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Avionics Bay and Components v2.0

#11 · January 14, 2023, 11:48 am

Quote from Ron Rollo on January 14, 2023, 11:48 am
Hey guys,

About six weeks ago Shane and I were getting ready to start wiring up our sims and it hit me, we really need wiring diagrams to cover everything outside of the Jet45 Modules to insure we are on the same page with everything.

A lot of the items we planned on building into our sims were fairly easy to figure out, but there are a handful of areas that require some thought and it would be really easy for several guys to arrive at the same outcome while taking different paths. This is a perfect recipe for disaster when it comes to helping one another out with trouble shooting.

To address this issue, I have drawn up 30 wiring diagrams that cover nearly all of the wiring elements that Shane and I have planned outside of the Jet45 AAS and Systems software. This way we are all but guaranteed that our sims will be as close to identical as possible and trouble shooting potential issues will be a breeze.

Look at these wiring diagrams as "par for the course". You don't have to include everything and you can certainly add to them if you like. For me personally, I can't think of anything else I would like to add to them after several years of thinking about what should and needs to be included in order to achieve the level of simulation several of us have in mind.

You can find the latest version of the Jet45AAS System Modules with the wiring diagrams HERE

If you have not done so yet, take a few minutes to look over some of the wiring diagrams. You will find that some of them are fairly easy to follow and only really serve as a "power flow" map to that particular piece of hardware. And other wiring diagrams are a little more complex, like the overhead lights and Pack Air.

In all cases where things can be considered a little more complex, I bench tested the wiring to insure there were no issues. I actually found a couple things that I initially thought should work fine, but only discovered that it needed tweaking during the bench testing.

A good example is the Left overhead light bench test. But before we can cover this in detail, you first have to be aware of how the overhead lights work in the real Lear45 and the easiest way to do that is to refer to real world manuals. If you are not aware, the OVHD lights are a little more complex than what you might think. The other thing that you have to be aware of is I have simplified the way our sims will receive power compared to the real Lear45, so if you are following along in the manuals, you might see discrepancies, but for simulation purposes, these wiring diagrams will work fine.

LEFT OVERHEAD LIGHT OPERATION:

The Left and Right cockpit overhead lights receive power from the R HOT BUS. They are also considered the emergency lighting in the cockpit and have to be manually selected by the pilots. In the real Lear45, the overhead lights will remain illuminated as long as the main batteries have power. In our sims, they will remain illuminated as long as the R Power supply is working. (This is an example of a discrepancy)

The Right overhead light can only be controlled from the R OVHD LTS switch on the FO Crew panel, therefor, it is not necessary to talk about it's function in detail. However, the Left Overhead light can be controlled via a switch at the cabin door, the cabin door "closed" pin switch and the L OVHD LTS switch on the Left Crew panel.

This photo shows the Left overhead light in a cold and dark state, no power in the plane with the exception of the HOT BUSES and the cockpit light switch at the cabin door is off as well as the pot switch in the cockpit.

Here the cabin door is open (meaning the cabin door pin switch is closed) and the cockpit light switch at the cabin door is turned ON. The switch at the cabin door is so that the crew can flip a switch at the door and immediately light up the cockpit to keep from bumping into things while trying to get into the cockpit. We can simulate this by adding a switch just outside of the cockpit on the rear wall if you don't have a cabin section.

Here we have to imagine sitting in the cockpit with the switch at the cabin door ON but now the cabin door is closed. This is important because the whole reason behind this hardware logic is to keep someone from flipping the cabin switch ON in flight and blinding the pilots!

With a quick turn of the L OVHD LTS switch, you are no longer sitting in the dark. In other words, only the pilots have control of what lights are turned on in the cockpit with the cabin door closed. You can't see it in this photo, but the pot has been turned up to light up the WEMAC again.

This wiring logic is designed for two main purposes, to provide light in the cockpit from the cabin door when first entering the aircraft and to keep folks in the cabin from blinding the pilots while in flight by selecting that switch at the cabin door. What this wiring logic does not do is protect itself from accidentally leaving the switches in the cockpit turned on. If those light switches are left on, eventually the batteries will drain because remember, the cockpit overhead lighting is on the R HOT BUS.

However, if the light switches in the cockpit are off and the cabin door switch is on, once the cabin door is closed (cabin door pin is open), the cockpit overhead lights will turn off. If you now or ever plan to build a short cabin section for your sim, this is something that you will want to include in your sim.

