A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Home Built
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

twin tail questions



 
 
Thread Tools Display Modes
  #1  
Old August 4th 03, 07:50 PM
Kevin Horton
external usenet poster
 
Posts: n/a
Default twin tail questions

On Mon, 04 Aug 2003 18:13:25 +0000, Chris W wrote:

I got such a good answer on my question about flap design I thought I
would ask another design question. why would a plane that has two
engines have two vertical stabilizers. No in the case of the Aircoupe I
always thought the reason for the twin tail was so that the helical prop
wash wouldn't induce a yaw tendency from the prop wash hitting the
vertical stabilizer/rudder. It is my understanding that the Aircoupe
was designed so you wouldn't need rudder pedals, and the twin tail I
think would have helped that. But on a twin engine, what's the point?
having two vertical stabilizers and two rudders seems significantly more
complicated both structurally and mechanically so why do it if there
isn't some advantage? There must be one I don't know about.


--
Chris Woodhouse


Planes may have multiple vertical stabs for several different reasons.
Some (e.g. the Lockheed Constellation) may have them to facilitate fitting
them in existing hangars without hitting the top of the door opening.

Some multiple engine designs have multiple vertical tails so that one
portion is directly in the prop wash of the operating engine which may
help reduce the minimum control speed following an engine failure. At
least that is what Kelly Johnson says about the twin vertical tails of the
first Lockheed Electra (More Than My Share of it All, Kelly Johnson, pg.
24). And he says that they also acted as end plates on the horizontal
tail, which increased its effectiveness, and improved the static
longitudinal stability - same book, same page).

--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/

Ads
  #2  
Old August 4th 03, 07:52 PM
Bill Daniels
external usenet poster
 
Posts: n/a
Default


"Chris W" wrote in message
...
I got such a good answer on my question about flap design I thought I
would ask another design question. why would a plane that has two
engines have two vertical stabilizers. No in the case of the Aircoupe I
always thought the reason for the twin tail was so that the helical prop
wash wouldn't induce a yaw tendency from the prop wash hitting the
vertical stabilizer/rudder. It is my understanding that the Aircoupe
was designed so you wouldn't need rudder pedals, and the twin tail I
think would have helped that. But on a twin engine, what's the point?
having two vertical stabilizers and two rudders seems significantly more
complicated both structurally and mechanically so why do it if there
isn't some advantage? There must be one I don't know about.


--
Chris Woodhouse


There used to be an argument that, in the event of an engine failure, a
twin-tail twin would have one fin and rudder directly behind the operating
engine, in the prop wash, where it would be more effective.

The more likely reason that the '30s and '40's saw a number of twin and
triple tail aircraft had to do with the low vertical clearance of hangar
doors. A multi-vertical tail aircraft would more likely be able to pass
through the low door opening where a single tail would have to be much
higher and have to be left outside.

Bill Daniels

  #3  
Old August 5th 03, 12:21 PM
Frederick Wilson
external usenet poster
 
Posts: n/a
Default

So why did the P-38 have a twin tail. I think it is a pretty cool
looking bird. I think the bird the "Doolittle Raiders" flew had a twin
tail too.

Fred

Chris W wrote:
I got such a good answer on my question about flap design I thought I
would ask another design question. why would a plane that has two
engines have two vertical stabilizers. No in the case of the Aircoupe I
always thought the reason for the twin tail was so that the helical prop
wash wouldn't induce a yaw tendency from the prop wash hitting the
vertical stabilizer/rudder. It is my understanding that the Aircoupe
was designed so you wouldn't need rudder pedals, and the twin tail I
think would have helped that. But on a twin engine, what's the point?
having two vertical stabilizers and two rudders seems significantly more
complicated both structurally and mechanically so why do it if there
isn't some advantage? There must be one I don't know about.


--
Chris Woodhouse
3147 SW 127th St.
Oklahoma City, OK 73170
405-691-5206

N35 20.492'
W97 34.342'

"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



  #4  
Old August 5th 03, 12:45 PM
Morgans
external usenet poster
 
Posts: n/a
Default


"Frederick Wilson" wrote in message
et...
So why did the P-38 have a twin tail. I think it is a pretty cool
looking bird. I think the bird the "Doolittle Raiders" flew had a twin
tail too.

Fred


The Doolittle raiders flew B-25's, and yes, they had twin tails.

I was not in the head of the designers of the P-38, but as it ended up,
there are a few reasons that they ended up with twin booms (different than
most other twin tails of the time).

In the P-38, everything went towards speed and low drag. They made as
skinny frontal profile as possible. To get lots of HP, thery also wanted it
turbo (or was it super) charged. They put the intercooler (and perhaps the
turbocharger) back behind the engine, and it made it so long, they must have
figured they were halfway back to the tailplane, so why not contine it, and
connect to the tail, and leave off the fuselage. Works for me! G
--
---Jim in NC---


  #5  
Old August 5th 03, 03:28 PM
Morgans
external usenet poster
 
Posts: n/a
Default


"Barnyard BOb --" wrote in message
...

