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Overhead vent upgrade project


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So I am currently in a very extensive annual and decided while the plane was down for a while and torn apart I might as well upgrade my Mooney from the broken plastic overhead vents to some modern eyeball vents. First idea was to order some vents from Wisconsin Aviation.  After receiving those I took them in to the AP/IA to see what he thought.  Unfortunately he had two conditions

1. They need to come from a company that made the vents for an airplane.  They fit this description.

2. I couldn't cut the plenum to install whatever I was going to use....the instructions for the Wisconsin Aviation vents clearly stated you had to cut the plenum to install them, so no go!

I had to come up with a plan B.  After much thought and research I came up with the idea of thermoforming some adapter pieces out of ABS plastic to space the new vents away from the plenum.  I also wanted metal eyeball vents so I ordered some from aircraft spruce.  The ones I ended up with are much nicer that the plastic ones from Wisconsin Aviation.  Now the hard work.

First I had to build a vacuum forming table, a heating chamber, and make the appropriate form to make the parts.  I used 1/8" thick ABS which created really strong parts, likely way stronger than they need to be.  It took a couple attempts to get the form right and I ruined a bunch of plastic figuring out the correct amount of heat, but with some trial and error I think I got it figured out.  

I think they turned out well.   Tomorrow I will take them in for the IA to review and if they get his blessing I'll work on getting them installed.  Here are some pics of the project so far. 

IMG_20211227_184517262.thumb.jpg.bc1d14958188270488bce6f8772d12d4.jpgIMG_20211227_184528849.thumb.jpg.686747031b38652d0152811a691f80c6.jpgIMG_20211227_185709765.thumb.jpg.97dfd40f64fa48d320949d1aa65e9344.jpgIMG_20211227_205146875_HDR.thumb.jpg.336d3c49a94a708ae343df9581a955b6.jpgIMG_20211227_205513152_HDR.thumb.jpg.6408bc95b2869f53ab5e67069baf117a.jpgIMG_20211227_205950750.thumb.jpg.6c8d0accd58bc87be640383e7ca5ea85.jpgIMG_20211227_210615296_HDR.thumb.jpg.ee18b0be6723c359a1c38b3a67985c66.jpgIMG_20211227_211217001_HDR.thumb.jpg.d99f6d4c6384b9cff4810daac516fbc9.jpgIMG_20211227_211640844_HDR.thumb.jpg.0170a512c7de33aa1f14713994d871c8.jpg

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Nice work.

You will find that an angle would be better. The vents won’t swivel enough to point the air where you want it. I did the same thing, but put the Wemac’s on a piece of sheet metal with fabric glued to it. They don’t swivel far enough. They need to be angled toward the passenger’s head.

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So I am currently in a very extensive annual and decided while the plane was down for a while and torn apart I might as well upgrade my Mooney from the broken plastic overhead vents to some modern eyeball vents. First idea was to order some vents from Wisconsin Aviation.  After receiving those I took them in to the AP/IA to see what he thought.  Unfortunately he had two conditions
1. They need to come from a company that made the vents for an airplane.  They fit this description.
2. I couldn't cut the plenum to install whatever I was going to use....the instructions for the Wisconsin Aviation vents clearly stated you had to cut the plenum to install them, so no go!
I had to come up with a plan B.  After much thought and research I came up with the idea of thermoforming some adapter pieces out of ABS plastic to space the new vents away from the plenum.  I also wanted metal eyeball vents so I ordered some from aircraft spruce.  The ones I ended up with are much nicer that the plastic ones from Wisconsin Aviation.  Now the hard work.
First I had to build a vacuum forming table, a heating chamber, and make the appropriate form to make the parts.  I used 1/8" thick ABS which created really strong parts, likely way stronger than they need to be.  It took a couple attempts to get the form right and I ruined a bunch of plastic figuring out the correct amount of heat, but with some trial and error I think I got it figured out.  
I think they turned out well.   Tomorrow I will take them in for the IA to review and if they get his blessing I'll work on getting them installed.  Here are some pics of the project so far. 
IMG_20211227_184517262.thumb.jpg.bc1d14958188270488bce6f8772d12d4.jpgIMG_20211227_184528849.thumb.jpg.686747031b38652d0152811a691f80c6.jpgIMG_20211227_185709765.thumb.jpg.97dfd40f64fa48d320949d1aa65e9344.jpgIMG_20211227_205146875_HDR.thumb.jpg.336d3c49a94a708ae343df9581a955b6.jpgIMG_20211227_205513152_HDR.thumb.jpg.6408bc95b2869f53ab5e67069baf117a.jpgIMG_20211227_205950750.thumb.jpg.6c8d0accd58bc87be640383e7ca5ea85.jpgIMG_20211227_210615296_HDR.thumb.jpg.ee18b0be6723c359a1c38b3a67985c66.jpgIMG_20211227_211217001_HDR.thumb.jpg.d99f6d4c6384b9cff4810daac516fbc9.jpgIMG_20211227_211640844_HDR.thumb.jpg.0170a512c7de33aa1f14713994d871c8.jpg

BTW do you have a picture of how they look installed? I really like them


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3 hours ago, N201MKTurbo said:

Nice work.

You will find that an angle would be better. The vents won’t swivel enough to point the air where you want it. I did the same thing, but put the Wemac’s on a piece of sheet metal with fabric glued to it. They don’t swivel far enough. They need to be angled toward the passenger’s head.

Interesting.   You may be right. I'll see how they look installed, if there isn't enough play I'll just have to sand down the top of the form at an angle to get the vent pointed in the right direction.  The current form is the 4th iteration, so why not a 5th the at this point, haha!

I appreciate the feedback!  

