Author Topic: Which Servo (Read 13104 times)

haydenc · « **on:** May 15, 2009, 14:32:29 PM »

Hi All
Need help again.

I have always used JR radio gear and for no other reason that this is what I started with.
In these recessionary times I was going to try and keep my purchases in the country.
I notice that Island Models don't stock JR gear so I was thinking of using Hitec servos.

Question

Would HS55 servos be strong enough to use on Ailerons and Flaps on a 2.6M wingspan model.
I was going to use HS81s for the rudder,elevators and spoilers.
Would they be strong enough ?

Also
My Transmitter (JR2720) has a 1500mAh Ni MN pack. It only lasts about 3 hours and then needs to be recharged.
Is there a better power pack I could use on a 35 MHz transmitter.

I have set up mixes on the Tx. would this be why the battery only lasts for the short while?

Still loads to learn.

thanks again Fred for the forum.

I would be lost without it.

Cha

Fred · « **Reply #1 on:** May 15, 2009, 15:23:16 PM »

Hi Cha, thanks, but without questions, the forum is nothing too

hmm, I would put the HS55 to the spoiler, and HS81 everywhere else.
HS 81 has more speed and torque than the HS55, that's the main differences between the 2 of them.

But, HS55 are good servos, and can fit the bill on all the controls.

The only draw back, is that they are both plastic gears, and I tend to put metal gears everywhere now, as you can explode gears quiet easily on a bad landing, but unfortunately, prices are not the same when going all metal gears :cry:

For the battery, well, now for me, best move ever is to go Lipo !

Installed a 3S lipo on my MC18 last year... Only charged it once ! (And that was just a top up after 6 month, was down to 12.2 v instead of 12.7v!

) Now in May, and still haven't charged it yet...

I use a 3S 2500 mah, and charge the battery by the balance plug. You only need to check the battery from time to time, for me, only once every... well, I have to have a look some day !

Just turn on the radio to check the voltage, and that's it, but that never go down !
I left it turned on all day, fly, left on to setup gliders, and nope, still not down ! Drop around 0.1v a month and that's it, whatever I use it...

Totaly addicted to lipos in radios now ! Other than that, if your battery use to last longer before, might worth to do a few cycles of charge/discharge.
You can also increase the battery capacity (to 3000mah or something else..) as long as the battery pack still fit inside!

And no worries, mixings or not will not affect your battery life.

Oh, and for the JR servos, the problem we have, is that we need to order hundreds of them to have a deal with Graupner... And that's why we don't stock them as that will be more expensive for you to buy them from us than anywhere else outside Ireland (we try to keep our prices same as in the continent, but for that we have to discuss deals etc etc :!: ) but other shops in Ireland might have JR gears at decent prices.

Hope this help in your choice, but don't hesitate to ask if you have any question or need more clarification!

Fred

haydenc · « **Reply #2 on:** May 15, 2009, 18:31:07 PM »

Hi Fred.
Thanks for the quick reply.
Ill take your advice and go for the HS81s.
But I see they are out of stock so I have asked to be notified when they are avbl.
Lipos. Do they not explode when you try to charge them ??
I read something bad about them.
There is a Polyquest 2500 mAh 3C on the shop site but that is too big.
Tx battery compartment is 115 X30 X30mm.
I really know yery little about these things.
I just enjoy flying the gliders
So I need to be pointed in the right direction.

Cha

Happy Days · « **Reply #3 on:** May 15, 2009, 22:05:54 PM »

Hi Cha,

Regarding your Tx battery the cheapest option, if your present charger will operate from a 12v supply, is to take the charger to the flying area and recharge between flights from your car battery. (Assuming you intend to fly for more than 3 hours.)

As Fred said, Li-Po's are the best solution but they will cost a bit more. And they can only be charged with a charger that is suitable for charging Li-Po's. So if you haven't got such a charger you would have to get one.....adding to the overall cost. :cry:
Incidentaly Li-Po's normaly only catch fire when one of the following situations occur:-

a) the battery is physicaly damaged
b) the batteries terminals are short circuited
c) the battery is charged faster than the manufacturer recomends or charged with the wrong type of charger.

Other than that , for a given size, a Li-Po will hold more charge and weigh less than most other types of battery.

If your present battery is fairly new, I'd stick with it Cha. The battery in My Tx lasts about the same as yours. I make sure I turn it off between flights and I can normaly get a "days" flying out of it, or I recharge it from my car battery :wink:

Hope the above is of some help!

