Sabremech

Vintage Mooney Cowling Mod

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I thought I would start a separate thread to document the STC process for my Mooney cowling mod. I welcome questions as I show and detail the project.

 My intent is to update the look of the older Mooney cowlings, namely the C,E,F, & G models. Certainly performance gains would be nice and I hope to report any increases once I'm flight testing the prototype cowling on my 66 C. My cowling will incorporate round air inlets for the cylinder cooling air and carburetor air on the carbureted engines. I will be keeping the plenum system as I feel it's the most efficient system for cooling the cylinders. It will also include new baffling. Some of you may recognize the parts I'm using as coming from James Aircraft. They are fantastic to work with and have supported me with parts I need for my STC.

 

 This project is being done through my company called GDS Aero. I merged my other company (Vintage Airworks) into GDS at the end of 2104. No sense having 2 FAA quality systems to  manage and 2 separate audits each year.

 

 

 On with the pictures:

 Here's a couple of pictures of the plenum and new baffling being made.

 

 

post-7497-0-26306700-1424381339_thumb.jp

post-7497-0-38484000-1424381366_thumb.jp

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Is this to replace the doghouse found on some models?

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That looks great! Probably much more effective and efficient at cooling, too!

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 This will replace the doghouse baffling found on Vintage Mooneys. It will come with the STC kit.

 

 David

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David,

Are you going to make a new nose bowl to adapt to your air plenum?

Clarence

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Hi Clarence,

I will be making a new nose section that will rivet in to a factory seam on the upper cowl and yet to be determined on the lower cowl. I'm primarily working on the plenum and baffling right now. The cowlings are in my shop where I can study the changes I want to make.

David

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This will replace the doghouse baffling found on Vintage Mooneys. It will come with the STC kit.

 

 David

Hurray!! I've repaired my doghouse the last three annuals. I'd love to get rid of it!

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There looks like three strong advantages could be available for the C...

1) Improved cooling... The dog house in the 65 needed some help.

2) Improved exterior aerodynamics... In 65 the cowl was a big square block

3) Improved image... Something like the O or Acclaim would interesting...?

Interesting project progress David.

Best regards,

-a-

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When can we order? :)

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What is the target retail price and number of hours to install?

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I'll take orders when I have the STC paperwork in my hands! Target price and hours to install will be determined closer to having my airplane done as the prototype.

David

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But you need to have a business plan right? Ten thousand? Five thousand? Sell one thousand units per year, recoup fixed costs by two years, make 1k per unit sold in marginal profit by year three, average an internal rate of return of X... Etc.

Good luck to you. I don't have the balls for entrepreneurship.

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Hi David,

 

Are you reducing the inlet area/size on  pilot side  of the dog house baffling ?  I haing trouble  keeping the cylinder temperature on cylinders #2 &#4 cool on take off on occassion I have had them above 450d F on take off during climb out. It seems that the inlet on the Pilot side (Cyl #2 & #4) has a larger  area when compare to  inlet area on right side (Cyl #1&#3 ) . In my case I suppect  that there is turbulent flow in the  the dog houes  baffling since area is so wide open. 

 

  I hope this  finially that thus resolves  cylinder head temperatures  plaguing several of us out there. Thanks for taking this project on. It  is something that  I am interested in.

James

'67M20C

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Why not move the oil cooler back and replace it with a redundent landing light and/or taxi light as part of the STC. Build the mount for the oil cooler right into your plenum. Maybe change both lights to 36 style LED since no STC's for 42s seem to be coming. I know project migration / stay focused. But.

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Another problem common on the 180hp models is the poorly designed carb induction box & boot.  It transmits way to much engine vibration into the lower cowling section.  Rarely do you see a 180hp Mooney without patch work around the numerous openings - (light, carb opng, oil cooler)  the vibration also eats up carb heat boxes, and cowling flaps, not to mention the rubber boot.  Some airplanes, the boot is attached to the carb heat box with a doubled up hose clamp and the lower clamp has actually worn a hole/groove into the lower cowling.  Best of luck.  The James do fantastic work.  So, have you gone thru the STC process, before?  I don't think the overall shape of the cowling is going to be easily improved without some kind of prop extension and that will drive the FAA guys into a state of hyper anxiety.

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Time to answer a couple of questions posed.

Ryoder: business plan, mod my airplane by completing STC. Price reasonably to sell a good quantity. Recover the cost of STC at some point, hopefully in the first year. Goal is to break even and have my airplane the way I want it.

Jamesm, the air inlets will be the same size for the cylinder cooling on both sides.

Steve65E-NC, oil cooler stays where it is. Moving it will cascade to many other parts being moved for little gained in relation to cost.

Mike20papa, I have done the STC process and hold FAA/PMA. I think the cowling can be improved sufficiently enough without a prop extension. It is going to require a 201 style spinner.

David

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This looks promising!

The engine cooling on my C in the climb segment is problematic at best.

Will it give my C another 5-10 knots ?

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Hi Daver328,

I won't make any claims or promises at this point. I'll have some real numbers when I start flying with the mod early this Summer.

Price can't be set until I know what it costs me per kit in parts cost, then I can set a price. I'm aiming for as economical as I can due to the value of our airplanes.

David

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I don't believe the "doghouse" baffling was used on any F models; I know my 67 F does not have a doghouse. Will your mod adapt to aircraft without the doghouse?

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David, glad to see the progress you're making.  I've followed your past threads with a lot of interest.  

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Sreid,

Yes, the E & F mod will include the plenum and new baffling.

Rbridges,

Thank you.

David

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Hi David!! Any thoughts about using the stock (non 201) spinner? I have thought about getting a 337 done to have the top of the doghouse brought fowdard to enclose the area behind the spinner. This would clean up the rough air, and you could even keep most of the cowl, encorporate the lower cowl closure if you wanted etc. Similar to a late 70's 182 or somthing like that.

Nice work, stay warm!

-Matt

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Hi Matt,

I haven't really thought of that. I have the 201 spinner on mine already and like it. I do need to find a source to supply the spinner so that could dictate a change.

Trying to stay warm, but hard to do this year!!

Take Care,

David

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Hi Matt,

I haven't really thought of that. I have the 201 spinner on mine already and like it. I do need to find a source to supply the spinner so that could dictate a change.

Trying to stay warm, but hard to do this year!!

Take Care,

David

I'm in the same situation. I was nearly ready to buy the ari cowl for my 67F, but realized I would have to get the 201 spinner and backplate. The extra cost of those put the whole idea out of my head. Hope you can make this work with non-201 spinners! ;)

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Is this a completely new cowl top and lower, or just the top half and baffles? If you're doing the lower, are you going to do a new Ram Air system like Lo Presti did? What about gear doors and cowl flaps? How much have you looked at Lo Presti has already done?

 

Looks good so far and keep up the good work!

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