Glass Mountain Optics / FlightSafety Intl.

[OmniAtlas]

Hi Matt,

Any idea where one would be able to purchase fresnel lenses? I would like to experiment with my setup. Limited space so wrap around screen is out of the question, so if I could compensate with depth cues with the front projector/monitor that would be great.

Thanks.

Ben

[xplanematt]

These guys quoted me, a while back, US$200 for a new Fresnel from the AST-300, or US$100 for a used one:

http://customsimulation.com/

Tesla, those seem like pretty slick sims. I'd love to see the interior. Switching them to OLED might be worthwhile. A friend of mine got his hands on a level A Learjet 20-series sim with an early VITAL system (concave mirrors and beamsplitters). Disappointingly, he reported terrible performance when attempting to use this system with LCD monitors. I can't really imagine why. I'd love to try it with flat projection as the image source, myself.

My setup is relatively compact. My projector is above the pilot's head (very close to where the back-projection screen would mount on a modern commercial sim), which is beamed onto a flat screen in front of the pilot. That screen is mounted at about the same angle as a typical aircraft windshield (lots of keystone correction required). Then, my AST-300 Fresnel sits in front of the pilot at almost the same angle (looks like a windshield). The effect is fabulous. My biggest problem is getting this to scale up to more than one channel, and figuring out juxtaposition with the rectangular lens shape (the Glass Mountain unit appears to have a slight trapezoidal shape, making it better suited to juxtaposing with other units).

I had almost settled on doing a large cylindrical screen for my Sabreliner project, until I started flying with the Fresnel. Now I'm on the lookout for more creative, collimated solutions. Gene Buckle has worked out a fabulous collimated system with a spherical mirror (made of Mylar), but it requires a lot of space, as well as extremely precise construction and placement. Ideally, I'll end up with something that is relatively portable.

Matt

[OmniAtlas]

Great, thanks Matt. I will inquire -- any photos on your setup?

The other thing to consider is laser projectors -- the sony pico projector CL1A has ?infinite focus -- the image stays in focus even on a curve screen. Perhaps that could work with a collimated setup. Unfortunately the sony pico projector doesn't meet the lumen or short throw requirements for a home cockpit

[xplanematt]

I'm actually working on the sim a bunch this week, will snap a few pics of the display rig next time I get it fired up.

The laser projectors are interesting, but need to mature before they're really ready for our sims. I am interested in calligraphic displays to augment my current projector setup, but there seems to be no development on that front for consumer/hobby-grade uses (despite the fact that the "big boys" have been using them for years). I'd imagine it's quite difficult and expensive to do.

Matt

[Tesla3D]

https://www.cnet.com/news/led-lcd-vs-oled/
The first substitute of a 19" LED (around $280 about 11 years ago was blurry on movement.
Since then, things have improved every year. One of my 3D systems is 240 HZ so shutter glasses provide 60 hz each L/R for two people viewing different 3D content.
The design of the cockpit shell with a sliding curved door provides both sound and light conditions that add to the experience.

[Tesla3D]

What is better, a 40" Mirror or a 34"x44" Fresnel lens to gather solar energy? As it relates to Simulators:
The Fresnel lens (area=34×44=1496..in 2 $area=34\times 44=\mathrm{1496..}i{n}^2$) might appear to be better than the parabolic mirror (area=π(402 ) 2 =1257..in 2 $area=\pi (\frac{40}{2}{)}^2=\mathrm{1257..}i{n}^2$) because it is concentrating the sunlight from a greater area. But the Fresnel lens has some disadvantages compared to the parabolic mirror that out weigh the small 19% larger area

The Fresnel lens has many concentric rings of glass (or plastic) with their surfaces tilted at slightly different angles to the normal. Perpendicular light from the source is refracted by this glass so the light is redirected toward the focus of the lens.
light is reflected as well as transmitted at each surface according to Snell's Law.
Some sunlight (and visible light in the case of simulators) is absorbed in the glass.

Even for a more expensive "optically perfect" lens, The transition of glass from one ring to the other is not perfectly sharp and area represents waste from an angle of glass that doesn't direct light to the focus.
Fresnel lens using thick glass will be very heavy to mount. Fresnel lens with floppy plastic requires additional mounting to keep it flat or the focus will be degraded. Thinner plastic may even stretch over time.
Assuming the image device is high resolution with a wide color frequency range, glass or plastic will transmit a narrower band of the light frequencies than a silvered metal mirror of the parabola will reflect.

No answer is simple as it often turns out.

My back-of-the-hand suggestion based on my bias (of course):
If low-cost with high quality and least amount of design / construction is the goal -
Look at my simulators. They are proven pre-built beamsplitters and concave mirrors.
Update the 20" monitors with a newer high-resolution tech with high refresh, higher resolution, and brightness - but true color. The cabinet on top can then be shortened (the overall height) by around 20" because that use to be the CRT yoke.
This takes care of the virtual center window - the older Multifunctional displays can be replaced with other instrumentation.
Put the entire set up on wheels. Take it to conventions, shows or other public facing shows.
It would be easy to charge for a 7 minute session and get between $8.00 to $15.00 for a high-resolution experience (that is 6 an hour). A three day event is only around $1,500. This is presently being done with the old, vga direct 7 versions. When my kid was younger and in CAP, I was happy to pay many times more for him to experience flight sims.
I would love to keep two units and work with a team of 5 others with two to develop something together.
But, that is another story.

