Two elementary Qs

[Ramapriya]

1. In the other very well-discussed thread on the turning effect
produced during banking, it was pretty much clear that yaw is almost
inevitable during a bank. So what use the rudder at all? Or even the
tail - surely not merely to house the elevators??

2. Is there any advantage or disadvantage in having engines attached
to the fuselage near the tail section vis-a-vis under the wings? I'd
imagine banking would feel a lot lighter and enjoyable if the engines
weren't there :)

Education welcome, even if the Qs aren't :)

Ramapriya

[C Kingsbury]

"Ramapriya" > wrote in message
om...
> 1. In the other very well-discussed thread on the turning effect
> produced during banking, it was pretty much clear that yaw is almost
> inevitable during a bank. So what use the rudder at all? Or even the
> tail - surely not merely to house the elevators??

"Stick and Rudder" by Langewiesche will answer all of your questions about
how planes fly and how to use that knowledge to fly them. It's still very
much in print and can be purchased from Amazon. I strongly suggest reading
this before spending too much time readign newsgroup threads. Oh, and it is
a very fast and easy read.

* There are definitely still debates about whether Langewiesche got this or
that detail quite right, and whether what we know as "conventional" aircraft
design is truly optimal, but you won't go wrong if you start there. If you
don't learn the "conventional wisdom" first I think it's a lot more likely
you'll get confused in details that are not really critical.

> 2. Is there any advantage or disadvantage in having engines attached
> to the fuselage near the tail section vis-a-vis under the wings? I'd
> imagine banking would feel a lot lighter and enjoyable if the engines
> weren't there :)

In every decision in aviation there are both pluses and minuses.

Having engines closer to the centerline reduces turning effect if one engine
quits. Also allows for a cleaner wing design (potentially) as you can build
the wing without worrying about supporting the weight/thrust of the engine
or all the plumbing for it. Also, on smaller planes ground clearance is an
issue, and there often isn't enough room under the wing to hang an engine.

On the negative, engines in the rear will eat into cabin space. I also
suspect that there are weight distribution issues or some such as you will
notice that above a certain size, big transports have always mounted their
engines under the wings. Also the new prototype HondaJet (6-8 seat bizjet)
does something novel and mounts the engines on pylons *above* the wings.
This provides ground clearance but also allows them to get more usable cabin
space.

-cwk.

[Here to there]

On Wed, 17 Nov 2004 16:20:57 GMT, C Kingsbury > wrote:
> On the negative, engines in the rear will eat into cabin space. I also
> suspect that there are weight distribution issues or some such as you will
> notice that above a certain size, big transports have always mounted their
> engines under the wings. Also the new prototype HondaJet (6-8 seat bizjet)
> does something novel and mounts the engines on pylons *above* the wings.
> This provides ground clearance but also allows them to get more usable cabin
> space.


Just a nit, but above-wing mounting is not really novel. Check out

http://www.airliners.net/search/photo.search?aircraft_genericsearch=VFW%20614&distinct_entry=true

for example. There were also a number of early aircraft that used
above-wing mounting, particularly in seaplanes.

- Rich

[Morgans]

>
> Just a nit, but above-wing mounting is not really novel. Check out
>
>
http://www.airliners.net/search/photo.search?aircraft_genericsearch=VFW%20614&distinct_entry=true
>
> for example.

That is one butt ugly aircraft, IMHO. :-o
--
Jim in NC


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.797 / Virus Database: 541 - Release Date: 11/15/2004

[Chris W]

Here to there wrote:

> Just a nit, but above-wing mounting is not really novel. Check out
>
>http://www.airliners.net/search/photo.search?aircraft_genericsearch=VFW%20614&distinct_entry=true
>
>
>
Is it just or doesn't it look like this one
http://www.airliners.net/open.file/559166/L/ is missing it's right aileron?

--
Chris W

Gift Giving Made Easy
Get the gifts you want & give the
gifts they want this holiday season
http://thewishzone.com

"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety."
-- Benjamin Franklin, 1759 Historical Review of Pennsylvania

[G.R. Patterson III]

Chris W wrote:
>
> Is it just or doesn't it look like this one
> http://www.airliners.net/open.file/559166/L/ is missing it's right aileron?

It's an illusion. The flaps extend past the ailerons on that plane. You can't
see the flaps on the left wing because the fuselage is in the way.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Andrew Sarangan]

(Ramapriya) wrote in news:30a8759c.0411170459.1a14f492
@posting.google.com:

> 1. In the other very well-discussed thread on the turning effect
> produced during banking, it was pretty much clear that yaw is almost
> inevitable during a bank. So what use the rudder at all? Or even the
> tail - surely not merely to house the elevators??

While the weathervaning effect will make the airplane to turn in the
direction of the bank, it may not be sufficient to keep the airplane co-
ordinated. You would need rudder to make up for the difference. This is why
different airplanes need different amounts of rudder in a turn. The adverse
yaw would also need to be counteracted by rudder.


>
> 2. Is there any advantage or disadvantage in having engines attached
> to the fuselage near the tail section vis-a-vis under the wings? I'd
> imagine banking would feel a lot lighter and enjoyable if the engines
> weren't there :)


I would imagine that having engines at the tail would exhibit a less
dramatic yaw with one engine out. I don't believe the engine on the wings
would make the controls feel heavier. The control feel is related to the
weight of the control surfaces and the airflow over them. The weight of the
wing has little do with. In an large airline the control surfaces are
probably driven by hydraulics, which means even less feel of the controls.