Stealth in iF22
by Len "Viking1" Hjalmarson
The Lockheed-Martin F22 is the USAF next generation air-to-air platform. It combines some of the best features of the F15 Strike Eagle and the F117A Stealth Fighter. The F22 meets the USAFs need for an aircraft with long-range, supersonic cruise as well as first-look, first-kill capability.
iF22 simulates this latest development in air defense technology, and combines a dynamic campaign/mission generation system with photorealistic terrain and realistic avionics and flight modelling.
The iF22 is unlike any other air platform out there, and as such the simulation itself is unique, involving unusual tactics revolving around the features of the F22 itself, specifically, stealth technology and the IFDL (In Flight Data Link).
Lets talk about the various sensing technologies and stealth factors in the sim. Areas for consideration include:
- Radar Emissions and Reflections
- IR Emissions
- Detection via Sound and Sight
- Radio Emissions
- Defensive Stealth
Radar Emissions and Reflections
Active radar is NOT the preferable sensing option of the F22. Any time you use active radar you will broadcast your position to even radar receiver within 240 miles (for 60 degrees on either side of your nose).
Consequently, radar should NOT be used when stealth is necessary, and then only as briefly as possible. If you must use active radar, change your altitude and direction immediately after shutting down the radar so that any fighters vectoring to your position will find only empty space.
Radar reflections are another factor. The F22 pilot must take three issues into account here: proximity and position relative to active radar senders; his own stealth state (external stores and weapon bay doors); and use of countermeasures.
First, proximity and position relative to hostile radars. Whenever possible the pilot should approach a hostile aircraft with a low AOT (angle off the tail). The ideal AOT is between 0 and 90 degrees. This minimizes the probability of detection by hostile radar.
Similarly, whenever possible the pilot should remain outside the effective range of ground based EWR and SAM radars. This requires flight path planning (see section five below) and in flight use of the defense MFD mode (see the manual p.72).
Next, external stores compromise stealth by increasing the RCS (radar cross section) of the F22 dramatically. Whenever possible the pilot should limit his ordnance to internal stores. If it becomes necessary to carry external stores they should be used at the earliest possible opportunity or jettisoned if the pilot is under intense radar scrutiny.
The weapon bay doors on the F22 also increase the RCS of the aircraft whenever they are in the open position. The doors should remain in the closed position except when launching internal mounted weapons such as the AIM 9M and AIM 9X.
Proximity to active radars increases probability of detection as distance decreases. As a result the pilot should detour around active sources whenever possible. Increased altitude is generally desirable.
Finally, countermeasures greatly increase visibility to active and passive sources. ECM (electronic countermeasures) are by far the worst offender since ECM actually captures signals directed at the aircraft and, after a varying time delay, transmits them back to the source. ECM, as an active radar, compromises stealth.
In the same way chaff compromises stealth. By providing a large radar cross section near to your aircraft chaff can fool incoming radar missiles, but if you are the target of EWR or SAM radars it also broadcasts your presence to waiting observers.
The primary considerations in infra-red signatures are: use of afterburner, high "g" maneuvers, and use of flares. As with radar cross section, proximity to IR sensing equipment is also a factor.
Use of afterburner should always be avoided when in proximity to IR sensing equipment. Not only does fuel consumption roughly triple, the range at which detection equipment can both confirm your presence and gain a lock increases dramatically. Since "speed is life" and most pilots use ab when they have bled speed unwisely in high "g" maneuvers, remember to conserve energy unless necessary for survival.
A less obvious consideration for IR signatures are speed and high "g"" maneuvers themselves. As your g load increases, so does the friction on the skin of the aircraft and thus your IR signature. In the same way, pulling high g maneuvers not only compromises your energy state, it also increases friction and thus your IR signature and visibility to waiting receivers.
Proximity to IR sensors increases probability of detection. Whenever possible the pilot should approach hostiles from 0 to 90 degrees AOT and maintain a high altitude (30,000 feet or better). Remember that IR missiles launched from 0 to 90 degrees off your own tail will NOT be detected until it is too late.
Finally, use of flares, as use of chaff, compromises stealth by placing a large and hot object in the sky. Use them with due caution.
Detection by Sound and Optics
Next generation fighter aircraft have a remarkably small profile, but their engines produce a considerable amount of noise. Obviously, this is not af actor in detection by hostile aircraft. However, if you are flying below 25,000 feet, your aircraft is detectable by both sound and sight and thus vulnerable to SAMs and AAA.
The Mk 1 eyeball is also a good instrument for detection when you are not at high altitude. Minimizing a visible cross section in the air means flying high.
The Mk 1 eyeball is also useful to the F22 pilot. "First sight, first kill." Keep your eyes open and regularly scan the immediate airspace, especially at your six oclock and especially when no IFDL link is available. If you are the first to see your enemy, your tactical options will be far more attractive.
Finally, whenever possible use the sun to your advantage. A pilot approaching his target from 0 to 90 degrees AOT and out of the sun is virtually undetectable.
Radio emissions are often neglected in discussions of stealth. Pilots should minimize use of radio when stealth is a priority, especially when near to or in hostile air space.
When radio transmissions become necessary for self defense or flight coordination, they should at all times be kept as brief as possible, preferably under five seconds. If you are in a knife fight stealth is not a great issue, though it can become an issue very quickly after your success since other fighters will likely rally to the calls of their comrades.
Defensive Stealth, Mission Planning and the Stealth MFD
"Stealth begins at home." Lt. Col. James Dobson
Okay, I confess, I made that up! But its mostly true...
Stealth considerations begin at the mission planning stage. How important a factor is stealth to the success of your mission? At higher difficulty levels (read, "increased realism") your survival rate will drop the more you compromise stealth.
Use the stealth scale in the payload screen to help you plan your mission. In the same way, use the SAM and EWR intelligence and detection ranges as shown on the planning map to determine your best route to target. Remember to adjust detection ranges by clicking on the altitude scale on the planner. For deep strike missions avoidance of EWR and SAM placements becomes more critical.
If you are flying an Escort mission you will not have control of your waypoints, so its a good idea to cross-check the planning map by adjusting detection range of enemy sensing equipment by the type of aircraft you are escorting. You will be amazed, for example, at how much further EWR coverage will be a factor for a flight of F-15s! This means that you may encounter fighters vectored to your airspace soon after crossing into detection range of your escorted aircraft.
If you are planning a multi-aircraft mission, adjust your formation according to the need for stealth. Three formations are more stealthy than others: the VIC, the Ladder, and the H stack.
Should it become necessary to launch weapons, distance yourself from the launch point by changing direction. Since the launch itself increases detectability by attracting attention to your airspace, changing direction and/or altitude will reduce the likelihood of an intercept.
The Stealth MFD is a useful tool for monitoring your status. Use it to learn about stealth in different states. Check out the iF22 manual for information on using your stealth MFD.
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Last Updated August 30th, 1997