Replacement parts available: Aft landing gear fairings

[bradp]

Hi all - 

I have molds for aft gear fairings and I made a set of replacement aft landing gear fairings for @kaufmath.  I also made some brackets for G5 installations for me and for Ron in Sonoma.   I am about to run some gear fairings for another mooneyspacer.  I’m deciding how much carbon fabric and epoxy to purchase for the run.  

The rules for owner produced parts are pretty straightforward.  You can either provide me with the data to make them (i.e. send me your old beat up one, send me the part number, or send me a picture of your beat up one with measurements), or be involved / direct the quality assurance (i.e. tell me how to make the part - for example provide me with the part number and tell me to make them with 5 layers of 2k carbon plain weave with a single layer of 4oz fiberglass to meet or exceed the structural integrity of the previous part).  Tell me how I should test for quality assurance (ie brad please jump up and down on the part ten times, visually inspect for resin voids or bridging).  

If parts from mooney are too expensive or not readily available, that suffices as justification for using the owner produced part route.

I'll provide the part without the holes so you can match them up to your particular plane’s hole pattern, and drill them out.  I can either give you the part plain carbon micro beaded and sanded or primed.  Then you show your part to your A&P to make sure it conforms and he should install it.  He should swing the gear to make sure there is no binding / scuffing of the new part.  I don’t want carbon on bare aluminum- so please makes sure that issues of dissimilar metal / dielectric corrosion are addressed appropriately (EDIT- I should clarify that these have an extra layer of glass to abut the skin to avoid carbon on metal). The need for a gear swing I want to be pretty clear about - I don’t want anyone’s gear binding because of fitment issues.  

I'm not planning to charge anything beyond the direct cost of the materials to make the parts and whatever it costs to ship them to you. In the world of fast cheap and good, these are good and cheap but not fast.  I have a full time 60hr week gig and small kids at home so this parts making happens when I get an hour here and there.  Each set of fairings takes about 15-20 hours of love to produce.  

If anyone wants non-structural composite parts (other fairings or interior parts), just let me know and I should be able to make a mold and run a part.  As of now this is just a hobby but I might make it into a little cottage industry (It will remain under the owner-produced rules for now)... trying to support our fleet.  I’m not interested in producing critical or structural parts as of now (so please ask @Sabremech if you need a beautiful prop spinner or replacement cowl).   

PM me to let me know if you’re interested.  

Brad 

 

[Yetti]

How many knot increase for carbon fiber?  Differential in speed increase if you just used E glass?

[jetdriven]

Just put one layer of 5-8oz fiberglass on the bottom of the flange when molding it. That keeps the carbon off the aluminum skin of the plane.  

[bradp]

I have a layer of 4oz fiber sandwiched between the carbon and the plane along the flange.  That and a layer of primer work to keep the carbon off the skin.  These are stronger and lighter than the original ones that get beat up pretty good along the forward edges.  Jumping up and down on a test piece was fun, couldn’t do that with glass :-)

carbon composite work is fun and versatile  - fixed my daughters bed by making a complex slot locking piece overnight rather than trying to find the unicorn horn on the internet or someone to machine a new part  

 -B

[jetdriven]

The originals look like injection molded urethane. Similar to a modern car bumper cover. 

[larrynimmo]

what do you charge for a set of them for the rear fairing like you show in your pictures...

[bradp]

Ballpark It’s about 3 yards of carbon (runs about $20/yd)  plus consumables like epoxy (expensive), so I’m estimating between $65-85 for a pair plus about $10 for shipping.  The more carbon I order the cheaper it gets... like anything else.  

-B

[N231BN]

That is really cool that you are making those fairings. I wish those efforts could be spent making a lower gear door that eliminates the need for the fairing. One of the old Mooney mod companies had an STC for one but they are now defunct. However, that would require a PMA which any sane person would avoid like the plague.

