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Old Sep 01, 2011, 12:37 AM
Team JetiUSA
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Santa Clara, CA
Joined Nov 2008
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Originally Posted by kcaldwel View Post
I'm interested in opinions on the best servos for this size of Osiris?

I have Hitec HS65MG and HB servos, but a bit more precision on the centring is probably desirable. I can't see any JR or Futaba servos that are in the same range as the HS65.

These are the servos that seem to be in the same weight and torque range as the HS65:

http://www.servodatabase.com/compare...1560,1868,2108

I've had a poor experience with the smaller Spectrum digital servos, does anyone have any experience with the A3040? I'm thinking the Hyperion may be the best bet, or does the Hitec 5065MG centre well?

Thanks,

Kevin
I'd think the JR 3421 would be good replacements for the HSxx65 servos, and they center WAY better. For precision I won't buy Hitec 5's or 7's anymore, though my 7955TG is decent, it's not as good as the JR 9411 I used for a rudder servo in what is now my primary 62" Osiris.

Peter+
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Old Sep 01, 2011, 01:57 AM
scratch-built
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United States, WA, Port Orchard
Joined Apr 2007
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Quote:
Originally Posted by kcaldwel View Post
I'm interested in opinions on the best servos for this size of Osiris?

I have Hitec HS65MG and HB servos, but a bit more precision on the centring is probably desirable. I can't see any JR or Futaba servos that are in the same range as the HS65.

These are the servos that seem to be in the same weight and torque range as the HS65:

http://www.servodatabase.com/compare...1560,1868,2108

I've had a poor experience with the smaller Spectrum digital servos, does anyone have any experience with the A3040? I'm thinking the Hyperion may be the best bet, or does the Hitec 5065MG centre well?

Thanks,

Kevin
I've flown and am still flying 25e size pattern planes on Hitec HS-65HB and MG servo's. Aspera, Vanquish, and Helios. Lately, I've been putting Digital servo's in my Planes, both Pattern and Scale. My Osiris 62" and 47" are two of the pattern planes in which I have Hyperion Digital Servos.

I have HP-DS16-FMD servos on the Ailerons and El and a HP-DS20-FMD on Rudder of the 62" Osiris.

On the 47" Osiris, I have HP-DS11-AMB servos on all surfaces. The Atlas servos in both planes seem to be doing a good job of controlling the planes. They are both fast and precise. Only time will tell as to how long they will continue to perform in this fashion.

I have many, many, flights on the Osiris 62" with these Atlas servo's without a whimper out of any of them. I wouldn't hesitate to use them in any of the planes I have.

The 47" Osiris hasn't had as many flights as the 62" Osiris, But I've only had it a little over a month. It's as much fun to fly as the 62".

That's just my experience with the Hyperion Atlas Servo's, Your Opinion and mileage may vary.

J
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Old Sep 01, 2011, 02:05 AM
When in doubt, gas it!
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United States, KS, Spring Hill
Joined Dec 2010
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Quote:
Originally Posted by Jim Lee View Post
I've flown and am still flying 25e size pattern planes on Hitec HS-65HB and MG servo's. Aspera, Vanquish, and Helios. Lately, I've been putting Digital servo's in my Planes, both Pattern and Scale. My Osiris 62" and 47" are two of the pattern planes in which I have Hyperion Digital Servos.

I have HP-DS16-FMD servos on the Ailerons and El and a HP-DS20-FMD on Rudder of the 62" Osiris.

On the 47" Osiris, I have HP-DS11-AMB servos on all surfaces. The Atlas servos in both planes seem to be doing a good job of controlling the planes. They are both fast and precise. Only time will tell as to how long they will continue to perform in this fashion.

I have many, many, flights on the Osiris 62" with these Atlas servo's without a whimper out of any of them. I wouldn't hesitate to use them in any of the planes I have.

The 47" Osiris hasn't had as many flights as the 62" Osiris, But I've only had it a little over a month. It's as much fun to fly as the 62".

That's just my experience with the Hyperion Atlas Servo's, Your Opinion and mileage may vary.

J
I have Hyperion Atlas digitals all around on my T-Rex 500 and they have been performing awesome. For the really small planes, I've been using the Hitec analogs, but I think I will be getting Hyperions for some of the bigger planes that I have on my "to get" list.

That's just my experience with them, your opinion and mileage my vary.
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Old Sep 01, 2011, 07:24 PM
agnotology
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Thanks for the recommendations for the Hyperion DS11 servos. It sounds like they may be the best of the 11 gram range of servos for these smaller pattern airplanes.

I have just finished my home made digital throw meter, so I'll test the Hitec HS65MG and HBs I have. Hopefully I can update to some Hyperion DS11 servos soon, and compare the results.

