Petrol Head turning to Electric

[Steve Cornell]

HI all, I've been out of the game for nearly 20 years, having to start from scratch and that includes learning to fly again! You never really lose it I know, but it's been so long that i'm not just rusty, I'm corroded solid!

 

So am looking to take it up again, starting with a basic high wing trainer and entry level radio system. The only thing I'm really unsure about is going electric; I'd far prefer to try this option, but cannot find much about what I need and what the petrol engine/electric motor comparisons are.

 

I have read the various articles here and there in RCME for example, I note there are such things as Li-Po (I thought that was some cosmetic surgery!!) and speed controllers; can anyone please shed some light on these for me as to why I would be better off with Li_Po (is there an alternative?) and in addition, what I would need to fly electric instead of petrol (batteries, speed controllers, whatever else I need)?

 

Furthermore, is telemetry worth having?

 

Your help and advice would be much appreciated!

[Danny Fenton]

welcome Steve, many of us have returned after a long lay off. But its in the blood.

Personally I think you need to just absorb information for a while before you decide. If you are not in a club find one nearby and just go and mingle. There will undoubtedly be some electric models there. Find the owners, and bend their ear, if there is one thing we enjoy its a good chin wag about our models.

Electric and IC are like chalk and cheese, you dont equate one to the other. you can work out what horsepower flew an IC model well, and remember 750 Watts = 1Hp A 120 4 stroke is about 2hp, so an electric version would need around 1500 Watts. but thats a very simplistic view because at half throttle electric will produce half the power an IC at half throttle will not, due to the power curve.

Cheers

Danny

[Pete B]

A welcome from me too, Steve - plenty of returnees like yourself here - any many of us had to find our way through the leccy maze, as well!

 

Finding a club is very good advice and it will accelerate the learning process for sure but it helps to browse the forum for basic advice such as here. You'll get an idea of the composition of an electric model from that thread.

There are a number of high-wing trike u/c trainers about, similar to those used for IC training, and you can either go down that route (either foam or balsa, choice is yours) or just go for a simple job like the V-Trainer, which will get you stirring the sticks again without too many problems.

 

For me, the magic figure to remember is 100W/lb - a good power to weight ratio to aim for for flying the average trainer/sport model. Get an idea of the AUW of the completed model, and multiply that to get the wattage needed. Now, how you achieve that wattage will be the subject of a whole lot of further questions, I'm sure, but the guys here will deliver the goods

 

Now, just find yourself a few quiet evenings..............

 

Pete

 

 

[kc]

A vintage model might suit your purpose at the moment. Some of my clubmates fly electric vintage using cheap motors ( 150 to 250 watt ) and 3S 2200mah Lipos ( equals cheap ) and I intend to do the same. My understanding is that 50 watts per pound is sufficient for vintage, scale and trainers while 100 watt or more per pound is needed for aerobatics

Having an ESC well capable of handling the amps seems the other essential. I have seen a few ESC failures cause crashes when used as power for the Rx so I intend to use a seperate nicad. (actually NiMh nowadays ).

Obviously building light is needed for low power setups, and of course light crashes lighter too.  So a vintage model can easily be built to around 3 to 4 pounds at a reasonably large size, maybe 52 inches span.

 

Telemetry!  thats for NASA, Formula 1 etc and posers. ( well genuine experimenters too I supose but not needed for sport flying - what use is the information? )   It's just one more thing that could go wrong or distract you. 

Edited By kc on 08/12/2011 11:34:37

[Steve Cornell]

Thanks all for the very useful information and the welcomes too! I will certainly be looking at going electric, though have to confess that it is very hard to pull away from IC - the smell of the fuel and exhaust, the distinctive noise, the whole issue still excites me!

 

I am not keen on foam, I've always been a bit of a traditionalist when it comes to airframes and far prefer balsa and ply. Got to admit, I actually enjoying building from scratch more than the actual flying; there's a great sense of achievement seeing all your hours and hard work taking to the air, but then in many ways the moment is over. Either way, I just can't wait to get going again!

[Richard Wood]

Hi Steve & welcome,

Electric flight has improved vastly in recent years & there's never been

a better time to get started. The power available from the latest Lipos

& brushless motors is incredible - & it doesn't have to cost an arm or

a leg.

Don't forget you can still do IC as well - even if it's just for the smell!

 

You'll find plenty of handy info & help around here on electric flight if

you need it.

 

Good luck.

 

 

[Tim Hooper]

Steve,

 

Believe me, you won't have forgotten how to fly - even after all these years! True the tech has moved on leaps and bounds, but the stick-wagglng stays the same....

Leaving the foamies aside, I'd recommend the following set-up;

 

Kyosho Calmato 1400 TR (comes complete with motor, spinner and prop).

Calmato link

 

A couple of hefty 3S 4500Mah li-pos.  You'll only use one at a time!  This size will also avoid carrying any unwanted nose weight.

3S link

 

This model will take you through both A and B certificate levels of performance.

 

Add;

 

60amp ESC (speed controller)

A balance charger

4 channel radio with standard servos

 

This is a known set-up.

