LS-4a

[[email protected]]

I completed a weight and balance on my LS-4 and want to put
additional weight in the rear. The weight and balance included the
5.5 lb battery that is in the tail. Anyone have any advice or
experience?

Don (CX)

[Adam]

On May 5, 10:08 pm, wrote:
> I completed a weight and balance on my LS-4 and want to put
> additional weight in the rear. The weight and balance included the
> 5.5 lb battery that is in the tail. Anyone have any advice or
> experience?
>
> Don (CX)

My tailwheel is filled with lead. Works fine for me.

There are brass wheels available commercially from Tost (2kg with
tire)
http://www.wingsandwheels.com/page32.htm

I may also make some molded lead weights and glass them in at the top
of the stab. Or lose some body mass...

/Adam

[noel.wade]

On May 5, 8:56 pm, Adam > wrote:
> On May 5, 10:08 pm, wrote:
>
> > I completed a weight and balance on my LS-4 and want to put
> > additional weight in the rear. The weight and balance included the
> > 5.5 lb battery that is in the tail. Anyone have any advice or
> > experience?
>
> > Don (CX)
>
> My tailwheel is filled with lead. Works fine for me.
>
> There are brass wheels available commercially from Tost (2kg with
> tire)http://www.wingsandwheels.com/page32.htm
>
> I may also make some molded lead weights and glass them in at the top
> of the stab. Or lose some body mass...
>
> /Adam

Top of the stab? I'd check with an authority before installing
something like that - the bending moment you could put on the vertical
stab and the twisting force you're applying to the tail-boom with that
arrangement might not be within the designed limits/loads of the
manufacturer (think about what happens with that weight when you roll
the aircraft). I'm not a manufacturer so I can't say for sure, but I
would think the base of the vertical stab / tail-boom would be a much
better place to put it. *shrug*

--Noel

[[email protected]]

On May 5, 10:56 pm, Adam > wrote:
> On May 5, 10:08 pm, wrote:
>
> > I completed a weight and balance on my LS-4 and want to put
> > additional weight in the rear. The weight and balance included the
> > 5.5 lb battery that is in the tail. Anyone have any advice or
> > experience?
>
> > Don (CX)
>
> My tailwheel is filled with lead. Works fine for me.
>
> There are brass wheels available commercially from Tost (2kg with
> tire)http://www.wingsandwheels.com/page32.htm
>
> I may also make some molded lead weights and glass them in at the top
> of the stab. Or lose some body mass...
>
> /Adam

Don't know exactly what you mean by "glass" them in? I see the brass
wheel - a little pricey. Do you mean that you put lead in the actual
wheel? I hear that replacing the tail battery with more than the
original 5.5 lbs is risky?

Don

[BT]

Don our LS 4 has lead added above the tail wheel just forward of the
rudder.You have to remove the rudder to get it out.
BT

> wrote in message
...
> On May 5, 10:56 pm, Adam > wrote:
>> On May 5, 10:08 pm, wrote:
>>
>> > I completed a weight and balance on my LS-4 and want to put
>> > additional weight in the rear. The weight and balance included the
>> > 5.5 lb battery that is in the tail. Anyone have any advice or
>> > experience?
>>
>> > Don (CX)
>>
>> My tailwheel is filled with lead. Works fine for me.
>>
>> There are brass wheels available commercially from Tost (2kg with
>> tire)http://www.wingsandwheels.com/page32.htm
>>
>> I may also make some molded lead weights and glass them in at the top
>> of the stab. Or lose some body mass...
>>
>> /Adam
>
> Don't know exactly what you mean by "glass" them in? I see the brass
> wheel - a little pricey. Do you mean that you put lead in the actual
> wheel? I hear that replacing the tail battery with more than the
> original 5.5 lbs is risky?
>
> Don

[JJ Sinclair]

