Victorian Air Cane Restomod

[Unframed Dave]

Just to add, the OP is not based in the UK.

Excellent thread.

Dave

[AC all day]

I am friends on FB with a guy who plays with Giffards, "there built for shooting not wall hangers" again not based in the UK but once it's been re sealed there good to go and still very impressive....

[fullmetaljacket]

Thanks gents!

Just to add, the OP is not based in the UK.

Yes I should have specified.

"there built for shooting not wall hangers"

I have to say that if it was complete with pump, accessories and case I would have been more reticent to dismantle and shoot it, but as it is this example is perfect to tinker with.

[fullmetaljacket]

Some progress, I gave the balanced valve a go and was able to raise firing pressure to 1100 psi.

Video of some initial testing with this setup

Best velocity recorded was 774 fps for 59.3 ft lbs, around 50% more than the maximum for the conventional valve.

I was a little conservative with the diameter of the balanced portion, I was worried that if it was too close to the seat then it might have problems sealing.

In that regard I've probably erred too much on the side of caution with 7mm, and can afford to go a little higher...

More to follow, I will post more details of the valve once I've optimized it further.

[Shed tuner]

awesome thread.. very interesting on the valve/lock mech too.

[fullmetaljacket]

Thanks!

Some balanced valve development:



Balanced valve V1 and housing compared to the improved poppet and original housing.

Note the groove at the head of the valve to allow air to vent into the balanced portion.

The head diameter is also reduced to 6mm from 8mm for better flow.



Balanced valve V2 with a larger bore balanced portion to decrease the seating bias and allow operation at even higher pressure.

Diameter is increased from 7mm to 9mm and the housing is bored out accordingly.

Pumped it up to 1800 psi and shot it over the chrono.

The display showed 520 feet per second but I suspect this is erroneous as the lead ball went further into the wooden backstop than previous shots. The muzzle was probably too close to the first sensor on the chrono.

Loaded up a second shot and got an almighty whoosh, and this:



That works out at 84.2 ft lbs

The chamber was completely empty however, and subsequent evaluation revealed the reason:



It turns out that allowing the valve to bottom out and a relatively weak valve spring might not be the best ideas at this end of the performance spectrum...

I think a minor redesign will solve the issue, watch this space

[draitzer]

That is really slick, a deer-hunting cane! There is also the possibility to adjust the opening / lift of the valve, maybe by a screw on the metal head to change the clearance from striker to valve.

Don R.