Article worth watching for 240 Hz refresh rate and motion blur. Also covers Plasma and DLP
https://www.cnet.com/news/what-is-refresh-rate/

[xplanematt]

Here are some shots of my visual system. The construction was done in considerable haste, this is more a proof-of-concept/experiment than a polished sim (this sim is basically a test bed for new ideas).

The black triangular box was adapted from the AST-300, and now houses the projector:


A shot of the Fresnel inside the cockpit...the proximity of the lens as compared to the instrument panel is not ideal from an aesthetics standpoint, but in actual use it's only a minor annoyance:


Looking from the front of the sim, here's the projection screen in front of the pilot:



And finally, a shot of the "hidden room" showing the projector above the cockpit:


The geometry of the system should make it possible to do two of these screens side-by-side for a two-pilot cockpit. Having the two separate (but identical) views would be like some of the older commercial sims. Right now, I just have a 19" monitor mounted on the right side of the cockpit, for instructor use. It mirrors the pilot's view (it's fed directly from the projector's aux output), so it's useful in keeping the instructor abreast of the student's in-flight shenanigans. A less mobile but more versatile option would be to give the instructor a dedicated station outside the cockpit, with the duplicate view, as well as extra screens for maps, failure modes, sim operation, etc. This is the route I'll go with the Sabreliner, most likely.

The immersion factor with this visual system is simply no comparison to the old projector-only setup I had before. I actually WANT to FLY this sim, a lot! I can already tell that getting the outside world completely shut out (by putting on doors, and finishing the instrument panel) will help immersion even more.

The good thing about wanting to fly more than work is that I've had a chance to really put the sim through its paces, and discover/fix various usability and stability issues. The sim has essentially been on a "feature freeze" for several weeks now, and has really matured. Next step is to get my King HSI going (I'm getting a little tired of having to look at WingX Pro on my iPad just to figure out my heading).

Matt

[OmniAtlas]

Hi Matt, this is great!

Thanks for sharing, it is exactly what I've been looking for.

I've been to a few flight simulators (private builders, and commercial -- more for the general public) and have been disappointed with the visuals. Although they have a complete 180 degrees or more wrap around screen, it does not feel immersive.

I am looking to see if using fresnel lenses (as you have done) would be a feasible method and relatively straight forward way to implement a collimated display system.

Could this kind of setup be possible with an A320 visual display setup? It would be difficult to find or source a fresnel lens that large, but perhaps setting up 2 side by side display will still have a good effect?

Cheers,

Ben

[Tesla3D]

Thanks for the post of the C-20 Glass Mountain kit for use with a 20" monitor.
Amazing enough, I was able to contact the individuals at Flight Safety that worked for Glass Mountain who set up the specifications for the Tesla II simulators. Was even able to get a phone call and ask many details about them.
A lot of old rumors dispelled by the pros.
The C-20 is designed for flat screen. The monitors shipped with them were pretty flat for CRT's. But, the mirrors were not set to accommodate the slight curve as some people has misinformed me. That makes them great for the new technology.
Found out a lot more interesting things. Will come back and share that this weekend.

Thanks for the photos up above!

[xplanematt]

Ben,

I know what you mean about underwhelming visuals. They can make or break the whole experience. It's particularly an issue for me, as I'm all about the flying primarily, what happens in the cockpit is not always my focus. I flew an Aeronca Champ today that had airspeed, altimeter, compass, and not much else. Most of my time was spent looking out the generously-sized windows.

A few years back, I did get to check out what could probably be considered the pinnacle of non-collimated wrap-around visuals, at Flight Safety. It was a level 6 FTD for a Eurocopter sim. The system itself was amazing (the actual graphics, not so much...they were using Google Earth...), having such a huge FOV filled by seamless sim graphics really gave a great flying experience, especially since it was a heli. But, I have to say, it did not have the same "wow" factor or level of immersion as a good collimated system. It's hard to explain, there's just something about those systems that just pulls you into the virtual world like nothing else. Not even virtual reality glasses are any match for it.

Anyways, Ben, if you try to use this system on a big cockpit like an Airbus, you're going to run into the same issues the big boys used to have, such as seams between the channels, and getting each channel to look right from both pilot positions. But we do have some display technology now (such as cheap bright DLP projectors) that those old systems did not have. If I were to try this on a bigger cockpit, I'd probably start by doing 3 to 5 flat projection screens, with a projector beaming onto each, and an equal number of big Fresnel lenses in front of them, but with nothing separating these screens/lenses from each other. What I find with my rig is that I can move my head around quite a bit and still get a good image. I also find that the edges of the image get "pulled" a bit, sort of like the fisheye effect you get with a spherical system. This is a GOOD thing, as it gets us away from the unrealistic flat image we typically see in projection systems.

Tesla3D, that's some exciting news about the Flight Safety stuff. Keep us updated, I'm looking forward to hearing about it!

I'm attaching a few shots of that helicopter system in case you guys are curious. Sorry these are of such low quality, the light was very low for the visual system to look right. One thing that struck me about this system was when it crashed/reset (not on my flight, hehehe) all the projectors went red....I noticed a LOT of projectors with a LOT of overlap. That was surprising.

Matt