Figure 1.
I-31P (top) and I-23 (bottom) airplane.
Source: L-ILot.
Table 1.
I-31 Nose Landing Gear parameters
| Parameter Name | Value | Unit |
|---|---|---|
| Configuration | telescopic | - |
| Aircraft Landing Mass | 1117 | kg |
| Aircraft Landing Weight | 1096 | daN |
| Vertical Landing Speed (Limit) | 2.93 | m/s |
| Horizontal Landing Speed (Limit) | 37.8 | m/s |
| Acceleration Coefficient during landing with Limit Vertical Landing Speed | 4.86 | - |
| Maximum Tyre Deflection | 68 | mm |
| Maximum Shock Absorber Deflection | 124.6 | mm |
Figure 2.
Strain gauge placement on the NLG half-fork.
Source: L-ILot.
Figure 3.
Strain gauge configuration.
Source: L-ILot.
Figure 4.
40/20T Press.
Source: Landing Gear Laboratory, L-ILot.
Figure 5.
1st filling/charging, 0326-I31PP-st-P40-0031, for data comparison see Table 5.
Source: L-ILot.
Figure 6.
2nd filling/charging, 0326-I31PP-st-P40, for data comparison see Table 5.
Source: L-ILot.
Table 2.
Input Parameters and reference values of the tests
| Input Parameters | ||
|---|---|---|
| Parameter Name | Value | Unit |
| Shock Absorber Pressure | 0.95 | MPa |
| Tyre Pressure | 0.31 | MPa |
| Vertical Landing Speed (Limit) | 2.93 | m/s |
| Horizontal Landing Speed (Limit) | 37.8 | m/s |
| Reference Values | ||
| Vertical Force (Fz) | 17.38 | kN |
| Horizontal Force (Fx) | 6.40 | kN |
| Acceleration Coefficient (nz) | 4.86 | - |
| Landing Gear Deflection (Uk) | 183.5 | mm |
| Shock Absorber Deflection (Ua) | 115.8 | mm |
Figure 7.
M10T test stand – overview example (left), I-31 NLG mounted (right).
Source: L-ILot.
Figure 8.
Example of full-scale dynamic I-31 NLG drop tests, general results. 1st filling/charging, 0326-dt-NLGI31-M10T-064, for data comparison see Table 3.
Source: L-ILot
Figure 9.
Example of full-scale dynamic I-31P NLG drop tests, strain gauge results. 1st filling/charging, 0326-dt-NLGI31-M10T-064, for data comparison see Table 4.
Source: L-ILot
Figure 10.
Example of full-scale dynamic I-31P NLG drop tests, general results. 2nd filling/charging, 0326-dt-NLGI31-M10T-094, for data comparison see Table 3.
Source: L-ILot
Figure 11.
Example of full-scale dynamic I-31P NLG drop tests, strain gauge results. 2nd filling/charging, 0326-dt-NLGI31-M10T-094, for data comparison see Table 4.
Source: L-ILot
Table 3.
Dynamic Tests (Limit Conditions)
| Parameters | Reference | 1st charging | 2nd charging | Unit |
|---|---|---|---|---|
| Value | ||||
| Shock Absorber Pressure | 0.95 | MPa | ||
| Tyre Pressure | 0.31 | MPa | ||
| Landing angle (φ) | 0° | |||
| Vertical Landing Speed (Vz) | 2.93 | 2.93 | 2.93 | m/s |
| Horizontal Landing Speed (Vx) | 37.8 | 39.06 | 40.07 | m/s |
| Vertical Force (Fz) | 17.38 | 17.47 | 18.04 | kN |
| Horizontal Force (Fx) | 6.40 | 7.1 | 7.6 | kN |
| Acceleration Coefficient (nz) | 4.86 | 4.80 | 4.89 | - |
| Landing Gear Deflection (Uk) | 183.5 | 189.3 | 185.8 | mm |
| Shock Absorber Deflection (Ua) | 115.8 | 116.1 | 114.3 | mm |
Table 4.
Dynamic Tests (Limit Conditions) – Stress on Half Fork
| Parameters | 1st charging | 2nd charging | Unit |
|---|---|---|---|
| Value | |||
| ZD – outside (opposite to wheel axis side) bottom | 275.67 | 313.52 | MPa |
| WD – outside (opposite to wheel axis side) bottom | -316.13 | -323.31 | MPa |
| ZG – inside (wheel axis side) top | 246.59 | 248.41 | MPa |
| WG – inside (wheel axis side) top | -266.32 | -277.75 | MPa |
| Vertical Force (Fz) | 17.47 | 18.04 | kN |