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Possibly going all electric, which motors should I use?

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Foxfan24/08/2019 20:56:11
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825 forum posts
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Due to the costs of even second hand engines and particularly four strokes (and even more so, small four strokes). I am seriously considering going all electric.

I love the sound and smell of engines, but the cost of fuel is also a consideration. Batteries will get better and cheaper and I can tolerate the badinage at the club, which is staunchly IC and Gawd bless it for that, but I am tired of looking for affordable engines. I have a few, which I could sell to finance the change.

However, I wouldn't know any kind of equivalency rule of thumb for the electric counterparts. Size, Kv, prop size, battery size, etc.

I have a Great Planes Electri-Cub which I was going to put an OS 10 in. A DB Mascot, for which I'd lined up my Enya 35 and plans to make a Skyfarer, which is the one that triggered all this as it asks for a 20-25 sized 4 stroke, which are crazy money.

I am essentially a 4-5 foot span kind of bloke, smaller if poss and a couple of three foot wings (RC converted from, C/L plans) are in the plans drawer, which would also need 20 size IC engines. Being a lover of the smaller 'plane I am a perfect candidate for the electric world, too. A powered glider to do some soaring appeals as well.

So, can anyone help with the info for the electrics if I make this change?

Many thanks,

Martin

2.4g Shaun24/08/2019 21:57:22
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21 forum posts

In my mind this is an easy one, George at 4-Max. He's tested and produced real world data on over 800 set ups so you know exactly are what you are getting.

Plus you'll be supporting a UK model shop.

Shaun

Trevor Crook24/08/2019 22:06:10
849 forum posts
65 photos

Bit of a learning curve for you, Foxfan. A "must have" is a wattmeter, to check your setup is giving the right amount of power. For your sport models, aim for around 100W/lb of model weight for good performance.

My rough guesses for your models, which I am not too familiar with, are as follows:

Electri-Cub 900-1000kV motor, 10x6 prop, 30A esc, 3s 1300-2200 lipo.

Skyfarer, 900-1000kV motor, 11x7 prop, 40A esc, 3s 2200 lipo

Mascot, 750-800kV motor, 11x7 prop, 50A esc, 4s 2200-3000 lipo

These estimates are purely from my experience, others may provide more scientific data!

Interesting comment on your club, both clubs I am in are now 80-90% electric, but we are in the noise sensitive south-east. Many other advantages of electric, which is why I "converted" about 10 years ago. Fiddling with model engines was never much of the hobby for me, though, I'm more a flyer and sometime builder.

Good luck with the new power trains.

PatMc24/08/2019 22:54:25
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In general I agree with Trevor, except for the Watts/lb figure. In my experience 60 - 80 Watts/lb is plenty power for the type of models you've mentioned.

It's also a good (economic) idea to standardise as far as possible in battery voltage & capacity. For the type of model you have mentioned 3s 2200mAH batteries should be fine for most 10 - 25 ic size models & 4s 2650 - 3000 for 35 - 40.

Foxfan25/08/2019 00:17:10
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Interesting, gents, thanks. Maybe a call to 4 Max is in order. I keep seeing him mentioned as a knowledgeable chap.

3S 2200 seems to be the standard kind of battery these days. I have one already from my boat efforts. Maybe that's the one to use for the Cub to start with.

Thanks again,

Martin

Foxfan25/08/2019 00:25:31
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The Skyfarer is smaller than the Cub or the Mascot. Only 4 ft-6 span and intended for 20-25 four strokes, so I assume .15 2 strokes. Though what that means in terms of motor choice I don't know. The OS 10 seems to be thought of as a bit of a screamer, but on an 8x4 prop. So, a 900-1000Kv motor on a 3S will spin a 10x6? How does Kv tie up with a motor's physical size and how is that expressed?

Martin

Nigel R25/08/2019 07:49:07
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3058 forum posts
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Just my take - Don't expect to save money by going electric.

Cuban825/08/2019 08:46:12
2714 forum posts
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I can understand being forced to go electric where there might be noise problems or other sundry issues that perhaps, might affect ones operation of IC, but if you appreciate the merits of engines but are prepared to give them up over cost grounds alone, in my opinion, you'd be making a big mistake.

