The Mooney Porsche

[daepp]

Anyone know much about the Mooney with the Porsche engine? I'm curious, did they use something like the twin magnetos like a general aviation airplane? And what about the 911's dry sump - do airplanes have dry sumps?

Saw a Mooney fly over me in Fullerton and it got me to thinking - I had heard of this Porsche engined plane long before I knew much about a 911 - now the details got me wondering!

Are any still in use? Was it a good plane? In general, aren't automobile engines frowned on in airplanes?

[Porsche-O-Phile]

Last I heard Porsche was trying like crazy to buy back all the remaining ones out there because they don't want to have to continue supporting them with technical bulletins, parts, etc.

Very neat aircraft though. . . I have a bunch of time in M20s (not the Porsche-powered ones) and absolutely love them. Fantastic aircraft, very quick and lots of "bang for the buck".

[slodave]

They perform better with a Steve Wong chip.

[k9handler]

off subject but I once heard the Mazda rotary made a good aircraft engine.

[MT930]

It was a real nightmare for both Mooney & Porsche. Great concept, sexy airplane I have not seen one in years. I think most have been retrofitted with Continental engines. The Mooney's with out the P engines always reminded me of air Porsche light & fast with quirks. You can't put to much in to them, but they perform well.

[daepp]

Dry sump?

[URY914]

[Bob Goding]

If I remember correctly, our Host ,Wayne had some aircraft Porsche cylinder heads at one time? Theres a chapter on it in "Porsche 911 engine history and development " by Tobias Aichele[but dont rush out and buy the book, its not worth the money IMHO]
The spec was/is PFM3200.

[John Rogers]

Did you know that some of the blimps years ago used to use Porsche 930 Turbo engines? Power and reliability the blimp folks said.

[slodave]

Originally Posted by Wayne at Pelican Parts

I'm not sure what they did about the oiling system, but I'm pretty sure that these engines were wet-sumps like the 911s.

-Wayne

Wayne,

Check out the spec page two posts up. It says dry sump.

Dave

[9dreizig]

according to my paperwork, I shipped my 930 engine in from Germany ( bought from Harald- Speedster94) in as "experimental aircraft engine- used" saved alot of paperwork and taxes.. LOL

[Laneco]

Okay, now I want to see one painted in Gulf or Martini livery...

Now THAT would be a cool plane!

angela

[URY914]

[Dantilla]

It's purchase price was much higher than the standard Mooney, and it offered no better performance. Thus, not many were sold. Its big advantage was a single power lever, instead of the three (throttle, propeller, mixture) used in most airplanes.

The downside was excessive cooling drag. Using a fan just like the car was supposed to keep the engine temps more stable than simply using airspeed over the cylinders. The air exiting the engine compartment was so turbulent under the belly that the Porsche powered Mooneys didn't have inboard gear doors. It was determined that they would not increase speed, they would just add weight and complexity, so they were eliminated.

I remember hearing that some Mooney engineers were frustrated at the Porsche engineers, because they would not listen about their concerns- The Porsche engineers thought they knew all there is to know about air-cooled engines, and ignored any discussions about cooling drag.

[pwd72s]

Originally Posted by URY914

Be careful...you'll see this pic, slightly modified, on ebay soon...

[URY914]

That will be OK with me, I didn't take it.

[304065]

The best critique of the PFM is here: http://www.seqair.com/Other/PFM/PorschePFM.html

An excerpt:

The one absolutely horrible design feature is the fan cooling system. While it only uses a couple of horsepower to drive the fan, it totally destroys the exit velocity of the air. In normal installations, the engine acts as a radiator and the heat expansion of the air drives it out of the engine compartment. This thrust keeps the cooling drag to a minimum. One engineer estimates that the Porsche Mooney is losing 12-15 knots from the fan cooling.

Porsche claims that the engine is efficient, but this is statistical mumbo-jumbo. At best economy, Mooney's Lycoming and Continental engines are more efficient, but brake specific fuel consumption does not account for the extra drag of the cooling system and the bulbous cowling. These steal power from the installation. The faster the airplane, the greater the net power loss. The extra weight steals from the payload. What counts is moving payload efficiently. Watch the CAFE 400 for a true measure of the engine's efficiency.

It is now well understood that listening to customers and understanding their needs, desires and problems is of critical importance to the success of any commercial venture. In a Kendo blow of incompetence, arrogance and stupidity, Porsche did not talk to the major light aircraft companies before designing the engine. It's often been said that Porsche has forgotten more about engine design than aviation engine manufacturers ever knew. Porsche mistook a compliment for the truth and never bothered to find out the few things that Lycoming and Continental did know.

Had they asked, they would never have designed the silly three-point engine mounting system with one of the pickup points on top of the propeller gearbox. This makes for an awkward and complex engine mount, which on most singles also picks up the nose gear. It is difficult enough to design a tubular steel structure which will reach over the engine, but you must also provide some means of removing the engine. In the Mooney installation, the engine is trapped between the nose gear and the complex tubular structure which reaches out over the engine. You tilt the engine nose down and then take it straight forward. You can't use a block-and-tackle hoist, but Porsche has a special gizmo designed for that purpose.

Had they asked, Porsche would also have discovered the addiction to four engine mounting points-one more than you need to fly. If you lose one of the Porsche mounts, the engine is going to go bye-bye. (I have a friend who actually broke two of the four mounts on his Baron. On that airplane, the mounts are all on the bottom, so the engine continued to sit on the totally-cracked-through castings.)

Seriously now, the biggest problem with this engine is that it used a cooling fan, and I dont' mean the big one up front! (The prop is a fan to keep the pilot cool-- if you don't believe me, turn it off in flight and see how much he sweats)

Here's a photo. See the flange where the prop mounts?

Now see the fan at the other end? WTF?



What were these guys thinking, were they taking a page out of the BMW 801 playbook?



Hmm. . . something a little familiar about that fan. . . did these guys all study from the same engineering texts or what?