Coverting the fleet from nitro

[Steve_Wright]

Seriously looking at getting away from nitro in my planes, & have some noob questions.

I am looking at Turnigy motors (mainly for a glow bod naming them as an equivilent glow size makes it easy!) Are they any good?

I am currently running .60, .90 & 1.20 sized stuff, an the turnigy motors that are of similar power require multiples of 3s to power them. Can I run lipos in series without issues? That way I could buy multiple 3s lipos and use 1, 2 or 3 depending what motor(?)

On a plane where the battery is a way from the motor, do you have the motor to esc as short as possible and battery to esc whatever it needs to be?

ta

Steve

[Dave Hopkin]

Turnigy Motors are good, as are 4Max/Puffin Motors (and they will always offer good advice on motor size) also good are Eflite (though pricey but also rated in terms of glo engine sizes) - 4max have a useful conversion list too - **LINK**

Yes you can put LiPo's in series to move from 3s to 6s to 9s, (or in parallel to increase capacity) but you may find that you are packing extra weight with multiple batteries compared with a single bigger battery, there is also the faff of creating the wiring loom to think about too - if the length of the wiring gets too long you may need to add extra capacitance in the circuit to smooth ripples out too.

In general terms the shorter the total wiring the better, but if you need to extend the wiring then while some minor losses will happen as long as the capacitance smoothers are in circuit then it shouldn't be an issue

[Stevo]

I shall keep my beady eye on ebay for your engine collection

[Steve_Wright]

TBH mixing 3s & 6s will cover me for all my planes with a max of 2 packs in flight which will keep things simple.

So next one, storage of Li-po. Main reason I haven't used them before is lack of a man den/workshop, thats being sorted as we speak so I can have correct storage & charge area. How are they best stored when not in use? & is a peli case good for transporting them or is a foamed out metal case better?

Lastly, one model is going to require wing off to mount the lipo in the fus, do you put switches in the circuit between battery & esc? Whats the best way to isolate power to the esc when plugs are difficult to get at?

Will be some OS's 4st in .60 .70 .91 & 1.20 flavour on the bay shortly

[Dave Hopkin]

I store and transport mine in a foam lined ali "attache" case thingie, same sort of thing as a XT case - but of flea bay for a tenner

When I charge them I tuck the power leads under a rubber band round the LiPo and leave it out when its been used so I dont get confused!

You can get power switches to go between LiPo and ESC but the ones that cater for high amerage cost a small fortune

the best way to fully isolate power is using an arming token with a female deans plug between battery and ESC mounted against a hole in the fus side where a male deans (with the spades connected together) pushed in and arm the circuit after you have finished mounting the wings etc - you can buy these commercially or make them pretty easily

Otherwise the switch goes on the +ve wire between ESC and RX (or BEC and RX)

 

 

Edited By Dave Hopkin on 12/11/2014 19:39:17

[Allan Bennett]

It's always best to extend the motor leads to the ESC, and keep the ESC to battery leads as short as possible. Too-long battery leads will eventually damage the capacitors that are on the ESC, and eventually then damage the electronic bits. As has been mentioned, if you have no alternative but to extend the ESC battery wires, then adding capacitors across them will eliminate the problem. Castle Creations do a set of capacitors for just that job, but you can do it cheaper by buying individual low-ESR capacitors from Maplin, RS, Farnell, etc.

I believe an arming plug is the only way to prevent the motor running unintentionally, other than disconnecting the battery, for so long as there's power available you never know whether some kind of glitch is going to start things running. I use a Deans Ultra socket and plug, as suggested above, in my Piper Cub where battery access is through the front of the cowl.

I also use various combinations of 3S and 6S batteries to make 3S2P, 6S2P, and 12S packs for various models, as well as using them on their own in other models. I install the necessary connecting wires in the models, rather than having a stand-alone series or parallel harness to transfer between models. That cuts down on connectors.

[eflightray]

You may not like this option but I still feel like saying it.

Don't convert IC models to electric.

Sell them as going concerns, and buy or build models specifically for electric power.

My logic ?, you will have much better flying models as they will be lighter, need less power, require a lighter motor and battery pack. All a saving in weight, energy, and cost.

If you believe heavier planes fly better, stick with IC power.

 

P.S. I've been flying electric power for the past 30+ years, and model building for near 60 years, I do not know everything, but have enough experience to find lighter planes fly better.

 

Edited By eflightray neath on 12/11/2014 19:55:47

[Steve_Wright]

the best way to fully isolate power is using an arming token with a female deans plug between battery and ESC mounted against a hole in the fus side where a male deans (with the spades connected together) pushed in and arm the circuit after you have finished mounting the wings etc - you can buy these commercially or make them pretty easily

I think I understand what you meant with this, can you point me at one you can buy so I can see exactly?

Ta

[Dave Hopkin]

Arming plug...... MUCH cheaper than I thought, last time I googled them HK didnt do them

 

four of your english pounds and still have change for a bag of chips!

 

**LINK**

 

Or

 

http://www.schumacher-products.com/ArmSafe-Brochure-RevA.pdf

 

Also dont forget to program a Throttle Cut switch on your TX...... belt and braces!!!!

Edited By Dave Hopkin on 12/11/2014 23:25:00

[Simon Chaddock]

Steve

I would have to agree with eflightray neath that in principle converting an IC plane to electric will not give the best result. It certainly can be done but is not an ideal solution.

IC planes have to built heavier than electric to withstand the substantial vibration from a single cylinder engine which an electric motor simply does not have.

