Swivel nozzle for F-35b and Yak-141 VTOL

Rotary nozzle for your F-35 or Yak-141 VTOL model with EDF size 70mm.

The nozzle can have two workers and one random position. This is possible using the three-position switch on the transmitter. In this configuration, you cannot set the exact intermediate position of the nozzle with a single touch of the switch.

For assembly, inexpensive standard components were used, except for the nozzle itself, of course:

• N-motor with different speeds, (motor1 is 2 times slower than m2) shaft 10mm

• Steel balls 2.5mm

• PCB from two servos

• SMD resistors 1206

• PCB universal desoldering board

• Gear 12 teeth module 0.5 - 1012DF

• Micro switch KFC-V-307

The rotary motors are controlled by the servo board, I replaced the potentiometer with four resistors so that the motors stop when the limit switch is pressed, they are located on the board and soldered to the switch terminals, you can see this in the photo.

The procedure for selecting resistors is perhaps the most tedious task in the world. First you need to measure the resistance of your potentiometer (usually it is 5K), then determine the position of the potentiometer at which the servo motor stops, unsolder the potentiometer (without disturbing it) and measure the resistance between the end and middle terminal, you will get the resistance of R1 or R4 (depending on which side you turned the potentiometer) and the sum of the resistances R2 + R3 + R4 (or R1). Do this for the left and right positions. To simplify, you can take R1=R4 and R2=R3, then you need to take the measurement only once.

With careful selection of resistors to eliminate drift, both motors can be connected to one channel, but it is much easier to use two channels and trim the end and middle points in the transmitter.

The nozzle can be upgraded with a stepper motor and have flexible position configurations. In this case, it will be possible to control the nozzle along the Yaw direction by 10 degrees.

You can find more details on the forum https://www.rcgroups.com/forums/showthread.php?4318183-Yak-141-70mm-EDF-vtol

The model is adapted for FDM printing, the use of resin printing may cause excessive backlash, but you can try it.

I used PETG plastic and a 0.16mm layer with 100% infill.

https://www.youtube.com/watch?v=qnuHevgjKKw

https://youtube.com/shorts/xALf2U9Le8U?feature=share