Primary Glider Drawings

To All:

As promised, I've began posting drawings of primary glider(s). You
will find them in PRIMARY_GLIDERS Group, in the FILES archive, in the
Folder 'The Northrup Primary Glider.' So far I've only posted a few.
The others will be posted as time -- and my medical condition --
permits.

The drawings are in DeltaCAD's native format; the file suffix is .dc.
DeltaCAD will give you a free but time-crippled copy of their
software. It is about 6megabytes and will run on any WINDOWS system
from 95 on up. Most of the drawings are of fittings. The main
advantage in using a CAD format is that the drawings may be printed
full-scale, allowing them to be used as patterns.

I believe I have drawings for five different primaries but so far I've
only found the Northrup and the SG-38. These use a wooden fuselage.
Other primaries use welded steel tubing.

'Northrup' is a seed company. A member of the Northrup family
imported a primary glider after seeing them being flown in Europe
(circa 1929) and 'Northrup' became synonymous with 'primary glider.'
The drawings depict one of the earliest configurations of the primary
glider, in which the wings are wire-braced. Later versions have a
strut-braced wing.

NORTHROP refers to John Northrop, the American engineer best known for
his flying wings.

-R.S.Hoover

On Sat, 4 Oct 2008 09:30:25 -0700 (PDT), "
wrote:

To All:

As promised, I've began posting drawings of primary glider(s). You
will find them in PRIMARY_GLIDERS Group, in the FILES archive, in the
Folder 'The Northrup Primary Glider.' So far I've only posted a few.
The others will be posted as time -- and my medical condition --
permits.

The drawings are in DeltaCAD's native format; the file suffix is .dc.
DeltaCAD will give you a free but time-crippled copy of their
software. It is about 6megabytes and will run on any WINDOWS system
from 95 on up. Most of the drawings are of fittings. The main
advantage in using a CAD format is that the drawings may be printed
full-scale, allowing them to be used as patterns.

I believe I have drawings for five different primaries but so far I've
only found the Northrup and the SG-38. These use a wooden fuselage.
Other primaries use welded steel tubing.

'Northrup' is a seed company. A member of the Northrup family
imported a primary glider after seeing them being flown in Europe
(circa 1929) and 'Northrup' became synonymous with 'primary glider.'
The drawings depict one of the earliest configurations of the primary
glider, in which the wings are wire-braced. Later versions have a
strut-braced wing.

NORTHROP refers to John Northrop, the American engineer best known for
his flying wings.

-R.S.Hoover
************************************************** ************************

Veeduber

What would it take to convert a primary into a basic soaring machine
(35+ to 1)?. I know sitting in open would be a high drag problem
but.......maybe a very light none structual wood frame cloth covered
to stream line fuselage?

Could a machine be made very cheap and quick this way to permit
soaring local around the air patch?

Also designed to pull (or fold) the wings in a few minutes (Solo) and
load to haul home for storage (and work/repair) in the garage?

To continue with a War Story.

I had a young Japanese man working for me in Japan. In discussion with
him he said he was in pilot training when war ended.

He said that the initial training was in primary gliders and that the
instructor stood on the welded steel tubing just behind the pilot in
training. The instructor wore the classical Japanese socks, like they
wore with 'zories', and gripped the tubing between the big toe and
first toe and held on to a vertical piece of the tubing.

Since the instructor couldn't reach the controls in front of pilot, he
gave voice instructions over the shoulder until he got off and let the
pilot go solo.

Launch was typical V of shock cord which two groups would hold and run
down the hill to extend. When they had stretched the shock cord
enough, the glider would be released and launched down the hill just a
few feet off the ground as sink rate and slope of hill was about the
same.

As was typical of Primary Glider flying, all the pilots had to help
launch and pull the gliders back up the hill.


Big John

Tech Support wrote in message
...

What would it take to convert a primary into a basic soaring machine
(35+ to 1)?.

Start over and design a completly different machine with a completely
different mission! Most true training gliders have an L/D of considerably less
than 35 to one.

I know sitting in open would be a high drag problem
but.......maybe a very light none structual wood frame cloth covered
to stream line fuselage?

The PW-2 Gapa is about as far as one can go with the primary concept. It is
capable of thermaling and extended (albeit local) flights given the right
conditions, but has a stated L/D of only 12.5.
http://www.soaravenal.com/gapa.htm I almost had access to one once. My
employer ended up with a nice one, but never got it licensed.

Vaughn

Veeduber

What would it take to convert a primary into a basic soaring machine
(35+ to 1)?. I know sitting in open would be a high drag problem
but.......maybe a very light none structual wood frame cloth covered
to stream line fuselage?

