The purpose of this test is to show the effects of temperature and humidity in a practical way in the environment that it will be used in.
I took a 4 foot long piece of 4 inch Blue Tube 2.0 and put two coats of gloss black paint to allow the airframe to get as hot as possible.
I then put a 4 inch bulkhead on the bottom and a nosecone at the top to simulate a completed rocket. After screwing a few rail buttons on it I put it out on a launch pad for three hours.
The maximum temperature achieved during the test on the blast deflector is 106.7 degrees at 70% relative humidity.
Location: Tampa, FL
Date: 11/1/09
Time: 1pm to 4 pm
Temperature: 89 degrees, humid, sunny.
Note: launch pad was not on level ground, nor was the rail pointing perfectly straight up.
Conclusion: There was negligible temporary deflection toward the right and no deflection on any other axis. Note that this test is exaggerated in that the entire 4 foot section of airframe was hollow and unreinforced without any motor mount tube, centering rings, or couplers.
What does this mean? It means for all practical purposes, humidity warping is irrelevant and negligible for all but the longest and skinniest rocket designs. No rocket under 6 inches should have 4 feet of hollow space in it anyway because you can't reach down into it to get to anything.
Start of test
(click on thumbnails to enlarge)
Initial temp and time.
Warp Test Start
Warp Test T+1 hour
Warp Test T+2 hours
Warp Test T+3 hours
Max Temp and RH reading