Page 1 of 1


PostPosted: 14 Oct 2009 16:35


As I sit here and stare at the blank sheet to write the story of the LJX... the deeper issue is "where to begin".. There is so much story to the advent of the LJX that it's hard to pick any part or point to start at.

The LJX, traces it's origins to the original Bill Lear Learfan, and Gates Learjet 25C. More particularly, my LFX, a modern incarnation and my original design based on and inspired by the original Learfan, serves as the source for the new LJX. The LFX (Learfan-X), in my opinion, is the sweet spot for every facet that a pilot could want (in a recip prop). I designed it, pencil on paper, such that everything from it's size and proportion to it's interior format would be 'just right'. Not too big, not too small, ample size without being oversized, with clean lines, efficiency, power, and power in spades. It though was tuned to the range of the envelope that propeller aircraft are able to fly in, so it suits operating in ends of the envelope that jets cannot.

So, enter the jet component. Truth be told.. I had been entertaining the notion of doing a real Learjet 23 to satisfy my desire for the smallest, most personal, high performance, GA class "Learjet". I found though that I was running into issues that caused a problem for the logistics of the project. First being.. I already have a Learjet 25C, so to do a 23 would be just plain redundant. To do a 23 would mean killing off the 25 as it would be an unwelcome prospect to develop and maintain both, which by numbers are so similar that only one should be chosen to further or produce. I have books and data materials for the 25... not for the 23. Meaning I should keep the 25 as the real model and..... do what, do the 23 as a custom spinnoff. That didn't fare well with the MU-2B-EVO... everyone kept nagging me for the 2B-40 and failing to really embrace the custom tuner version of the aircraft of the same name, so .. I won't do that again. It'd have to be a real 23 or none at all. Additionally, I found a thread at org where someone else was looking like they were going to do a 23.. and as usual.. when I do one, and when someone else does one.. at best it halves the potential for support that furthers the project with the "...but I can get that one for free" syndrome. So.. dead is the "23" here.

But... my custom designs, "AADX" designed items are just downright locked down, air tight, and I enjoy every freedom to do them exactly as I can imagine, as I feel, as I see, and as I devise. From panel to paint. There's no mystery that my LFX is my favorite and most prized design. It's roots in stated reverence to such an awesome predecessor design, and it's current execution in a way that pushes every button and satisfies every facet of a modern pilots needs.... enter... the Jet variant.

Learjet-X, "LJX" is a direct variant of the "LFX". It shares the entirety of the fuselage, main wings, landing gear, cockpit, and interior with the proven "LFX". The water cooled gasoline turbocharged rotary wankel engine, transmission and somewhat heavy propeller & hub removed. Using the existing LFX fuselage, an aerodynamic body form tail cone installed where the prop & spinner were previously. Through the engine compartment aft of the firewall, and largely using the same reinforced engine mounts, the crossmember to pylons and twin external PW600 series jet engines. The tail had to change from the V.. or should I say "Y" configuration to accommodate the twin side mounted jets, into a more lear-like T tail. I entirely chose the planform for the vstab and hstab of the T tail by eye to fit the proportions, lines, scale and style of the LX design. I feel it again pays reverence to the legacy of the Learjet T tail, while being new and my vision for the design. Similarly, at the main wing.. the planform is retained from the LFX, but the airfoil and incidence twist are wholly different. For the LJX also gone are the winglets from the base design.. which will provide for owner optional blunt, winglet, or extra fuel tip-tanks. The changes to the main wing make it very clean, very lean, and very tuned for high speed, while only at a cost of raising minimum speeds ≤5 knots.. Changing from a gasoline driven propeller single, to a twinjet... the cockpit gauges had to change to accommodate. The whole panel and cockpit environment have a proven consistency and ergonomic form factor, so the whole cockpit area is the same from the LFX with noticeable changes to gauges and systems. More on that I suppose may be written in the production notes file. At the time of this writing, the systems switch panel had yet to be replaced with one for twinjet systems switches, do watch for that in coming versions.

