|
1.Models
|
2.Tips and technic
a windy experience... Dowloads
(JC Etiemble)
 Tracfoil : to
plot every airfoils !
|
|
3.Aerodynamics / Flight mechanic
|
4.Miscellaneous
vocabulary. |
You are my
XXX
th visitor, thanks !!
since 13th may 2000, when the counter last broke...
I am a student, then there is still
some articles for french reader only, excuse me...
Flying wings.
F3i : towed
sailplanes
F3i is a FAI rule for sailplanes with
span larger than 3500mm, that uses aerotowing to start. It is a "speed
- duration" event.
For me it's a project at school, too.
Scale
sailplanes.
Come to discover scale sailplanes !
Electric flying.
Hang and cliff gliding.
I am from Normandy in France, and this countryside is not famous for its sun and nice wether. Whereas there is nice cliffs here, that are really flyable !
HLG
I had already built a Slider and a
personnal model(Mostiko, plan encarté RCM n°190).
here is a large HLG,
for calm days at the slope.
It is here displayed ready to fly.
It can really fly into small and weak thermals, but it is quite lazy to
handle !
For checking the accuracy of my Excel polar calculator, I computed polar and L/D ratio according to speed for this HLG, with S4083 airfoil. It is quite realistic, even if a little bit optimistic.
Kite towing : a windy
experience...
Have you ever tow a glider with
a kite ?
When two hobbies join together, you can
do interesting things.
The
"débattomètre"
This untranslatable term hides a simple device which will allow you to trim your sailplanes more easily.
The soft
"Mean Aerodynamic Chord"
Programmed by Jean-Claude Etiemble, this
small soft will make your modelers life easier.
It computes for you the mean aerodynamic chord and the CG for wing with
up to 5 panels !
Both in metric and non-metric system.
Tracfoil, a
genuine airfoil plotter
The state of the art, by Jean-Claude
Etiemble !
This soft plots every *.dat airfoil, and
draws spar, leading edge and other features on the ribs.
It also plots template for foam cutting. It worths at least
"compufoil", but it is far cheaper !
NEW : buy tracfoil license online to
its author !
MIAReX, a program for
multi-airfoil wing calculation
Here is a very useful and interesting program, that compute polar for multi-airfoil wing. The calculation method used is based on lifting line theory, généralised to non linear behaviour of airfoil section.
Flight dynamics :
eigen modes location.
AVL from Harold Youngreen & Mark Drela is an
aerodynamic (VLM) tool, but it also computes rigid eigen mode of a
glider.
A pair of models of glider were evaluated through this tools, allowing
to get some knowledge about what can be hoped, eigen mode speaking, for
a sailplane model.
| Here are some commented examples : |
Aerodynamic tuning of
a Nimbus 4D model.
I got my Nimbus as a second
owner, but I was really disappointed not to fly and trim it
properly at the first place.
I did some deep investigation, that leads
to some aerodynamic improvement.
this was successful since now it flies much better !
Low Reynolds
airfoil polars
Xfoil is a code that allows calculation
with viscosity effects. Then the
polars are quite accurate for models aifoils.
Here are some result for different Re
number.
| Airfoil | Use |
| MS1,9/8,7i | f3i, f3b, f3f with flaps |
| MS2/9,5i | f3i, f3b, f3f with flaps |
| MS3,3/15GP | Scale sailplane (root) |
| MS3,3/11GP | Scale sailplane |
| MS3,3/11GPT | Scale sailplane (tip) |
Olivier Bordes also plots some polars, for F3F airfoils.
Speed flight : F3i,
F3b or F3f. I made some calculation about
speed flight in glider event. At first according to energetical ideas,
but it
did not fit really well. And then I studied Helmu Quabeck's book : "Design,
Leistung und Dynamic von Segelflugmodellen".
I took his ideas for the calculation, and I add some personnals ideas
too.
It seems to give pretty close accurate
results, at least for F3i.
This is summed up into an excel sheet (in
french curently). Some parameters are taken into accompt :
As usually, there are some restriction to calculation.
Hopefully those choosen are quite
accurate, but don't forget to keep CRITICAL in front of strange result.
Understanding "dynamic
soaring". DSing is quite widespread
today. It is an extraordiar way to fly faster and faster. It is even
quite magique, and I wanted to know from where all this energy comes.
So I made an excel sheet (once again...)
to compute this, and to understand
what are the main parameters for DSing. I had to make some
simplification, but you can have an idea
of the ideal path according to the glider and the wind.
Main hypothesys are :
Miscellaneous
calculation. Here at SUPAERO school, I am
taught to
calculate many things on plane. So I
apply this to all what worries me, and I make some excel sheets.
You have to keep aware that all those calculations have an "area of
accuracy". Don't forget to read instructions.
Here are some adresses displying free CFD
code :
A short
3-language gliding terms vocabulary Rather than a genuine dictionary, here is displayed a short vocabulary. Terms are given from english, to french and german, according to different topics.
Links.
Some pages I surf on... Let me know wether they interest you as much as me ...