Keith

haydenc · « **Reply #4 on:** May 16, 2009, 11:37:15 AM »

Hi Keith
Yes the Li-Po option seems to be expensive but seems to be the ultimate solution.
A car charger would seem the cheapest solution all right.
My current (present - so there is no misunderstanding) charger is a mains 240v one.
As I would be charging a 12V TX battery from a 12V car system is it a simple connection of the 2 systems and the current flows from car to TX battery to equalise the voltage.
Or is there electronic gizzmos needed in the circuit.
Or is there a commercial car cigarette lighter driven charger system that I have not yet seen
More questions. more questions.
It keeps going on.
Thanks for the info so far Keith.

Cha

Happy Days · « **Reply #5 on:** May 16, 2009, 13:50:52 PM »

Unfortunately your Tx uses 9.6v (not 12v) and your Tx battery has to be charged in a certain way Cha so,....as you put it, there needs to be some electronic gizzmos. (Can't simply connect straight from your car battery

)

There are may "field chargers" (chargers that run on 12v input) on the market.

SMC have one just for charging 9.6v NiMH batteries for a 12v source for £5.99 plus shipping. ( www.sussex-model-centre.co.uk click on r/c equipment, click on chargers. First one on the list is ACE Quick Charger £5.99 )

I suggest this is likley to be your cheapest option Cha,.............IF you're sure you are gonna be flying for more than 3 hours at a time. :?:

That's a lot of flying! :clap:

K.

Happy Days · « **Reply #6 on:** May 16, 2009, 13:55:18 PM »

Sorry Cha, the first line of my previous post should have read

Your Tx battery runs at 9.6v (not 12V).....ect :oops:

haydenc · « **Reply #7 on:** May 16, 2009, 16:55:25 PM »

Hi Keith
Field chargers they are called.
Thanks for that.
So I am on the right road now.
Will have to get one of them.
Had a look at the Sussex Models site but the Ace Quick Charger is out of stock.
The CG 335 Pro seems to be able to charge TX and RX batteries at the same time ?
That looks a better option.

I know 3 hours is a lot of flying but I often set out on a spur of the moment, so the transmitter is not always fully charged.
So I start off from a weak position.

A FIELD CHARGER (now that I know about them) is what I need.
Though, it would be great to have a Lipo setup and, like Fred, not worry about discharged batteries.

. :oops:
Last Tuesday evening, spur of the moment, I flew my Stargazer. Started off with RX battery indicator showing down 2 dots on a 10 dot system.
No problem I thought as it is an 1100mAh battery.
50mins later the glider literally went mad. Developed a mind of its own. Piled into a heap of stones on the beach and cracked off its tail section.
Up till then I was a really happy chap.
I now know that I should check the battery condition under load.
Repairs now completed. waiting for wind to abate.

Thanks again for the help

Cha

Alan_Perse · « **Reply #8 on:** May 16, 2009, 18:12:40 PM »

You can buy a charger that will work with a 12V battery and off the 240V mains. I have one. I's made by Graupner and it's called the Ultramat 14. It will charge NiCd and NiMh cells as well as Li-Io and Li-Po cells. But you need to buy a balancer to charge the Li-Io and Li-Po cell (but I think the latest version has the balancer built in). There are also more advanced versions such as the Ultramat 16 and the Ultramat 17 but they are much more expensive.

Happy Days · « **Reply #9 on:** May 16, 2009, 18:48:21 PM »

You're very welcome Cha.

Sorry to hear about your little mishap last Tuesday

;

Tip: (If you don't already know it) When you use one of those 10 dot battery testers.........wiggle the control sticks to make the servos work while the tester is connected. The number of dots that light up will go down and you will get a better idea of what the actuall working voltage of the battery is.

Rule of thumb; If the number of dots that light up when the servos are working is half the total number, (or less)....DON'T FLY!

Unfortunately you've already found this out the hard way :wink:

Hope you're a Happy Chappie again now :lol:

Good luck Cha.

K.

haydenc · « **Reply #10 on:** May 16, 2009, 22:10:22 PM »

Thanks for the info Alan.
I had a look at the Ultramat 17 on Sussex site and it is expensive. about €100.
Not too sure what I will do now.
At least I have more info and hence more options.
It would be a very good charger if I ever got an electric powered glider.

Yes Keith, I did learn the hard way.
When I arrived at the wreckage last Tuesday the indicator was in the last 3rd of its range, but when I moved the control sticks on the tx it flashed into the red zone and down to the last dot.

a terrible way to learn, but I will remember.

Cha

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Author Topic: Which Servo (Read 13104 times)