Prop pitch how does it work

Overspeed When you pitch the airplane down, the governor takes over again. By pitching down and not touching the engine controls, the engine will start to speed up, and the flyweights will fly outward, due to centrifugal force. As soon as that happens, the pilot valve will raise, oil will flow into the prop hub, and the pitch of the blades will increase, slowing the engine to your set speed.

All of that being said, if you run out of engine oil, you are going to have bigger problems than just a lack of prop control - chances are, your engine isn't going to run for much longer. A constant speed propeller gives you the ability to select the engine and propeller speed you want for any situation. It also makes your plane more adaptable to different phases of flight. And last off, with an extra engine control in the cockpit, it makes you look like a genius to your passengers.

Become a better pilot. Subscribe to get the latest videos, articles, and quizzes that make you a smarter, safer pilot. Colin is a Boldmethod co-founder, pilot and graphic artist. He's been a flight instructor at the University of North Dakota, an airline pilot on the CRJ, and has directed development of numerous commercial and military training systems.

You can reach him at colin boldmethod. To: Separate email addresses with commas. Now What? All Videos.

Planes Careers. Aaron Landry. Colin Cutler Colin is a Boldmethod co-founder, pilot and graphic artist. Recommended Stories. How DME Works. Fewer thunderstorms and less turbulence mean more days in the air for you. Propeller pitch is the distance the prop would move forward in one rotation if it were moving through a soft solid—think of a screw being turned into wood.

The blades on a propeller are analogous to the threads on a screw. Some propellers have a constant pitch, meaning the pitch is the same at all points from the leading edge to the trailing edge of the prop blades.

Progressive pitch starts lower at the leading edge and increases to the trailing edge. The pitch number assigned to a progressive-pitch prop is the average across the entire blade.

The pitch of a propeller describes how the blade is angled to cut into the air. Blades are subject to the same aerodynamic laws as wings, and the propeller has added rotational velocity that must be added to its forward velocity, making the flight path of propeller blades into a spiral. Changing how the blade cuts into the air and pulls air toward it changes the operational speed and power of the aircraft.

Best choice at speeds over 50mph, or if your boat is running over oyster beds or sandbars regularly. Stainless costs more but is five times more durable than aluminum. Stainless props can be repaired, at a higher cost, to like-new condition, while repaired aluminum will suffer from metal fatigue and a loss of strength.

Three or four blades work well in either sterndrive or outboard applications. Three-blade designs give you all-around performance with an advantage on top end speed. Four-blade designs work well with boats that are difficult to get on plane, underpowered or used in watersports where top-end speed is not critical.

The composite cores of modular hubs are designed to break away upon significant prop strikes, helping to protect the prop body and engine drive train from damage. Four blades in many cases will drop your rpm by 50 to rpm with identical pitch. Three-blade props are generally best for recreational boats with three-, four- and six-cylinder outboards and sterndrives, giving good hole shot and top-end performance. Adding a fourth blade increases the DAR to between 60 and 65 percent, so you can expect more thrust to keep your boat planing at lower rpm, a potential boost in fuel economy, but also a reduction of 50—rpm at WOT.

Modular hub systems consist of a hub that fits on to the splined shaft of the engine and the prop body which fits on to the hub. These systems offer two main advantages. First, in the event of a significant prop strike, the composite hub breaks away, which reduces the chance of damage to the engine, engine drive or propeller.

Also, if the prop is bent but the hub is intact, replacing just the prop is also less expensive. Unfortunately, our services and products are not available at your location. West Advisor Articles. What problems are you looking to solve? Is your engine over or under revving?