How well would a Mooney do in a hard landing?

[chrisk]

I just saw a video of NASA doing some hard landing tests on a 172.  https://www.youtube.com/watch?v=Kx5YeqTBcDI  It was amazing how well the landing gear took the energy.  I wonder how well our Mooneys would do?  I have visions of the landing gear being pushed through the wing.  --Not that this really matters, as long as the folks inside are ok.

 

The video also convinced me shoulder belts are really worth it.  --I'm glad I switched mine out to the auto style retractable.

[peevee]

it'd do just fine, so fine in fact it'd be right back up in the air and flying immediately after the bounce.

[pinerunner]

One of the things the Mooney isn't famous for is rugged landing gear. Its relatively simple to maintain if you don't mind spending a grand for a bunch of hockey pucks but its very stiff. As a short field exercise I went into an airport in Maine (Twitchell's) that I knew well for almost my whole life. I had flown a 172 there a couple months previous working toward my biannual. When I touched down I started hearing (and feeling) a bang, bang, bang.  Every seam in the runway which I had never particularly noticed before. Despite my desire to show off my "flying Porsche" I've never gone back there. At the smoother airports I've been flying into I've never noticed just how stiff the Mooney gear is. So I'm sure if you start dropping it hard on the mains it's not a good idea. Despite what some others have said it probably speeds up the formation of fuel leaks. Our tough wing structure can't be completely rigid; there has to be some flex. Drop it hard on the nose and get a prop strike; you gotta set down on the mains.

 

It's one of the things those B-plane owners trumpet about as an advantage of their utility planes with rugged landing gear. I didn't get my Mooney to be a bush plane. I wouldn't be afraid of a grass strip but I'd be very picky about which one I went into.

 

Mooneys are for pilots.  

[clh]

lol +1 on the it is not possible to do a hard landing...  

 

Seriously, I have seen pictures of where the landing gear was punched up through the wing.    Since there is less travel in the gear, I would think a "dropped" Mooney would likely provide a faster deceleration to the ground. 

 

The nose gear looks like it will fold back or collapse and the cowl/engine would fold back similar to the cessna. 

 

Also, Mooneys would just look better when they crash\

 

To Pinerunner:  How old are your biscuits?  When I changed mine, the ride significantly improved.  Still much stiffer than the brand C or P,   

[pinerunner]

lol +1 on the it is not possible to do a hard landing...  

 

Seriously, I have seen pictures of where the landing gear was punched up through the wing.    Since there is less travel in the gear, I would think a "dropped" Mooney would likely provide a faster deceleration to the ground. 

 

The nose gear looks like it will fold back or collapse and the cowl/engine would fold back similar to the cessna. 

 

Also, Mooneys would just look better when they crash\

 

To Pinerunner:  How old are your biscuits?  When I changed mine, the ride significantly improved.  Still much stiffer than the brand C or P,   

I'll have to check my logbook to be sure since the bisquits were changed when I had my first annual. No other airport has given me the little jolt when I crossed a seam and I only have felt it at that airport with the Mooney.

[Shadrach]

I disagree on the lack of ruggedness. I think these planes have hell for stout gear components if properly maintained. They certainly are not plush, but I believe would tolerate far more abuse than most would think. I've had mine in and out of several turf strips that are far from smooth without problem. I do not subscribe to the notion that landings will cause fuel tank leaks; I'm sure they can cause leaks, but if you've hit hard enough to cause a leak, then you've likely bent your airplane.

[N33GG]

Just like the price of annuals, there is no reasonable comparison between an Mooney and C172 when it comes to hard landings.  Dare I use the word significant????  Yes, I will.  There is such a fundamental difference in design and hence capability given fixed spring gear vs. many moving mechanical pieces that have been designed given the compromise of weight against adequate robustness.

 

IT'S SIGNIFICANT!

 

[kmyfm20s]

Our gear might be rugged and simple but it comes at a price of not have much travel and a high rebound rate. On a ruff field it bottoms out and rebounds you back into the air. That's where other more complicated gear has the advantage.

[pinerunner]

To be fair to Cessna the old spring steel landing gear was famous for it's ruggedness. My dad (a bush pilot) told of seeing a 180 land so hard that the steps plowed little furrows in the grass strip and the gear came through OK. Nose wheels not so much and my dad's last rebuild project, an older 182,ended up wiping out nose gear on a gravel bar in Alaska.

 

Tough and hard aren't the same thing and you need a little give to be tough and last through abuse. I do believe that sharp, sudden, flexing of the wing can loosen up sealant in our wet wings. The plane we used in our seaplane service eventually needed an airframe overhaul (you don't see that talked about anymore) and that included drilling out and replacing rivets that had worked loose. A seaplane has no shock absorbers per se and depends on the squishiness of the water which can get kind of hard at take-off speed. A little dark ring, showing up through the paint around a rivet, is a tell tale for this. I looked for that when I was shopping for my M20E. It clearly had had an easier life than the old seaplane.

