Tail Servo?

[c00lhands]

So I ordered a Futuba S9650 hoping to use it on my tail. Was I ever surprised to discover that it is too small for the Hurricane 550 :arggg:. So it looks like I threw $55 down the drain. I need to get a proper servo for my tail. I ordered the Futaba S3151 for the cyclic servos and was wondering if its adequate for the tail? If it wont do the job can you recommend one that will do the job that wont break the bank. The S9254 that Finless is using in his video is a little pricey for me right now. As you can tell I'm a n00b, so I'm not going to be doing any fancy flying. Thanks for any input

[mysticmead]

you can use the 9650 with the hurricane.. you just need the boom servo mount

[Pinecone]

Or get a servo adapter plate from ReadyHeli.

[Drew816]

3151's for the Cyclic?? 3151 specs:

4.8V 43.0 oz-in. 0.21 sec/60°
6.0V 54.0 oz-in. 0.17 sec/60°

DS821 Specs:

Torque:72 oz/in @ 4.8v, 88 oz/in @6v
Speed:.19 sec/60° @ 4.8v, .15 sec/60° @ 6vJust saying, the more power the better so you might want to consider rethinking all this and getting servos that will fit easily in the Gaui frame and are proven performers let alone CHEAP! I got 4 brand new 821's for $80 shipped with all the parts and pieces...

Just a thought. I like the 9650, I have one on my T-Rex 450 but I wouldn't consider using it on the Gaui.

[Pinecone]

I have bought two sets of DS821s for about $60 each. Check the classifieds and make offers. People ask around $80, but will sell for less.

[c00lhands]

At this point I'm pretty much stuck with the 3151's for now. Is it a bad idea to mount these servos for rookie flight or will they be adequate for now? At this point i'm only talking about hovering. I'll look into the 821 for the tail.

[c00lhands]

you can use the 9650 with the hurricane.. you just need the boom servo mount

Mysticmead I noticed you were using a boom mounted tail servo on your 550. What servo are you using?

[mysticmead]

Mysticmead I noticed you were using a boom mounted tail servo on your 550. What servo are you using?
using DS821 servos for tail and cyclic

[mysticmead]

At this point I'm pretty much stuck with the 3151's for now. Is it a bad idea to mount these servos for rookie flight or will they be adequate for now? At this point i'm only talking about hovering. I'll look into the 821 for the tail.


any servo that fits and gets you in the air at this stage will work. upgrade as you can..

[Crashed Monkey]

3151's for the Cyclic?? 3151 specs:

4.8V 43.0 oz-in. 0.21 sec/60°
6.0V 54.0 oz-in. 0.17 sec/60°

DS821 Specs:

Torque:72 oz/in @ 4.8v, 88 oz/in @6v
Speed:.19 sec/60° @ 4.8v, .15 sec/60° @ 6vJust saying, the more power the better so you might want to consider rethinking all this and getting servos that will fit easily in the Gaui frame and are proven performers let alone CHEAP! I got 4 brand new 821's for $80 shipped with all the parts and pieces...

Just a thought. I like the 9650, I have one on my T-Rex 450 but I wouldn't consider using it on the Gaui.
Hi drew ,is the s9257 servo ok for the tail ? Can you put 6v through it? cheers Andy

[yuktong]

I found that my 9254 is very hot after each flight, is it normal in 550?
My 9257 didn't get any warm on my mini titan

[xodarap1]

My 9254 only gets warm, but not hot.

-Check the tail and linkage for any binding. The high torque servo may mask a binding issue and cause it to run hot.
-Pop the push rod off and carefully check the tail slider range of motion for any binding. It should be smooth with no notchiness (is that a word?) :)
-Does it still run as hot with the gain turned down.. or in analog mode?
-Is there excessive vibration on the heli that would cause the gyro to overwork?

*My 9251 gets very warm (i wouldn't say hot)..but it has a heat sink built into the servo case and the manual said the higher temps (on the 9251) are normal.

[yuktong]

it was hot even in analog mode:arggg:

[ukgroucho]

You're not running 6v through it are you? The 9254 is only rated for 5v.

[yuktong]

sure, i got the step down cable
also, i check that there is no binding
it makes me so confused~~~

[kahn10]

for an eye opener....... next time you've got the head off a chopper - any chopper - spin her up with your tail servo disconnected (while holding securely) and see how much effort it takes to move it out of neutral. you will be amazed how much work your tail servo does. hence the chinese weight mod :thumbup: by moving outa neutral i mean grab the tail control rod and BE THE SERVO........