 

 

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1 minute ago, Utah20Gflyer said:

Interesting.   You may be right. I'll see how they look installed, if there isn't enough play I'll just have to sand down the top of the form at an angle to get the vent pointed in the right direction.  The current form is the 4th iteration, so why not a 5th the at this point, haha!

I appreciate the feedback!  

 

 

I think I would sand down the bottom of the form. The shape of the top fits the Wemac pretty good.

What would it take to get 4 of them when you get it figured out? Just the formed plastic sheets would be fine, I can do the finish work.

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Here is an update, I wedged the parts in where they would go and evaluated whether the vents had enough articulation to hit me in the face - which is where I prefer the air to go when I'm using overhead vents.  In the front seats it looks like I could get them to hit me in the chin.  The back seats however only the chest.  I'm going to consider how to implement N201MKturbo's suggestion and introduce an angle to the part so they can be aimed more effectively.   Below is a picture of how they look just setting in place with the current part.

Unfortunately I'm just working with the tools a guy in construction would have and not any cnc equipment, so I have to really think through how to make a part that isn't symmetrical.   I'm thinking I may screw the mold to another piece of wood so I can cut the bottom in my miter saw, then add more wood to the cut side and reform again with the grinder/flapdisk.   

 

IMG_20211228_121842955_HDR.thumb.jpg.6b7363ef399443ed4df1979267931a2c.jpg

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7 minutes ago, Utah20Gflyer said:

Here is an update, I wedged the parts in where they would go and evaluated whether the vents had enough articulation to hit me in the face - which is where I prefer the air to go when I'm using overhead vents.  In the front seats it looks like I could get them to hit me in the chin.  The back seats however only the chest.  I'm going to consider how to implement N201MKturbo's suggestion and introduce an angle to the part so they can be aimed more effectively.   Below is a picture of how they look just setting in place with the current part.

Unfortunately I'm just working with the tools a guy in construction would have and not any cnc equipment, so I have to really think through how to make a part that isn't symmetrical.   I'm thinking I may screw the mold to another piece of wood so I can cut the bottom in my miter saw, then add more wood to the cut side and reform again with the grinder/flapdisk.   

 

IMG_20211228_121842955_HDR.thumb.jpg.6b7363ef399443ed4df1979267931a2c.jpg

Don't apologize, so far you are the premier vacu-former on Mooneyspace!

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I have done a lot of thermoforming…

Utah, you are on the right track!

 Nice work.

you might want to get a look at some modern Mooneys to see how their Wemacs are handling the aiming…

They may have the same limitations that you have bumped into…

There are so many good sources for air in the Ovation, that the over head vents aren’t often used in my plane…

Best regards,

-a-

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Nicely done and looking forward to the next version.    I've been on a path to do something similar but was just going to use ABS and a heat gun to form it.   Vacu-form is better, just more work.   I'm lazy.  ;)

You can definitely sell some of these for "other" applications if you're so inclined.   I'd be a customer.

 

 

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You have done good work.  I might adjust the back of your form to make the part angled, and also not hang down so much.  

I made several interior parts when I did my F.  I retrofitted an Ovation interior which is made from fiberglass.  You can easily do hand lay-ups of fiberglass and you will not need to be as fussy with the mold.  Fiberglass can be sanded as needed, re-glassed if required, and worked to the finished size.  You should use a flame retardant resin when you make your final parts.  Sign-off for me was no problem as I had a DER to do those sorts of things.  This should be a minor modification however.

John Breda

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On 12/29/2021 at 2:36 PM, M20F-1968 said:

You have done good work.  I might adjust the back of your form to make the part angled, and also not hang down so much.  

I made several interior parts when I did my F.  I retrofitted an Ovation interior which is made from fiberglass.  You can easily do hand lay-ups of fiberglass and you will not need to be as fussy with the mold.  Fiberglass can be sanded as needed, re-glassed if required, and worked to the finished size.  You should use a flame retardant resin when you make your final parts.  Sign-off for me was no problem as I had a DER to do those sorts of things.  This should be a minor modification however.

John Breda

I considered using fiberglass as I have some experience in that materiel as well but thought getting a good finish would be easier with the abs plastic.  I think a female form so I could do a gel coat would be more difficult than a male form for thermoforming.  Also once you make the heating chamber, vacuum table and form you can make additional units with much less effort than fiberglass I think.  Both are viable and have their pros and cons.  

Thanks for the input! 

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On 12/29/2021 at 10:30 AM, PT20J said:

Very nice. So how much heat and how much vacuum?

Interestingly the amount of heat has been variable. I have had pieces be ready as low as 240 degrees chamber temperature and as high as 300.  Primarily I watch for the material to drop in the holding jig a little more than a inch.   I think the variation in temperature has to do with the rate at which I am heating the chamber.  Currently I use a propane camp stove for heating and I think I am setting it a little differently each time.  The vacuum is being provided by a large shop vac.  Like I said I am just using all the stuff I already have, it would be nice to have more vacuum as I cant seem to pull the plastic into sharp corners.  My first mold actually had a 90 degree shoulder at the bottom of the mold but it wouldn't pull into it so I adapted the mold to get rid of the sharp angles.  

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8 hours ago, Utah20Gflyer said:

Here is version 2.0, I think this one will fit the mission well. You can point it almost straight down or to within maybe 20 degrees of the ceiling.  Also shown left to right is the original vent, Version 1 and then Version 2. 

IMG_20220101_214544213_HDR.jpg

That looks awesome!

Clarence

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22 hours ago, Utah20Gflyer said:

Here is version 2.0, I think this one will fit the mission well. You can point it almost straight down or to within maybe 20 degrees of the ceiling.  Also shown left to right is the original vent, Version 1 and then Version 2. 

IMG_20220101_214544213_HDR.jpg

In all seriousness when can I order 2. 

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