J-Model Shoulder Harnesses in an F?

[canamex]

After flying across deserts, glaciers, barren Sonoran wasteland, and up the fjords of British Columbia for almost 300 hours with just lap belts I'm realizing it's time to put in shoulder harnesses. I've read through the exhaustive thread on fixed vs. inertial reel belts and I'd like to go for fixed. Alpha's offering is clear and I might go that route however...

I've found some used J-model belts for sale on ebay for about a third of the price of new ones from Alpha. Does anyone know if the J-belts will fit into my F-model?

Edited January 4, 2022 by canamex
drama

[Marauder]

After flying across deserts, glaciers, barren Sonoran wasteland, and up the fjords of British Columbia for almost 300 hours with just lap belts I'm realizing it's time to put in shoulder harnesses. I've read through the exhaustive thread on fixed vs. inertial reel belts and I'd like to go for fixed. Alpha's offering is clear and I might go that route however...
I've found some used J-model belts for sale on ebay for about a third of the price of new ones from Alpha. Does anyone know if the J-belts will fit into my F-model?

My 75F didn’t come with shoulder harness either. I never looked to see if Mooney made an attachment point on the roll cage for the shoulder harness. If they did, then a J belt probably won’t work. In my case, the harness came with attachment hardware.

I’d be careful with used belts. You never really know their history and true condition.


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[Ron McBride]

When I installed Alpha belts in my 69F, with the kit came a bracket that wraps around the cage for the upper attachment point.

I installed the retractable style, if I did it again I would install the fixed belts.   Passengers were knocking the covers off.  Somehow, one was actually lost.  
 

[Shadrach]

The belts are the same, the issue is the bracket.  I am not sure if/when the factory began welding seatbelt bosses to steel cage.  I have a 67F in which I installed shoulder harnesses 10 years ago.  The approved method of affixing the shoulder harness in the older birds is via specifically sized and molded steel collar (included with the Alpha kit). Your bird is 234 S/Ns before mine so you will need to use the same method.  Whether that method is compatible with the Ebay harnesses I can't say.  

It is nice to have a turn key kit.

The Alpha kit is a decent value but there are things I do not like about it:

+ All needed parts are included as are detailed instructions.

The factory belt clasps/buckles at least appear to be aircraft grade.  The Alpha buckle looks like it came out of an entry level ford product...from 1986...

The Inertia Real is high profile.  For this reason, it is best to install a manually tensioned belt on the passenger side to maintain a clean method of ingress and egress for the rear seaters. 

The steel tube to which the collar is mounted is against the fuselage skin and very close to the rear side window (which is attached to the fuselage skin).  To install, the collar must be be pushed between the skin and the tube.  I created a small crack in the rear pilots side window while flexing the skin away from the tube during installation.  Be very careful in this area. If I had a heated hangar, or had done the job in summer, it likely would not have occurred. 

[Yetti]

the F is a test bed for a J.  There is a clamp you need.

 

 

[canamex]

2 hours ago, Shadrach said:

The belts are the same, the issue is the bracket.  I am not sure if/when the factory began welding seatbelt bosses to steel cage.  I have a 67F in which I installed shoulder harnesses 10 years ago.  The approved method of affixing the shoulder harness in the older birds is via specifically sized and molded steel collar (included with the Alpha kit). Your bird is 234 S/Ns before mine so you will need to use the same method.  Whether that method is compatible with the Ebay harnesses I can't say.  

This is encouraging, thanks @Shadrach. After looking through @Yetti's post I'm a little worried that with my '66 made F model I'll also have those aluminum braces but I guess there's just one way to find out...

I did confirm that the seatbelts from the J model should work, just need to track down those clamps...

[canamex]

@Ron McBride this factored into my logic to go for fixed belts. Having flown with shoulder harnesses in Cubs for a year I'm used to the loosening/tightening procedures for T/O & Landing. Simpler typically is better in my books.

[Utah20Gflyer]

If you have the Johnson bar then be sure to get push button belts rather than the clam shell style as the latter get bumped and released rather often when putting the gear up or down,  at least they do in my plane.  That is on my list for a future upgrade to get rid of my clam shell belts.

I also have the fixed belts and prefer them, they are much lower profile and I don't find myself being bothered by the lack of give/play in them.  

[canamex]

@Utah20Gflyer the ones I'm looking at are just the regular belts with no quick release down by the Johnson bar...I'm guessing you have releases down there?

