Thursday, April 24, 2008

Mooney Construction versus the Competition

I find it interesting that Cirrus is building plastic (err. composite) planes with life-limited airframes and then they try to convince the public that their product is superior to a Mooney. Yes, that’s right; the Cirrus and some other composite airplanes have a 10,000 hour or finite life limit of some-sort on the airframe/wings. When you reach the time limit on the airframe it is grounded forever. The sales reps say 10,000 hours is practically forever, so it isn’t a big deal. In reality they are probably right. Composite airframes simply will not hold up in the sun, weather, etc. as well as the tried and true metal airplane. They will likely be long gone before they ever see 10,000 hours.

I’m sure my first paragraph will not bode well with our composite friends, but the truth of the matter is they have spent good money on an airplane that will not withstand the test of time. There are many Mooney’s out there with thousands of hours and are going strong at 50+ years old. A metal airframe will pretty much last forever if it is given reasonable care.

As a previous Cirrus SR22 owner, I’m willing to bet that there will not be many Cirrus, Diamond, etc. airplanes that make it to 50+ years old. Certainly not as many as there are Mooney, Beech and Cessna's. There are two primary reasons I make this claim: 1) Composite materials cannot easily be refurbished and they break down under stress; 2) mechanics in the field do not have the skills or equipment to properly inspect these structures or access to the facilities required to repair them. Sadly, many of these planes will likely be scrapped over time and the owners will suffer through huge depreciation losses as savvy buyers start to figure this out.

Accordingly, the fit and finish isn't there either. Simple parts like $1200 nose gear fairings that crack after one somewhat hard landing; $1500 cabin door pins that bend in seconds if someone closes the door wrong preventing the door from latching; technological upgrades are very difficult, if not impossible, due to the way they formed the instrument panels; you can't refurbish a composite airframe like metal, so nicks and dings will be a fact of life for these owners...

I'm sure there will be owners like me who are meticulous, but I'm talking about the masses. I've seen Mooney's that sit on a ramp their entire life and even have suspect maintenance, yet they are still airworthy and going strong. This will not be the case with the plastic planes. Of course, the NewCo's know this. They don't want them to last forever. They want to sell new planes, not maintain old ones. In the auto industry they call this planned obsolescence.

The Composite Airframe
Before the critics start throwing stones at me…No I am not making this up. The FAA test data supports this fact. The Cirrus Type Certificate is an excellent example. Not only do they avoid spin certification by using a parachute that if used will kill the airplane, they also can’t paint their planes! Or I should more accurately say they can only paint 20% of their plane. 80% of the bird is legally required to be white. Why? Because heat is not the friend of composites. They need to be painted with highly reflective paint to keep the surface as cool as possible or it will start to cure again and weaken the structure. So much for parking on the ramp!

Can't do this paint job on a plastic plane!

Mooney Construction
I recently visited the Mooney factory in Kerrville, Texas. I can honestly say I walked away with more respect for these birds than I had before I arrived. Composites are simple quick builds, which is cheaper and faster to construct. Mooney’s are not quick builds. The labor that goes into creating these planes is remarkable. Every airplane is literally custom built from the ground up out of aluminum sheets and steel tubes.

The core of all Mooney's is the safety/passenger cage. This is a steel tube constructed roll cage that completely surrounds the passengers. This structure not only makes the plane safe, it also makes the plane strong. Very Strong!

Take note of the triangle shapes built into the cage. A triangle creates the strongest possible man made structure. This cage is why there are very few fatalities in Mooney accidents. The NTSB reports clearly show that if you land somewhat under control in a Mooney, the chances are you will walk away.

The next key structural component of a Mooney is the wing and spar. Unlike the plastic airplanes that have a plastic laminated spar, the Mooney has the strongest spar in the industry. This is why there are very few, if any, in flight breakups of Mooney's. In fact, I've heard stories of pilots that have flown into severe T-Storms and back out the other side with virtually no damage to their airplanes. I don't recommend flying into a T-Storm, but if you did so in a Mooney you'd probably survive and be darn glad you weren't flying a plane with a plastic spar!

Now that's a wing!

I challenge you to look very close at the above pictures and give serious thought to how strong and safe the Mooney is. Then think about how much stronger it all is when it is held together with rivets and aluminum.

And if strength or safety is not your thing, speed may be. The Acclaim S is hands down the fastest GA airplane out there at a 237 Knots cruise speed! Or if speed is not your thing, maybe it's efficiency. You can go farther on less fuel than any other comparable GA airplane out there... Oh yeah, insurance and maintenance is also less expensive...

We Mooney drivers are very fortunate to have such an incredible and capable airplane. We are so passionate about our birds that we even have a name -- Mooniacs. We all honor and respect Al Mooney because he put his heart and soul into designing this incredible M20 airframe. And we are all benefiting form the fact that he engineered them to last forever. And they often do. 252Q has already outlived one of its owners and she's well on her way to outliving me!


Anonymous said...

Interesting post, and for the most part, I agree with you. A couple of points though...

First, the Cirrus, AFAIK, is the only composite airframe with a specified time limit. Diamond aircraft do not share this limitation, and I'm not sure about other composites.

Secondly, I understand the mooney wing spar is incredibly strong. So how is it mooneys are not utility rated to gross weight like most Beech aircraft?

Jim Kerr said...

You are right about the Diamond time limit. They do not have one set by the FAA. I found this comment about Diamond safety on the web that I thought was interesting:

"Either of the DA40's wing spars can carry the full load of the wings, thus leading to the FAA certifying the composite airframe with no life limit. Composite materials are not subject to metal fatigue and therefore a mid-air break-up seems virtually impossible."

What I thought was funny is they say it "seems virtually impossible." Further, they are certified to carry the certified G-Load. When you go through a T-Storm our severe turbulence you can significantly exceed those limits and brake your airplane!

The composite crowd often talks about Aluminum flex as if it is a bad thing. As an Aeronautical Engineer, I can tell you it is not a bad thing -- it's good. Metal naturally flexes and returns to its original shape. It can also flex well beyond its limits and hold together. Composites fracture when they hit max load. Trust me on this one, if you ever see a destructive test of a composite spar it will scare the hell out of you. It holds for a bit and then - BAM! - it breaks into a million pieces. In other words, you have a chance of limping a bent metal plane home, not a composite. Hawaii Air with the roof completely missing comes to mind. If that plane was composite it would have likely broken up in flight.

To answer your question about the Utility Category limit, it is pretty simple aerodynamics. Mooney's have a laminar flow wing design and the Beech have a NASA wing. Mooney wings are built for speed while the chord of the NASA wing is built for max lift. Aerobatics at max gross weight can bend the wing tips of a Mooney throwing off the rigging. The spar has nothing to do with it. The plane will not break. It simply may not fly true and correct if repeated utility stresses are loaded up on the wing rigging points.

This difference is obvious when you look at the two planes head on. The Beech wing is thick and the Mooney wing is thin. To that end, Mooney was designed for distance travel and efficiency, not aerobatics. Beech was designed for max payload, which coincidently enables them to sustain utility category certification up to max weight.

Aircraft design is a give and take. If you want lots of room and payload, buy a 206 or Bonanza and take your time getting there. If you want to go 200 knots on 13 GPH, buy a Mooney.

Anonymous said...

My 201 has a little over 10,000 hours on it now, and it literally looks and flies like new. Proper maintenance, regular Corrosion X treatments, and hangaring are the keys. It'll be around long after I'm gone, and if subsequent owners continue to hangar and properly care for her, total airframe time will, for all intents and purposes, never be a factor in her survival. Great site. Keep it comin'.