Bill,
I haven't tried titanium for a motor casing. Other than the cost, it's
more difficult to machine. Plus, titanium is not allowed under Tripoli
Research which is how I test & launch most of my motors. I tried to find a
Ti alloy with both strength and non-frangible characteristics. The
manufacturer's data and published sources weren't clear. Difficult to
determine without (expensive) destructive testing.
-John DeMar
Las Cruces, NM
On Tue, Jan 11, 2022 at 11:11 AM William Claybaugh <wclaybaugh2@xxxxxxxxx>
wrote:
John:
Have you or anyone you know ever looked at Titanium tubing? I’m finding
that 0.050” wall 6” outside diameter tube can be had for around $700 per
60” length vs. about $240 for an aluminum tube at 0.125” wall.
That would come in at about two-thirds the weight of the aluminum tube,
saving three pounds or about 10% of the current dry mass of my 6” motor.
It would require going to button head fasteners rather than countersunk so
drag would go up some but that weight savings appears to be worth an about
10% altitude gain and thus might be worth the extra $500 per flight.
Bill
On Tue, Jan 11, 2022 at 9:17 AM John DeMar <jsdemar@xxxxxxxxx> wrote:
The phenolic looks interesting as a motor casing. They spec axial
tensile strength but not radial. 60% the weight of aluminum but only 17%
the tensile strength. There goes the weight advantage unless one adds a
carbon fiber overwrap. And hydrostatic tests it. Still, there's the issue
of attaching closures to the tubing... appropriate adhesive, plus pinning,
plus insulation.
-John DeMar
Las Cruces, NM
On Tue, Jan 11, 2022 at 8:16 AM James Fackert <jimfackert@xxxxxxxxx>
wrote:
maybe of interest for airframes and solid motor builders-
championfiberglass.com
has glass epoxy and phenolic epoxy conduit in 3/3" to 8" sizes, three
wall thicknesses, 10 foot lengths
lots of coupling anf fitting options
even split clamp over repair/reinforcement tubes.
should be reasonable prices since its a commercial product.
