Heavy Duty Portable Tripod/Mast System
MMT20 Wind Load Configurator
- Operational — Within the operational limit
- Survival — Stands, but permanent damage is possible
- Failure — Beyond the survival limit
Each cell gives the maximum operational speed and, after the slash, the maximum survival speed. Select a cell for the full calculation.
| Configuration | Anchor distance | Payload wind area A (m²) — effective drag area is Cd × A | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mast only | 0,1 | 0,2 | 0,3 | 0,4 | 0,5 | 1,0 | 1,5 | 2,0 | 2,5 | 3,0 | 3,5 | 4,0 | ||
| MMT20-Y3 | 1,4 m | |||||||||||||
| MMT20-Y4 | 1,9 m | |||||||||||||
| MMT20-Y5 | 2,4 m | |||||||||||||
| MMT20-Y6 | 3,0 m | |||||||||||||
| MMT20-Y7 | 3,5 m | |||||||||||||
| MMT20-Y8 | 4,0 m | |||||||||||||
| MMT20-Y9 | 4,5 m | |||||||||||||
| MMT20-Y10 | 5,1 m | |||||||||||||
| MMT20-Y11 | 5,6 m | |||||||||||||
| MMT20-Y12 | 6,1 m | |||||||||||||
| MMT20-Y13 | 6,7 m | |||||||||||||
| MMT20-Y14 | 7,2 m | |||||||||||||
| MMT20-Y15 | 7,7 m | |||||||||||||
Limit states: The model evaluates four limits and reports the lowest — buckling between guy rope levels, combined bending and axial stress at the payload cantilever above the top guy ring (1.0 m lever arm), rope tension, and anchor pullout. It is calibrated against the MMT20 test dataset and mapped to the catalogued configurations by piecewise power-law interpolation over height.
Wind area and Cd: Column headings are the projected payload area A. The model uses the effective drag area Cd × A with the coefficient selected above — 1.0 corresponds to an EPA figure, 1.2 to a flat plate reference.
Rope limits: Standard duty polyester MBL 180 kgf · heavy duty AISI 316 1×19 Ø3 mm MBL 950 kgf · operational tension ≤ MBL / 3.0 · survival tension ≤ MBL / 1.5. Verify the rope actually installed.
Ground and anchor limit: Ultimate pullout per anchor point — rock or concrete (bolted) 30 kN · dense gravel 12 kN · stiff clay 8 kN · medium-dense sand 5 kN · loose or wet sand 2.5 kN · soft or saturated clay 1.5 kN. Allowables are those figures divided by 3.0 (operational) and 1.5 (survival), applied as a third term in the governing minimum. Values assume the standard anchor kit — two cross-driven Ø25 × 750 mm stakes, bolted anchor in rock — and are representative. Pull-test on site for critical deployments. Rock and concrete equal the unyielding-anchor baseline. All values assume the tripod and anchors hold without movement.
Tube and serviceability assumptions: Ø88.9 × 3.18 mm, E = 70 GPa · rope pretension 100 N · rope axial stiffness EA ≈ 40 kN (standard) and 571 kN (heavy). Deflection and stress in the detail panel are indicative simplified-elastic estimates, not design values.
Scope of the model: The test data band ends at 0.372 m² effective area; larger areas are extrapolation. The three-level guy arrangement and the 100 % anchor radius carry no test data and are an engineering extension. Uniform steady wind is assumed; the evaluation ceiling is 145 km/h. Ice, fatigue and dynamic effects are excluded. Payload mass must also respect each configuration’s rating.
MMT20 · Heavy Duty Portable Tripod/Mast System · Engineering reference. It supports, and does not replace, site-specific judgement by a qualified engineer.