26th July 2025

Set by Peter Stuart

The Rules

 

 

LEVEL LUFFING CHALLENGE
The object of this challenge is to determine who can build the most accurate Level Luffing Crane, in terms of the consistency of the height of the hook above a horizontal surface during a luffing manoeuvre.
Rules:
1. Models of Hammerhead Cranes, Gantry Cranes and Shipping Container Cranes are not permitted because they are inherently level-luffing.
2. Models need only to be capable of luffing their jib. Slewing and travelling motions are not necessary.
3. Any known Level Luffing Mechanism can be used.
4. The luffing mechanism can be hand or motor powered, but hand operation is recommended.
5. A weighted hook is to be fitted to the bottom of the hoist cord of each model.
6. Minor height adjustment of the hook can be made before commencing a competitive luff. It is recommended that any winding drum or similar, be hand operated and self-locking. Manual adjustment of the hoist is not permitted during the luff.
7. The range of horizontal luff movement over which measurements will be taken is 12”. A 12” steel ruler will be supplied and it will lie flat on the table.
8. Height measurements of the underside of the hook above the table will be taken by judges selected on the day. Three measurements will be taken along the 12” luff at 0”, 6” and 12”, i.e., at START, HALF-WAY and END of the 12” ruler.
9. Competitors are to specify the horizontal straight line distance from the base of their crane to the start of the 12” measurement ruler.
10. Participants can use light finger touch to steady their hook from swinging, before each height measurement is taken.
11. The height under the hook will be measured using toolroom parallel bars of 3. 4 & 6mm thickness and 2-1/2” Meccano strips, 0.8mm thick, all of which will be supplied. The bars and strips will be slipped under the hook one at a time until the hook is just touching the top of the stack.
12. The three heights will be recorded and the entrant whose three figures have the lowest overall range (i.e, maximum to minimum) will be the winner.
13. A flat-top table measuring 1.5m x 0.75m will be set up in the hall, and levelled. Clamps will be available to hold models in position on the table if required. Please provide suitable anchorages on your model for the clamps to grip.
14. The judges’ decision will be final.