I would do a trade to see what if you just put the added insulation around
the outside would it be enough to do an end burner? It would be simpler
with higher packing fraction.
On Mon, Jul 4, 2016 at 1:01 PM, Ed LeBouthillier <codemonky@xxxxxxxxxxxxx>
wrote:
I was discussing the microlaunchers idea with a coworker and he asked if I
had considered using solids. I said yes but I outlined some of the problems
I thought that they had in this application (e.g. high acceleration rates).
He said if only you could change the geometry of solid motors, maybe
spiral the propellants, then you might be able to get behaviors more
conducive to small rockets.
I thought that was a good idea and so I told him that I would look into
the “Zepeda Ho Ho” solid rocket grain.
Interestingly, I found a patent from 1967 which discusses the technique:
Spiral burning propellant charge
https://www.google.com/patents/US3496870
It’s an interesting idea.
I’ve toyed around with initial design work on the approach and it seems to
offer some advantages (although there is an obvious cost of increased inert
weight due to insulation).
It does seem to be able to get just about whatever burn duration (and thus
thrust profile) desired but without the same insulation requirements that
an end-burner would require.
For small launchers (i.e. microlaunchers), it seems to open up the
possibility of using solid propellants.
Have any of you heard about or thought about this approach before?
Do you see any major problems with its application to smaller rockets
(other than the increased inert weight of the insulation)?