Motor Question (And Maybe Other Stuff)

[stetto]

OK, so I have this electric airplane--Several thoughts are going through my head, not the least of which is "What have I got myself into?", and already I have concerns...

This plane (Laser Models miniLaser 3D) came with a motor--an unspecified motor at that, with a gearbox attached. Can anyone with experience with this particular kit tell me if this motor is really going to be sufficient? I've read reviews of other electrics where the reviewer was dissatisfied with the "reccomended powerplant", and installed an upgrade. I just don't want to go through the maternal pains of creating this bird just to have it stall and rekit because it's underpowered. (Can you tell yet that I know nothing about electrics?)

I picked up a GP C-10 Micro speed controller for it as well-I hope it's one that will work with the thing. I have a box full of micro servos that I got in a trade, so I'm basically good to go.

This is all CTDahles fault... He mentioned that an electric would be a good plane for the parameters of my flying <cough*backyard*cough> field. I hope it doesn't cause nitro-meth withdrawls....

(later, after a keyword search...)
Hmm, ok, I found a review at e-zone, the motor is a speed 300, which tells me little. The author does say it's a blast to fly.

[Ricfly52]

I have seen this thread sitting here awhile, in hopes someone would chime in. But here is my meager beginning knowledge. I have only flow the smaller electrics so far mainly of cost concerns. The biggest thing you have to consider is weight, which means batteries. The biggest percentage of weight may or may not be battery weight depending on what you go with. I would say nicads are out with this small of model. Nimh would work but if you can afford it, go with the li-poly. You have much less weight, and better flight times with them. As far as the motor goes, get everything together and give it a try. One thing nice about a kit of this size is that motors are cheap for it. Basicaly if the model will not take off from the ground then it is way underpowered. That is a good safe test. I personaly hand launched an underpowered model last spring and had to go back to the building board! Have fun!

[stetto]

Thanks for the thoughts ricfly. I kinda forgot I had posted this, what with the future of the nation at stake ...

I haven't had a chance to pour a drop of glue yet, the end of the season upon me and trying to get caught up with paint jobs exterior. I've also acquired a solid-core mahogany door blank to build a workbench with, just need to make room for the shop in the basement.

Don't know much about li-poly (or lithium, for that matter) batteries, but will bone up on them by the time I'm ready for electronical installation.

[ctdahle]

I'm sorry to have exposed you to the idea of e-flying, but I'll tell you, it sure is nice to be able to grab the plane and the kid and go flying and be back home again in under 1/2 an hour whenever the whim strikes.

Even though I am only about five minutes from the "real" flying field, getting any of my glow fueled planes in the air is a half hour process, as is cleaning up afterward, so I don't do it unless I have at least 2-3 hours available for flying, and my 2 year old doesn't have the attention span for that.

However, the process of sizing and specifying motors/gears/props/batteries still has the smell of the black arts for me, so I stick with the manufacturer's recommendations and so far have done fine.

Since I am at nearly 8000 feet, I think any serious power deficit would show up pretty quick.

My Cutie, with a 48" wing uses a Speed 400, geared 2.33 : 1, spinning a 9X6 prop. It runs on 10 cells, or 12 volts, nominally. I think the plane performs about the same as it would if I installed my old OS 15 propped with an 8X4.

The NIMH batteries can give you more duration, but I have found that because the internal resistance of the NIMH cells is higher, my Cutie, at least, is pretty doggy.

At full power setting, I get 15 minutes of doggy flying with the Nimh pack, compared to 6 minutes of pretty zippy flying with the Nicads. THis makes the Nimhs ideal for flight training, but NiMHs are slightly heavier for the same phyically sized cell, so that is a consideration.

Li-Po's are definitely able to deliver more current per unit of weight than anything else, but they are touchy and I haven't been ready to make the plunge with them yet ( the plunge being an electric 4*40 star with a brushless motor and lipo power pack).

Note that if you do go with Li-Po's, your speed controller may need to be reprogrammed to the proper cut off voltage. My current ESCs are not capable of being reprogrammed to match the voltages of Li-Po packs, so I have not yet tried them in my Cutie or my Acropro.

