GA a/c with 2/3 bladed props?

[barryward12345 0]

I have 2 GA a/c - the Carenado Mentor and the Flight1 Commander 112A which both come in either 2 or 3 bladed prop versions.Could somebody kindly give me a bit of a rundown on the differences between the 2 types of prop - advantages disadvantages, etc.ThanksBarryBazza in Brisbane, Australia

[Guest Crimguy]

2 blades is generally a more sensible design from an efficiency standpoint. 2 blade props spin up faster which is useful for smaller horsepower engines.However, 3 and 4 blade props, when balanced properly, can provide a smoother experience (less vibration that is), and when you start getting over 250-300hp, the loss in acceleration of the prop is less apparent, if not at all.

[ejoiner 21]

The mentors modelled by Carenado are more or less modelled on the T-34A and T-34B models. The A model was for USAF and the B model was used by the Navy. One of which was authorized for acrobatic manuevering and the other was not. (I think the Navy B wasnt). I actually have the real manuals for both airplanes I can go look it up..I do not think Carenado made ANY FM adjustments between the two birds. Both of which are fully acrobatic. I painted a number of skins for both models and replacement panel upgrades as well in the avsim lib.Eric

[DaryllB25840 1]

Barry,Prop selection is a function of engine selection. The prop must absorb the horsepower that the engine creates and transform it to thrust. As pointed out the two blade is more efficient and a designer would select the largest diameter two blade for a given horsepower. The limiting factor is ground clearance as the prop diameter increases. When it is found that there is not enough prop tip to ground clearance when the tail is off the ground ready for lift off during the take off run or when the tricycle configuration doesn't allow for sufficient clearence the designer has to go to a 3 or 4 bladed prop to maintain a given load factor on the engine.This is most evident in the F4U Corsair's gull wing. The F4U had gull wings to achieve the prop tip clearence for the large 4 bladed prop.Daryll