ajudson

It is true that there is net zero momentum accumulation across the entire semi-infinite atmosphere -- eventually all of those particle collisions will impart their momentum into the ground and cancel out to zero. Induced drag in this particle kinetic view is simply the momentum transfer in the perpendicular direction (the wing deflecting the particle downward results in the wing gaining some momentum upward -- lift, and losing some of its forward momentum -- drag). Edit: refreshing myself with McLean's (very good) video, the end touches on this a bit -- look at his pressure integrals for a pancake control volume. In the semi-infinite case (with a ground plane), the particle collisions eventually impart the entirety of the Lift force into the ground. In the upward direction, eventually all of the particle collisions slowly dissipate to a smaller and smaller pressure disturbance, summing to zero at infinity. The net force is still L upward. Although there was zero momentum accumulation in the atmosphere, the forces were still imparted by every particle collision involved.

Think of it from a particle kinetic theory perspective. Pressure is just particle collisions -- and those impart a momentum. This video helps to visualize what is happening at the micro level (with some simplifications). You can derive all of Navier-Stokes from this fundamental approach. The summation of forces from all of these individual collisions results in a lift vector that is a function of airfoil shape, relative speed, and angle of attack. Whether you capture this on the macro level in the form of pressure, streamlines, or any other method, the fundamental process is momentum transfer and equal reactions (via Newton - a net mass flow downward for vertical lift). This is not necessarily "downwash" that you are thinking of on the macro scale, as Hank and MikeOH allude to (to be a little more clear here: as the particles collide and transmit their momentum, there is an effective downward motion of a parcel of air on the macro scale).

I am also looking for a tach generator (0400-004 or 880053-501) if anyone else is looking to sell.

Thanks for the information! I will have to look into it closer when I get back out to the plane.

Had an unexpected surprise last night. Just as I rolled onto the runway and applied full power -- assuming because the alternator was then providing the full 28v -- the center bar mounted compass began to aggressively spark and burn under the swiveling cover (circled in the attached picture). I'm not sure what exactly this cover is for (fuse for the compass light?). I quickly aborted the takeoff and flicked the cover off to stop the burning. Definitely spooked my girlfriend for a little while. The compass is an Airpath. Do I just need a replacement fuse (or whatever is under that cover)? A new compass? Or is there something worse I need to be worried about? Thanks!

I had a similar problem with my '87 J. After troubleshooting with a few different mechanics, a new gear limit switch (didn't help), and nearly 10 hours of labor put into the issue, my A&P finally traced it to a rubbed/burned-through portion of the wires that was shorting during flight. It was also intermittent during flight. It's a tricky one to find, but I'm happy the breaker hasn't popped since! Not sure it was worth the AMUs I put into solving it though....

I have been trying to understand how this works. It seems that any CFII would be fine as long as I am PIC. But I assume during the IFR cross country I would be taking a risk if I am not technically PIC? What about during Simulated/Actual?

I am looking for a CFII who can help me finish out my IR in my J. I am based out of M54. I have talked to a few CFIIs in the area, but have not found one with Mooney experience. My insurance open pilot clause requires at least 25 hours in a M20J. I could probably add a named pilot with a different experience level, but just thought I'd check here first before going through that process! Thanks!

Thank you everyone for the great advice! I talked to Cole Aviation and it sounds like they're going to be able to fit me in.

I am looking for a good maintenance shop for my new-to-me J's first annual next month. I have talked to several shops in the area (Mack Air at SYI, Forge Flightworks at MQY, and Wingnuts at M91), but I am not sure what I should be looking for to choose a good shop. Forge Flightworks (formerly Carpenter Avionics) is apparently a Mooney Service Center, so I am currently leaning towards them. But I have only heard about their avionics work, and nothing about annual inspections there. Has anyone taken their Mooney here? Wingnuts and Mack Air both seem knowledgeable, but they are not Mooney specialists. Not sure if that is important for my first annual with this airplane. It had an annual completed by Don Maxwell a few years ago, if that matters. It also has previously had an annual performed by Mack Air. Does anyone have any recommendations in my area? Am I thinking too hard about this?