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HV Servos or not?

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Old 10-14-2012, 12:03 PM
  #1
ddennison
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Default HV Servos or not?

I am about to purchase some servos for a new project - SM Large Hawk.

I am wondering from those who have used them - if HV servos ( I happen to be a JR user) have been perfect or if there is any issue with them?

I will be running 2S lipo and would use a 1222 receiver.

Plan B is what I usually use - Weatronic receiver, same batteries and standard voltage servos.

Thanks in advance,
Dave
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Old 10-14-2012, 12:08 PM
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Greg Wright
 
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Default RE: HV Servos or not?

Dave,

I have been using the 8911 HV's in my BVM F-100 for two years now and i have not had 1 single issue with them at all. I'm running a Spectrum 12120 power safe receiver and two 5000 mh lipo's none regulated and it's a great set-up. I also have all the other surfaces and controls on HV servos. ABSOLUTLY NO ISSUES!!!!!!!!!!
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Old 10-14-2012, 12:11 PM
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John Redman
 
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Default RE: HV Servos or not?

I agree with Greg. Have been running them for years with no issues. Love them.
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Old 10-14-2012, 12:12 PM
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Default RE: HV Servos or not?

thanks Greg.

I hope to catch up with you sometime. I have family in Naperville and used to get to Winamac.

Thanks again for the info. I am planing on 8911s as well.

Dave
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Old 10-14-2012, 12:27 PM
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Default RE: HV Servos or not?

That is what I have for a winter project. All JR 8911 HV. Also trying electric retracts and a E brake. I have used 8911 HV in a couple of projects and have not had any trouble. Just got my Hawk and looking forward to the build. What are you using for a turbine.
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Old 10-14-2012, 12:51 PM
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Default RE: HV Servos or not?

I have a Jetcat 160Sx for the hawk. Goshawk for me. Where are you getting your electric-SM retracts?

Thanks
Dave
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Old 10-14-2012, 01:05 PM
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Default RE: HV Servos or not?

I am having Down and Locked do them. I was going to but a JC 160 in but used it on another project. So I guess it will be a JC 180.
I have a Tutor with a 160 and it could yse a little more power, maybe i'll change it with the 180. I have a new BAE display color scheme that the Brits cam out with this year.
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Old 10-14-2012, 01:16 PM
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Default RE: HV Servos or not?

Thanks - is the cost for conversion 1,2 or 3 times the cost of the valve and servo? I didnt know they where doing gear this big?

I am sticking with the 160Sx from what I have heard, read etc.

Dave
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Old 10-14-2012, 01:59 PM
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Default RE: HV Servos or not?

I am not sure of the cost I think it is in range of $600.
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Old 10-14-2012, 01:59 PM
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Default RE: HV Servos or not?

Dave I've got that set up in my Hawk and it works perfect except if your elevator swings over center and you turn on. It will instantly break a control arm. Not sure if anyone else has experienced this but it sucks. Super strong servos and nice not to have regulators. Your going to love the Hawk!!! Scott
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Old 10-14-2012, 02:16 PM
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Default RE: HV Servos or not?

Thanks Scott!
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Old 10-14-2012, 03:58 PM
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Default RE: HV Servos or not?

I've got 8 of the 8911HV on my UB, Dave, and one 8711HV on the N/G.....over 50 flights....no probs....JR also makes digital micro servos now with HV for retract and brake valves as well......

Originally I was running dual 7.4/4000 LiPo's into a 1222, but switched over to dual 2300/A123 for the last 20 or so flights.....IMO safer when charging, and field charging with a CellPro 10S dual output A123 charger at 4 amps re-loads them to 100% in the time it takes to refuel and pre-flight.

TA
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Old 10-14-2012, 04:05 PM
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Default RE: HV Servos or not?

Tom, And a lots cheaper too!!! Lipos don't forgive if you leave plugged up to the 1222 for 45 days! A123's don't care Scott
Expensive mistake!!
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Old 10-14-2012, 05:33 PM
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Default RE: HV Servos or not?

Tom,
With the a123 and 6.6 volts, do the HV servos care about the lower voltage?
DD
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Old 10-14-2012, 06:33 PM
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Default RE: HV Servos or not?

Not very much. They dont care that much but a little sad im sure.
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Old 10-14-2012, 07:01 PM
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Tom Antlfinger
 
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Default RE: HV Servos or not?

I noticed no change in speed with the 123's(they are very fast), but there is some loss of power from the 470 oz at 7.4 down to 200 oz at 4.8v. according to the spec page. So at 6.6v, presuming a linear drop, you still should have about 390 oz +/-

Spec page does mention A123/LiFe as suitable......

TA
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Old 10-14-2012, 07:11 PM
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Default RE: HV Servos or not?

Seems like SM Large Hawks with JR 8911's are all the rage Dave! Considering you are GIVING AWAY your UB (why ARE you selling her BTW???)

Anyways, my SM Hawk 100 was supposed to be here by now, and lo and behold, I of course have EIGHT 8911's coming with her along with A123 receiver packs from Electrodynamics and Andy Low.

Dave we should do our build together!!! Are you going to use the BVM manual?
Anyways, now that I crashed your HV servo thread (sorry), I would agree with Tom Antlfinger's extremely knowledgeable and well written post above. 8911 + A123's = winner combo!

