600115-005 intake duct

[DCarlton]

1 hour ago, EricJ said:

You can see the air filter here just in front of the #2 cylinder.   The air box can be seen behind it and going down below the starter to where the fuel servo intake is.   I have some foil tape on the the cover from the ram air delete kit where that air used to come in.

That's where my head was going.  I don't have drawings or pics in front of me, just shooting from the hip, but I was wondering if it would be easier to develop an STC to eliminate the accordion boot.  

[Fly Boomer]

40 minutes ago, DCarlton said:

That's where my head was going.  I don't have drawings or pics in front of me, just shooting from the hip, but I was wondering if it would be easier to develop an STC to eliminate the accordion boot.  

The fact that later models were done that way should help grease the wheels.  Nothing is easy with the FAA but, in this case, you would not be fabricating something from whole cloth.

[EricJ]

5 hours ago, DCarlton said:

That's where my head was going.  I don't have drawings or pics in front of me, just shooting from the hip, but I was wondering if it would be easier to develop an STC to eliminate the accordion boot.  

A really cool thing would be to just get a J cowl, air box, and oil cooler setup.   Those cure a lot of ills and just make life much easier.   I always sympathize with people who have to deal with the earlier cowls.   The J cowl is super easy to deal with.

[Ragsf15e]

8 minutes ago, EricJ said:

A really cool thing would be to just get a J cowl, air box, and oil cooler setup.   Those cure a lot of ills and just make life much easier.   I always sympathize with people who have to deal with the earlier cowls.   The J cowl is super easy to deal with.

Yeah that’s where the issue is.  Getting a J cowl and then relocating everything is difficult and expensive. There use to be a few people doing it but I don’t think J cowls are easy to get and they aren’t cheap.  It would be a great mod to have though for several reasons.

[cliffy]

If you an just replace with already approved Mooney parts it even qualifies as a 'Minor Alteration' and only a log book entry is required by any A&P

[Allen_D]

I've made some progress, and the urethane part is slightly stiffer than the original using a shore 90A material. I am considering switching to shore 80A as might be a closer match. Currently I'm using amber urethane to spot air bubbles. Once bubble elimination method is sorted, transitioning to black.

Seeking feedback on this progress.

[Andy95W]

That certainly looks good!

Could you embed a wire in the ribs to prevent collapse, like the original has?  My biggest fear would be inadvertent flight into icing conditions that ices over the air filter- which then collapses the ductwork which kills the engine.

[cliffy]

How will the flanges be stiffened?

The bellows look good but I have the same concern as Andy95W

[Shadrach]

I could be wrong, but I don’t think the mesh in the original part adds any rigidity. As far as I can tell, it’s cotton or a similar material. It certainly adds shear and tensile reinforcement. I think those that are focusing on the mesh as a component of rigidity that prevents collapse have not fully examined a failed boot in a while. They tend to tear from the shear stresses that come with start up and shut down. They tend to fail in same place and the resulting tear tends to look like rubber coated denim that has a hole in it with frayed and soft fabric at the edge of the tear.

[Allen_D]

1 hour ago, Andy95W said:

That certainly looks good!

Could you embed a wire in the ribs to prevent collapse, like the original has?  My biggest fear would be inadvertent flight into icing conditions that ices over the air filter- which then collapses the ductwork which kills the engine.

Thank you for your feedback and concern. It's worth noting that the original design for the E/F models does not incorporate any wire in the ribs.

To address potential concerns about the induction coupler collapsing, I've conducted a Computational Fluid Dynamics (CFD) study and subsequent Finite Element Analysis (FEA) at twice the expected volumetric flow rate. This allowed me to estimate the aerodynamic loads and predict a maximum deflection of approximately 1 mm for the chosen material.

Additionally, in the event of inadvertent flight into icing conditions, the air filter bypass valve is designed to automatically open, preventing engine starvation.

I also plan to monitor the part's deflection during ground operations, particularly during full power run-ups, to ensure structural integrity.

[Allen_D]

1 hour ago, cliffy said:

How will the flanges be stiffened?

The bellows look good but I have the same concern as Andy95W

I believe the stiffness of the flanges is currently sufficient. The lower pressure inside the duct should assist it in sealing. With that said, I do intend to make the flanges thicker on the next iteration. 

EDIT: Also the flanges on the new part are a little too thin because I used a heavy layer of Vaseline as a mold release. 

Edited March 17 by Allen_D

[cliffy]

27 minutes ago, Allen_D said:

I believe the stiffness of the flanges is currently sufficient. The lower pressure inside the duct should assist it in sealing. With that said, I do intend to make the flanges thicker on the next iteration. 

EDIT: Also the flanges on the new part are a little too thin because I used a heavy layer of Vaseline as a mold release. 

Thank you for the explanation   Your investigation analysis seems quite good but I have no idea how to do Fluid Dynamic Analysis   Way beyond my basic mechanics vocational work. Keep going please 

[EricJ]

49 minutes ago, Allen_D said:

Thank you for your feedback and concern. It's worth noting that the original design for the E/F models does not incorporate any wire in the ribs.

To address potential concerns about the induction coupler collapsing, I've conducted a Computational Fluid Dynamics (CFD) study and subsequent Finite Element Analysis (FEA) at twice the expected volumetric flow rate. This allowed me to estimate the aerodynamic loads and predict a maximum deflection of approximately 1 mm for the chosen material.

Additionally, in the event of inadvertent flight into icing conditions, the air filter bypass valve is designed to automatically open, preventing engine starvation.

