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Screen shots by Xtreme Prototypes |
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Extreme Prototypes' 20 Series Business Jets is a collection of three Gates Learjets: Models 24, 25, and 28. The Model 23 Learjet and Model 29 Gates Learjet are not included in this package.
Model 24: This was an improved version of the original Model 23 Learjet with higher gross weight, higher ceiling, more powerful engines, and additional passenger windows among other improvements. It was the first business jet certified under FAR-25 Airworthiness Standards.
Model 25: A stretched version of the Model 24, this model holds up to ten persons and has a customizable cabin.
Model 28: This model has winglets instead of tip tanks, which give it higher efficiency and fuel economy. Some sources say it has longer-range fuel tanks, but ranges I found for this model are lower than those for Models 24 and 25. Lower ranges make sense because it has no tip tanks.
Model 23 was built by Bill Lear in 1963 based on a Swiss design for a fighter jet. Designers had no idea their creation would evolve into the one of the world's better known private jet aircraft.
Learjets are so common that they have appeared in numerous motion pictures and been involved in many aviation incidents over the last five decades. As two examples: Inventor Bill Lear played a Learjet pilot in the 1967 movie In Like Flint with James Coburn according to the Internet Movie Data Base. In 1999, professional golfer Payne Stewart died while traveling in a Learjet 35 that depressurized at high altitude and flew on autopilot from Florida to South Dakota where it ran out of fuel and crashed. That particular aircraft had several maintenance activities regarding pressurization in the months leading to the incident.
This aircraft is only for FSX. It is compatible with FSX Acceleration, SP2, and FSX Deluxe, but those special programs are not required.
Purchase and installation from the Pilot Shop are very easy. Downloading takes a few minutes. Installing takes about one minute. A license key and legal agreement are required. The installation program installs all the aircraft-related files into the "C:\Program Files\Microsoft Games\Microsoft Flight Simulator X\SimObjects\Airplanes" folder and the manuals, paint kit, and uninstall program into the "C:\Program Files\Xtreme Prototypes" folder.
Sounds are not borrowed from the MSFS default Learjet. The sound folder includes 17 sound files that sound like the MSFS default Learjet, however.
Removing the product (if desired) is easily done with a handy uninstall program.
Technical support is available through the developer's website.
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PURCHASE FEATURES |
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Instant download from the Pilot Shop |
Yes |
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Installation program |
Yes |
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License key required |
Yes |
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Copyright acknowledgment required |
Yes |
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Manual included |
Yes |
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Checklists & reference included |
Yes |
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Uninstall program included |
Yes |
Xtreme Prototypes lists these among other features of its 20 Series Business Jets:
All three models are visually accurate inside and out compared with plentiful photos I found on the Internet. Dimensions and unique features of each model are all realistic. Details seen close up give the aircraft realistic appearances.
Cockpits, panels, and cabins for all three aircraft are identical. They are basically consistent with interior photos I found on the Internet. Whether original interiors for all three real-world models were identical I cannot answer. All three cabins are well presented and occupied by an animated young women sitting at a table holding a drink.
The main instrument panel features a built-in GPS device. This could be added to real Learjet panels later if space allowed, but it is not true to the period because civilian GPS did not exist when these aircraft were developed and built in the 1960s and 1970s. There is no 2D panel. Some flight simmers like them, and some don't use them. There is one popup window for a GPS device. There are no popups for radios or throttles as is common in default MSFS aircraft.
Setting knobs for instruments such as the heading bug, altimeter, and radio frequencies operate with the mouse wheel instead of the left and right mouse clicks as is conventional in MSFS.
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SAMPLE PAINT SCHEMES
Three of Seven Models | ||||||||||
Aircraft-Selection Menu
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Model 24
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Model 25
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Model 28
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Screen shots by Bill Stack | ||||||
| VISUAL DETAILS | |||||
Exterior Surfaces
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Wheels & Wells
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Shape
| Screen shot by Bill Stack | ||
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COCKPIT, CABIN & PANELS OF EXTREME PROTOTYPES' LEARJETS | ||
Cockpit left |
Cockpit center |
Cockpit right |
Panel Details |
Console |
Panel, Lighted |
Cabin |
Cabin |
Cabin |
| Screen shots by Bill Stack | ||
Performance specifications vary with the numerous submodel types such as 24B, 24C, and 24D. The following specifications are taken from Xtreme Prototypes' manual, reference sheets, and aircraft descriptions.