One other thing that you will want to do is upgrade you bulbs. If you have acquired real WEMAC lights, most likely they came with 28v bulbs which you have to change out to 12v bulbs. While you are at it, go ahead and switch to an LED version. Depending on which WEMAC lights you have, you need to be aware of how tall your replacement LED bulbs are. Also make sure you look for warm white. The light in the photos above are with the new LED bulb you see here.

And that's it on how to turn a overhead light bulb on!

I don't plan on giving a play by play on all the wiring diagrams but this one was interesting to me and it also helps illustrate the power of a wiring diagram.

In other Avionics Bay related news, I have designed and built up a couple service modules. They will be mounted on the Avionics bay bulkhead. The first one is for the Display Unit cooling fans and Avionics Bay lights.

Each Display Unit gets it's own fan where before, we only had a left fan and a right fan. Two fans worked fine but four fans will work great! It's not a matter of trying to keep something cool, although the fans and placement of them helps to keep the air moving. What it is really about is the sound of the fans.

Maciej gets credit for this idea and that is if we add variable pots to each DU fan, we can fine tune the fans to achieve perfect "avionics noise". Once they are set, you never touch them again. This replaces the idea of buying two or more different types of fans.

The second half of this first Service module is for the Avionics Bay lights. I will have what I call bay lights that will be cool white to help work on things and Flood lights that will be red that I can leave on while in simulation. The pots of course allow you to adjust how bright you want or need the lights. This service module will be one of the first things I add in the Avionics Bay so that I can see what I am doing!

The Environmental Cooling Service Module serves more of a wiring hub for the L&R blowers, relays and variable pots. Not at all needed, but I also added L&R Blower Master switches. These switches and the Pack Air and Hi Flow pots will all be left ON, set and left alone.

Why do we need pots for the blowers you might ask? The Pack Air pot will be set at 6v and the HI FLOW pot will be set at 9v. This will help simulate the sound of the HI FLOW switch being selected and also provide additional airflow from the left and right blowers. For more details on how to wire up the Environmental Cooling system, see the wiring diagrams.

More updates on the Avionics Bay and the wiring soon!

Hey guys,

About six weeks ago Shane and I were getting ready to start wiring up our sims and it hit me, we really need wiring diagrams to cover everything outside of the Jet45 Modules to insure we are on the same page with everything.

A lot of the items we planned on building into our sims were fairly easy to figure out, but there are a handful of areas that require some thought and it would be really easy for several guys to arrive at the same outcome while taking different paths. This is a perfect recipe for disaster when it comes to helping one another out with trouble shooting.

To address this issue, I have drawn up 30 wiring diagrams that cover nearly all of the wiring elements that Shane and I have planned outside of the Jet45 AAS and Systems software. This way we are all but guaranteed that our sims will be as close to identical as possible and trouble shooting potential issues will be a breeze.

Look at these wiring diagrams as "par for the course". You don't have to include everything and you can certainly add to them if you like. For me personally, I can't think of anything else I would like to add to them after several years of thinking about what should and needs to be included in order to achieve the level of simulation several of us have in mind.

You can find the latest version of the Jet45AAS System Modules with the wiring diagrams HERE

If you have not done so yet, take a few minutes to look over some of the wiring diagrams. You will find that some of them are fairly easy to follow and only really serve as a "power flow" map to that particular piece of hardware. And other wiring diagrams are a little more complex, like the overhead lights and Pack Air.

In all cases where things can be considered a little more complex, I bench tested the wiring to insure there were no issues. I actually found a couple things that I initially thought should work fine, but only discovered that it needed tweaking during the bench testing.

A good example is the Left overhead light bench test. But before we can cover this in detail, you first have to be aware of how the overhead lights work in the real Lear45 and the easiest way to do that is to refer to real world manuals. If you are not aware, the OVHD lights are a little more complex than what you might think. The other thing that you have to be aware of is I have simplified the way our sims will receive power compared to the real Lear45, so if you are following along in the manuals, you might see discrepancies, but for simulation purposes, these wiring diagrams will work fine.

