Leccy Fun Fighter

[Danny Fenton]

I am looking at building a light-weight fun fighter sized model, (32" ish) no wheels, hand launch. What is the cheapest leccy motor/battery/ESC set-up that should get it flying around? Not worried too much about startling performance at first, just want to go park flying. So perhaps brushed motor with NiCd.

[Jonathan Lewzey]

I'm building two fighters at the moment, the P-40 plan from RCM&E (see the image gallery) and a Tony Nijhuis Zero. The P-40 is around a speed 400 whereas the Zero uses an Axi Brushless. Either of these designs are great and I am particularly pleased with the P-40 which is nearly completed. You could also try the Mainly Models Fun fighters (foam kits) from their shop in hitchen, the Cambrian fun fighters from ATS maineline or the really tiny 1/16 and 1/20 scale foam fighters from green air designs (www.greenairdesigns.com) I saw their mosquito flying at the Nats on the showline. It was really blustery but the model looked just fine in the blow. There are a lot of designs to choose from!

[Danny Fenton]

Hi Jonathan thanks for that, its not the models I have the problem with its the motor, ESC, and batteries, What cheap package could I get that would power a fun fighter sized model? ie 32" - 36" Or even say a 40" lightweight cub. It would need to be small and fairly slow to fly in the local park. Any thoughts?

[Fats Flyer]

Danny,
a 400 brushed motor with a 20 amp speed controller ,800AR 8 cell battery pack and micro servo's have served me very well for a 36 inch spitfire, me109, f-15, hawk and the likes.
This is a nice little set up that even Nigel Hawes recommends.
It's a cheap set up with alot of fun.

vince

[Patmac]

One of the cheap bell motor/esc combos from BRC or Robotbirds or one of the other retailers would be more powerful, lighter, & give better duration than a 400 brushed motor with the same battery. A battery pack of 7 or 8 2/3AF size Nimhs would be the cheapest option if you already have a charger but if not a 3 cell lipo & cheap Perkins charger would be comparable.

The lipo would be much lighter & give more power/duration flexibility.
suitable Nihms would be around 1400mAH, lipos 800 - 1800mAH. Avoid discount priced lipos.

Pat.

[Danny Fenton]

Thanks guys that sounds like excellent advice, any brands/suppliers that you would recomend? you say avoid discount priced lipos, how would I recognise one to be avoided?

[Patmac]

Here's some links to bell motor/esc combos

http://bounceurl.com/w8k8pmz

http://bounceurl.com/54t5yb1

http://bounceurl.com/iwye29w

http://bounceurl.com/b3t12j4

http://bounceurl.com/3r71jjp

They're all shortened URLs but should take you to the relevent pages.

Some people recommend only the most expensive lipo names as reliable. I've found that there are much cheaper alternatives especialy if you're prepared to shop internationaly. Ive bought a number of lipo packs from this site:
http://bounceurl.com/es40uq2
at half the UK cost & they've prove good quality. I only buy the 20-30C rated ones & normaly use them at a much lower discharge rate.

IMHO the ones to avoid are lipos that have previously sold at a higher price & are now discounted or are advertised on the same site as other brands with the same C rating & capacity but are substantially cheaper. I don't want to name a particular brand because it's my opinion but could be construed as libellous.

HTH

Pat.

PS it seems that from this site you will have to copy & paste the links I gave to get to the various sites.

[Danny Fenton]

Thanks Pat I will have a good rummage through your links tomorrow, thanks for that :)

[Fats Flyer]

contact overlander,they only deal with quality.

[Patmac]

Dream on Vincent.

Pat.

[Fats Flyer]

ive had no problems with them

[Patmac]

Apart from price & product quality neither have I.

Pat.

[Danny Fenton]

I didn't want to start a row guys, thanks for all the advice :)

[Patmac]

I think we could do with some smilies on this site.

Pat.

[Fats Flyer]

or grumpies

[Danny Fenton]

Thanks guys I have looked through the links and those prices are excellent. Sorry to be a pain but how do the numbers on the outrunners compare? 2205 must be less powerful than a 2208 or 2212. But what sort of power are we talking about in IC terms? I appreciate it depends on the size and number of cells.
There was a plan in RC Model World for a plane called the little Sue I was toying with building either it or something of a similar size. a scratch 36" wot 4 is another thought. The builder of Little Sue used an align 1000Kv BL450S drawing 9 amps. Can you make a cheap selection from the sites you have mentioned that would fly this, perhaps including a charger? I know I am being cheeky, sorry..... I am drawn to the 2208 with 15 ESC. Would the bell motor cut it?