Morgans wrote:

So why did the P-38 have a twin tail. I think it is a pretty cool
looking bird. I think the bird the "Doolittle Raiders" flew had a twin
tail too.

Fred


The Doolittle raiders flew B-25's, and yes, they had twin tails.

+++++++++++++++++++++++++++++++++++

Bzzzzzt.

B-25's have TWIN RUDDERS, not twin tails.

If you do not agree...
The Ercoupe, C-45 and C-60 have twin tails, too.


Barnyard BOb - there is a difference

*****************************
Bzzzzzt.

They have more than twin rudders. Last I looked, they had twin vertical
stabilizers, too.

It all depends how picky you want to get. In one since, the P-38 does not
have twin tails, either. Since the horizontal is connected to both tail
booms, it could be called a Siameese twin tail.(I know that is spelled
wrong, but I am in bed recovering from surgery, and am not getting up to
look it up)

In the end, I will say that the Ercoupe and C-45 and many others have twin
tails, too. g
--
---Jim in NC---


  #6  
Old August 5th 03, 08:12 PM
Ed Sullivan
external usenet poster
 
Posts: n/a
Default

Barnyard BOb -- wrote in message . ..
"Morgans" post/the/group.here.net wrote:

Bzzzzzt.

They have more than twin rudders. Last I looked, they had twin vertical
stabilizers, too.

It all depends how picky you want to get.

+++++++++++++++++++++++++++++++++++++

Don't ever call me "picky" !



Pedantic perhaps?, also I would tend to define the referred to twin
tails as semi-twin empennages since they do share a single horizontal
elevator and stabilizer...so there!

Ed Sullivan, old enough to be anything I want to be.

PETTY is more like it.

======
PICKY -
Excessively meticulous; fussy.

PETTY -
1.Of small importance; trivial: a petty grievance.
2.Marked by narrowness of mind, ideas, or views.
3.Marked by meanness or lack of generosity,
especially in trifling matters.


Barnyard BOb -

  #7  
Old August 5th 03, 10:00 PM
Big John
external usenet poster
 
Posts: n/a
Default

BOb

Here we go again. Disagree/agree but no cussing G

Your right, the B-25 had two of those wiggly things (called rudders).
They also had two verticl stablizers just ahead of the rudders that
did not move.

Your going to confuse some of these young scallywags with your
termonoligy G

Big John


On Tue, 05 Aug 2003 09:04:41 -0500, Barnyard BOb --
wrote:


Morgans wrote:

So why did the P-38 have a twin tail. I think it is a pretty cool
looking bird. I think the bird the "Doolittle Raiders" flew had a twin
tail too.

Fred


The Doolittle raiders flew B-25's, and yes, they had twin tails.

+++++++++++++++++++++++++++++++++++

Bzzzzzt.

B-25's have TWIN RUDDERS, not twin tails.

If you do not agree...
The Ercoupe, C-45 and C-60 have twin tails, too.


Barnyard BOb - there is a difference


  #8  
Old August 5th 03, 10:30 PM
BernadetteTS
external usenet poster
 
Posts: n/a
Default

In article ,
Big John wrote:

Your right, the B-25 had two of those wiggly things (called rudders).
They also had two verticl stablizers just ahead of the rudders that
did not move.

Your going to confuse some of these young scallywags with your
termonoligy G

Big John

So what are they if they are on something like an F-15 or F-18?

Bernadette
  #9  
Old August 6th 03, 03:07 AM
B2431
external usenet poster
 
Posts: n/a
Default

Your right, the B-25 had two of those wiggly things

You have to careful of using technical terminology like that. I have seen twin
wiggly things in mony aircraft, but enough about my wife.

Rumour has it the USAF got rid of the C-121 Constelation because the newer
pilots couldn't handle 3 pieces of tail at the same time.

Dan, U. S. Air Force, retired
  #10  
Old August 6th 03, 06:54 AM
Ken Sandyeggo
external usenet poster
 
Posts: n/a
Default

BernadetteTS wrote in message ...
In article ,
Big John wrote:

Your right, the B-25 had two of those wiggly things (called rudders).
They also had two verticl stablizers just ahead of the rudders that
did not move.

Your going to confuse some of these young scallywags with your
termonoligy G

Big John

So what are they if they are on something like an F-15 or F-18?

Bernadette


They're not "homebuilt," so no one here will probably care :)

Ken J. - Sandy, Egg Ho
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Pitts questions Wendy Aerobatics 7 February 13th 04 03:48 AM
Accelerated spin questions John Harper Aerobatics 7 August 15th 03 07:08 PM
Homebuilt Aircraft Frequently Asked Questions (FAQ) Ron Wanttaja Home Built 4 August 7th 03 05:12 AM
Oshkosh Get together Roster - Sign in, please! Bruce E. Butts Home Built 4 July 26th 03 11:34 AM
Homebuilt Aircraft Frequently-Asked Questions (FAQ) Ron Wanttaja Home Built 0 July 4th 03 04:50 PM


All times are GMT +1. The time now is 10:46 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Copyright 2004-2020 AviationBanter.
The comments are property of their posters.