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In Development : Eagle 315 Twin Prototype by Eagle Flight Labs

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Eagle - 315hp-recip - Header.jpg


In Development : Eagle 315 Twin Prototype by Eagle Flight Labs


Most reviews that come across our simulator are usually based on real world aircraft, a reproduction of a real life machine to practise on, train on or use in a highly realistic way of flying. So you usually look for the reproduction of the real to the simulator, and the way you interact with the machine to mirror the same in the aviation world.


But X-Plane per-se, if you go back to it's basic origins was not created for that reason, replicating the real world machines (but that was the ultimate achieved goal) but the very soul name X-Plane gives it's meaning to it's basic reason to be a simulator. X-Plane is based on the X - Experimental line of aircraft for the "National Advisory Committee for Aeronautics" (NACA) or later NASA and expereimental designs were fielded out to the different manufacturers that got the job of building them (Bell for the X-1, X-1A,B,C,D,E and X2 and Northern American for the X-15) in other words the odd and the weird, but all were created to do a specific job in aviation or space and the full list is here. Anyway it easily beats the Flight Sim foundation that Bill Gates just liked aircraft.


So although X-Plane is now immersed in the constant replication of real world machines, then at it's heart it was actually created for all the tinkerers out there. From the start X-Plane had PlaneMaker (still does) and built in airfoils, with the idea that anyone can create and test fly their own Experimental aircraft with real world dynamics (the famous aerodynamic model called blade element theory), mostly these aircraft are the really weird and wonderful, but mostly all are sadly and usually consigned to the freeware backpages of history. But the innovation and ideas around these projects should not be forgotten or lost. It is important to note that aircraft created out of fantasy is more based on the X-Plane mantra than folklore, the point of these projects are for the developers to understand how aviation and the dynamics all work, plus the fact they can gain skills in recreating aircraft in the highly developed market that we have today...  in other words we all have to start somewhere, the Daniel Klaues, Aerobasks, X-Crafts the FJS Jack Skieczius and all our highly talented developers all started messing around with ideas in the PlaneMaker application, it is our starting school or university of the developer, lose that aspect and then you lose X-Plane in context.


So here is a just an aircraft in the Eagle - 315 Twin Prototype by Eagle Flight Labs. In soul it is a pure X-Plane aircraft, but uses real world specifications, but it is created in a innovative context, yes it looks odd, even weird, but the basic fundamentals of the aerodynamics are also correct and if a real world machine was built it would certainly fly as per this simulation.


Eagle - 315hp-recip - Head 1.jpgEagle - 315hp-recip - Head 2.jpgEagle - 315hp-recip - Head 3.jpgEagle - 315hp-recip - Head 4.jpg


The Eagle is a cross of classic (Pre-WW2) and current dynamics, odd but from an aerodynamic aspect absolutely correct, so this gives you the experience to take something based on classic design and update it, then test the ideas to see if they will conform to the real world specifications, the biggest mistake most early developers do is to create the too much "Flight of Fantasy" sort of ideas, very futuristic in looks but also highly compromised in design and flight aerodynamics, and yes X-Plane does allow you to do that...   but the trick taken here is to, yes be very experimental, but to still keep your specifications in the real world.


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The Eagle is a tandem - two seater, one person behind the other in a fighter jet configuration, interesting because it gives the aircraft a very low frontal area and a fine aspect to the airflow... Power is via two 160 HP (119 kW) engines to an adjustable three blade propeller, gear is three point that is retractable....


Eagle - 315hp-recip - Cockpit 1.jpgEagle - 315hp-recip - Cockpit 2.jpg


....  Cockpit and instrument panel is what I would describe as H.G.Wells in design, white large instruments with a left protruding pod of Throttle/Propeller/Mixture lever, pushpull knob set of controls...  odd yes, but it is surprising how quickly you adapt to the layout. Huge trim knob is easy accessible on the end.


Eagle - 315hp-recip - Cockpit 3.jpg


Instruments are top row: Airspeed, Artificial Horizon (Bubble style), Altitude, NAV 1 VOR CDI for lateral course track, but it also has a built in glideslope indicator. Second row: Turn Coordinator, Horizontal Situation Indicator, Vertical Speed, 2nd VOR CDI.


