Contra rotating propellers

As the forward speed increases, however, the spiral elongates and becomes less effective. The pinion meshes with the upper main drive gear, and turns it clockwise.

The Mark 13 torpedo contains a smaller explosive charge: Custom built ability encompasses exotic metals such as Titanium, Stainless Steel and Super Duplex alloys. At the time of its introduction, the An was the largest aircraft in the world and is still by far the world's largest turboprop-powered aircraft.

The characteristics of the D engine and its propeller make it a propfan, a hybrid between a turbofan engine and a turboprop engine. Between the after bevel gear and the crosshead are a bearing washer and a thrust bearing.

This drag ring is not used when the torpedo is rigged with a parachute stabilizer. The blades of the second turbine curve in the opposite direction from those of the first turbine.

The propeller efficiency is increased by recovering energy from the tangential rotational flow from the leading propeller. The thrust of the propeller is stronger than that of the gears.

This feature is necessary because the torque developed by a single propeller would tend to roll the torpedo in the opposite direction. The Short Sturgeon used two Merlin s with contra-rotating propellers. The upper and middle bearings support the first turbine spindle.

Aircraft propulsion and lift[ edit ] Contra-rotating propellers on a modified P aircraft. Contra-rotating propellers are used on torpedoes due to the natural torque compensation and are also used in some motor boats.

Contra-rotating propellers

Because of the high velocity at which the combustion gases strike the turbines, the turbine wheels must turn at high speed in order to use the available energy efficiently. So if we have a system more efficient, allowing more easy handling, why it is not used on all aircraft.


The crosshead transmits the forward thrust through the A-frames and the turbine bulkhead to the shell of the torpedo.

Main Engine of a Mark 15 Torpedo 12E1.

Propeller (aeronautics)

Gear train Figure 12E2 is a schematic diagram of the main engine. To keep this action from interfering with the steering mechanism of the torpedo, the main engine is balanced. A Mark 46 Mod 5A torpedo is inspected aboard a destroyer in April Contra-rotating propellers have benefits when providing thrust for boats for the same reasons.

When the torpedo is under way, the main engine space is filled with a fog of oil. The after propeller shaft passes through the cross-head in a floating bronze bushing.

The Convair R3Y Tradewind flying boat entered service with contra-rotating propellers. The torpedo will then leave a heavy wake of smoke. Volvo Penta have launched the IPS Inboard Performance System[3] an integrated diesel, transmission and pulling contra-rotating propellers for motor yachts.

Aircraft torpedoes must be able to withstand heavy water impacts. The others all have the same diameter inches-so they will fit the standard torpedo tubes.

Mark 14 and 23 types. An aircraft propeller, or airscrew, converts rotary motion from an engine or other power source, into a swirling slipstream which pushes the propeller forwards or backwards. It comprises a rotating power-driven hub, to which are attached several radial airfoil-section blades such that the whole assembly rotates about a longitudinal blade pitch may be fixed, manually variable to a few.

The contra-rotating propeller (CRP) system is the representing example of such devices. Unfortunately, however, neither a design method nor a full-scale performance prediction procedure for the CRP system has been well established yet.

Contra Rotating BL System 375W

Contra Rotating BL System W I ordered a new set of propellers and hope it will work. It seems the currently installed props don't flex alike on the two sides and couse the vibration by passing each other.

verified_user Quality: The 10x6 " contra one (closest to the engine) is unbalanced up to an enormous rate!! '(The other prop /5(25). UPDATED 24 January What We Need for 21st Century Combat? "The way to build aircraft or anything else worthwhile is to think out quietly every detail, analyze every situation that may possibly occur, and, when you have it all worked out in practical sequence in your mind, raise heaven and earth and never stop until you have produced the thing you have started to make.".

Propellers form rotational streams when rotated.

Contra rotating propellers topics

The stream called propeller slipstream tends to hit the vertical stabilizer creating an unwanted yawing moment. Having a propeller rotating in the opposite direction behind the original propeller cu.

The AEHS web site gets about a million hits per month.

Contra-rotating propellers

Last August, one of these hits brought a wonderful surprise in the form of an e-mail from a gentleman named Robert Aukerman regarding a presentation I gave at the AEHS Convention.

Contra rotating propellers
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Propeller (aeronautics) - Wikipedia