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Impressions ….. Aerobask ViperJet LXR

Introduction

The ViperJet sounds interesting but, before starting with these impressions of the Aerobask version, I think it’s worth providing some background information.

The Viper Jet is a small homebuilt jet aircraft produced by Viper Aircraft Corporation. It is a conventional, low-wing monoplane with swept wings and tail, and has two seats in tandem under a bubble canopy. The jet intakes are located at the sides of the fuselage and the tricycle undercarriage is retractable. Construction throughout is of composite materials.

Originally conceived to use a piston engine driving a five- or six-blade pusher propeller, brothers Scott and Dan Hanchette commenced work on the prototype, then known as the ViperFan, in February 1996. However, concerns about the difficulty and cost associated with eliminating vibration from the drivetrain led the Hanchettes to choose turbojet propulsion instead, and they installed a Turbomeca Marbore engine instead of the Continental flat-6 they had originally envisaged as a powerplant.

In 2006, the base MKII kit cost US$182,000, but since builders can purchase additional components already pre-made by Viper Aircraft, customers spent an average of US$350,000 on their kits. They would then have to spend approximately another US$300,000 and devote around 3,000 to 3,500 hours to complete the aircraft. The company also offers customers a builder assistance programme to help them assemble the major airframe components and a training programme to aid them learning to fly their ViperJet once it is complete.

What do you get?

What do you get or perhaps it’s better to say … what can you expect? The ViperJet LXR is the latest produced aircraft from Aerobask lead developer Stephane Buon. It isn’t particularly a model I expected from Stephane but, on the other hand, it’s an interesting and challenging model to fly. Of course with the aircraft package you get five liveries and several manuals. Regarding the liveries, you have  the following  offerings:
– N520VF-Orange
– N521VF-Red
– N522VF-Black
– N524VF-Checkerboard
– N525VF-Yellow

As far as I could see and check at the FAA registration database, only the livery with registration N520VF is in fact a ViperJet. Not so very important, but on the other hand, different real ViperJet registrations are available like N899VJ and I could imagine that the N520VF was also included in its original first decor.

In the aircraft document folder you’ll find the following Acrobat manuals:
– Camera preset
– Disclaimer
– Liveries
– Manual v1.0
– Recommended settings
– Sub folder with some real documents

Some of the documents are self-explanatory, but I would like to make some comments on the ‘Recommended settings’ and ‘Manual v1.0’ documents. The ‘Recommended settings’ manual is fine, but it may be a good idea when Aerobask adds some explanation to the red and green squares in this manual since it’s not clear to me what the different colored squares mean. And it would be useful to provide some different options/settings for low, medium and hi performance PCs or Macs too.

Regarding the ‘Manual v1.0’, I would like to make the following observation: it is in total 18 pages, full of the necessary information on how to fly this ViperJet and the manual is divided into three parts. The first one is devoted to the description and operation of the instruments; the second deals with instructions and the last covers the necessary checklists. Although part II explains how to start the engine and how to deal with the pressurization system, a tutorial is not included.

And how to install and where to put it?

That’s entirely up to you. You could view the Aerobask ViperJet LXR as your favourite private fighter, thus in the ‘Fighters’ sub aircraft folder, or you see it as a Speedy Gonzales GA aircraft and that means in the aircraft sub folder ‘General Aviation’.

Quick Ground Check

At first glance you could think ‘that ViperJet has too smooth a skin … no, no, that’s far from realistic’, but when you look at some photos of the real N520VF you’ll see that it does in fact have  a smooth skin. OK, perhaps you might see some weathered spots and a dirty exhaust, but that’s where the comparison ends. It’s a cute aircraft to be honest. One thing is for sure, it’s Speedy Gonzales! That’s for certain. You only need to look at the sleek model to be convinced immediately that this should be, no, must be a fast aircraft.

With the ViperJet parked at the apron, logically without the engine running, it comes up with flags and chocks in place. Using a switch on the left-hand side console you can deactivate or activate the flags and chocks. A little further to the aft of the same console you’ll find the GPU (Ground Power Unit) activation switch. To open the beautifully modelled canopy, you need, on the right- hand side console, to select first the grey knob in a rearwards direction and then move the red CANOPY handle back. This will open the canopy. Closing is in the reverse order.

