J model cowling retrofit?

[MQQNEY]

Is anybody able to advise me on the following:

I have heard that it is possible to switch out the original cowling on "C" models, which is supposedly inefficient, and creates drag, with the cowling from the "J" model, giving enhanced cooling, performance and economy. Is this true?

Edited September 29, 2016 by MQQNEY

[rbridges]

I have a C model with a J cowl. It can be done but I believe most of the conversions were done years ago. Given the cost of the cowling and modifications, it's probably cheaper to purchase a J.  Someone on this forum is developing a modified cowl for the vintage units that looks promising. 

[mike_elliott]

2 hours ago, MQQNEY said:

Is anybody able to advise me on the following:

I have heard that it is possible to switch out the original cowling on "C" models, which is supposedly inefficient, and creates drag, with the cowling from the "J" model, giving enhanced cooling, performance and economy. Is this true?

Yes it is true, and the design premise of why Roy Lopresti created the cowl for the J.

[KSMooniac]

Search up sabremech's cowl mod thread on this site...it will be far easier than doing a J cowl conversion.

Sent from my VS985 4G using Tapatalk

[DaV8or]

I think if you can get a good deal on the cowling and all of the parts needed, then do the work yourself, it could be worthwhile. I have thought of doing it myself. There are a lot of different parts required and I'm not sure how you handle the air intake connection to the C's carburetor as the J's cowling was designed for fuel injection. Somebody must have come up with a solution and you'll need to find that. I also think it may require the 201 windshield to be done as well, although I'm not 100% on that one. If you're hoping to buy the parts and then pay a shop to put it on, then I agree with others, you're better off trading planes.

[DaV8or]

32 minutes ago, KSMooniac said:

Search up sabremech's cowl mod thread on this site...it will be far easier than doing a J cowl conversion.

Sent from my VS985 4G using Tapatalk
 

Easier and more affordable yes, but no where near as good.

[jkhirsch]

What makes you say that Dave's cowling mod is "no where near as good?"

[Marauder]

I think the final determination of whether or not David's cowl is better or worse than an OEM 201 conversion will be based on several factors;

1) The actual speed gain of his mod versus the 201 mod. David is claiming a 6 knot increase on his C model. If you calculate his projected cost per knot increase, I think it will be more cost effective to go with his mod.
2) How well it holds up. The Achille's heal for his design is the robustness of the fiberglass add-on to the existing pre-201 cowls. Will it crack like what I see on so many 201s?
3) The "wow" factor. Honestly, unless you are gaining double digit speeds with a mod, the cost makes it ridiculous to do a mod. But if you can modernize the look of your plane, that has some inherent value.
4) Other performance gains. Will it help those doghouse owners with temp problems?

I'm waiting for Guitarman to have his F done. I want to see the speed gain. David already has me onboard just from the aesthics improvement over my guppie mouth.




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[carusoam]

1) Speed

2) CHT control

3) Access maintained

4) Modern looks

I'm looking forward to the owner feed back that comes in over time, followed by the expansion of airframes that get covered by the STC.

Go David!

Best regards,

-a-

[DXB]

Yeah definitely waiting on STC for Davids mod... speed, temps are the motivation.. Its look is more modern but that is not the driver

[Oscar Avalle]

II installed an ARI Cowling mod (There was a discussion in Feb 2010 on this subject).

https://aeroresourcesinc.com/proj98-ci/WebContent/product_category/view/9

I like it, the quality of the mod is good, the manufacturer is extremely responsive and it is easy to install. Now, in terms of speed gains, I have not tested and time everything out, but given that the CHTs are more manageable I can push the engine harder...

 

Oscar

 

[Yetti]

SWTA cowling

[Sabremech]

On September 29, 2016 at 10:00 AM, DaV8or said:

I think if you can get a good deal on the cowling and all of the parts needed, then do the work yourself, it could be worthwhile. I have thought of doing it myself. There are a lot of different parts required and I'm not sure how you handle the air intake connection to the C's carburetor as the J's cowling was designed for fuel injection. Somebody must have come up with a solution and you'll need to find that. I also think it may require the 201 windshield to be done as well, although I'm not 100% on that one. If you're hoping to buy the parts and then pay a shop to put it on, then I agree with others, you're better off trading planes.

