mooniac15u

I'm not trying to suggest that the current rules make sense, just that it's not actually legal under the current rules for a pilot to replace these bulbs. Perhaps we could convince EAA/AOPA to put some pressure on the FAA to revise/expand the preventive maintenance list.

If your gear down light burns out it has an impact on safety of flight which could reasonably be considered an emergency. During an emergency a pilot is authorized to deviate from the regs to the extent necessary to deal with the emergency.

I recognized the indicator light from the picture. I owned an M20D before my current M20J and it had those indicator lights. The simplicity of a task does not seem to have any bearing on whether the FAA thinks a pilot should be allowed to do it. For example, changing spark plugs is far more complex (and potentially riskier) than unscrewing a light bulb. But, as far as I can tell, spark plugs are on the list and interior bulbs are not.

Replacing bulbs like that seems trivial but is there an actual legal basis for a pilot to do that work? I know position lights and landing lights are allowed but is the same true for interior bulbs?

Are you talking about the connecting rod AD? http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/e0ce3e112906b48286258178006891ae/$FILE/2017-16-11.pdf

You are definitely getting closer but there are still some problems with your calculations. Let’s start with the battery. Tesla has an 85kWH lithium-ion battery that they use in vehicles today that weighs 1200 lbs. That would power the 85kW motor at full power for an hour so that part of your calculation was very close. There are some new types of battery media that are in development that do better than that but let’s stick with an actual battery pack that exists today. Your calculation is based on driving the motor at full power but you keep citing 6 gph for your C152 which is the fuel burn rate for 75% power. So, for a fair comparison we only need 75% of the battery capacity which is about 900 lbs. You have also failed to account for the different engine weights. The C172 uses a Lycoming O-235 weighing in at about 250 lbs. The engine in the Pipestrel weighs about 30 lbs. Since the 30 lb engine is about the same weight as the 6 gallons of fuel that’s a wash and we can just subtract the 250 lbs from our 900 lb battery weight and we are at 650 lbs differential. There’s probably some other weight to subtract like starter, alternator, vacuum pump but let’s just go with 650 lbs. If the empty weight of a C152 is around 1100 lbs then the “full fuel” weight of the electric “1-hour” version is 1750 lbs and with 2 passengers it’s up to 2150 lbs. which is only about 500 lbs over the current max gross. Since we’re talking about a new composite airframe rather than an actual C152 there should be some weight savings in the airframe. It’s also not clear that you need that much battery because at “idle” the electric motor not only uses no power it actually generates power from the spinning propeller. I’m not sure where your 11,370 lb calculation came from. Based on the Tesla battery it looks like we need at most 900 lbs of battery per hour. An 11,000 lb plane would have about 10 hours of endurance. I think that’s more than your C152. If we assume 4 hours endurance is needed that takes us from 2150 lbs to 4850 lbs. That’s less than half your estimate and less than a quarter of your first 20,000 lb estimate. I don’t think a 4850 lb aircraft is practical but let’s stay away from hyperbole in the estimates. Also, the stated mission was not a full C152 replacement. It was a trainer that did short hops in the vicinity of the airport.

Your math is faulty. The fuel contains that much energy but piston engines are only about 15% efficient in converting that energy to motion. Electric motors are closer to 80% efficient. http://www.pipistrel.si/news/wattsup-the-new-2seat-electric-trainer-took-its-maiden-fligh

I guess you should tell these guys that they are wasting their time: http://money.cnn.com/2017/11/28/technology/electric-plane-siemens-airbus-rolls-royce/index.html https://www.reuters.com/article/us-aerospace-hybrid/boeing-backed-hybrid-electric-commuter-plane-to-hit-market-in-2022-idUSKBN1CA16A

Energy density is an interesting factor but it's not actually relevant until it becomes a constraint. If the batteries provide enough range/endurance and allow for enough useful load for the mission it doesn't matter whether you could have accomplished the same with less total mass of fuel. For example, a primary trainer that carries a student and CFI and never travels more than 20 miles from the airport. I spent many hours training in a Cessna 172 that carried around about 200 extra pounds of fuel and several hundred pounds of unused useful load that I was never going to need during training. A battery powered electric trainer would have been fine. For longer range applications hybrid-electric fills the gap. Running a liquid-fueled generator to power the electric motor allows both the internal combustion engine and the electric motor to always operate at peak efficiency. DIesel/electric locomotives have been demonstrating this principle for decades. The problem most people have in comparing energy technologies is that they tend to dismiss alternative technologies that are not a complete 1:1 replacement for fossil fuels. The long term solutions will vary by application.

