This is a spin off from a thread titled "C6-0 meltdown" in Propulsion where the Krusnik Effect was mentioned along with a link to an old NAR report explaining the phenomenon.
From the last paragraph in the report:
"There is much more to be done in the
study of the Krushnic effect. Specifically,
there is a marked lack of accurate data on
the loss of thrust as a function of tube
diameter and length."
Posted by Handeman in C6-0 meltdown:
So with that in mind and for "scientific" reasons :wink: I decided to try and duplicate Handeman's event. I static tested an E9-4 (with the ejection charged removed) for a baseline and to see how well it compared to the published thrust curve. Later I removed the nozzle from the spent tube and cut the tube down to the same length as a D12-0. This was taped to a new E9-4 as described by Handeman and static tested. The results show a significant loss of thrust as Handeman noted. I must admit I was surprised by how much. :eyepop: Learned something today.
Steve G
From the last paragraph in the report:
"There is much more to be done in the
study of the Krushnic effect. Specifically,
there is a marked lack of accurate data on
the loss of thrust as a function of tube
diameter and length."
Posted by Handeman in C6-0 meltdown:
I don't know how common this is with the C6-0, but I've had several D12-0 motor "blow the nozzle" on me. Usually this works out with very little damage to the rocket, but that would depend on the pad design.
The last one I had was a CHAD staged D12-0 to a E9-6 in a D-Region Tomahawk. It was on a 1010 pad with an angled blast plate so no damage was done to the rocket, but I took quite a ribbing from fellow fliers. The D12-0 burned on the pad with no thrust and then lit the E9-6. Since that was burning through the D12-0 case, it had no thrust either. Six seconds after it was done burning, the ejection charge went off and got a big laugh from the crowd since the rocket hadn't moved the whole time. It did create a pretty impressive cloud of smoke though.
So with that in mind and for "scientific" reasons :wink: I decided to try and duplicate Handeman's event. I static tested an E9-4 (with the ejection charged removed) for a baseline and to see how well it compared to the published thrust curve. Later I removed the nozzle from the spent tube and cut the tube down to the same length as a D12-0. This was taped to a new E9-4 as described by Handeman and static tested. The results show a significant loss of thrust as Handeman noted. I must admit I was surprised by how much. :eyepop: Learned something today.
Steve G