The Atom Special

[Richard Harris]

Caveman,

This is my mistake and something that I missed in the write up, there should be a 14mm gap as MAX suggests.

Sorry for any confusion.

Rich

[Vecchio Austriaco]

congratulations. 1000 replies on your atom thread

VA

[Caveman]

No problem Rich, thanks for your prompt reply.

I'll chop 10mm off the root and re-balance the blades.

Cheers GDB

[Deyrick Gibbins]

Drilling a new hole would be a lot easier and no need to rebalance.

For Steve Jones did you try a larger diameter prop on that motor, 980Kv is a bit low for a ten inch prop on a 250W motor.

I use a 970KV in my Funcub and that runs on a 12X6, that being 350W though, even the 1100KV I used in it ran an 11X5.5

[Max Z]

Posted by Deyrick Gibbins on 05/01/2015 14:54:15:

For Steve Jones did you try a larger diameter prop on that motor, 980Kv is a bit low for a ten inch prop on a 250W motor.

The Watt rating of an electric motor is only a measure for what it can handle, the Kv value and the chosen prop should match the plane, not the motor power rating! A 10" prop is more than adequate for the Atom.

I agree that 980Kv for a 10"x5" is a bit on the low side, a larger prop could be beneficial. But don't overdo it.

(as I posted earlier, I am running a 10x5 on a 1020 Kv which delivers around 150 W)

Max.

[BILL PETTIT]

I like my nose! It's a juce bottle that had an interesting neck.

And the HK head mounted.

I also set my motor on 1/2" standoffs so I could drill a hole behind the motor to route power leads.

Bill

Edited By BILL PETTIT on 05/01/2015 18:46:10

[Ian Jones]

I'll be starting mine soon, is there a list anywhere of post RCM&E article "official", that is recommended by Richard, modifications.

No doubt I will make one or two changes of my own but I'd like to have the latest info to base it on.

Thanks, Ian

[Steve Jones 2]

My first Red Atom runs the Rich suggested SK3 980kv motor, the second Yellow Atom runs an SK3 1240kv motor.

Both run 30amp esc and APC 10x4.7sf props. Batteries used are Zippy compact 3s 1800s or 2200s

Steve

[Stephen Jones]

Hi Deyrick and Max Z,

I do not have a Prop Larger than a 10x5 at present i could buy a 10x7 and try that but i fear it is more to do with the fact my batteries have lost the urge .

I took two of my fast models to fly at are club field just before Christmas , i sat one down on its dolly and tried to take off . It would normally shoot off like a scalded cat down the field but i struggled along . So i tried again with a different battery thinking maybe i did not charge that , but yet again it struggled and i broke a prop in the process .

I put it down to the fact that the grass was a bit longer and wet .

So i moved on to the next but this time went for a hand launch and that did not have the usual urgency about it .

This weekend i recharged all my batteries and tried a power test on them . i got very poor performance from them .

So now i need to buy new batteries and a transmitter at a time when my funds are low .

Steve

[BILL PETTIT]

Stephen:

It sounds like you have been around the patch for a while now, but I'm going to ask anyway. Do you have a charger that balance charges each cell as it charges. I'm not the sharpest knife in the draw and that seemed to be the problem with some of my batteries and it took someone to say something to me about it....

Bill

[Stephen Jones]

Hi Bill

i have two similar too these .

Steve

[Ian Jones]

Posted by Steve Jones 2 on 05/01/2015 18:49:33:

My first Red Atom runs the Rich suggested SK3 980kv motor, the second Yellow Atom runs an SK3 1240kv motor.

Both run 30amp esc and APC 10x4.7sf props. Batteries used are Zippy compact 3s 1800s or 2200s

Steve

Thanks Steve,

As much as anything I was thinking about the head setup, shims, firbreglass plate shapes and any weak spots (such as in the booms perhaps?). Anything tthat time has revealed that would make Richard change the original plan.

Ian

Edited By Ian Jones on 05/01/2015 20:26:45

[Baz Lewis]

Bill

If you are getting a B6 charger.....this one is cheap as it has the adapter built in...these retail at over £20 at the cheapest.....**LINK**

The adapters on their own are around £8 but mostly from China....I get 5 adapters at a time for club members as you get the odd one only lasting 12 months....I find the leads go first and not always the adapter block.....

Buy it now's are these......http://pages.ebay.com/link/?nav=item.view&id=281205132403

Edited By Baz Lewis on 05/01/2015 20:34:54

[Phil Winks]

Posted by Baz Lewis on 05/01/2015 20:32:05:

Bill

If you are getting a B6 charger.....this one is cheap as it has the adapter built in...these retail at over £20 at the cheapest.....**LINK**

The adapters on their own are around £8 but mostly from China....I get 5 adapters at a time for club members as you get the odd one only lasting 12 months....I find the leads go first and not always the adapter block.....