A quick external look at Aerobask ViperJet demonstrates that the overall 3D model is very well done. However, comparing it with some real N520VF photos, it turns out that not all inspection panels are modelled and/or in the right place. I also have the feeling that the orange livery may not be a replica of the real painting – like the white stripe from the front to the tail, the position of the white/black linework and the aircraft registration figures. Other items that I had hoped would be modelled with more precision are, for example, the MLG (Main Landing Gear) and NLG (Nose Landing Gear) doors outside/inside.

This doesn’t mean the model isn’t a success. No, on the contrary, it’s well made but the small items I highlighted would add that extra touch to the ViperJet and give it a ‘real as it gets’ feeling.  Having informed Stephane Buon about my thoughts and I can confirm that some external modelling will be incorporated and be ready for the next update.

Since it a homemade aircraft kit, the cockpit instruments and seating aren’t fixed items for this aircraft.  They have changed many times during the development and evolvement of the ViperJet. Besides that, it’s a matter of how much money you have and want to spend on buying your favourite DUs (Display Units). The real photos I’ve seen of the N520VF cockpit show only two large DUs on the main instrument panel, but I’ve even seen a ViperJet with three large DUs and a separate GNS 530. To match this the Aerobask ViperJet also has three DUs one of which is the Garmin GNS 530. As expected from Aerobask models, the cockpit is very well modelled, very accurately portraying how panels are made and integrated into each other. The overall cockpit includes realistic modelling of the switches, knobs, circuit breakers, levers, and handles and not forgetting the four standby instruments in the pedestal. Everything is almost perfect including the text or placards on the panels. When you’re not sitting in the front seat, you can still enjoy all the flight experiences on your own instruments in the back although they aren’t the same as in the front. The panels may look very nice, but some weathering or scratches would give it a more realistic look and feel. I miss that a bit, and yes, that’s my personal feeling.

Flight Dynamics or How Does it Fly?

You should not start the ViperJet with engines up and running. No, you must start the aircraft from a cold and dark situation. Connect the GPU, do all your tasks via the checklist and start the engine as described in the manual.

Time to taxi.

Taxiing the ViperJet is easy, and you won’t come across behaviour problems while keeping the Viper on the centerline. It’s an easy aircraft for ground movements and that is good news. Do the last preparations before the takeoff and you’re ready to go. During the takeoff run you’ll notice a strong left drift to the ViperJet so there’s an absolute necessity to steer to the right to keep it on the centerline. At the rotate speed, you can pull the stick and the ViperJet moves gently in the air and, if you want, you can increase the angle of attack more than usual with GA or business aircraft. You’ll be surprised what’s possible, even at low speeds.

Climbing out to 10,000 feet with a vertical speed of between 3000-3500 is no problem for the ViperJet. So, if you want get out of the lower airspace, then this is aircraft for you. I levelled off at 11,000 feet and started carrying out some unusual flight attitudes. Normally with small GA aircraft that would consist of slow speeds, steep turns, stalls etc. With the ViperJet slow speeds are fine and fun, but the enjoyment starts with steep turns, and after that you should try out a steep turn at 90 degrees. OK, you must not forget to add a lot of pitch; otherwise you fall like a rock, but you really feel you are experiencing the real thing and making these kinds of turns is great fun. But there’s even more: loopings, roll the ViperJet around its centerline. Now you are talking! Of course, for these acrobatic flight attitudes you should forget the Autopilot and do it all manually. The ViperJet is, you’ll see and feel yourself, an easy and enjoyable aircraft to fly. How realistic it flies is difficult to say. I don’t own a ViperJet licence and Stephane Buon from Aerobask wasn’t able to find a real ViperJet pilot to help him with testing the flight dynamics of the modelled aircraft. Not surprising as there are only six ViperJets flying around.