I'm struggling with the logic of the cable pull-pull rudder, at least on the little Osiris. It seems to be overall heavier than just putting the 11g rudder servo in the tail. I guess it might trim a bit of tail weight and inertia, at the expense of a much poorer connection between the servo and the rudder. Maybe it makes sense on the bigger airplanes when the alternative is another 60g or 80g servo in the tail or some cables, but when you are using 11g servos?

Kevin
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Old Sep 01, 2011, 08:44 PM
Team JetiUSA
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Santa Clara, CA
Joined Nov 2008
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Quote:
Originally Posted by kcaldwel View Post
Thanks for the recommendations for the Hyperion DS11 servos. It sounds like they may be the best of the 11 gram range of servos for these smaller pattern airplanes.

I have just finished my home made digital throw meter, so I'll test the Hitec HS65MG and HBs I have. Hopefully I can update to some Hyperion DS11 servos soon, and compare the results.

I'm struggling with the logic of the cable pull-pull rudder, at least on the little Osiris. It seems to be overall heavier than just putting the 11g rudder servo in the tail. I guess it might trim a bit of tail weight and inertia, at the expense of a much poorer connection between the servo and the rudder. Maybe it makes sense on the bigger airplanes when the alternative is another 60g or 80g servo in the tail or some cables, but when you are using 11g servos?

Kevin
Pull-pull on a LARGE surface like the Osiris' rudder is much more effective at preventing blowback than a single servo doing push/pull control. Also, the pull/pull cables allow the control horn to be essentially centered on the control surface, so you get less warping of the surface under load than you would with a push/pull servo that would be connecting near the bottom of the surface.

Peter+
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Old Sep 01, 2011, 09:04 PM
agnotology
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Joined Jan 2007
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Quote:
Originally Posted by pvogel View Post
Pull-pull on a LARGE surface like the Osiris' rudder is much more effective at preventing blowback than a single servo doing push/pull control. Also, the pull/pull cables allow the control horn to be essentially centered on the control surface, so you get less warping of the surface under load than you would with a push/pull servo that would be connecting near the bottom of the surface.

Peter+
Maybe I'm missing something, but if you use the same servo and the same mechanical ratios, wouldn't the servo see the same blow-back loads whether it was connected with cables or a solid push rod?

The little Osiris at least has the cables connected near the bottom of the rudder.

I also discovered there is another cut-out for a rudder servo in the tail on the mini-Osiris, so I think I'll move my rudder servo back there.

Kevin
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Old Sep 01, 2011, 09:11 PM
Advocating for RC Aviation
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That's probably not a rudder servo cutout - probably the mirror image elevator cutout as the sides are likely symmetrical. This is how 3DHS builds AJ Slicks so probably also true for Osiris. Good luck. Dana
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Old Sep 01, 2011, 11:48 PM
agnotology
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Originally Posted by danamania View Post
That's probably not a rudder servo cutout - probably the mirror image elevator cutout as the sides are likely symmetrical. This is how 3DHS builds AJ Slicks so probably also true for Osiris. Good luck. Dana
It's aft of the elevator servo cut-out, and on the other side of course. The servos don't over lap at all, so I think it is there for a rudder servo. Mine has one mounted in it now anyway!

Kevin
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Old Sep 02, 2011, 12:04 AM
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Originally Posted by kcaldwel View Post
It's aft of the elevator servo cut-out, and on the other side of course. The servos don't over lap at all, so I think it is there for a rudder servo. Mine has one mounted in it now anyway!

Kevin
I'm just guessing here, but I've seen on other smaller 3DHS planes where there was an option to do pull/pull, or put the rudder servo in the back. The reason for the option was that if you were running a lighter power setup, then you wanted to use pull/pull to keep the weight out of the tail. If you were running a heavier power setup, then you wanted to put the servo in the tail.

I'm assuming that when they originally designed it they put a cutout for a tail rudder servo in there in case they needed it.

I suppose you will know for sure once you start trying to set the CG!
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Old Sep 02, 2011, 02:18 AM
agnotology
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Quote:
Originally Posted by KTMRacr View Post
I'm assuming that when they originally designed it they put a cutout for a tail rudder servo in there in case they needed it.

I suppose you will know for sure once you start trying to set the CG!
I'll have to shift my 240g battery pack forward 30mm to compensate for moving an 11 gram servo back 640mm, assuming all the hardware weights are a wash. I think there should be enough range in the battery pack mounting to allow that. I guess we'll see, but the rudder seems much more solid at least.