 

One of the main reasons those fairings get so beat up is when your shock discs become less pliable they don't extend the gear to the same length so the doors don't line up very well. A bad design on Mooney's part which was greatly improved on the 252.

 

I'm in for a pair, thanks.

[jetdriven]

There does exist a mold for an owner-produced version of that Modworks lower gear door. 

[bradp]

@testwest has that mod works part that eliminates the need for the aft gear fairing.  It does require the caliper rotation I believe.  Found a pic of his belly on the inter webs. Notice how they eliminate the aft gear fairing that I have molds for  

I’m learning a bit more about the applicability of these inner gear doors beyond the Modern a Mooney  I’ll post a QA and look to the group to correct as necessary

 

[bradp]

QA: 

1) Are these fairings the same or mirrored?

- they are mirrored so left and right have handed ness and are separate parts   Here’s a picture of one installed...

2) What part is this and what part number does this replace? 

The part number for a J (#30 in the figure below) is 550060-007 LH and 550060-008 RH  

 

The parts catalog I can find online (cat no 205) for CDEF models does not reference inner gear doors or aft fear fairings, however a number of E/F/C with electric gear 40:1 actuators do have inner gear doors and aft gear fairings installed.  The inner gear doors tend to pull the gear down, so from what I’ve read I’d If you have a Johnson bar Mooney you really may not want  the inner gear doors and aft fairings because it makes Johnson bar actuation more difficult unless at very low airspeed.  

3) Should I have these aft fairings on my plane? I think they might be missing. 

- If you have a J model or above then they should have come installed OEM with your plane.  I’m not sure about the modern day / long body Moonies.  Having had mine off for a year they give you about a 3-4 mph drag penalty at cruise if you have inner gear doors on and aft fairings removed.  You should only have aft fairings if you have factor inner gear doors installed  (see below)

4) I don’t have inner gear doors, should I have these aft gear fairings then? 

- No, this is only if inner gear doors are installed.   Otherwise the aft fairings   would create an additional drag penalty.  Factory inner gear doors look like this...

No inner gear doors look like this...

5) Why would I want / need to replace these.  

- I originally repaired mine because the corners had become torn due to rocks / old pucks with the main gear door rigging misaligned.  I made molds thinking they’d be useful to have one day.  I’m also thinking about creating a small area for a diagonally / inward pointed taxi light that could fit in the fairing, but that may be a future project / idea.  They had been repaired a few times in situ and the urethane was cracked pretty significantly, so that was the story.  

6) Can you make a set of inner gear doors?

- I can make a set of inner gear doors if the part number matches that for my plane and I pull molds off my inner gear doors (from a 1977 J).  They are a much more complicated part that would require a complex mold in halves but doable.  I’d have to spend some time on these molds.  Installation would be up to you and your A/P under the owner produce parts rules.  I don’t want to step on any STCd parts by making clones unless it’s to repair / replace / unavailable as would be permitted under owner produced parts rules.  If anyone want to provide me either with the Modworks inner gear door mold or a gear door as a template so I can make a mold, I’d be willing to run that part as replacement under owner produced parts rules.  

[Yetti]

1 hour ago, bradp said:

@testwest has that mod works part that eliminates the need for the aft gear fairing.  It does require the caliper rotation I believe.  Found a pic of his belly on the inter webs. Notice how they eliminate the aft gear fairing that I have molds for  

I’m learning a bit more about the applicability of these inner gear doors beyond the Modern a Mooney  I’ll post a QA and look to the group to correct as necessary

 

This looks the most interesting..  Looks like the STC Database is no working... Finally took 12 days for the government shutdown to impact my life.

[EricJ]

2 hours ago, bradp said:

The parts catalog I can find online (cat no 205) for CDEF models does not reference inner gear doors or aft fear fairings, however a number of E/F/C with electric gear 40:1 actuators do have inner gear doors and aft gear fairings installed.  The inner gear doors tend to pull the gear down, so from what I’ve read I’d If you have a Johnson bar Mooney you really may not want  the inner gear doors and aft fairings because it makes Johnson bar actuation more difficult unless at very low airspeed.  

