“New Coaxial-System Setup”

 

Unbelievable but it is 4 years ago since we have released a new coaxial-system or in other words: each year we could increase the propellers by 0.5 inch and from 18” to 20” propellers it is 11,11% more in diameter 😉

 

That you have a comparison how “huge/big” the new 20” propellers are, a short overview of surface from actual propellers:

- SG-GLAVAK 16”           105,60cm²

- Lantsov 16”                 123,36cm²

- SG-GLAVAK 18”           129,36cm²

- Ermolin 17,8”              137,27cm²

- SG-GLAVAK 20”           179,51cm²

+70,0% comparing to SG-GLAVAK 16”

+38,8% comparing to SG-GLVAK 18”

+33,6% comparing to Lantsov 16”

+30,8% comparing to Ermolin 17,8”

 

Following new coaxial-system configuration is now available:

@ SG CRE 03x V26-1S + 20” propellers (ultra-light)

- Total weight 14,6g

- F3P models up to 60g RTF

- 1s battery 120mAh

- Thrust 60g @ 0,9A and 3,6V

- Thrust 90g @ 1,4A and 3,6V

- Max. thrust 115g @ 2,0A and 3,6V

 

The new coaxial-system SG CRE 03x has couple of improvements compared to latest coaxial-system.
These allow us to run 20” propellers with high efficiency but still with same dimensions of actual coaxial-system SG CRE 02 or SG CRE 03.

The BL-motor has a special small pinion gear and new belt to realize a bigger gear ratio.

Further the 20” propellers has also a slight V-shape which has been proven already at the 18” propellers.

The coaxial-system configurations with 20” propellers are running with significant lower speed (rpm) which results in lower angular velocity.

The angular velocity has square influence at rotation energy.

Due to significant speed reduction the rotation energy of 20” propellers is lower which result in similar or even better behavior of model at figure “turn”.

 

In overall the new coaxial-system configuration has following advantages:

- more brake performance

- more constant flight speed during complete program

- more stable model behavior during flight out from downwards figures

- more stable in torque position due to V-shape design of 20” propellers

- more dynamic behavior in aileron due to wide air flow from 20” propellers

- fine throttle response and dosing

- very soft starting behavior (very low idle speed possible)

- better efficiency

 

Best regards

Sergej & Alex

 

4D – propeller for aeromusical in combination with reversible ESC

 

The aeromusical category is quite popular. To be able to perform crazy 4D maneuvers the model requires among other things a reverse thrust drive configuration. The MAMO upside-down VPP system is well-established and technically proven drive configuration. But this system requires a good knowledge and experience in troubleshooting in case you have problems. Furthermore, maintenance and repair after a crash is not to neglect.

 

Over recent years the drive configuration with reversible ESC become more and more popular.
Due to improved ESCs regarding reverse dynamic and response time overall setup has made a step forward but for sure still not comparable with performance with a MAMO upside-down VPP system.
But due to easy handling of reversible ESC drive configuration it is perfect for beginners and extend flying possibilities to perform 4D maneuvers.

 

Many pilots asked us if we could produce some special 4D propellers for a reversible ESC drive configuration with the target to improve overall performance of such solution.
This year we had time to sit down and reflect the input from pilots and their feedback about actual available propellers and drive configurations. After that we started to develop a new 4D propeller with the main target to increase overall performance significantly.

 

The result is following new 4D propellers for reversible ESC drive configuration:

     -           4D – SG 08x3.8                  weight 1,4g

     -          4D – SG 09x3.8                 weight 1,5g

     -          4D – SG 10x3.8                 weight 1,6g

 

     -          4D – SG 08x4.3                 weight 1,4g (soon available)                      

     -          4D – SG 09x4.3                 weight 1,5g (soon available)

     -          4D – SG 10x4.3                 weight 1,6g (soon available)

 

The main influence at dynamic performance (fast response and reverse) of 4D propeller is the weight of propeller and mass distribution. The motor has a maximum available torque (T). Depending on moment of inertia (J) from propeller the system has a maximum angular acceleration (a) of propeller during reverse situation à  T = J x a à Increase angular acceleration by using a motor with higher torque (use motors with low rpm/V and motor with more power) and decrease moment of inertia (J) of propellers. J = ∑ m_i x r_i². The lower the weight (m) and closer the mass distribution (r) to center of propeller, the lower moment of inertia (J) and better the dynamic performance of propellers will be. This is mandatory because of the reversible ESC principle that propeller has to be decelerated to zero and accelerated in other rotation direction.

But at the same time the propeller has to be solid enough in normal and reverse direction to avoid vibrations (lose of efficiency) under a thrust of 450 – 900g (test conditions of propellers) depending on drive configuration.

A special production method and latest available materials allowed us to come down with weight to 1,4-1,6g depending on size of propeller. Usually, 4D propellers are made of plastic and have a weight of ~4,6g.
Looking just at the weight we achieve already a 3x time better dynamic performance for a same configuration (4,6g/ 1,5g = 3,1). The weight distribution of the new 4D propeller is also closer to center comparting to a plastic propeller which also increase dynamic performance of propeller.

 

Well, that is all just theory. The most important is the performance at a model and the feedback of pilots! Attached you find a video which show performance differences between actual available 4D propellers and our new 4D propeller.

 

Video

 

The new 4D propellers are useable with our SG VPP 01 / SG VPP 02 / SG VPP 03 motors. 

 

PS:
Many thanks to Christian Oppliger for his tests and detailed feedback during development time.
Also, thanks to all other pilots which gave us input for the development of the new 4D propellers.

 

Best regards

SG-GLAVAK

Sergej & Alex