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New Hitec Wing Servos


satinet

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Hello,

I noticed on rcgroups the other day that hitec is bringing two new wing servos out.

What is interesting to me is that this one is 8mm thick (titanium gears)! Also the fact that it is a HV servo (so can run on a 2s life/lipo).

http://shop.lindinge...oducts_id=96032

http://www.hitecrcd..../hs-7115th.html

They are also doing a 10mm hv servo with normal metal gears, at a lower cost:

http://shop.lindinge...oducts_id=96032

(any 5125 dna in there??)

Kind of expensive for hitec but 8mm would make some installs a lot easier.

Wonder what the price will be in the uk....

T

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I do like high voltage servos but will wait until I have seen some used for 6 months or more.

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yeah you don't always want to be the first to jump.

I would think the HV servos would be come the norm in the coming years. Although saying that most servo manufacturers still haven't worked out you don't need a long servo lead on a wing servo and that decent horns are quite important (hello mks...). I assume with hitec it will have full rotation not like mks either.

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do you not still suffer from higher current drain from the higher voltage .........you dont usually see people putting 2500mah lipo or life cells in do you

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For me they use a big more current but nothing dramatic. I only use 1100MAh Life batteries and after a days F3J flying which normally amounts to about 1 1/2 hours use they take 500ma when I recharge. Previously with non HV servos the recharge would be 400ma. You may well use more flying other types of model though.

My packs are quiet small but you can find small 1600 or 2100 ones easily on the net.

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thermaldoctor

Austin - Can I pick your brain please. What do you consider the benefits of using Life batteries over normal Nimh in F3x planes?

I know the higher voltage can be used on HV servos but a standard set up with 4 cell nimh gives enough speed and torque I would think. So I'm struggling to see the advantages for gliders. I can understand using them in power planes where it's handy to have a lot of capacity and current ability for not a lot of weight, but gliders are always tail heavy without any nose weight so a relatively heavy battery up front is not a bad thing.

Just curious

Neil

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Austin - Can I pick your brain please. What do you consider the benefits of using Life batteries over normal Nimh in F3x planes?

I know the higher voltage can be used on HV servos but a standard set up with 4 cell nimh gives enough speed and torque I would think. So I'm struggling to see the advantages for gliders. I can understand using them in power planes where it's handy to have a lot of capacity and current ability for not a lot of weight, but gliders are always tail heavy without any nose weight so a relatively heavy battery up front is not a bad thing.

Just curious

Neil

Hi Neil,

You are correct in saying that 4 cell Nimh gives enough speed and torque but improvements on those things cannot be a bad thing.

However there are a few benefits from using Life over Nimh. If you do use HV servos the power, holding power and speed are much higher.

Life batteries hardly self discharge and are better at this than even eneloops. They deliver their actual rated voltage for nearly their whole capacity. They can be charged faster than Nimh and they can deliver higher currents without voltage drop than Nimh,

Life cells weigh a lot less than Nimh, for example 4 cell 1600 intellect Nimh weighs about 105 grams and Life 1600 is 70g

In addition the Life cells can be charged/discharged up to 1000 times where as Nimh are around 300 cycles.

For the additional cost I feel its worth it.

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isoaritfirst

I have been using Sanwa HV in my AlliaJ - which has had lots and lots of air time running from LiFe so not pushing the servo V limits running at a nominal 6.6V

Its not a decision I came too based on speed and torque - but I am very happy to take that benefit.

It came down to better batteries. Eneloops are at the limit of their discharge capability and on some of my models this was evident when watching an onboard V checker and jiggling everything. Although on other model this was less evident - so I do still use eneloops occasionally, only ever as 4 cells packs. But also use intellect 2/3 A where I consider the eneloops may struggle. This is also more of a problem flying slope in sub zero temperatures and running high power digital servos. As servo performance improves so will the battery stresses (I imagine). HS85 no problems MKS etc possibly - starting to push the limits.

My decisions were based more around the LiFe cells having only two cells - I have spouted off before about reducing cell count for better reliability. They also have balance tabs so although at two cells, they haven't reached my ideal the balance tab allows constant management and assurances that the cells are still happily matched.

With comp models especially, I often charge up and ready 2 or possibly 3 models for the weekend, then only fly one. This may go on for 6 months plus. It destroys NiNh, usually by the cells going out of balance. I know good management can improve on this but LiFe remove that worry, and out of balance cells let you down often with no warnings.

Battery usage from the Alliaj is what I consider normal - rarely going over 750mah after a very full days sports flying.

My FS4 also has the same set up but uses a much more power hungry arrangement on the wing linkages, It seems to use around twice as much power as the AlliaJ.

Both run on Hyperion 2150 Life cells and 6 x Sanwa HV 12.5mm servos, bit of a squeeze in the FS4 but I also like physically big servos.

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isoaritfirst

I recently changed my FS3 to LiFe cells as well. This model has top end Graupner servos in the fuz and 3150's in the wing.