As far as motor size, Speed 200, 300, 400, etc, refers to the size of the motor "can" in millimeters and doesn't have much to do with the actual power, in that a robust speed 400 may be able to deliver the thrust of a .40, or it may be comparable to a .15, depending on how it is built, geared, propped, and batteried.

In my quest to figure this stuff out, I sniff around a lot at e-zone, but frankly I have not had much luck with questions I have posted there. I guess I am happier here where none of us are real e-experts, but at least we all kind of work together to think through the answers.

I'm kind of waiting around for a useable data table that says something like.

"If you want the performance of a BB .46 with an 10x7 prop, try a <motor><gear ratio> <prop><battery><speed controller>"

I have a good sense of what I need to power a particular airplane with a glow motor, and an inventory of motors, props, fuel, etc. that I can swap around by intuition if I want to tweak a particular airplane.

But with the e planes, the gear is expensive and I feel like I really want to "know" what is going to work, and install the right set up based on the numbers rather than cut and try it at the field. Since I don't have an intuitive sense of the numbers, I still feel queasy about stepping outside of the designer's specified power plant.

[jetmex]

Gotta agree with Chris on this one--having the ability to just pull a plane out of the truck and go fly is a great advantage. And without having to drive all the way to the field to boot, which most times is not a drudge at all unless I have the big birds out! I work an odd schedule and often have to fly alone, which just makes the electrics all the more appealing.

Another plus for me is that, being a scale warbird freak, there are subjects modeled electric that no one comes close to trying in glow. Yaks, LaGGs, all kinds of twin engine airplanes, jets--you name it, someone's got a kit. At about the same cost or cheaper than their glow/gas counterparts, especially the jets.

Having said that, it is possible to spend huge amounts of cash on electrics, especially if you're going LiPoly batteries or brushless motors. I've also noticed that the guys who are converting glow kits to electric are spending a lot of cash to do that, so I'm not convinced that that's the way to go. You'll spend as much on a big electric motor as you would for a good glow 2-stroke engine. My interest right now is held by the speed 400 size airplanes, which includes all the Alfa and Flying Styro warbirds, and my next project, the GP electric DC-3.

I'll start a new thread to let you know how the DC-3 is coming.

[stetto]

Yeah well, convenience is a concept I'm not quite comfortable with yet... My addiction to the aromas involved with glow fuel is something I actually like, but I'm willing to give this George Jetson electronical stuff the benefit.

Chris, you'd be surprised how informative you can be... It sure looks like I'll be sticking with niCads, as they seem more dependable (spelled i-n-e-x-s-p-e-n-s-i-v-e) and I'm not a duration flyer, liking short, exciting adrenaline rushes as opposed to long, drawn out consciousness-threatening nail biting marathon flights...

Do electrics do well in colder climes? I know that storing batteries in a refrigerator is often recommended, bur does the cold affect performance positively? I wouldn't mind building some skiis for this bird...

Also, am I a bit ahead of myself with a Lazer? Or are my sub-standard skills with glow models going to be sufficient?

Oh, and to this, Jaime:

Yaks, LaGGs, all kinds of twin engine airplanes, jets--you name it, someone's got a kit.

That wasn't fair at all, and you knew it!!

[jetmex]

Hey Stetto, just trying to nudge ya in the proper direction. Could an electric Musyak be forthcoming....? ;D Or maybe one of these:

www.hobby-lobby.com/yak.htm

[ctdahle]

I have had no problems with the cold. In fact, because the dead of winter tends to be the time of dead calm air, I have logged a tremendous amount of E-flight time with the Cutie between thanksgiving and easter. I find that if the pack is VERY cold (Below 10F.), the power output is slightly reduced at the beginning of the run, but not enough to prevent a nice launch and climb out to cruising altitude. The power seems to pick up as the pack warms up during flight, and I feel like I get longer flights in the cold. This is perhaps because the cold dense air, or maybe my cold fingers just make it FEEL like longer flights.

My e- routine is to slow charge the batteries in the shop, rig the plane and then pack plane and two year old into the truck and head to the park.