The pleasure of running IC is part of the attraction for me. Yes, I have several electric models for convenience when I only have an hour or so to go flying during the week, but the weekend and a full days flying on Sunday means IC and the time to enjoy the running and sound of the engines.

Fuelling up, starting, the model coming to life when warming up and feeling the engine's heartbeat through the airframe, even cleaning down is all part of the experience - no so much cleaning with the lower oil content fuel BTW. Sorry, but a reasonably sized warbird sounds and feels dead when powered by an electric motor to my ears and sensibilities.

I don't find fuel expensive - £17 for a gallon of Model Technics Laser mix at the shows - and if you keep an eye on BMFA classifieds some real bargains are still available, but you have to watch the site and be quick, especially now with ASP etc out of production.

By all means try electric, but don't sell your engines just yetwink ...............nose, face, cutting off, and all that laugh

Enjoy whatever you decide to do.yes

Peter Miller25/08/2019 10:29:55
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10168 forum posts
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Like Foxfan. I was a dedicated ic man but have moved over to electric power, mainly becase luuging the gear across to our field is getting tiring at my age.

I like the same sort of models that Foxfan likes and I agree with him on many points.

Basically I pick up the phone to George at 4-Max and say, it has such and such a span and wing area. It weighs so much it is going to be aerobatic. WHAT do I need, George tells me and that is what I fit and it works perfectly.

I can also say that I am thoroughly enjoying flying electric power. I got a little micky taking but that is all part of the banter and fun.

RC Plane Flyer25/08/2019 12:20:50
637 forum posts
16 photos

I have to agree with Nigel R. I get more fun out of a £19 gallon of Laser fuel than an equivilant lipo battery

It is horses for courses and we all have our own opinion

I do have an Easy Street and electric pylon racer both fun to fly but time restricted

Don Fry25/08/2019 12:54:59
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3920 forum posts
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Foxfan, the DB Mascot with a 35 is a good setup, and you own it. And it is all you need to learn on. The other models can wait until you save some cash.

Buying a wattmeter, motor, speed controller, battery charger, half a dozen batteries.....ain't cheap.

or a gallon of fuel good for 75? flights on a 35, and it's good to go at any time.

Foxfan25/08/2019 13:01:17
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825 forum posts
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That's twice now, Laser fuel has been mentioned, but whilst I would kill for a laser 45, I couldn't justify anything bigger and probably not even a tiddler as I don't have space for huge aircraft and I really don't actually like them!

Yes I love the sound and smell, but not the fiddling if they don't run right.

Nigel, I can't see electric, THESE DAYS, being expensive for my kind of model. I'm sure a motor and the inevitable 3S 2200 "Mars Bar" would power the Skyfarer easily and cheaply. As to time aloft? I've read some angry reposts to that accusation claiming the opposite. Maybe the batteries are getting better AND cheaper.

I went to our club's Fly-in today. It turned out to be the committee members as they'd organised it. Everyone else had gone to the Nats or maybe didn't want to fly with the committee , but a lot of vintage style Junior 60s, Majestic Majors (I thought they were Daimlers) and Super 60s, even a Galahad with a big PAW in it. And of course a Laser 80 in a Majestic, puttering like an old Royal Enfield on tickover. Flown from a chair!

Upshot is I still don't know what to do, unless, of course, the guys who went to the Nats come back with some deals and can release their small 4 strokes they have tucked away. That would certainly tempt me to buy that Laser fuel, even if I can't afford a Laser.

I also flew a tiny foam glider with the smallest Brushless I ever saw on the back and it flew in the calm air beautifully. I might have a bash at R/Cing my one.

So, maybe a mixture is still the answer.

Cuban 8, I will never have a "Warbird". I detest all militaria and most of what you describe as an essential of the hobby I can happily leave well alone. I can only manage 2-3 hours on a Sunday and a Tuesday, so the day long sojourn is not in my remit. I found all but three engines' noise today faintly annoying actually. OK, the diesel, the Laser and the weirdly 4 stroking 25 (of unknown make) were the exceptions and very pleasant and the diesel smell was sheer bliss. And at that price per litre, so it should be!

Thanks for your inputs, gents.

Martin

Edited By Foxfan on 25/08/2019 13:03:13

Foxfan25/08/2019 13:10:26
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825 forum posts
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Don, our posts crossed.

You make a very good and typically succinct point!