LEFT OVERHEAD LIGHT OPERATION:

The Left and Right cockpit overhead lights receive power from the R HOT BUS. They are also considered the emergency lighting in the cockpit and have to be manually selected by the pilots. In the real Lear45, the overhead lights will remain illuminated as long as the main batteries have power. In our sims, they will remain illuminated as long as the R Power supply is working. (This is an example of a discrepancy)

The Right overhead light can only be controlled from the R OVHD LTS switch on the FO Crew panel, therefor, it is not necessary to talk about it's function in detail. However, the Left Overhead light can be controlled via a switch at the cabin door, the cabin door "closed" pin switch and the L OVHD LTS switch on the Left Crew panel.

This photo shows the Left overhead light in a cold and dark state, no power in the plane with the exception of the HOT BUSES and the cockpit light switch at the cabin door is off as well as the pot switch in the cockpit.

Here the cabin door is open (meaning the cabin door pin switch is closed) and the cockpit light switch at the cabin door is turned ON. The switch at the cabin door is so that the crew can flip a switch at the door and immediately light up the cockpit to keep from bumping into things while trying to get into the cockpit. We can simulate this by adding a switch just outside of the cockpit on the rear wall if you don't have a cabin section.

Here we have to imagine sitting in the cockpit with the switch at the cabin door ON but now the cabin door is closed. This is important because the whole reason behind this hardware logic is to keep someone from flipping the cabin switch ON in flight and blinding the pilots!

With a quick turn of the L OVHD LTS switch, you are no longer sitting in the dark. In other words, only the pilots have control of what lights are turned on in the cockpit with the cabin door closed. You can't see it in this photo, but the pot has been turned up to light up the WEMAC again.

This wiring logic is designed for two main purposes, to provide light in the cockpit from the cabin door when first entering the aircraft and to keep folks in the cabin from blinding the pilots while in flight by selecting that switch at the cabin door. What this wiring logic does not do is protect itself from accidentally leaving the switches in the cockpit turned on. If those light switches are left on, eventually the batteries will drain because remember, the cockpit overhead lighting is on the R HOT BUS.

However, if the light switches in the cockpit are off and the cabin door switch is on, once the cabin door is closed (cabin door pin is open), the cockpit overhead lights will turn off. If you now or ever plan to build a short cabin section for your sim, this is something that you will want to include in your sim.

One other thing that you will want to do is upgrade you bulbs. If you have acquired real WEMAC lights, most likely they came with 28v bulbs which you have to change out to 12v bulbs. While you are at it, go ahead and switch to an LED version. Depending on which WEMAC lights you have, you need to be aware of how tall your replacement LED bulbs are. Also make sure you look for warm white. The light in the photos above are with the new LED bulb you see here.

And that's it on how to turn a overhead light bulb on!

I don't plan on giving a play by play on all the wiring diagrams but this one was interesting to me and it also helps illustrate the power of a wiring diagram.

In other Avionics Bay related news, I have designed and built up a couple service modules. They will be mounted on the Avionics bay bulkhead. The first one is for the Display Unit cooling fans and Avionics Bay lights.

Each Display Unit gets it's own fan where before, we only had a left fan and a right fan. Two fans worked fine but four fans will work great! It's not a matter of trying to keep something cool, although the fans and placement of them helps to keep the air moving. What it is really about is the sound of the fans.

Maciej gets credit for this idea and that is if we add variable pots to each DU fan, we can fine tune the fans to achieve perfect "avionics noise". Once they are set, you never touch them again. This replaces the idea of buying two or more different types of fans.

The second half of this first Service module is for the Avionics Bay lights. I will have what I call bay lights that will be cool white to help work on things and Flood lights that will be red that I can leave on while in simulation. The pots of course allow you to adjust how bright you want or need the lights. This service module will be one of the first things I add in the Avionics Bay so that I can see what I am doing!

The Environmental Cooling Service Module serves more of a wiring hub for the L&R blowers, relays and variable pots. Not at all needed, but I also added L&R Blower Master switches. These switches and the Pack Air and Hi Flow pots will all be left ON, set and left alone.

Why do we need pots for the blowers you might ask? The Pack Air pot will be set at 6v and the HI FLOW pot will be set at 9v. This will help simulate the sound of the HI FLOW switch being selected and also provide additional airflow from the left and right blowers. For more details on how to wire up the Environmental Cooling system, see the wiring diagrams.

More updates on the Avionics Bay and the wiring soon!

