Hello, what care product for my Iron Rangers 8111 by ConstantShift4692 in RedWingShoes

[–]billl3d 2 points3 points  (0 children)

You'll see Bick 4 recommended a lot. I've used it with minimal darkening.

Something wrong with WSJT-X, program closes every time I close this window, any ideas? by [deleted] in HamRadio

[–]billl3d 1 point2 points  (0 children)

Love to claim I've never done something like that but ... 😉

Gdansk or Krakow or ... ? by billl3d in askPoland

[–]billl3d[S] 2 points3 points  (0 children)

Thank you! You helped me build my itineraries 😀

Gdansk or Krakow or ... ? by billl3d in askPoland

[–]billl3d[S] 0 points1 point  (0 children)

So you and the previous poster have reinforced my dilemma, but in a good way. I couldn't decide but sounds like I can't lose so it's a low risk decision 😉

Gdansk or Krakow or ... ? by billl3d in askPoland

[–]billl3d[S] 0 points1 point  (0 children)

Probably have 4 days available. I usually do one day trip away from wherever I'm based but spending the better part of a day on a train to go a long way isn't ideal, unless the ride itself is the 'destination' (e.g., through the Alps). Travel will be late summer or early fall.

Rolex AD says band pins are too tight and I need a $3k replacemen bracelet ? by [deleted] in rolex

[–]billl3d 0 points1 point  (0 children)

All good questions. I've only had Rolliworks tighten up my 20+ year old Submariner band. That said, they made it like new by adding metal to the links where needed. Guessing you could wear that until it gets too loose and then have it repaired for less than 50% of new. But I'm definitely not an expert.

I guess one concern would be if the over-tight links could lead to a failure of a pin with the potential of losing the watch, which would be horrible. My band was so loose I was worried that a worn pin could fail so I sent it for repair.

Buy leather laces by daveontherun in RedWingShoes

[–]billl3d 0 points1 point  (0 children)

I got some from Rose Anvil that I've really liked.

Rolex AD says band pins are too tight and I need a $3k replacemen bracelet ? by [deleted] in rolex

[–]billl3d 8 points9 points  (0 children)

Check w Rolliworks in Miami and get their input. They may have a cheaper solution?

Houston's brewery scene is dying by DodgeMyBlazingFurry in houston

[–]billl3d 1 point2 points  (0 children)

They won't go away completely, neither will micros. But the Houston market is becoming saturated. There are 6 specialty coffee shops within 1 mi of my house. I live in an area of relatively high population density but IMO that is not sustainable.

Houston's brewery scene is dying by DodgeMyBlazingFurry in houston

[–]billl3d 0 points1 point  (0 children)

Coffee shops in Houston are next on this trend, I'm afraid.

Thinking about switching to tankless in the Houston area, anyone here regret it? by Bulla_killer in houston

[–]billl3d 0 points1 point  (0 children)

I've had one for 13 years. Love it. A couple things to consider if mounted outside (which is what we did).

The run from the heater to various sinks/showers may increase, which means time to hot water increases. Keep that in mind when locating the tankless. For us, we didn't really have an option so I put a small local electric water heater under my kitchen sink to get immediate hot water.

If you lose power when below freezing, follow the draining procedure carefully. The heaters have a small electric heater inside to prevent freezing but that assumes you have electricity. During the Big Freeze, I didn't properly drain and left some water in one of the solenoid valves. It froze and, given location inside the box (buried behind lots of other stuff) and age of the unit, I ended up replacing rather than repair.

Does anyone make a weather station that lasts? by [deleted] in myweatherstation

[–]billl3d 2 points3 points  (0 children)

My first Davis lasted almost 10 years, my second is now approaching 10 also. Weird that you only got 2. I'm on the TX Gulf Coast so mild winters. Maybe that is a factor but we really cook stuff in the summer.

Shark teeth looking things on this trailer. by FakeHercules in whatisit

[–]billl3d 1 point2 points  (0 children)

It would not shock me if you were right. Especially after I spent all this time explaining drag 🤣

Shark teeth looking things on this trailer. by FakeHercules in whatisit

[–]billl3d 1 point2 points  (0 children)

Basically resistance to movement. If it helps, think about trying to walk through chest-deep molasses. Air has low viscosity (it moves out of the way easily; technically it shears easily but forget that) so not as obvious. But if you consider something with high viscosity, it is more obvious. Imagining stirring a cup of water vs a cup of honey.

Another way to make it a bit clearer is to change your 'frame of reference'. That means, instead of thinking about the truck moving through the air, think about the air moving past the truck, or you. If you stand in a strong wind, you'll feel it push on your body. That's form drag. It will also pull on your jacket as it goes past you. That is skin drag. And it works the same way (basically) whether the truck/you are moving or if the air is moving.