I also plan to monitor the part's deflection during ground operations, particularly during full power run-ups, to ensure structural integrity.

A good thing to test/simulate/demonstrate is what happens when the material starts to tear or is damaged in various places due either to cycle fatigue or heat or maintenance or interference from other components (potentially improperly installed) inside the cowl.   The behavior of the part while it is failing is often the motivation for adding reinforcing material.

[MikeOH]

@Allen_D

Basic shape looks great!  That took some work to get just to that point!  Nice work

I, too, share some others' concern with the lack of reinforcement be it wire or some type of thread.  Even if it turns out it is not needed for any mechanical reasons, it may prevent 'chunks' of material from being sucked into the engine as deterioration sets in with age.  To phrase the concern in a slightly different way: Until you can answer WHY Mooney designed the part WITH reinforcement, it is tough to argue for leaving it out.

While there is no question CFD is a powerful and useful tool, it is still based on modeling.  Both actual pressure and vacuum testing (ideally cycling under temp extremes) would go a long way to proving the design in conditions more representative of actual application use.

What are your plans for environmental and life testing? E.g. HAST, shock & vibe, temp cycle, etc.  I get it if you are not there yet, but my opinion is that you will need that testing to fully vet the part prior to any approval.

[Shadrach]

4 hours ago, Allen_D said:

I've made some progress, and the urethane part is slightly stiffer than the original using a shore 90A material. I am considering switching to shore 80A as might be a closer match. Currently I'm using amber urethane to spot air bubbles. Once bubble elimination method is sorted, transitioning to black.

Seeking feedback on this progress.

Allen, I am very impressed with the prototype and your development methodology. Thank you for all your hard work. look forward to more updates..

[Andy95W]

4 hours ago, Allen_D said:

Thank you for your feedback and concern. It's worth noting that the original design for the E/F models does not incorporate any wire in the ribs.

I didn’t know that- thanks.  My C’s boot has metal reinforcement, so I assumed the E/F did also.

I think this would certainly qualify for installation under the new MOSAIC rules if the “real” part wasn’t available. I would certainly consider it if I owned an E/F.

When will you begin work for the carbureted B/C/D/G intakes? 

[Allen_D]

1 hour ago, Andy95W said:

I didn’t know that- thanks.  My C’s boot has metal reinforcement, so I assumed the E/F did also.

I think this would certainly qualify for installation under the new MOSAIC rules if the “real” part wasn’t available. I would certainly consider it if I owned an E/F.

When will you begin work for the carbureted B/C/D/G intakes? 

Are you at Willow Run?

[Andy95W]

New Hudson

[N201MKTurbo]

1 hour ago, Andy95W said:

I didn’t know that- thanks.  My C’s boot has metal reinforcement, so I assumed the E/F did also.

I think this would certainly qualify for installation under the new MOSAIC rules if the “real” part wasn’t available. I would certainly consider it if I owned an E/F.

When will you begin work for the carbureted B/C/D/G intakes? 

Someone sent me a worn out duct for a C Mooney. I disassembled it and figured out how it was made.

It is actually made like a scat tube. A wire is spiral wound around a form. Then a single sheet of fabric reinforced uncured rubber is wrapped around the wire with a 30% overlap at the top of the duct. Then  an uncured rubber coated string is wrapped around in between the wire spirals. 
 

It appears the ends were left to extend a few inches and were cut at the corners. The ends were sandwiched between two die cut pieces of reinforced rubber. Additional pieces were added to seal the corner cuts. This whole sandwich appeared to be clamped into a metal press jig of some sort to form the ends. I assume the whole arrangement was put into the curing oven and vulcanized. 
 

After curing, the ends were trimmed, and part numbers were pad printed on the end flange.

[podair]

Hi ! any success in building a replacement part? Any news where I could get one of these? Mine is soon going to fall apart. Thanks!

[Ragsf15e]

10 hours ago, podair said:

Hi ! any success in building a replacement part? Any news where I could get one of these? Mine is soon going to fall apart. Thanks!

We’re all wondering that same thing… where to get them.  I ordered one from lasar ~6 months ago.  Supposedly, when Mooney has enough orders through MSCs, they will order a batch. No luck so far.  I tried several recyclers without luck as well.

[DCarlton]

2 hours ago, Ragsf15e said:

We’re all wondering that same thing… where to get them.  I ordered one from lasar ~6 months ago.  Supposedly, when Mooney has enough orders through MSCs, they will order a batch. No luck so far.  I tried several recyclers without luck as well.

I ordered one too.  Would be good if we could somehow tally the folks on Mooneyspace that needs or wants one.  

[DCarlton]

Heads up all.  I just placed an order with LASAR after being on the wait list for several months.  Heather is taking a 50% deposit via credit card.  Estimated 35 weeks lead time.  If you foresee needing one, recommend calling her now:  

Heather S., Lasar Inc. 

 

541-398-7430- Direct Line

707-263-0412, #2 Parts Dept.

[Derrickearly]

Looks like I need one of these too.  My mechanic's finger can pass right through a hole in the top.

[Ragsf15e]

39 minutes ago, Derrickearly said:

Looks like I need one of these too.  My mechanic's finger can pass right through a hole in the top.

Yep, you need one then.  You’re pulling unfiltered air right into the fuel servo and through into the engine.  There may be some temporary repairs that could work depending on your mechanics comfort level.  The lead time for the new one is at least 35 weeks, so you’ll want to call Lasar asap.