Extasy - Introduction

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• Designer 2011
• Designer 2010
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Extasy - Details

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Extasy - Settings

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Extasy - Mounting

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Extasy - Performance analysis

• Introduction
• Details
• Performance analysis
• Settings
• Mounting
• Designer 2011
• Designer 2010
• Pictures
• Prices

• Summary results
• Detail model performance
• Compare Extasy and Evolution characteristics
• Visualisation

At the beginning...

Our first experience with the XFLR 5 program was with the previous F3B model Evolution. When we designed the new model Extasy, we used our experience with this program again. The program can be used for determining the center of gravity and the angle difference between wing and elevator. Besides now we can compare the design of Evolution and Extasy in XFLR 5 and see the differences of both models in flight characteristics.

The Extasy was originally developed by Günter Aichholzer and airfoil by Maximilian Steidle as a faster version of the Evolution for better results in F3B tasks speed and distance. To achieve that the (aoa) angle of attack of the wing and angle between aoa wing and aoa elevator (v-tail) is very important. The value of the wing aoa is usually set from 1,5 degree (for more thermic-slower models) to 0,5 degree (faster-slope model). When the wing aoa is selected, then we must be find out the elevator aoa. The value of this angle depends on many conditions. There are two ways to find out this value. First way is method of trial and error, manufacturer tests model with many different values of elevator aoa. When the correct value is found, it is used on the final model. This may take some time and the result is unknown. Sometimes it is better to start at the beginning with a new value of wing aoa. Second way is to simulate flight characteristics before the model is even created. This gives us the opportunity to test many diferent configurations and select the right one to realize.

Extasy perspective view in XFLR5	Extasy back view in XFLR5	Extasy left view in XFLR5	Extasy top view in XFLR5

Summary results

When the model Evolution was made, we did not know about the program for the analysis of flight characteristics - XFLR5. Later we found this program and recreated the model Evolution in it. It turned out that the calculated flying properties of the model were very close to reality. In particular, the speed at which the model flies when control surfaces are neutral. To accelerate the model Evolution (for task distance and speed) it was necessary to push the elevator down by 0.6 mm. This property is also confirmed in the simulated model XFLR5. The new model Extasy was designed to avoid the need to suppress the elevator for a faster flight. With this the model achieves better performance in tasks of speed and distance. Velocity of the Extasy with control surfaces in neutral position was determined by the Evolution with suppressed elevator, which is about 16-18 m/s. The real Extasy model showed that indeed it is no longer needed to push down the elevator.

The terms used below

The program also revealed the flow interference between the wing and elevator. This interference causes the unusual behavior of the model at high angles of attack. When normal models lose speed and become non-steerable. Extasy on the contrary, shows to be very stable even at high angles of attack of the wing, such as in thermals. This table shows the percentual changes in flight performance of different model weights, according to the following graphs.

Extasy - summary of flight characteristics
model weight [g]	stall speed [%]	minimum descent		maximum glide ratio		trim speed [%]
		speed [%]	descent rate [%]	speed [%]	glide ratio [%]
2050	100	100	100	100	100	100
2400	107,3	107,4	105,0	109,5	104,1	109,4
2800	115,9	117,0	112,5	119,0	107,8	118,1
3000	120,7	122,3	115,0	125,7	109,0	122,0
3200	125,6	125,5	117,5	133,3	111,4	126,0
3400	128,0	129,8	120,0	141,0	113,5	130,7

Detail model performance

The results of the calculations are not verified by measurements on the model. All graphs shown here are based on the calculations by XFLR 5, which does not take all influences on the model into account. This is important when working with this information, the absolute values will not be as in reality. More useful information is provided by the graphs when the individual parameters at different model weights are compared.

Descent rate

The following charts show the relationship between model speed and model descent rate for different weight of model. This applies for direct flight, in turn on base are present further losses, which increase descent rate. It shows, for task speed, more model weight means a better result.

Full scale velocity	Low velocity	Medium velocity	High velocity

Forward speed

Speed relative to the surface (speed of model between bases on ground). Graphs show the relation between forward speed (Vx) and descent speed of the model (Vz). Increase model weight and decrease model descent speed. This applies for direct flight. Wind increases or decreases forward speed.

Forward speed at low velocity	Medium velocity	High velocity

Glide ratio

Is in simplicity the ratio between forward speed and descent speed of the model. Glide ratio is different for each flying speed of model and weight of model.

Full scale velocity	Low velocity	Medium velocity	High velocity

Trim speed

Trim speed - all control surfaces (elevator,aileron, flaps) are in neutral, then model has a stable speed where the curve intersects x-axis on graph. For Extasy interference wing-elevator causes trim speed graph is more complicated.

Simple trim speed graph	Interference wing-elevator affect glide ratio	Trim speed include interference wing-elevator

Compare Extasy and Evolution characteristics

glide ratio for Vx=8m/s to 20m/s	glide ratio for Vx=20m/s to 40m/s	glide ratio for Vx=40m/s to 65m/s	descent speed for Vx=8m/s to 16m/s

Visualisation (interference wing-elevator), drag distribution, lift distribution, pressure and stream lines

Drag distribution at 12,1 m/s	Lift distribution at 12,1 m/s	Stream lines visualisation at 11,2 m/s	Stream lines visualisation left view at 12,1 m/s
Drag distribution including wing-elevator interference at 12,1 m/s	Lift distribution including wing-elevator interference at 12,1 m/s	Stream lines visualisation including wing-elevator interference at 11,2 m/s	Stream lines visualisation left view including wing-elevator interference at 12,1 m/s
V-tail pressure distribution at 11,2 m/s	V-tail pressure distribution including wing-elevator interference at 11,2 m/s	Pressure distribution at 11,2 m/s	Pressure distribution including wing-elevator interference at 11,2 m/s
Stream lines visualisation in perspective view at 8,9 m/s	Pressure distribution at 50 m/s	Pressure distribution at 50 m/s left view	Pressure distribution at 50 m/s perspective view

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Extasy - Color design

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Extasy - Color design ver. 2010

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Extasy - Pictures

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• Designer 2011
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Extasy - Prices

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Pricelist, model versions and order

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