Cell Lipo = 3.7 x 3 = 11.1v nominal 12v+ initial.

11.1v x 13a burst = 144 watts

As playntraffic mentioned you want a different motor, esc and prop combo capable of putting out more watts. This will also add a bit of weight and reduce flight times.

-

While I love foamies, the ability to repair them is WAAAY over-rated, as is their capacity to withstand abuse.

Give me a balsa plane and after a crash I'll have it looking as good as new in no time, especially one of the type that you are considering.

Foamies get beat up quite easily and you are forced to buy repair parts, as opposed to merely using stock balsa available at any LHS.

-

We fly the plane you are looking at in 10mph+ winds all the time. It does just fine in them, but this is highly dependant upon your skill level.

If you fear 10mph+ winds, then you need to get out and practice with a heavier plane in higher windws until it becomes second nature to you. Once crabbing to landings, etc. becomes easy you'll not worry about winds in this range.

Actually this plane is a LOT of fun in a steady 8-10mph breeze, as you can chop the throttle off, and the plane will act like a glider. It also harriers quite nicely into the wind.


KV determines how fast the motor will spin PER VOLT with no load on the motor ( e.g. no prop ) it is an ideal rating of the rotation rate of the motor.

Loosely defined: The prop determines how much energy the motor will require, and that in turn determines both the size of the motor you are looking for and the size of the associated battery and ESC.

An easy way of doing all this is first to determine what you want your power system to draw in WATTS.

Always assume that the stated weight will be a bit optimistic, so you'll want about 220 watts burst or so.

Find a motor that can sustain 220 watts and what prop is recommended to get that output from the motor.

Divide the wattage by the rated voltage output from the battery pack and you'll get the minimum rating for the ESC.

So 220 / 11.1 = 19.2A then allow a margin for safety, so a 25A ESC would be good.

You also now know that the battery will have to be capable of sustaining a burst draw of 20A.

So you'll be able to use a 20C 1000mAh 3S LiPo at a minimum, or a higher capacity pack. You can also trade some "C" rating in for higher capacity... e.g. a 15C 1500mAH pack will also work... though I recommend sticking with 20C or better batteries so that you can use those packs on other planes later.


Don't be so concerned with matching the specs of an existing or recommended motor.

Instead opt for the motor that gives you the watts you are looking for, but is not TOO far off on the weight.

Even an ounce weight difference is not going to make that dramatic of an effect on the flight characteristics of the plane.
Often you can trade one thing off for another, but don't go overboard on it.

As playntraffic mentioned, you'll be shooting for a KV rating somewhere around 880 - 1100kv.

The lower you go the wider and higher pitch the prop you'll need to use, while the higher the KV the smaller the diameter and lower the pitch you'll need to get the same performance.

beau0090_99

Most of the info above I agree with, but I think that 220 watts for this plane is way overkill. Even if you want to do 3D, you don't need a 2:1 thrust to weight ratio unless you want the plane to accelerate vertically at the rate of gravity. I have heard it said that 150W/pound for 3D is sufficient, and this is input watts, just simple Voltage times Current. Check out the Turnigy SK2826-1000 motor. Prop it with an APC 10x5E and run a 20-25A ESC to it with a 3S Battery around 1500mah and 15-20 C and you will be pulling about 15Amps WOT. This will give you about 25 oz thrust and should pull that thing out of sight no problem.
Good luck with your search.
Curtis

opjose

You have to allow for exagerated claims from the manufacturers.

The 220 watt motors come in at around 170 watts or so max, which is not that much of overkill for a 3D plane.

You want a good bit of excess power to be able to quickly pull a plane out of heading to the ground.

Though I have NO problems with the motor you are suggesting as well, and it will probably be a good match.

beau0090_99

That's a good point. All of the Hobbycity/Hobbyking motors are a bit over exagerated on their wattage specs. The one I listed is listed at 245W. It is rated between 2 and 4 Cells lipo, so I used the 245W and divided by 4 cells to see what the limit should be and it is about 16.5Amps. So even at 3Cells, I figure I will try to stay under 16.5Amps, so that would give about 185W which if the plane weight is accurate, I think would make that thing boogie.
This is a lot of uncharted water here. I would recommend checking out the RCGroups website and talk to Dr. Kiwi over there. I have gotten a lot of good info from him. There is even a thread that I have used to take a $3 multi-meter from Harbor Freight and modify it to give you up to 100 or 200Amps current sensing, which is good to test your setup.
Curtis

opjose

Heh, much like most manufacturers. A very few do better though.

jbaniqued

I have two Turnigy D-2826/10 motors.  The info sheet provided with the motor indicates a 40A ESC is required.  The Max power for the motor is rated at 205 watts.  205 watts with a 3 cell LIPO calculates to 18.47A.  This would imply, to me, that a 25A ESC should be all that is required (for simple pattern/spot flying.  Why does the manufacturer recommend such a high amp ESC for this motor.  For info purposes, I will be putting two of these motors on a Multiplex Twinstar II, flying weight of 3.3 lbs.  I had planned to use two Turnigy 25A ESC, one on each motor and turn 7X4 e counter-rotating props.  I am new to this electric flying so please bear with what may seem to be basic questions.  I really appreciate any help, even just pointing me to a site where I can learn more about motor/esc/prop determination.

opjose

You should be fine with a 25A ESC.

HK's 40A ESC's are not much bigger than a normal 20-30A ESC, and the price difference is small, so it doesn't surprise me that they recommend a 40A ESC.

