Blue on Top
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@Austintatious Exactly! … but that is not the mindset of people that fly with them. And to repeat what @cliffy said, "We tend to forget (or never hear of) all the forced off airport landings that happen every year without any serious injuries" and in my opinion are never (or seldom) reported. This is my point exactly that parachutes may have "saved" 237 people, but the 1000s of people that have landed off airport or on airport after a failure are not published, documented or on TV. Thanks, everyone!
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@carusoam Is there an STC for these shoulder harnesses to be installed in your Mooney? Before you purchase, you might want to read what the NTSB has to say about air bag shoulder harnesses. All that glitters is not gold. Plain shoulder harnesses have proven time and time again to save lives. If your airplane doesn't currently have shoulder harnesses, I highly recommend them. Remember that Mooneys were designed long before HIC requirements (Head Impact Criteria (… and 26G crash seats, too). One large advantage of having a side stick (M10) is that it opens up more panel space for an air bag that won't conflict with flight controls. My 2 cents, Ron
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Oops! My apologies to both @PT20J and @carusoam. No excuse. You're both awesome!
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Vertical Gs on a normal landing are very low (<<1G). Landing gear is designed for 3G maximum before failure. I believe that 3G is in the range of 10+ fps (600 fpm); similar to a carrier landing. That's why carrier aircraft landing gear (and fuselages) are VERY beefy. It is also why you'll see the gear move up and down a lot (so that load is not transmitted to the wing/aircraft). As for longitudinal deceleration, I have seen higher than 0.3G (rubber to concrete friction can only go so high … even with anti-skid brakes). If your brakes can hold your airplane stationary with full power ...
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@Hank The Bo gear is also all one mechanical operation. In an emergency, the gear is lowered with a single crank (50 turns).
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Regretfully, the full aircraft parachute will never go away … as long as Cirrus is making more airplanes than anyone else (which might be coming to an end before long). So, and responders will have to qualify their comments by aircraft body length, how much useful load is one willing to give up (and maybe a couple knots and maybe a little cosmetics) to add a parachute to their Mooney? And how much initial cost and recurring costs is one willing to give up, too. Nothing is free, but I know it can be done better than what is currently out there (experience is priceless … not free, though). In essence, is a used airplane with a full aircraft parachute worth as much as a new aircraft with a full aircraft parachute? I am guess that this topic has be brought up a "few" times before, but ... Here goes. … Pull!
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@carusoam I will say that this would be closer in weight, but the additional weight for a parachute is the parachute plus the added structure plus the added bump on the outside for the parachute risers. Keep trying … maybe eventually. Seriously, how much useful load are you willing to compromise? This sounds like a new thread to me
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There is a really, really simple solution to these three pages of discussion. Fix the gear down … and don't bring up the "D"; it was not designed as a fixed gear airplane. Yes, you might lose 10 knots (at worst), but you will also lose a lot of weight, a lot of complexity and a lot of maintenance. And, with all the weight that is saved, you might be able to carry all the insurance and maintenance money you saved on your next vacation. … just sayin'. PS. And no Mooney owner has ever complained about the non-edible donuts.
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Thanks, @Mooneymite. Also don't use the strength of steel when you're building aluminum spars. … Google Curtiss-Wright X-100; zoom in on the wing. You'll see a steel cable strut from the bottom of the fuselage to the outboard wing. Seems the wing bent up a little more than planned on the first engine run
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@carusoam Bummer on this one, but you're correct. 1) Upping the horsepower isn't always the right way to do things. Matching the HP at a lower weight and cost is. 2a) Ironically, with today's regulations, the wings on small airplanes are designed for gust loading (and not maneuver loading … 3.8G, typically … plus a 50% safety factor). Inertia is typically good, higher speeds are good, and high wing loadings are good. Long story, but it's how the airplane penetrates the gust (and how the angle of attack is changed). 2b) Well ,,, and this is where I'm going to get misquoted . Yes, Va is determined by Vs and load factor at gross weight, but … the wing is typically NOT the limiting factor. I'm going to make up easy numbers. With a GW of 3.500 lbs. (minus 500 lbs. of wing), the wing has to lift 3,000 lbs. per G. At a max G of 4, the total wing load is 12,000 lbs. Now if we lower the weight by 1,000 lbs, the wing at 4G only has to lift 8,000 lbs, so the wing is fine. In fact in the lower weight case, the wing could take 6G to get to the 12,000 lbs. BUT, and here comes the kicker, the engine and propeller (at 600 lbs.) weighs 2,400 lbs at 4G … which the mounts are designed for. But at the lower weight and 6G (same wing load), the engine weighs 3,600 lbs and breaks the engine mounts. This is true for all fixed weights, including pilot, passengers, baggage, etc. In the lighter weigh case, the wings won't break, something else will first. 2c) Maneuver speeds are just a function of Vs and Gmax. You would have to have a really, really light airplane that has a very high gross weight … I'm not sure if the airliners even have that good of an empty to gross weight ratio.