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AIRCRAFT SPECIFICATIONS
From Xtreme Prototypes | |||
| Model | 24 | 25 | 28 |
| Empty weight | 7,064 LBS | 8,121 LBS | 8,568 LBS |
| Maximum take-off weight | 13,500 LBS | 15,000 LBS | 15,000 LBS |
| Cruise speed | NA | NA | NA |
| Maximum speed | Mach 0.82 at 24,000 FT | Mach 0.82 at 24,000 FT | Mach 0.82 at 24,000 FT |
| Stall speed | NA | NA | NA |
| Range 1 | 2,000 NM | 2,000 NM | 2,000 NM |
| Ceiling 2 | 51,000 FT | 51,000 FT | 51,000 FT |
| Climb rate | NA | NA | NA |
| Seating | Up to 6 | Up to 8 | Up to 8 |
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Notes:
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For nostalgically realistic test flights, I used Wichita Mid-Continent Airport (KICT) in Wichita, Kansas, U.S.A. Originally named Wichita Municipal Airport, it was Learjet's home base in the 1960s. With elevation of 1,333 feet (406 meters), it has three runways: 1L/19R is 10,301 x 150 feet (3,140 x 46 meters), 1R/19L is 7,301 x 150 feet (2,225 x 46 meters), and 14/32 is 6,301 x 150 feet (1,921 x 46 meters). In all tests, I used the default weights for each model, and I set power levels as recommended in the manual. As usual, I used clear skies and standard atmosphere.
I found similar flight characteristics among all three models:
Taking Off: At 100-percent power as recommended, all three models took off at airspeeds well below those specified in their reference sheets and manual tables. As one example: Model 24 is 133 pounds over its maximum gross weight according to Fuel/Payload menu, yet it took off slower than the specified airspeeds from an airport more than 1,300 feet above mean sea level. It rotated at 90 KTS whereas the reference sheet says rotation speed is 120 to 136 KTS depending on weight. It lifted off between 100 and 110 KTS whereas the reference sheet says the climb speed is 124 to 140 KTS from a dry runway. I assume "climb speed" means "lift-off speed" because runway surface is irrelevant after the aircraft is airborne and climbing.
Climbing: At 90-percent power and 15-percent pitch as recommended, the models climbed out at 160 KTS and 1,500 feet per minute. Later they climbed at 160 KTS, 4,000 feet per minute, and a 15-degree pitch. As they gained airspeed, they easily climbed at 240 KTS, 4,000 FTP, and 20-percent pitch. Between 5,000 feet and 10,000 feet at 90-percent power and 10-percent pitch, they climbed at 180 KTS and 3,000 FPM. Between 10,000 and 15,000 feet and 10-percent pitch, they climbed at 180 KTS and 2,300 FPM.
Above 15,000 feet, they climbed at 175 KTS and 2,000 FPM. The documents say nothing about optimum climb airspeeds or rates for any of the three models.
Straight and Level: All three models handle straight and level flight very easily. No cruising speed is specified. Maximum speed is specified as Mach 0.82 at 24,000 feet. So I leveled off at 24,000 with the engine gauges at 90 percent. Airspeed increased to 381 KIAS. Quick conversion formulas return 563 knots true airspeed and 0.94 Mach. Of course, the overspeed alarm sounded. After I reduced throttle to 80 percent RPM, indicated airspeed went below 300. To get 330 KIAS, I increased power to 87 percent. Mach read 0.74. My Mach calculations corresponded with the Mach indications on the airspeed indicator. Thus, I was unable to get to the Mach 0.82 specified maximum speed without an overspeed warning.
Turning: All models turn easily like other Learjets. They hold their altitudes with just a little pull on the yoke.