This came up recently locally.   My hangar neighbor has an M20A and says that an earlier neighbor with an M20A that was an engineer did the analysis on the aero forces from the inner doors and determined that a different-sized spring was needed and had one fabbed.   This allowed addition of the inner doors with a Johnson bar, apparently successfully via 337 with a field approval.

On my J if I wait a little too long or am faster than I think I am on a go-around, pulling the gear up above about 90kts will consistently blow the breaker.  When I was doing my IR training I'd have to pre-brief instructors that on missed approach go-around I have to pitch up quite a bit before I can pull the gear up, so don't be alarmed.   I didn't fully appreciate until recently that this is probably largely a consequence of the aero forces from the inner gear doors.

[jetdriven]

10 hours ago, bradp said:

QA: 

1) Are these fairings the same or mirrored?

- they are mirrored so left and right have handed ness and are separate parts   Here’s a picture of one installed...

2) What part is this and what part number does this replace? 

The part number for a J (#30 in the figure below) is 550060-007 LH and 550060-008 RH  

 

The parts catalog I can find online (cat no 205) for CDEF models does not reference inner gear doors or aft fear fairings, however a number of E/F/C with electric gear 40:1 actuators do have inner gear doors and aft gear fairings installed.  The inner gear doors tend to pull the gear down, so from what I’ve read I’d If you have a Johnson bar Mooney you really may not want  the inner gear doors and aft fairings because it makes Johnson bar actuation more difficult unless at very low airspeed.  

3) Should I have these aft fairings on my plane? I think they might be missing. 

- If you have a J model or above then they should have come installed OEM with your plane.  I’m not sure about the modern day / long body Moonies.  Having had mine off for a year they give you about a 3-4 mph drag penalty at cruise if you have inner gear doors on and aft fairings removed.  You should only have aft fairings if you have factor inner gear doors installed  (see below)

4) I don’t have inner gear doors, should I have these aft gear fairings then? 

- No, this is only if inner gear doors are installed.   Otherwise the aft fairings   would create an additional drag penalty.  Factory inner gear doors look like this...

No inner gear doors look like this...

5) Why would I want / need to replace these.  

- I originally repaired mine because the corners had become torn due to rocks / old pucks with the main gear door rigging misaligned.  I made molds thinking they’d be useful to have one day.  I’m also thinking about creating a small area for a diagonally / inward pointed taxi light that could fit in the fairing, but that may be a future project / idea.  They had been repaired a few times in situ and the urethane was cracked pretty significantly, so that was the story.  

6) Can you make a set of inner gear doors?

- I can make a set of inner gear doors if the part number matches that for my plane and I pull molds off my inner gear doors (from a 1977 J).  They are a much more complicated part that would require a complex mold in halves but doable.  I’d have to spend some time on these molds.  Installation would be up to you and your A/P under the owner produce parts rules.  I don’t want to step on any STCd parts by making clones unless it’s to repair / replace / unavailable as would be permitted under owner produced parts rules.  If anyone want to provide me either with the Modworks inner gear door mold or a gear door as a template so I can make a mold, I’d be willing to run that part as replacement under owner produced parts rules.  

There are some carbon fiber modworks stc molded gear doors out in the wild, on a couple M20J’s. Unlike the modworks doors, you can slice bologna and cheese with these. They’re about twice as stiff, which is good cause the chopped strand mat in the modworks doors peels away from the wing at 200 mph. 

 

 

Edited January 2, 2019 by jetdriven

[DonMuncy]

10 hours ago, bradp said:

 

 

5) Why would I want / need to replace these.  

 

 

My hangar elf built one for each side because both mine were broken from unknown causes, at different times.