It appears that internal combustion engines are nearing the end of their run as the dominant form of propulsion. Electric and hybrid-electric is the future. We are already seeing it in aviation. Even Boeing is working on electric engine technology.

The experts in a field are the last to see disruptions coming but they will be loudest voices telling you why it can't happen. Remember when ridesharing wasn't a viable business model because the taxi industry was too heavily regulated?

Don't stop dreaming and don't listen to the naysayers.

MooneySpace is not the place to propose anything optimistic or disruptive unless you want to hear all about how it won't work. It's the industries most ingrained in their ways that are the most ripe for disruption.

I'm not sure why you are pointing this one out to me as one of its key points is that millionaires don't leave areas because of taxes. The problem with opinion pieces in general is that they start with a position and then look for data to support it. This is the opposite of sound scientific research where the conclusions are drawn from all the available data. People writing opinion pieces are prone to cherry picking data to support their position. Another problem is that opinion pieces are not generally subject to the same level of fact checking as regular news items. In terms of the migration data itself a key missing piece is where Californians are migrating to. You can't just look at states with net out migration and others with net in migration and conclude that people are moving from one to the other. The people leaving California may be more or less evenly distributing themselves across the country while the people moving to places like Texas may be coming from equally distributed origins. There just isn't enough data to draw any significant conclusions.

They can make a lot of interesting shapes when producing power. They can bend forward because the blades flex forward towards the tips as they pull the plane.

The data does support that California has a net outbound migration. That is a long way from supporting your claim that: "...many wealthy people who pay the taxes are moving out of California in record numbers." The data doesn't provide wealth demographics and it doesn't provide information on why people are moving. That is pure speculation.

It's hard to tell on the other blade due to the angle of the photo. Either way the tip isn't bent back.

That is also an opinion piece. The data presented is based only on those who use that particular company's services and doesn't provide demographics. They attempt to correlate moves to specific economic factors but that kind of correlation can be spurious particularly when looking at a self-selected population segment. Did you notice that this was the first year California made the top 5 in their list going back to 2011? https://www.northamerican.com/migration-map

The tips bend backwards when the prop is windmilling. The blades typically get a more gradual forward bend when the engine is making power.

It looks like at least one and maybe both prop blades are bent forward. That usually happens when the engine is making power.

You know that's an opinion piece, right?

That's right, it wasn't related to the manual gear. The difference would be that with an electric system none of the gear would've moved and I (presumably) would have known they weren't down. I was really just pointing out that the manual gear can and do fail. I had generally considered them failure-proof up until that point It only broke one rod connected to the right main gear. The other two went up and down easily after the failure. A pilot friend was at the airport and helped me talk through the options over the radio. There was much discussion of the pros and cons of keeping the two gear down vs raising them. If I had two mains I would've used them but the assymetry seemed dangerous so I went with the belly landing.

Mine was definitely an unusual case but there is a known issue with the J-bar.

Maintenance induced failure. One of the mains got wedged in the gear bay and wasn't going to move. You can apparently put a lot of force into the system with the J-bar because one of the pushrods broke when I tried to put the gear down. At that point I had one main and the nose gear down and one main still retracted but no way to know that. A pilot on the ground notified me of my problem and I ultimately retracted the gear and landed on the belly. There are also other failure modes such as cracking at the bottom of the J-bar and the bar not getting fully locked into the block. My incident didn't actually lower my opinion of the manual gear overall. I still like manual gear Mooneys and I know the system is very reliable.

I had a mechanical failure in my manual gear M20D that prevented my gear from coming down. So, I don't think I'm going to develop that bond.