CG Hook Location Computation

I forgot to add, the CG is usually (but not necessarily always) figured
to be the leading edge of the wing and all calculations are made from
the CG. It is where everything in front of the CG and everything
behind the CG balance. See the Weight and Balance calculations for the
2-33 (or any glider), which should be in the glider's flight manual.

Raul

wrote:
When the aircraft manf has not done the research or made any
recommendations - how is the location for a CG hook computed?

One example - the SGS 2-33 installations I have seen (not factory) seem
to be far ahead of the actual CG.

TNX

Michael

raulb wrote:
I forgot to add, the CG is usually (but not necessarily always) figured
to be the leading edge of the wing and all calculations are made from
the CG. It is where everything in front of the CG and everything
behind the CG balance. See the Weight and Balance calculations for the
2-33 (or any glider), which should be in the glider's flight manual.


My handy SGS 2-33 manual shows the reference point for CG computations
to be Station "0", just slightly aft of the nose of the aircraft. The
"Datum", or leading edge of the wing at the root is at Sta. 66.34".

The CG range for all 2-33's when flown is Station 78.20" to Sta. 86.10",
or 7.9" wide, from 11.86" aft of the Datum (wing root L.E.) to 19.76"
aft of the Datum.

The empty weight CG for a representative 2-33 is around 96.0", with the
main gear axle center at 88.75", which is why 2-33's sit tail low on the
ground when empty.

The text of the 2-33 manual mentions both a "forward" and "CG release",
but the only release I've ever seen on a 2-33 is just ahead of the skid,
and I suppose that is what Schweizer calls a "CG" release on the 2-33.
The skid would interfere with a release nearer the forward edge of the
CG range.

Anybody here know where the "forward release" on a 2-33 would be?


Jack

Jack wrote:
raulb wrote:
I forgot to add, the CG is usually (but not necessarily always) figured
to be the leading edge of the wing and all calculations are made from
the CG. It is where everything in front of the CG and everything
behind the CG balance. See the Weight and Balance calculations for the
2-33 (or any glider), which should be in the glider's flight manual.


ground when empty.

The text of the 2-33 manual mentions both a "forward" and "CG release",
but the only release I've ever seen on a 2-33 is just ahead of the skid,
and I suppose that is what Schweizer calls a "CG" release on the 2-33.
The skid would interfere with a release nearer the forward edge of the
CG range.

Anybody here know where the "forward release" on a 2-33 would be?


Jack
My handy SGS 2-33 manual shows the reference point for CG computations
to be Station "0", just slightly aft of the nose of the aircraft. The
"Datum", or leading edge of the wing at the root is at Sta. 66.34".

The CG range for all 2-33's when flown is Station 78.20" to Sta. 86.10",
or 7.9" wide, from 11.86" aft of the Datum (wing root L.E.) to 19.76"
aft of the Datum.

The empty weight CG for a representative 2-33 is around 96.0", with the
main gear axle center at 88.75", which is why 2-33's sit tail low on the

We had a 2-33 at PGC with what I understood was a factory kit. As I
recollect, it was installed on the right side of the ship, alongside of
the skid about the skid midpoint. The ship was N33966 - I don't
remember who bought it, but you can look it up and perhaps get more
information.

Chip F.

Jack wrote:

The text of the 2-33 manual mentions both a "forward" and "CG release",
but the only release I've ever seen on a 2-33 is just ahead of the skid,
and I suppose that is what Schweizer calls a "CG" release on the 2-33.
The skid would interfere with a release nearer the forward edge of the
CG range.

Anybody here know where the "forward release" on a 2-33 would be?


Excuse me? Somehow I do not think you understand the term "CG."

No matter what Schweizer calls it, the "nose hook" is not located at
the Center of Gravity (CG) and thus cannot possibly be the "CG hook."

The nose hook is in front of the skid. The compensation hook is
mounted somewhere mid-skid and offset to the side slightly so as to
avoid the skid. The CG hook is mounted on (or very close to) the
Center of Gravity possibly also offset so as to avoid the skid. I have
a friend with a 2-33 that has all 3 hooks.

raulb wrote:

The compensation hook is
mounted somewhere mid-skid and offset to the side slightly so as to
avoid the skid. The CG hook is mounted on (or very close to) the
Center of Gravity possibly also offset so as to avoid the skid. I have
a friend with a 2-33 that has all 3 hooks.

Curiouser and curiouser.

Three hooks now, is it?

Can you get your friend to post photos?


Jack

Jack wrote:
raulb wrote:

The compensation hook is

Curiouser and curiouser.

Three hooks now, is it?

Can you get your friend to post photos?

Do you own homework. See the diagram in The American Soaring Handbook,
volume 3, Ground Launching, page 10.

They call the "compensation hook" the "compromise hook." Symantics.

raulb wrote:

Do you own homework. See the diagram in The American Soaring Handbook,
volume 3, Ground Launching, page 10.

Thanks for your help, raulb.


Jack