Tegheim - Home made 4 rotor Wolvo 142

[Tegheim]

It might be worse, but we have an idea.
We try this way, and if it's not working. Let's do it again

[rgould]

As a fellow machinist and race piston engine builder why make a steel rotor when you can buy iron ones i would think if you are going to go this route use Titanium and save the weight ( half the weight of steel and all most the same strength ) or Is it to say it can be done.

[Mazdabater]

The titanium would probably crack, it's too brittle.

[rgould]

well seeing how titanium is used as compressor blades in turbine engines.
The SR71 Blackbird is 95%+ titanium seeing any where from 500 to 3000+ degrees F at mach 3+
It's used as intake and exhaust valves in all forms of race engines, head studs for Top fuel engines at 8000 hp.
I question brittle. Figuring out the expansion rate for proper clearances at operating temps mint be a little tough.
Machining it's a bitch and aircraft quality billet is pricey.

[Mazdabater]

Given how much I see it crack on aircraft firewalls, I wouldn't trust the apex seal groves, that's just me though

[WankelsRevenge]

Plus, isnt titanium insanely expensive when compared to steel/iron?

[rgould]

Given how much I see it crack on aircraft firewalls

I would say that an apple to orange comparison of a sheet metal fire wall of 0 too thin sheet titanium vs a copy thickness of a cast rotor thickness ( most people try to run titanium as thin as possible instead of the same size as the original Steel part trying to maximize the weight saving)

As an A&P in the US, aircraft firewall in the US is stainless steel per FAA. reg. non military

Plus, isn't titanium insanely expensive when compared to steel/iron?

which is why I asked why make a steel rotor when you can buy iron ones I would think if you are going to go this route use Titanium and save the weight ( half the weight of steel and all most the same strength ) or Is it to say it can be done.

But it was just a question to see the thinking behind the route taken.

[Mazdabater]

Yep, its a bitch to work with. And if you question brittle get some and try and bend it, needs a much bigger bend radius then stainless. It has it's applications no doubt. Studs and valves are a much different application to an actual rotor.

[Tegheim]

The main idea was to SAVE money doing them myself and get the other forefits along with it.
A used Rotor today are about 200USD, the material-cost only for a new one in billet-steel is about 100-110USD. And the work I do by my self.

[rgould]

I can understand that thinking.

With over 20 years of machining a lot of it for high end race teams and programs I tend to not look at the dollar amount but what is the advantage gained from something. I have been told buy people that know me that my out look is skued from the work that I have been involved with over the years.


Hope it works out
Good Luck

[Tegheim]

We have done awsome progress this weekend. But we will not show it yet

[Whizbang]

im pretty sure turbine blades are a titanium alloy, specifically titanium scandium

[My5ABaby]

Originally Posted by Tegheim

We have done awsome progress this weekend. But we will not show it yet

[Herblenny]

I just ran into this thread...

First, welcome to RCC!

Second, I will be following this thread

[infernosg]

Originally Posted by Gravity Fed

im pretty sure turbine blades are a titanium alloy, specifically titanium scandium

Compressor components are made from titanium-based alloys. I know Ti 6-4 is used quite a bit in blades, disks, etc.

What's a typical rotary EGT? I'm thinking all the titanium alloys I'm familiar with would not stand up to rotary combustion chamber temperatures and gases for very long. Titanium is poor in high-temperature oxidation and corrosion. Almost all modern-day turbine components (at least in the industry I work) are nickel-based. Inconels, Hastelloy, Waspalloy and other materials I can't name.