Noel makes a good point on keeping any added weight as low as
possible. Think about what your tail will experience in a ground-
loop........a large twisting moment, the higher the added weight, the
more twisting.........pretty soon you will twist the tail right off. I
believe the LS-4 has a provision to add tail weight on the lower
rudder hinge bracket, I know the LS-6/7/8 has this. All weight MUST be
secured, as in bolted or glassed in. If you pour in lead shot, the
resin should be thickened with micro-balloons and even then the resin
will tend to pool at the bottom. Adding more resin after the first has
cured and a layer of cloth over the lead shot will keep everything in
place.
Hope this helps,
JJ

noel.wade wrote:
> On May 5, 8:56 pm, Adam > wrote:
> > On May 5, 10:08 pm, wrote:
> >
> > > I completed a weight and balance on my LS-4 and want to put
> > > additional weight in the rear. The weight and balance included the
> > > 5.5 lb battery that is in the tail. Anyone have any advice or
> > > experience?
> >
> > > Don (CX)
> >
> > My tailwheel is filled with lead. Works fine for me.
> >
> > There are brass wheels available commercially from Tost (2kg with
> > tire)http://www.wingsandwheels.com/page32.htm
> >
> > I may also make some molded lead weights and glass them in at the top
> > of the stab. Or lose some body mass...
> >
> > /Adam
>
> Top of the stab? I'd check with an authority before installing
> something like that - the bending moment you could put on the vertical
> stab and the twisting force you're applying to the tail-boom with that
> arrangement might not be within the designed limits/loads of the
> manufacturer (think about what happens with that weight when you roll
> the aircraft). I'm not a manufacturer so I can't say for sure, but I
> would think the base of the vertical stab / tail-boom would be a much
> better place to put it. *shrug*
>
> --Noel

[Bob Salvo]

Placing a groove in the middle of the lead weight allows its
installation/removal without having to remove the rudder. (Just place the
rudder in its neutral position so that its tab/seam lines up with the
groove.)
Bob

"BT" > wrote in message
...
> Don our LS 4 has lead added above the tail wheel just forward of the
> rudder.You have to remove the rudder to get it out.
> BT

[Adam]

On May 5, 11:09*pm, "noel.wade" > wrote:
> On May 5, 8:56 pm, Adam > wrote:
>
>
>
>
>
> > On May 5, 10:08 pm, wrote:
>
> > > I completed *a weight and balance on my LS-4 and *want to put
> > > additional weight in the rear. *The weight and balance included the
> > > 5.5 lb battery that is in the tail. *Anyone have any advice or
> > > experience?
>
> > > Don (CX)
>
> > My tailwheel is filled with lead. Works fine for me.
>
> > There are brass wheels available commercially from Tost (2kg with
> > tire)http://www.wingsandwheels.com/page32.htm
>
> > I may also make some molded lead weights and glass them in at the top
> > of the stab. Or lose some body mass...
>
> > /Adam
>
> Top of the stab? *I'd check with an authority before installing
> something like that - the bending moment you could put on the vertical
> stab and the twisting force you're applying to the tail-boom with that
> arrangement might not be within the designed limits/loads of the
> manufacturer (think about what happens with that weight when you roll
> the aircraft). *I'm not a manufacturer so I can't say for sure, but I
> would think the base of the vertical stab / tail-boom would be a much
> better place to put it. **shrug*
>
> --Noel- Hide quoted text -
>
> - Show quoted text -

In my case the sailplane is a Jantar Standard 2. Indeed it is better
to put it as close to the boom axis as possible. As far as real world
experience, the Brazilians have been putting as much as 8 pounds of
lead at the top of the stab on their fleet of Jantars for 20 years
with no ill effect. They also place lead strips on a fin rib accecible
when the rudder is removed. And some have 3 liter water tanks
installed.

In the case of my tailwheel, molten lead was simply poured in the rim
recesses on both sides. No epoxy/lead shot was used.

/Adam

[Ramy]

