V-22 Osprey Project - Prototype 1 Ending

-

I'm calling an end to the first prototype build for this project.  A few things changed between the first attempted flights.  I gave the thing a serious diet by:

  • replacing the wooden boom with carbon fiber and redesigned/reprinted the motor mounts
  • replaced the separate ESCs with a 4-in-1 drone ESC module
  • replaced the Frsky X4R with a FrSky XSR
  • replaced the 2S 2000mAh battery with 2x 1S 600mAh batteries in series
  • replaced the Arduino Mega with an Arduino Micro
  • generally lightened everything up where I could
The new all-up weight is 217g, but it's still too heavy and the tolerances in these micro helis aren't good enough.  I tried a few hanging control tests, and there's so much slop in the control linkages that it ping-ponged all over and never stabilized.

For Phase 2, I have a pair of KDS 450 helicopters that I'd like to use for the next prototype.  They run on 3S 2200mAh batteries and are certainly more capable of lifting a larger airframe.  They are also more capable of doing damage, so safety is going to be paramount.  I think the control system is sound using the Arduino to mix the flight controller outputs.  Better tolerances should lead to less slop and more authoritative control.  Initially, I'd like to modify as little of the helicopter airframes as possible in hopes of returning them to separate helicopters if this prototype also fails.  The plans, for now, are to remove the tail rotor assemblies and figure out a way to connect them together with a fixed boom similar to my 1st prototype.  I've already checked, and it is possible to reverse the motor and the one-way bearing to have the two rotors counter-rotate.



Stay tuned for more!

Comments

Post a Comment

Popular posts from this blog

V-22 Osprey Project - Flight Control

-
Image
Now that I have a conceptual idea of how to build a V-22 using leftover mCPX BL parts, how do I go about controlling such an aircraft? I own a Taranis X9D+, and it can control up to 32 channels using dual receivers, so that won’t be a problem. I’m sure that I can create a mixing profile in the transmitter to handle just about anything, but I’m also sure that just like any multi-rotor “drone," this thing will need some form of automatic flight stabilization. I own a few multirotor aircraft and I’m familiar with how they function. Some research into the popular flight control software (Betaflight, iNav, Cleanflight, LIbrepilot, etc.) all came up short. No one has written code for off-the-shelf flight controllers to manage a dual-swashplate aircraft. I would have to build my own. I have not delved into writing code for flight controllers, but I have built a number of Arduino projects, and some of them utilize RC inputs to control servos and motors. It occurred to me that I
Read more

V-22 Osprey Project - Design Changes for v3

-
Image
It's been a busy end of 2021, and as we start 2022 I'm getting closer to building version 3 of the Osprey wing.  The single biggest problem I've faced is the amount of backlash in the direct spur gear drive of the tilt mechanism.  It introduces some nasty instability that, left unchecked, would likely destroy the model in flight. I've investigated other tilt mechanisms, but the one I keep coming back to is the rack and pinion design that Tom Mast uses in his model at Rotormast.  His design uses a high-torque digital servo with a small pinion gear driving a rack attached to the rotor nacelle.  The servo has been modified with an external potentiometer that's driven by a gear on the translation tube to give positional feedback to the servo.  I like this design a lot because 1) It works, and his model is proof, and 2) it requires less torque from the servo and has less backlash. I ordered the pair of modified servos, potentiometer, and rack from Tom's site and star
Read more

V-22 Osprey Project - Tuning and Setup

-
ESC SETUP I used two Castle Creations Talon 60 ESCs for the V-22 Osprey.  These ESCs are high-quality with an electronic governer designed for RC helicopters.  Other ESCs with this feature are recommended.  Using the CastleLink software and USB dongle, I set the following RPM parameters: Throttle Setting 2-blade 3-blade 20% 2600 2000 70% 2600 2200 100% 2800 2400 As with any standard airplane or heli it's important to calibrate the ESC endpoints as well. TILT SERVO SETUP The HiTec D85MG servos are digital high-torque metal-gear servos that are programmable.  Using the HiTec programmer, I set the 1000us endpoint to the forward flight (0 degree) position and the 2000us endpoint to the hover (90 degree) position, with the 1500us center point in the middle (45 degrees).  The programming of the servo is a bit challenging, as the endpoints set in the programmer coordinate roughly to 900us and 2
Read more