Herewith my FLZ Vortex version of the Le Fish VTPR Glider with a modified TP28-4.

After a longer quest to solve Curvature Reversals, Spikes, Bumps trailing edge Artefacts and "Lift coefficient for shockless inflow" reducing repaneling, I hopefully now have a method that addresses most of these issues to my liking.

Repaneling is done with 601 Interpolated coordinates along a spline curve. Two Programs do this without reducing the Lift coefficient for shockless inflow and actually increase it, Profile 2008 and JavaFoil. Profile2008 adds the 0,0 coordinate and its Standard coordinates have a defined x coordinate distribution which is the same for the top and bottom which also helps when modifying the coordinates later.

Then the long process of editing the 201 (196, 5 coordinates are not moved) redistributed coordinates in Profileditor begins.
The Spikes are the easiest to remove by looking at the Velocity distribution, initially in Alfa 0,5 steps. The leading edge is easy and is described well in the "Editor Beispiel" help. The trailing edge which seems to have been neglected in the past has allot of performance hidden in the last 90 percent and is suitablly difficult .
Maybe due to cterat in Xfoil ?,
...Continue Reading

Since the download to this useful Program does not seem to be available and the Author encourages sharing I am posting it here.
I generally set the Wing Incidence to the Airfoils "alpha_s - angle of attack for shockless inflow" as I use the Airfoils "Cl_s - Lift coefficient for shockless inflow" as a control metric in Profileditor if I am improving the Airfoil or not. A simple repaneling of the Airfoil changes this value. "alpha_s" can be input into Schwerpunkt 52 and corresponds with its calculations.

German Translation below:

Calculate the center of gravity and setting angle difference

0. General

The lift that a model aircraft needs to fly is a direct function of the flight speed and the lift coefficient of the airfoil used, the latter again depending on the attitude angle difference (EWD). It then looks like this:
If the lift is always assumed to be the same, the model needs a larger lift coefficient to fly slowly, which is achieved by a large EWD of, for example, 4°. If I want the model to fly faster, I add depth control or trim lower and thereby reduce the EWD, for example to 0.5°, which means a smaller lift coefficient.

For a specific EWD and the desired flight condition, the model must be balanced, i.e. the center of gravity depends on the EWD. With a large EWD we need a center of gravity further forward than with a small EWD. The position of the overall neutral point of the model depends on the size of the horizontal...Continue Reading

I decided to enter Mike Seale excellent Orcrist 2.5m design into FLZ-Vortex and try the design with TP66 airfoils.
I spent allot of effort repaneling the airfoils to a standard 201 coordinates withoud loosing the airfoils lift and then set the wing to my now standard angle of attack for shockless inflow. The Wing dihedral should allow for a straight joiner tube and is based on the airfoils positive zero lift angle. For foam cutting the wing is split into two 600mm panels with the airfoil generated as a "Strakprofil, absolute Eingabe" that creates a nice washout for the wing. The wing and stabilizer have a 1mm thick trailing edge.
The fuselage is set at its zero lift angle and allows for a mad stab with its 16mm thick fin.

VTPR, or “Voltige Très Près du Relief” in French and “aerobatics very close to the ground” translated in English.
enjoy

Herewith my FLZ-Vortex redesign of this old classic with modern software tools for further optimization and probably better performance.
I started off with a manually corrected R_23012 which I then thickened to a 23014 for the root airfoil. I decided against using a 15% airfoil at the wingtip and instead used the R_23012 . For the interpolated airfoil between the root and tip I created an "absoluter Strak". All the airfoils have a 1mm thick trailing edge according to the chord and both the wing panels sweep is a straight line at 50% for easier spar construction. The first panels sweep at 25% is 0 degrees.
These airfoils where then all handed over to jxjo's excellent AirfoilEditor for the Bezier treatment with healthy leading edge radii which is necessary after opening the trailing edge and some smoothing from Xoptfoil-JX.

Once the original design was input as accurately as possible into FLZ-Vortex and Schwerpunkt522 it was found to be too generous in the tail moment and for the ritz airfoil too generous in the area of the horizontal stabilizer to come anywhere close to the airfoils optimal angle of incidence (EWD).

After the required adjustments the the wing was set to the airfoils alpha_s angle and the design "flew" better than before.
FLZ-Vortex still notices the airfoils laminar separation bubble however I have not figured out how to modify the airfoil to solve for this, possibly too thick ? The Polar's in xflr5 are very clean.

