A journey back into Brakes, Quietness, and Wind Shear.

This is the place to talk about everything airgun related including air rifles, air pistols, pellet guns, pcp airguns and more.
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LarryS
Posts: 189
Joined: Thu Nov 24, 2005 12:42 am

A journey back into Brakes, Quietness, and Wind Shear.

#1 Post by LarryS »

What to do on stormy days?..... You build another experimental brake!.

Just finished a second brake of 7 inches internal length. Three partition walls, evenly spaced are included which results in 4 chambers. The inner chamber partitions have 0.3955" diameter holes centered.

The end caps are interchangeable with 3 others of varying exit hole clearances around a .22 pellet or ball. Those clearances range from 0.030, 0.040, and 0.090 inch.

The sound is diminished proportionally to the size of the exit hole with the smallest hole(0.030 clearance), being the quietest. The object of the test is to find out how significan(if at all), wind shear might be to a pellet or ball exiting the orifice. That significance would be indicated by a displacement in grouping as the different size end caps are interchanged.

Problem is...... I must find a way to determine exactly where the ball or pellet is positioned when passing thru the cap orifice. If I can accurately center the ball or pellet, then the effect of the 3 different diameters can be measured.

To date I have not thought of a practicle way to do this because the air blast prevents putting anything over the hole etc. A rod I fashioned is not good enough to guarantee bore sighting perfectly.

ANY GOOD IDEAS OUT THERE?..... Must be "practicle with home tools".
-LarryS

Incidently- An air-tight variable sliding cylinder on the outside could progressively expose venting holes has occured to me to solved the outgassing which prevents pasting paper material over the hole.... but difficulties in finding the right diameter tubing prevents that approach. Maybe something to think about next time......
.......A variable sound brake! :lol:
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Exoce†
Posts: 173
Joined: Thu Sep 01, 2005 7:10 pm

#2 Post by Exoce† »

Sounds to me like a laser might fit your purpose. Even a cheap ten dollar laser pointer might do the job.
LarryS
Posts: 189
Joined: Thu Nov 24, 2005 12:42 am

#3 Post by LarryS »

Thanks Exocet+

I've a number of lasering devices that I use for telescope collimation. With difficulty I could adapt one to use in a mickey mouse manner.

The laser patern itself is never perfectly round due to construction. Even aligning the laser to bore center AND parallel to the bore axis alone would be difficult no matter which end is used.

It was a good thought tho' Exocet+!.......... LarryS
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