#12 · May 6, 2023, 2:35 pm

Quote from Ron Rollo on May 6, 2023, 2:35 pm
Hey guys,

We have been busy working on several aspects of the sim, most importantly an all new CDU/FMS UNS1. But in between waiting on development aspects and parts to arrive, progress is being made within the Avionics Bay.

When we first started the overhaul of the Avionics Bay, the ideas we had planned for v2 were not as plentiful as we have today. Even since the last post made in January, a few more good ideas have made their way into the sim!

The main idea is to make all the "dirty" modifications now prior to all the wiring. This way we won't have to pull anything out to make these future changes. Here are a couple more updates that have been completed recently.

First, the addition of two stand alone hot buses. Each side of the aircraft's power supply has a dedicated hot bus. The question is where to mount them? Turns out we have plenty of space on the back side of the lower power panels. However, the bus terminals I chose needed a little modification.

The positive and negative terminal post were gigantic, 1/4" bolts and way too long. I opted to drop them down to size 10 bolts and much shorter.

This way there will be plenty of clearance on the back side of the power panels when latched to the bulkhead.

The other thing we added to the rear side of the power panels were the 12v to 5v DC converters. We need five in total. L LCU, R LCU, PED LCU, L CB Panel LCU and the R CB Panel LCU. To even things out, I added one more that will be a Spare/Test 5v DC converter.

Here is an overview of the new Hot Buses and DC converters mounted and in place.

All that needs to be done now is reinstall the panels and start wiring!

The next thing that was recently added was a sub floor in the base frame under the Avionics Bay floor. Shane and I thought this would be a necessary modification in preparation for the future v2 Dual Pedal System we have designed. The way the new pedal system is designed has the cross connection rod, bell cranks and rudder dampeners mounted under the sub floor. This sub floor hatch will provide easier access to these future components!

After getting it drawn out and proven it was possible to add the hatch, it was time to make it happen. The hatch dimension are 12" x 24". The easiest way to go about cutting the opening in the sub floor was to create a jig. Here it is sitting in the pocket between the shell base frames.

And here is the hatch sitting in the jig pocket. It's just a rectangle but it can be tricky cutting a perfectly square rectangle slightly under sized to fit into the pocket!

In these photos, I already have the latch pockets cut into the hatch. I was able to make these latch pockets with the CNC. Here is the hatch sitting on top of the jig.

After the hole is cut in the sub floor, aluminum trim pieces will be added on all four side to create edges for the hatch to sit on. The easiest way to insure the holes are even and straight is to include them on the jig. Here I have the aluminum strips lined up on the jig transferring the holes.

A fresh coat of paint and installation of the latches completes the hatch.

Here is a close up of one of the latches. I have them counter sunk into the face of the hatch. Again, easy to make happen if you have access to a CNC.

Now the fun part, cutting the hatch hole in the sub floor. First, I used the jig to mark guide lines to jigsaw out the majority of the hole.

The really fun part was routing the hole out upside down which I don't recommend. The safer and easier way would be to unbolt the shell frame from the sub floor and move the shell frame out of the way. In this case, the guide jig would be under the sub floor. But because I did it upside down, the guide jig was on top of the sub floor.

What you are left with is a nice clean hatch hole! You can see how easy it will be to gain access to the future sub floor pedal assembly.

More fun! Here I have the jig mounted to the under side of the newly cut hatch hole. Now I can drill the holes for the aluminum strips using the guide holes in the jig.

I must say this is not a view we have ever seen before! I will have some follow up photos of the Sub Floor Hatch in place when it is fully complete. I need to do some edge and trim painting first.

Last but not least, Shane had a good idea of working out the final details with the blower and ventilation system, also known as the Pack Air system. A good idea to figure out now if there are any additional "dirty" modification needed to the Avionics Bay bulkhead.

As it turns out, not much to modify to the bulkhead itself, but it did get me to spending a little time on the ventilation and Pack Air system. To recap, what we are planning on modeling is a simplified version of the Pack Air System. When the Pack Air Switch is selected, air will blow through the six vents in the cockpit, three vents on each side via two blower motors, one on each side.

If the Pack Air switch is selected, the HI-FLOW switch will also be available. If the HI FLOW switch is selected, the blower motors will step up a notch simulating the HI-FLOW switch being selected. If the Pack Air switch is not selected, the HI-FLOW switch will be Inop.