[Bunti]

I installed the Alpha shoulder harnesses in my 1967 M20F about 10 years  ago and highly recommend them. They work like a car seatbelt. Yes, the cover of the copilot belt sometimes disappears when people hit it with the body. It easily slips back on. A few years ago, I lost it. I called Alpha and the nice folks replaced it for free. Great customer service.

As long as your budget will allow for the new Alpha belts, I would buy them instead of  used or old ones. The material does not get better over the time and those belts are a real life-saver, if you need them. In case of a crash, they have do to a very hard job and you want them to it as good as possible.

Install took a few hours, but it is really worth it.

Here is a link to a study about the change of the safety belt material over the time,  done from EASA, the European FAA: https://www.easa.europa.eu/downloads/1232/en

[Utah20Gflyer]

3 hours ago, canamex said:

@Utah20Gflyer the ones I'm looking at are just the regular belts with no quick release down by the Johnson bar...I'm guessing you have releases down there?

My buckles for both seats are right by the gap between the seats, clamshell buckles facing down toward the Johnson bar, if you brush either with your hand bringing it out of the gap between the two seats the buckle releases.  Its a really annoying problem.  

[apriav]

Alpha has the kit to install shoulder harnesses, $22.

You can buy seat belts from Spruce, Wag Aero, or another aviation source. 

AC43.13 is liberal with seat belt safety improvements and lets you do it as a minor repair (log book entry only).

[canamex]

@apriav thanks for that, I just saw the kit on their website as well. Also on Aircraft Spruce's website. @bluehighwayflyer I read through the research paper @Bunti shared (well, the executive summary and the findings for 2000lb rated seatbelts manufactured prior to 1995 and the conclusion seems to be that those old seatbelts do not show major degradation relative to newer used seatbelts.

In any case, I'm probably going to go with the Alpha belts, if for no other reason than availability of support should something come up during installation (and maybe a custom color for the interior). Thanks for the input all!

[Hank]

8 hours ago, Utah20Gflyer said:

My buckles for both seats are right by the gap between the seats, clamshell buckles facing down toward the Johnson bar, if you brush either with your hand bringing it out of the gap between the two seats the buckle releases.  Its a really annoying problem.  

My clamshell buckles are pretty close to my own belt buckle when fastened. They were installed by the previous owner, and no J bar. Just realize that it's an option too.

[M20F-1968]

18 hours ago, canamex said:

This is encouraging, thanks @Shadrach. After looking through @Yetti's post I'm a little worried that with my '66 made F model I'll also have those aluminum braces but I guess there's just one way to find out...

I did confirm that the seatbelts from the J model should work, just need to track down those clamps...

I have a set of the clamps you mention, I just need to find them.  They were in a mid-60's E model that I took some parts from.  Then I came upon a 1998 Ovation  and proceeded to install the entire interior from that airplane,  including seats and seatbelts.    My installation  is likely not within your reach since the retraction reel  attachment plates are welded to the steel cage near the floor and the retraction reels are bolted to those plates.   I doubt you would be able to do that welding without the airplane disassembled.    I have the most modern Amsafe buckles  which require opening the top to  90° before allowing the buckle to release. I use these because a common problem in the vintage airplanes with a Johnson bar  is that the pilot bumps the buckle and accidentally releases the seatbelt  when the gear is put down.   The extra  throw of the modern Amsafe buckles  minimizes that problem.

I have some extra fixed seatbelts that use the most modern Amsafe buckles  which I may be willing to sell.   I'll take a look for the shoulder belt tube clamps since I know I have them...somewhere.

John Breda 

[skydvrboy]

Another option that if money is an issue is getting new belts from Hooker Harness.  They offer both fixed belts and retractable at just over half the cost of the Alpha Aviation belts.  The Mooney belts aren't listed on their website, so you have to call them, but they have what you need.  As of now, their belts are $275 for fixed belts and $475 for retractable.

If I were to do it again, I would get fixed for the passenger and retractable for the pilot.  I'd also ask for the pull tab straps to be added to the passenger side, it would be well worth the additional $5.

[Guest]

The clamp which anchors the shoulder belt goes around the steel tubular structure is an AN741 series, a -12 (3/4”) if I recall correctly.

Clarence

[canamex]

On 1/5/2022 at 10:54 AM, M20F-1968 said:

I have some extra fixed seatbelts that use the most modern Amsafe buckles  which I may be willing to sell.   I'll take a look for the shoulder belt tube clamps since I know I have them...somewhere.

Thanks John, would be interested in those seatbelts! Are the Amsafe buckles the clamshell type? Were you able to find those tube clamps?

[Guest]

From the J model IPC.  I was wrong about the dash number.

 

[canamex]

Thank you for finding that @M20Doc!