Shaz
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Old 10-15-2012, 05:23 AM
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Default RE: HV Servos or not?

Quote:
ORIGINAL: Boating Bob

That is what I have for a winter project. All JR 8911 HV. Also trying electric retracts and a E brake. I have used 8911 HV in a couple of projects and have not had any trouble. Just got my Hawk and looking forward to the build. What are you using for a turbine.
Not to change the subject of the thead but who are you getting your e-brake from. Also the down n locked retract conversions work great. I have them in my gramunia me-262 and Tomahawk L-39. They work extremely well.
George
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Old 10-15-2012, 05:51 AM
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Default RE: HV Servos or not?


Quote:
ORIGINAL: Tom Antlfinger

I've got 8 of the 8911HV on my UB, Dave, and one 8711HV on the N/G.....over 50 flights....no probs....JR also makes digital micro servos now with HV for retract and brake valves as well......

Originally I was running dual 7.4/4000 LiPo's into a 1222, but switched over to dual 2300/A123 for the last 20 or so flights.....IMO safer when charging, and field charging with a CellPro 10S dual output A123 charger at 4 amps re-loads them to 100% in the time it takes to refuel and pre-flight.

TA
Hi Tom
Just a question here but if you are powering the 8911's with only A 123's why would you go to the extra expense of the 8911's over an 8711 when you can get 406oz. at 6 volts. Just curious are they quicker or for some other reason. One thing that Horizon is starting to show on their website though, is that the 8711 and 8411 are on the discountnued list, which I am not too happy about. I hope this is not true.
Thanks for your comments.
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Old 10-15-2012, 06:03 AM
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Default RE: HV Servos or not?

I am going to try a modified BVM E-Brake. I will use 2 cylinders on one mount with a large servo in the center. One cylinder pointed each way to operate one brake each. Mounted on the bottom under the intake
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Old 10-15-2012, 08:25 AM
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Default RE: HV Servos or not?

THE
Quote:
ORIGINAL: AKB


Quote:
ORIGINAL: Tom Antlfinger

I've got 8 of the 8911HV on my UB, Dave, and one 8711HV on the N/G.....over 50 flights....no probs....JR also makes digital micro servos now with HV for retract and brake valves as well......

Originally I was running dual 7.4/4000 LiPo's into a 1222, but switched over to dual 2300/A123 for the last 20 or so flights.....IMO safer when charging, and field charging with a CellPro 10S dual output A123 charger at 4 amps re-loads them to 100% in the time it takes to refuel and pre-flight.

TA
Hi Tom
Just a question here but if you are powering the 8911's with only A 123's why would you go to the extra expense of the 8911's over an 8711 when you can get 406oz. at 6 volts. Just curious are they quicker or for some other reason. One thing that Horizon is starting to show on their website though, is that the 8711 and 8411 are on the discountnued list, which I am not too happy about. I hope this is not true.
Thanks for your comments.
The 8711HV is a better servo, and more expensive than an 8911HV. the 8911 is a plastic case, where the 8711 is an all aluminum case. Toms UB has the better 8711HV servos from tip to tail.
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Old 10-15-2012, 10:23 AM
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Default RE: HV Servos or not?

Geeeez! Senility is really setting in......just passed #70 couple of weeks ago......Guess it is time to sell my jets and stick to my 1oz indoor heli's...[]

Kirk knows what is in the UB as Kirk built the plane and I bought it RTF.......I remembered the 8711 HV on the N/G, but somehow got locked on to the 8911's. Just had the flap servo and aileron covers off last week, looking straight at 8711 HV's...

In any case, the presumed linear drop in 8711HV motor power should be the same as the 8911HV.....as power is near identical to 8911, they may be using the same motor?

Thanks Kirk......

Good question AKB......I bought the UB RTF with the 8711HV servos installed with 2 Lipo Bats.......
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Old 10-15-2012, 11:59 AM
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Default RE: HV Servos or not?

If you guys want some serious servo power take a look at the JR 6301, metal cased servos, the HV version, the 6311, take upto 8 .4 v but are rated at 7.4 V for 36.5kg/cm , 40% up on 8911s. A reduction to 6v drops the torque about 10% .
Using those on the stabs and flaps on my SG Hawk. MP80Ts, brushless, on ailerons, very active with a gyro in operation.

With a Weatronics system one can select the voltage to groups of servos, perfect.

See www.rcjapan.net

Don't give up because you're 70 Tom you're ahead of me, my pathfinder !

Regards,

David G.
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Old 10-15-2012, 02:09 PM
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Default RE: HV Servos or not?

Double post....
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Old 10-15-2012, 02:10 PM
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Default RE: HV Servos or not?


Quote:
ORIGINAL: Andrew Bird

I've been using 8711HV's and 8911HV's (also some 6311's when in Europe) for a while now in a mixture of planes, but mainly 40% IMAC / 3d aircraft. I have managed to wear out the cases on the 8911 HV's in those applications (but no such issue with the metal cased 8711HV/6311) pretty quickly and the servos get sloppy but I suspect the loads on a jet with smaller surfaces, lower travel and shorter servo output arms would be fine. I use MP80t's on my Ultra Bandit and have found them brilliant. There are no issues with case wear and it's basically the same case as the 8911HV.
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