Besides simulating a simplified version of the Pack Air system, the goal is to pipe in fresh air from two outside intakes mounted at the front lower end of the shell while the four Avionics fans are pulling stale air out of the cockpit. Additionally, we can add a stand alone space heater that can be controlled by the Manual Temp switch for you guys in colder environments. (More on that later)

The first part of the problem to overcome was what tubing to use. The bigger the better when it comes to air volume. But we wanted something that fits through the holes in the shell frames and fits on the smallest scoop inlets also known as plenums. The hose also needs to be flexible and smooth on the inside walls to keep the air moving forward as easy as possible.

What I found that checks most if not all of the boxes was 3/4" I.D. Fountain Tubing!

At $20 for 20 feet, two bundles is plenty to reach all six vents from the blowers. And the 3/4" I.D. is perfect for the air inlets of a couple plenums I have. Keep in mind that the inlets on the Lear45 air vents vary depending which ones you are talking about. In all cases, the real air vents in the Lear45 are bigger than the one I have pictured here.

The problem that we all face is finding authentic aviation air vents, let alone ones that came out of or for a Lera45. If you can find the real things, you will end up paying a very high price for them unless your seller has not a clue what they have. At this point, I have six aviation air vents that will work but none are from a Lear45. However, they will work!

The next problem was finding adapter fittings that mount to the 3" and 4" blower outlets and then to the three 3/4" tubes. Two issues we face, splitting the blower outlet three ways and reducing the outlets from 3" or 4" diameter to 3/4" I.D. After a few hours of search the world wide web, turns out, there is no such thing.

The solution to the problem is to just make the fittings from scratch!

If you are wondering why there are two different sizes, I have two 3" blowers and Shane has two 4" blowers. They are both 12 volts and rated to push about the same amount of air. The question is will they both be as efficient or will one be better than the other? We will see.

I used PVC reducer fittings to plug the air hoses into the adapter. But they needed to be honed out slightly. Additionally, the hoses need to be split (cut) to slide into the pvc fittings.

Here I have the new adapter plates assembled and ready to be installed on the 3" blowers.

And here I have my 3" blowers built up and ready to install under the Avionics Bay floor on the lower bulkhead. I have included a mounting plate with rubber shims to dampen any noise or vibrations that might transfer through the shell frame. One thing about blowers like these is they can be on the loud side, but we believe it's manageable with a couple tricks like this. More on ways to control excessive blower noise later.

A close up of the rubber shock shims. These four mounting points attach directly to the Avionics Bay floor supports.

Last but not least, a close up shot of the custom made adapter for the 3" blowers. If this works as good as it looks, we will be good! I am excited to get them mounted up.

Initial testing proves it blows air through the tubes but not as strong as you might expect. I found that the longer the tubing, the less airflow volume at the airvent outlets. After all, this is a simplified simulated system that adds some functionality but is not perfect. Later down the road this may be an area that we revisit, but for now, I am happy with it. If anyone has ideas or suggestions, please share!

My findings were that the ankle outlets will have less than 2 feet of tubing and have satisfactory air flow. The elbow outlets will be less than four feet long and I found the airflow to be okay. The problem is the overhead vents. If we run the tubing down the side walls of the airframe up the back and then across the top, we are near 12 feet of tubing and the airflow is present but less than desirable.

But there is a short cut route! I found it is possible to route the overhead tubing up the center windscreen post cutting over four feet of length out. This will certainly increase the airflow to the overhead outlets. And as Shane pointed out to me, those vents are right there at your head and you can definitely feel them blowing your hair around. Well that's a problem for me, you have to have hair to blow hair! LOL

We have many other aspects of the Avionics Bay updates in the works and hopefully we will have them all complete in the next month or two.

More updates to come!

Hey guys,

We have been busy working on several aspects of the sim, most importantly an all new CDU/FMS UNS1. But in between waiting on development aspects and parts to arrive, progress is being made within the Avionics Bay.

When we first started the overhaul of the Avionics Bay, the ideas we had planned for v2 were not as plentiful as we have today. Even since the last post made in January, a few more good ideas have made their way into the sim!

The main idea is to make all the "dirty" modifications now prior to all the wiring. This way we won't have to pull anything out to make these future changes. Here are a couple more updates that have been completed recently.

