PostFrontal Forum
PostFrontal Forum
LK8000_Support_Forum | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password
Forgot your Password?

 All Forums
 LK8000 International Support
 General Support
 DG1001 18m POLAR REQUEST
 New Topic  Reply to Topic
Author Previous Topic Topic Next Topic  

freewing70
Pterodattilo

Italy
1268 Posts

Posted - 25/08/2014 :  22:50:24  Show Profile  Visit freewing70's Homepage  Reply with Quote
Hello experts,

Could anyone give me the datas to build the DG1001 18m (not 20m) polar?
It's missing from the huge gliders list of LK, and I often get requests from local pilots (we have a DG1001 in our aeroclub).

Requested infos are for 2 pilots (PAS+PIL config):
MassDryGross[kg], 603???
MaxWaterBallast[liters], 160
Speed1[km/h], 106
Sink1[m/s], -0.7???
Speed2, 153???
Sink2, ???
Speed3, 200???
Sink3, ???
WingArea[m2], 16,72

Here's the polar
http://www.dg-flugzeugbau.de/Data/dg-1000-polare2.jpg

Thanks a lot
Enrico

- enrico


Edited by - freewing70 on 25/08/2014 22:57:07

Marco from Hangar 5
Pterodattilo

Netherlands
886 Posts

Posted - 27/08/2014 :  00:01:21  Show Profile  Reply with Quote
Uhm, the attached polar is of a DG1000, so probably the DG1001 does not have a much different polar.. just use the DG1000 polar that is present in LK80000.. well, that is what I would do.

But if you have the correct polar for your aircraft (should be included in the flight manual) you can make a polar file yourself, see the full manual of LK8000 version 3.0 paragraph "27.2 LK8000 polar file"

If you do not have the correct polar file, maybe it is included in the SeeYou mobile application, you can download an unregistered version from the Naviter website and check if the polar is present in SYM, if so you can use the values of that polar to make your own LK8000 polar file. I have done the same for my Mini Nimbus and worked very well for me, the Mini Nimbuis polar file I made is now standard present in LK8000 :)

Important is that for the weight you fill in the polar file, you take the weight WITHOUT water balast, in case of the DG1000 the wingload is given, 28Kg/m^2, so multiply this with the wing area and you have the weight that was used for that polar (MassDryGross)

For the speed pairs, on the horizontal axis you can read the indicated airspeed, on the vertical axis the sink speed.. In case of the DG1000 for example, 100km/u you have 0.6m/s sink

Success!


Marco
BU (PH-588)
Mini Nimbus HS7, s/n 039
http://www.zweef.nl/
Zweefvliegcentrum Noordkop, NETHERLANDS

Edited by - Marco from Hangar 5 on 27/08/2014 00:22:15
Go to Top of Page

AlphaLima
Moderator

Germany
1978 Posts

Posted - 27/08/2014 :  21:27:37  Show Profile  Visit AlphaLima's Homepage  Reply with Quote
Marco,
he is aware how to build a polar. He is searching for a DG1000 18m polar data.

Edited by - AlphaLima on 27/08/2014 21:55:06
Go to Top of Page

freewing70
Pterodattilo

Italy
1268 Posts

Posted - 27/08/2014 :  23:43:02  Show Profile  Visit freewing70's Homepage  Reply with Quote
Thanks to all.

I had some provate answers, so maybe I'll submit "my polar" fot that glider to get more feedback from you.
WL = 603/16,72=36.07; I guess I can use the "middle polar" of the linked graph.
What I need to check is the fact that DG1001 18 m doesn't seem to have ballast at all; may I set that value to 0?

THX AGAIN

- enrico

Go to Top of Page

Marco from Hangar 5
Pterodattilo

Netherlands
886 Posts

Posted - 28/08/2014 :  16:59:17  Show Profile  Reply with Quote
Hi,

If you have nothing else, using the middle polar is the best option, yes.. But realize it is still not 100%, because it does not take into account the CL/CD changes because the wing surface has decreased. Probably you should move the polar somewhat down as the maximum glide ratio (CL/CD) is a bit worse then the 20m version. If you know the max glide ratio, you could draw a new line and move it down to that line.

Another way to cope with the deviations is to set the efficiency a bit lower then you used to (in LK8000>Menu>Config 2/3>LK800 Setup>System setup> Page 6 Safety Fctors). Normally I set this value to 95%, to compensate for my unintended side slipping, but you could set it 5% lower to compensate for the not so optimal polar that is used, so in my case I would set it to 90%.

But best would be if DG provides the right polar for the DG1001 18m

Marco
BU (PH-588)
Mini Nimbus HS7, s/n 039
http://www.zweef.nl/
Zweefvliegcentrum Noordkop, NETHERLANDS
Go to Top of Page

freewing70
Pterodattilo

Italy
1268 Posts

Posted - 30/08/2014 :  23:38:11  Show Profile  Visit freewing70's Homepage  Reply with Quote
Thanks Marco,

I'm taking as useful words what you write.
BTW, after some tests in Aosta we - "normal" pilots, not champs - use to set 64% the efficiency (for mountain flight).

Thx again

- enrico

Go to Top of Page

freewing70
Pterodattilo

Italy
1268 Posts

Posted - 04/09/2014 :  12:26:15  Show Profile  Visit freewing70's Homepage  Reply with Quote
That's "a polar"... take it as it is.
We just built it for our pourpose (that means: use it at your own risk).

http://www.aecaosta.it/LK8000/DG1001_18MPAS.zip

- enrico


Edited by - freewing70 on 04/09/2014 12:26:43
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
Jump To:
PostFrontal Forum © PostFrontal - La community del Volo a Vela Go To Top Of Page
This page was generated in 0.14 seconds. Snitz Forums 2000

Since 2006, owned and maintained by PostFrontal S.A.S. di Giuliano Golfieri & c. - VAT ID: IT05264240960
THIS WEBSITE ONLY USES FUNCTIONAL COOKIES
Privacy & Cookie Policy