- #1
jetman
- 2
- 0
Hello,
I design high powered rockets in our Tripoli rocket club. A particular plastic type of tube used is the Quantum 3.9 in dia plastic (sewer pipe) it is a thin wall design. http://www.publicmissiles.com/ They state that this basic tube is good for just .86 mach for compression loads. Basically this nearly 4in dia tubing is used for rockets that are between 6 and 9 ft tall. To go above mach 1 we have the option to use fiberglass tubes or better yet carbon fiber, steel etc.
Before I spend all that money on fiberglass or carbon, I want to know what axial strength I would have roughly, if I used an outer pvc sleeve over the previous mention PML tube. (good for mach.86) The resulting double walled pvc tube would now be good for what in compression axis? 1.5 mach 2 mach etc..
The known is: The PML tube alone is good for .86 mach airspeed for compression load..BUT if i use the below listed outer tube (a white thin wall sewer pipe)..it will be stronger.
The outer tube I want to use just fits nicely over the PML tube and specifically, the outer tube is: Made by Cresline pvc DS- 3000LB CRUSH PVC sewer pipe MS ASTM D 2729.
Obviously, when you slide a PVC tube inside another tube, it becomes stronger.
Also in general, If say a known tube A for example has an axial load strength of 2000lb then tube B of axial strength 1500...if bonded together with epoxy or silicone etc..and tubes cut flush on ends...will the new load simply be A+B= 3500? or is there a higher increase, a synergistic effect when tubes are layered? I realize an accurate way to find out is load test a 12 in piece of tubing that has the tube glued inside another...but, I don't have such testing equipment.
*My current rocket design will reach mach one almost at 700MPH for just a few secs..then the speed will decrease over 30 sec to just 30 mph at apogee.
The main point is, I need stronger tubing for my rocket project that will just barely reach 700mph. The PML tube alone is not quite good enough (.86 mach) I will be at least 1 mach...can my double tube do it...surely it can, but I need Data!
Thanks,
Michael Tampa
Tripoli Cert Level 2
I design high powered rockets in our Tripoli rocket club. A particular plastic type of tube used is the Quantum 3.9 in dia plastic (sewer pipe) it is a thin wall design. http://www.publicmissiles.com/ They state that this basic tube is good for just .86 mach for compression loads. Basically this nearly 4in dia tubing is used for rockets that are between 6 and 9 ft tall. To go above mach 1 we have the option to use fiberglass tubes or better yet carbon fiber, steel etc.
Before I spend all that money on fiberglass or carbon, I want to know what axial strength I would have roughly, if I used an outer pvc sleeve over the previous mention PML tube. (good for mach.86) The resulting double walled pvc tube would now be good for what in compression axis? 1.5 mach 2 mach etc..
The known is: The PML tube alone is good for .86 mach airspeed for compression load..BUT if i use the below listed outer tube (a white thin wall sewer pipe)..it will be stronger.
The outer tube I want to use just fits nicely over the PML tube and specifically, the outer tube is: Made by Cresline pvc DS- 3000LB CRUSH PVC sewer pipe MS ASTM D 2729.
Obviously, when you slide a PVC tube inside another tube, it becomes stronger.
Also in general, If say a known tube A for example has an axial load strength of 2000lb then tube B of axial strength 1500...if bonded together with epoxy or silicone etc..and tubes cut flush on ends...will the new load simply be A+B= 3500? or is there a higher increase, a synergistic effect when tubes are layered? I realize an accurate way to find out is load test a 12 in piece of tubing that has the tube glued inside another...but, I don't have such testing equipment.
*My current rocket design will reach mach one almost at 700MPH for just a few secs..then the speed will decrease over 30 sec to just 30 mph at apogee.
The main point is, I need stronger tubing for my rocket project that will just barely reach 700mph. The PML tube alone is not quite good enough (.86 mach) I will be at least 1 mach...can my double tube do it...surely it can, but I need Data!
Thanks,
Michael Tampa
Tripoli Cert Level 2