PPRuNe Forums - View Single Post - One down in the Riverland
View Single Post
Old 18th Jan 2017, 12:49
  #20 (permalink)  
youngmic
 
Join Date: Dec 2005
Location: Perth
Posts: 176
Likes: 0
Received 0 Likes on 0 Posts
Good news the pilot survived the wire strike.

Aerial bird control has been going on for some time in fact it pre-dates the era of over the top PC and OH&S way back to a time when inventiveness was applauded......circa late 80's early nineties.

What apparently seems to work rather well in this arena is a good slow-ish speed ultralight with a surplus of climb power. Then mount a stripped down forward firing shotgun on a recoil absorbing grease lubricated mounting system, (alloy tube with glued in pvc insert lining and a grease nipple). Of course a remote triggering device will be needed obviously and a piece of string tied around the trigger and then to a convenient part of the airframe works quite well. This system will give repeatable accuracy and good service life

The best place to mount the shotgun is between the rudder pedals just outside and below the prop disc. Due to the distance between the low mounted gun and your eye sight line a sighting system will need to be employed. History shows that a spring tensioned taught piece of string attached vertically from below the overhead engine and down through the nose pod out in front of the windscreen is a simple forward sight. A movable knot along the string completing an effective and adjustable forward bead sight.

All that is now needed is the rear sight and nothing more than a fine line texta set of cross hairs, as you might guess drawn on the windscreen does the job nicely, this is cheap and effective. Undoubtedly the astute reader will wonder how distance to target can be assessed so as to determine when the angle between the bore sight line and the eye sight line coincide with the #5 shot trajectory and the effective kill range of approximately 40m. Here it is important to know the size of the target, typically a crows wingspan which is not hard to determine with the aid of a dead crow or compliant live one.

If one closes one eye whilst seated in the cockpit (on the ground) and aligning the forward bead sight with the cross hairs it becomes a simple exercise of marking (with the texta) two little vertical marks on the horizontal line of the cross hair that equates to the crows wingspan when viewed from the cockpit through the cross hairs to the forward sight and on and out to a stretched out dead crow or living as the case may be. For conformation and fine tuning a crow silhouette on an old car bonnet placed at 40m is indispensable.

All this is well and good you may ask but how would one reload such a contraption in the air whilst maneuvering at low level?. It is here that a little elemental physics and a length of thick spear gun elastic come into play. If one were to attach the spear gun rubber (or rubber sealing ring from a 12" pvc pipe) to a pair of small welded on rams horns on the stripped down breach assembly all one has to do is press the lever that breaks the breach and the elastic rubber breaks the gun leaving the wind pressure to blow the spent cartridge out of the barrel and down through the opening in the floor.

A cunning installation would of course use the same elastic chord as the primary aft recoil absorbing method and a rubber bumper or old tractor valve spring slid over the barrel as the forward return absorber which works very well.

It is said that if a system such as this is employed early enough in the season before the birds establish the orchard as a food source and an alternative food source away from the orchard is established were the birds are not harassed the battle is won with minimal killing.

However it just leaves one last question on how to actually go about doing it...but that is another story.

Of course it is only story and any resemblance to the above story and events in history is mere coincidence.

Last edited by youngmic; 18th Jan 2017 at 13:08.
youngmic is offline