my stream wiggles

I built a smaller jet using 4" dia pvc. The nozzel hole is .375" dia. The stream comes out very clear and looks laminar but the stream starts to wiggle about 4' away. Is that because the 4" pvc is too small? Would a 6" dia be better? should I make a new nozzel with a smaller hole? I'm not looking for a lot of distance maybe 60" long by 48" high. I have built a 8" dia jet but that is just to big for my exhibit.
Glenn

gwoodward wrote:I built a smaller jet using 4" dia pvc. The nozzel hole is .375" dia. The stream comes out very clear and looks laminar but the stream starts to wiggle about 4' away. Is that because the 4" pvc is too small? Would a 6" dia be better? should I make a new nozzel with a smaller hole? I'm not looking for a lot of distance maybe 60" long by 48" high. I have built a 8" dia jet but that is just to big for my exhibit.
Glenn

hi Glenn,
4" dia pipe is too small to produce long range laminar flow. So the breaking/wiggling/distortion of laminar stream at 4' is not new for such small dia pipe. Better is to look at bigger size for example 8" or 10" to get more stable results.
I have tested 6" dia pipe with about 6' good results. But now i am moving toward my 8' diameter pipe to get a big long thicker and stable laminar stream
Hope this answer the question.

Thanks for your reply,
I am planning on building 4 jets for my museum exhibit. I'm only looking for a 4' to 5' stream. I did build an 8" nozzel that is 14" long. Works great but is a little too large for my exhibit. What is the shortest 8" jet I can make for a 4' to 5' jet? Great job on the cutter. I'm experimenting with a radio control airplane servo. Not sure if it's fast enough though .007 sec. I would be able to use a 4 servo controller for the 4 jets. I don't know much about electronics so I have to go the backyard mechanic route.