 

tim

Edited By Tim Hooper on 08/12/2011 13:04:36

[Steve Hargreaves - Moderator]

Hi Steve & welcome back......it never really leaves you does it?? I bet it will all come back to you in as soon as you have a tranny in your hands!!!

 

I'm curious though....as a self proclaimed Petrolhead (shouldn't that be Methanolhead!!) why do you want to go electric? I agree that electric works really well & there are certainly some advantages (cleanliness is one!!) for me it is all really a bit soulless without that "live fuel" engine at the pointy end.....

[Steve Cornell]

Thanks Richard, Tim and Steve, I guess once it gets into your blood it then goes right into your genes!

Tim, thanks for all the links and tips, will look into that, much appreciated.

Posted by Steve Hargreaves on 08/12/2011 13:31:55:

Hi Steve & welcome back......it never really leaves you does it?? I bet it will all come back to you in as soon as you have a tranny in your hands!!!

 

I'm curious though....as a self proclaimed Petrolhead (shouldn't that be Methanolhead!!) why do you want to go electric? I agree that electric works really well & there are certainly some advantages (cleanliness is one!!) for me it is all really a bit soulless without that "live fuel" engine at the pointy end.....

Edited By Steve Cornell on 08/12/2011 14:17:20

Edited By Steve Cornell on 08/12/2011 14:19:58

Edited By Steve Cornell on 08/12/2011 14:20:24

[steve watkin]

Having been reading this forum for a while I thought it was time to de-lurk!

This combination looks like exactly the thing I'm looking for as a returnee.

I left fixed wing flying about 10 years ago to concentrate on helis but then packed up RC completely about 5 years ago. Moved over to cycling and bikes.

But Christmas had been and gone and my son got me a Blade MCPx which I love. This had generated a desire for a fixed wing model as well to fly at our local E flight field. So going to give this combo a try.

Just one question though, and that is about chargers. What is the recommended AC/DC one to do a good job at a minimum price?

Thanks for enthusing me!!

 

Posted by Tim Hooper on 08/12/2011 13:02:11:

Steve,

 

Believe me, you won't have forgotten how to fly - even after all these years! True the tech has moved on leaps and bounds, but the stick-wagglng stays the same....

Leaving the foamies aside, I'd recommend the following set-up;

 

Kyosho Calmato 1400 TR (comes complete with motor, spinner and prop).

Calmato link

 

A couple of hefty 3S 4500Mah li-pos. You'll only use one at a time! This size will also avoid carrying any unwanted nose weight.

3S link

 

This model will take you through both A and B certificate levels of performance.

 

Add;

 

60amp ESC (speed controller)

A balance charger

4 channel radio with standard servos

 

This is a known set-up.

 

tim

Edited By Tim Hooper on 08/12/2011 13:04:36

Edited By steve watkin on 30/12/2011 22:09:40

[Erfolg]

Ah, another returns. Many of us have done it.

 

I am confident, that what interest you now, in models, will not be the same in just one year.

 

It is best to make decisions that provide options, probably permitting development into areas which you will not be anticipating today.

[Martin Harris - Moderator]

Welcome back - I did much the same a decade ago and found that a few flights was enough to re-learn the basics and do the A test which wasn't around when I was last involved.

 

Rather than jump in to an alien technology, why not stick a fire breather (loads around and not expensive) onto the front of the model and get back into the swing of things. Once you're established again then you can take on board all the preachings and knowledge from the tree huggers and decide if electric is for you. I just prefer i.c. for scale models and nutty models like my Panic...

 

Actually, I - and many others - fly a mixture of both and enjoy either and I would endorse the recommendation of a Calmato if you decide to go electric from the beginning. It's a good trainer but looks good and flies very well.

[steve watkin]

Well it's got to be a fresh start 'cos all the original stuff has been sold or destroyed!

The only thing I have left is a huge vintage model, a Lanzo Record Breaker, and that's not what I want to fly at the moment. So it looks like it's going to be the Calmato route if I can get hold of one. Watch this space!

[John Cole]

If you're going electric then I think most people would recommend a 2.4 GHz radio as these are less affected (than 35 MHz) by the interference generated by the ESC.

[Erfolg]

Much has been made of interference with 35 when using electric power. I have not experienced any issues at all. Not down to electrical noise. Nor have I seen much evidence to indicate an issue.

 

Ducted fans which many say are susceptible to electrical noise, seem to work fine.

 

However if starting from scratch, I would purchase 2.4, whatever my power source, as it is the current standard/state of the art. As has been suggested should be theoretically better than 35 in discrimination with respect to noise, according to those who know (not me).

 

If I had a 35 lying about, I would not hesitate to use that either.

[John Cole]

Erfolg: if you look round the forum you'll see (as I'm sure you know already) many references to NOT extending the ESC to Battery leads as they give off interference (in contrast to the A/C in the ESC to Brushless Motor leads).

 

What interests me is that it's repeated like some kind of religious statement that does not stand up to scrutiny. Why? Because the ESC to motor leads carry chopped DC, not AC. Just like the battery to ESC leads!

