I met Mark at the field, yesterday, after work. He spent some time during the week going through his G820 checking everything and installing a GV-1.
Initially, Mark wanted to wait for me to get out of work and meet at the field, but I told him to get out there early and practice / warm up! He did and put a couple of hover flights on his G820. Mark let me check the controls out for forward flight on the next flight…shortly after arriving. I made a couple adjustments in his radio, decrease the gyro gain some (the longer boom and longer tail blades makes the tail more responsive), and add some expo to the rudder. The rudder was just a tad sensitive around center.
Once the settings were made, it was time to take to the skies! It was poetry, that big heli and the low frequency woofing from the blades was unbelievable! Not to worry Raja, you will get to see this “mammoth” Aug. 1st. Yea, Mark is bringing his G820 to IRCHA. It cruses through the air without a care, and once I was happy with it, it was time to see how it autos.
It has the tendency to bleed off most of its head speed close to the end, but everything on this heli is new and we are still working on the motor break-in and we are getting used to much bigger blades. The 4th flight was Mark’s turn to see how it flies to him. He liked it a lot, and took my recommendation to just cruse around the field, figure “8” style until the motor is broke in and I tweak the controls for a more aggressive feel…like his G4, but a little at a time. The YS120SRX motor, even though very rich, has more than enough power for this G820. I could have performed mild 3D and this motor wouldn’t have noticed.
And now for my turn! I finished the repairs to my N7. The fan hub had worked its way up (or off) the crankshaft forcing the clutch into the clutch bell and placing side force on the two support bearing holding the clutch stack causing the bearings to melt! Long story short, I replaced most everything in the stack. I too ordered a YS120SRX motor from RC Japan and Heliproz (Amain Hobby). The 120 motor from RC Japan showed up first, so it became the new motor for my N7…with a Hatori FAI style muffler.
So now it’s the moment of truth, first flight. I did my normal pre-flight check (I need to revise this as you will read in a bit), and checked the needle settings one last time. It took a bit to get the motor started with the right amount of throttle trim. And I was off!
The motor ran fine for the first flight. The tail had a twitch every now and then, mostly due to the rich needle settings…normal. Even during a couple of autos, the motor ran just fine. But things didn’t get crazy until the second flight! I filled the tank, and checked everything over, started the motor, put the heli into a hover, and I’m off and flying. I do many hovering piros, left, right, holding it in one place.
I start flying around, figure “8” style. Bill decided to leave and yelled out to us goodbye. I gently roll to inverted, motor is running fine, I have a nice forward speed going…Bill’s watching, Mark is by me, and BAM! 5 feet off the deck and the tail goes out. I try to gain control, but nothing is there! I tell myself…half flip, half flip, but the hands don’t know what to do! I’m dumb-founded, and I just watch my heli smash into the ground in the worst way possible…but in my mind.
I’ve seen this many times and all I can do is wait for it to happen. This sucks! A newly repainted canopy (it looks awesome by the way), a new motor & muffler (second flight), and not to mention a new heli. This flashed in my mind as I watched it drift away from me. Spinning slowly inverted. I said “NO!, Not this time” I waited for the tail to come around and attempt to flip it right side up…it didn’t want to. So I flipped into throttle hold and hovered it close to the ground until the blades almost stopped. My N7 landed on the head without breaking anything…well, bent one blade link, and stripped one aileron servo horn.
I couldn’t figure out why the tail let go at first. As we walked up to the crash site, I tried moving the rudder and nothing happened? Servo? Linkage? I took the canopy off, no cracks or dings by the way, and saw the link had popped off the rudder servo? We searched the area for parts and found nothing. We walked back to my truck for a thorough inspection. Come to find out, the aileron ball had popped out of the servo horn as well (the nut was missing!). The rudder link was broken, possibly due to the crash. And the cause of the tail loss was a pin in the front transmission crown gear had come out allowing the crown gear to spin freely on the jack-shaft.
My conclusion is; this heli was destined to crash in some fashion. The broken rudder link would have happened when I tried practicing piro-flips. The ball link would have happened at any time while in flight. The pin holding the crown gear to the jack-shaft was a God-sent. That pin caused the least amount of damage compared to what could have happened! Damage parts…lost a pin, bent a blade link, stripped a servo horn, lost a nut, and broke a plastic link… But still, I have no idea as to why the pin came out. That was the second time I landed my heli inverted without much damage!
Prior to the second flight on my N7, Bill has made great advances in his flying skills! He attempted rolls and back flips! Bill was having problems with the first couple of rolls…coming out cork-screwed and falling. I ran out to him and instructed him on what he needed to do. Rolling to inverted was ok, but he would add up elevator rolling to right side up. And he didn’t use any negative pitch while inverted. So I talked him through a couple of rolls and he was doing them a whole lot better.
Then it was time for the back-flip, the same problem applied here as well, no negative pitch. So I had him break the flip into two parts. Once inverted, he quickly learned to add enough negative to hold his heli up. Bill got so excited at learning this, he almost ran out of fuel performing roll after roll and flip after flip. That alone made our day, watching someone else finally getting how to do a maneuver(s).
So all-in-all, it was a great day! I think the YS120SRX is going to be a great fit for my N7!
"I love the smell of Nitro in the morning!"