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1) Again, thanks, @cliffy. I learned something new again today. It's a good day. 2) I like the way you're thinking . Most aircraft engines are aft end mounted, making the engine mount itself the lightest it can be. Yes, there are some that are bed mounted (like the Bonanza), but this is because the landing gear structure is already there. We try to put as many/much loadings into one piece as possible. This way less parts have to be heavily loaded and heavy (weight-wise) … especially if those loads happen at different times. High wing taildraggers are a great example. Wing lift loads (the strut) comes into the fuselage at the same place that the gear loads come into the fuselage. Both loads are very high, but they don't occur at the same time. As for hard mounting the gearbox, that is a thought … and a tradeoff. Now all the propeller gyroscopic loads would need to be carried by the gearbox mounting structure, which is (roughly) 50" ahead of the firewall. Remembering that most tubing failure modes are in buckling, the tube lengths are going from 14" to 50". This is something that would have to be looked at on a case by case basis … especially if the engine is bed mounted and the nose gear structure is not mounted to the firewall, too (again, Bonanza style). Great thought!
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Thanks, @cliffy ! 1) All certificated airplanes must perform incipient spins (longer of 1-turn or 3 seconds) and recover in 1 additional turn or less in all configurations. All airplanes approved for spins must perform 6-turn spins (established) in all configurations and recover in 1 1/2 additional turn or less. The spin program adds ~$2M to certification … if all goes well. So fixes are quick and easy and others have been up to a year. 2) I agree with you that this thread is wonderful. All y'all have been awesome! It's not over yet
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Thanks @carusoam! So ,,, the EPI guys wanted an apples to apples comparison, but … they themselves didn't do that. The original Shrike engines output 375HP where the Orenda engine outputs 500HP (both geared for more torque). Which means the twin originally with 750HP was going to be certified with 1000HP, a 33% (250HP) increase! They mentioned that Vmc was not changed, but I have my doubts about that statement. The EPI table presented on their website @carusoam quoted above doesn't tell the whole story without a little math (or an added line item). Numbers can be made to say what you want. All the certificated, air-cooled engines in the EPI table have a weight/HP ratio of ~2.25-2.3 lbs./HP. The certificated, liquid-cooled, Orenda engine is only ~1.83 lbs./HP, which is a huge weight savings … if you want/can handle substantially more HP. Apples to apples the Orenda wins. In addition, adding weight to the wing lowers the wing bending moment and shear loading to the fuselage. Landing loads are another story, but they are typically not limiting. To ease all our MooneySpace minds, the M20s (and the vast majority of small, GA airplanes) have a maximum zero fuel weight equal to the maximum gross weight of the airplane. IOW, the entire gross weight of the airplane (minus the weight of the wing(s)) can be taken by the wing and fuselage. Wing bending moment is decreased by fuel weight. Confusing, but if that doesn't make sense I can explain more if someone asks.
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Interesting, but Why? 400HP on a C172? It's a homesick angel with 225HP O-470 (yes, there's an STC for that). Just a side note, but is the company name an oxymoron of "Quiet Aviation"? A 300HP C180/185 propeller goes supersonic. He'll need to go to an 8-bladed prop to absorb all that HP.
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@Raptor05121 Is this in Florida? I plan to attend Sun-N-Fun. It would be a great side trip! Thanks!
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@John Mininger I have also heard a rumor that NASA bought a lot of LS-series engines to use as gensets (generator sets to produce electric power). Not sure for which research airplane(s). X-57? Now that I think about this more and knowing electric airplanes are already weight challenged (and a genset is not weight efficient), they're also going to need to add the Flight Engineer station back into the cockpit so they can tell where all that smoke got out of the plastic tubing so that they can try to stop that from continuing. Skywriting in an electric airplane just isn't real cool … yet.
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@McMooney Have you really installed an hour meter in your car? … and is it straight time or tach time? Not only am I laughing now, you are my hero if you actually have an hour meter in your car. PS. Trying to use previous data and data from other industries to cut development costs.
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@Mooneymite Cool! They get more then automotive-rated HP and longer life out of a stock engine than the OEM!
