During the webcast today, one of the SpaceX presenters who works on the grid fins manufacturing, stated that they are made of aluminum.
So the expensive upgrade material of choice would be what, stainless steel?
For proper cost plus contracting style performance-at-any-price specs the goto material is BerylliumHalf the mass, operating temperature up to 600c+ and only 400x more expensive than Aluminum. You'd be a fool to use anything else.
Quote from: john smith 19 on 06/15/2016 10:15 pmFor proper cost plus contracting style performance-at-any-price specs the goto material is BerylliumHalf the mass, operating temperature up to 600c+ and only 400x more expensive than Aluminum. You'd be a fool to use anything else. Sounds like Sucker Bait!
An excellent material in many ways apart from it's cost, brittleness and ability to kill people in various horrible ways.
QuoteAn excellent material in many ways apart from it's cost, brittleness and ability to kill people in various horrible ways.For a while back in the '80's, the Air Force was looking at using beryllium powder instead of aluminum powder as a way to up the Isp of solid propellants being developed for the Strategic Defense Initiative (SDI) program, aka "Star Wars." But the toxicity of beryllium oxide in the propellant exhaust made it a pretty bad idea that was fortunately never implemented.
Quote from: Kabloona on 06/16/2016 12:50 amQuoteAn excellent material in many ways apart from it's cost, brittleness and ability to kill people in various horrible ways.For a while back in the '80's, the Air Force was looking at using beryllium powder instead of aluminum powder as a way to up the Isp of solid propellants being developed for the Strategic Defense Initiative (SDI) program, aka "Star Wars." But the toxicity of beryllium oxide in the propellant exhaust made it a pretty bad idea that was fortunately never implemented.A former coworker of mine has been suffering for years from beryllium disease. Her exposure consisted of working in a building that had years before been used for machining beryllium metal. I've seen how much she's suffered from it, and her survival is very much a day-to-day thing. It's definitely nothing to be taken lightly.
Quote from: llanitedave on 06/16/2016 01:21 amQuote from: Kabloona on 06/16/2016 12:50 amQuoteAn excellent material in many ways apart from it's cost, brittleness and ability to kill people in various horrible ways.For a while back in the '80's, the Air Force was looking at using beryllium powder instead of aluminum powder as a way to up the Isp of solid propellants being developed for the Strategic Defense Initiative (SDI) program, aka "Star Wars." But the toxicity of beryllium oxide in the propellant exhaust made it a pretty bad idea that was fortunately never implemented.A former coworker of mine has been suffering for years from beryllium disease. Her exposure consisted of working in a building that had years before been used for machining beryllium metal. I've seen how much she's suffered from it, and her survival is very much a day-to-day thing. It's definitely nothing to be taken lightly.Wow, what a shame. I knew the oxide was toxic but I didn't know the raw metal was too.
Wow, what a shame. I knew the oxide was toxic but I didn't know the raw metal was too.
Quote from: Kabloona on 06/16/2016 01:34 amWow, what a shame. I knew the oxide was toxic but I didn't know the raw metal was too.Well, if you take a grid of the naked metal, heat it up to redhot temperatures and stick it out in a supersonic oxygen-filled airstream, you are likely to get quite a bit of oxide..Besides, isn't the metal a bit on the weak side?
Half the mass, operating temperature up to 600c+ and only 400x more expensive than Aluminum.
I'm probably not allowed to tell you how much the beryllium mirror in the Exoatmospheric Kill Vehicle's telescope costs.
QuoteI'm probably not allowed to tell you how much the beryllium mirror in the Exoatmospheric Kill Vehicle's telescope costs.Or how many people got poisoned building it. Hopefully none.
John smith 19 wasn't really serious about using beryllium anyway. Let's get back to reality...
Titanium is the logical upgrade choice as Robotbeat says, if they choose to go that route. IMO it comes down to a cost tradeoff, expensive but almost infinitely reusable titanium, vs cheaper but finitely reusable aluminum.
SpaceX has shown their focus on cost optimization rather than performance optimization, so life-cycle cost will probably be their discriminator.
The shape those grid fins were in suggests they are far from infinitely reusable.
The results of the wind tunnel test indicate that the aerodynamic characteristics of grid fin depend much more on the area of each and total grid cell than that of lifting surface. In other words, the triangle pattern could be better choice for the grid fin because of higher structural strength compared to a square and a hexagonal pattern. That makes it possible to have a thinner web, which reduces the drag of the grid fin.
But when you consider how much less dense aluminum is than titanium, it seems like it'd be very difficult to close the case for titanium.
Titanium is 66% heavier than aluminium (per unit volume) but has higher yield strength and 66% higher young modulus.This means thinner sections and same mass, with better resistance to temperatures over 120-140 C°.That's why Kelly Johnson used it for the SR-71.
Or how many people got poisoned building it. Hopefully none.