Activity

Edward,Very interesting, never heard of the Z-pard but makes sense, however I can see how the center rod could be a major PITA and an additional potential cause for failure due to recovery elements becoming twisted.I had considered using Rouse…   Read more»

Wow – that is a lot of re-kitting of parts. Your containment seems to be well thought out. I know a few people who use surgical tubing with great success…maybe if you have redundant charges you can have one set…   Read more»

Ahh, I see now. I would think that containment would have been enough, but I do think that maybe the glass coupler bound. I’d be surprised if the charge were the problem, given your charge system.

The 2 gram charge was in a plastic centrifuge tube, ematch epoxied through the bottom with lots of electrical tape, the 2.5 gram charge was in a metal charge container that was part of the ebay setup – the BP…   Read more»

The green mark on the coupler was used for shear pin alignment. Maybe I’m not explaining it clearly but the motor casing was used as the coupler – It had about 4.5″ of casing in the upper body tube and…   Read more»

What method did you use to hold your charges?Edward

Was it only connected up to that mark on the coupler? If so, that does seem awfully short, and it lends credence to the idea that maybe the coupler bound.Warren: Doubled? 4+g in a 4″? I’m sure it separates quite…   Read more»

Adrian if you can somehow pull some data off of these that would be amazing:Doug downloaded some of the GPS data from the Garmin DC 20 system I was using and ballpark data from the GPS put the flight at…   Read more»

Just based on my experience with a similar size 4″ bird, while 2grams and 2.5 grams might reliably separate the airframe on the ground, it was not sufficiently reliable under flight dynamics. Twice it came in either partially deployed or…   Read more»

I found some more photos if that may help the discussion.Here’s a photo of the coupler I was talking about with the all-thread extension through the spacer. In the 2nd flight the spacer was not used and the coupler was…   Read more»

How short was the connection area after the coupler was shortened? The only theory I have that even remotely makes sense is that perhaps the coupler bound – glass and carbon tend to do that when only inserted a short…   Read more»

Is there a chance the Raven data is recoverable? The accel data might provide a clue about what happened when the charges went off.

Sean, one way to get around the joiner nut on the eyebolt is to use an eye nut http://www.mcmaster.com/#eye-nuts/=7dh21k You run that down tight onto a piece of all-thread.. You can torque them down incredibly tight, use lock nuts, and…   Read more»

Such a bummer 🙁 That was a beautiful rocket.My guess would be the shortened coupler section tweaked sometime and bound. I know John Bixler flew a Loki K350 with that setup and it was a bear getting that coupler to…   Read more»

A couple of additional notes after reviewing my post:- the data on the Rocksim drawing is not the actual CP/CG for this flight, this drawing was pulled from an old file.- An after thought as to what could have helped…   Read more»

So Joe had a motor that would work and the weather looked good on Sunday so I decided to give this L3 thing another shot. After discussion with my TAP I decided to trim the fiberglass coupler down so I…   Read more»

however….I apparently didn’t tighten it enough because this is what I recovered. You can see the fiberglass coupler in my hand. All thats missing is the fincan and motor casing. The eye bolt had come unscrewed from the coupler nut…   Read more»

I forgot…Edward also machined the propellant grains to very tight tolerances. I’m certain that the smooth thrust curve that the motor produced was the result of Edward machining the grains the way he did.

John, hats off to you and Mark for going out of your way to give credit where credit is due. I didn’t know Edward had contributed so much to the project — but I am not surprised. Edward is a…   Read more»

Edward gave me a VERY low price for Sorbitol, and how many times has he provided his hybrid motors complete with fuel for free trial uses?