Recoil Servo

[Ray Massa]

I am installing the recoil mechanism and two things are a bit different than the instructions.
The servo arm points downward in the pictorial, but the servo pulls back for recoil in the opposite direction. Just bench testing now, and wondering if positioning the servo arm 180 degrees will still clear the linkages.
Also, my servo mounting flanges have structural supports which will not allow the servo to mount flush underneath the bracket as shown in the pictorial unless I add some spacers. Mounting from the top may position the servo off-center from where it needs to be in line with the barrel of the gun.

Just wondering if anyone else has run into this and if the adjustment needed (mounting the servo underneath, and rotating the servo arm) will still function fine.

Thanks.

[Tom Miller]

Hi Ray,
You are correct. The recoil arm must be on top not underneath.
File off the plastic bits that keep the servo from mounting correctly.
Tom

[Ray Massa]

Hi Ray,
You are correct. The recoil arm must be on top not underneath.
File off the plastic bits that keep the servo from mounting correctly.
Tom

Well I thought about filing off the plastic bits but was afraid that would weaken the mounts too much for the torque that might be applied to the recoil. Probably not.
I think that is what I will have to do in order to keep the servo arm in line with the connecting rod.

thanks.

[Jerry Carducci]

Is it better or even possible to modify the mount to allow the strengthening ribs to remain? The mount being metal could stand a bit of
metal removal, slots or cuts to allow the servo to fit. Also if the recoil action has a lot of resistance I would believe something isn't right.

Haven't seen the exact implementation so I can't be certain but I always attempt to leave servos as they come.

Jerry

[Ray Massa]

Is it better or even possible to modify the mount to allow the strengthening ribs to remain? The mount being metal could stand a bit of
metal removal, slots or cuts to allow the servo to fit. Also if the recoil action has a lot of resistance I would believe something isn't right.

Haven't seen the exact implementation so I can't be certain but I always attempt to leave servos as they come.

Jerry

Jerry,

Attached is a pic of the servo and bracket. I suppose you could cut away part of the metal bracket, it is very robust. I think I will just mount the servo from the top. This will of course make the servo height in relation to the mechanism about 1/8" higher but it should not be a problem when I did a rough test fit. At least I will try that first. I would not say there is a lot of resistance on the gun barrel, but it is somewhat heavy. The barrel needs to be sanded a bit to slide nicely into the plastic sleeve.

Also, not related to the recoil, but on the machine gun assembly, you are supposed to Loctite in that assembly into front hull opening. If you do that, there will be no easy way to service that mechanism easily or at all because it is in a very tight space. If a linkage needs adjustment or a screw comes loose it may be a problem. I chose to not Loctite it. I was going to put some washers on the two screws on the inside bracket (that holds everything together) that screws into the large round aluminum piece. The washers would hit the side of the inside hull and It would then essentially compress the round piece against the tank hull, allowing it to be removed if necessary.

However, I found that so far, all I had to do was turn each screw counterclockwise a bit, and because they were ground down on the side, when rotated they hit the side of the hull and locked the assembly in place. If it ever loosens, I will just go with the washers method instead.

One more thing on the LED's. They will burn out as Tom Miller stated if no current limiting resistor is used. When I first was bench testing, they worked fine for many on/off times. I thought maybe Tom was just unlucky. But, to be safe I was going to put a resistor in line anyway, so I turned on the LEDs to get a current reading with my meter and they essentially went very dim and then shut down. I thought, OK so I will replace them. Well, after a couple minutes, a put a resistor (480 ohms I think), in line, turned it back on and they worked again! And I left them on for a long time to see if they held up and they did. So a warning to all, put a resistor in line before you turn them on.

-Ray