Truck or trailer flag pole

If you use guy wires to help distribute the load , conduit might work . Two inch pipe would probably work better , but IN MY OPINION you'd still need to put guy wires on it . I ride with PGR when there's a mission close enough to me ...

Maybe rigid conduit, but I would think EMT is a little flimsy, but it might work. That's quite a bit of flapping. I'm surprised the flags themselves don't fray. My guess is that the energy put into the flag/pole system is proportional to the area of the flag and to the square of the speed. I think most flags are used at sub-highway speeds. Then again, what do I know?
GWE

Flight line flags - bumper mounted in one of the real bumpers chrome carriage bolt...
It was a 2" pipe maybe just larger - as the other pipe slid inside that held the flags.
The multi-star or various color flags were needed to be able to handle high speeds. High speed was to get across a runway or tarmac fast, out of the way or to the site fast. Cold War days and likely today.
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member.
J> I am trying to figure out how to make a flagpole to mount on my truck and

Are you doing this often? If so it may be worth the expense of a bit of 2 X 2 X 3/16 square tube in a "L" shape. Perhaps coming from your reciever hitch (doesn't every truck have one?) and up about as high as the top of the tailgate. I would then take a 7' section of 1" black pipe as the mast. That should get the top about 8.5 to 9' high depending on the hieght of the hitch. Remember you will have underpasses and wires to consider. You could even paint the screw on cap a silver or gold to pretty it up. A 1/2 diameter eye bolt in the top cap would give an attachment for the guy wires/ropes which could also have colored pennants on them. I think I would also use this ring to tie the top of the flag to. The bottom could be simply tied around the pipe with a hose clamp over it to hold it in place. Lastly I bet a 1.25 or 1.5" piece of pvc pipe or hose would fit over the black pipe and fit inside the 2X2 fairly tight. Because of the stresses at the highway speeds I would avoid drilling any holes in the mast.
And depending on how long a ride you will likely need a flag per outing.

Sorry to top-post but we use Off-Road flags for trucks, quads and sand-rails. They are fiberglass two, or three pc. lengths up to 12' in elevation (Minus the mount height) Any off-road supplier such as should do the trick, even with the larger flag. The other thing that pops to mind is checking with a local heavy construction firm near you. Given the circumstances I would hope they could help out.
And mostly- Thanks for taking the time to watch our butts!!
Respects,
Rob