Remember though 11.1v is the normal operating voltage of a LiPo pack.

When you first start off the voltage may be as high as 13-14v. The voltage drops after the first minute of flying down to the 11v range.

So 14v x 21A = 294 watts

HK is right to opt for a worst case situation.

jbaniqued

opjose - Thank you for the information. It is very helpful. I'll try flying the 25A ESCs and see what happens. If and when I try to get a little more aggressive in flying the Twinstar II, I will watch the amp usage and more to a higher rated ESC if called for. Thanks again.

DenverJayhawk

my EPP fusion bird from DW FOamies withstood abuse that my balsa models could only dream of. And my depron foamies are much easier to repair than balsa. I just bring CA to the field and do repairs on site instead of packing up all the splinters and taking them back home and pulling out the dremmel to fabricate new balsa parts.

OP - check out quantum hobby's website for ZTW ESCs. Very good ESCs and shipped locally in the US and a fair price. These are my default brand of ESCs when I'm setting up a new bird. For the size motor you'll need, check out BPhobbies or valuehobby.com

opjose

Re: Foamies vs Balsa

Sorry DenverJayhawk but I disagree.

If you are LUCKY and a foamy breaks along an easy to repair line, then you can easily glue them back together.

Unfortunately Murphy does not like to be kind to people....


More often than not you tend to loose the small "beads" that make up the foam, and parts of your jigsaw puzzle go drifting off into the wind.

The end result is that the so-called "easy" repair becomes highly problematic.

Foamies tend to ding quite easily, picking up gouges, scratches, breaks and marring that makes new foam planes quickly look quite ugly.


With a wood plane, even with severe crashes, I can easily fabricate any missing or broken parts out of ply or balsa obtained from a craft or hobby shop.

The replacement parts are often stronger than the original. A bit of covering and the plane looks like or better than new without dings and scratches.


I've a bunch of foamies, but easier to repair? Only when you litterally get a "lucky break".

In contrast my .60 Big Stik has had the wings ripped off in a full throttle dive into the ground during a fun-fly, the fuselage broken in six different places, wheels ripped off, firewall broken out, etc. etc. etc.

One evening of work and the plane looks better than new... so much so that I was asked if I had just purchased it.

When my foamies sustain more than minor injuries, I'm all too often forced to buy a whole new airframe... and of course when the intakes of my EDF's get compressed... ugh.

DenverJayhawk

the only foamie i've had that was a pain to repair was the mass produced stuff from Horizon that uses this so called Z-Foam stuff and when that broke, it did bead and crumble apart as you describe. That was a PITA to fix. But my Depron birds from DW Foamies have clean breaks. The depron is so stiff in fact, that it snaps with no splintering or beading at all. It's a razor clean fracture that is glued back in place with a little CA and kicker in 20 seconds.

This weekend, i dumb thumbed my DW Juka (depron foam) in the wind and broke off an entire section of the nose and landing gear. A little CA and kicker and i was back in the air in 2 mins. My EPP foam bird has never even broken in a crash. It's beat up and warped, etc but it never broke and I pile drove that thing to the ground hard several times.

opjose

We'll talk after you've had a few more crashes.... heh.

I have some pretty big Foamies too, like the Fly-Fly F-100 and the Carbon-Z...

They are a lot of fun and trivally easy to put together... but I still prefer my wood planes over foamies.

My "woodies" are always in good shope.... though sometimes it is amazing to see the beat up flyers people bring out.

With wood I can ALWAYS fix things, the only question is the amount of time I wish to invest in the process.

With foamies you are married to the vendor's ability to supply parts.

DenverJayhawk

it's funny, because i love my balsa models too and i'll always have a few in the hangar ready to go. But for a quick run to the park for 15 mins, you can't beat an electric foamie in my opinion, especially a stiff Depron bird that flies like a 33%-er. Not proud to say that I've crashed a lot, and every time, gluing foam back together was easier and less time consuming than fabricating new parts out of balsa. At the point when the foam can't be glued back together, i just pitch it and spend $69-89 bucks on a new kit.

AltaTed

How does one repair a foamie when the foam is covered by a plastic finish and the break in the wing shows as a bend but it's not separated ?

Alta Ted

opjose

Like my Typhoon 2.... I had the same problem.

You either have to cut open or lift the plastic carefully, fix the crack and re-glue... or you buy a new part.

For me this is a case in point why "woodies" are better for repairs.

AltaTed

ESC size selection. I decided to just standardize on 40A ESC's formy smaller planes and as said before, there is little cost difference. When you set up the ESC with any motor, you go through a setup proceedure so the ESC is matched to the motor. Since doing this I have not lost a single ESC and have never burned out a motor.Is there any downside to this other than cost beinga couple of bucks more ? It's sure cost me less sinceI stopped ESC failures and I don't have to wait for a new one to arrive if a smaller one fails.I had experianced too many of these smaller onesfailing before doing this.



Alta Ted

AltaTed

I sure agree on repair that woodies is far less difficult in the long run. I have several planes now that started out as foamies and are now hybrid combinations using old foamies parts and woodie components when the foamie parts that broke were not salvagable. It's kind of fun to recycle the parts and end up with some strange birds thay fly just fine.

Alta Ted

opjose

I agree. Many times the difference in weight and size is so small that there is little reason to go with the smaller ESC.

I've only had one tiny EDF where I had to use a small 20A ESC as nothing else would fit, but that was the exception to the rule.