Altimeter Cloud
The rules for 2026 say that your rocket must be made from body tube at least 47mm in diameter.
In our opinion the Klima 50mm tube is a great choice to meet this specification, it's wall thickness is a little bit stronger than the BT type tubes.
You could also pick BT-70 tube as a great option too.
If you require a slightly wider rocket then the BT-80 or Klima 75mm tube can also be used.
In terms of strength we find the Estes "BT" tubes to have the thinnest walls, the Klima tube is a bit stronger, and the LOC cardboard tube is the strongest of all. Phenolic tube from LOC / PML or Black cat is even stronger but probably is over specified for the UKROC challenge and will introduce unnecessary weight in our opinion.
If you can't find the tube you're after then please check out our full section here although we've included pretty much everything you might need already here.