First, the addition of two stand alone hot buses. Each side of the aircraft's power supply has a dedicated hot bus. The question is where to mount them? Turns out we have plenty of space on the back side of the lower power panels. However, the bus terminals I chose needed a little modification.

The positive and negative terminal post were gigantic, 1/4" bolts and way too long. I opted to drop them down to size 10 bolts and much shorter.

This way there will be plenty of clearance on the back side of the power panels when latched to the bulkhead.

The other thing we added to the rear side of the power panels were the 12v to 5v DC converters. We need five in total. L LCU, R LCU, PED LCU, L CB Panel LCU and the R CB Panel LCU. To even things out, I added one more that will be a Spare/Test 5v DC converter.

Here is an overview of the new Hot Buses and DC converters mounted and in place.

All that needs to be done now is reinstall the panels and start wiring!

The next thing that was recently added was a sub floor in the base frame under the Avionics Bay floor. Shane and I thought this would be a necessary modification in preparation for the future v2 Dual Pedal System we have designed. The way the new pedal system is designed has the cross connection rod, bell cranks and rudder dampeners mounted under the sub floor. This sub floor hatch will provide easier access to these future components!

After getting it drawn out and proven it was possible to add the hatch, it was time to make it happen. The hatch dimension are 12" x 24". The easiest way to go about cutting the opening in the sub floor was to create a jig. Here it is sitting in the pocket between the shell base frames.

And here is the hatch sitting in the jig pocket. It's just a rectangle but it can be tricky cutting a perfectly square rectangle slightly under sized to fit into the pocket!

In these photos, I already have the latch pockets cut into the hatch. I was able to make these latch pockets with the CNC. Here is the hatch sitting on top of the jig.

After the hole is cut in the sub floor, aluminum trim pieces will be added on all four side to create edges for the hatch to sit on. The easiest way to insure the holes are even and straight is to include them on the jig. Here I have the aluminum strips lined up on the jig transferring the holes.

A fresh coat of paint and installation of the latches completes the hatch.

Here is a close up of one of the latches. I have them counter sunk into the face of the hatch. Again, easy to make happen if you have access to a CNC.

Now the fun part, cutting the hatch hole in the sub floor. First, I used the jig to mark guide lines to jigsaw out the majority of the hole.

The really fun part was routing the hole out upside down which I don't recommend. The safer and easier way would be to unbolt the shell frame from the sub floor and move the shell frame out of the way. In this case, the guide jig would be under the sub floor. But because I did it upside down, the guide jig was on top of the sub floor.

What you are left with is a nice clean hatch hole! You can see how easy it will be to gain access to the future sub floor pedal assembly.

More fun! Here I have the jig mounted to the under side of the newly cut hatch hole. Now I can drill the holes for the aluminum strips using the guide holes in the jig.

I must say this is not a view we have ever seen before! I will have some follow up photos of the Sub Floor Hatch in place when it is fully complete. I need to do some edge and trim painting first.

Last but not least, Shane had a good idea of working out the final details with the blower and ventilation system, also known as the Pack Air system. A good idea to figure out now if there are any additional "dirty" modification needed to the Avionics Bay bulkhead.

As it turns out, not much to modify to the bulkhead itself, but it did get me to spending a little time on the ventilation and Pack Air system. To recap, what we are planning on modeling is a simplified version of the Pack Air System. When the Pack Air Switch is selected, air will blow through the six vents in the cockpit, three vents on each side via two blower motors, one on each side.

If the Pack Air switch is selected, the HI-FLOW switch will also be available. If the HI FLOW switch is selected, the blower motors will step up a notch simulating the HI-FLOW switch being selected. If the Pack Air switch is not selected, the HI-FLOW switch will be Inop.

Besides simulating a simplified version of the Pack Air system, the goal is to pipe in fresh air from two outside intakes mounted at the front lower end of the shell while the four Avionics fans are pulling stale air out of the cockpit. Additionally, we can add a stand alone space heater that can be controlled by the Manual Temp switch for you guys in colder environments. (More on that later)

The first part of the problem to overcome was what tubing to use. The bigger the better when it comes to air volume. But we wanted something that fits through the holes in the shell frames and fits on the smallest scoop inlets also known as plenums. The hose also needs to be flexible and smooth on the inside walls to keep the air moving forward as easy as possible.

