DESCRIPTION

TECHNICAL FIELD

The invention describes evaluation technique for Power Take Off (PTO) shaft alignment in LCA Tejas Aircraft.

BACKGROUND OF INVENTION

PTO is a method of taking power from a power source, such as running engine and transmitting it to an application, such asits attached- machine:"In aircraft application the power-source will-be the Engine and the transmitting end will be the Gear Box which in turn powers the various systems of aircraft such as Hydraulics, electrical etc. The Power take off will be transferred through a shaft from engine to gear box by rotary motion. It necessitates proper methodology to install and check the PTO shaft alignment, as any deviations in concentricity and parallelism may lead the reduction in transmission efficiency and endanger the life of pilot and aircraft.

SUMMARY OF INVENTION

On LCA- Tejas aircraft PTO shaft is connected between the aircraft engine and aircraft mounted gear box (AMAGB). Its main purpose is to transmit the power from engine to gear box by rotary motion for functioning of various other aircraft systems and is also required for pulling the power to engine during its start.

As this is the only media of getting power for other system to perform, it became important to check its alignment for better performance. Three parameters namely parallelism, concentricity and length of shaft have been identified as variables to achieve the alignment of PTO shaft after installing engine and before the sortie.

PROCESS DETAIL DESCRIPTION

1. Ensure the inclination of installed AMAGB should be within limits as per the : Installation Drawing.

2. Check for the installation of the IDG, JFS, HP-1 and HP-2 on AMAGB.

3. Concentricity checking procedure:
a. Fix the DTI stand on the AMAGB Pad with the three bolts.
b. Fix the Dial Gauge Indicator Needle Type on the DTI stand and pull out the Gear box
(AMAGB) pad so that the needle of the indicator should touch the Engine pad.
c. Slowly rotate the AMAGB pad for one rotation andcheck-for-themaximum deflection-point:
d. Then rotate the AMAGB pad again till it reaches to the opposite end of the maximum .
deflection point and set zero in the gauge indicator at this point.
e. Slowly Rotate the AMAGB pad upto the maximum deflection point and check the gap
between the Engine pad and the Needle with the help of the Slip Gauges.
f. Record the value. (Concentricity= Measured Value / 2).
g. Offer for inspection.

4. Parallelism checking procedure:
a. Remove the Needle type Dial gauge Indicator and fix the Plunger type Dial gauge Indicator
. on the DTI stand such that there should be the preloaded nominal pressure on the plunger.
b. Set the zero on the indicator at that point.
c. Slowly rotate the AMAGB pad and keep watching the reading on the Dial gauge. Note down
the maximum and minimum reading for one complete rotation.
d. Record the values. (Parallelism = Max. Value - Min. Value).
e. Offer for inspection.

5. Gap measurement procedure.
a. Remove the Plunger type Dial gauge Indicator from DTI stand and then remove the DTI
stand by removing the three bolts, keep the bolts safely.
b. Check for the AMAGB pad to be in the extreme out position.
c. Set the Internal micrometer for the gap between the two pads.
d. Take reading between the two opposite points on the AMAGB pad and EGB pad, at
minimum four places. And Record the same.
e. Then push AMAGB pad to extreme in position.
f. Again take reading between the two opposite points on the AMAGB pad and EGB pad, at
minimum four places. And record the same.
g. Offer for inspection.

Required tools/ Ground Support Equipment:

1. Dial Test Indicator Stand.
2. Dial Gauge Indicator Plunger Type P/N: MET/434
3. Dial Gauge Indicator Needle Type P/N: MET/538
4. Slip Gauge P/N: MET/114
5. Inspection Mirror
6. Internal Micrometer P/N: MET/539
7. Hex Bolts P/N: 3003A-6-18
8. Spot Light
9. 10MM Ring Spanner
10. 3/8" Spanner Combination set.

CLAIMS

We claim the methodology of checking the alignment of PTO shaft on LCA Tejas Aircraft.