I have the carb airbox you'll need to make it work. 

 

On September 29, 2016 at 10:02 AM, DaV8or said:

Easier and more affordable yes, but no where near as good.

Really? Mine retains most of the original aluminum cowling which has lasted much longer than the J cowlings. 

 

On September 29, 2016 at 4:43 PM, Oscar Avalle said:

II installed an ARI Cowling mod (There was a discussion in Feb 2010 on this subject).

https://aeroresourcesinc.com/proj98-ci/WebContent/product_category/view/9

I like it, the quality of the mod is good, the manufacturer is extremely responsive and it is easy to install. Now, in terms of speed gains, I have not tested and time everything out, but given that the CHTs are more manageable I can push the engine harder...

 

Oscar

 

Over the long term, you'll get tired of repairing the cracks that start showing up in the corners. I had the ARI before my mod and the cracking was one of the reasons I decided to do something different. 

 

23 hours ago, Yetti said:

SWTA cowling

Not currently available. It's a good mod and would like to see it available again. 

David

[DaV8or]

5 hours ago, Sabremech said:

Really? Mine retains most of the original aluminum cowling which has lasted much longer than the J cowlings. 

 

On September 29, 2016 at 8:11 AM, jkhirsch said:

What makes you say that Dave's cowling mod is "no where near as good?"

Sorry, I was not specific enough. In my mind, the main reason to alter the cowling on a vintage Mooney is speed gains. In the case of speed gains, David's cowling mod is not as aerodynamically slick as Roy LoPresti's  201 cowling. The later is a complete redesign and the former is a nice patch for a flawed design.

David's offering is no doubt cheaper and easier to install. It very well be more durable long term due to greater use of factory aluminum. You also get to keep your "cheek" panels which make for quick and easy inspection. However, the 201 cowl is superior in the speed department.

[jkhirsch]

Hey Dave you slightly lost me a bit, are you talking about the "LoPresti Cowl" or the stock "J model cowl?" I do understand that Roy was integral in the design process of the "stock" but it also varies significantly from his own "current" "LoPresti Cowl."

[rbridges]

I assumed he was talking about the stock 201 cowl. The lopresti cowl looks pretty cool to me, but I don't think anyone has demonstrated a true speed difference between the two. 

[rbridges]

As to the cracking issue, I just paid to have my fiberglass repaired and repainted. The metal that holds the baffling caused cracks to appear in the fiberglass. I guess the cowl vibrates during flight, and this caused some spiderwebbing to appear which led to paint flaking. I spoke with triple8 (Mike) last night. He had the same issues with wear and applied fiberglass to the underside every year. I added some rubber silicone strips and secured with aluminum tape to create a cushion for the cowl. Unfortunately the baffling is riveted pretty close to the edge of the metal and this limits vertical reduction of the metal.  

[Sabremech]

9 hours ago, DaV8or said:

 

Sorry, I was not specific enough. In my mind, the main reason to alter the cowling on a vintage Mooney is speed gains. In the case of speed gains, David's cowling mod is not as aerodynamically slick as Roy LoPresti's  201 cowling. The later is a complete redesign and the former is a nice patch for a flawed design.

David's offering is no doubt cheaper and easier to install. It very well be more durable long term due to greater use of factory aluminum. You also get to keep your "cheek" panels which make for quick and easy inspection. However, the 201 cowl is superior in the speed department.

My main reason was looks first, stop having to repair cracks in the ARI mod second, decrease CHT temps third, and if I gained any speed, fourth. Priority to me was in this order. If I purely was going for speed, I would have done something different, but then it would have been another unaffordable mod for a vintage Mooney. Mine is a compromise. It's not perfect but will be affordable for vintage Mooney owners to upgrade the looks of their airplane all while getting the engine a little cooler and gaining a little speed. 

I prefer to call it a mod and not a patch. 