Enjoy

This is my FLZ-Vortex version of the awesome Madslide plans. I returned to the Venkataraman airfoil fit for the airfoil as this was giving me the best Lift improvements and the nicest laminar airflow over the airfoil. It would be interesting comparing the smoother version of the airfoil with the original 4 decimal experiences.
The wing Root and Tip airfoils where opened up for a constant 1mm trailing edge, and the tail surfaces are all 5mm flat plate.

After reading up and testing John Hazel's wing LIFTROLL design tool, I have come to the conclusion that FLZ-Vortex is able to more accurately model the Lift Distribution (with more vortexes, panels ?) and that the Fibonacci Sequence helps to generate nice looking wing segment widths.

After some testing I will however not be using alpha-0 zero lift angle for the washout in the wing as I have found the airfoils alpha_s angle of attack for shockless inflow to give better results for washout with the entire wing operating at Cl_s Lift coefficient for shockless inflow. The Wing root incidence is the root airfoils alpha_s angle and the washout is the difference if positive of the tip airfoils alpha_s angle.

The Wing Dihedral angle set to positive the airfoils zero lift angle does provide interesting results. The Fuselage is set to its negative zero lift angle. An improvement with this setup may be to raise the Stabilizer as it is in the wings wake turbulence although this could also just be something the Vortex cannot calculate.

The screenshot from the Program Schwerpunkt und EWD shows the 3 different methods for calculating the CG and usually corresponds with the results from FLZ-Vortex. I usually use it to sort out the tail moment and the Cl operating range.


enjoy

Herewith my latest FLZ-VORTEX design with JX-GT RE*Sqrt(cl) optimized Airfoils.

The initial Wing planform was found on the Thermik Board Forum and adjusted for a 0 degree sweep angle at 75% and no decimal millimeters. Also the leading edge sweep angle at the tips should not exceed 45 degrees.
I then calculated the RE*Sqrt(cl) for the root and tip airfoils and selected the appropriate JX-GT Airfoils. I re-paneled the Airfoils in Profileditor first to 401 coordinates Sin vorne, manually adjusted the first coordinate to be at 0,0 0,0, checked the trailing edge coordinates to be at 1,0 0,000150 top and bottom and then rotated and normalized with Trailing Edge Extrapolation X=1 !. The last step is important when re-paneling the airfoil from 7 decimals down to 6 as the coordinates on the X-Horizontal Axis need to be corrected. With Planform Creator 2 this is usually only 0,000001 however when I used Interpolate Foils in Xflr5 I was seeing up to 0,000005 difference in random places when comparing Airfoils in WinMerge.
The Root airfoils where then thickened to compensate for the 1mm te thickness of the Tip airfoils. This step is done in Profileditor as it opens the airfoils te to the mm exact for 6 decimals, the airfoils are thickened in Sielemann Profile as this works with uniform x coordinates.
The airfoils where then re-paneled again down to 201 Cos rotated and normalized and the curvature adjusted, especially at the le at Angle of Attack 4 degrees and above. With...Continue Reading

Herewith my FLZ-vortex version of Mark Drela design.

I started off by recreating the wing planform from the dxf plans which resulted in a Planform with a straight LE out to 50% and a straight TE to 90% with twelve ribs or segments.

For the wing airfoil I generated a strak of the AG 04 to the AG10 after I had edited the TE of the airfoils. I could not get the blended airfoils to work the way I wanted.
The TE of all the strak airfoils where thickened to 1mm at their respected stations and the coordinates have parallel horizontal stations top and bottom as I was not able to distribute the coordinates without them undercutting the neighbouring airfoil especially in the LE.

The top and bottom curves of the airfoils where created in BezierAirfoilDesigner which has proven itself again in creating excellent curvature that is very stable even with 6 decimal places.