[Alistair Taylor]

Time to dig out your G.C.S.E (O-level?) physics calculations....

The motor numbers relate to the size of the motors and "winds" - i.e. the number of turns or winds of wire around the motor armature.

Th winds dictates the KV - or how fast the motor would like to spin in response to a particular voltage.

e.g. KV of 1700 - apply one volt - motor spins at 1700 rpm with no load (and draws very little current)

As you apply load, the rpm goes down and the current/amps go up, depending on how much your load restricts your electric motor from reaching the rpm it wants to, in response to the voltage applied.

E.g. KV 1700 motor, running with 10 volts, wants to turn at 17,000 rpm. If the prop you put on it slows it down too much it will draw loads of amps and go up in smoke. The right prop will be the one that keeps the amperage within the limits of the particular motor.

Bigger motors can take more amps for a given KV (usually)

So choosing a motor is a function of;

- the prop you need
- the battery packs you want to use
- how long you want to fly for
- what kind of flying you want to do
- how many amps the motor can safely draw

If you're making a warbird - you want a power source that will give you a fair bit of revs - think small ABC screamer rather than four-stroke - coupled to a pitchy prop.

I've had really great results with a bog standard bell motor (1750 kv version), 15 amp controller, running on 7, 8 or even 9 cells, and an apcE 7x5 prop.

This setup flies the 30" nigel hawes tucano I built (top plane) with authority.

Battery packs I use; 500AR 7-cell (light), 800AR 8-cell (bulky, but extra weight helps with penetration on wnidy days), 1100 NiMH.

To fly slower - go to an 8x4 prop

To fly quicker - go to a 6x6 prop, and use 10 cells, or perhaps three lipos.

NB - Get a prop saver or you will break props on every flight, bend motor shafts, splinter bulkheads etc and generally not achieve good karma.

Or put some wheels on

Alistair

[Danny Fenton]

Thanks Alastair for taking the time to help, thats made things much clearer.
Cheers

[Danny Fenton]

Still struggling a bit LOL I have opted for a 125W CF2812 830KV Brushless motor, a 12-15A 'FLY' ESC. A Slo Fly 9 x 6 and a prop saver. I am looking at a 1500 3s1p pack. What do you reckon?
I am hoping this will cover a range of potential models.

I am struggling with a receiver and servos, I have a JRPCM9XII synthesised system, what sort of Rx can I use, ie only synthesised or can I use crystal Rx's, also if I bought GWS mini servos what connectors would they have? JR, Futaba, GWS?? etc...

[Alistair Taylor]

Sheesh I wrote a lengthy reply yesterday and then the system lost it for me.

OK - If your motor is a 2812 it's a 1500kv motor, not 830kv (the 2822 is an 830kv motor).

If it is the 1500kv version, I strongly suspect that the prop will overload it. A 7x5 would be better on 3s, an 8x4 on 2s (this is a guestimate - I don't use lipos)

It it's the 830kv version - you should be OK (although the plane may not fly as rapidly as you might like).

I haven't a scooby about the synthesised JR stuff. I fly fairly bog standard Sanwa gear.

Most servos down to mini size use the same type of connectors (although Futaba connectors have a raised edge that can foul non-futaba sockets/receivers). It's only very old sanwa gear, and the really tiny stuff that's different. For a 125W fun fighter setup you're probably best going for 9gram (e.g. Naro size) servos, as these should be able to cope with the aerodynamic forces on the control surfaces better than really small ones.

Hope this helps

AlistairT

[Danny Fenton]

Thanks Alistair, I know what you mean my thread yesterday took two attempts, the system was altered a bit yesterday I suspect that was the cause.
I originally was going for the 1500Kv but thought the revs would be too high so opted for the 830Kv and you are right I have just checked the order and it is the 2822 LOL
I am still not sure whether you can use a standard crystal Rx with a synthesised Tx, I may post a thread asking just that question. Thanks for your advice on the servos, I suppose at worst I can always solder my own leads on to whatever arrives.
Cheers

[Patmac]

It doesn't matter whether the Tx has a Xtl or is synthesised. You can use any make of 35MHz Rx except ones that are PCM. PCM Rx's need to be matched to their own manufacturer's Tx.
There's a mistake in the explanation by Kevin Crozier in the April RCM&E.

Pat.

[Danny Fenton]

Hi Pat, thats good news I can turn my Tx to PPM and use one of the tiny Rx's. Thanks for that :)