MJD

My Feedback: (1)

Literally..

I just powered up the flight pack on my Blink for the first time in 3-4 years. 2 x HS-55, one HS-50 on throttle. This time I used a Spektrum parkie receiver and 2s LiFe battery. I suspect the voltage may be at play here but need to be convinced.

Two HS-55's on elevons, both jumped into life, both moved when stick wiggled, then one of them melted a 1/4" dia spot on the bottom, side of the case just inboard of the servo lead entry point. The other is fine. The cooking servo actually still worked up to the point I yanked power, and rechecking it again quickly it still did (though not sounding right). The HS-50 and other HS-55 continue to work properly.

Beats me why, any thoughts? They were fine when I parked it.

If it's voltage, I can use a diode to drop voltage to just below 6v.

In my humble opinion, 6.0 - 7.4V should be the new voltage standard for all standard receivers and servos. I guess things are heading that way.

longdan

What about those that use glow engines?

hllywdb

Don't get me started on HS-55's, or the feather recievers for that matter. I have had better luck with the cheapest Chineese servos than the HS-55's. That being said (And YES, it makes me feel better) in your case I think the HS-55's were designed when all we had were 4.8v clunky packs that were heavy enough to balance a tail heavy Cub.

Andrew

At full charge, a 2s LiFe pack may reach 7.2v. The HS-55 is rated for 6v, but yours may have had other problems, particularly if the other is OK. Did you notice if the other case was hot?

http://www.servocity.com/html/hs-55_sub-micro.html

ffkiwi

What's wrong with the feather Rx's? I've got a couple that I haven't got around to using yet-but of course they're on NZ bands not the 72MHz.......make that band singular-just checked and both are for the 36MHz band.

ChrisM
'ffkiwi'

hllywdb

I have 5 feather recievers. 3 went back to the factory and got replaced. Kudos to Hitec's customer service. But they work for a while, then fail. I have replaced them on all the planes I LIKE with Bergs and have had zero failures. I use the feathers and the last of my HS 55's on my combat planes, which tend to have a short lifespan anyway.

ffkiwi

Fail as in stop working completely without warning?, fail as in start glitching?, fail as in start working erratically?, fail as in seriously diminished range?, fail as in continuously jittery servos?? Since I have a couple it would be useful to know what to keep an eye out for............
.......and if HS55s are getting such a bad rap-dare I ask about HS45's......?

ChrisM
'ffkiwi'

BMatthews

I only bought one Feather. It glitched and skipped so badly with other radios operating at the same time that it was the last one I bought.

It even glitched, but not as much, when I was the only guy at the field. That was enough. I tossed it into the trash... literally.

hllywdb

Hey Chris,
1 quit in flight, the next 2 suddenly had about 20' range, those were replaced, the next one started glitching as soon as it was turned on one day, then the last one would work, then have 30' range, then work, then glitch. I have 2 that still work, in combat planes that I fly close.

ffkiwi

thanks for that info-I'll keep a very close eye on them once I start using them-IF I start using them.....! Not short of Rx's in any case. Haven't heard of any issues from my own club (Wellington MAC) regarding them, but then I haven't been listening to the chatter either!

ChrisM
'ffkiwi'

longdan

HS-55s have been around for a long time. I have half a dozen that I've had for about 12 years and they work fine. Back in the day, they were considered to be pretty good, and recommended by manufacturers in many kits.

Perhaps in that time, Hitec have economised or outsourced their manufacturing.


I think what you would need would be a 5v voltage regulator. It looks a bit like a transistor with 3 pins. One goes to +ve battery, one to -ve, and the third produces a steady 5 volts.

Boomerang1

This is what I'm using, check out post 21.

http://www.rcuniverse.com/forum/m_11..._1/key_/tm.htm

Or, I'm sure Hobby King has something ready to use for less than the price of buying the parts!

http://www.hobbyking.com/hobbyking/s...ator-UBEC.html

John.

exocet-RCU

My Feedback: (1)

I have three of these: HKU5 5V/5A UBEC. they are super light and I haven't had any problems with them. They allow me to run a 2S360 lipo in my Pageboy (5 ounces, .010 powered) and my Zero (9 ounces, .049 powered). At around $5, pretty hard to beat.

