Weight & Bal Calc ASK-21

[roccos]

Anyone have a simple wt. & bal calc method for ASK-21? The manual is all in German and makes no sense. Power-plane manuals are simple to use with a graph.

[JS]

Perhaps download this manual in English, and look at page 46.
Jim

http://www.williamssoaring.com/fleet/ASK21_manual.pdf

[Matt Herron Jr.]

On Saturday, October 24, 2015 at 5:45:49 AM UTC-7, Skytime wrote:
> Anyone have a simple wt. & bal calc method for ASK-21? The manual is all in German and makes no sense. Power-plane manuals are simple to use with a graph.

May I shamelessly recommend SeeG, a program specifically designed for C/G calculation on gliders, one seat or two. http://www.glideplan.com/styled-2/page12/index.html Simple, fast, and flexible.

Matt Herron

[Burt Compton - Marfa Gliders, west Texas]

Essential: Obtain the Schleicher ASK-21 Flight Manual in english.
It will be specific to your serial number.
Note the manual revisions listed at the Schleicher website.
If you attach the spin weights, consult the recent manual revisions.

Optional: A calculator but only for a specific ASK-21 in Nevada: http://soaringnv.com/WeightBalance.php

Best to develop your own. Consult your A&P / IA.

[Eric Munk]

And as a final thought: there's a fairly recent TM which expands the manual
with new weight-ranges for heavier gliders.

[Dan Marotta]

If you're comfortable with spreadsheets, make your own or borrow an
existing one and modify it for your glider. My LAK-17a came with a
spreadsheet which I've modified to include installation of a flight
computer in the panel and replacing the tail battery with a heavier lead
weight. It also has cells for wing and tail ballast (water) and is
duplicated for 15- and 18-meter spans and baggage compartment load. I
don't know whether it came from the factory or the previous owner, but
it's pretty simple to make. I did one for the company King Air years back.

On 10/24/2015 11:49 AM, Burt Compton - Marfa Gliders, west Texas wrote:
> Essential: Obtain the Schleicher ASK-21 Flight Manual in english.
> It will be specific to your serial number.
> Note the manual revisions listed at the Schleicher website.
> If you attach the spin weights, consult the recent manual revisions.
>
> Optional: A calculator but only for a specific ASK-21 in Nevada: http://soaringnv.com/WeightBalance.php
>
> Best to develop your own. Consult your A&P / IA.
>

--
Dan, 5J

[Matt Herron Jr.]

If you do your own calculations, please be aware of a very common error. Some manuals use a formula for C/G which uses the distance between the main wheel and the tail wheel. Others use a formula that use the distant to the tail wheel from the datum. Either one will work, but if you use the wrong distance to the tail wheel it creates a 3-5% error in the final C/G. It usually goes unnoticed as it is small, but I have seen this even from official W&B sheets.

Matt H

[Per Carlin]

On Sunday, October 25, 2015 at 3:34:21 PM UTC+1, Matt Herron Jr. wrote:
> If you do your own calculations, please be aware of a very common error. Some manuals use a formula for C/G which uses the distance between the main wheel and the tail wheel. Others use a formula that use the distant to the tail wheel from the datum. Either one will work, but if you use the wrong distance to the tail wheel it creates a 3-5% error in the final C/G. It usually goes unnoticed as it is small, but I have seen this even from official W&B sheets.
>
> Matt H

And do NOT trust an old and unkown W&B. I have seen to many of them that has been wrong, both in mass and distance and therefore in CG, even the original factory W&B can not be trusted as it sometimes is pre-made prior to finishing of the glider.
Do it your self properly once. Any change in instruments, ballast, trim weights, etc can later on be calculated.

/Per

[Skytime]

On Saturday, October 24, 2015 at 10:13:06 AM UTC-5, JS wrote:
> Perhaps download this manual in English, and look at page 46.
> Jim
>
> http://www.williamssoaring.com/fleet/ASK21_manual.pdf

Thanks.

I found these pages from the manual which are much clearer and, easy to print graph.

http://www.alexander-schleicher.de/wp-content/uploads/2015/03/210_TM35_US_HB.pdf

[Skytime]

On Saturday, October 24, 2015 at 10:29:48 AM UTC-5, Matt Herron Jr. wrote:
> On Saturday, October 24, 2015 at 5:45:49 AM UTC-7, Skytime wrote:
> > Anyone have a simple wt. & bal calc method for ASK-21? The manual is all in German and makes no sense. Power-plane manuals are simple to use with a graph.
>
> May I shamelessly recommend SeeG, a program specifically designed for C/G calculation on gliders, one seat or two. http://www.glideplan.com/styled-2/page12/index.html Simple, fast, and flexible.
>
> Matt Herron

Thanks. I stay with the paper math.

I would rather spend the $80 bucks on paying for a tow. :)

[JS]

Since this thread appeared, I contacted Matt Herron about phone apps. Getting the feeling it's not going to happen.
However, I downloaded the Appventive Weight + Balance app for Android and it works well. Will contact the developer with a couple of questions, primarily wanting to increase resolution an order of magnitude.
It's $10, and can be with you when you're adding a passenger, water ballast, etc. I move the fuel tanks, rename them and use weight as the input for water ballast.
Will also try Matt's SeeG program. The Jonker Sailplanes spreadsheet for the JS1 is the best I've used so far, wish all manufacturers had something like that to download. But spreadsheets aren't great on a smart phone.
Jim

[Casey Cox]

> I found these pages from the manual which are much clearer and, easy to print graph.
>
> http://www.alexander-schleicher.de/wp-content/uploads/2015/03/210_TM35_US_HB.pdf

Question for anyone:

How does one calculate or develop what I've seen called (Wedge), (Level Line), (Incidence Board)?
To ensure the fuselage is level, and in this case for the ASK-21 is 1000:52. And also in this case there is no reference of exact placement. Wouldn't it change the level if the board is more forward or more to the rear?