Lower two rows cover the engine instruments: Manifold Pressure, RPM, Fuel Quantity (47 GAL - Per Left & Right tank), fuel flow 7 -11 GPH per engine (55% - 75%), Battery Charge, Oil Temp, Oil Pressure, Fuel Pressure, EGT (Exhaust Gas Temperature) and Vacuum. A clock and compass are far right.


All the instruments are custom designed, of course it would have been just as easy to have used the X-Plane PlaneMaker default instruments, as they are all there for this application, but custom designs means it not to be an PlaneMaker design.


Right console has top...   Power, External Lighting and Instrument lighting switches. Lower two Bendix/King KX 155  radio units with one for COMM 1/VOR/NAV 1 and the other for COMM 2/NAV/VOR 2


Eagle - 315hp-recip - Cockpit 5.jpgEagle - 315hp-recip - Cockpit 6.jpg


Lower is a Bendix/King KT76A Transponder and a custom S-Tec Autopilot. On the sidewall there is a 24 working active set of circuit breakers (the list is noted on the right side) and they all work as noted. The system is two buses with each one powered by its own battery and engine driven generator. Bus 1 (left) and bus 2 (right) are both independent.


Fuel tank switching is on the left, and note the nice canopy latches...  rudder pedals are custom as well.


Eagle - 315hp-recip - Cockpit 7.jpgEagle - 315hp-recip - Cockpit 8.jpg


There is a 3D VR pop-out clipboard that rotates 180º, but it has poor resolution and is hard to read? 180º rotation? I think for the coming custom load/center of gravity settings.


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Seats are excellent and look very, very comfortable, and so is now the cockpit detailing, as earlier cockpit versions were a bit.... ahem poor, but it looks really well done in here now with all the teak wood grain and detailed sidewall textures.


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Turn off the electrics and magnetos and the aircraft goes into ground mode...  the canopy can opened up the full 100% and chocks go on the wheels and a stored ladder is hung out on the fuselage, the pilots then move external with a baggage cart, and pose like in an aviation advert. Both pilots look undernourished and are heading to a business meeting more than flying an experimental aircraft, but they are well done


Eagle - 315hp-recip - Cockpit 16.jpgEagle - 315hp-recip - Cockpit 17.jpg


Gear looks aluminium, but it is still a WIP as they all look factory fresh, but detail is very good, and an unusual way to connect the wheels to the strut (no hub).


Eagle - 315hp-recip - Cockpit 18.jpgEagle - 315hp-recip - Cockpit 19.jpg


Adjust the aircraft's weight above 2950 lb and an underbody cargo container (per Cessna Caravan) is then attached, it smooths out the aircraft's shape, but it also comes with 6 knt additional drag factor.


Eagle - 315hp-recip - Cockpit 20.jpgEagle - 315hp-recip - Cockpit 21.jpg


Flying the Eagle!

Turn the starter keys and the engines roar into life...  sounds are all FMOD and are actually very good and 180º variable....


Eagle - 315hp-recip - Flying 1.jpgEagle - 315hp-recip - Flying 2.jpg


....  the view out is quite remarkable, more helicopter/glider bubble than a GA.  Aircraft weight is 1900 LB with a max take off weight of 3800 lb.


Eagle - 315hp-recip - Flying 3.jpgEagle - 315hp-recip - Flying 4.jpg


Taxi control is very nice and any throttle positions will be felt if required, in other words if one engine is below par of the other you can even them up with the throttle. Power up and rotate is 80 knts +10 the Vref speeds are noted on the Airspeed dial... 


Eagle - 315hp-recip - Flying 5.jpgEagle - 315hp-recip - Flying 6.jpg


Unusual is the gear arrangement, the front strut is notably very forward, and rotates up into it's own semi-housing pod, the two main wheels retract inwards into the wings...  undercarriage detail is very good and the movement/animations are excellent....


Eagle - 315hp-recip - Flying 7.jpgEagle - 315hp-recip - Flying 8.jpgEagle - 315hp-recip - Flying 9.jpgEagle - 315hp-recip - Flying 11.jpg

Eagle - 315hp-recip - Flying 10.jpg


The Eagle maybe an odd looking critter, but it is simply fantastic to fly...   It is very easy to trim out and then the aircraft is very nicely balanced in your hands.


