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Friday, April 13, 2018

RTGmodel.sk also released a nice F3K competition glider called Alatyr (the name is again coming from the middle age mythology, Alatyr means the father of all the stones) that is available since January. The plane is designed by J. Pejchar who is already behind several F3K design. The Alatyr is at the standard 1.5m wingspan, 1.04m length and feature a Pe16 airfoils for the wing and the HT22 and HT23 modified section for the tail. Quality of the kit, which arrives with nice wing bags, tail and rudder covers, is just oustanding, in term of fit and finish which is not surprising knowing RTGmodel quality. The wing uses a foam core. Component weights are the following:
  • Wing: 120 gr
  • Tail: 6gr
  • Rudder 5gr
  • Fuselage 31gr
The kit comes will all the necessary accessories, including a servo tray and servo frames for the alerons servos. Below is the link to the photo album

Wednesday, April 11, 2018


The flagship from RTGmodel (http://www.rtgmodel.sk/) has just received some evolutions and is now renamed Stribog+.

The main changes are the slim fuselage that is no more hosting ballast, and the apparition of a wing compartiment in the wings. Planform and airfoils of the wings remain the same and the tails is not modified.

Ballast for the joiner (628gr) and for the wings (1627gr) is provided and now allows to reach 2.2 kg compared to the 900gr of the Standard Stribog.

Moulding Quality is still second to none and some details have been added, like the servo tray front lips that are going up to remove the potential fuselage failure under the canopy. Component weight are the following:

- Left wing: 639gr
- Right wing:623gr
- Left tail including joiner: 42gr
- Right tail including joiner: 42gr
- Fuselage: 347gr
- Wing Joiner: 95gr

As a reminder, the Stribog is a very competitive and capable F3F plane. I have flown my unofficial personnal best in 26.21s with it.

Saturday, April 7, 2018

Review: Digital throw meter from Portachiavi.es

Today, digital is everywhere in our life, and starts to appear in basic tools to make our life easier. Everybody remember measuring aileron throws with a simple ruler holded in the hand, was not very accurate. Then appeared more sophisticated rulers positioned on the wing, and curved to ease the reading. It is more confortable, but the reading is still not perfect because you can have paralax error between the trailing edge and the ruler.

Portachiavi.es is a company based in Spain and specialized in 3D printing. Alex Gil, the owner, is also an aeromodeler who flies F3F in competition. Therefore part of the product range is dedicated to aeromodeling and sailplanes. Apart several model of digital CG balancers, for F3F/B/J, also F5J or F3K with better precision,  portachiavi.es proposes also a Digital throw meter that I review hereafter.

The Digital throw meter arrived with a metallic ruler to measure the control surface chord, which is necessary for the next step. The digital throw meter is composed of a body with 3 push buttons, and a power switch on the side. A cable, protected by a sleeve and 40cm long is terminated by the sensor, of small size.

The OLED screen provides a small but very good reading. On the 3 push buttons, 2 are to decrease or increase the chord parameter use to calculate the throw in millimeter. The third one, red, is to reset the zero position, at any time, which is very usefull when in speed or thermal position.

The Digital throw meter is very easy to use. Just tape the sensor anywhere on the control surface, the only constraint is that it need to be parallel to the hinge. Then, before starting, you quickly measure the chord of the control surface where you want to measure (at the root, or at the intersection with another control surface).

You then switch on the device, and wait 2 or 3 seconds. The screen displays "Click 0" to indicate to push the red button to do the calibration of the zero. Once done, you ajust the chord with the buttons + or -. You are now ready to star measuring or setting.

The precision of the measure seems to be around 0.1 to 0.2 mm, which corresponds to the fluctuation of the angle measure of the sensor.

The screen displays both angle and millimeter (I prefer the second one) at the same time.

I found the tool very convenient. The fact that only the sensor is on the control surface is a plus to read quickly on the screen that is not moving. I could measure the throws of my Quantum in 5 minutes.

I greatly recommend this tools. As we say, good flyers have good tools, and this one, like the Digital CG Balancer is a plus !

Note: Planet-Soaring readers can get a discount of 5 Euros on this product by mentioning PlanetSoaring when ordering.

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