jaylw314

We're talking constant airspeeds here. When you start your climb or descent, RPM and power are unchanged until airspeed changes. That's a whole other variable.

Because the power is not (just) being used to overcome the drag of the blades, it's being used to perform work on pushing the air. I recall reading GA props can be up to 90% efficient in terms of motor power being turned into useful work. So while that remaining 10% is presumably used to overcome drag (and that presumably goes up to the cube of RPM), the other 90% simply reflects the amount of power the motor is putting into moving air. I suspect if you crunch such numbers, the final power output will be proportional to RPM, minus a few percentage points as it increases.

That was kind of a point of the Carson's speed discussion, that if Carson's speed is the minimum of specific power vs speed, then around Carson's speed the power per speed will be pretty linear. Up around 200 knots, maybe not so much

Thanks, I hadn't realized that nuance about KERS. I guess the only fundamental differences with the WRC Rally1 car is that the driver has no override AFAIK, and the electric motor peak power almost doubles the total peak power of the car!

I just remember my days in a Cherokee 140, where the power with a fixed pitch prop is directly to RPM, but that's an even worse comparison to a P-38!

It's 45 degrees because the graph is normalized to make the line 45 degrees for visual clarity. You could rescale the axes to make it any angle you want, the slope (in the GvK diagram in the article) is still 0.00018 in the units they used.

I see what you're saying, and I'd agree that cost is an important decision-making factor for people, but I think developing a psychological model of decision-making was far beyond the scope of what the article intended. Arguing that since it fails to do so, therefore it's conceptual conclusions are arbitrary is a bit of a straw man argument. The scope of the article seemed to be limited to "This is why you should value specific power, and if you value maximizing specific power, this is how fast you should fly."

I guess my nitpick with KERS is that if the default is to allow the driver to control it, it's NOT for curbing emissions, because that's the last thing on a racing driver's mind

True that. I'm just guessing that the RPM stuff is based more in the laws of physics than engineering, but that's not always accurate My thinking is that if they turned off the governor, the power output is directly proportional to RPM

Yeeeeesss, that's sort of true, although AFAIK the goal of KERS is performance, with a button for the driver to use the extra power for a brief boost. That doesn't strike me as significant in terms of curbing emissions. In my book a hybrid system has to be on by default. Of course, WRC is unique in that each special stage is only 15-20 minutes of hard driving, so the teams have to develop an energy management strategy by adjusting how much is used on accelerations, so that you start with a full battery, and end the stage just as the battery is running out. It's not clear to me if they can change this mapping once per race, on any repair stop, or before every special stage. There are also the long stages between SS's driving on normal roads where the battery can be recharged while driving. From an interview: “So the driver is not allowed to have, for example, a separate switch to add boost or some indication of how the boost might come, it has to be integrated into the torque path so that you have a combination of internal combustion engine and electric motor combined into one torque which is linearized through the pedal map. “And that’s the way it has to be deployed, so effectively if you have the boost available then you have a combination of engine and motor together and if you don’t then you have only the engine.”

FWIW, I suspect if the P-38's were only dropping 50 RPM, they were probably still ROP, since that's about a, what 3% power drop from 2000 RPM? LOP would probably be more than a 5% drop. I've flown LOP enough I can tell when I'm in the right ballpark by the change in the engine sound while pulling the mixture, although that's obviously not terribly accurate... IIRC, the ff to power ratio LOP in IO-360's is about 15.1, so 65% amounts to 8.6 gph, and 70% is 9.2 gph. I just shoot for a FF of 9.0 gph in cruise call it a day. If I'm below about 9,000' MSL, I'm LOP, if I'm above, I'm ROP. Also FWIW, I hadn't realized the WRC has changed to a hybrid-gas standard platform this season, AFAIK they're the first top-tier racing circuit that has.

That's sort of true, but impractical. There's a point richer than best power that will produce the same power as a mixture LEANER than best power. In practice, there's not an easy way to figure where those points are. I don't think any of us actually run anything richer than best power other than full rich) during normal operations.

I think the point of his mentioning the GvK line is that their work suggested a line of some slope in that graph of P/WV vs V (not 45 deg, where did you get that from?) that may be a theoretical limit. His calculation of a Carson's speed approximates what the slope of that line should be. IOTW, I think you have it backwards. The slope of the line does not suggest Carson's speed, it's Carson's speed that suggests the slope of the line. FWIW, the cost of fuel affects this calculation not at all.

