Board index Other Hangar talk Real aviation

Wind tunnel testing for students

The "real" thing.
Forum rules
Please refrain from discussing politics.

Wind tunnel testing for students

Postby curt » Sat Feb 24, 2018 10:03 pm

This week I had some fun supporting a class and several student groups running wind tunnel tests on a small RC model airplane. They were measuring lift, drag, and moments at various angles of attack, transforming the raw data into aircraft body coordinates, and the plotting the results. Pretty cool stuff. The coefficient of lift for this airplane peaks out at about 1.2. The wing continues to generate lift way past the stall point, but the drag builds up very rapidly as well. Photo credit: Curt Olson, used with permission. :-)

Image
Aerospace Engineering and Mechanics
University of Minnesota
curt
Administrator
 
Posts: 1168
Joined: Thu Jan 01, 1970 1:00 am
Location: Minneapolis, MN

Re: Wind tunnel testing for students

Postby Thorsten » Sun Feb 25, 2018 8:09 am

Hey, this is cool!
Thorsten
 
Posts: 12490
Joined: Mon Nov 02, 2009 9:33 am

Re: Wind tunnel testing for students

Postby D-ECHO » Sun Feb 25, 2018 8:18 am

wish there was some possibility to do this here ;)
Really cool :D
D-ECHO
 
Posts: 2459
Joined: Sat May 09, 2015 1:31 pm
Pronouns: Bea (she/her)
Version: next

Re: Wind tunnel testing for students

Postby Johan G » Sun Feb 25, 2018 4:46 pm

Building a wind tunnel is relatively easy. The main issue would be cost, getting meaningful measurements and calibration.

Wide section with a fan, tight section (with higher airspeed, but lower air pressure), and again a wider section. Could possibly be done with a fan, some cardboard, a [food preparation room] scale and some rods connecting the model to the scale.

Do a Google image search for "diy wind tunnel" or "scale model wind tunnel".
Low-level flying — It's all fun and games till someone looses an engine. (Paraphrased from a YouTube video)
Improving the Dassault Mirage F1 (Wiki, Forum, GitLab. Work in slow progress)
Some YouTube videos
Johan G
Moderator
 
Posts: 6629
Joined: Fri Aug 06, 2010 6:33 pm
Location: Sweden
Callsign: SE-JG
IRC name: Johan_G
Version: 2020.3.4
OS: Windows 10, 64 bit

Re: Wind tunnel testing for students

Postby curt » Sun Feb 25, 2018 4:57 pm

Our wind tunnel is driven by a WWII P-38 prop and a big electric motor. I think it can generate wind speeds up to around 100 mph. It recirculates the air and takes up 2/3rds of a pretty large room, but is surprisingly quiet. It is in the attic of what used to be the hangar. Back in the early days of my dept. (1930's) they actually designed, built, and worked on real aircraft. There are some cool pictures floating around that show the hangar with the Akerman tailless plane. Someday I want to build a scale model of that and fly it (perhaps autonomously.) It would be a fun and challenging project and would be a tip of the hat to our building's name sake, and his airplane that never really had a chance to fully fly. We have the original blue prints but I'm still trying to get a copy of them. Among other things, this is one of the reasons I started creating MAdesigner (madesigner.flightgear.org) ... as a tool to help design and build complicated wing structures based on logical (or higher level) design parameters.

https://www.aem.umn.edu/info/history/akerman.shtml

If anyone decides to build their own wind tunnel, *PLEASE* post pictures and tell us about your project. I think it would be very interesting.
Aerospace Engineering and Mechanics
University of Minnesota
curt
Administrator
 
Posts: 1168
Joined: Thu Jan 01, 1970 1:00 am
Location: Minneapolis, MN

Re: Wind tunnel testing for students

Postby danielHL » Sun Feb 25, 2018 5:32 pm

That looks really cool. I remember the experiments we ran in the lab when I was an engineering student. Our wind tunnel had an open measurement box of about 1m^3. Sadly we never measured airfoils or anything like it.

If I remember correctly the most expensive component is the six component force and moment balance you need. We got ours for free and someone built the rest of the tunnel. Fan, motor, gearbox, ducts - all pretty low tech. But big and veeeeery noisy :P
danielHL / D-FMPW
danielHL
 
Posts: 280
Joined: Fri May 02, 2014 7:23 pm
Callsign: D-FMPW
Version: next
OS: Linux


Return to Real aviation

Who is online

Users browsing this forum: No registered users and 1 guest