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The AT-9 Fledgling on display in the SPH.
- I made sure to include the
aka
in the craft name since, although Curtiss-Wright named it theFledgling,
this plane was more commonly known as theJeep
in the United States Army Air Forces. - I used a fairing to mimic the real-life nose cone as close as I could; not too long, and yet with a pointier end than the aerodynamic nose cone.
- Due to the relative propeller length on the real-life Jeep, I figured I could get away with R-25 ducted fan blades on the gas-powered engines.
- For the R121 engines, I reduced their motor size to 50%.
Though it proved more fuel-efficient than 100%, I don’t know if I should have reduced it some more. For that matter, does the total thrust-to-weight ratio even need to be over 1?
- Finding a good spot and orientation for the ladder proved more difficult than I thought, as the pilot often had trouble getting to and from the cockpit in test runs.
Jeb (the Third) doing a barrel roll over the KSC right after taking off as part of his Air Force pilot’s training.
- Unlike back on Earth, Kerbin’s Air Force kept using this as the primary
transition trainer
after the Second Imperial Wars. Any airmen seeking to get cleared to fly multi-engine aircraft had to complete the necessary training in the Jeep. And then, they could move on to training in multi-engine jets. - The Kerbal Space Program, however, didn’t have multi-engine prop trainers. In fact, after its early years, it didn’t have prop-powered anything outside of those used for airshows - or old planes the KSP’s pilots were hired to test fly.
Jeb clearing Alt Test Mountains at a cruising altitude of 7 km.
Real-life Counterpart Performance Stats
(AT-9 Fledgling)
Maximum Speed: 197 mph (88 m/s)
- Cruise Speed: 173 mph (77.3 m/s)
Service Ceiling: 19,000 feet (5.8 km)
Range: 750 miles (1,207 km)
Source: Air Force Museum Website
Details
- Type: SPH
- Class: aircraft
- Part Count: 63
- Pure Stock
- KSP: 1.12.4
Description
The Curtiss-Wright AT-9 Fledgling, which was more famously known as the “Jeep,” was a trainer aircraft used by the United States during WWII to bridge the gap between single-engine trainers and twin-engine combat aircraft. The first prototype flew in 1941, and the production version entered service in 1942. The Jeep was intentionally designed to be less stable and proved to be difficult to fly or land, making it suitable for teaching new pilots to cops with the demanding flight characteristics of a new generation of high-performance, multi-engine aircraft. Because of said difficult flying characteristics, the Jeep was not offered for sale to civilians after the war – but many non-flying examples were given to ground schools for training purposes.
A stock aircraft called Curtiss AT-9 Fledgling (aka Jeep). Built with 63 of the finest parts, its root part is Mark2Cockpit.
Built in the SPH in KSP version 1.12.4.
Another neat shot of Jeb flying the Jeep, this time over the desert. He logged that, to increase fuel efficiency while maintaining speed, he had to gradually ease the throttle back during the course of the flight.
Noticing he was running low on fuel while going over water, Jeb decided to turn north for the remainder of the flight. After it reached critical levels, he aimed for a flat spot in the desert and began his landing.
Takeoff Instructions
- Engage the brakes and turn on SAS.
- Full throttle.
- Disengage brakes.
- Press and hold H (translate forward). It increases the propeller blade deploy angle - hence your speed.
- Retract gear when airborne.
- Keep tapping H as necessary to keep optimal blade angle (which maximizes thrust). It is recommended to tap rather than press and hold for fine-turning blade angle. Best blade angle for maximizing thrust is 45 degrees, but you do what works best for you.
Be advised that you may need to slowly lower blade angle again at some point. When that happens, translate back using N.
Jeb stepping out of the Jeep after a range test. According to his mission report, landing was harder than it looked due to the plane’s tendency to keep its tailwheel off the ground.
- His father’s friend, Bill Kerman, did warn him beforehand that the Jeep was designed to be hard to land.
Propeller Controls
- H: Translate forward (increase blade angle)
- N: Translate backward (decrease blade angle)
Landing Advice
After you land the plane, (unless you’re all done with it) press and hold N to return the blade angles back to 0 before taking off again.
RECOMMENDED CRUISE
Altitude: 7 km (~23.0k ft; Class Alpha airspace)
Velocity: 230 m/s (~514.5 mph)
Blade Deployment Angle: 42 degrees
- 45 degrees is optimal
Recommended Throttle:
- ½ at the beginning
- Gradually decrease during flight to maintain airspeed while maximizing fuel efficiency
- Slightly under 1/3 at the end
EXPECTED RANGE
500 km before immediate landing necessary.
