Moonraker 4

[dusty4468]

I am just getting back into CB's after MANY years off. I am slowly remembering some of the info that I forgot... My question is this: I have a 30' tower with a 20 ft stinger on top..It is guyed well, so can I put a set of Moonraker 4's on the top without worrying about them being too heavy? Would it be better to drop the stinger to 10 ft due to wind resistance? Any help would be great.. BTW I will probably be asking a LOt more questions in the near future...lol

 

[Captain Kilowatt]

Stinger? Do you mean a mast? Even ten feet is plenty long for a Moonraker 4. I wouldn't do it unless the tower was guyed real well and the mast was at least a 2 inch OD pipe, not tubing. A Moonraker 4 has a wind loading of 5 square feet and will put quite a drag on the mast in a high wind. I ran a similar antenna,a Shooting Star, and used a 2 inch black-iron pipe for a mast.

 

[GnG8d]

2 inch OD pipe, not tubing.

Why use a pipe? It takes a thicker wall to have the same bending strength as tubing.

 

[Captain Kilowatt]

Really? How so? I have seen pipe stand up where tubing has failed. Tubing is typically thin walled and not as strong as pipe. That is unless you or I are defining pipe or tubing as something that it is not.

 

[GnG8d]

Pipe has threads on the OD, is measured on the ID and is meant to keep pressure (like steam) inside. Tubing is measured on the outside and is meant to be used in fabricated structures.

 

[hookedon6]

Why use a pipe? It takes a thicker wall to have the same bending strength as tubing.

pipe is measured ID, tubing is measured OD.

"2 inch OD pipe" (assuming 1/4 wall) is really 1 3/4" pipe

perhaps the reason for using 2" OD "pipe" is to properly fit the hole in the mast.

 

[Captain Kilowatt]

Pipe has threads on the OD, is measured on the ID and is meant to keep pressure (like steam) inside. Tubing is measured on the outside and is meant to be used in fabricated structures.

Well I may have just learned something new. In any event the pipe/tubing I used for a mast was 2 inches OD and did not have any threads on it as it was a piece of leftover pipe/tubing I got from somewhere years ago. I think it was an old water or steam pipe I'm not sure. All I know is that it has withstood nine square feet of wind loading in category 2 hurricane force winds and I am happy with it.

 

[Captain Kilowatt]

pipe is measured ID, tubing is measured OD.

"2 inch OD pipe" (assuming 1/4 wall) is really 1 3/4" pipe

perhaps the reason for using 2" OD "pipe" is to properly fit the hole in the mast.

Actually it would be 1 1/2 inch ID with 1/4 inch wall but who's counting. :tongue:

 

[hookedon6]

Actually it would be 1 1/2 inch ID with 1/4 inch wall but who's counting. :tongue:

:headbang i'm still burnt out from watchin the wedding,.................. Dain Bramage

there really isn't any actual difference (ASTM standard wise) between pipe & tubing, there is some informal & regional different term usage
Pipe is always thicker (OD)than tubing of the same nominal size.
piping is normally "used as is". Piping is rarely bent while tubing often is.
Joining methods differ. Piping is typically welded, flanged, or screwed. Tubing is often connected with solder or compression fittings.
"square" tube is not tubing at all,..... it's HSS (Hollow Structural Sections)
These are not hard & fast rules. Rather numerous exceptions can be found.

 

[GnG8d]

In any event the pipe/tubing I used for a mast was 2 inches OD and did not have any threads on

Bulk pipe is purchased without threads and pipefitters use a pipe threader on site as the pipe is cut to length. Lowes, Home Depot etc with sell precut, prethreaded lengths.

But without all the boring details, NASCAR, NHRA and other sanctioning bodies require roll cages be made from tubing, not pipe