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That my story … and I'm sticking to it. I could write a book. Oh wait, there's more to that, too. The funniest (depending on one's viewpoint) part about my entire career has been that I am often brutally open and honest (and always honest), and people don't believe me. But they will turn around and believe anything that can't physically be possible. I know that I am not alone, but there are fewer and fewer of us daily.
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@Stephen I honestly think that the M20 could pass spin testing (if not with minor mod), but the real question is, "Why?" There is good vertical surface area outside the horizontal wake. On most models there is rudder below the horizontal (better if it were trapped by the horizontal). The nose goes very low on entry, but … The loss of altitude is very large. Spin recoverable only gains the ability to practice loss of control at higher altitudes … not so much in the pattern. Definitely don't try this at home (or airborne) … especially without a spin chute.
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@steingar Agree with you, and Ron W. does a great job of both acquisition of the accident data and the analysis of it. On a good note for the rest of us, time is not money for most homebuilders. Most will spend hundreds of hours to save a couple hundred dollars; I applaud their efforts (I too am one). I talked to a former co-worker and friend about some of his projects a couple days ago. One was converting a marine engine for aircraft use (for an outside company). I kinda questioned his logic on cooling. Marine engines are very compact, and an infinite water supply is critical. He said that they hadn't looked into cooling real well yet. We'll see. The LS/LT-series was built for high power. My plan is not to go there Similarly, O-200s that output 200+HP don't do it for very long either Thanks, Ron PS. Had to look up KOSU to see which school won that battle. Go Big Ten!
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Okay. You win, @Yetti If I think it is difficult to cool a water cooled engine, you'll have a great time trying to lower the drag of air cooling 9, individual cylinders evenly around each cylinder. I am kinda curious how a Mooney would look with a radial on it (I know someone will photoshop it). The Mooney does look good as a taildragger, though. Y'all are awesome!
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I have a source for data of these engines running for 2.5-3 years at full power, stopping for oil changes only. If the source comes through, this data "may" be the tipping point. Keep the information, questions and doubts coming, I LOVE data! And live in reality.
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@John Mininger Thanks for the article. I have found a lot of the PAV data. Their goal was a little different, but it is very applicable. They wanted to use the engine "as is" without a gearbox, which causes great inefficiencies in the application. @Andy95W You're definitely not a buzz kill . Reality is reality … I get into trouble for stating the truth, too . Now to address your greatly appreciated comments. The big difference between aircraft engines and automobile engines is the power output and schedule. A car uses high horsepower for a very short time and low horsepower for a long time. It also goes up and down in power a lot. An airplane engine on the other hand is at high power ALL the time, but it doesn't go up and down in power a lot. And most importantly doesn't need low-end torque. Personally, I laugh when people mention that electric motors have great low-end torque, and the torque curves are almost constant. Torque required is determined by the propeller. More RPM; more torque required. More blade angle; more torque required. RPM is set by propeller diameter (or vise versa). Aircraft engines run at a constant RPM … almost 100% of the time. More directly, the Orenda engine doesn't exist today because one can't take a car engine rated at 200 HP in a car and run it at 200 HP continuously in an airplane. It runs at 25-30 HP in the car.
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Wow! I just gotta say that all y'all are good. I'll a couple comments. 1) Although there is a single set of regulations, ACOs do interpret them differently (or at least used to). In addition, the thoroughness of an STC is typically less than the TC holder (OEM, Mooney in this case) would look into. In addition, the OEM will also know all the critical areas to look at. In this particular case as @Oldguy so beautifully pointed out, the wall thickness of the fuselage tubing changed. This is a modification for a compressive failure (buckling). Engine loads will definitely travel through those tubes. 2) It is hard to look at everything without knowing the weakest point(s). In a Mooney, the wing typically isn't the weakest point. Landing gear, maybe, but not always. If the Js have the same gear as the long-bodies, then the gear is not the issue either. The OEM will follow the entire load path, where an STC applicant may not. 3) If one has an accident and the aircraft is over the certificated gross weight (i.e. considered unairworthy), it is highly like one will be footing their own bills. 4) On a related note, everyone thinks that Va is an airspeed for keeping the wing attached, but that is only at GWmax. The wing is fine at lower weights to go to higher G-loads (same total lift). What is NOT covered is going to higher G-loads on the engine/engine mounts, baggage areas/floor, occupants going through the floor, etc. 5) On most typical small GA airplanes there is no GWzero fuel (zero fuel gross weight). IOW, the wing is designed to take the entire maximum gross weight (minus the weight of the structural wing). Rarely do we fly with no fuel in the tanks (fuel relieves wing bending moment … but is required for powered flight). Keep the Blue on Top, -Ron