The HT12 V-tail airfoil was opened up to 1 mm at the tip and the root was thickened to have the same thickness. The resulting strak looks good.
The squat fuselage pod was joined to a CARBON fibre tube (tapered/conical) 14.5x9x0.4x480.

enjoy

My FLZ-VORTEX version of this design adapted with jxjo's amazing PlanformCreator2.
The original airfoils once corrected, the NM10 bottom curve rotated to center the te, were given to the BezierAirfoilDesigner to generate the bezier curves of the airfoils. The planforms were generated based on the data from the Predim RC files kipecoul released here.
The Wing was adjusted to fit and the V-tail had its area and tail moment increased as I was having stability issues in my analysis. To generate an Airfoil Strak I added the original Airfoils at the wing tips with a thickened te to 1mm as these were already very thin and then thickened the root airfoils with the 1mm te to be as thick as the tip and the high point moved back to be slightly behind that of the tip. The Airfoil Editor did this perfectly !

The amazing thing about this small modification is that the Cl/Cd max between the root = 25.7 and tip = 32.5 at the same Re, which I think is good but may need further investigating.

The design fly's nicely in FLZ, maybe a bit fast and the Airfoil is receptive to flaps, see the screenshots with the flaperon at +3 degrees.

I'd be interested in hearing from anyone that has more time than me and wishes to build one.
enjoy.

My redesign of this Hartmut Siegmann Design in FLZ Vortex with allot of help from the excellent tools from jxjo. Many Thanks to Jochen for all his work and the education !

I first ran the example from Xoptfoil-JX to create the tip MH32 Airfoil. This was fed with my modified mh32-A with 201 coordinates and compared with the originally provided 68 coordinate Airfoil.
Following this I added the root and tip Airfoils to the PlanformCreator2 and adjusted my original FLZ Trapezoid planform for the Wing and the V-tail to closer match the Bezier curve. The Bezier function is very good and in future I think I will go for the complete Bezier curve. I think one can see the reason why the Bezier curve is better when I look at the airfoils in their 'real' scale within their wing sections.
I then created all the strak airfoils with a constant 1mm te gap in PlanformCreator2 which is a massive time saver.

enjoy

I decided to rebuild the Shen-Ven from the last plan I still had with me from my Workshop many years ago. On further research I found that Outerzone also had archived a digital version of the plan.

My new version was designed with a S 3021 airfoil with one coordinate on the bottom near the trailing edge modified to make it perfectly flat, since we are now cutting out the ribs with CNC. .
The TE is opened up around 0 to 1,6 mm for the 1/32 sheeting. The ribs where all interpolated in Sielemann Profile as I have found his Standard Coordinate system to be very good. Standard coordinates are profile coordinates with a defined distribution in the X direction. If the X-values on the top and bottom of the source profile are not opposite each other (e.g. Eppler profiles), then the source coordinates are automatically converted to standard coordinates. Format X 100 --> 0 --> 100 .

The Rudder and Dihedral where calculated with Sailplane Calc Cruciform Tail Metric May 2016 from Tailwind Gliders and adjusted according to Recommendations.

My next step is to generate the CNC files from the DXF exported from FLZ-Vortex, which all takes a bit longer than cutting with a knife and ruler .

enjoy

I used Marko Stamenovic's Excell file to design this nice looking Horten Wing for 3d Printing.
The Airfoils are opened to a 1mm trailing edge and the Root airfoil is thickened to generate a bit of a fuselage.
The Root and Tip airfoil was created in Marko's also brilliant Horten Airfoil Designer .exe which produces very clean airfoils, and the rest done in XFLR5.
The results from the Excell file work out exactly as advertised in FLZ. I am not sure why one would want to use other values.

Aspect Ratio 10
Taper 0.5
Sweep LE [deg] 20

A little explanation of methods used:

- Twist is calculated using Prandtl's Lifting Line
Theory. Read top comments for more details
about limitations.

- Panknin formula was used to calculate trim Cl.
It is simple approximation that has been used
in RC world for some time. Calculations are done for basic trapezoidal planform.

- Usually, BSLD is designed for trimmed Cl but since
BSLD should be designed for Cl between 0.4 and 0.6 (in order to avoid tip stall first) if you want trim Cl (without elevon deflections) to be lower than 0.4 then it becomes impractical to use common approach. That is the reason why I choose to make calculations the way they are.

- If you want trim Cl to be in the range between 0.4
and 0.6 you still can tweak SM and Cm0 of airfoils so trimmed Cl is the same as Cl for BSLD.

The initial 3d test print scaled to 180mm wing half came out awesome.
The main Spar is 5mm plugged into 7mm Carbon fibre tube and the sub Spar 3mm into 4mm. The sub spar is in front of the elevons , the main spar at 25%.
Dxf is exported from FLZ.

