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Power hd 1440a servos

Gliderguy

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Noticed the Power HD 1440a servos look a lot like Turnigy 1440a servos. Thinking about these for my new Chrysalis Lite. Any thoughts on how well these would hold center?
 

Konrad

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Turnigy might be contracting with Power HD to be their OEM. Turnigy basically just rebrands products. I like to find the OEM as they often (not always) use better components than the rebranded product. This is often called building to a price point.

I've had very good service from all my Power HD servos.

Now I don't think the 1440a is suitable for the Chrysalis Lite. This is because of the low torque and the high demands from the high start launch.
https://alofthobbies.com/power-hd-1440a-micro-servo-08-kg-1110-ozin-09sec.html

I'm using the D47 servo in my Chrysalis Lite F3-RES because I can run them at 7.4 volts and I have over a dozen of them needing a home!
https://www.dymondusa.com/Servo-11305-D47-Power-Servo.html

If buying servos today, I think a much better servo would be these.
https://alofthobbies.com/ks-hd-47mg-servo-1-2kg-16-6-oz-in-10-sec-5-6-grams.html

For your reading enjoyment You might want to follow my Chrysalis Lite F3-RES thread here.
I will say that with the short nose of the Chrysalis Lite F3-RES I'm have problems getting the CofG far enough forward to balance on the CofG shown on the plans. This really isn't too much of a problem as the CofG is moved aft after the maiden flight.
http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=22619.0

All the best,
Konrad
 
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Gliderguy

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Thanks,
The KS HD 47mg servos do look pretty good. Haven't been much into digitals but maybe I'll try some. I've used D47s in the past and they're mostly OK but kind of expensive for me just now in my present economic format.
Thanks for the build log. I looked it over. Every little bit helps, at least I know a bunch of stuff not to do ;).

Dale
 

Konrad

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Thanks for the build log. I looked it over. Every little bit helps, at least I know a bunch of stuff not to do ;).

Dale
That is why I go through all the trouble of posting build threads. That is so others can learn from my mistakes! Not only you but hopefuly the OEM!:rolleyes:

I really like what Don Stackhouse says as to how to film cover thin trailing edges. Again I think that information should be in the Chrysalis Lite F3-RES manual.

As to value I agree, the HD 47MG is not twice as good comparied to the 1440a as the price might indicate. But it is far more suitable for the aplication. I'd hate to see one loose a $300 F3-RES glider as a result of saving $10.

The 1440a will work for a dozen or so flights (maybe 100). But the load on them durring launch will burn out the motor brushes given enough launches.

I use the 1440a for my light 100 gram rubber band Free Flight to RC conversions, such as the Guillow and Dumas kits.

All the best,
Konrad
 
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Gliderguy

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I strained a little bit and decided to go with Dymond D47s (except for the spoiler).
I want to do the best job on this plane that I can but I do hate it when my watchmaking instincts kick in and I start getting too fussy. Fortunately Don and Joe have done a fairly nice job of this kit. The manual could be a little better but that could be said about anything I guess. I found that the boom was really lose in F3 and F4 so I wrapped some glass around it using ca. I mentioned it to Joe and he said that was intentional to keep the boom from binding and not aligning correctly.
I think I might make a couple of changes like 1.0mm carbon control rods instead of the .08mm. And maybe I'll use 1/8" carbon tube for center section leading edge (just because).

Anyway I'll keep poking around your build thread and see what I can see.

Regards,
Dale
 

Konrad

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Anyway I'll keep poking around your build thread and see what I can see.

Regards,
Dale
I need to do the same. :sneaky:

May I ask why the D47s? I know they are tried and true. If I didn't already have a dozen of these D47s I think I would have gone with the HD 47G, unless running on a single cell Life battery. I think I stated that I'm running 6.6 volts (2 cell, Life 900 mAh).

I might be responsible for the opening up F3 and F4 by 0.10mm. That should not have necessitated a glass wrap

If planning the fly F3-RES keep in mind the total carbon content rule (I think this is a German limitation).
 

Gliderguy

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I need to do the same. :sneaky:

May I ask why the D47s? I know they are tried and true. If I didn't already have a dozen of these D47s I think I would have gone with the HD 47G, unless running on a single cell Life battery. I think I stated that I'm running 6.6 volts (2 cell, Life 900 mAh).

I chose the Dymond D47s because of size, voltage range (since I already have the 2s batteries) and I wanted analog (don't have a good reason for this yet). Also I've used them before, they're reliable and like them.

I might be responsible for the opening up F3 and F4 by 0.10mm. That should not have necessitated a glass wrap

Seemed way more than that but it worked out OK..

If planning the fly F3-RES keep in mind the total carbon content rule (I think this is a German limitation)

Good point although I doubt that I'll ever see a contest but maybe if it gets sold someday. I thought leading edge was OK though.

.
 

Konrad

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"I chose the Dymond D47s because of size, voltage range (since I already have the 2s batteries) and I wanted analog (don't have a good reason for this yet). Also I've used them before, they're reliable and like them."-Gliderguy

I too like these D47s.

In your Original Post (OP) you had a concern about centering. A big benefit of digital servos is that the digital amp is usually much more responsive than the old analog "op amp". This means that they center a lot better. Now the cost is that they are power hungry! Luckily for us we now have batteries that are 3 time the energy density of the great NiCads of old.

Another problem is if you have a dog in the shop. The digital servo has an almost constant whine as it holds center. This drives most pets insane.
 
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Gliderguy

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Ok, you have me rethinking again. Dimensions are pretty close. I could go with a different battery. I do remember now that centering was not that great on my old DLG with d47s but it wasn't a very accurate glider in a lot of ways. I don't know how much difference it will make on the Chrysalis lite. And if I did go for the cheaper servos I could almost afford an extra receiver.:unsure: No pets yet so..
 

Konrad

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You said you had a 2 cell, I had assumed it was LiFe chemistry not lipo. I've had real good luck with the LiFe 2 cell and the KS HD 47MG servo.

I liked my D47s in 100MPH speed 400 racers. Again I liked these old servos enough to still have over a dozen (NIB) in the bottom of my servo drawer. And those are what I'm using in my Chrysalis F3-RES build. So I think they are a good servo. Just that I wouldn't buy them today.

With the Chrysalis F3-RES there is a bit of room to make sound geometric hook ups (horns, arms and push rods). You will need to brace the nyrod a bit towards the front. The Chrysalis F3-RES really can't get fast enough to be an issue with high speed and low speed trim setting.

There is the HK voltage regulator Don and Joe often talk about to lower the voltage to use your RX. If running Fr-Sky your golden.
 

Gliderguy

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I think I can use a 5 cell pack of AAA Eneloop pro's if I do a little modding to the front top sheet. And I decided to go with the KS HD 47mg servos. More economic than anything. But the KS sound like they will do the job so I'll try them. Then I'll use a D4R-II. I had a pair of Turnigy TGY-90smg's but they were a little bigger size and weight than I wanted and also some Hitec HS 5045BB but they will fit in my DLG wing nicely.
Anyway thanks for the input.

Dale
 

Konrad

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They are rated at 7.4V which is the nominal voltage of a 2 cell lipo.

But like all servos the higher the voltage the shorter the life. More current through the motor brushes, the more wear on the commutator and brushes. What little you might give up in life expectancy you more than make up in performance.
 
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