Neither are rated for 6V. and at

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That being said mike the hyperion batteries are actually only "5c" from memory. So the 1450 only has a max dischage of about 7am/hr which is actually less than a 2/3a Nimh. 2/3a packs have the benefit of being more shapeable in terms of cell configuration e.g |||-

When I was flying my crossfire 2 in winter the Life was reading 6.2v at times, on the onboard telemetry on my aurora.

What I like about life is the discharge curve compared to 2/3a batteries and the fact that you get longer flight times due to the flatter discharge curve.

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This is of real interest to me at themoment as I have 4 MKS servos in the wing of a plane with linkages compromised by horn and arm length. As result I get a fair bit of noise when the servos are moving and at extremes of surface throw. I am working on the linkages to remove this as much as possbie but have opted for a telemetry Rx to keep an eye on things.

Now then… if I go for an LiFe cell how much warning will I get of a battery running out of steam if the voltage stays so constant for it's discharge cycle?

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This is of real interest to me at themoment as I have 4 MKS servos in the wing of a plane with linkages compromised by horn and arm length. As result I get a fair bit of noise when the servos are moving and at extremes of surface throw. I am working on the linkages to remove this as much as possbie but have opted for a telemetry Rx to keep an eye on things.

Now then… if I go for an LiFe cell how much warning will I get of a battery running out of steam if the voltage stays so constant for it's discharge cycle?

This flat discharge curve is the reason why I have shied away from LiFe so far. I use LiPo + regulators exclusively on all my models (even the Pace and the Speedo with their tiny fuz's). I get enough warning of when to charge with their more "rounded" discharge curves.

The main advantages over NiMh?: MINIMAL SELF-DISCHARGE.

I don't buy that "one more thing to go wrong" with a regulator argument. There is a whole pile of electronics already in our radio transmitters and receivers that we have to rely on to not go belly-up and cause a crash. So, I'm kinda used to putting faith in electronic components....

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This is of real interest to me at themoment as I have 4 MKS servos in the wing of a plane with linkages compromised by horn and arm length. As result I get a fair bit of noise when the servos are moving and at extremes of surface throw. I am working on the linkages to remove this as much as possbie but have opted for a telemetry Rx to keep an eye on things.

Now then… if I go for an LiFe cell how much warning will I get of a battery running out of steam if the voltage stays so constant for it's discharge cycle?

The voltage does drop under load.

To be honest I have close to zero faith in voltage checkers even on nickel batteries. The other night I left a battery connected to a receiver and it went totally flat. I charged it for about 10 minutes and pressed the check button - oh battery full.... :eek:

As it shows on your TX battery level indication it will stay at the same voltage for ages. Now if you have been flying for 4 hours your battery isn't as well charged as it was. You know if you fly for ages with the model and use a checker on the battery the voltage stays pretty much the same.

If the low voltage warning keeps going off more than normal you might find that useful. But unless you set the alarm really low it just goes off all the time, when you bang the sticks. E.g on the hitec system you set the battery alarm at say 4.7v on a 4 cells nimh you will think you are going to crash every 5 minutes. I had it set at something like 6.1v on the Life pack.

In my experience Life are effected by cold equally as badly as nickel types. I like them though, especially on less flown models where you can just pick it up for a play whenever you want. It's less relevant to me on models that I fly a lot because I don't leave the battery uncharged for long periods of time. No it is not easy to tell how discharged they are but I don't think it is on other types either (perhaps less badly). Both lipo and life should give you longer flight times as they can keep giving for a larger part of their discharge curve AFAIK.

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isoaritfirst

Not sure what thedischarge rate of the life cells is but certainly intellect cells at 30c are very good.2150 at 5c will be enough though and a lot better than eneloop in cold weather.

As I said I use life,2/3a, and eneloop. keep eneloop for simple models were servo sizes number and performance needs allow them to be used without pushing them to hard. I use 2/3a where I need the power and don't have hv Servos. New installs I use life.

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thermaldoctor

All intersting and valid points thanks ;)

I now understand life advantages a bit better other than the obvious one of more voltage. For me, I don't think I'll be going down that route just yet in gliders. As for my new power planes? Yes. I can see the benefits and will fit them out with life and HV servos in order to take advantage.

Anyway, going back to the original topic, those new Hi-tec servos do look interesting. As Austin says, give it a while before jumping ship and see what people say. Wish I'd done that with a certain 3 letter brand (four to me). I like the fact Hitec are not quoting crazy torque figures to promote sales... :popcorn:

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I haven't actually had any problem with eneloops or vapex instants. Done a fair bit of winching with my tragi which will draw more current than sloping.

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thermaldoctor

Interesting thanks. A winch launch is going to stall all 4 wing servos for the majority of the tow so good to hear normal AA eneloop type cells working well. It shows 2/3 Intellect types and life are more than okay. I think it was the very high capacity standard nimh AA's that suffered most - they were meant for low drain digital cameras etc

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  • 1 month later...

Over on RCG they are finding the thin HS-7115 servo a good fit for the D60 elevator, interestingly its so thin that when you remove the label / sticker it reveals the motor inside the servo

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