What I found that checks most if not all of the boxes was 3/4" I.D. Fountain Tubing!

At $20 for 20 feet, two bundles is plenty to reach all six vents from the blowers. And the 3/4" I.D. is perfect for the air inlets of a couple plenums I have. Keep in mind that the inlets on the Lear45 air vents vary depending which ones you are talking about. In all cases, the real air vents in the Lear45 are bigger than the one I have pictured here.

The problem that we all face is finding authentic aviation air vents, let alone ones that came out of or for a Lera45. If you can find the real things, you will end up paying a very high price for them unless your seller has not a clue what they have. At this point, I have six aviation air vents that will work but none are from a Lear45. However, they will work!

The next problem was finding adapter fittings that mount to the 3" and 4" blower outlets and then to the three 3/4" tubes. Two issues we face, splitting the blower outlet three ways and reducing the outlets from 3" or 4" diameter to 3/4" I.D. After a few hours of search the world wide web, turns out, there is no such thing.

The solution to the problem is to just make the fittings from scratch!

If you are wondering why there are two different sizes, I have two 3" blowers and Shane has two 4" blowers. They are both 12 volts and rated to push about the same amount of air. The question is will they both be as efficient or will one be better than the other? We will see.

I used PVC reducer fittings to plug the air hoses into the adapter. But they needed to be honed out slightly. Additionally, the hoses need to be split (cut) to slide into the pvc fittings.

Here I have the new adapter plates assembled and ready to be installed on the 3" blowers.

And here I have my 3" blowers built up and ready to install under the Avionics Bay floor on the lower bulkhead. I have included a mounting plate with rubber shims to dampen any noise or vibrations that might transfer through the shell frame. One thing about blowers like these is they can be on the loud side, but we believe it's manageable with a couple tricks like this. More on ways to control excessive blower noise later.

A close up of the rubber shock shims. These four mounting points attach directly to the Avionics Bay floor supports.

Last but not least, a close up shot of the custom made adapter for the 3" blowers. If this works as good as it looks, we will be good! I am excited to get them mounted up.

Initial testing proves it blows air through the tubes but not as strong as you might expect. I found that the longer the tubing, the less airflow volume at the airvent outlets. After all, this is a simplified simulated system that adds some functionality but is not perfect. Later down the road this may be an area that we revisit, but for now, I am happy with it. If anyone has ideas or suggestions, please share!

My findings were that the ankle outlets will have less than 2 feet of tubing and have satisfactory air flow. The elbow outlets will be less than four feet long and I found the airflow to be okay. The problem is the overhead vents. If we run the tubing down the side walls of the airframe up the back and then across the top, we are near 12 feet of tubing and the airflow is present but less than desirable.

But there is a short cut route! I found it is possible to route the overhead tubing up the center windscreen post cutting over four feet of length out. This will certainly increase the airflow to the overhead outlets. And as Shane pointed out to me, those vents are right there at your head and you can definitely feel them blowing your hair around. Well that's a problem for me, you have to have hair to blow hair! LOL

We have many other aspects of the Avionics Bay updates in the works and hopefully we will have them all complete in the next month or two.

More updates to come!

#13 · May 7, 2023, 1:28 am

Hi Ron,

Nice work on the air distribution chamber.

Did you look at food-grade hoses? They have smoother inside walls that dont trap food (or air). Less turbulence, more airflow?

I use them on my machinery as the mill and lathe make hard spiral swarf. This swarf constantly gets stuck creating blockages in conventional vacuum spiral tube but slips through food-grade tube. It is available in many sizes.

Not as cheap as what you have, but worth considering.

#14 · May 7, 2023, 12:13 pm

Thanks for the suggestion Will. I never thought of food tubes. I spent a ton of time on the net with no solid results and then went to a couple hardware stores. One of the associates at a Lowes suggested fountain tubing. This is a good example of finding exactly what we need in a place you would not expect to find it.

As it is, the inside of the fountain tubing is smooth. I tried to take a photo but it was hard to see, so I split it open so that we can see what it looks like.

It's not 100% smooth but pretty darn close. You can see that most of the spiral is on the outside of the tubing. If you look at the cut near the top of the photo, you can see how much of the spiral is on the outside compared to the inside.

The limiting factor to this hose is the inside diameter. Other than that, it is perfect at only one dollar per foot. Very flexible by the way.

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