Thanks,

David

Edited October 1, 2016 by Sabremech

[DaV8or]

9 hours ago, jkhirsch said:

Hey Dave you slightly lost me a bit, are you talking about the "LoPresti Cowl" or the stock "J model cowl?" I do understand that Roy was integral in the design process of the "stock" but it also varies significantly from his own "current" "LoPresti Cowl."

I mean the M20J cowl, not his refined aftermarket cowl. Sorry for the confusion.

[DaV8or]

1 hour ago, daver328 said:

Not sure those are available any longer ...

They're not. Production of those stopped years ago. According to Russell Stallings before he passed away, to restart production would require re-certifying the STC. Apparently the epoxy resin he used to make them is no longer available and using currently available resins require re-certification according to the FAA. He did not feel that it was worth the hassle. I assume the new owners of SWTA got all the STCs Russell had, so maybe they will pursue resurrecting the "201 Style" cowling mod. It's what I have on my plane and it is a nice solution, but even it isn't as good as the real 201 cowl aerodynamically.

[DaV8or]

30 minutes ago, Sabremech said:

My main reason was looks first, stop having to repair cracks in the ARI mod second, decrease CHT temps third, and if I gained any speed, fourth. Priority to me was in this order. If I purely was going for speed, I would have done something different, but then it would have been another unaffordable mod for a vintage Mooney. Mine is a compromise. It's not perfect but will be affordable for vintage Mooney owners to upgrade the looks of their airplane all while getting the engine a little cooler and gaining a little speed. 

I prefer to call it a mod and not a patch. 

Thanks,

David

And I agree that your mod will be a great option for future vintage Mooney owners. At this point it is mostly just about cost. The value of M20Js has come down so much that spending much money trying to make a vintage Mooney into a J doesn't make any sense anymore. The vintage Mooneys are finally becoming obsolete and going to the scrap yard like their original creators had intended them to do decades ago, it's just things move slow in aviation.

[Sabremech]

13 minutes ago, DaV8or said:

They're not. Production of those stopped years ago. According to Russell Stallings before he passed away, to restart production would require re-certifying the STC. Apparently the epoxy resin he used to make them is no longer available and using currently available resins require re-certification according to the FAA. He did not feel that it was worth the hassle. I assume the new owners of SWTA got all the STCs Russell had, so maybe they will pursue resurrecting the "201 Style" cowling mod. It's what I have on my plane and it is a nice solution, but even it isn't as good as the real 201 cowl aerodynamically.

I don't think this would be as difficult as they think it would be. As involved as I am in FAA/PMA and STC's, I think it would be easier to do than getting my mod to certification. I offered to buy the SWTA cowling mod several times. Mine is definitely about the cost versus reward for our old birds. If I break even at a minimum after getting it certified, I met my goal. Of course I'd like to make a little money so I could move on to the next mod. 

 David

 

[N601RX]

I found  a 201 cowl and baffling a few years ago for $700.  A little later I found a freshly overhauled engine mount for $200 and spinner for $400. The FSDO seems receptive to doing a field approval and I've also talked to a DER with structural and power plant authority who will approve it. Doing the work myself I should have less than $2k involved when finished. 

The 201 cowl looks nice, but I also really think I will miss the easily removable side panels.  That's the nice thing about the swta and David's is that they keep the side panes.  

[DaV8or]

2 hours ago, bluehighwayflyer said:

You did well, Mike. Being able to drop the entire bottom 201 cowl in a few minutes more than offsets the loss of the cheek pieces. You won't miss them too much, I think. 

Jim

Yeah, the cheek panels are great for a quick inspection, but other than that they aren't of that great of value. Being able to drop the lower cowl easily is well worth the trade off IMO.

[Sabremech]

3 hours ago, bluehighwayflyer said:

You did well, Mike. Being able to drop the entire bottom 201 cowl in a few minutes more than offsets the loss of the cheek pieces. You won't miss them too much, I think. 

Jim

I have to disagree on the cheek panel comments. I can remove my top cowl and cheek panels and do almost all my maintenance without removing the lower cowl. 

You risk damaging your lower cowl on the J or even my C every time you remove it. I personally think it's easier to remove the lower cowl on the airplanes with cheek panels as the lower cowl is smaller and easier for one person to handle. 

As an A&P those panels are priceless to me. 

David