Besides the acrobatic flight dynamics, you can also cruise under normal conditions with the AP engaged. The modelled AP is easy to handle, but for those who have some problems understanding all the different modes, just check the user manual that provides detailed information on how to handle the ASP control panel. When you’re familiar with other aircraft from Stephane Buon, you won’t be shocked to see his GDU 370 PFD. According to Stephane The primary flight display (PFD) is based on the Garmin GDU 370. Although Aerobask isn’t striving for a full simulation, our version of the GDU 370 allows for all standard flight operations.

The upper half consists of the speed tape (left, with IAS, GS and TAS), the altitude tape (right, with current altitude, selected altitude, vertical velocity, and barometric pressure), waypoint information (top, with compass) and the attitude indicator (or also known as artificial horizon, center, with indicators for localizer and glideslope).

The lower half shows the horizontal situation indicator (HSI, with indicators for heading and bearings), wind (left of HSI), and trim settings (leftmost and lower right).’

As well as these PDF features, the GDU 370 also offers a setup page. Information can be found on page 12 of the manual. For engine parameters you’ll find the MVP 50T EIS located left of the GDU 370. Oops, what does that mean? This DU offers not only engine parameters, but also fuel information plus other aircraft indicators like voltage, amps, clock etc. Although page 12 offers some setup information for the MVP 50T EIS, I noticed that there’s no section that explains in more detail everything that is available on his DU. Perhaps with the next update this additional information will be included. You won’t find any information about the default Garmin 530 GPS in this Aerobask manual, but for those who want to know more about it, check out this link. It’s a very nice and informative manual that covers the default X-Plane Garmin GNS 530 equipment.

I must not forget to mention what you see when you sit at the second pilot position. The co-pilot’s seat does offer some important instruments and a few are the same as the captain’s seat like the GNS 530, the MVP 50T EIS, but the other flight DUs are of less complexity. What’s then the reason for this seat position? Well, enjoy, relax and have some sightseeing while the captain is doing the hard work.

Up till now, the ViperJet has been a straightforward aircraft to fly, although I can’t confirm how realistic the flight dynamics are. Doing unusual flight attitudes is easy, but there is one flight condition which I really do not know reflects reality and that is the STALL. When you simulate a STALL you get a PRE STALL. The PRE STALL is there to warn you. Fine, but I want to go further than just a PRE STALL, I want to come into a full STALL. I’m not sure if the STALL behaviour of a ViperJet is different from other medium size aircraft, but when it has reached a stall, it doesn’t fall to the right and down. Instead, it looks like it comes into a flat stall; the flat stall results in a vertical speed of only 1000 feet/minute. That’s something quite different from what I expected. Is it real? Sorry, I can’t confirm that.

Descending the ViperJet and preparing for landing is really easy. Of course, you can use all the necessary equipment you have onboard, but visually approaching the runway if very easy and you’ve got a great external view due to the large canopy. Something to complain about …. not at all!

My overall impression is good and it is an easy aircraft to fly. I could have added comments on whether or not the modelled ViperJet reflects reality from a flight dynamics point of view, but as I have said before, finding real ViperJet pilots is very difficult. On the other hand, I would imagine that due to the fact it’s a homebuilt aircraft, it should be able to offer flight dynamics that can be handled by most licensed pilots. If you disagree with this, or have other thoughts, just leave a comment. Every informed comment would be welcome for other readers.

What else?

Let’s first start with the available frame rates. Of course, your actual frame rates depend on so many other things like your monitor size, your CPU, your GPU, your X-Plane rendering settings, which airport you are at, use of SkyMAXX Pro and suchlike.

I can say, yes, my iMac is quite powerful, but it also has its limits. Anyway, with my rendering options set quite high, with SkyMAXX Pro active, I can’t complain at all about this modelled ViperJet and the frame rates. I easily reach 30-40 FPS and perhaps you find that low or medium, but remember to look at rendering settings. When I decide to reduce these settings, the frame rates move up very quickly, but I prefer, as most simmers, to enjoy a ‘as real as it gets’ environment while flying or taxiing around.