Buy it now's are these......**LINK**

Edited By Baz Lewis on 05/01/2015 20:34:54

Personally I'd go for something with a little more output power than a B6 try this at 10A 200W charge rate it is more capable for many of the modern 5C charge rate batteries and still won't break the bank, for instance a 3300 gens ace can be charged at 16.5A max charging at 10A won't get it even close to the danger point and will charge at twice the speed of the B6,

I've had mine about 5 yrs now and has worked faultlessly ok its a 12 to 18v input which at the field is you car battery or more likely a leisure battery in the shed I use a variable output bench psu which also doubles as power supply for my mini drill, hot glue gun and micro lathe that all use between 6 and 18 volts

[BILL PETTIT]

Thanks for the help fellows but I think you misunderstood. Was asking Shephen if he was balance charging his batteries. I have a nice charger and it works fine. But thanks for your suggestions.

Bill

[Richard Harris]

VA,

Never even noticed! good constructive replies as well so well done chaps

Bill,

I like your nose too!

Ian,

The cheek of it! the Atom is bomb proof . I have crashed mine really hard and have not really broke anything as such. A few pieces off the blades and a few joints dislodged due to the battery wanting to carry on moving forwards as they do. Of course it was not the model, pilot or set up that caused the crash but the Spektrum radio

Stephen,

I guess you could try an IC prop if you have one? but I am sure you are correct after your models are showing poor performance from a battery that once worked fine.

Rich

[Stephen Jones]

Hi Richard ,

I did not think you could use ic Props on Electric motors due to them being heavier and stalling out the motor on start up .

Being a bit of a speed freak i have some ic props 10x6 , 10x7 , 10x8 , 10x9 ,

Steve

[Richard Harris]

Stephen,

You can use ic props on electric motors but you can't use electric props on ic, it has to be worth a try? I'm using an 11 x 5.5" prop on my new set up, it is over powered but fun

Always worth checking the balance of your cells as Bill suggests if you don't already do this.

Rich

[Stephen Jones]

Hi Richard ,

I always check my batteries are balanced ,

I find it very important to get the correct CoG

Steve

[Ian Jones]

Posted by Richard Harris on 05/01/2015 22:55:05:

VA,

Never even noticed! good constructive replies as well so well done chaps

Bill,

I like your nose too!

Ian,

The cheek of it! the Atom is bomb proof . I have crashed mine really hard and have not really broke anything as such. A few pieces off the blades and a few joints dislodged due to the battery wanting to carry on moving forwards as they do. Of course it was not the model, pilot or set up that caused the crash but the Spektrum radio

Stephen,

I guess you could try an IC prop if you have one? but I am sure you are correct after your models are showing poor performance from a battery that once worked fine.

Rich

That's good to know Richard, I don't use Spektrum . So these shims then, are they required or not? If so are they best attached to the root of the blades, tacked to the fibre glass plate or is it best to reshape the blade roots?

Ian

[Steve Jones 2]

Both my Atoms run 0.8mm shims, 4mm wide, fitted to the blade root reinforcement plates before the blades were covered with film

[Deyrick Gibbins]

I would increase the diameter rather than pitch Steve, an 11" would be better for 980Kv.

Think of it like gears Lower Kv swing bigger props, turning a small prop is reducing its efficiency as well, running same 3 cell battery on say 1200Kv would need a smaller prop or you would pull to many Amps and the battery voltage would sag.

On your batteries, have you left them fully charged for long periods ie longer than a couple of weeks, this is known to reduce the capacity as well.

If I have packs charged and ready for the next day and the weather changes, I discharge to storage capacity (3.75 to 3.8 per cell), this is good practice and helps life from what I have read.

I had a couple of packs die on me similar to yours when I left them for long periods ie a month or more when I first started.

I have 3 balance chargers so really only have batteries in a full charge state if un used for flying from one day to the next.

Edited By Deyrick Gibbins on 06/01/2015 15:29:31

Edited By Deyrick Gibbins on 06/01/2015 15:34:17

[Levanter]

Just about to start my first autogiro, the mass build Atom of course! Is it helpful to keep weight down as much as possible or does it not matter so much on a gyro?

[Baz Lewis]

With reference to the blade shims......I decided to spot glue a profile of 1mm hard balsa to each blade mount...I then sanded the cross section to a taper until it feathers at the edge. Soak cyno into it and lightly sand when dry....alternative method!

[Mike Stevens]

Completed canopy at last.