tailskid2
Feb 24, 2005, 02:00 AM
!Introduction
| spec2
| @912085
|> <b>Model Number:</b> |< HS-755HB
|> <b>Application:</b> |< 1/4-scale-type aircraft
|> <b>Weight:</b> |< 3.38 oz. (110g)
|> <b>Size:</b> |< 2.32x1.14x1.96" (59x29x50mm)
|> <b>Torque:</b> |< 152 in oz @4.8v (11 kg cm)<br>183 in oz at 6.0v (13.2 kg cm)
|> <b>Speed:</b> |< .28 sec/60 @ 4.8v<br>.23 sec/60 @ 6.0V
|> <b>Manufacturer:</b> |< <a href=http://www.hitecrcd.com>Hitec</a>
When it comes to servos for large models, torque ratings seem to get the most attention, closely followed by price. Hitec has introduced a ¼ Scale Servo that offers not only a very acceptable torque rating, but a consistent centering servo for a price that rivals most ‘Standard Servo’s!
Albeit on the large size, this servo surprised this reviewer with its reliable centering ability. Add to this fact the quiet nature of the HS755HB, I feel this is one very good value. Yes, it weighs more and is larger than some of the $100+ servos, but when a giant scale plane requires 6 or more ‘strong’ servos, one can’t deny cost becomes a factor. I don’t know about you, but spending $600-$700 just for servos alone can dictate whether or not I can proceed along that level of the hobby.
@912086:Side-by-side with the competition...
@912087:if size and weight aren't crucial, then you may not need to pay the JR pricetag!
I compared the HS-755HB servo with my friend’s favorite JR 8611. The size difference was quickly apparent and the JR 8611 won in both the torque ratings as well as the speed needed to move the servo arm the proverbial 60 degrees. Of course the JR8611’s cost of $115 makes it possible to purchase almost four HS-755HB servos for one JR 8611! So, for models where the little larger size and little less torque aren't significant, I'd go for the HS755HBs!
*Special Features:
*Karbonite gear train;
*Dual Ball bearing;
*Water and Dust tight;
*Connector lead: 12” and color coordinated;
*5 Heavy Duty servo arms supplied;
*Molded rubber shock mounted grommets.
!Testing
@912088:Testing the centering...
@912089:...note the straw's accuracy, at 8" from the servo!
!!Centering
To test the servo, a quick solid wood frame was built and the servo was mounted with the supplied hardware. JR’s 1100 mAh 4.8-volt battery connected the servo to a HiTec Electron 6 Mini-receiver. The transmitter used was a JR XF421 as that was readily available to me at the moment.
The first test was to evaluate the centering quality of the servo. Using a large 8” soda straw attached to one of the supplied servo arms, 50 “trials” were attempted. Twenty-five trials were done by moving the aileron joystick full left and then permitted to return to neutral. Moving the transmitter stick to a full right position followed each of these movements. The transmitter stick was permitted to return to neutral while under the gentle pressure of my fingers.
By remaining sitting in the same position, the final resting position of the straw was carefully observed. Only one time did the straw not return to its initial position, and that was by less than 1/16”. Remember, this measurement was 8” from the servo arm!
Needless to say, I was impressed with this degree of accuracy.
!!Torque
The next test was to evaluate the torque rating. A wire pushrod was configured to hold some lead weights and connected to the servo 1” from the center. With the wood frame mounted vertically, the servo was asked to ‘lift’ various weights. The torque rating indicated 152 oz./inch. That’s a total of 9.5 POUNDS! To be honest, I never asked this servo to lift more than 128 ounces for two reasons: 1) the pan holding the weights couldn’t hold anymore and 2) I ran out of use-able weights.
Many times the servo would groan with pain as weight was lifted – a groan similar to the sound you get when you tighten the servo arm screw. But lifted it did! I didn’t notice any deterioration in the speed of the servo during these tests.
I’m sure the current draw escalated tremendously when this was done, but the necessary equipment needed to document this wasn’t available to me at that time.
!Conclusion
The servo hasn't yet had an opportunity to be flight-tested because the plane needed for this servo wasn’t available. However, in my humble opinion, this servo should do very well at the job it was intended for – guiding ¼ scale planes around the sky. I will not hesitate using it on my next ¼ scale project!
