awesome John......
not too VC so we can't say too much here.
But that's  why the P-38 Lightening has counter-rotating props.

I hadn't ever thought that tail draggers never have variable pitch props ,
if that's what you said.
If I had to guess on a test, I'd guess that there are taildragger aircraft
with variable pitch props.
I can't imagine a P-51 Mustang having a constant pitch prop - just doesn't
sound right.

thanks for the good words too, on the one wheel drive thing.

the way I learned the saying is.,....................... 'Flying is hours
and hours of boredom punctuated by moments of sheer terror."
your redentition  is probably more correct.

let's see.............( VC )
" Driving a Vanagon is hours and hours of pure pleasure,
intersped with periods of sometimes challenging repair and rescue. "

needs some work to get it more elegant/poetic .

Scott

----- Original Message -----

From: "John Rodgers" <inua@charter.net>
To: "Scott Daniel - Turbovans" <scottdaniel@TURBOVANS.COM>
Cc: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, April 12, 2009 7:17 PM
Subject: Re: Only ONE drive wheel?

> Scott,
>
> Very good description and insight into what happens with the standard
> differential.
>
> Viva la Posi-trac!!!
>
> Nice "Tip's and Trick's" on how to get a "poor man's limited slip
> differential". It's akin to letting some air out of the tires to drive off
> a sandy beach or get out of your home  garage when to save money at home
> you switched to  bigger rims and tires only to discover you can't get out
> of your garage any more, or perhaps to go under a really low bridge.
>
> To expand on the aircraft propeller thing - whether single or multi-engine
> aircraft type - the crankshaft is for the most part horizontal to the
> ground or the earths surface plane in aircraft with tricycle landing gear.
> On tail-draggers there is another element involved which I won't mention
> here. In the tri-gear machines the blade angle on a propeller is the same
> on all blades, and all rotate in the same plane - 90 degrees to the
> crankshaft - and 90 degrees to the relative plane of the earths surface.
> However, when the pilot rotates the nose of the airplane skyward, the
> angle of the propeller and the crankshaft changes relative to the earths
> plane. Given that most modern American made aircraft engines rotate to the
> right as seen from the pilots seat, the propeller blade on the right will
> be going down while blades on the left will be going up. Because of the
> change in the angle relative to the ground, the propeller blade on the
> right going down takes a much bigger bite of the air, than the blade on
> the left coming up. This produces much greater thrust on the right than
> the left, and the airplane tries hard to turn left all through the climb
> to altitude. The pilot is trained to overcome this and kept the airplane
> under directional control, but it adds an additional load on him to take
> care of the airplane. Additionally, the left turning tendency also tends
> to drive the right wing forward faster, allowing the left wing to drop
> back relative to the path of flight. The result is increased lift on the
> right wing, and reduced lift on the left wing. With more lift on the right
> wing and less on the left, the airplane has a tendency to roll to the
> left. So there you have it. Left turning, and left rolling, all of which a
> pilot is trained to control very precisely. But it can make for some
> interesting moments under certain conditions. But it makes a pilots life
> interesting to say the least.  It is said that a pilots flying life is
> filled with thousands of hours of relative boredom, interspersed with
> moments of sheer terror!!!  I'm here to tell you it is so true, so true!
>
> Engines, crankshafts, torque, left wheels lifting, right wheel getting a
> better bite on the ground, rotating propellers getting a bigger bite on
> the right and less on  the other ---- it's all got it's similarities - and
> it all derived from  the same physics. Vanagons and airplanes - who would
> have thought there could be such similarities.
>
> Regards.
>
> John Rodgers
> 88 GL Driver
>
> Scott Daniel - Turbovans wrote:
>> what you experienced is perfectly normal.
>> let's see.........
>> the differential in the rear end drives both wheels evenly............
>> as long as the van is going straight, and there is equal and good
>> traction
>> for each rear wheel.
>>
>> so it drives both rear wheels..........but either rear wheel is free to
>> turn
>> more revolutions ( like the outside wheel would in a turn ) or just plan
>> spin.
>>
>> saying that the right rear is 'the driven wheel' .......
>> is not true in the hardest sense of the term.
>> What is true, I believe is .........
>> due to the direction of engine rotation ( especially true in a front
>> engine
>> rear drive car ) ....engine and drivetrain  torque tends to lift one rear
>> wheel, and push the other rear wheel downwards.
>>
>> yeah........just thinking about in my head - consider a front engine rear
>> drive car .......engine rotates clockwise when viewed from the front of
>> the
>> engine ......or counterclockwise viewed from the driver's seat.   Viewed
>> from the driver's seat, the body of the car is trying to rotate  opposite
>> the direction of crankshaft rotation .........thus the left rear wheel is
>> lifted slightly and the right rear is driven into the pavement more.
>>
>> this affect is also observable in single engine propeller aircraft, and
>> in
>> single prop boats too. The body of the vehicle tries to twist in the
>> opposite direction of crankshaft rotation, and in a car that tends to
>> drive
>> one side of the vehicle more into the pavement.  It's quite observable in
>> big trucks too .......they really tilt when the jump on the gas
>> ...........the tractor part with no trailer attached .........with all
>> that
>> torque the cab really wants to tilt under a heavy right foot on the go
>> pedal.
>>
>> here's a trick......
>> the 'poor man's limited slip rear differential ' ...........when you're
>> stuck from one wheel spinning..............put the parking brake on half
>> way, or even a little more.
>> the idea is that by making the resistance to turning of both driven
>> wheels
>> roughly the same, drive will be transferred to both wheels, including the
>> one not touching the ground, or slipping on ice etc.
>> Scott
>> www.turbovans.com
>>
>>
>> ----- Original Message -----
>> From: "Brian Doss" <doss88wkndr@ZOOMINTERNET.NET>
>> To: <vanagon@GERRY.VANAGON.COM>
>> Sent: Sunday, April 12, 2009 5:28 PM
>> Subject: Only ONE drive wheel?
>>
>>
>> I have an '88 GL with a manual transmission. I got it stuck backing into
>> an
>> uneven driveway yesterday. Just so happened that I was in a saddle on a
>> hillside, with just enough torsion on the bus to lift the left rear wheel
>> off the ground - and presto - no go. The left wheel spun happily in
>> forward
>> or reverse. What I can't understand is that I thought the right wheel was
>> driven as well - why did it not receive any power? Does this mean
>> something
>> is wrong with my transmission?
>>
>> Thanks for any insight on the matter
>>
>>
>> Brian Doss
>> Butler, PA
>> '88 Weekender, Queequeg
>>
>>
>
>