Erik Bengtsson
Bobby,
The rockets I have built (-most of them are small rotor tip rockets),
I have not compressed much at all. I believe one only need to compress
enough to make the catpack fill out the whole cross section area
without any void areas between the catpack screens and the chamber
walls. That means one need to compress enough to prevent channeling
between the cat pack screens perepheri and the chamber walls. Any more
compressing than that just gives increased flow resistence/increased
pressure drop and no more benifit.
Also I believe one should have some compression created by pushing with
the flange bolts on the screens all the time during operation -not only
at one time before assembling the cat pack and than loosening the
compression at assembling. At least the silver plated stainless steel
screens I use are quite elastic (behaving like "springs") They again
expand as soon as loosening the compression. That is why they should be
assembled with a compression during operation. The pure solid silver
screens are much more soft and plastic in behavior.
The rotor tip rockets must have a small diameter to fit into the rotor
blade profile. Therefore the cross section load is high and the
pressure drop becomes high. If there is no such restrictions for the
diameter I believe one should go for a load of around 0.01 kg
H2o2/minute per square mm of the cross section area. Translated to a
rocketbelt that would mean 3.5 inch diameter and a pressure drop of
about 4 bars from the inlet to the outlet of the catpack, but I think 3
inch will be fine also. I see not much reason to go for a lower
diameter than 3 inch though.
I wish I could build rockets all the time, but unfortunately I have to
work for a living. Right now I am responsible for starting up this H2O2
plant in Pakistan:
www.desconoxychem.com.My son Gunnar is running our
rocket grade H2O2 plant in Sweden in the mean time. Last year I took
part in building a H2O2 plant in Bangladesh. When I come back to Sweden
I will start build rockets again!
Erik