[bradp]

11 minutes ago, jetdriven said:

There are some carbon fiber modworks stc molded gear doors out in the wild, on a couple M20J’s. Unlike the modworks doors, you can slice bologna and cheese with these. They’re about twice as stiff, which is good cause the chopped strand mat in the modworks doors peels away from the wing at 200 mph. 

 

 

Byron do those require the forward caliper rotation? 

[bradp]

8 hours ago, EricJ said:

This came up recently locally.   My hangar neighbor has an M20A and says that an earlier neighbor with an M20A that was an engineer did the analysis on the aero forces from the inner doors and determined that a different-sized spring was needed and had one fabbed.   This allowed addition of the inner doors with a Johnson bar, apparently successfully via 337 with a field approval.

On my J if I wait a little too long or am faster than I think I am on a go-around, pulling the gear up above about 90kts will consistently blow the breaker.  When I was doing my IR training I'd have to pre-brief instructors that on missed approach go-around I have to pitch up quite a bit before I can pull the gear up, so don't be alarmed.   I didn't fully appreciate until recently that this is probably largely a consequence of the aero forces from the inner gear doors.

I forgot to pull my gear up the other day on a go around and didn’t realize it until about 120kts.  No issues retracting the gear. Make sure someone checks your down pleloads - popping the breaker at 90 is a pretty good indication of to much force preloads. Your seat pop up a bit when you retract the gear?

[EricJ]

2 hours ago, bradp said:

I forgot to pull my gear up the other day on a go around and didn’t realize it until about 120kts.  No issues retracting the gear. Make sure someone checks your down pleloads - popping the breaker at 90 is a pretty good indication of to much force preloads. Your seat pop up a bit when you retract the gear?

Preloads were checked at annual and by Maxwell's shop during the PPI.  No seat pop.
 

[jetdriven]

9 hours ago, bradp said:

Byron do those require the forward caliper rotation? 

Yes. They are molded from modworks doors. Dimensionally exactly the same.   If you already have the STC installation, it is an owner-produced part. 

Edited January 2, 2019 by jetdriven

[N231BN]

Has anyone tried to get a field approval since the STC is unavailable?

[jetdriven]

The FSDO will tell you the STC is current and valid even though the owner of modworks skipped town with 1M of customer deposits over ten years ago. 

[bradp]

We just need a Mooneyspace STC process. 

A bunch of carbon and fiber ordered will start  parts Monday. 

Brad 

[M20F-1968]

On 1/1/2019 at 11:44 AM, bluehighwayflyer said:

Very, very nice work, Brad. Along these lines, I have a brand new set of aluminum inner gear doors that are still in the box from Mooney if anyone needs a new set. These things take a beating and I bought them for my previous J when I was afraid Mooney was going to go out of business.  The set costs about $1500 from Mooney.  I’ll take 20 percent off of that and pay for the shipping.

Jim

Jim:

PM sent

John Breda

[bradp]

Needed some method for keeping materials straight. My 5 year old daughter made this with me.  She likes drilling and wearing eye protection  ... a lot. 

 

Bob’s fairings are up and curing 

[skykrawler]

The STC number for the lower gear doors is SA4382WP or SA00803AT (later models).

 

From https://www.faa.gov/documentlibrary/media/order/8110.120.pdf:

b.  Abandoned STCs and TCs.  Section 44704(a)(5) allows the Administrator to release data on TCs or STCs that have been inactive for 3 or more years.  The statute requires the agency do a search for such activity.  When no activity is found, the FAA refers to these certificates as abandoned.  This order describes the process for making the determination that an STC or TC has been abandoned, and how and what data the FAA may release to third parties.

If you read through the whole mess it basically says once the STC has been surrendered or abandoned the 'data' may be released for maintaining existing STC'd aircraft.  The data cannot be used to apply for a new STC.  What this means is to keep the STC usable in terms of modifying aircraft it needs to be purchased from the STC owner.  STC owners are required to 'maintain' the engineering data for the STC including any engineering changes required that might  arise from problems.  There is also liability.