At the park, it takes roughly 30 seconds to get the two year old out and busy playing in the snow, and another 30 seconds to activate the ESC on the plane, set the flight timer on my TX, and launch. I hand launch because the plane doesn't roll well on the dry grass or the powder snow, but if there is an ice glaze on top of the snow, I can get nice ROG takeoffs.

I cruise the plane around until the seven minute timer goes off and then I set up to land. At seven minutes I have enough juice left that I get one missed approach and go round. More than that and I need to settle for whereever the plane comes down.

Usually I get the plane down just fine, landing it a good 50 or so feet away because the two year old takes off running as soon as it touches down. THe Cutie is small and light enough that Kyle can easily carry it back to the "flightline". So far, he hasn't fallen on it yet. I'm sure that day will come, but he has such fun "helping" with the plane that I figure if he destroys it, it will just be an excuse to build another.

Anyway, as soon as the plane is retrieved, I pull the spent pack and plunge it into a snow drift to cool. It takes less than a minute to swap in the second pack, and the plane can be airborne again tout-suite.

We repeat the flying routine and when the plane is down, I plunge the second pack into the snow to cool.

If we are going to stay at the park and keep flying, I put the first pack on the charger. I use a Hitec CG?335? which plugs into the cigarette lighter in the truck. It can charge the TX and flight pack simultaneously, but I don't use it for the TX unless I have forgotten to charge it, which rarely happens because of the "Red Scholefield timer routine" that I use in the shop.

If I've packed a third pack, I can go ahead and fly, but generally I just carry two packs because Kyle starts to get restless after two flights and needs some one on one Daddy time.

It takes about 20 minutes for the pack to charge at 3C. I could go faster, but at a higher rate than 3C, the service life of the packs suffers. I spen the 20 minutes playing with Kyle, and then let him choose whether we fly more, or go home. He chooses "Fly Plane Daddy" about 2/3 of the time.

When the first battery is charged, I load it in the plane and put the second, now cooled pack on charge.

At this point you can see why many e-fliers have two chargers. If you have one airplane, two chargers, and three flight packs, you can pretty well fly continuously until you get sick of it, or your TX battery dies. Add a second plane and TX, or just a second TX battery to swap out after 90 minutes of flying, and you could fly all day long as long as the weather holds.

I really enjoy the Cutie, and it's higher performance cousin the AcroPro, but they are expensive little planes and so, for kids and adults that come sniffing around, I have been recommending Hobby Lobby's Mini Telemaster, which they can get into, complete with radio, batteries and flight pack for under 400 bucks.

I like to think that I can fly anything, but even so, I like to explore any new flying field with a trainer to help me find things like final approach landmarks. I've learned that the park where I fly has a weird terrain/air current/wind shear anomaly under some wind conditions. It probably would have killed the faster, hotter AcroPro had I not discovered and probed it with the slower and more forgiving Cutie.

I'd suggest that if you have any qualms about your ability to fly the Laser 3d, you start out with something like the Mini Telemaster, just so you can get your own e-routine figured out and so you can explore the attributes of your backyard flying field with a slower airplane.

Cheers,

[stetto]

--wow--

S' kinda nice just talkin' about flying again...I like the Telemaster idea, I've had a 78" version as a main plane for many years. I see that the price for the kit itself is only $30...Of course it gets hairy after that but I have lots of chargers and stuff, so that would cut the cost...

I am without a TX right now, though, so I guess I should concentrate on picking up a nice 5-channel JR--My 8103 was more than I ever used, so a less expensive model with fewer bells and whistles is in order first off...

[ctdahle]

Yeah, Lets make a point of sticking to flying, and we will all be happy campers!

Jaime's right about the proliferation of e-kits.

Check out www.darehobby.com/ for MANY cool models.

The thing about all these little e-kits is that they are cheap enough that, aside from the cost of all the electrical goodies, you can build four or five of them for the price of a big gas bird.

As soon as I finish remodeling my office, I hope to get back in to building because I have a 12 foot ceiling and that means I can hang up lots of smaller models!