How much servo torque & speed for pitch on R50 V2

[awr]

I apologize if I'm in the wrong forum, but I couldn't find an answer to this question after hunting for an hour.

My plastic friend is taking a beating from all the purchases one has to make to get started in this hobby so unfortunately I can't buy digital servos for my Raptor 50 - I'd have to take up permanent residence on the couch once my wife saw the bill.

I'm just getting into inverted flight and likely won't be flying 3D for at least another year - by which time I hope to have the experience to justify upgrading to expensive digital servos.

Can you please tell me what I should be looking for as a minimum recommended speed and torque
rating for the pitch servo?

Also, I'm running @ 6 volts to increase the torque and speed of my existing servos. Any worries with
doing this?

Thanks for the help.


Wayne
Calgary, Alberta

[vandelescrow]

As long as your servos are rated for 6 volt it's not a problem. Make sure you are stepping down the voltage for your gyro and tail servo. You can find the info you need on your servos at this link http://www.hobbylisting.com/html/servo/servo_frameset.html
A hint about this link, right click on the manufacturer and open in new window. Otherwise the chart will be so small at the bottom it will be unusable.

About what speed and torque for your pitch. Several people ask what I should get so I will list all the servos for anyone who reads this.

The following data comes from the book "Model Helicopter Aerobatics" by Russ Deakin originaly published in 2000 so I do not know if this data is still current with what we are putting our machines through today but it will get you in the ball park. Sorry he only lists 30 and 60 size machines

30 size speed torque
pitch 0.19 5.5 kg
cyclic 0.19 3.0 kg
tail 0.11 3.0 kg
throttle 0.22 2.0 kg

60 size speed torque
pitch 0.19 7.5 kg
cyclic 0.19 5.5 kg
tail 0.11 3.0 kg
throttle 0.22 2.0 kg

The speed is for 60 degrees

Hope this helps

[awr]

Thank you very much for the information.

My current servos are all Hitec:

HS-635 HB's on aileron & elevator .18/.15 sec 5.0/6.0 Kg
HS-625 MG - pitch .18/.15 sec 5.5/6.8 Kg
HS-645 MG - throttle .24/.20 sec 7.7/9.6 Kg
HS-5245MG - Tail rotor .15/.12 sec 4.4/5.5 Kg

The speed ratings for the throttle (yes, the torque is over-kill) and tail rotor servos are marginal at 4.8 volts (reason for going to 6 volts). The specs on the servo chart referenced on the above link show the HS-5245MG as .17/.13 sec @ 60 deg., but that's a mis-print as both the servo box and Hitec's website rate the servo at .15/.12 sec @ 60 deg.

My gyro is the GY-401. Engine is OS 50 Hyper

I have two concerns:

A) The servo speed on the pitch servo isn't well matched to the throttle.

I originally bought the HS-645MG as a pitch servo as in my mind I felt that the pitch servo needed to be quite strong on the raptor, given there's only one servo for collective.

I can't afford new servos, so is my present assignment correct, or should I switch the
pitch and throttle servos around?

B). Running 6 Volts on GY-401 Gyro

I know that there are several digital servos on the market that are dedicated tail-rotor servos which require a voltage step-down. Since I'm not using a dedicated tail-rotor servo,
do I still have to step down the voltage - the Futaba literature seems to indicate I can use 6volts on the GY-401 without damaging it.

I can't afford another Gyro so please let me know if 6 volts is a no-no with the GY-401.

Thanks again.

Wayne

[vandelescrow]

sorry about my last post, the second set of servo specs is for 60 size heli

[BarracudaHockey]

If you aren't interested in upping to digitals then those servos are fine.

[vandelescrow]

about the gyro, someone else best answer that, I have not had good luck with the 401. I had 2 and both tend to let the tail drift in a hover no matter how much gain I gave it. I'm now using the 611 in two of my birds and the JR G500T in my other two.

About the servos. Yes you want more torque on the pitch but I see if you switch the throttle servo with pitch, you will get more torque but a slower servo. You said in your last the the pitch does not seem to be matched to your throttle.

The speed and torque of the servos you have look fine for doing circuits. When you get into 3D, it would be best for someone else to answer that, I hate to give advice when I'm not sure.

[forjer]

...I see if you switch the throttle servo with pitch, you will get more torque but a slower servo. You said in your last the the pitch does not seem to be matched to your throttle....
Passing on something I read online (so it must be true) it's good to have a faster throttle than cyclic servos so the throttle responds before the pitch change loads the engine.

Would that be as critical if a governor is being used?

[vandelescrow]

forjer,
The Aerospire governor calls for a minumum .21 transit time for throttle and says a .10 - .16 would be ideal.

[awr]

Thanks for the great advice.

I think I'll switch the throttle and pitch servos so that I have more torque on pitch.
Later on I'll change the pitch servo for a faster servo and upgrade the tail rotor.

I called the Futaba Service Support line this afternoon to get their opinion. At first the technician didn't know what I was talking about - seems they get more calls about transmitters as he had no idea what a GY-401 was - I had to explain it to him.

Anyway, he got out the manual and read it to me - it said the GY-401 is designed for
4.8 volts, but if you use a higher voltage, it needs to be limited to 6 volts. I guess that
answers my question.

Thanks again for the great responses to this question.

Wayne

[vandelescrow]

Just remember that if you are using a 6 volt system, the battery at full charge is over 6 volt. I'm using a 7.2 volt battery and on a full charge it is around 8.4

[jschief]

Anyway, he got out the manual and read it to me - it said the GY-401 is designed for
4.8 volts, but if you use a higher voltage, it needs to be limited to 6 volts. I guess that
answers my question.



I think the Gyro can handle the higher voltage, it is the gyro servo like the s9254 that can not handle more than 4.8v or you will damage the servo.

[awr]

I made flight battery pack using 5 AA NiMh 2560 Mah batteries. A fully charged pack of 5 1.2 volt NiMh batteries is a bit more than 6 volts, but under load the voltage should be just about right. Have to watch the voltage drop over a few flights to ensure the performance doesn't suffer.

Thanks again for all the great feedback on this question.


Wayne