Could a machine be made very cheap and quick this way to permit
soaring local around the air patch?

Also designed to pull (or fold) the wings in a few minutes (Solo) and
load to haul home for storage (and work/repair) in the garage?


Big John,

35 to 1 and open cockpit don't coexist. Light weigh does not improve glider
ratio. In order to get anything near 35 to 1 in a homebuilt you must build
something like my Schreder HP-14.
(http://www.soaridaho.com/Schreder/HP-14/N990/N990.html)

Wayne
http://www.soaridaho.com/Schreder

"Wayne Paul" wrote in message
...
Veeduber

What would it take to convert a primary into a basic soaring machine
(35+ to 1)?. I know sitting in open would be a high drag problem
but.......maybe a very light none structual wood frame cloth covered
to stream line fuselage?

Could a machine be made very cheap and quick this way to permit
soaring local around the air patch?

Also designed to pull (or fold) the wings in a few minutes (Solo) and
load to haul home for storage (and work/repair) in the garage?


Big John,

35 to 1 and open cockpit don't coexist. Light weigh does not improve
glider ratio. In order to get anything near 35 to 1 in a homebuilt you
must build something like my Schreder HP-14.
(http://www.soaridaho.com/Schreder/HP-14/N990/N990.html)

Wayne
http://www.soaridaho.com/Schreder


Another option is to take a look at the SLA gliders like the Sparrowhawk.
These have an airframe weight of less than 200 pounds. In some cases the
glider weighs less than the pilot! In spite of their light and relatively
simple construction, they exhibit impressive performance in excess of 30:1.
See: http://www.windward-performance.com/

I doubt that they will ever exceed the 40:1 common among the larger 15 meter
gliders but they're a far better solution than a 'primary glider'.

"Bill Daniels" bildan@comcast-dot-net wrote in message
. ..

"Wayne Paul" wrote in message
...
Veeduber

What would it take to convert a primary into a basic soaring machine
(35+ to 1)?. I know sitting in open would be a high drag problem
but.......maybe a very light none structual wood frame cloth covered
to stream line fuselage?

Could a machine be made very cheap and quick this way to permit
soaring local around the air patch?

Also designed to pull (or fold) the wings in a few minutes (Solo) and
load to haul home for storage (and work/repair) in the garage?


Big John,

35 to 1 and open cockpit don't coexist. Light weigh does not improve
glider ratio. In order to get anything near 35 to 1 in a homebuilt you
must build something like my Schreder HP-14.
(http://www.soaridaho.com/Schreder/HP-14/N990/N990.html)

Wayne
http://www.soaridaho.com/Schreder


Another option is to take a look at the SLA gliders like the Sparrowhawk.
These have an airframe weight of less than 200 pounds. In some cases the
glider weighs less than the pilot! In spite of their light and relatively
simple construction, they exhibit impressive performance in excess of
30:1. See: http://www.windward-performance.com/

I doubt that they will ever exceed the 40:1 common among the larger 15
meter gliders but they're a far better solution than a 'primary glider'.

Well, I really liked what I saw and read, and might even fit in it quite
comfortably.

However, although I should probably leave this to the experienced glider
pilots, I think that it is probably two steps up from the primary glider. I
also thing that the primary glider, or a modern analog with a little better
occupant protection (especially legs), still has a very usefull place as a
true basic trainer. Personally, having only one glider demo ride many years
ago, I would prefer to start with a much lower L/D--especially for the first
few solo areo-tows!

Sorry about the lack of hubris, but self preservation does have some merit.
Peter

"Peter Dohm" wrote in message
. ..
"Bill Daniels" bildan@comcast-dot-net wrote in message
. ..

"Wayne Paul" wrote in message
...
Veeduber

What would it take to convert a primary into a basic soaring machine
(35+ to 1)?. I know sitting in open would be a high drag problem
but.......maybe a very light none structual wood frame cloth covered
to stream line fuselage?

Could a machine be made very cheap and quick this way to permit
soaring local around the air patch?

Also designed to pull (or fold) the wings in a few minutes (Solo) and
load to haul home for storage (and work/repair) in the garage?


Big John,

35 to 1 and open cockpit don't coexist. Light weigh does not improve
glider ratio. In order to get anything near 35 to 1 in a homebuilt you
must build something like my Schreder HP-14.
(http://www.soaridaho.com/Schreder/HP-14/N990/N990.html)

Wayne
http://www.soaridaho.com/Schreder


Another option is to take a look at the SLA gliders like the Sparrowhawk.
These have an airframe weight of less than 200 pounds. In some cases the
glider weighs less than the pilot! In spite of their light and
relatively simple construction, they exhibit impressive performance in
excess of 30:1. See: http://www.windward-performance.com/

I doubt that they will ever exceed the 40:1 common among the larger 15
meter gliders but they're a far better solution than a 'primary glider'.

