[TowerTalk] Homebrew Crank-up

[jimlux]

Kevin Normoyle wrote:
> Stan Stockton wrote:
>> As mentioned the lower section would be large (33 inch face) tower  
>> with 3 inch diameter legs.  The top would either be 55G or 65G.  
>>   
> It doesn't matter whether you analyze the top section as if it started 
> on the ground or on top of something else.
> It's the same analysis. right?. (except higher wind higher)
> 
> the first post said
> 
> "about 75 feet of 55G or 65G that would telescope into about the same 
> length of larger tower (33 inch face, 3 inch legs),"
> 
> Even chopping 15' off that for a joint, you're saying 60' of unsupported 
> 55g.
> I guess you could say you're designing for 0mph wind. The problem is you 
> want to design for close tolerances, so the top doesn't bang around a 
> lot in a slight wind. But if it bends, then the tight tolerances mean it 
> won't come down. So knowing whether the top section is going to bend 
> seems important.
> 

I think one could design the supports so that it can take quite a bit of 
flex, without binding. Rollers are one approach.