Eagle - 315hp-recip - Flying 14.jpgEagle - 315hp-recip - Flying 15.jpg


The unusual Horizontal Situation Indicator is really like a flat compass, so you adjust the heading to the compass degree (arrowed) and then follow the needle


Eagle - 315hp-recip - Flying 16.jpgEagle - 315hp-recip - Flying 17.jpg


...  like everything you get used to it easily. In the air the Eagle doesn't feel like an experimental aircraft, but highly realistic....  so this isn't a cheaply made up PlaneMaker freeware machine, as this is something altogether different.


Eagle - 315hp-recip - Flying 19.jpgEagle - 315hp-recip - Flying 20.jpgEagle - 315hp-recip - Flying 21 LG.jpg


You have to sort of experience the aircraft to love it, but the flying and control is excellent and it all feels very real world. Average cruise speed is 180 kt TAS,, and MAX cruise is around 195 kt TAS, 13,500 ft is the ceiling (non-pressurised) and the range is around 900 Nm.


S-Tec autopilot is very easy to use and versatile, built in FD (Flight Director) and YD (Yaw Damper) are bonuses, Transponder though is hard to see/use with the canopy boundries.


Eagle - 315hp-recip - Flying 18.jpgEagle - 315hp-recip - Flying 21.jpg


Powering along the coast you could easily sit up here all day, even with the autopilot off and everything nicely trimmed you just drift along....


Eagle - 315hp-recip - Flying 13.jpgEagle - 315hp-recip - Flying 12.jpg


...  low speed control is also excellent, once under 100 kts then flaps 2 is around 85 kts with speed bugs that do change for the best performance....


Eagle - 315hp-recip - Flying 22.jpgEagle - 315hp-recip - Flying 23.jpgEagle - 315hp-recip - Flying 24 LG.jpg


...  full flap (3) is 75 kts... (note flaps are four settings and not three or 0 - 1 -2 - 3 with 0 being retracted and 3 Full, when the flaps are extended they sit out and away from the wings which looks great. All flap and weight speeds are noted in the manual.


Eagle - 315hp-recip - Flying 25.jpgEagle - 315hp-recip - Flying 26.jpg


Reduce the power gradually to 68 kts and lift the nose slightly higher and the Eagle will land nicer than Neil Armstrong did on the moon 50 Years ago, perfect control with lift and fall just a throttle adjustment away....  stall is noted at around 56 knts.


Eagle - 315hp-recip - Flying 27.jpgEagle - 315hp-recip - Flying 28.jpg


You do have to be still aware of those long spindly legs though of the gear, as you do sit high and not close to the ground.


Eagle - 315hp-recip - Flying 29 LG.jpg



The white dials glow in the dark with full adjustment, it looks nice and is also easy on the eyes and weirdly it looks authentic...


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....  a single overhead red spot will light up the switch panel. Externally it is pretty basic, with navigation and strobe lights, there are no taxi lights, but just landing lights at each tip of the wing.


Eagle - 315hp-recip - Lighting 5 LG.jpg



There are two liveries the default "Eagle" and another one called "Fire Particles!"


Eagle - 315hp-recip - Livery Eagle.jpgEagle - 315hp-recip - Livery Fire Particles.jpg



This is a project that is a WIP, and a sort of VSkyLabs involvement.... but the Eagle also goes very much into the core of what X-Plane as a simulator is all about. This aspect allows you to create and test an experimental aircraft to see if such a design would fly and correctly operate in real world conditions.

The trick here is not to do a "Flight of Fantasy" but to use real world data to create a real working design...


Yes it looks unorthodox and even a bit weird, and bit of Pre-WW2 or single-engined twin post war trainer, but overall the aircraft flies extremely well, even my first reactions were very positive and the flying doesn't leave you quickly in that you enjoy the experience... and that is the whole point of the Eagle.


