MMT20
Wind Load Configurator
Maximum wind speed each MMT20 configuration withstands, for a given payload wind area, guy rope arrangement and ground condition.
- 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-X8-1400-8020-0065-C01 | 4.0 m | |||||||||||||
| MMT20-X3-1400-2720-0085-C01 | 1.4 m | |||||||||||||
| MMT20-X4-1400-3780-0080-C01 | 1.9 m | |||||||||||||
| MMT20-X5-1400-4840-0077-C01 | 2.4 m | |||||||||||||
| MMT20-X6-1400-5900-0073-C01 | 3.0 m | |||||||||||||
| MMT20-X7-1400-6960-0069-C01 | 3.5 m | |||||||||||||
| MMT20-X9-1400-9080-0062-C01 | 4.5 m | |||||||||||||
| MMT20-X10-1400-10140-0058-C01 | 5.1 m | |||||||||||||
| MMT20-X11-1400-11200-0055-C01 | 5.6 m | |||||||||||||
| MMT20-X12-1400-12260-0050-C01 | 6.1 m | |||||||||||||
| MMT20-X13-1400-13320-0045-C01 | 6.7 m | |||||||||||||
| MMT20-X14-1400-14380-0040-C01 | 7.2 m | |||||||||||||
| MMT20-X15-1400-15440-0035-C01 | 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.
Engineering reference. It supports, and does not replace, site-specific judgement by a qualified engineer.