nvrtd.design Blog

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 ro...

 At some point, I'm sure someone will ask me what all it took and how much it cost to build my version of the V-22 Osprey.  I sat down with a pile of Amazon receipts and compiled this BOM.  I believe I've captured all the component costs, but there will be some fudge factor.  For instance, I purchased the donor helicopters several years ago at a swap meet for $100 each, and I don't believe these are available any longer.  The KDS helicopter was, as far as I can tell, a clone of the popular Align Trex 450.  Similar clones still exist and parts are generally plentiful.  To date, this has cost me about half of what I could have purchased from Rotormast, so that's a plus. V-22 Bill of Materials

I took the Osprey out to my club field to start testing the transition into forward flight. It certainly got the attention of my fellow club members who were on site! The first two flights went off without a hitch. I was able to successfully transition the rotors to 45 degrees. I need to tune some additional parameters as the controls became very mushy and non-responsive. I think the rotor controls were phasing out before it had enough airspeed to make the flying surfaces functional. On my third flight disaster struck! I had been flying around just fine, but as I transitioned back to hover for landing it suddenly lost control and started pirouetting to the ground. I hit the throttle hold at tree level and it impacted the ground belly first. At the scene of the crash, I could see that the aluminum tube supporting the right rotor had pulled out of the wing enough for the rotor to flip 180 degrees to the left. I suspect that was the cause of the crash. The left wing broke the carbon...

Recently, I've been able to successfully hover the V-22 around the yard and start to tune some of the control parameters.  However, each of these flights is not very long and it has me concerned about battery selection and flight times.  The stock 450-sized helicopters recommend a 3S 2200mAh Lipo battery for an estimated flight time of 6 mins.  I started testing with two of these in parallel to make a 3S 4400mAh source for the Osprey. There's no beating around the bush, this machine is heavy.  Weighing in at 2lbs, 9.75oz (1186g) without batteries, it's a beast.  I've tried to be conscious of weight throughout the build, but with so much structure required for rigidity, it's hard to skimp out on materials knowing that any failure would be catastrophic. So what's the right mix of battery size to maximize flight time?  I had on-hand pairs of 3S 2200mAh, 4S 2200 mAh, and 4S 3000mAh.  To round out the selection, I ordered a pair of 3S 3300mAh batteries for ...