This is the Beringer 4 disc system, it's supposed to reduce gyroscopic inertia. What do you think ?

Clive W

+1

It's only useful when you have a single disc setup and cannot upgrade to dual discs.

mick wrote on 11/10/10 at 08:40:21:


Then why do they not have control problems on take off?  the wheels are spinning as they leave the ground.  They have got to have gyroscopic influence then too but they don't have problems.  It your statement is correct, the mechanism that was used to spin the wheels must have been on a different axis and it was the influence, not the spinning wheels.

Phelonius

Phelonius wrote on 11/10/10 at 10:19:28:

the wheels will not have that effect if going around in mid air,besides the pilot can apply the breaks after becoming airborne.
that is why the plane will not be effected before landing, only after touchdown.I dont have to ty and convince you ,it's a fact,try and google it.

hope this works. at least I found something.


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At press time, we had received three responses to the reader who wanted to know why aircraft tires aren't configured with wind-catching profiles that would bring the wheels up to air speed before the plane lands (Sensors, January 2000). Here they are:

Why don't airplanes spin up their landing gear wheels to land-speed before touchdown, or why don't tire designers make the tires automatically spin up using air flow?

The best answer I've heard for this perennial question is that adding those huge gyroscopes (each wheel, multiplied by the number of wheels, and then there is the moment to calculate and on and on) to the plane right at the time when quick responsiveness (if a jumbo jet can be quickly responsive) is a safety hazard. It would make the plane unresponsive, and the pilots would no longer have that fingertip control required for maneuvering.

Consider this experiment: take your front bicycle wheel off and hold it by the axle tips between your two hands directly in front of and in line with your body at chest height. Have a friend give it a really good spin-up and then try to run down a winding hallway without hitting anything while maintaining the wheel attitude directly in front of your body--i.e., turn the wheel for every turn you make in the hallway.

See? Now you don't want your pilots trying to do that with a plane they are landing on a short runway with the planes wheels spun up, do you? Especially not with you aboard!


Phelonius, the pilot applied the brakes after take off to stop any  gyroscopic  effect.

Jerry Eichenberger wrote on 11/10/10 at 17:43:30:


get a droid, then you'll know hard typing  

If you try the bicycle wheel expirement remember to tilt the wheel as you turn, the same as leaning the bicycle. Then it will work

Phelonius

I know very little about the "pre-rotators" that were experimented with in the WW II and post war years on large aircraft.

What I do know is that the experiments were discontinued because the added cost and complexity weren't worth the minor savings in tire wear.

Airplane tires have a very short life.  In the 1950s, as jets came into being, with landing speeds in excess of 150 mph, and with still more primitive tire compounds of that era, some airplanes were only getting about 15 landings per tire change.

The issue is that when an airplanes lands, its tires have to speed up from zero to whatever the landing speed is in a fractional of a heartbeat.  That scrubs a tremendous amount of rubber off of the tire.  If you ever look at a runway, you can see what look like skid marks are the ends of the runway - this is the rubber that has been scrubbed off during each landing.  Even today, runways are routinely closed now and then for a day's worth of rubber removal from the pavement.

But as tire compound science developed, tire wear rates were significantly reduced, so the idea of having a device to get the tires rotating before landing just wasn't worth the added cost and complexity.  But I know of no control difficulties found during those experiments, but they may have been there - I just don't know.

Also, back when airplanes routinely landed on grass runways, the problem was no where nearly as big, because a tire will actually "scoot"  or slide some on the grass, since grass has far less friction than pavement, and the tires could come up to speed over a longer period of time with far less scrubbing of the tread.  Of course, nowadays, only the smallest of light airplanes still routinely use grass.

As for pitching baseball curves, sliders, etc. is has a lot more to do with the areodynamics of a baseball and how the balls rotates leaving the pitcher's hand.  We have a doc at our airport who used to be a pitching scout for the NY Yankees.  He gives a wonderful talk to flying groups about the aerodynamics of pitching and his story weaves together aerodynamics with athletic prowess.  As he waves his hand around, it's really neat to see how big a World Series championship ring is.