"LJX" expands upon the proven, popular, reliable, consistent and just simply favorite "LFX" design. It expands upon the flight envelope into the jet range, while sacraficing envelope range down into the propeller region. The LJX has a tuned cruise of approximately 250 KIAS, and a Vne of 360 KIAS. Depending on altitude and effort you apply to the engines, true airspeed/groundspeed numbers coming in are in excess of 500 KTAS. Approach speed is "as you wish"... can be slow GA pattern 90, or you can slink in with the airliners clipping along at 140-160 on a long approach corridor. Touchdown speed can be a fly on 90-100 with partial flap and armed speedbrake spoilers.. or can be a full flap small muni field ~65-70 knots. The LJX, along with many other AADX items all feature the most modern, ergonomic, assistive, and automatic systems. You can run complex flights, or hop in like you would your sports sedan. The spacioius 4 place interior leaves room for comfort, and not being crammed into an airplane like a sardine the way most any other aircraft would put 6 in there.. LFX/LJX has 4 with ample spare room for stretching out, moving around, or just simply not being cramped.

I will add here, briefly.. that a small line of liveries was commissioned by "the Agency" for use on special operations missions (see the Flight Operation section). These are for your use as a civilian private contractor to use while taking on some .. missions... that may require such themed liveries. Aside from that.. the Blue and Bronze paints are my personal favorites, the factory white is a blank canvas should anyone care to try a paint design (required to show me first before showing otherwise publicly), and there's even a rather random AT (AirTractor) livery.. (I do live in farmland...) More liveries may be done at some time such as an air-ambulance, courier, or a little more specific charter or mission themed. But I like these and are a good assortment to start with and enjoy. While speaking of liveries.. there is a special treat to see with them while it's dark, so don't be afraid to fly into the evening, or morning.. as the paints have LIT treatment, and the interior has 3d-lighting.

One question I know you may be asking is why "XVII"? Well.. long gone past is the "v8" format or saving anything that will work in v8.. so 8X doesn't really mean right now, for me, what it used to. That is where I deviated from 8X and relabled the LFX that is acf bodied, IIX (8), versus the obj bodied IX (9). The initial LJX is, and is entirely safe and comfortable as an acf bodied aircraft as of X-Plane 9.30 with the per-pixel-lighting that makes the body shine the same as obj bodied planes that prior to 930 were the only ones that had such a fine specular look. Now 930+, acf bodies enjoy the same fine specular light reflections that obj bodies appear like, so an acf bodied aircraft is both fast to make, and can look GREAT. That though can be still directly related to texture richness and quality, so I really chose to make the acf texture such that it took 3d texture baking and shading the same as an obj paint would.. and I think the results are fantastic. Soo. on to the "17" .. XVII.. well.. since the aircraft is rooted in the LFX which already has OBJ fuselage, wings, wingtip options, already ready landing gear, gear doors, and dozens of paints that already serve it... the LJX will be "BOTH" an acf bodied IIX and obj bodied IX in one. My plan, if al goes to plan.. is that both acf files will reside in the same folder using the same common resources for cockpit-resources, cockpit-object, sounds, text files, etc. just like LFX8 & LFX9 are separate acfs, so will LJX8 & LJX9, but in this case, they will be in the same folder to use the same common resources, while the acf's use different objs, they can actually use the same liveries folder for which one is using which content. 8+9=17.. XVII. And mind you.. 8 doesn't mean xplane 8, and 9 currently is synonymous with x-pane 9, but it's anyones guess how long v9 will continue. 9.6? 9.7? If I had roulette style money to put a bet on.. I'd say 9.6.. but at the rate things are going between 9.30 to 9.40.. it may still be another year or two before point six is reached, so don't worry.

Okay.. I'll paste here info from the production notes / poh file so you can get a peek at the type of speeds and performance to expect with LJX. The rest of what there is to know and see are in the pictures, interior, cockpit, and the shakedown video. Ah, the shakedown video. It's not a pleasure ride unless you're into screaming thrill rides. It's not the way the plane is intended to be flown, but it does demonstrate the stability after excessive and exaggerated departures from controlled flight. In short, if it recovers from what I do with it.. anyone can recover from just about any flight condition you happen to errantly get into.


Production Notes:

Vx/Vy: 140KIAS
Service Ceiling : 42,000
Rated Ceiling : 40,000

Recommended climb mode: IAS-AP 140-250

Recommended Speeds:

Vr: 90+
Vy: 135
Cruise Climb: 180
Vg: 140
Vfe: ~140
Vle: ~200
Descent (over 10.0) 220-250
Descent (under 10.0) 180-250
Vs0 : 65
Vs1 : 75
Va : 180
Vno : 250
Vne : 360
Mmo: 0.85
Normal Category G Limits

Engine Failure casualty.
- Any emergency landing prescribes gear DOWN, for all hard & semi-hard surfaces
- Only conditions prescribed for gear UP emergency landing is water, sand or deep crops.


PostPosted: 01 Apr 2012 03:34