Ceiling: None of the models reached the specified cruising altitudes of 45,000 feet or 51,000 feet. With autopilot set to 51,000 feet and power at 80 percent, they started losing indicated and true airspeed around 34,000 feet. Even after throttles were moved to maximum position and power was 90 percent, the aircraft stalled around 40,000 feet. I was unable find a climb rate the aircraft seemed comfortable with.
Descending: With engines at 75-percent power as recommended, all three models descended gracefully between 200 and 300 KIAS (true airspeed and Mach will naturally differ at different altitudes). With throttles all the way down, all three models glided gradually and smoothly. They did not reach stalling speed while descending.
Approaching: No stall speed is specified, and all models stalled around 100 KTS while power was low. Because they don't recovery easily or quickly from stalls, low-altitude stalls in these aircraft result in crashes. Pilots must therefore watch airspeed and pitch very closely throughout all low-speed, low-altitude maneuvers such as landing approaches.
Landing: These aircraft land smoothly at 110 KTS. The reference sheet says landing speed is 110 KTS to 124 KTS, with the heavier speed for higher weights, but all three aircraft landed at 110 KTS while nearly at maximum weight. Without thrust reversers, these aircraft are stopped with spoilers, flaps, and wheel brakes. Landing distances are shown in a table in the manual.
Taxiing: Taxiing is very easy in these aircraft as long as speed is reasonable.
Overall: All three models are easy to fly. Detailed performance data in the manual enable realistic simulations. Disparities between specifications and performance, such as take-off speeds, maximum speeds, and maximum altitudes, raise questions as to whether documents accurately reflect performance or whether performance is as it should be. Having never flown a real-world Learjet, I can only report on the flight characteristics of Xtreme Prototypes' simulation models and not on how they reflect their real-world counterparts.
| EXTREME PROTOTYPES' LEARJETS IN FLIGHT | |
Model 24 |
Model 24 |
Model 24 |
Model 25 |
Model 25 |
Model 25 |
Model 28 |
Model 28 |
| Screen shots by Bill Stack | |
Checklists and reference sheet are available in the manual and in the usual kneeboard popup windows. Both are similar in format to the default MSFS checklists and reference sheets, yet both are obviously customized for these aircraft. The checklists provide detailed steps for preflight, all flight phases, and shutdown. All checklists and reference sheets are identical across the three models.
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CHECKLISTS, REFERENCE SHEET, & POPUPS
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Screen shot by Bill Stack |
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Information about these aircraft is provided in two 84-page manuals — one English and one French, which the installation program installs in this folder: C:\Program Files\Xtreme Prototypes\. Shortcuts are provided in the Start Menu under Program Files.
The manuals explain software installation, aircraft description and specifications, aircraft systems, instrument panels, flight planning, normal operating procedures, emergency procedures, reference information, and technical support. Checklists provide detailed data for preflight, all flight phases, and shutdown, including several tables with various V speeds under various conditions.
Numerous annotated screen shots showing aircraft parts, instruments, and controls. Explanations are concise.
This manual is among the more comprehensive, well-organized, and neatly presented I have reviewed. It reflects considerable attention to quality and is worthwhile by itself. Hats off to developers who invest this much time and effort into explaining how to use their products! I am unable to show examples because it is configured to prevent copying and my requests for examples from the developer went unanswered.
Several special features are included: engine smoke, contrail effects, wing vortices, vapor trails, and a paint kit.
| EXTRA FEATURES | |||||
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Contrails
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Door Open
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Door Open
| Screen shot by Bill Stack | ||
Information about the real Gates Learjets can be found at these websites, among others:
Other products from Xtreme Prototypes include the Avro CF-105 Arrow and the X-15-1.
Xtreme Prototypes' Gates Learjets 24, 25, and 28 are visually very good aircraft. The manual is superb — among the better I have seen. Installation is easy and flawless. Flight handling is basically easy. The inability to reach specified cruising altitude, the inconsistencies among performance specifications, and the conflicts between specifications and performance need correction.
Bill Stack
billstack@flightsim.com
Learn More About Xtreme Prototypes' Gates Learjets 20 Series.
Bill Stack is author of several books about flight simulation, a regular author in flight-sim magazines, and a contributor to Flight Sim Com. His website is www.topskills.com