[Shadrach]

It's my opinion that any sealant that separates or "loosens" in/from the tank has already been compromised by age.  Have you ever handled the stuff after it has cured? It is far more flexible than the Mooney wing.  Your seaplane analogy is well taken, but I don't think it really applies.  I've actually taken expired PRC, mixed it up and smeared a glob on a piece of sheet metal. I assure you that no amount of flexing would compromise the bond.  I still have a tube or 2 left of expired sealant just begging for an experiment.  What do you think would be a good way of testing?

[Yetti]

Mine seems to do pretty good in a hard landing.  Eventually I will get it to be smooth

[BigTex]

Comparing any retractable gear plane to a fixed gear trainer is really apples to oranges.  One is designed to withstand pilots that prang it onto the runway and one isn't.  You could also carry this discussion to military aircraft like F18 vs. F16.  The F18 is designed to take some seriously hard carrier landings and the F16... not so much.

[N601RX]

There used to be a guy on ebay who worked for a NASA contractor and sold expired tubes on ebay for a couple of $ each. I got several tubes from him just use around the house.  I've used it on non aviation stuff 4-5 years after it expired and could not tell any difference. There is a blob that has been on the outside of my galvanized hanger door for the last 2 years and I can tell that it has aged some from the very hot metal and sun exposure.

[carusoam]

Ross,

Possible ideas for home grown test methodology...

Typical polymer physical test...

Tensile test.

Make a sheet of the rubbery material.

Cut it into a nice rectangular bar shape. 10" X 1/2" x 1/8”

Hang it from a clip at one end.

Use another clip to hang a weight.

Measure the extension of the material compared to the weight.

If the material doesn't stretch, add more weight until it starts to stretch (yield).

The official test for this uses an ASTM standard and expensive machines...constant strain rate and constant stress.

A really interesting test would include the adhesion strength between to pieces of aluminum...

Using two pieces of aluminum glued together with an offset. Hang the assembly by one piece and attach the weight to the other piece.

Add weight and temperature (and fuel?) until the sealant fails...

X polymer guy, not much of a tech writer...

Best regards,

-a-

[N33GG]

Comparing any retractable gear plane to a fixed gear trainer is really apples to oranges.  One is designed to withstand pilots that prang it onto the runway and one isn't.  You could also carry this discussion to military aircraft like F18 vs. F16.  The F18 is designed to take some seriously hard carrier landings and the F16... not so much.

 

When I graduated college in the '70s, I interviewed with McDonald Douglas before accepting a job with General Dynamics.  MD was testing the F18 with a drop test when I was there.  They would lift it up about 20 feet (don't remember exactly how high, may have been a bit more or less) and then drop it on concrete.  This was repeated until something broke, notes made, and the test continued.  It made a real impression on me. 

 

Years later, I was designing field test equipment for telephone companies.  I had my engineers go on top or our 4 story building, throw the equipment up as high as they could, and let it hit in the parking lot.  We did this until something broke, changed the design, and continued.  The phone companies were in awe when our marketing guys would take our equipment out in the parking lot and throw it up without blinking.  It helped make us very successful.  Thank you McDonald Douglas!

[pinerunner]

Comparing any retractable gear plane to a fixed gear trainer is really apples to oranges.  One is designed to withstand pilots that prang it onto the runway and one isn't.  You could also carry this discussion to military aircraft like F18 vs. F16.  The F18 is designed to take some seriously hard carrier landings and the F16... not so much.

 

A sensible point. The comparison that comes to mind then is the Bonanza. Maybe the old Piper Comanche too. The Bonanza has quite a reputation as a fast plane that's rugged in the utility category and has very rugged landing gear. I think its heavier and needs more horsepower to get the same performance as a Mooney. 

[ryoder]

It's my opinion that any sealant that separates or "loosens" in/from the tank has already been compromised by age.  Have you ever handled the stuff after it has cured? It is far more flexible than the Mooney wing.  Your seaplane analogy is well taken, but I don't think it really applies.  I've actually taken expired PRC, mixed it up and smeared a glob on a piece of sheet metal. I assure you that no amount of flexing would compromise the bond.  I still have a tube or 2 left of expired sealant just begging for an experiment.  What do you think would be a good way of testing?

When I had my tanks resealed I asked if I needed to put new biscuits in to avoid leaks. Both my home IA and the IA shop owner that did the reseal said no way that would happen.

[MyNameIsNobody]

But it sells a lot of $1000 biscuits...

[bonal]

Just thinking,  when aircraft are going through the certification process don't they drop them onto the extended gear to test for really hard landing performance and if so Mooney's would have had to pass the same tests.