Mercury also used double base propellant device actuation. I think we may have
learned a bit since then.
Anthony
Sent from my iPhone
On Aug 28, 2016, at 10:02 PM, John Dom <johndom@xxxxxxxxx> wrote:
Silver plated stainless screens and 90 %: the Mercury capsules RCS had
trouble with it. The screens were deformed by the decomposition temperature,
became brittle and pulverized in part. That is why in the later cat bed
versions, they used platinum screens in part, which are better resistant to
the high gas stream temperature and oxygen presence. I think pure silver
screens melt in 90 % HTP. Depending on run time.
jd
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On ;
Behalf Of Paul Breed
Sent: maandag 29 augustus 2016 1:59
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: "Direct" Hydrogen Peroxide engines
Realize that dragsters are never running more than 15 seconds....
I've never fired a peroxide motor for less than 45 seconds unless it was an
abort...
I think the thermal mass of the screens may reduce stripping in short runs...
Paul
On Sun, Aug 28, 2016 at 4:10 PM, William Claybaugh <wclaybaugh2@xxxxxxxxx>
wrote:
So dragsters all used 85%? Interesting.
And you have consistently seen loss of silver using 90%%? But Lloyd has not
seen this problem?
Is everyone using samarium oxide overcoat? Processed identically? I ask
because getting it on correctly appears to involve a good deal of art based
on my working with the fellow who did it for my motor.
Bill
Sent from my Commodore 64
On Aug 28, 2016, at 4:55 PM, qbert@xxxxxxxxxxxxxxx wrote:
At 02:17 PM 8/28/2016, you wrote:
So I'm confused: peroxide motors for dragsters tend to need refurbishment
every decade or so...which suggests the silver is not coming off every runÂ
and the samarium oxide coating is working.
Why are folks here consistently reporting a problem?
Most of them had access to lab grade 85% peroxide with which there is little
problem but most of that has gone away just like the era of the peroxide
dragsters. Try getting lab grade now. And anything using >90% peroxide will
strip their screens sooner or later, even a 63 run on 87% stripped our
screens back in 2007, we started to see the thrust fall of at about 45seconds.
On another note, Anyone want a 9lb peroxide turbine? This is from the same
guy who came up with the 1L of 50%/193g of sugar formula for a steam turbine.
I wish I'd seen this back in 2004 when I was playing with the SS motor.
https://www.youtube.com/watch?v=kpg4g47ssFY
Robert
Bill
On Sunday, August 28, 2016, David Weinshenker <daze39@xxxxxxxxxxxxx> wrote:
On 08/28/2016 12:31 PM, Paul Breed wrote:
I don't think this thermal decomposition will work with 85 or 90%, I
think it would have to be 98%.
We've seen the thermal decomposition thing apparently work,
in our misadventures with phosphate-contaminated "90%" peroxide:
with a freshly prepared catalyst, the motor would start and
run apparently well as long as it was at operating temperature,
but once stopped and cooled down it wouldn't start again.
So it seems like once the catalyst surface is quite hot,
there will be decomposition even if it has been chemically
"poisoned".
So I'm thinking: start with a motor stacked with silver-plated
nickel or stainless screens, give it one good long run with
high-concentration peroxide, then examine the screens to see
where the silver survived and where it was hot enough to strip
off... then replace the screens downstream of there with a
more heat-resistant type.
-dave w