On May 6, 6:07*am, JJ Sinclair > wrote:
> Noel makes a good point on keeping any added weight as low as
> possible. Think about what your tail will experience in a ground-
> loop........a large twisting moment, the higher the added weight, the
> more twisting.........pretty soon you will twist the tail right off. I
> believe the LS-4 has a provision to add tail weight on the lower
> rudder hinge bracket, I know the LS-6/7/8 has this. All weight MUST be
> secured, as in bolted or glassed in. If you pour in lead shot, the
> resin should be thickened with micro-balloons and even then the resin
> will tend to pool at the bottom. Adding more resin after the first has
> cured and a layer of cloth over the lead shot will keep everything in
> place.
> Hope this helps,
> JJ
>
>
>
> noel.wade wrote:
> > On May 5, 8:56 pm, Adam > wrote:
> > > On May 5, 10:08 pm, wrote:
>
> > > > I completed *a weight and balance on my LS-4 and *want to put
> > > > additional weight in the rear. *The weight and balance included the
> > > > 5.5 lb battery that is in the tail. *Anyone have any advice or
> > > > experience?
>
> > > > Don (CX)
>
> > > My tailwheel is filled with lead. Works fine for me.
>
> > > There are brass wheels available commercially from Tost (2kg with
> > > tire)http://www.wingsandwheels.com/page32.htm
>
> > > I may also make some molded lead weights and glass them in at the top
> > > of the stab. Or lose some body mass...
>
> > > /Adam
>
> > Top of the stab? *I'd check with an authority before installing
> > something like that - the bending moment you could put on the vertical
> > stab and the twisting force you're applying to the tail-boom with that
> > arrangement might not be within the designed limits/loads of the
> > manufacturer (think about what happens with that weight when you roll
> > the aircraft). *I'm not a manufacturer so I can't say for sure, but I
> > would think the base of the vertical stab / tail-boom would be a much
> > better place to put it. **shrug*
>
> > --Noel- Hide quoted text -
>
> - Show quoted text -

I flew years with 3 pounds of lead shot secured in a bag at the top of
the vertical fin above the battery cover (removed the black foam to
make more space). My local authority was ok with that and I never had
a problem, but also never ground looped.

Ramy

[noel.wade]

> I flew years with 3 pounds of lead shot secured in a bag at the top of
> the vertical fin above the battery cover (removed the black foam to
> make more space). My local authority was ok with that and I never had
> a problem, but also never ground looped.
>
> Ramy

The bottom line is that cantilevering that kind of weight on the top
of the tail is just not something that the aircraft designers and
engineers anticipated. The structure wasn't designed for it - so just
because it has worked doesn't mean that it won't fail in the future,
or that it works on all gliders.

Disregarding structure, there are performance reasons to keep the mass
concentrated down in the fuselage. The closer to the center of
rotation that you place some mass, the less force it takes to put that
mass into motion.

Here's a thought-experiment: Imagine rolling the aircraft. Imagine
looking at the airplane from behind as it executes a perfect aileron
roll. If you put the weight down low in the tail-boom, the rest of
the tail rotates *around* that mass and it doesn't have to travel very
far or move very fast. If it was way out at the tip of the tail, it
would move through a much bigger circle over the same time period.
That means it travels farther and has to move faster. It takes energy
to start and stop the movement of that mass.

In short: Handling is going to be less crisp and it will be harder to
make subtle attitude corrections with a bunch of mass out at the tip
of the tail (or the tip of a wing, or any extreme end of the glider).

Take care,

--Noel

[Greg Arnold[_2_]]

noel.wade wrote:
>> I flew years with 3 pounds of lead shot secured in a bag at the top of
>> the vertical fin above the battery cover (removed the black foam to
>> make more space). My local authority was ok with that and I never had
>> a problem, but also never ground looped.
>>
>> Ramy
>
> The bottom line is that cantilevering that kind of weight on the top
> of the tail is just not something that the aircraft designers and
> engineers anticipated. The structure wasn't designed for it - so just
> because it has worked doesn't mean that it won't fail in the future,
> or that it works on all gliders.
>
> Disregarding structure, there are performance reasons to keep the mass
> concentrated down in the fuselage. The closer to the center of
> rotation that you place some mass, the less force it takes to put that
> mass into motion.
>
> Here's a thought-experiment: Imagine rolling the aircraft. Imagine
> looking at the airplane from behind as it executes a perfect aileron
> roll. If you put the weight down low in the tail-boom, the rest of
> the tail rotates *around* that mass and it doesn't have to travel very
> far or move very fast. If it was way out at the tip of the tail, it
> would move through a much bigger circle over the same time period.
> That means it travels farther and has to move faster. It takes energy
> to start and stop the movement of that mass.
>
> In short: Handling is going to be less crisp and it will be harder to
> make subtle attitude corrections with a bunch of mass out at the tip
> of the tail (or the tip of a wing, or any extreme end of the glider).
>
> Take care,
>
> --Noel


But glider designers DO put the substantial mass of a battery at the tip
of the tail.