[yuktong]

for an eye opener....... next time you've got the head off a chopper - any chopper - spin her up with your tail servo disconnected (while holding securely) and see how much effort it takes to move it out of neutral. you will be amazed how much work your tail servo does. hence the chinese weight mod :thumbup: by moving outa neutral i mean grab the tail control rod and BE THE SERVO........

thx for your suggestion
but where could i find the suitable chinese weight?

[kahn10]

its something you have to build yourself bro......search the threads do some research.......plenty of info available ;)

[Pinecone]

Chinese weights are not normally needed for plastic tail grips, mainly for the metal ones. You are counteracting the effect of the mass of the tail grip arm and ball.

And how how is hot on your servo? Hot enough to burn instantly, or hot enough to have to remove your finger after a few seconds?

I would not runa 9257 on a Hurricne, too low of torque. And I would not run a DS821 on the tail, way too slow.

9254 (can be pretty cheap used in the classifieds), 8900G. But you want the tail servo to be down around 0.10 second speed, at least.

[Drew816]

So what are THE tail servos to run on the Gaui 550? 8900G, maybe 8700, 9254 (if 5 volts only of course), what else?

I'm running at 6 volts and was thinking 8900G but PHEW, they ain't cheap!

[Pinecone]

Pretty much all tail servos need a step down.

You could run a DS3400G on 6 volts, but will need a boom servo mount or an adapter plate.

But the 8900G is amazing. I have one in my Vibe 50 (still building) and I hooked up the gyro and was twisting the gyor just watching the servo moe, or at least trying to watch, the arm was a BLUR.

Some people have run the S9254 without a stepdown, but others have reported problems.

But a stepdown is cheap to make. All you need is a pack of 1N4001 diodes from Radio Shack. Install one in the middle servo wrie, with the band towards the servo.

[mysticmead]

you could get the Hyperion DS20GMD for a blinding fast tail servo... cheap too
http://www.allerc.com/product_info.php?cPath=40&products_id=3489

[Drew816]

MM, have you tried these servos specifically for the tail on the Gaui 550???

http://www.convertunits.com/from/ounce-inches/to/kilogram-centimeters

http://media.hyperion.hk/dn/at-ser/ATLAS-MAN-EN-PG1-070622.pdf

At 6 volts the Atlas DS20GMD servo is only putting out 27 oz/inches of torque at 0.05 travel, I would think that would not be NEAR enough for a tail servo for the Gaui 550.

The HMD is putting out 65.3 at 6v and moving at 0.11, and the FMD is putting out 113.9 at 6v traveling at 0.13. So the HMD seems to be the best of the Atlas units for speed but still a little under spec'ed for torque; or is it?!?. Of course they're $39 so there is THAT to be considered! The FMD is a little slower at 0.13 but MAN look at that Torque! Plus it's only $36... Humm, might be worth considering...

In comparison the JR DS8417 tail servo unit which is $115, 98 oz/inches 0.08 seconds at 6 volts.

http://www.jrradios.com/Products/TechnicalSpecs.aspx?ProdID=JRPS8417

The 8717 is 196 oz/in at 0.07 at 6 volts and $110 designed for the cyclic but I would suspect it would work fine for the tail:

http://www.jrradios.com/Products/TechnicalSpecs.aspx?ProdID=JRPS8717

Of course the afforementioned 8900G at 4.8 volts, 48 oz/in torque and 0.05 travel for speed; WOW! And in their specs they're saying that this is big enough for a 600 sized helo; MAYBE the torque numbers don't need to be so high after all??? And I have a 5.1 v drop down available so no worries there for me...

http://www.jrradios.com/Products/TechnicalSpecs.aspx?ProdID=JRPS8900G

For the sport flier this ultra speed is probably overkill, I'd think torque and a reasonable amount of response would be good enough; right? With a DS821 on the tail of my Gaui now I'm only getting 88 oz/in and 0.15 at 6 volts so I'm thinking the Atlas FMD for $36 would get me a lot more torque and a little quicker response for $36.

Thoughts? I'm confused, Torque or Speed, what's it gonna be?!?

[mysticmead]

the DS20GMD should be plenty for the tail. I really don't think you need huge amounts of torque on the tail.. speed is needed though

[Drew816]

Mystic, are you using a GMD on your tail? Who here is? It has have the torque of a 9650 Futaba but MAN that speed is amazing! Of course several of the JR servos have it all, but at nearly 4 times the cost too...

I was under the impression you needed torque and holding on the tail servo; certainly speed is a good thing but... I would think the GMDs would be working REALLY hard on the Gaui.

Thoughts, direct experiences???