I've taken the week off from the day job to be Unreasonable. I finished the last of the machining on the new stainless motor, I picked up the chamber liner from flame spray and now all the parts are at the welder. I received all the turned stainless parts today, so I have spares.
To finish my earlier discussion about sending parts out I talked to the vendor and he actually did not have any scrap. All his problems or issues were found in dry runing the programs on his CAM software, so no scrap generated.
The Blue Ball software is ready to test again, we may do so this weekend.
I've still got to get the video working correctly.
51 days and 7 testing weekends to go.....
8 comments:
i want to thank you for posting so much of your progress notes so frequently. i used to read armadillo but they have gone into deep cover i guess and have not updated in 4 months.
i am not a rocket techie, so may i ask a newbie question? why are you going with stainless now and not earlier? is it because when you do the fab in aluminum you can get it done faster and test stuff that is not necessarily heat critical, and only go to stainless when you have all the little nits worked out? does the change to stainless affect assumptions of how the motor will perform with regard to heat expansion etc vs. aluminum?
I'll have a shot at the answer;
The blue ball is a stainless engine construction but it does not have regenerative cooling as it is a mono prop engine only.
The silver ball was alloy initially as the extra machine work necessary for the regenerative cooling is far easier process with aluminium alloy. The extra work is necessary as this engine is a dual prop engine using kero.
The alloy should have been fine though the margin for error and its ability to deal with odd heat spots is far less than what the stainless can deal with. Unfortunately for Paul this proved to be an issue recently hence the new and improved engine is stainless where some of the machine work has been farmed out instead of it being totally in house.
The design is roughly the same though internal injector design has been upgraded. I would think the slight extra weight would not be an issue. The fact the engine will most likely handle the multiple longer 180-190 sec flights is the key design criteria as there is no time left this year to redesign if it does not go well.
I also agree with you then it is truly great that Paul keeps posting. I know commercial interests are now in play for Armadillo which is great for them its just we the peanut gallery still want our fix. Hard balance. My gut tells me in the long term having public support will do a company well in the future endeavours.
Subscribe to the arocket list if you want to see far more regular tidbits of what's going on at Armadillo, Masten, etc.
The switch to stainless has more to do with the catalyst pack than anything else.
You want the cat pack hot, but not too hot. So it is in uncool-ed stainless, the rest of the motor needs to be regen cooled, and from a practical matter I don't know how to make a joint between cooled aluminum and stainless hotter than the softening temp of aluminum, hence all stainless.
Thanks Paul for the clarification.
Joining ARocket has been a good source of information in general and for Masten and Armadillos activities - I am personally glad of it. Only I do question; arocket list is for Amateur rockery - when do you classify those organisations are no longer amateur pursuits?
how do i subscribe to arocket list, please give mailing list url or sometihng?
http://exrocketry.net/mailman/listinfo/arocket
http://cosmiclog.msnbc.msn.com/archive/2009/09/11/2064885.aspx
I assume you have seen this.
Andy
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