9650 with 9257: Truly a lightning !!

[enry74hh]

On my Mini Titan I used on the tail servo Futaba S9650; A few weeks ago I ordered the new S9257.
Indeed, the 9650, while running on 6V, with significant variations in pitch was a little effort to respond promptly. (Eg varying fast pitch with the eli in hovering tail mentioned to rotate a little).

The new servo works at 4.8V therefore, not wanting to lose the 6V on cyclical, I had already prepared a stepdown.

Once arrived servo I see that the case is identical (dimensional) to the case of 9650, will open two servo and find a complete interchangeability of gears.

By analyzing in detail is the first 2 gears (those to the engine) having a different number of teeth even if all have the same distance .. Exactly:

S9650: 38/12 ratio 3166
S9257: 30/20 ratio 1.5

The technical data of the servo are:

S9650 4.7 kg - 0.11 s (6V)
S9257 2 Kg - 0.08 s (4.8 V)

Assuming to mount the gears of S9257 on the S9650 should be:

3.166 / 1.5 = 2.11

0.11 s / 2.11 = 0.052s
4.7 kg / 2.11 = 2.22 Kg

So the result is a servo who pulls 2.2 Kg with 0052s speed.

Okay, I decide to do this test, assemble everything, and I go flying: the result is a net reduction of that movement that occurred in coincidence of abrupt changes of pitch. Performing the tic toc tail remains firm.
Now I have to decide whether to take this solution and judge reliable or not.

To see get tail-blade but comes to mind a beautiful 9254; is a lightning.


What do you say?

(Sorry for my English incorrectly)

Enrico.

[uragano47812]

Ciao Enrico, i have try the sl-720 with not so great result with s9257 on Minititan. But with s9650 on 6V no problems at all even in really faster rear flight. so i think that the stronger s9650 is better than the a little faster s9257.

Let me know how is your experiment.

Thanks
Adriano

[enry74hh]

I made a mistake in counting the teeth of the gears.

The data are correct:

S9650 35/12 = 2.92

S9257 29/18 = 1.61

Ratio = 2.92/1.61 = 1.81

The Futaba S9650 with the gears of the S9257 has:

Torque 4.7/1.81 = 2.6 Kg
Speed 0.11/1.81 = 0.06 s/60 °


These days I did other flights and confirm that I am very pleased with this change.

Enclose a photo of the tail rotor. The two small weights help the servo.


( ciao Adriano; io non faccio 3D duro ma nelle classiche figure Tic Toc, retro veloce, ecc la mia coda con questo servo modificato unito al "bilanciamento del ruotino" è migliorata rispetto all'utilizzo del S9650 standard. Ad oggi ho fatto circa 10 voli e assolutamente nessun problema. Ciao Enrico)

[ecofan_]

Hi,

Are you running your servo @4.8V or @6V ?
As I've already got a 9650 and a 9257, and have some troubles with my tail (csm720/9257) I'll probably try !

First thing 'll be to try another hole on the servo horn


Nicolas

[enry74hh]

Hi,

The 9650 Changed do operate at 6V; The gyro is GY401.
For your problem you tried to add the two weights on the screws? (See photo 2)

By.

[Finless]

enry74hh, why did you report this post to helifreak admins? I dont see a problem? Was it a mistake?

Bob

[enry74hh]

enry74hh, why did you report this post to helifreak admins? I dont see a problem? Was it a mistake?

Bob


Sorry it was a mistake.
Enrico.

[dennis22g]

Hi guys, Someone who knows about the 9650, I am having problems with my combo of gy401 and the 9650. When on normal mode,,, I have adjusted the throw - perfect.
When I go to HH mode the throw goes to the stops and then slowly creeps further.
I have tried my s3107 and a HDS 877. All are the same. Is this normal?

Dennis.

[miguelcpp]

Can someone tell me if i need a stepdown for the modified s9650, or it will work with 6v like stock???

thanks, Jose Miguel

[mkoutnik]

Hi guys, Someone who knows about the 9650, I am having problems with my combo of gy401 and the 9650. When on normal mode,,, I have adjusted the throw - perfect.
When I go to HH mode the throw goes to the stops and then slowly creeps further.
I have tried my s3107 and a HDS 877. All are the same. Is this normal?

Dennis.

The 401 does not sense the neutral position. From RC Heli magazine, "TIP! With the rudder stick centered, you may observe that the rudder servo walks to one end when the gyro is in heading hold mode. If it does AND you're sure there isn't any trim or sub-trim dialed in, your gyro does not sense neutral but rather expects a specific neutral pulse width. Should this be the case, just dial in opposite direction sub-trim until the walking stops. You should also note that it may be temperature sensitive and could require subsequent adjustments."

Here's the whole article...http://www.rchelimag.com/pages/howto.php?howto=14&page=1

[rcbrucelee]

I have read threads on this mod to the 9650 several places and I couldn't find any 9257's so I purchased a couple of the 9257 gear sets and I also bought a trex 5.1 stepdown because I couldn't find out if it was the same motor or not. I've had 5 flights on the new setup with my trex450, turned up my 401 10 points before any wagging and its locked in comparison to stock 9650, I'm stil waiting to see if its the same motor cause I haven't owned a 9257 yet lol

[uragano47812]

I have read threads on this mod to the 9650 several places and I couldn't find any 9257's so I purchased a couple of the 9257 gear sets and I also bought a trex 5.1 stepdown because I couldn't find out if it was the same motor or not. I've had 5 flights on the new setup with my trex450, turned up my 401 10 points before any wagging and its locked in comparison to stock 9650, I'm stil waiting to see if its the same motor cause I haven't owned a 9257 yet lol

If you put the 9257 on a 9650 servo you can run it at 6V because 9650 can handle it.

But also 9257 can run on 6V if REGULATED (with BEC). Instead for example not on 6V NiCD-NiMH which are about 7V when charged (as 9650).

So you can remove your stepdown.