Cessna 170 Extreme Setup

From Flex Innovations Wiki
(Redirected from Cessna170PNP/ExtremeSetup)
Jump to: navigation, search

Cessna 170 PNP Extreme Setup

The Flex Innovation Team's Cessna 170 Extreme Setup alters the flap behavior and adjusts other elements to allow the Cessna 170 to do maneuvers well beyond those of it's full-scale counterpart, even into the '3D' realm. The Aura 8 and its powerful features are a key part of this capability. It allows the flaps to be reconfigured with the flip of a switch from 'conventional flaps', to 'prop blasted' ailerons with gyro enhanced stability, or 'crow' with gyro in the loop on all 4 wing control surfaces.

The key elements of the Extreme Setup are typically:

  • A software change via downloaded Aura Config File (.acf) that activates the flaps as ailerons and includes gyro inputs in specific flight modes.
  • Modified flap linkage and geometry to allow the flaps to move up and down and to act as 'Ailerons', etc.
  • Use of a 6S Battery (typically though not required) for awesome power.

Below you will find conversion instructions and more detailed descriptions of the Aura Flight Modes. The process is quite easy, though it is described in great detail!

Flight Modes and Flying

Your new Flight Modes are ALL gyro enabled. By default, the Flight Modes are changed by a 3-position switch assigned to the CH5/Gear channel data. No changes to the transmitter program are made (other than possibly adjusting the flap travel amount). You use the stock setup as in the manual. If a Master Gain is desired, you can assign it to each Control Mode as desired as described in the Aura User Guide.

Flight Mode 1 - Crow

We call this Crow Mode. During crow, the flaps go down and the ailerons goes up. This is to increase drag and to reduce lift. This is useful to do landings requiring short approaches. The airplane will also maintain slower speeds during steep dives. You will notice the crow is linked to the throttle. At mid-throttle and higher the mixing is off, mid-throttle to low mix is on. The mix is linear and will reach maximum crow when the throttle is at the fully down position.
The flaps have their own gyro loop (Control Mode E). This means that in Flight Mode 1, the flaps respond to gyro inputs from the roll axis. This is very helpful when you are flying under gusty wind conditions at slow speed, it makes your aircraft significantly more stable in roll axis. Flaps continue to operate as before, but at a slightly lower amount of deflection.
In summary:

  • Low dual rate aileron, high dual rate elevator/rudder
  • Low gyro sensitivity for aileron, high gyro sensitivity for elevator/rudder
  • Rudder to aileron mix, rudder to elevator mix (for coupling) - OFF for Crow Mode
  • Crow with ailerons up, and flaps down. Mixed to throttle so that crow is removed as throttle is advanced.
  • Throttle to elevator mix to compensate for crow effects
  • Flaps are in the roll axis gyro loop

Flight Mode 2 - Sport Aerobatics

This Sport Aerobatic Flight Mode remains the same as the Flight Mode 2 provided with the stock program.
In summary:

  • Low dual rates on all surfaces
  • Low gyro sensitivity on all surfaces
  • Standard flap function
  • Rudder to (opposite) aileron mix and rudder to elevator mix (for coupling)
  • Flaps are NOT in the roll axis gyro loop

Flight Mode 3 - 3D Aerobatics

This is the 3D or Extreme Flight Mode. The flaps will work as ailerons. In other words, flaps will not only be flaps but also will be ailerons. Flaps functioning as ailerons will bring a larger aileron area which will result in noticeably more roll authority and rate. Because the flaps are in the prop blast zone, the aircraft will have increased aileron authority at slow speed as well. Maneuvers like Harrier rolls are possible. The flaps also have a gyro loop (Control Mode E) which brings extra stability when the aircraft is flying at slow speed or in Harrier attitude. The flaps continue to operating as before with stock program, just with slightly less deflection.

In summary:

  • 3D (high) dual rates on all surfaces
  • High gyro sensitivity
  • Flaps mixed to work as ailerons in roll
  • Flaps are in the roll axis gyro loop
  • Rudder to (opposite) aileron and rudder to elevator mix (for coupling)

This extreme “3D” step will bring your Cessna 170 to an aerobatic and performance level that will take your imagination beyond what you expect from an airplane of this class. If you have any questions, please call us at 866 310-3539 or write E-mail Flex Support

Conversion Instructions

Part 1: Generate the new Aura Config File (Model Settings) and load into Aura

Requirements to proceed:

  • Cessna 170 Aircraft
  • Must be using Receiver to Aura connection OTHER THAN 4 wire PWM (servo leads) which is NOT supported by this procedure due to lack of ports available.
  • Micro B USB Cable (came with plane)
  • Windows PC or Tablet
  • Aura Config Tool (Windows Application for Aura)

Aura preparation steps:

