Thanks John for your reply. Hmm you may have a point about risk to others.
Regards
Robert

Hi, I must confess I have thought of using BB system myself to fire plastic pellets, as my son is into airsoft and he has one or two airsoft innards e.g. gear boxes and compression cylinders which are available to me for a slight price (I bet). Problem is though these firing mechanisms from airsoft guns can fire a pellet between 300 and 350 fps (feet per second) which can be lethal if you hit someone at the side of the lake. My son just informed me it can be a criminal office if the internals of an airsoft gun have been used in a model. Be very cautious and look into it. I am sure there are places who do mock battles and use similar systems to this. You would need to source these people and find out the rules and regulations from them before proceeding.

Just re-read your posting and realise you are going to use tank internals - I am not sure what the system is there, but even with that, its wise to check it out first before firing in a public place.

john

Thanks John for your excellent response. I have also been toying with using a BB gun mechanism for a tank to fire bb bullets. Do you think this is feasible?

In my USS KIDD I use two of these to control the
forward turrets, easy to set up with either a standard sero, or micro servo if space is a problem, not figured out how to elevate yet.
https://action-electronics.co.uk/pdfs/P96.pdf
cheers Peter😊

hi there

here is a possible idea for you - this is the system I used for the guns on HMS Exeter which is of a scale of 1:96 - I used a miniature servo for elevation; also a servo which is able to drive 180 degrees for the main rotation of the gun.

The servo is mounted underneath and where you locate the arm on the servo, I made a tube which goes all the way through the barbet into the base of the gun, this is the connection which rotates the gun.

The cable from the miniature servo which elevates the barrels run inside the tube and comes out through a small hole at the base of it.


I also use an electronic servo slower and stretcher from Forge Electronics to slow the movement of the guns down to a scale speed. The only problem I had, was, I found when elevating the barrels up and down - they tended to be slightly jerky in movement and it took me a while to work out how to dampen this - and all things equal - the simplest solution came to rest - make a rubber wedge which fits between the side of the barrel mounting and the side of the casing, causing a little bit of resistance.

Hope this is of some help.
http://www.forge-electronics.co.uk/index.php/boats/servo-controller


John

Hi Hillro,
On my HMS Cottesmore I have modified a standard servo to rotate continuously and fitted limit switches.
So now I can get approximately 290 degree of rotational movement.
How ever I have not made the gun elevate, but I should of attached another servo to the rotating base to do this.