[noel.wade]

On May 6, 3:27 pm, Greg Arnold > wrote:
>
> But glider designers DO put the substantial mass of a battery at the tip
> of the tail.

Only on a couple of glider models, and you should always check to
ensure that it was part of the original design.

It is likely that specific battery sizes and weights were assumed.
Simply adding lead or other weight (beyond the battery) is NOT what
the glider-designers had in mind!

The bottom line is that adding weight at the top of the vertical fin
has no "up-side" versus installing the weight at the aft end of the
tail-boom near the tailwheel/skid. But it has a LOT of potential down-
sides, when its stuck way up on the top of the fin!

So why? Just because its convenient? The time it takes to get the
rudder off of most gliders (to install the weight properly) is
negligible.

--Noel

[[email protected]]

On May 6, 7:54*pm, "noel.wade" > wrote:
> On May 6, 3:27 pm, Greg Arnold > wrote:
>
>
>
> > But glider designers DO put the substantial mass of a battery at the tip
> > of the tail.
>
> Only on a couple of glider models, and you should always check to
> ensure that it was part of the original design.
>
> It is likely that specific battery sizes and weights were assumed.
> Simply adding lead or other weight (beyond the battery) is NOT what
> the glider-designers had in mind!
>
> The bottom line is that adding weight at the top of the vertical fin
> has no "up-side" versus installing the weight at the aft end of the
> tail-boom near the tailwheel/skid. *But it has a LOT of potential down-
> sides, when its stuck way up on the top of the fin!
>
> So why? *Just because its convenient? *The time it takes to get the
> rudder off of most gliders (to install the weight properly) is
> negligible.
>
> --Noel

Check the flight manual for your particular glider.
My ASW 24 is designed to accept up to 13.24 pounds of ballast in the
battery / trim box at the top of the fin.

[JJ Sinclair]

OK, story time...........shortly after I gently touched down on the
edge of a barley field, I watched a Discus land a bit deeper in the
barley. He caught a wing tip and spun around 90 degrees. The left wing
was down but the fin and stab laid over (right) a good 30 degrees.
Then it just sat there and shook for several seconds. I believe he
came within a nats-hair of breaking the boom. Now lets add several
pounds of lead to the top of the fin and repeat this little
experiment.......................
JJ

wrote:
> On May 6, 7:54�pm, "noel.wade" > wrote:
> > On May 6, 3:27 pm, Greg Arnold > wrote:
> >
> >
> >
> > > But glider designers DO put the substantial mass of a battery at the tip
> > > of the tail.
> >
> > Only on a couple of glider models, and you should always check to
> > ensure that it was part of the original design.
> >
> > It is likely that specific battery sizes and weights were assumed.
> > Simply adding lead or other weight (beyond the battery) is NOT what
> > the glider-designers had in mind!
> >
> > The bottom line is that adding weight at the top of the vertical fin
> > has no "up-side" versus installing the weight at the aft end of the
> > tail-boom near the tailwheel/skid. �But it has a LOT of potential down-
> > sides, when its stuck way up on the top of the fin!
> >
> > So why? �Just because its convenient? �The time it takes to get the
> > rudder off of most gliders (to install the weight properly) is
> > negligible.
> >
> > --Noel
>
> Check the flight manual for your particular glider.
> My ASW 24 is designed to accept up to 13.24 pounds of ballast in the
> battery / trim box at the top of the fin.

[Andy[_1_]]

On May 7, 6:36*am, JJ Sinclair > wrote:
> Then it just sat there and shook for several seconds. I believe he
> came within a nats-hair of breaking the boom. Now lets add several
> pounds of lead to the top of the fin and repeat this little
> experiment.......................
> JJ


I know of a Std Jantar that was found to have a floppy empenage
(reduced torsional stiffness in the boom just forward of the fin).
Turned out there was internal damage at the base of the fin even
though there was no external skin cracking. The glider had been
involved in a ground loop but had flown many hours afterwards with no
suspicion that it was unsafe.

So if you ground loop, with or without fin ballast, don't assume
nothing was damaged just because the tail didn't separate.

Andy