The included sound folder of 25MB should tell you that the ViperJet comes with a lot of authentic sounds, but after listening to some of them I wondered if this was the case. That said, I found at YouTube four movies that cover a real ‘Viper Jet Full Flight Roll, Loop, Flyby, Takeoff and Land (no Music)’. The ‘no music’ in the title means what you hear is the real ViperJet sound. For those who are interested, check out these links:
Part 1 Viper Jet Full Flight Roll, Loop, Flyby, Takeoff and Land (no Music)
Part 2 Viper Jet Full Flight Roll, Loop, Flyby, Takeoff and Land (no Music)
Part 3 Viper Jet Full Flight Roll, Loop, Flyby, Takeoff and Land (no Music)
Part 4 Viper Jet Full Flight Roll, Loop, Flyby, Takeoff and Land (no Music)

Summary

Overall a nice homebuilt aircraft brought to you by Aerobask. It’s something different from what we’re used to from Aerobask. The 3D model looks very nice and realistic compared to the real Viper, although I would like to see a little more accuracy, like having the panels modelled too, and a couple of more things on the external skin. The shiny look is realistic so there’s nothing wrong with that and, since the skin is made of composite material, you won’t find many rivets. Actually, hardly any rivets at all! The only items on the external skin you can find are the screws for all the panels.

The cockpit layout is a different story as there’s no golden rule as to what is installed in the instrument panel. Depending on your wallet you can buy fancy and exclusive DUs (Display Units) or you just keep it all within the limits.  For the captain’s position, the modelled ViperJet has a collection of DUs where some are based on previous Aerobask models. I miss an electronic checklist which was, as far as I can recall, included in other models with the GDU 370 installed. The instrumentation of the co-pilot is less complex but, on the other hand, this is a great seat position just to enjoy the external view. The 3D modelling of the cockpit is realistic, although it looks a little too ‘brand new’ so you won’t find any weathering at all. I know that Stephane Buon isn’t keen about adding weathered spots, but perhaps Stephane could consider this for a future update. Although the ViperJets are privately owned aircraft, you never keep it as ‘brand new’ for very long. A little ‘used’ look is in this case even more realistic.

How far the flight dynamics or flight characteristics come close to reality, I’ve got no idea. I don’t have or fly the real ViperJet and Stephane didn’t have the opportunity to have a beta tester in his team who’s a real Viper pilot. On the other hand, it’s a cute small jet that handles great and even on the ground it’s easy to taxi, and straightforward for takeoffs and landings.

Did you have a look at part 4 of the ‘Viper Jet Full Flight Roll, Loop, Flyby, Takeoff and Land’ movie? If not, do so. If you did see the movie, you’ll notice that approaching and landing the Viper wasn’t difficult. I found the Aerobask Viper an easy aircraft for just regular flights as well as aerobatics.

Is it worth checking out the Aerobask ViperJet yourself?

I think so and I encourage you to have a look at the dedicated Aerobask ViperJet LXR web page (http://aerobask.com/viperjet/viperjet-xplane.php). Have fun!

For this review, I used the following payware and freeware add-on products:

Freeware | KFYJ West Point from Marc Leydecker aka Belga12345
Payware | SkyMAXX Pro 3.x

Feel free to contact me if you’ve got additional questions related to this impression. You can reach me via email Angelique.van.Campen@gmail.com.

With Greetings,
Angelique van Campen

 

 

Add-on: Payware Aerobask ViperJet LXR
Publisher | Developer: X-Plane.Org | Aerobask
Description: Realistic rendition of the ViperJet LXR
Software Source / Size: Download / Approximately 451MB (unzipped)
Reviewed by: Angelique van Campen
Published: August 22nd 2015
Hardware specifications: - iMac 27″ 3.5Ghz Late 2013
- Intel i7 3.5Ghz / 3.9Ghz during Boost Mode
- NVIDIA GeForce GTX 780M 4096 MB
- 32 GB 1600 MHz DDR3
- 1 internal 1TB SSD (El Capitan 10.11.4)
- 3 external 1TB SSDs
- Saitek Pro Flight System
Software specifications: - El Capitan (10.11.4) | Yosemite (10.10.5) | Mavericks (10.9.5)
- Windows 10 Professional
- X-Plane 10.45c | X-Plane 10.45m

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