 

Steve: and of course DON'T think of buying any BRUSHED motors and ESCs!

[Erfolg]

I hear what you say John, yet I can truthfully say I have never had any issue with interference, particularly from my model, on 35.

 

It could be that in most cases the motor leads are well away from the motor and ESC, and the aerial goes away from the potential source of model generated interference.

 

I do agree, if buying new, it is 2.4. Yet I continue to fly most frequently on 35, with no issues to date. So I have no issues with 35 and electrics. I do think that most of the crashes laid at the door of 35 are the result of pilot error or model, non 35, airframe, component failure. Most being pilot error, as as many 2.4 models go in at my club as 35. The difference is, "Interference, interference, any one else on ****" to (now) "I do no know what happened, it just fell out of the sky".

[Simon Chaddock]

John C

I think you will find the advice not to extend the battery to ESC leads is to protect the ESC capacitor(s) rather than for radio interference. You can extend the leads but the recommendation is to add extra capacitors at intervals along its length. There is apparently a formula for this. I have nevertheless gone up to over 20" without any modification.

Steve

Don't forget that electric is a very gentle power source. There is virtually no vibration and no mess so structures can be built much lighter, an important consideration as even LiPo batteries are a relatively heavy item.

[John Cole]

Simon: thanks, you are right that there are reasons OTHER than interference not to extend the ESC / LiPo leads, but I was really making the point that some of the stories you read as based on completely inaccurate perceptions ("AC in the motor leads").

 

There are 2 reasons for putting in extra caps (& I've seen 220 uF/10 cm advised):

Longer leads will give more ohmic resistance and so increase ripple at the ESC

The "extra load" on the built-in caps will cause them to fail earlier

 

On this basis e.g. Castle Creations sell an add-on, but I've seen postings from a number of electrical engineers dismissing the second point as scaremongering!

[Steve Cornell]

Posted by John Cole on 31/12/2011 16:18:36:

Simon: thanks, you are right that there are reasons OTHER than interference not to extend the ESC / LiPo leads, but I was really making the point that some of the stories you read as based on completely inaccurate perceptions ("AC in the motor leads").

 

There are 2 reasons for putting in extra caps (& I've seen 220 uF/10 cm advised):

Longer leads will give more ohmic resistance and so increase ripple at the ESC

The "extra load" on the built-in caps will cause them to fail earlier

 

On this basis e.g. Castle Creations sell an add-on, but I've seen postings from a number of electrical engineers dismissing the second point as scaremongering!

Edited By Steve Cornell on 03/01/2012 15:20:03

Edited By Steve Cornell on 03/01/2012 15:21:17

[Peter Beeney]

I’ve just latched onto this thread in passing and I’ve noticed that the old motor AC/DC current flow question has come to the fore again. I’ve also had this little discussion in the past! As always, I tend to take the side of the underdog and thus I come down firmly in favour with the school of thought that says the current flowing in the ESC to motor wires is AC. That is, it flows first in one direction and then the other.

I say this with the greatest respect to all, and I think this could be a sensible debate, so to try and make a case I could perhaps do a little drawing to explain my line of reasoning and then it would be perfectly possible for anyone to explain to me where I’m going wrong.

However, I think I should say that before I go any further, I have two measuring instruments, a voltmeter and a clamp meter, that are now like me, quite old, but in their day they were both fully approved for testing some fairly close specifications on new electrical equipment. Both of these report that the current flowing in the motor wires is AC, and specifically not pulsed DC. So that might be a good starting point; and so far no one as been able to satisfactorily tell me why this should be so, if in fact the current is pulsed DC.

I don’t have too many problems with the current in the battery to ESC wires being pulsed DC, though……

PB

[Olly P]

Peter - That may be a bit advanced for discussion in this thread - might be worth starting a purpose one.

 

Olly

[Erfolg]

At a user level, what a brushless motor is of no great issue. I only need to know what is required to make it work, what its limitations are, and what it will do for me.

 

Of interest of course, but not crucial to usage.

[Steve Cornell]

Happy New Year all!

Thanks for all the advice, I've now taken the leap and a four channel trainer has been ordered along with the LiPo batteries - http://www.f1hobbies.com/shop.php?id=4708&level= I was going to go back to building from kit, but to be honest I just want to get back up in the air again, I've got airframes stocked form years ago that I can return to in time, so this sturdy little flyer is for me!

A 6 channel, 2.4GHz radio package (forward thinking for later use!) is being ordered at the end of the week, some excellent deals online.


(Been having posting problems, hence some strange posts above! Appears to be yet another IE9 issue so have gone on to Firefox!)

[Steve Cornell]

Lucky escape!! The trainer I ordered is out of stock and will not be available for at least three to four weeks; I've been offered my money back which i am taking as I just found out the fuselage is foam - I hate foam!!

Whatever happened to trainer kits that you could buy and build, like I did back in 1992???

Edited By Steve Cornell on 04/01/2012 22:14:46