Jump to content

rahill

Basic Member
  • Posts

    65
  • Joined

  • Last visited

Profile Information

  • Gender
    Male
  • Location
    Reid Hillview Airport, San Jose, CA (KRHV)
  • Reg #
    N201CD
  • Model
    M20J

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

rahill's Achievements

Enthusiast

Enthusiast (6/14)

  • Reacting Well
  • Dedicated
  • First Post
  • Collaborator
  • Conversation Starter

Recent Badges

29

Reputation

  1. It didn't stop Santa Clara County - they banned the sale of 100LL more than a year ago with no viable alternative available. That was done to speed up the closure of the airport, not to sell unleaded fuel.
  2. I appreciate the effort you put into developing the fuel. Unleaded auto gas has been around for almost 50 years (1975), it's amazing that 100LL has lasted this long. It's extremely fortunate that as more local communities grab hold of the lead issue, significant or not, there's a viable alternative on the horizon.
  3. And if you saved your earlier cradle (they're cheap, about $18 each), the iPad mini 6 fits in the cradle from the iPad mini 1.
  4. The real reason they did the lead study is to prove the airport is unsafe and therefore close it. It's just the latest approach, and it seems to be working. It has nothing to do with encouraging pilots to move, they're not trying to prove the airport is underutilized (it's not!), they just want it gone. The fact that there's now an alternative to 100LL for the majority of the aircraft (and by Q2 2022, all aircraft), especially the training aircraft which make up a huge percentage of the use, didn't really occur as an option to the anti-airport crowd when they glommed onto the lead issue - and it probably doesn't matter. Hopefully transitioning as many aircraft as possible to UL94 (same cost as 100LL) now may ease some of the "close it now" calls.
  5. I think it has to do with compression ratios, although that may be a bit simplistic. Even some of the lower horsepower IO-540s are able to use UL94 and it turns out they have slightly lower compression ratios too. Sent from my iPhone using Tapatalk
  6. The flight schools at RHV have largely switched to UL94 fuel, and had so before this latest announcement in an attempt to be a proactive solution to the problem. That works for a lot of people, including many (all?) of the carbureted Mooneys, but it's not available for fuel injected Mooneys.
  7. This is super annoying, but to blast it as a California problem is short sighted. Reid Hillview, along with other urban airports nation-wide, have been threatened by development and other issues for decades. The lead issue is the latest weapon in the arsenal against the airports, and frankly it's a little surprising it's taken this long. Leaded auto fuels were phased out in the US 45 years ago. Read the lead report that Santa Clara County commissioned. You could see the conclusion before it was even presented, but there are countless arguments about the effects of what were thought to be trivial lead levels being an issue. Was it biased and predetermined - yes, it seems so - but the counter arguments seem cold-hearted, poorly thought out, and aren't helping much. What would be needed is a comparable report proving that the lead from 100LL is not an issue. Removing 100LL from the airport is no-doubt going to cause major inconveniences and possibly safety hazards, but it's the county's immediate response to the issue. Don't dismiss this as a "liberal CA thing", it's been simmering for a long time.
  8. http://static.garmin.com/pumac/sa01899wi_aml.pdf
  9. Understood, she already told me that "xfoil doesn’t account for vortices, wing-body join, interface between the two airfoils, etc. so there are probably a lot of things contributing to the differences". I think she gets it.
  10. I've already got my daughter plugging numbers into XFOIL and wondering why the airfoil numbers don't match the measured data. I think we may have you beat in the geek department. Rich
  11. Oh, if you can find the drag polars, please share them - those would be cool to see. Rich
  12. But that reference states "This approach only holds for a blunt impactor (no aerodynamical shape) and a target material with no fibres (no cohesion), at least not at the impactor's speed. This is usually true if the impactor's speed is much higher than the speed of sound within the target material. At such high velocities, most materials start to behave like a fluid." (note: speed of sound in aluminum is ~6000m/s) It then goes on to discuss very high density projectiles, shaped charges, and the like. That's not the case here. Perhaps you meant to include the reference about impacts (from the same site) https://www.revolvy.com/page/Impact-(mechanics). "When vehicles collide, the damage is proportionate to the relative velocity of the vehicles, the damage increasing as the square of the velocity since it is the impact kinetic energy (1/2 mv2) which is the variable of importance."
  13. This was covered in the video (the longer one, not the 0:43 second clip). An equivalent mass bird deformed more and did less damage. The density of the drone, particularly the heavy battery, is something to consider.
  14. Energy goes up as the square of the speed. They address this in the video and mention closing speeds, assuming some velocity of the drone. The DJI they used is capable of 30+ mph so take that into account. 238 mph is maybe a bit fast, but (also addressed in the video) these things have the capability of doing more damage than an equivalent-mass bird.
  15. Can you double check this, or provide a reference? Best glide in an M20J is about 90 kts (load dependent). The low point in power curve (left of which is "backside") is the point of minimum drag, not the point of best glide. Best glide (L/Dmax) is to the right of that. I know we're mixing up topics now, but if you cross the threshold of Palo Alto at 80-85 KIAS, you're probably not going to land on that attempt. Rich
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.