?? I just use the blade in my multi-tool. Any pocket knife should be long enough to cut through

Don't know the answer, but Challenger owns the STC and produces aviation air filters using K&N filters Edit: From Aircraft Spruce, look for Challenger Air Filters--

Volume air flow is always proportional to MAP x RPM, right? Mass air flow you can get by multiplying by air density, which itself just needs a fudge factor for inlet air temp. Whether any motor is turbo or NA, or low or high compression shouldn't matter any. I assume there's also a fudge factor for volumetric efficiency, but AFAIK that's a relatively small factor for our low RPM motors(?) But at least in theory, you could calculate your % power by taking (MAP / MAP at max power) x (RPM / RPM at max power) / max power (x100%) if you're ROP. In my M20J POH, that gives you a number about 4-5% above the listed % power in the cruise power schedule.

Notwithstanding your exquisite proficiency and excellent physical shape, when did brakes become common on the right side in Mooney's?

I'd probably go directly to any sizeable airport with an instrument approach if I can, and make about a 1 nm radius circling above the airport at minimum descent rate until I broke out. Not great, there's no guarantee of being lined up for anything, but if there's a circling approach you figure there's protected area of about 2nm radius. My chances of breaking out with clear space in front of me is a lot higher than any other strategy I can think of, other than moving to Kansas...

Some nuances I didn't see addressed: The commenter claiming to be the pilot did not explicitly indicate if the passenger seat was empty. He did mention a wife, and having a non-pilot wife in the passenger seat with the only remaining controls could certainly make the switchover extra complicated, no? While moving from one front seat to another is doable, it is definitely MORE difficult than some other aircraft. The center pedestal is quite prominent, and your legs go way past it compared to, say Cherokees and Skyhawks. Ironically, if you're short, I think it's more difficult, since more of your body is forward of the center pedestal, so you'd have to slide the seat all the way back. Throw in a front seat passenger and it's impossible unless you've both practiced ahead of time. I still have my Telex microphone sitting in its holder, but it's unplugged. I should probably check to see if it still works. I assume the pilot was temporarily nordo because the PTT wire broke when the yoke came off. What fraction of Mooney's don't have brakes on the right side? Mine does and I've always taken that for granted...

The nosewheel steering is much less sensitive if you hold the nosewheel off the ground after touchdown Just remember during crosswinds landings to center the pedals quickly when the nosewheel actually touches down.

You know that phrase "like there's no tomorrow", as in fly like there's no tomorrow? That's a bunch of BS, it just makes you afraid of losing what you have. Instead, you need to fly like there's ONLY today, so you don't have any regrets whatever tomorrow brings. I mean, heck, we get to fly these amazing machines, how many people get to say that?? On the other hand, Yoda probably was more eloquent "Fear is the path to the Dark Side. Fear leads to anger, anger leads to hate, hate leads to suffering"

I suspect that the majority of Americans are disinterested, apathetic or against supporting our right and privileges to fly Mooney's. I suspect we're seen as prima donnas and JFK Jr wannabes, and that most Americans believe they receive no direct benefit from having an airport in their locality. I suspect we're seen as manifestations of the 1%'ers, because most of us, in fact, are, to be able to afford to own and operate aircraft. If put to a truly democratic vote or referendum, our privileges would have been voted out decades ago. If government were simply, as you put it, the "servant of the people," we wouldn't be here in the first place talking about Mooney's. MS would have ended up being a forum of some other financially ruinous activity Somehow, that government and those regulators have got it in their heads that GA should be supported rather than shut down despite popular opinion. I, for one, am thankful for that, even if there are pockets of antipathy towards GA.

Click on the "ATC Notices" on your Leidos website dashboard:

Thanks for clarifying! Although in fairness, saying they are not toxic is not accurate, since everything (almost) is toxic at a certain level. It's like that old saying, "the dose makes the poison", not the label. As it turns out, there have been plenty of examples of deaths from toluene and xylene toxicity, but they're pretty unrealistic for most people. That is what's different about lead--unlike most chemicals, some type of toxicity has been found at typical environmental exposure levels Also, claiming they are not carcinogens is about as inaccurate as claiming they are carcinogens. Like 99% of chemicals out there, there's insufficient information, although the I'd agree it's probably more likely they aren't.

Washing my hands with benzene in organic chemistry lab notwithstanding, there is overwhelming evidence that no level of lead is safe. That being said, don't wash your hands with benzene