PDA

View Full Version : Discussion HQ-3.14 Strak?

balsabozo
Apr 17, 2009, 10:58 AM
Anyone have any experience with the HQ-3.14 Strak airfoil?
I am considering a plane with it but going in blind and want some more info.
Bernd Brunner
Apr 17, 2009, 12:38 PM
HQ 3/14 is an airfoil from Helmut Quabeck with 3% camber and 14% thickness. Normally used for big scale ships. Itīs a high lift airfoil.

Bernd
balsabozo
Apr 20, 2009, 11:24 AM
so meaning some under camber, more floaty character?
Bernd Brunner
Apr 20, 2009, 12:32 PM
not really floaty... the HQW 3/14 is used as root airfoil, when you need the thickness for the spar. For most of the wing then the HQW 3/12 will be used.
This airfoil is very good for Re number > 200000. Large scale ships are relatively heavy, which means they have high wing loading - at least twice compared with TD ships. The usage of flaps is highly recommended. Many scale ships here in germany are using the HQ 3/14 as root airfoil - itīs very common.

http://www.hq-modellflug.de/hqw-3-12-polaren.htm

Whatīs the reason for your question?

Cheers,
Bernd
balsabozo
Apr 20, 2009, 01:23 PM
there is a dg303 acro 4m scale from airworld, germany that uses this foil.

http://www.airworld.online.de/Englisch/Segelflugzeuge/DG300/index.htm

i would like to use for primarily flatfield, aerotow thermal seeking perhaps even alpine soaring and upandgo installation.

apparently they are willing to install flaps as i would like to have full span camber/reflex capabilities.
Bernd Brunner
Apr 20, 2009, 01:36 PM
IMO the description is ok. For pure thermal seeking the extended wingtips will be necessary. Let them install bottom hinged flaps. Itīs much better if you want to use them for landing (crow).

Bernd
target
Apr 20, 2009, 08:20 PM
Bernd-

Please answer this question for me:

What does "Strak" mean in english??
Does it mean "Modified", or "Transitioning", or something else??

Thanks in advance!

Target
paul dufek
May 03, 2009, 12:14 AM
It means to stretch or lengthen.
target
May 03, 2009, 12:21 AM
Thank you, Paul! That has been a mystery to me for quite some time.

Regards,
Target
Bernd Brunner
May 03, 2009, 09:04 AM
No, "strak" means transitioning different airfoils along the wing span.
The simplest Strak is e.g. a HQ 3/14 at thr wingroot and a Naca0009 at tip.

Bernd
target
May 03, 2009, 10:18 AM
Thanks, Bernd. You are the German man, I believe you.

Target