segunda-feira, 5 de março de 2012

GFC Tornado Motors

GFC Tornado Motors:

The motors have been developed in two versions, High Torque and High Speed, both of them are available in long (V2 gear boxes) and short (V3 gearboxes and others) shaft configuration.
GFC sent us two long shaft motors and a full set of Guarder springs, from SP90 to SP150, to test the performances of the motor in all these configurations.

 Test hardware configuration:
To test these products we have assembled and optimized a gearbox, which is capable of withstanding stresses at high frequency, as occurs in high-speed configurations, that high intensity, using springs well above the limit of Italian 1J.
So we assembled a 2nd generation low cost gearbox branded SB and equipped with full steel 6mm bushings. The gears used are: Golden Bow spur gear, DBoys sector gear and a Royal bevel gear. How you can see from the photos the sector gear is darker then the other two because it has been tempered.
The pneumatic system has been assembled with a Royal transparent blue piston with 7 metal teeth, the piston head is of an unknown brand with a better Oring to have a perfect seal between cilinder and piston.
The cilinder is a carbon fiber DTC brand without holes. Cilinder head and nozzle are Dboys branded. 
The choice of using low cost components has been used to prove the quality of these spare parts.
Last but not least we lube the gears with molybdenum disulfide grease, the other components (piston and tappet plate guides, cilinder interiors) has been used the High Speed DTC Grease Mixture.

 Tests have been made starting from the softer spring Guarder SP90, we tested both motors with a LiPo 7.4V 3000mAh 35C and a 11.1V 1600mAh 25C batteries. After every tests the spring has been upgraded until the last, SP150.
To measure the rate of fire has been used a freeware audio editing software and to measure the absorbed current has been used a Turningy 100A amperometer designed for the dynamic modellers.

Let's see the results obtained in the following graphs:

 Let's see the results obtained in the following graphs:
At the end of the trials we deassemled the gearbox to check the wear conditions but all the components were as new except for the piston, shown in the photo below:

 As we can see the wear on the first tooth is largely due to to a wrong angle of engagement with the first tooth of the sector gear. The second tooth, which has not been intentionally removed in order to maintain intact the original characteristics of the piston,  presents a slight wear but does not affect in any way the proper functioning of the component.

With the 7.4V battery it's easy to see that the rate of fire is really similar for the two motors. With the SP100 the difference it's quite big. This difference may be because of the adaptation of brushes to the motor commutator . In this test the motors do not have been run in order to allow a perfect adaptation of the brushes to the switch to better re-create a situation of actual use.
Increasing the hardness of the springs is possible to see how the High Torque version has a more stable graph instead of the High Speed one that suffered more the spring change. At last with the SP150 spring the high speed version had not enough torque to compress all the spring, the other one instead had not any problem to run also the hardest spring.

 With the 11.1V battery the measures had been better than the previous ones. As you can see from the graph the two motor have a really similar behaviour, the high torque one has a more stable response to the spring changes.
In the end, the High Torque motor has a less current absorption than the High Speed brother, especially with the 11.1V battery.

These motors have good performances, in particular the high-speed model has positively affected both for the torque, which has allowed to reach the 26bb / s with the SP150, also for the top speed reached with the SP90 and equal to 33.5 bb / s, an excellent result considering that the gears used in this test have a standard reduction ratio.
The high torque model performances are not so exciting because we expected a more flat graph curve useful to obtain a stable rate of fire with all the spring configurations.

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