[[email protected]]

On Sunday, November 1, 2015 at 7:21:27 AM UTC-5, Casey Cox wrote:
> > I found these pages from the manual which are much clearer and, easy to print graph.
> >
> > http://www.alexander-schleicher.de/wp-content/uploads/2015/03/210_TM35_US_HB.pdf
>
> Question for anyone:
>
> How does one calculate or develop what I've seen called (Wedge), (Level Line), (Incidence Board)?
> To ensure the fuselage is level, and in this case for the ASK-21 is 1000:52. And also in this case there is no reference of exact placement. Wouldn't it change the level if the board is more forward or more to the rear?

If you generally follow the diagram it ends up on the straight taper of the tail boom which is pretty long and non critical.
Measure the length of your level, multiply by .052, and make a spacer that dimension.
QED
UH

[Casey Cox]

On Sunday, November 1, 2015 at 7:21:27 AM UTC-5, Casey Cox wrote:
> > I found these pages from the manual which are much clearer and, easy to print graph.
> >
> > http://www.alexander-schleicher.de/wp-content/uploads/2015/03/210_TM35_US_HB.pdf
>
> Question for anyone:
>
> How does one calculate or develop what I've seen called (Wedge), (Level Line), (Incidence Board)?
> To ensure the fuselage is level, and in this case for the ASK-21 is 1000:52. And also in this case there is no reference of exact placement. Wouldn't it change the level if the board is more forward or more to the rear?

Here is wording in another manual;
The horizontal reference line is the centre line of the fuselage tail cone or a 1000 : 45 wedge template levelled out on the top side of the fuselage aft portion

[Casey Cox]

> If you generally follow the diagram it ends up on the straight taper of the tail boom which is pretty long and non critical.
> Measure the length of your level, multiply by .052, and make a spacer that dimension.
> QED
> UH

Ok, thats sounds simple enough. I've never actually performed a W/B with an incidence board, but thought that the location would be more critical than you mentioned due to it seems fuselage booms taper slight at first and increases towards tail. Just a general observance though and never really measured or compared.

Thanks.

[GeneReinecke]

On Sunday, November 1, 2015 at 6:22:23 AM UTC-7, Casey Cox wrote:
> On Sunday, November 1, 2015 at 7:21:27 AM UTC-5, Casey Cox wrote:
> > > I found these pages from the manual which are much clearer and, easy to print graph.
> > >
> > > http://www.alexander-schleicher.de/wp-content/uploads/2015/03/210_TM35_US_HB.pdf
> >
> > Question for anyone:
> >
> > How does one calculate or develop what I've seen called (Wedge), (Level Line), (Incidence Board)?
> > To ensure the fuselage is level, and in this case for the ASK-21 is 1000:52. And also in this case there is no reference of exact placement. Wouldn't it change the level if the board is more forward or more to the rear?
>
> Here is wording in another manual;
> The horizontal reference line is the centre line of the fuselage tail cone or a 1000 : 45 wedge template levelled out on the top side of the fuselage aft portion

It is always easier to use a professional to weigh your glider. However, per my owner's manual, I did the math (1000:45/2) on a 50" piece of 2 x 4, cut the smaller piece (approx. 2.25 in) and duct taped it at a right angle. I then took the glider and my assy to our local A&P. He had a fancy digital incidence scale in addition to good aircraft weight scales. Although we went with his methodology, I was happy to see me homemade incidence taper was dead on. Design with a supercomputer, measure with a micrometer, cut with a sawzall...
Cheers
Gene

[Dan Marotta]

Or, as we said in the Air Farce: Measure with a micrometer, mark with a
grease pencil, cut with an axe. I don't think we had supercomputers
back then...

On 11/1/2015 7:35 AM, GeneReinecke wrote:
> On Sunday, November 1, 2015 at 6:22:23 AM UTC-7, Casey Cox wrote:
>> On Sunday, November 1, 2015 at 7:21:27 AM UTC-5, Casey Cox wrote:
>>>> I found these pages from the manual which are much clearer and, easy to print graph.
>>>>
>>>> http://www.alexander-schleicher.de/wp-content/uploads/2015/03/210_TM35_US_HB.pdf
>>> Question for anyone:
>>>
>>> How does one calculate or develop what I've seen called (Wedge), (Level Line), (Incidence Board)?
>>> To ensure the fuselage is level, and in this case for the ASK-21 is 1000:52. And also in this case there is no reference of exact placement. Wouldn't it change the level if the board is more forward or more to the rear?
>> Here is wording in another manual;
>> The horizontal reference line is the centre line of the fuselage tail cone or a 1000 : 45 wedge template levelled out on the top side of the fuselage aft portion
> It is always easier to use a professional to weigh your glider. However, per my owner's manual, I did the math (1000:45/2) on a 50" piece of 2 x 4, cut the smaller piece (approx. 2.25 in) and duct taped it at a right angle. I then took the glider and my assy to our local A&P. He had a fancy digital incidence scale in addition to good aircraft weight scales. Although we went with his methodology, I was happy to see me homemade incidence taper was dead on. Design with a supercomputer, measure with a micrometer, cut with a sawzall...
> Cheers
> Gene

--
Dan, 5J

[Casey Cox]

I just found one specific glider manual stating 1000:40 with 300 mm in front of vertical stabilizer. Either it makes some difference in this specific glider or the manufacture is more precise.

Casey