Earlier this week, we posted a slide comparing the upcoming Air Force 1 Northrop-Grumman E-2C Hawkeye AEW aircraft against the one proposed by Hobby Master. While we didn’t catch it previously, we did notice that the Air Force 1 version featured four propellers on each of the engines, while the Hobby Master replica showed eight. We queried the distributor regarding this glaring difference between the two aircraft and they indicated that the Air Force 1 version will ship as is, but will also include a second set of 8-bladed propellers. Wikipedia explains why the changes were made:

“In 2004, the E-2C’s propeller system was changed; a new eight-bladed propeller system, named NP2000, was developed by the Hamilton-Sundstrand company to replace the old four-bladed design. Improvements included reduced vibrations and better maintainability as a result of the ability to remove prop blades individually instead of having to remove the entire prop and hub assembly. The system had previously been used in the C-130 Hercules, which also uses the T-56 engine, to great effect. However, one major difference between the C-130J and the E-2C is that the C-130J uses a six-bladed propeller. The E-2C needed to use a new eight-bladed configuration in order to maintain harmonic compatibility with the electronics that were designed for a four-bladed propeller. The propeller blades are of carbon fiber construction with steel leading edge inserts and de-icing boots at the root of the blade.”

Frankly, kudos go to Air Force 1 for including both sets of propeller configurations, which take into account the changes made to the aircraft design in 2004. Its these types of details that go a long way towards making the collector happy with their purchase, much like Hobby Master’s fix for its radome oversight which came to light a few weeks ago.