Electric propulsion is intrinsically heavier than IC as it has to carry all its energy in the battery whereas IC gets about half from the oxygen in the air so every bit of weight saved gives more performance or allows a bigger battery.

Finally there is no need for any heavy fuel proof protection.

[Steve_Wright]

Thanks for the links Dave.

I have weighed the IC gear (motor, servo, fuel tank, on board glow & pipework) in my planes and they are heavier than electric gear I am putting in, yes the fuel will burn off so at the end of a flight electric ends up a bit heavier. I am not getting rid of the planes I like just because they are not optomised for electric. Anyway this thread isn't about whather or not to convert, that choice has been made.

[iqon]

have one of these ESC with switch and works ok

[Pete B]

I've converted several IC-designed ARTF models and in each case the result has been a lower AUW than specified. The main drawback has been battery fitting - unless you create a hatch/bay with access for changing the pack, there is no option but to remove the wing to change the packs, which is a pain.

I don't believe you will be compromising on performance either - mine have flown exceptionally well judging by those who've seen them fly and they compare favourably with the IC version. That's not to mention the ease, convenience, reliability and cleanliness of leccy....

I'm now building a couple of models which will run on 8S and so far, up to 6S, I haven't found too much of a problem with the spark issue, although 6S does create a spark with my Deans arming sockets, which I fit inline with the +wire.

I've ordered some XT90-S Anti-Spark Connectors to use as arming sockets for 6S and up for the forthcoming models. My packs are all XT60s so, by using these connectors only as the arming socket, there's no need for adaptor leads etc.

Pete

[Steve_Wright]

just been to the LMS for a soldering iron, picked up a nice 100w one witha big wide chisel end, no more struggling with my rubbish 25w one. Of to practice on my Hyper 7 buggy which is getting a brushless conversion too

[Andy48]

Posted by iqon on 13/11/2014 09:07:54:

have one of these ESC with switch and works ok

Probably will, but not as safe as an arming plug.

[Allan Bennett]

Like Pete B, I've converted several -- maybe a dozen -- of my glow models to electric, and they've all ended up lighter than when they were glow powered, including the battery in the case of the electric version, and a tank of fuel and a receiver battery for the glow version. So I don't really agree with the advice to sell up and start again.

A couple of my ex-1.20 size glow models are now running on 12S and 2000+ watts. The spark on connecting is not a problem because my ESCs came with anti-spark bypass resistors. My flight durations are in excess of 15 minutes, the same as when they were glow powered.

During the conversions I do take whatever steps are practical to lighten things a bit. In the case of my Flair Magnatilla, for instance, it was replacing the Solartex covering with Solite

[Steve_Wright]

Okay then. As my first effort in converting the fleet I have a BH Travelair, roughly 6lb in weight, currently a bit over engined with an OS 70 fs (sometimes long grass on my field, helps with takeoff)

I am thinking a Turnigy G46 LINK with suitable ESC & 4s lipo. Motor is 40amp max, what sort of sized prop should I be looking at? Is there a way of reliably working out the amps for a prop size ?

[Allan Bennett]

That looks to me like it should do the job, with 600 watts potentially available with a 4S LiPo. If you scroll down in your LINK, you'll see in the reviews that someone tried a 13x6 prop and got only 400 watts at 28 amps, so I would suggest at least a 14x7 for starters, to try and get close to the motor's continuous rating of 40A.

I find that WebOCalc is a very simple program for predicting motor amps, watts, and general performance. Click on the "Software" tab at the left. But, whatever advice and information you use, always check your actual amps at full throttle with a wattmeter because each motor and prop may be slightly different.

[fly boy3]

Hi Steve, I think you will get many differing stories on this one. I must agree with Eflightray Neath. Even if your model is lighter with electric gear in stead of ic, put the gear in a similar sized model designed for electric and it will be even lighter. As Ray says lighter models fly better. Cheers FB3

[Steve_Wright]

Thats always going to be the case with any aircraft. I am not ditching my current stuff. Future ones will be aimed at electric

[Steve_Wright]

Posted by Allan Bennett on 18/11/2014 20:09:27:

That looks to me like it should do the job, with 600 watts potentially available with a 4S LiPo. If you scroll down in your LINK, you'll see in the reviews that someone tried a 13x6 prop and got only 400 watts at 28 amps, so I would suggest at least a 14x7 for starters, to try and get close to the motor's continuous rating of 40A.

I find that WebOCalc is a very simple program for predicting motor amps, watts, and general performance. Click on the "Software" tab at the left. But, whatever advice and information you use, always check your actual amps at full throttle with a wattmeter because each motor and prop may be slightly different.

Thanks for that link. So in my TravelAir on a 12x10 should pull 38Amps. How close should you aim to the motors peak amps?

[Allan Bennett]

Posted by Steve_Wright on 18/11/2014 20:50:08:

Thanks for that link. So in my TravelAir on a 12x10 should pull 38Amps. How close should you aim to the motors peak amps?

It depends on the motor's reputation, and your flying style. With my AXI motors I usually aim to be just over their quoted continuous maximum amps at full throttle because after take off I usually fly at half throttle and I know that AXIs specs are genuine ones, not just advertising hype.

By the way, 12x10 is a bit "coarse" for my liking -- if you go for larger diameter and less pitch you'll get better acceleration, rather than top speed, and the amps will be about the same.  If you've got a problem with prop clearance, you could look for a motor (if you haven't already bought it) with a higher Kv, which will spin faster and therefore use a smaller prop for the same power.

Edited By Allan Bennett on 19/11/2014 08:33:09