There are three types of people in this world...those who can count, and those who can't!!!!
| spec2
| @912085
|> <b>Model Number:</b> |< HS-755HB
|> <b>Application:</b> |< 1/4-scale-type aircraft
|> <b>Weight:</b> |< 3.38 oz. (110g)
|> <b>Size:</b> |< 2.32x1.14x1.96" (59x29x50mm)
|> <b>Torque:</b> |< 152 in oz @4.8v (11 kg cm)<br>183 in oz at 6.0v (13.2 kg cm)
|> <b>Speed:</b> |< .28 sec/60 @ 4.8v<br>.23 sec/60 @ 6.0V
|> <b>Manufacturer:</b> |< <a href=http://www.hitecrcd.com>Hitec</a>
When it comes to servos for large models, torque ratings seem to get the most attention, closely followed by price. Hitec has introduced a ¼ Scale Servo that offers not only a very acceptable torque rating, but a consistent centering servo for a price that rivals most ‘Standard Servo’s!
Albeit on the large size, this servo surprised this reviewer with its reliable centering ability. Add to this fact the quiet nature of the HS755HB, I feel this is one very good value. Yes, it weighs more and is larger than some of the $100+ servos, but when a giant scale plane requires 6 or more ‘strong’ servos, one can’t deny cost becomes a factor. I don’t know about you, but spending $600-$700 just for servos alone can dictate whether or not I can proceed along that level of the hobby.
@912086:Side-by-side with the competition...
@912087:if size and weight aren't crucial, then you may not need to pay the JR pricetag!
I compared the HS-755HB servo with my friend’s favorite JR 8611. The size difference was quickly apparent and the JR 8611 won in both the torque ratings as well as the speed needed to move the servo arm the proverbial 60 degrees. Of course the JR8611’s cost of $115 makes it possible to purchase almost four HS-755HB servos for one JR 8611! So, for models where the little larger size and little less torque aren't significant, I'd go for the HS755HBs!
*Special Features:
*Karbonite gear train;
*Dual Ball bearing;
*Water and Dust tight;
*Connector lead: 12” and color coordinated;
*5 Heavy Duty servo arms supplied;
*Molded rubber shock mounted grommets.
!Testing
@912088:Testing the centering...
@912089:...note the straw's accuracy, at 8" from the servo!
!!Centering
To test the servo, a quick solid wood frame was built and the servo was mounted with the supplied hardware. JR’s 1100 mAh 4.8-volt battery connected the servo to a HiTec Electron 6 Mini-receiver. The transmitter used was a JR XF421 as that was readily available to me at the moment.
The first test was to evaluate the centering quality of the servo. Using a large 8” soda straw attached to one of the supplied servo arms, 50 “trials” were attempted. Twenty-five trials were done by moving the aileron joystick full left and then permitted to return to neutral. Moving the transmitter stick to a full right position followed each of these movements. The transmitter stick was permitted to return to neutral while under the gentle pressure of my fingers.
By remaining sitting in the same position, the final resting position of the straw was carefully observed. Only one time did the straw not return to its initial position, and that was by less than 1/16”. Remember, this measurement was 8” from the servo arm!
Needless to say, I was impressed with this degree of accuracy.
!!Torque
The next test was to evaluate the torque rating. A wire pushrod was configured to hold some lead weights and connected to the servo 1” from the center. With the wood frame mounted vertically, the servo was asked to ‘lift’ various weights. The torque rating indicated 152 oz./inch. That’s a total of 9.5 POUNDS! To be honest, I never asked this servo to lift more than 128 ounces for two reasons: 1) the pan holding the weights couldn’t hold anymore and 2) I ran out of use-able weights.
Many times the servo would groan with pain as weight was lifted – a groan similar to the sound you get when you tighten the servo arm screw. But lifted it did! I didn’t notice any deterioration in the speed of the servo during these tests.
I’m sure the current draw escalated tremendously when this was done, but the necessary equipment needed to document this wasn’t available to me at that time.
!Conclusion
The servo hasn't yet had an opportunity to be flight-tested because the plane needed for this servo wasn’t available. However, in my humble opinion, this servo should do very well at the job it was intended for – guiding ¼ scale planes around the sky. I will not hesitate using it on my next ¼ scale project!
There are three types of people in this world...those who can count, and those who can't!!!!