[AR] Re: Antares Lost On Liftoff
- From: Nate Downes <downix2k@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Thu, 27 Nov 2014 09:05:05 -0800
I had thought the hydraulics had been upgraded to electronics by Aerojet
some years back.
On Nov 27, 2014 4:34 AM, "Bill Claybaugh" <wclaybaugh2@xxxxxxxxxx> wrote:
> Then you are no doubt very familiar with the hydraulic balancing system;
> the function of which you do not apparently fully understand.
>
> Bill
>
> Sent from my iPhone
>
> On Nov 26, 2014, at 18:51, Nate Downes <downix2k@xxxxxxxxx> wrote:
>
> I'm quite familiar with the NK-33 drawings and the fuel flow, and I'm in
> agreement with Peter and John. The speed of the turbine combined with the
> method of manufacture would make a soft failure far less likely. Not
> impossible of course, but less probable. I could come up with some
> scenarios which could cause it, but they would be easier to recognize by
> sensor feedback.
>
> On Wed, Nov 26, 2014 at 2:48 PM, Bill Claybaugh <wclaybaugh2@xxxxxxxxxx>
> wrote:
>
>> Not bad....
>>
>> A detailed look at the NK-33 drawings would change your mind about about
>> the probability of sudden failure--soft failure is inherent--but otherwise
>> not bad at all.
>>
>> Bill
>>
>> Sent from my iPhone
>>
>> On Nov 26, 2014, at 17:07, "" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted
>> sender "JMKrell@xxxxxxx" for DMARC) wrote:
>>
>> Peter,
>>
>> I agree with you on the oxygen rich preburner/turbine duct failure. LOX
>> pump failures produce sudden engine failures. The one AJ26 experienced a
>> progressive failure over ~970 ms. Starting with the change in O:F ratio,
>> the flame color progressed from slight yellow to bright yellow over the
>> next ~700 ms. In the next three frames a flame extends horizontal away from
>> the vehicle and vertical along the tanks from the propulsion
>> section. Approx 180 ms later there is a bright flash at the base of the
>> vehicle and all propulsion ends. This should be the LOX pump and turbine
>> failing. High velocity debris is then visible leaving the vehicle.
>>
>> If it was strictly a LOX pump failure, I would expect a sudden end to
>> propulsion and debris being observed earlier in the failure. If the
>> preburner duct burned through at the turbine exhaust, it might be difficult
>> to separate a LOX pump failure from a duct failure. If they have pump shaft
>> RPM data the failure sequence should be observable.
>>
>> John Krell
>>
>> In a message dated 11/26/2014 9:22:48 A.M. Pacific Standard Time,
>> zenadsl6186@xxxxxxxxx writes:
>>
>> On 26/11/14 14:42, Bill Claybaugh wrote:
>> > The lox turbopump failed.
>>
>>
>> Hi Bill,
>>
>> Is that a it's-been-determined-that's-what-happened, or a
>> I-think-that's-what-happened?
>>
>>
>> Brightness in the plume could be because of a LOX pump failure, with
>> lesser amounts of LOX (and perhaps more kero) flowing, but I'd have
>> thought that the size of the plume would not have grown as much as it
>> appeared to.
>>
>> If the LOX pump to preburner duct broke, rather than the pump itself,
>> then the extra LOX would have brightened the plume and made it larger -
>> the pre-failure existing nozzle exhaust would be fuel-rich, and adding
>> extra LOX to it would have had the observed effect.
>>
>> Same would be observed if the preburner/turbine to chamber duct,
>> carrying LOX-rich preburner exhaust, broke. My 2c is on that one, but
>> someone may know better.
>>
>> -- Peter Fairbrother
>>
>>
>
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