Operation of the
DISS-15 Doppler Navigation Set
by (C/229) Strut -17 July2014

1.In this lesson you are going to be taught the operation and use of the DISS-15 Doppler Navigation Set. (Using the Leg Based System only)

2.The reason you will be taught this is that you as a pilot operating the MI-8 MTV Helicopter will be required to navigate your helicopter. You will be required to know geographically where you are at all times and not become geographically embarrassed (in other words lost ).

3.At the end of this lesson you will:a. Be able to plan your route to your first way-point using the Leg Based System,

b.Set up the Doppler and peripheral equipment to operate, and

c.Understand how to use the Doppler to navigate.

Stationary Flight Indicator

Ground-speed Drift Indicator

Doppler DigitalDisplay

Note:The Doppler Control Panel is located behind the Co-Pilots Rightshoulder on the bulkhead.

Mission Prep

1. Ensure your In-Game DCS settings are set to metric, the Doppler uses km. There are two methods used to operate the Doppler:a. Leg Based Method, andb. Great Circle Navigation Method.2.For this lesson we will only use the Leg Based Method of Navigation. Great Circle Navigation is more complex and will be taught at a later time and is more appropriate to long distance flights and navigating in difficult conditions.3. Plan your route example > mission requires direct or indirect routes to destination. Avoiding known ground fire , weather or high terrain. Friendly FARPs, Fuel resup points etc.4. The Doppler can only be fed 1 route or waypoint at a time so multiple way-points will need to be imputed as you fly. So make a basic Nav data sheet for reference during flight, number your way-points and using the ruler function in the F10 map carefully measure bearings and distance for each one. Once you have your bearings, convert the bearings to magnetic bearings by subtracting the Mag variation of 6 degrees for the DCS map.5. For Example:Waypoint Bearing DistanceRemarks01217'37kmRemain below 200ft, Right turn to WP 202305'76 kmStormy weather from S/W , avoid built up areas.If you want to be more detailed you can add more info as you like, more info the better. For example ETA, estimated or intended cruising speeds etc etc.

Description and Characteristics of the DISS-15 Doppler Navigation Set

1.The Doppler system (DISS-15) is designed for continuous automatic measurement and display of the ground speed in the following components:a.In the low speed (hover) mode;b.In ground speed and drift angle in the navigation mode; c.In computation and indication of the helicopter positional coordinates (Great Circle Nav); d.and for delivery of these data to other onboard systems.

2.The Doppler system consists of: a.a high frequency unit, b.a low frequency unit,c.a coordinates computer, d.the Stationary Flight Indicator located on the pilot's instrument panel, e.the Ground Speed/Drift Angle Indicator located on the copilot's instrument panel,f.the Doppler Digital Display Unit located on the copilot's instrument panel, and g.the Doppler Control/Test Panel located on the right rack in the cockpit.

3.The Doppler system, in conjunction with other onboard instruments (i.e., autopilot, radar altimeter, etc.) assists the pilot in solving the following navigational and flight problems: a. Precision approaches,b. Hovering and landing,c. Hovering and controlling helicopter movement in poor visibility or Instrument meteorological conditions (IMC).

Doppler Control Panel and Right Triangular Panel

1.The Doppler control panel is used to select the operating mode of the system and to introduce three test problems. For Leg based System of Navigation the system is turned off, no lights will be illuminated on the panel.

2.For Great Circle Navigation the system is turned to Memory. There are 3 settings for self diagnostic tests to ensure the control panel is working. The figures at each setting will show on the Doppler Digital Display to prove/disprove the DISS is serviceable. .

Off Position

Doppler Control Panel

Right Triangular Panel

3.This control module is used in the Start Up process during which the DOPP is turned on.The 5.5v Lights(DOPPLER SYS) should also be turned on.

The Doppler Digital Display and Ground Speed/Drift Angle Indicator

2.The digital display unit displays the distance the helicopter has flown from the starting point and the lateral distance to the left or right of the course that the pilot enters on the COURSE ANGLE counter. The readout information is provided by the Doppler computer.

1.The ground speed/drift angle indicatordisplays the ground speed in KM/H and drift angles in degrees when the helicopter is travelling at speeds in excess of 50 KPH (27 knots).

The Stationary Flight Indicator

The stationary flight indicator continuously displays the vertical, lateral, and longitudinal components of helicopter ground speed during hover and low speed flight, the bars inside the Indicator will light up and indicate movement. The side scale indicates movement up or down in meters per sec. During a hover it is not recommended to descend faster that 2 meters a sec when at low altitude.

Operation

Step 1 Ensure the DOPP and 5.5v Lights (Doppler SYS) are on in the Right Triangle Panel.

Step 2After tests (not compulsory in sim)ensure switch is at off position, lights will be out.

Step 3Using - / + input bearing, round off the minutes to wholeDegrees.

Step 4Either using AFT set your distance to count back from your WP or keep on 000 to count up to your WP.

Step 5Turn on ENABLE will light up.

Operation -cont

1.The Doppler is now set, ensure that your course is set on the compasses of both the Pilots and Co-Pilots course indicators to the same bearing as the Doppler. You still need to read off that to give direction for your heading.

2There is NO more to it , the Pilot will use his compass to keep his heading, the co-pilot will observe the Doppler Digital Display for distance/ direction and Ground Speed/Drift Angle Indicator to help adjust for wind on your route to bring you back on course. (Obviously because we don't have a real Co-Pilot you will do it all)

3. Also this thing doesn't fly the aircraft or control it in any way. And ensure you keep reading your map. All the best gadgets in the world are still only aids to navigation.

Conclusion

In this lesson you have been taught the DISS 15 Doppler Nav Set. As seen, the procedure is simple and is fast to set up. The system is designed to assist you in all modes of flight and navigation for the safe operation of the aircraft.

Practice the procedure and it will be easy to remember after a couple of run throughs.

END OF LESSON

Good luck From (C/229) Strut

Conclusion

In this lesson you have been taught the DISS 15 Doppler Nav Set. As seen, the procedure is simple and is fast to set up. The system is designed to assist you in all modes of flight and navigation for the safe operation of the aircraft.

Practice the procedure and it will be easy to remember after a couple of run throughs.

END OF LESSON

Good luck From (C/229) Strut