Had to take a couple of weeks off for family, this last week we have been working the local faire helping the Rainbow Girls troup sell hot buttered corn on a stick to a captured redneck crowd.
Last week, I received a package from Aerotech. They were at our local large launch earlier this year and Gary was showing off the new HEI system that they have made. I have been negotiating (begging) with Charles from RCS to test the system in our upper stage and provide feedback.
So.... drum roll..... here it is....
This is a floating head end closure which resembles the standard one, but, it has a glow plug initiator that screws into the top.
The initiator is available here
https://www.rocketmotorparts.com/Low_Cost_Head_End_Initiator/p1577809_16501656.aspx
The idea is that you fill the glowplug end of the initiator with black powder, and seal it. When the system gets current, the glowplug glows, setting off the BP which causes a flame front to shoot down the inside of the closure (think a narrow version of smoke well, matching the core size of a normal grain). This then starts the grains etc. etc.
Now - to my comments on this.
When I saw it at the sat on a table at the launch i thought it was a real neat idea. We pawed it and ooh'd and aaah'd etc.
Now I have it in my grubby hands, I am starting to see a problem or two.
1 - the Initiator is $30, and it is a one use item.
2 - the lead to plug into the top of the initiator is a semi hard to find milspec item which costs about $40-60 ( but as you see, I found that a JST lead pops straight onto those two posts... score! )
3 - and this is the absolute deal breaker - there is nowhere to screw in an eyebolt for recover retention for minimum diameter.
hmm... so, we won't be able to use this, but, I will be passing on a few ideas that I have gleaned from other posts on this forum.
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Update on the build.
Still working on HEI for the CTi load. If we use it in a snap ring case, with the hubcap system, then we 'should' be able to use our own HEI closure and tighten down the screws to get everything in place. Wont have upper smoke, but, will we see it at 50K??
Fixed the solder issues... still a slap on forehead moment.
Still working on getting myself happy enough with the motor / fincan retention on the upper stage. I have enough little worries at the back of my mind that I went and purchased the fully built Mongoose that was on the For Sale threads the other week. That has multiple CF tip to tip on the fins. Upper stage may change. We should still be able to MacGyver our electronics bay into it. Just thinking about that makes me happy. We will give that 'stage' the Barnards Star stickers...
https://www.rocketryforum.com/showt...-tip-to-tip-fin-can!!!!&highlight=mongoose+75
Lower stage interstage is being worked on, but all i am doing in that is making it so that there will be an external antenna on the AV bay. I am using 1/2 wave antennae that seem to be made of a 'memory metal'. I can wind the wire into a circle, hold it there for a minute, then let go and it springs back to fully extended. PERFECT!!!
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Looking forward to my first trip to the playa, and really looking forward to meeting some of you guys.
If this all turns explodey, then at least I have proved worthy of Team Numb :lol::smile: