DoubleCH's flight log

[DoubleCH]

So now that I've maidened my 300X quite successfully (that I didn't crash haha), I know I have lots of data to gather and things I need to work on so instead of posting new threads on each issue I'll just create a thread for my flight log from now on. It'll be easier for anybody to find info on my flights, my work on my bird, and my mods. And OTOH it'll be easier for those who aren't interested in those. It'll be just one thread to skip.

Anyways, my 1st real flying day after maiden was a bit disappointed partly due to the weather and partly due to a combination of other things, but I want to emphasize that I'm not disappointed at the 300X at all so far.

Let me start off with 1st flying day log (flight #2 to #7, copied and edited from my YouTube clip description.

Flying weather window is small these days so even though knowing it's going to be windy I still can't pass up the opportunity. Good news is nothing really bad happen today. Bad news is it still needs some work after today to fly good. First off, one of the cyclic servos failed as I predicted from day 1. Right out of the box, 1 of the cyclic servos sometimes can't be moved by hand when not powered while the other 2 cyclic servos move smoothly by hand. When powered however, all servos work fine and seem plenty strong. Today the questionable servo finally stopped working on initialization. It's just dead. After unplugging the battery, fiddling a bit (won't budge), re-plugging in the battery and it worked again. At that point, I decided it's not worth the risk. I've already called HH from day 1 and should be receiving a replacement servo soon.

Onto the BeastX. I guess my lack of experience with full-blown FBL controller shows. I was expecting the 300X-specific default settings with BeastX to be pretty close to good enough but after some post-flight investigation, looks like I've been running way too low cyclic gains for the day thinking something was wrong. Also, the cyclic gain dial on the BX has a much larger range than the 130X gyro gain user-programmable range. I guess that makes sense since the BX can be used on a vast range of bird size so the cyclic gain range has to be large enough. Plus now that I think about it more, it's apparent that the 300X-specific default settings for cyclic (and tail) gain is for a good starting point to guarantee no head wobble (or tail wag) and I'm supposed to have to dial up gains until wobble then back down a little. Makes sense since the default 54 tail gyro gain of range -100 to 100 on DX8 was too low. I was able to bump up to 65-70 without tail wag. Comparing how much swash tilt with gyro on bird in hand motor off with 130X and 300X, the gyro gain setting on BX that I ran the day was probably lower than the lowest gain possible (-10) on 130X. And I didn't like anything below -5 on the 130X. Probably would've figured I was runny too low gain the whole day sooner if it wasn't because of the strong wind pushing the bird around all day long. I was blaming the wind because my friends' bigger birds weren't much better in the strong winds. Hopefully will see if I can get some userful data from indoor test hover to confirm that too low cyclic gain was indeed the culprit.

One-way-bearing mod... It works good in that it didn't explode but I didn't plan to do auto any time soon. I just wanted that mod in early to eliminate the whiplash stress on the mainshaft Jesus bolt. However, after a closer look yesterday on the 450X OWB, looks like I've got a dud and the cage for the needle bearings is crooked. Sooner than this report here version 2 OWB mod is up already with a much better quality "German" OWB from T450, some mainshaft sleeve from KDS 450, and some good old machine work to connect the rest. See my one-way-bearing mod for more details.

Wood blades... As I expected, I knew I couldn't wait for my fav LHS with discount to re-stock the CF blades, but instead just get them without discount at my next fav LHS. I was hoping some of the above issues could've been fixed by the CF blades, which BTW one blade is too thick at the root. I'm kind of afraid cramping the grip down will stress it too much and break over time. Turns out the wood blades are actually not too bad. Running them at 75% throttle, 13 degree collective pitch and 14 degree cyclic pitch I can still kind of tic-toc it (except for the gyro gain issue that almost made me crash). Because of the above issues, I was not brave enough to run 100% throttle with the CF blades yet so I still haven't felt the full power yet.

Anyways, here's 2nd flight of the day. Too bad I didn't tape 1st flight of the day which was better. But as usual, I always get the cam curse. It could've been worse. Looking forward to the next flying weather day to test out my new BX settings and OWB v2.

[Sailingnuts]

Awesome. Thanks for putting it together.

[GSPI]

This will be fun Double CH! Thanks for adding your log here.

[65L88]

I have a feeling this thread will be a potential sticky candidate.....

[DoubleCH]

Flight #7 to #10. The good, the bad, and the ugly...

After the OWB v2 update and tail rotor dynamic balance, the bird is now as smooth as it can be. And it shows in today's flights. I've also cranked way up on the BeastX dials:
Dial1 cyclic gain: 3.5 marks above center
Dial2 Direct Cyclic Feed Forward: almost 4 marks above center (default)
Dial3 tail gain: 3.5 marks above center

The good... Both test-hovers and today's flights show no sign of head wobble and only tiny tail wag on gyro pos2 which I deliberately set to higher than necessary (60, 65, 68). No tail wag at all with 65 and below. Cyclic and tail response is almost as quick and direct as my 130X.

The bad... It's still windy at times today but it's actually a good thing because it proves that with much higher gyro gains, the bird is not as susceptible to wind.

The ugly... I was pretty happy with the settings today until my last flight of the day. About 30 seconds in the air, I lost cyclic for a fraction of a second. It's not a Rx brownout because throttle stays on (my failsafe throttle has been set to zero). It's also not because of vibe confusing gyros because in which case user input would've higher authority than stabilization authority. Instead I had absolutely zero cyclic control. It was like the servos got no power. I wonder if it's because of the one bad cyclic servo (that HH has already sent out replacement for) seized up and drew too much power from the BEC.

Luckily, I was just hovering and the swash was tilted just a bit forward. There was enough time for it to stay up in the air before I got cyclic control back. I couldn't reproduce the problem and all servos seemed to work good with good power so I just flew the rest of the pack and it was all uneventful until almost end of flight and it happened again. This time I just finished a forward flip back to upright so the swash was stuck in quite a forward tilt position and the bird just nose-dove towards the ground fast. I prepared for the worst and hit TH about 1-2 seconds before hitting the ground at high speed. Luckily, I got cyclic control back just in time so with full elevator back and full pos collective I tried to bleed out as much airspeed and headspeed as possible. Turned out it was almost a perfect auto. The bird just tipped over the last fraction of a second. Apart from some dirt on the tail-fin tip, one main blade tip, and one landing gear post, everything else was fine. There's not even a scratch on the canopy. I cannot imagine if the cyclic control didn't come back or came even just a second later. That was real scary.

I'm tempted to change out the stock ESC with one that I can flash BLHeli onto and perhaps run a redundant external SBEC. I've been so spoiled with BLHeli governor and that I keep forgetting with stock ESC I cannot flip to idle-up and expect soft-start every time. Plus although it doesn't seem like a common problem, I don't trust the stock ESC BEC.
[ame]http://www.youtube.com/watch?v=h5C2FlQG4DU[/ame]

[sbarro]

Originally Posted by DoubleCH

Right out of the box, 1 of the cyclic servos sometimes can't be moved by hand when not powered while the other 2 cyclic servos move smoothly by hand. When powered however, all servos work fine and seem plenty strong. Today the questionable servo finally stopped working on initialization. It's just dead. After unplugging the battery, fiddling a bit (won't budge), re-plugging in the battery and it worked again. At that point, I decided it's not worth the risk. I've already called HH from day 1 and should be receiving a replacement servo soon.

Ouch, now you got me worried. I have two of these birds. The servos on one of them move freely by hand, but with the other, all the servos are stiff enough that It feels like something could break if I forced them to move by hand.

[DoubleCH]

Note that the one questionable servo I have when it's movable by hand it's either smooth or totally unmovable, not somewhere in between. I found out the problem is that the plastic shaft (part of the middle housing) for the 1st gear either got worn out or gone bad in the molding process (remember my problem is right out of the box not even flown) such that gear mesh between motor pinion and 1st gear was so little sometimes I can get 2 pinion tooth tips wedged with 2 1st gear tooth tips like shown in the pic. Notice in the pic that although the 1st gear looks like it's stripped. It's not. It's the white lithium grease that's filling up the root of the teeth making the gear teeth look short.

It's possible that the only time the servo can be seized on power up is if I wedge the teeth bad before powering it up. Most other times when I managed to wedge the teeth, powering it up will free them. I kind of fixed it by coating the plastic shaft with CA and smoothed it out. No more wedged teeth when moved by hand.

[DoubleCH]

Earlier flight of the day before the lost-cyclic incidence. Flies much better with cranked up gyro gains and OWB v2.
[ame]http://www.youtube.com/watch?v=j7Y3bV6hB4o[/ame]

[DoubleCH]

One last flying weather day before the series of rainy days to come so I couldn't wait til my warranty parts to come for more testing. The motor is still vibrating a bit at high RPM so I limit HS to 75% throttle at zero-pitch (~3000rpm) to limit vibration. Still haven't tried full throttle on this bird since my 1-week ownership. Too bad, will have to wait till motor replacement.

Like my 130X when new, after every flying day I would do more post-flight checks than normal because this is the crucial time period where parts are more likely to fail from defects. My OWB v2 mod is still holding up well but I took the time last nite to re-shim the main gear wobbly out-of-the-box resulting in a smoother running bird. The main motor wobbly out-of-the-box however still vibrates at high RPM even after my balancing because I balanced by weight while the wobbly motor can still wobbles. My warranty replacement motor hasn't come in yet so I'll have to limit headspeed to ~3000rpm for now.

Had the Blade 245mm CF blades on today after quite some significant sending on one root because it was 0.1mm too thick. I was kind of worried about sending down to the carbon weave but I couldn't pass up the testing opportunity. I may retire this pair when my warranty pair comes in.
[ame]http://www.youtube.com/watch?v=QdVs63sBDg4[/ame]

With a throttle V-curve, HS was really lacking during continuous flips. I miss my BLHeli governor. That triggered me to run cyclic-to-throttle mix (adding up to 5%) and it actually worked pretty good.
[ame]http://www.youtube.com/watch?v=3s5FEH3IQ7A[/ame]

Perhaps adding up to 10% will work even better but I ran out of dry flying condition so I had to call it a day although I'm happy with today's progress.

Hopefully by next flying day I'll have the bad motor out and a whole lot of goodies in.

[Rollin_3z]

Chris nice flying. Its good to see you fly a bigger heli. I would have kept my 300 if I knew you would be flying a 300 as well

[R3L72]

Subscribed... DoubleCH, always provides indepth Information and Knowledge in Threads & Posts!

[SHYguy]

I've had it with the stock servos, it's MKS all the way in all my 300 and 450 helis now

Great tread!

[DoubleCH]

It's been quite a roller coaster ride with my 300X the last week or so I can't keep up with posting progress. I received my goodies from HK US warehouse last week including a Nanotech 6S 45C 1300 (no I don't plan on running 6S on the 300X I'm going to split it into 2 3S and I would've picked 25C but I couldn't wait from HK HK warehouse, there's no 3S Nanotech 25C or 45C at US warehouse), a Turnigy AE 45A ESC with 4A SBEC and governor, a 450-size 330W motor that looks amazingly similar to the Wicked motor only different kV, and other goodies. After flashing the 45A ESC with BLHeli, soldered in the connectors, it's time to give the setup a test hover indoor. At first, I just ran it with 10T which gives a little lower HS but more torque and power than stock. I think 11T will be perfect with a little bit higher HS and probably about 15% more power. With the governor, bigger pinion, and better fitting motor bearings, the thing hovered much more quiet and vibe-free I was like looking underneath the landing gear, "is it really hovering off my (test)bed?" Idled-up and did a few quick jerks on the collective and it felt good. I brought it down and wanted to check everything. Everything went well except the motor stopped faster than I expected. I was thinking, "hmmm... I didn't expect the magnets to be that strong". Nothing was more than just barely warm but I noticed my servos aren't jittering. That's when I noticed all power was out. There was no smoke no smell no nothing. Motor was free to turn but felt like electric brakes were still on even though gear mesh was perfect nothing was binding so I unplugged. I have had a few incidents before with different BLHeli ESCs that it would be like the electric brakes stayed on even without power. Most other times on the next battery plug-in it would be fine again. Not this time, when I plugged in the battery soon after unplugging and checking things out, bam! A saw some sparks from the ESC and that's it for its short life. I don't know if it's the FET driver design or if it's a bug in the BLHeli I've never felt comfortable with electric brakes staying on after unplugging battery. Perhaps in previous times I waited long enough for the FET gate capacitance to discharge and release the electric brakes before I plugged in battery. This time perhaps one set of FETs are still on while the initilization beep turns on the complementary set and that caused a dead short.

Without the ESC I didn't want to risk running the more powerful motor with stock ESC so I took the motor out as well preparing for the nice sunny flying weather weekend. I was so heart-broken especially when the combo seemed to work pretty good. I'm willing to give it another try so I placed another order for more of those 45A ESCs. The motor and ESC may be overkill for now. If everything goes right (please pray for me for no more mysterious frying ESC), I'll probably try the ESC first with stock motor. Then perhaps try rewind my bad stock motor just to see if I can get good enough power out of it. There's still quite some room in the stock motor to stuff more copper (hint: more power) in. If the 45A ESC works good, I might put one in the 450 (shhh).

[DoubleCH]

Flight #14 to 22 on Saturday March 2nd. Weather was perfect with sunshine and warmth (I actually got a little sun-burnt) and I've got my Nano 45C 6S 1300 pack separated into 2 3S 1300 packs. First flight of the day it all went well and then all of a sudden I lost cyclic control and it dropped from 30ft high onto some relatively soft sand. It's not the 1st time I lost cyclic control and/or throttle since day 1. I always thought it was the defective servo and/or wobbly motor. Most of the times I lucked out when the bird's trajectory was not going down when I lost control. Not this time. Amazingly, the only damage was a broken tail case and a slightly bent tail shaft. After some improvised fix with the tail case and fixing the tail shaft and dialing down collective and cyclic pitch ranges it's up in the air again! I took it easy on the next flight at first to see if it would happen again but it never did. From flight #15 to 22 it was all uneventful. I've opened it up to flat 100% TC and everything went fine. I was happy again and I decided to try my luck again with the 45A ESC so I placed order with HK US warehouse on Monday and more goodies will be here tomorrow, thursday and please pray for my good news to come next tomorrow and no more frying ESC.

[DoubleCH]

Flight #23 on Monday March 4th. Weather was OK for flying. Noone was at the park at 1st so it's time for the 300X. Time to try out the little cheap tach I bought to see how it works out. I think it works OK but I'll have to find a better way to secure the tach. Perhaps stick it to the heli and hover with it next time.
[ame]http://www.youtube.com/watch?v=x4O9DR6Lbts[/ame]

Flight #24 right after. Perhaps because it's not as warm as saturday afternoon, the lost cyclic/throttle control problem re-occurred. First I was in a hover not even loading the servos or motor and the cyclic and throttle cut out. Luckily, it came back quick and the bird didn't even drop a foot. I brought it down and checked everything I could. Nothing was out of the ordinary. Range check couldn't have been better at at least 40 paces with bird orientated with antenna at the worst directions. Spooled up again and it stuttered a short burst on the ground. After that everything seemed fine so I gave it a go. It flew fine until I tried to do some tic-tocs and it happened again. It was pure luck that the bird was on its upward trajectory when it happened and I was able to save it. After that I decided it's time to pack it in and fly my 130X instead.
[ame]http://www.youtube.com/watch?v=wSvPi_zyS04[/ame]

[DoubleCH]

Flight #25 on Tuesday March 5th. Weather was marginal and I knew the rain would be coming but I couldn't pass up the opportunity to diagnose the problem more especially with the warranty claim replacement motor and cyclic servo in which clearly work much better than their defective counterparts. I bought a DSMX remote Rx (to prepare for my other new member to the family, shhh) and installed it temporarily to the 300X hoping it was brownout that caused the problem. Bad bet. The problem happened again and this time it took a bad hit. It was on a level flight when all of a sudden the bird started to lean right. It's not the roll of death induced by vibration where you should still get some cyclic control. The bird was running as smooth as it ever could and I lost total cyclic control. The cyclic was totally dead. It hit on its side and bent main shaft, feathering shaft, cookie-cut the head dampers. Broke canopy and looked like that's the extent of the damage.
[ame]http://www.youtube.com/watch?v=X76mF36jXbc[/ame]

[DoubleCH]

Flight #26 today March 6th. Since it's not a brownout issue I was determined to find out the cause before contacting HH. I installed an external BEC to see if it helps. Upon fired up, the difference is obvious. The servos work strong and now pass my usual cyclic servo stress test which is to lift the entire heli by one cyclic servo. The stock DS76 cyclic servo is rated at 1.75kg-cm which means at 1.1cm moment arm it should be able to lift 1.6kg, almost 3 times the weight of the heli. Afterall, these servos are rated for the 450X. Before the external BEC, on a good day a cyclic servo could barely lift the heli while on a bad day it would stall. I thought that's the way stock servos are like. I've been like lazy flying because of the servos acting slow all these times. My 300X cyclic response is more inline with a good performing 3D heli. I hope HH sees that there's more than enough evidence to show that the ESC is bad and hopefully replace my crash damaged parts as well.

[R3L72]

DoubleCH, Excellent Catch

I've been following your Posts and your ESC find would explain alot on the issue of Brown-Outs with this Heli. JustPlaneChris has a lot of documented sudden power cut-outs that would happen after hard Cyclic inputs and sometimes at random.

As the weather gets more flier friendly here in Germany, I plan on rebuilding my 1st 300X (~72 flights) with some aftermarket components but haven't yet decided on gutting the electronic's. I do wish there was a more plug-n-play motor & ESC combo. Since I still need to practice my soldering skill, maybe an external BEC would work for now.

My 2nd 300X, at 74 flights is still going strong and the only thing I've done with that Heli, besides installing Edge 253mm CF main blades, is dynamically balance the tail assembly. Knock-On-Wood, nothing goes wrong with my 300X #2 this flying season. I plan on keeping my 300X's until they hard-break or a better 300 sized Heli is made.

Thank You for documenting your progress thus far!

[DoubleCH]

Originally Posted by R3L72

I've been following your Posts and your ESC find would explain alot on the issue of Brown-Outs with this Heli. JustPlaneChris has a lot of documented sudden power cut-outs that would happen after hard Cyclic inputs and sometimes at random.

Yeah, I've read a few posts from him and others about power cut outs but haven't read anything about BEC not doing a good enough job. I still haven't ruled out BX being the culprit, but with external BEC that stays about 5.0V both the BX and my servos are happy so I'll stick with the fix with a better external BEC or a better ESC altogether.

[DoubleCH]

Here's the external BEC I'm using from HobbyKing US warehouse with Buddy Code valid til March 12th. Get them before they run out or before Buddy Code run out. Actual output voltage is 5.22V no load and dropping down to no lower than 5.1V on the bench. I would not try 6.1V output with stock servos though. A $3 part that fixes a $300 problem. I don't know if I should laugh at it or laugh about it. Or you can get the Castle 10A for $25 if you don't trust HK stuff.
http://www.hobbyking.com/hobbyking/s...dProduct=28248