Outrage Rotorhead Geometry

Written by Ashley Davis Friday, 24 April 2009 09:01

Geometry

The G5 has been out for a while now and I felt it was time to start putting together some useful info on how to get best out of this superb little 450 class machine. The Outrage 550 is also out and shares a very similar head setup. So why not combine two articles in one and look at how to setup both from a head geometry perspective. One of the initial problems faced by new Outrage owners is that the head geometry is nothing like the Align series of helicopters. Align have been so successful with their heli's that many heli owners just haven't experienced different head geometrys so when initially faced with the Outrage head there is a fundamental lack of understanding of how to adjust and set it up properly. This article is to address that understanding gap and introduce the new Outrage owner to their rotor head geometry.

Outrage head explained

outrage-head

Above we have the outrage head (picture taken from the Outrage 550 manual). The Outrage head is the same layout/geometry on both the G5 and the 550, however, the 550 head has more adjustments available. This picture actually gives us a good overview of what the head should look like at 0 degrees pitch. However, before I go into detail let me explain the various parts.

Working top down:

Head button: this is just a handy device for making it easier to place your hand on the rotor head to slow the blades. It also can be touched on the ground in inverted hover without any vital control surfaces making contact with the ground. From a configuration perspective it obviously serves no purpose.

Blade grip: these are what hold your blades. They are both ball raced and thrust raced on the Outrage helicopters and should move freely without any effort. If your blade grips are stiff or feel like they are grinding when turned then there is likely some issue with your bearings or how you have installed the bearings into the blade grips. The blade grip arms have multiple positions for the upper mixer, closest to the end of the arm giving fastest response and vice versa.

blade-grip

Upper mixer: This mixes the collective and cyclic inputs from the swashplate. This mixer is used to setup how fast you want your cyclic as well as used for adjustments to tracking. This is where we will be doing most of our 'tuning' to get the head to respond they way we would like, notice the orientation of this mixer with two holes on the left and three holes on the right, it's very easy to put this on backwards. More on this later.

upper-mixer

Flybar cage: Controls the flybar as well as holding the flybar in position. Translates cyclic inputs (swashplate movements) into changes at the flybar and the blades.

Washout arms: The washout on a rotorhead assembly is a series of components, usually a base and two arms, mounted on the mainshaft which transmit cyclic movements to the flybar without being affected by collective pitch changes. Notice the washout arms sit horizontal forming a 90 degree angle shown on the diagram when the collective pitch is at zero degrees.

Linkages

Also on the diagram you can see three linkages. Their function and use is explained below.

Linkage A: Generally this linkage is not changed from the factory recommended settings. It's purpose is to anchor the mixer arm at one end and provide a point for the mixer. Depending on which hole you use the arc the mixer pivots through is changed. So in general where this link is anchored (which hole on the nmixer) is actually more fundamental than how it has been adjusted. It's length can be adjusted and in general this will make very fine changes to the blade angle and tracking of the blade it is adjusting. Additionally the flybar provides input to the blades through this linkage, this again is not dependent on it's length but where the ball is positioned on the flybar carrier (also called flybar seesaw) at it's lower anchor point. The closer you move the anchor ball to the rotor hub the faster the cyclic response from the helicopter and vice versa, this adjustment is available on the Outrage 550 but not the G5 (see below).

flybar-carrier

Linkage B: This sets the distance between the washout base and the flybar cage and again this linkage has a factory recommendation and shouldn't require adjustment. The only critical element is that each of these links either side of the flybar cage should be equal in length. The overall length defines how far the washout base sits away from the flybar cage at 0 degrees pitch, so in theory increasing the length of these links can give you a little more washout travel to work with. However, I would not recommend changing these a great deal from the recommended lengths in the manual as the washout pins are only so long and making these linkages too long could cause the washout to dislocate from the pins at minimum collective pitch...... which would be rather disasterous inflight.

Linkage C: This is your main link from the swashplate up to the upper mixer and it's primary function is to introduce collective pitch to the main blades. Adjusting this rod adjusts your overall tracking for the blade and should be the first rod changed to make tracking adjustments (coarse) and then linkage rod A can be used for minor adjustment once you have got it near enough tracked. It should be possible to track the blades on this rod alone but sometimes a little adjustment on linkage A can get it spot on. Notice that this rod makes a 90 degree angle with the upper mixer at the top. This is imperative if you are to get equal collective pitch travel above and below zero degrees pitch. This 90 degree angle is formed at 0 degrees pitch and both linkage rods (C) should be adjusted together to form this 90 degree angle on each upper mixer. Once done the rods can be adjusted by one to two turns to bring the tracking into line during test flights.

550 overview video

Servo configuration for the G5

At zero degrees pitch the servo horn for all cyclic servos should be horizontal. Pictured below is a typical servo used in the G5. You can see I've chopped down the arm to an appropriate length and will be fitting the linkage ball in the furthest remaining hole from the servo center. If you have different servos with different servo horns then the distance from center to ball is approximately 13mm.

G5 overview video

Servo configuration for the Outrage 550

The Outrage 550 uses a push pull system so you have two linkage balls on each servo horn. The manual again states the correct distances to use for the model. The diagram from the manual (page 9) is included below as a reminder.

550 servo

Paddles

The stock G5 just has ordinary paddles which can only be set for one speed setting. The 550 has the X3D style paddle (available as an upgrade for the G5).

The X3D style paddle has two positions into which the flybar can be inserted. The hole closest to leading edge gives a standard level of response and the rearward hole gives an 'advanced' level of response.....or more accurately stated 'crazy levels of response'. Most will want to opt for the hole closest to the leading edge of the paddle as this is the most stable and less likely to induce panic ;-)

Conclusion

I hope this has been a useful overview of the Outrage head and the various settings for it's geometry. It was not intended to be a setup guide for collective pitch or indeed cyclic pitch, just an overview of what is available in terms of configuration on the rotorhead and what effect the different settings have.

In a future article I will go into setting up collective and cyclic pitch, also you can find information on collective pitch 'S' curves elsewhere on the site.

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