MJD

My Feedback: (1)

I'm talking about people using glow engines. What I mean is that with the widespread availability of small, affordable 2S LiPO and LiFe packs, that weigh much less than their capacity-equivalents in NiCad or NiMH, they just make so much more sense as Rx batteries.

MJD

My Feedback: (1)

It did not feel hot, and it works fine still. I guess the other servo had some kind of issue, though I am left wondering if it was damage or just something waiting to explode, and if it was voltage related.

Actually - I have never charged the battery, I pulled it out of the package maybe two weeks ago, so it still has the holding charge as shipped. I just plugged it in to check out the flight pack. So I would doubt it is at peak voltage.

I'll play it safe and watch the voltage to the servos. 6.6V nominal had me nervous enough, but the peak is a bit out there for HS-55's I believe.

MJD

My Feedback: (1)

I see they are available in the US warehouse too - cool. I have a couple of Novak 3A regulators at 8g each, but they were a bit more than $5..

Even at 8g = ~1/4oz, I feel reluctance to install them if not needed.. however the potential consequences of not using one if it is needed is another matter.

Mr Cox

I think the weight savings with Lipo and LiFe are rather small when you include the much needed BEC in the calculation.

flycatch

My Feedback: (26)

Nothing more than a internal short. The PC board within the servo case shorted to the metal casing of the motor. Things happen beyond our control and your case on the bench and not in the air.

MJD

My Feedback: (1)

Makes sense. The fact that the servo still responded to the stick, though a bit slowly, suggests something like this versus a critical IC or other component going up in smoke. Could be I manhandled the casing too much and shifted internals.

I don't use HS-55's any more on 1/2A's, I switched over to HS65HB's. I stripped one HS-55 just bumping the rudder on a GWS foamie Tiger Moth while handling it to change batteries.

exocet-RCU

My Feedback: (1)

I just weighed the BEC and 2S360 combo I mentioned in post #13. The weight is 1.2 oz with all connectors. To date I haven't found a 4.8V NiCD or NiMH battery that weighs that little. Not saying they aren't out there, just that this combo is still VERY light and the bonus is that I have never needed to charge my battery at the field.

Tim

Oh, and the total cost is less than 12 dollars

Mr Cox

A 400mAh NiMh battery weights 34g (1.2 oz) with connector. So there is no difference to talk about really in terms of weight.

MJD

My Feedback: (1)

I feel more comfortable with LiPo's than I do with small NiMH packs, only because I've had some surprises.

If the regulator/BEC was not needed the scale would tip in favour of newer battery technology. I hope 6.0-7.4V nominal becomes the standard in the future, rather than 4.8 - 6.0V.

Andrew

Realistically, your first thought of using a diode may be the most feasible. Getting the voltage close to 6v may be all that's necessary - I would be inclined to probably use a 50 PIV 3A or maybe even a 6A selection. With only two servos running, the 3A probably would carry the load and would be small and light (and cheap).

MJD

My Feedback: (1)

That's probably the KISS solution. I have a pair of Align "regulators", which as I found out after they arrived are not regulators but essentially a servo extension with a pair of dropping diodes in parallel/reverse. I can save some weight by clipping out the unneeded diode and use the rest.

Now to decide if I should tempt fate and change out the HS-55, or go to "better" servos. I'll flip a coin.. I can live with the HS-50 crapping out on throttle.

airraptor

My Feedback: (66)

Servos are rated by all as either 3.7, 4.8, 6.0 or 7.4 volts.

The 4.8 and 6.0 was the standard till 5 years ago or so. at that time the common batteries were 4 and 5 cell nicad or NiMh packs. so for advertising the MFG stated all servos as 4.8- 6.0 volts as that is what the battery MFG showed on packaging.

MOST all 6.0 servos will handle a LiFe battery. I have found that some of the JR, Hitec, and Airtronic ones have burned up everynow and then. I would say one out of every 25-30 with the Life Packs. to me this just shows a bad servo from the beginning..


I only use LiFe Packs. I will never go back to Nicad or NiMh. no point. yeah you may say a NiMh pack is the same weight but it isnt. the guys runnign regulators are just a little scared to run with out them. We humans dont like change..

MJD the HS-65HB (karbonite gears) are very good servos. I buy them in bulk. i think they are the best 1/2A servo. now you can get other lighter ones that work great also.

so run the LiFe's they are the future...

If you are still running NiCads way behind in tech but who cares fly how you want. LiFe's are such a better battery.