Kevin

Edit: It looks like it balances with a Hitec HS65 rudder servo in the tail without a problem, even with a light (130g) motor and small 2200mAh 4S battery.
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Old Sep 03, 2011, 01:35 PM
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Will a Hacker A30-12XL fit?

I'm using the older VI 770kv in my Aspera on 4s2650 with a 12x6
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Old Sep 03, 2011, 04:33 PM
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United States, WA, Port Orchard
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Originally Posted by 732002 View Post
Will a Hacker A30-12XL fit?

I'm using the older VI 770kv in my Aspera on 4s2650 with a 12x6
The A30-12XL is a wee bit longer and over a ounce heavier then the recommended A30-14L and it's a tight fit.http://www.aero-model.com/Hacker-Bru...-A30-12XL.aspx
http://www.aero-model.com/Hacker-Brushless-A30-14L.aspx
You probably will have to enlarge the motor shaft opening in the cowl to have enough clearance for the prop adapter.

I used the Omega 130g870 motor in my 47" Osiris and it was a tight fit. I would have liked to see the 47" Osiris set up the way the 62" Osiris is. The motor box is short enough in the 62" Osiris to allow the use of spacers to accommodate your choice of motors.

J
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Old Sep 03, 2011, 06:43 PM
agnotology
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I just had my first flights on my little Osiris. Wow, what a nice airplane! It flies like it is much bigger, and like it is on rails. I am very happy with it. I find it flies much nicer than the little Vanquish I had, may it rest in peace.

I had some help getting it tuned up this afternoon (thanks Murray!), and we ended up with the CG at 127mm aft of the LE at the fuse junction, which is 2mm farther back than the aft limit in the instructions. With the CG that far aft, the elevator is quite sensitive and we are down to +/-10 degrees on the elevator. I ended up with the battery and receiver aft of their initial positions, even with the rudder servo in the tail.

The 130g Pulso motor I am using seems quite good for pattern type flying, with 2150 and 2200mAh packs.

Last night I was misreading my new digital throw meter without my glasses on, and thought I was seeing several degrees of neutral error. Worst case I can see today is perhaps 0.3 degrees at the surface, and and I am hoping that will come down when I revise the linkages for the smaller throws that I am using. Maybe the analog Hitec HS65MG aren't that bad. The HB I have on the rudder seems to be the best of the four.

Kevin
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Old Sep 03, 2011, 08:48 PM
scratch-built
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United States, WA, Port Orchard
Joined Apr 2007
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Quote:
Originally Posted by kcaldwel View Post
I just had my first flights on my little Osiris. Wow, what a nice airplane! It flies like it is much bigger, and like it is on rails. I am very happy with it. I find it flies much nicer than the little Vanquish I had, may it rest in peace.

I had some help getting it tuned up this afternoon (thanks Murray!), and we ended up with the CG at 127mm aft of the LE at the fuse junction, which is 2mm farther back than the aft limit in the instructions. With the CG that far aft, the elevator is quite sensitive and we are down to +/-10 degrees on the elevator. I ended up with the battery and receiver aft of their initial positions, even with the rudder servo in the tail.

The 130g Pulso motor I am using seems quite good for pattern type flying, with 2150 and 2200mAh packs.

Last night I was misreading my new digital throw meter I just made without my glasses on, and thought I was seeing several degrees of neutral error. Worst case I can see today is perhaps 0.3 degrees at the surface, and and I am hoping that will come down when I revise the linkages for the smaller throws that I am using. Maybe the analog Hitec HS65MG aren't that bad. The HB I have on the rudder seems to be the best of the four.

Kevin
kcaldwel, Congratulations on your successful maiden of the 47" Osiris. The more you get it dialed in, the more you are going to love flying it.

I take both my 62" and 47" to the field and They are both great flying airplanes, but when the other fliers see the 47' Osiris, They can't believe how well it flies, compared to the 62" Osiris, Which is a real beast on 6s.

J
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Old Sep 04, 2011, 10:10 AM
I hate winter!
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Canada, ON, Barrie
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Originally Posted by pvogel View Post
..on this critical rare earth metal have gone up 1500%, and without neodynium you don't have a brushless motor.
It's actually no more rare than cobalt, nickel, and copper. However companies keep using the word 'rare' as a price adjuster. However, looks like the Chinese mine it, so they can lock it down It's obvious they do this because of the wave of full sized electric vehicles. RC really means nothing to them, but full sized cars mean $$


As per wikipedia: http://en.wikipedia.org/wiki/Neodymium

Although neodymium is classed as a "rare earth", it is no rarer than cobalt, nickel, and copper are, and is widely distributed in the Earth's crust.[2] Most of the world's neodymium is mined in China.

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