From the data shown in the illustration,...

Question 1 of 270705eccefa1bacbc34ba4d4719c

From the data shown in the illustration, what would be the speed of the L.P. turbine rotor if the propeller shaft was turning at 90 RPM? See illustration SE-0022.

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Question 1 of 27070

From the data shown in the illustration, what would be the speed of the L.P. turbine rotor if the propeller shaft was turning at 90 RPM? See illustration SE-0022.

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🔍 Key Concepts

• Use the gear ratio formula: speed ratio is inversely proportional to the number of teeth on meshing gears. • This is a double-reduction gear train: propeller shaft → 1st reduction pinion/gear → 2nd reduction pinion connected to the L.P. turbine rotor. • Overall ratio = (1st reduction ratio) × (2nd reduction ratio), all using the L.P. tooth counts from the illustration.

💭 Think About

• Identify which gears and pinions belong to the L.P. (low-pressure) turbine train and ignore the H.P. (high-pressure) numbers. • For each mesh, set up the relation: (RPM of gear) × (its teeth) = (RPM of mating pinion) × (its teeth). How does this change speed from the propeller shaft to the next shaft, and then to the turbine rotor? • After you find the overall speed ratio, multiply it by the 90 RPM of the propeller shaft. Which option is closest to that result?

✅ Before You Answer

• Be sure you are using the Bull Gear 506 teeth meshing with the L.P. 1st reduction pinion 47 teeth for the first ratio. • For the second ratio, use the L.P. 1st reduction gear 124 teeth with the 2nd reduction pinion 43 teeth as shown in the illustration. • Before picking your answer, confirm that you multiplied the two ratios together (1st and 2nd reduction) and then applied that to the 90 RPM propeller speed.