Projects like this need positive encouragement, as developers with far less talent have gone on to do extraordinary things in X-Plane, it is in the details and the ideas in the Eagle that makes it interesting, but also the sheer learning curve that is required to turn out quality aircraft now in X-Plane, we all have to start somewhere... but talent is talent and it is in aircraft like the Eagle that you can see that talent emerging... I saw a very early rendition of the Eagle, the fundamentals were correct but it needed a lot more design work in many areas, here you can see all those elements that are now coming together, and yes the Eagle is only a stepping stone, but an interesting one... but overall with the Eagle you can go back to real foundation of what X-Plane as a simulator stands for i experimental and for what its true core is all about.


You can support the Eagle project by purchasing the aircraft via the Eagle Flight site it is priced currently at US$12.50...  if demand is acceptable it may be also released on the X-Plane.OrgStore...






Eagle twin 315 HP prototype


Priced at US$12.50


Features :

  • Full featured model and 3D cockpit
  • Custom S-Tec avionics
  • Custom systems
  • Fuse and failure panel with 24 items
  • Cargo bay under the fuselage (custom load/center of gravity will be managed by plugin in late development updates)
  • Custom 3D sound environment




Basic PlaneMaker design is very light on requirements, so even a very light GPU can run this aircraft.

Current version and Review Version 1.0 (May 30th 2019)


Installation and documents:

Download for the Eagle is 388.90 Mb and the unzipped file is deposited in the aircraft "General Aircraft" X-Plane folder at 370.90 mb.



Basic manual but with performance details required and Checklist.


  • Check_List - EN
  • Manual - EN



Aircraft Review by Stephen Dutton 

30th May 2019

Copyright©2019 : X-Plane Reviews 


(Disclaimer. All images and text in this preview are the work and property of X-PlaneReviews, no sharing or copy of the content is allowed without consent from the author as per copyright conditions)


Review System Specifications: 

Computer System: Windows  - Intel Core i7 6700K CPU 4.00GHz / 64bit - 16 Gb single 1067 Mhz DDR4 2133 - ASUS GeForce GTX 1080 8Gb - Samsung Evo 512gb SSD 

Software:   - Windows 10 - X-Plane 11.31 (v11.30 is required for this aircraft)

Addons: Saitek x56 Rhino Pro system Joystick and Throttle : Sound - Bose  Soundlink Mini

Plugins: Environment Engine by xEnviro US$69.90 : WorldTraffic 3.0 Plugin - US$29.95

Scenery or Aircraft

- KRSW - Southwest Florida International Airport by Aerosoft (X-Plane.OrgStore) US$24.99

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Good day,


As far as my understanding is, the PA-23 might have be designed with a certain max normal cruise speed lying in the region of 150 kt.


Given what seems saying the airfoil, past below alpha zero degree, the drag coeficient 'jumps', hence it would be difficult to accelerate beyond this IAS (flight characteristics rapidly decreasing above).


The Eagle aircraft is based on a simple airfoil NACA 2412, I checked its L/D is 9.0 at max cruise, which is relatively high and optimistic on purpose so that the aircraft is quite versatile.

There is a good chance the Apache had better low speed characteristics, the Eagle is also much lighter aircraft with a design empty weight 1900 lb hence most flights cab ne performed well under a PA-23's weight.





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On 6/2/2019 at 5:54 PM, jfsimon1981 said:

Good day,


As far as my understanding is, the PA-23 might have be designed with a certain max normal cruise speed lying in the region of 150 kt.


Given what seems saying the airfoil, past below alpha zero degree, the drag coeficient 'jumps', hence it would be difficult to accelerate beyond this IAS (flight characteristics rapidly decreasing above).


The Eagle aircraft is based on a simple airfoil NACA 2412, I checked its L/D is 9.0 at max cruise, which is relatively high and optimistic on purpose so that the aircraft is quite versatile.

There is a good chance the Apache had better low speed characteristics, the Eagle is also much lighter aircraft with a design empty weight 1900 lb hence most flights cab ne performed well under a PA-23's weight.






Just purchased and flew your little jewel.  Creamy smooth - perhaps too smooth, feels like a jet rather than a recip.  Didn't try too much - power on stall, full flaps, gear up showed about 45 kt and it broke left.  Need to study your airspeed a little more - seems a lot of pitch down to maintain Vmc with full flaps on final approach.  The design has a lot of retro for today's crowd but it's all very well done - love to see more.  

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