Extra cooling of motor

[solentlife]

As some know - I was given an F16 70mm model in awful state and I rebuilt it ... I fitted the recc'd 2800kv bullet motor ... but thrust on the 4S is poor.
I read a lot about the motor and various advise that 5S will burn it out due to the rear cone not having sufficient cooling air exits.

My question is ....... what about cooling fins ? Can the motor have fins added to aid 'sinking' the heat away ? Are such fins available ?

Here's the motor in question .........

[img]

[/img]

http://www.hobbyking.com/hobbycity/s..._for_70mm.html

Nigel

[TopSpin]

Nigel, I have never seen a heatsink for an outrunner most likely due to the imbalance it would create. I have several large inrunners that use heatsinks but that's a different matter.

What you need is more soup at 14 volts and this may just be the answer for you.

https://www.leaderhobby.com/product....=9394001220638

This motor will provide much more power on 4S and stay cooler in the process. I realize that a higher KV motor running cooler is counter intuitive but trust me this motor will run much cooler on 4S and still give you the fan speed you want.

John.

[JetPlaneFlyer]

Yeah, I've only ever seen add-on cooling fins for in-runners.

What about simply cutting off the rear end of the cone to provide a larger exit hole for the air?

[solentlife]

Originally Posted by JetPlaneFlyer

Yeah, I've only ever seen add-on cooling fins for in-runners.

What about simply cutting off the rear end of the cone to provide a larger exit hole for the air?

After posting - I realised it wouldn't work because of the spinning outer body !

The cutting of the cone is a question I posed ages ago - but no-one answered. I've read that some have drilled extra holes in the cone.

The EDF unit is sealed into the fuselage and will need to be cut away to get at it. I would like to actually remove the cone and have the motor plain ended .. that way it must be better for cooling.

I find it hard to believe that anyone would design a poorly cooled motor as this ... I should have gone for a different design ...
I have a 3700kv heli motor I know I can fit in there if necessary. But first I would like to try the 5S on the installed motor ....... I know the thrust is good then - but no idea if the motor will burn out ... initial static test for some seconds didn't create any smell or noticed heat.

Nigel

[solentlife]

Originally Posted by TopSpin

Nigel, I have never seen a heatsink for an outrunner most likely due to the imbalance it would create. I have several large inrunners that use heatsinks but that's a different matter.

What you need is more soup at 14 volts and this may just be the answer for you.

https://www.leaderhobby.com/product....=9394001220638

This motor will provide much more power on 4S and stay cooler in the process. I realize that a higher KV motor running cooler is counter intuitive but trust me this motor will run much cooler on 4S and still give you the fan speed you want.

John.

I believe you ...... but I want to up to 5S if possible ... this F16 is big !! Guy who gave it me ... when he flew it - on the factory supplied gear (mine is replacement gear) .. it struggled to fly. I read up on the factory site and it quoted 5S ... the shop had supplied with 4S.

Nigel

[JetPlaneFlyer]

5s will be a huge leap in power. Something approaching twice the power. Amps will be up to something like 150% of the 4s figure. Make sure the ESC can take it.

[TopSpin]

I'm willing to be that with the higer KV, and higher peak current motor that you won't need to go to 5S.

[solentlife]

Originally Posted by JetPlaneFlyer

5s will be a huge leap in power. Something approaching twice the power. Amps will be up to something like 150% of the 4s figure. Make sure the ESC can take it.

When he gave it to me .... (I'd been at him for ages to let me get at it and sort her out !! ) I knew she was grossly underpowered. Not only that but it had retracts, vectored thrust etc. He ripped that lot out to fit to his Multiplex ...... that went same same fate as well ! But I haven't been given that one YET !

I intended from start to put 5S into it ... it's just that he gave me the 4S packs he had for it. The Nanotech lived up to it's crap reviews ... was no better than a 3S !! The standard 4S he gave was too low on C rating to ever be good enough.

I tested her with 4S kigher rated I had ... and it was very poor ... great when NOT installed ... but as soon as installed - it near halved the thrust. The duct is fair and exit is tapered down to optimum. It's just total crap !

I should have looked harder at motors for it ... but I bought the recc'd motor ... silly me ! I read that some had overheating on 5S and drilled extra vent holes. I put it down to usual cautious modellers ... which I am guilty of not being when it comes to pushing limits of Lipo's motors etc.

ESC is well able to cater for 5S ... if I remember rightly it's a 60A with separate BEC. The LiPo I have for the model now is a 5S 3000 ... when tested she went of my scale !! I borrowed wife's kitchen scales and registered over 2.4kg total ... deducting 1.3kg for model weight ... gives me a thrust result of 1.1kg. A much better result. In the air I'm hoping for better. But the big fear is the heat and motor giving out.

The model was so badly damaged when handed to me - I had no choice but to glue the EDF unit in and hatch. There were no mounting or hard points remaining. The fuselage had to be rebuilt in places. So now to get at this piece of crap means to cut her open. Something I'm not too happy about. If I do cut her open - then it will be to install a higher KV motor ... namely my 3700 heli motor that will turn happily on a 4S ... amps draw though will be HIGH ! Maybe need to swap out the ESC to much higher. I do have a 70A ... but that's on my Parkjet for speed trials ... (expecting final speeds of over 275kph ... possibly 300 there).

The model is a fine looking machine and I would like to have a new one .. but only if I can install better power ... the stock as I see it is barely enough. Here she is via a UK dealer ...

http://www.rcwarbirds.co.uk/edf-jets...rame-only.html

And here's a demo video from the chinese site ... but wey-hey ... that's Banana Hobby guy ?

http://v.youku.com/v_show/id_XMjkzNzc0MTA4.html

I've now found the spare parts listing !!

Nigel

I still wonder at the logic of designing a motor that has insufficient cooling air exit.