I do have some electric stuff already that I had when i was a boaty person, so all I would need would be a few extra batteries and ESCs. I have 2 electric 'planes currently and a third built but waiting for me to be a decent flyer.

I will use up my fuel learning on the Mascot and then re-assess, I think.

Martin

eflightray25/08/2019 14:45:21
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575 forum posts
128 photos

Just my opinion, but don't bother converting IC power models to electric. You end up with a compromise.

Go straight for models designed for electric power only, and if you're a builder, consider some of the many fun, and profile scale models, designed and built using Depron foam, (it's also much cheaper than balsa).

Forget the, "It has to be oily, noisy, and made with balsa" stuck in the past club members. Show them what can be achieved with electric power.

Ray. smiley

(60+ years of building and flying, 30 with IC, 30 with electric, I wouldn't go back to IC) cheeky

Edited By eflightray on 25/08/2019 14:46:01

Foxfan25/08/2019 16:16:43
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Ray,I already have a Skystreak 32, which I converted from balsa to Depron, buying some of the magic board from SLEC a few weeks ago ( I live a pleasant toodle away from there). That will be electric as I designed it for that from the beginning. The Electri-Cub came with an old brushed behemoth, which I'll keep for one of my boats, but although allegedly designed for electric, was also flown on an OS 10, which I have. The Mascot was built for an IC engine, but I see no reason why it couldn't be converted. Power, after all, is power, from whencever it comes. But it would be a faff to redo the business end for an electric motor and I do have an Enya 35 for it. I think I may well just carry on with what I have and for anything new, go electric as it would definitely be cheaper. I would love to get the PAW and my ancient ED Racer aloft too, but only if I can make diesel fuel for a fraction of the ridiculous cost of it commercially.

I can fend off the very IC slanted membership of the club. I notice they don't barrack one particular member who is such a superb flyer they stand in awe of him, even though most of his current fleet are all RTR foamies. My wish is only to fly low, slow and smooth and Bernard does just that all the time. It's a real delight to see. 3D is anathema to me, clever though I'm sure it is. I could no more own an Edge than a Focke-Wulf!

Cheers,

Martin

Tom Sharp 225/08/2019 21:03:00
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3515 forum posts
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Electric flyers get much better at landing than IC flyers because they have to land more often per flying session.

Foxfan25/08/2019 21:46:57
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825 forum posts
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Haha. I hear that suggestion quite a bit, but I also see others who angrily refute the assertion. I think that's a case of "You may say that...I couldn't possibly comment". But I don't necessarily see any advantage to overly long flights and often think, "OK, come down now, it's getting boring". Plus, because of home considerations, I can only give 2 or three hours to it a couple of times a week. In that time, I have to let others fly, I need to have a chat and make/drink coffee in the hut, so lengths of flight are not a problem for me. I am happy to do a few circuits and just practice manoeuvres and go home pleased.

It's that or yachts! And model boaters are miserable old sods in my experience. I much prefer the banter at the flying club on a Sunday morning, although today the fun guys had gone to the Nats.

Martin

Tom Sharp 225/08/2019 22:03:36
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3515 forum posts
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I believe model boat men have reason to be miserable, tramping about in all that goose manure.

Anthony Hill at 'All Electric' is another good man to talk to about electric flight. They have been specialising in electric flight for many years.

Trevor Crook25/08/2019 22:16:41
849 forum posts
65 photos

Don't understand the carping about flying time. During my 30 years of flying ic I typically flew for 8-10 minutes before it felt it was time to land, and that's the kind of duration I get from my leccy models.

An older club member used to pull my leg about "landing again" as he puttered away for half an hour with his vintage model, but I'm afraid that would send me to sleep.

To pick up on points others have made regarding your original question, I would agree with Pat that 100W/lb is generous for a sport model, and a bit less would be fine. I'd also agree it's good to have a "standard" battery size, although I haven't acheived that with my 2s 1000 - 6s 3000 fleet!

I've got several models intended for i.c. that fly fine with electric. The main advantage with specific ep designs is they allow for battery positioning and access, but I've never had a problem sorting that with my "conversions".

Foxfan25/08/2019 22:17:19
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825 forum posts
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Yep, it's a disgrace how much poo those Sheringham gooses put down on the prom<G>

I'll look up All electric, thanks.

Martin

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