  1. If you do not have it already, Download and Install Aura Config Tool
  2. Launch the Aura Config Tool and Connect to Aura (for first time users, detailed instructions on the use of the Aura Config Tool can be found Here and Here, and an Aura video playlist can be found on the Flex Innovations YouTube Channel.
    If you have previously flown and trimmed your Cessna 170, we recommend Reading from Aura then doing a Save As (to a folder on your windows device) of your existing Aura settings for future use or reference. You can also reference/note, and manually transfer Aura Servo Port Sub-trim values if you prefer.
  3. In the Aura Config Tool, choose FILE -> NEW AURA CONFIG FILE WIZARD.
  4. If you are not connected to your Cessna Aura, Choose Aura type: CESSNA 170 in the dialog box that appears.
  5. In the New Model Wizard, Name your Config, then choose CESSNA 170 EXTREME in the Control Template Box
  6. Fill in the other required fields to match your Transmitter, Receiver, and Connection type.
  7. Note the Servo Port assignments at the bottom of the Wizard.
  8. Finish the Wizard, and you will be placed in the Aura Config Tool editor with your extreme config file loaded.
  9. Write All to Aura. Disconnect the flap pushrods, then power up your transmitter and aircraft and check the basic connectivity and functions (Aura adjustments continue after mechanical changes)
  10. Make any other changes as needed. Ex. You can adjust subtrims in the Servo Ports Tab. Remember to Write All to put the changes in effect and to save your work in a folder in your windows device.

Part 2: Mechanical Changes to Flap Linkage and Aura Adjustments

Requirements to proceed:

  • As above
  • Alternate Flap Pushrods (included with aircraft)


  • The mechanical changes that need to be made to aircraft are simple. The Cessna comes with additional flap pushrods that are longer than the stock (installed) pushrods. These need to be swapped.
  • The flap servo arm will need to be placed 90 degrees to the servo (Flaps Up, Ailerons Centered), then adjust clevis so the flap is in neutral position. This allows the flaps to travel in both the up and down direction, much like ailerons.
Servo Arm Orientation


  1. Remove both flap pushrods
  2. Re-Program your transmitters CH6/Flap settings using the Aura Live Data and Aura Input Monitor (bottom of setup tab) to achieve this input.
    1. Flaps up: 0%
    2. Flaps Middle: -60%
    3. Flaps Full: -100%
    4. Flap speed about 2 seconds
    5. Flap to elevator mix: 0, 17%, 21% Down Elevator
  3. Power up Transmitter and Aura, and select FM3 (3D) and Flaps 'Up' to obtain the 'retracted' flap command (Flap Servo Port live data should show about 0%
  4. Remove the flap servo arm and rotate to a new position 90 degrees to the servo body
  5. If the Flap servo arm needs Aura Sub-trim to obtain 90 degrees, go into the Aura Config Tool Servo Ports Tab and Sub-trim the correct flap servo as needed.
  6. Install the new (longer) flap pushrods
  7. Adjust the length of the pushrods until the flaps are correct in the 'retracted' position (aligned with the wing).

Checks and Troubleshooting

  • Repeat a Flight Controller Sensor Direction Test and Transmitter Command Test which can be found HERE, or in the Cessna manual on page 14. Do all checks, but especially confirm the flaps are following in same direction as the main ailerons during roll in FM3 (3D) (though speed, distance, and characteristics will be different).
  • Check the function of the 'conventional flaps' in FM2 (Conventional) using the CH6/Flap switch on the transmitter.
    • The flap motion is controlled by the transmitter CH6 data, same as on the 'conventional Cessna'. Make adjustments (Travel, Direction, etc.) in the transmitter as needed to obtain the desired flap movement in FM2.
  • Check the function of the 'crow' speed brakes in FM1 (Crow). The ailerons should move 'up', and the flaps should move 'down' proportionally as the throttle is moved from half to idle.
    • The main crow mix (throttle to CH22 (aura crow)) is Aura Mixes Tab -> Mix 2. (Also CH22 crow data is included as a source in the custom aileron/flap servo ports). The value of the mix will adjust the amount of crow.
      • If your crow is in the upper section of the throttle stick instead of the lower (not using Aura Throttle port/reversed throttle?), move the Mix data from 'mix rate negative' field to mix rate positive' field.
      • If your controls surfaces are moving the wrong direction, change the sign (ex. + to -) of the 'mix rate' data

Aura Port Assignments Quick Reference

Verify the servos are installed in Aura correctly (same as factory default)
S1 - Throttle
S2 - Aileron Left
S3 - Aileron Right
S4 - Elevator
S5 - Rudder
S6 - Flap Left
S7 - Flap Right
S8 - Float Rudder (Steering)

Tip: You can change the Aura Port S8 Source and other settings to act as a glider tow release as an alternative to float steering!