AH-1 Cobra Pilot

Well, at 40 mph, the acceleration on the rim of a 27" diameter disk will be over 3000 ft/s2, and at 20 mph it will be 1/4 of that, so without figuring the mass of the tire tread in contact with the road, I would still call that a significant difference.

The planform area also matters.

Sure, tire rigidity, for one.

Concerning #1 above, is there a difference? (Ignorant vs. stupid, maybe.) I equate the whole electrification vs. ICE to bad religion and these people are simply true believers. I just got back from Oshkosh where I ran across a few of these cultists. For anyone who can do the Math, the claims by these people are hilarious. For instance, taking the range claim of one Ecraft would have to be done from take-off to landing at 23% power! Do you know of anyone who recommends less than 100% take-off power, especially in something with only about 80hp? I do not know if they are intentionally lying, but they sure do freely spew BS from their mouths. Note that Tecnam just quit trying converting their fixed-wing aircraft to electric power, https://www.greencarcongress.com/2023/06/20230617-tecnam.html , yet Joby has received almost $1B in funding. When might that idea pay off? 40 years, once battery technology catches up? And do not forget Terrafugia. As I recall, in about 2006, they promised a flying car roadable airplane in three years for $125,000. A few years later, it was due in four more years at $250,000, and a few years later was due in five years for $375,000. Now they are Chinese-owned and continue on, yet, with no production... Airplanes are difficult in so many ways. Most of the tough problems were solved decades ago, and we are, fortunately, still profiting from those investments. The potentials gains we should be focusing on right now are relief from regulatory burden from the FAA. (Why are avionics for Experimental Aircraft so much cheaper?) As a side note, I have an idea for fuel injectors that should provide better fuel atomization, thus better power and efficiency, but the FAA requirements to even test them makes the idea unprofitable, thus moot.

I finally have ETA covers that I am willing to sell. They are a bigger PITA than the Klixons, due to being less robust; i.e. the internal 'bridges' are more susceptible to breaking when removing support material, the sides and faces are thinner, laser etching is more difficult, etc., but they work. PM me if you are interested.

Just don't stick your hand out!

The ETAs are much more difficult than the Klixons. I am still working on them.

The best bet would be to find one, then take it to someone who has a scanner. Then it would be easy to print, but would still require some iteration to get exactly right. It is also a little known fact that most 3-D prints are not water tight, and one built this way might leak.

PM me. I have a good supply.

This is the back-side of a Klixon switch cover.

If an airport charges landing fees, it should have to make a sign saying so that is visible to anyone landing there from a distance of, say about 3 miles, and publish that fact in all FLIP.

I would like to see more emphasis on pressurization, but... What does that add to the price? Does anyone have an approximate idea of the original price difference between Piper's Malibu/Matrix, or the Cessna T-210 vs. P-210, etc.?

IF that is incorrect, you prove it. Graph y=x2 for x=1 - 10, which is a similar curve in the chart Carson uses. Tell me where the optimum point is. He does it by using his "Limit Line", (or in other words, adds another equation), which comes from a paper by other authors that may or may not be relevant, then justifies his choice thus, "Their work showed that there is an apparent technology barrier (which they cautiously referred to as "almost a kind of universal law")..." If that is not hand-waving, I do not know what could be.

I see this: "This quantity has a minimum, i.e., ... when a* = 31/4, but I do not see the other. What is the maximum of value of dP/dV? On the next page: "This result is remarkable on two counts: first, it indicates that the common practice of operating piston aircraft at airspeeds about 30% higher than the optimum has a rational basis, although the practice itself has probably evolved empirically." On previous posts, it is noted that this is absolutely not true for Mooneys. That kind of destroys his whole thesis, does it not? When you have fewer equations for your number of variables, your answer is a curve. The only way to get a point-solution is to add another equation to the solution. One way to do that is to insert your own determination of the cost of your time. i.e. If you take fuel at $5/gallon and your time at $100/hour, I guarantee you will be able to determine the exact airspeed to fly. Ahh, but, you say, my time is worth $110/hour! So, some might even consider that solution arbitrary.

Okay, maybe I missed something. What is the slope of that line?

Absolutely not! What you are describing is a curve, not a point/speed. Carson chose a point on that curve at which a line was tangent, but the slope of that line is utterly arbitrary. (In his paper, he does what is commonly referred to a "hand-waving" to justify the slope.) As I have said before, you need one more equation, because you have one too many variables to come up with an optimal 'speed'.

I preceded you by several months in an earlier thread. For this to be solvable, you still need one more equation, since you input one more variable. The bottom line, (as I said earlier), is really, How much will you pay for saved time at the end of your flight? That will tell you how fast to fly.

The switch covers are great. I will have some ready soon.

If you want the vent covers, I will try making you four of them and let you know when they’re done. You will have to paint them with an acetone-based spray paint, as that makes them stronger. They are a direct replacement for the old ones. If you want the eyeball mounts made from PETG, I can probably make them in the next week or two. (I will have to greatly modify the design to make them from ABS.) Depending on the color you want, you might have to become my painting expert, since I have not done much painting of PETG. I can also make them from glass or carbon fiber infused PETG, which will make them stiffer and stronger, but the plastic filament costs 2-3 times as much, and limits the color choices.

Look at the back. This is a Klixon. ETAs have what looks like four pillars with bridges across the tops.

Probably about what the defense lawyers would cost.

Yes. I have been working on two different approaches: A direct replacement of the vent cover, and something to hold an 'eyeball' vent. I have a really good substitute for the cover, although it is best if you paint them, and you have the PITA of removing the rest of the overhead plastic to get them in place. They are tough to print because of the geometry of the part, which makes them prone to delamination and cracking in the printing process. Once treated, they are pretty stable. Painting adds strength, as well. This is the less expensive option, as the eyeball vents alone costs 2-3 times what these will. The eyeball mounts are much worse, as far as delamination and cracking goes. The shape makes them really hard to print well in ABS. I have made some in nylon, but that is hard to paint and much more expensive. I can also make them in carbon-fiber infused PETG, which should be very stable and easier to print, but not as receptive to paint. The great thing about them is they can be very easily installed. (Well, at least you do not have to remove/replace anything else. It is still a PITA to get the hardware in there, up there!) I installed one in my Mooney and am still evaluating it. Please let me know here if you are interested in either.

Yes. I got an STL file that I can print from another MSer. I have no way to test the fit and, because of this, cannot modify the file, so I trust the design is good. I have successfully printed some and will be painting and laser etching them soon. Let me know what letterings you would like. I will start with the standard: NAV LITE LDG LITE STROBE LITE ELEV TRIM BOOST PUMP PITOT HEAT AV MASTER What else?

I just sold my last LOW BOOST, but I will be making more in the next month or so. I will PM you when they are ready.

In 2019 7,921 million Mt of coal were mined in the world. Burning all that would make 32 109 tons of CO2 alone. Add burning petroleum, wood, etc. and you probably get well above 60B tons/year.