Well, I really liked what I saw and read, and might even fit in it quite
comfortably.

However, although I should probably leave this to the experienced glider
pilots, I think that it is probably two steps up from the primary glider.
I also thing that the primary glider, or a modern analog with a little
better occupant protection (especially legs), still has a very usefull
place as a true basic trainer. Personally, having only one glider demo
ride many years ago, I would prefer to start with a much lower
L/D--especially for the first few solo areo-tows!

Sorry about the lack of hubris, but self preservation does have some
merit.
Peter


Let me throw in a slightly controversial idea.

Low L/D, taken in isolation, offers no benefit whatsoever in a trainer. In
fact, higher L/D is a safety feature that gets an inexperienced pilot back
to the runway after a bad judgement call. In spite of this, there is an
instinctive reaction among most glider pilots to inversely relate L/D and
safe handling qualities.

I would claim they are directly related. A glider carefully engineered for
great handling and occupant protection will also have a good L/D. As an
example, I would offer the excellent Schleicher ASK-21 as well as several
other modern composite trainers.

The little Sparrowhawk is not really a trainer. It's a single seater that
requires a pilot to approach it with considerable training in his logbook.
It is, however, an excellent minimalist design.

"Primary gliders" were an expedient developed in an environment that lacked
adequate two-seat trainers. They were abandoned with great relief as soon
as usable 2-seater trainers became available. Today, there are a great
number of excellent 2-seat trainers and qualified instructors. Only a fool
would try to learn flying in a "Primary".

"Bill Daniels" bildan@comcast-dot-net wrote in message
. ..
Let me throw in a slightly controversial idea.

Low L/D, taken in isolation, offers no benefit whatsoever in a trainer.
In fact, higher L/D is a safety feature that gets an inexperienced pilot
back to the runway after a bad judgement call. In spite of this, there is
an instinctive reaction among most glider pilots to inversely relate L/D
and safe handling qualities.

I would claim they are directly related. A glider carefully engineered
for great handling and occupant protection will also have a good L/D. As
an example, I would offer the excellent Schleicher ASK-21 as well as
several other modern composite trainers.

The little Sparrowhawk is not really a trainer. It's a single seater that
requires a pilot to approach it with considerable training in his logbook.
It is, however, an excellent minimalist design.

"Primary gliders" were an expedient developed in an environment that
lacked adequate two-seat trainers. They were abandoned with great relief
as soon as usable 2-seater trainers became available. Today, there are a
great number of excellent 2-seat trainers and qualified instructors. Only
a fool would try to learn flying in a "Primary".

Bill,

I have read your posts here and rec.aviation.soaring. To date I have never
disagreed with your opinions. Here again, I am in total agreement.

Wayne
http://www.soaridaho.com/Schreder

"Bill Daniels" bildan@comcast-dot-net wrote in message
. ..
Low L/D, taken in isolation, offers no benefit whatsoever in a trainer. In
fact, higher L/D is a safety feature that gets an inexperienced pilot back to
the runway after a bad judgement call.

I MOSTLY agree (see below) ...

In spite of this, there is an instinctive reaction among most glider pilots to
inversely relate L/D and safe handling qualities.

A high L/D implies a very slippery airframe. Unless any high L/D glider
trainer is very carefully engineered, a moment's inattention to any nose-down
attitude could quickly result in airspeeds beyond Vne.

Only a fool would try to learn flying in a "Primary".

I don't know that I go quite that far, but as I have said before, I would not
recommend a primary as a flight training aircraft. That said, building one
might be a great learning experience at the EAA chapter level and flying it
would be a great activity for the annual chapter picnic.

Vaughn

On Sun, 5 Oct 2008 09:18:21 -0600, "Bill Daniels" bildan@comcast-dot-net
wrote:

I would claim they are directly related. A glider carefully engineered for
great handling and occupant protection will also have a good L/D.

Bill, I don't have a dog in this hunt, but: Unless you're using a different
definition of "occupant protection" than I am, I disagree. Adding a steel crash
cage to a glider cockpit will increase occupant protection, but has a negative
effect on the aircraft weight without improving the aerodynamic performance.

If your intent was more along the lines "occupant encapsulation" (e.g.,
enclosing the pilot to minimize aerodynamic drag), then we're in agreement. but
it would be possible to put the pilot in an eggshell that would achieve the
aerodynamics without significantly improving the crash protection....

Ron Wanttaja