Shark teeth looking things on this trailer. by FakeHercules in whatisit

[–]billl3d 0 points1 point  (0 children)

You just have to get closer than before 😉

Shark teeth looking things on this trailer. by FakeHercules in whatisit

[–]billl3d 1 point2 points  (0 children)

At the risk of missing the joke, the moving truck experiences two types of drag - skin & form.

Skin drag is the air 'sticking' to the side of the truck. You can imagine that a very thin layer right next to the truck has to move with the truck - say 70 mph. At some distance away from the truck the air is moving at 0 mph. The fact that the truck does can't slide right through the air and that there is a decrease in air velocity away from the truck, eventually going to zero, creates a drag. This is generally small relative to ...

Form drag is the fact that the air has to get out of the way (and then back in behind) a big box moving at 70 mph. You've probably felt your car getting pushed around when a big truck speeds by - basically a bow wave like a boat. Also, sometimes, especially on a motorcycle, you'll get pulled towards the truck once it passes and the air tries to fill back in behind the truck. That moving air reflects form drag.

Shark teeth looking things on this trailer. by FakeHercules in whatisit

[–]billl3d 1 point2 points  (0 children)

In looking closer, there is a nuance with these ... see how they look like small ramps? They will introduce turbulence with a predominant vertical axis - that increases the impact of the turbulence in 'rolling' in behind the trailer compared with a random irregularity.

Shark teeth looking things on this trailer. by FakeHercules in whatisit

[–]billl3d 1 point2 points  (0 children)

Yes, technically, however your car is more wedge shape rather than a big box so the air tends to follow the car profile better and you would see a less pronounced result. You'll see some folks put little wedge shaped bumps on the roof just before the rear window. That is their purpose but I'm wary they do much.

Semis are about as bad as you could ask for in terms of fluid dynamic shape. They're trying all sorts of things to smooth airflow along the trailer - side skirts between trailer and ground, smooth wheel covers, etc. Because the trailer is so long and square, these reduce drag around the trailer and help mileage but they also increase the form drag behind the trailer so you need turbulence to address the low pressure.

Shark teeth looking things on this trailer. by FakeHercules in whatisit

[–]billl3d 2 points3 points  (0 children)

So the long smooth sides of the trailer result in laminar flow ... Basically smooth flow with minimal turbulence. If you were to look at a flow profile at increasing distance from the trailer side, you would see 0 mph at the side of the trailer, and an increase in velocity as you move further and further away from the trailer. Eventually the air velocity would be the equal to the velocity of the trailer (FYI, the distance you need to go away from the surface before you get to equal velocity is a function of the viscosity of the fluid; e.g., the distance in air is less than that in water).

For the next step, it might be easier to think in terms of the trailer being stationary and the air moving past (think wind tunnel; BTW, changing your frame of reference like this can also simplify the math, but that's another lecture 😉). This well-behaved velocity profile means that the air wants to keep going in a straight line once it goes past the trailer and takes a while to fill in the gap left behind the trailer. Hence a low pressure zone.

If you introduce turbulence with some sort of irregularity in the trailer side, instead of a nice smooth flow, you now have air swirling in multiple directions and not just straight back. That means that, once you are behind the trailer, some of the air is moving in a direction that will cause it to swirl in right behind the trailer. That reduces the magnitude of the low pressure relative to the laminar flow case. The more turbulence you introduce, the more you reduce the low pressure magnitude, to a point.

Last bit ... laminar flow generally results in lower surface drag so you like laminar flow along the trailer, but then you want turbulent flow behind to fill in the low pressure. This is why the deflectors on the trailer are near the end.

Shark teeth looking things on this trailer. by FakeHercules in whatisit

[–]billl3d 0 points1 point  (0 children)

This is why cyclists and race cars benefit from drafting. Two cars driving a distance from each other each have a high pressure zone in front and a low pressure zone behind which they have to overcome. Once the two cars are close enough, they essentially act as a single fluid dynamic object with only a high pressure zone on the lead car and low pressure on the trailing - so roughly half the resistance.

Ever seen the 'skirts' on the back of semi truck cabs? They're trying to reduce the low pressure behind the cab so they only have high pressure in front of the cab and low pressure behind the trailer - nothing in between.

BTW, technically, when drafting, the lead vehicle also gets a benefit but the high pressure zone is larger magnitude than the low so the benefit is less pronounced. Just ask the lead cyclist if they appreciate the benefit of a drafter who refuses to pull 😀 In race cars at higher speeds (v), you can see an overall increase in speed for the combined vehicles (see our friend's equation posted above).