My latest simulation in FLZ Vortex with a modified TP202-9% Airfoil with TNT wingtips.
The trailing edge was thickened to 1mm for foam cutting which came out really well with a new method in Profileditor, less drag. The new repaneling methods leading to nice velocity distributions on all Profiles.

enjoy

Hi,

herewith a 1,260 m Power Slope Scale design in FLZ_Vortex. It is based on a Prototype Me 209 1943 with a smooth Bf109 fuselage for Reno racing .

The airfoil is a thinned original Bf109 NACA 2R1 11.35 airfoil that went through allot of editing in Profileditor and repaneling in jxjo's Planform Creator 2 Airfoil Editor.

The end result is what I gather from the comparison to the eppler-374 in xflr5 an airfoil that performs better at lower Reynolds numbers.
Id love to hear if this is confirmed in practice

enjoy

My latest design, a 1,680m Aerobatic Slope Soarer in FLZ Vortex and Profile Editor.
It is inspired by the Phase 6 which was my first slope soarer, is called the iNgede and comes with P28-4 near symmetrical Airfoil (0.9% camber) designed for “voltige totale” in light conditions.

I tested various smoothing methods on the Airfoil and after some correcting due to the missing 7th decimal in the coordinates it came out fine. I keep on coming back to Profile Editor with manual editing as the best method to edit coordinates.
The trailing edge is opened at 0,0 to a constant 1mm for structural reasons and the tip Airfoil is thinned by 0,5% to compensate for this.

The Wing is set at the Airfoils alpha_s (angle of incidence) and the Fuselage at its alpha-0 zero lift angle. For the Wing dihedral I tried something new by making it half the wing Airfoils alpha-0, which I think came out interesting

enjoy

Here is my second attempt at a Rivington Hawk inspired PSS Glider. This time the long nosed Hawk 120 and hopefully improved Aerodynamics simulated in FLZ_Vortex. I took allot of tips from aerodesign.de design studies on Nurflügel.

The model is still in the old FLZ version but opens and simulates just fine in the new version, which also has some nice new tools which I am still getting to know.

enjoy

Herewith my latest Slopie "Magpie" for Slope Pylon Racing simulated in FLZ_Vortex.

I ended up testing two separate airfoils both based on the RG 15 one faster and the other for lighter lift. The faster one NG15_100k airfoil interestingly has similar performance simulated as the MU 8.5/1.73 airfoil (modified trailing edge) with +2 degrees of flap.
When changing the airfoils in FLZ_Vortex remember to change the Angle of Incidence of the wing to the angle of attack for shockless inflow of the airfoil.

The trailing edge gap of the airfoils is a constant 1mm to enable foam cutting, enjoy

Model building with Software tools rather than trial and error Aerodynamics is almost as much fun as flying , a big thank you to the Software developers for all these great tools ! .

Here is my version of the Carrera Sagitta with the modified Bf 109 Profile. The .zip file contains the FLZ Vortex file for simulation, all Profile coordinates with a 0,4 mm constant trailing edge and the exported DXF file for possible construction.

It was interesting looking at the original 109 Factory Airfoil coordinates and how modern software coordinates compare to them. From the factory blueprints the F through to K wing supposedly uses a 2R1 14.2 profile at the root, a 2R1 12.9 profile at rib 9 (60.5% along the wing), and a 2R1 11.35 profile at the tip. Compared with the modern NACA 2R112.

A FLZ version of this glider which I started from a WIK design which after finding factory drawings turned out to be very scale.
The original Eppler e195 was compared and replaced with the with the NM 32, a profile intended to improve the performance of the famous HQ profiles which are legion on large flap or non-flap gliders. This profile may be a little thick for this scale especially at the tip where the original had a 9% e174. Scaling the design up to 1-4 should be relatively easy in FLZ-Vortex.

Inspired by a French design in Model Magazine with an updated Wing Planform and Airfoil. The Pod and Boom fuselage came out really well, and the modern Clark Y "Strak" looks good in XFLR5.

This time a VEB Cirrus from 1974 with updated wing geometry, Ailerons and profiled Empennage.
The original e374 was replaced after some comparison on BigFoils Similarly shaped airfoils and in XFLR5 with the SB98 VR-S5 series. The Venkataraman airfoil fit producing the final smooth airfoils.
With any luck it might make for a nice VTPR Glider when built.