Oops, There Goes Another Main Gear...

[skigolfmike]

This time I got most of a flight. Basically, it melted. Fortunately I was doing a test hover to check the Gov Mode on the CCHV85 that I setup in RPM mode. The one still in the hub is the one I melted and the other one is the one I powdered. The gear mesh was not too loose this time. If anything I had it shaded a little on the tight side. See below.

Looks like I need to get the Gaui gears and try that. 14/50 or 16/60 should be pretty close.

[michael88997]

yea the gaui gears are lasting on mine with the z30... im runnin 50/15

[skigolfmike]

Looks like 15/60 or 16/60 will give me what I want. 13/50 is going to be close too.

I'll just get the 13-16 pinions and the 50 and 60 main. I have a spare 61T from the main shaft I can use too.

On top of all this I decided to turn my Blade 400 into a lawn dart tonight too.:arggg:

[michael88997]

dang that bites... i wish i had a 450 size heli... i want one really bad so i can fly everyday but that money issue :/

[skigolfmike]

The only thing I had left flying last night was my Arrow foamie. At least I didn't crash that.

I'm thinking the stripped gears are happening because the bearings wore out on the OWB shaft. The shaft had a lot of play. I got new bearings with the new gear, but I didn't install them. Maybe I should have. I put in the new bearings last night and it too out most of the play in the shaft. I'm thinking these might be a candidate for a better quality bearing.

John at ReadyHeli seems to think the 1400kV motor is the culprit. I don't know if that's true or not. I was running similar head speeds with the H18 power sucking pig motor and I changed the gearing appropriately.

Anyway, I put in my order for the Gaui .8M gears. I will try them when they get here.

This has been an expensive week. Got new gears and an optical tach for the 550. Spent a bunch on a night setup for the Blade 400. Then I stripped the gear in the 550 and I crashed the Blade 400 hard. Next time I'll know better than to try new maneuvers at twilight with something that small. My 55 year old eyes ain't what they used to be.

[skigolfmike]

I talked some more to ReadyHeli about this problem. It's not the head speed that is the kicker here, it's that the Scorpion -1400 motor doesn't bog even at those head speeds and the drive train wasn't designed to handle that much power.

It works like this, the load on the power train goes up exponentially as the head speed increases. Any rapid collective changes further increase the load. Even the 1100kV/1500W motors bog a little at that head speed, but the -1400 doesn't. I guess the main gear wasn't designed for that.

So, time to rethink the strategy here. I think I will go for 2200-2300 to take a load off the head. That should still have plenty of power and even at full pitch won't put the same load on the gear train. 15/61/20/61 is 2381 @ 95% efficiency. That should give me enough headroom for the governor to work.

[mjdee14]

I Scorpion -1400 motor doesn't bog .

Mike you sound happy with the Scorpion?

And by your signature your just running it with 6s 3300's ?

How ould you compare it to the Z30? ifyou can?

[ke6d]

So, time to rethink the strategy here. I think I will go for 2200-2300 to take a load off the head. That should still have plenty of power and even at full pitch won't put the same load on the gear train. 15/61/20/61 is 2381 @ 95% efficiency. That should give me enough headroom for the governor to work.

2300 rpm is a very scary headspeed :) I installed a Scorpion 1210Kv motor with 13T / 20T OWB and stock gearing last weekend. My TC curve is 90, 87, 85, 87, 90. Using a Skytach, my son was able to get a headspeed of 2350 at hovering. I proceed to do tic-toc for several minutes. My FlightPower 3300 mA EVO30 packs were done at 4:30 min. The current put back was 2600 mA. Motor temp at end of flight was 128F, ESC 130F, Bat: 125F. The motor was not bogging at all. The heli was actually gaining altitude during tic-toc at first until I got better at collective timing. I have had 8 very hard flights with the EagleTree recorder taking data. The stock gears seem to hold well. I was consistently pulling 60 to 63 Amp (1240W) without killing this motor. (it is rated at 1350W)

Can't imaging anything faster than 2400 rpm on this heli.

What were you doing before the gears stripped?

Dan

[michael88997]

Can't imaging anything faster than 2400 rpm on this heli.



mine was clocked at 2470 :)

[skigolfmike]

What were you doing before the gears stripped?

Hovering:wow2:

[ke6d]

Hovering:wow2:

Wow, hovering is less stressful to the gear train! Your new gearing combo seems OK. I would recommend to start with something like 85-90% for the TC then get an optical tach reading before increasing the TC. For governor mode to work best, you should not use more than 85% on the TC.

I used to run governor mode on my T-Rex 450 for while, but I switched back to fixed point heli on the CC ESC because I could adjust the TC for the desired headspeed easier.

GL,

Dan

[skigolfmike]

The new Phoenix Beta 2.00 software in governor mode, RPM mode, won't let you set an rpm that it can't hold based on the # of motor poles, motor kV and gearing. It's pretty slick and hits the selected head speed w/in a few %. Plus you can select 3 rpm ranges for 0%-49% throttle, 50%-99% throttle and 100% throttle. It's a breeze to program and it's right on the money as soon as you program it. Program the ESC, set your throttle curves and fly.

[skigolfmike]

I got a full set of Gaui pinions and I setup the heli with w 61T main gear. Initially I used a 15T pinion and programmed in 2200, 2250 and 2300rpm. I believe the calculator said it was good for 2385 rpm at 95% efficiency with the Scorpion 1400kV motor. After trying that, I wasn't real thrilled with the results. It was a little boggy on punchouts and didn't have the snap it had before. Next I tried a 16T pinion on and reprogrammed the ESC for 2300, 2350 and 2400 rpm. Much better. Actually, I like 2350 the best. Least bogging and best punchouts. Now, I just hope these gears hold up.:thumbup:

[JaggedEdge]

Sweet! You're really pushing some head speed. I'm looking forward to playing with the esc some more.

I got a full set of Gaui pinions and I setup the heli with w 61T main gear. Initially I used a 15T pinion and programmed in 2200, 2250 and 2300rpm. I believe the calculator said it was good for 2385 rpm at 95% efficiency with the Scorpion 1400kV motor. After trying that, I wasn't real thrilled with the results. It was a little boggy on punchouts and didn't have the snap it had before. Next I tried a 16T pinion on and reprogrammed the ESC for 2300, 2350 and 2400 rpm. Much better. Actually, I like 2350 the best. Least bogging and best punchouts. Now, I just hope these gears hold up.:thumbup:

[skigolfmike]

I ended up liking it best at 2400rpm. There is a little tail kick from the governor, so I might need to lower the governor gain a little. I'm on low gain now(7) so I might need to try custom 6.

I'm back to using 2400mAh in 4:30 though. I'm running standard timing now and I might try low timing. I might also try 8Khz pulse width instead of 12Khz. Those changes may make a little less power, but the motor should be a little more efficient.

[mjdee14]

I ended up liking it best at 2400rpm. There is a little tail kick from the governor, so I might need to lower the governor gain a little. I'm on low gain now(7) so I might need to try custom 6.

I'm back to using 2400mAh in 4:30 though. I'm running standard timing now and I might try low timing. I might also try 8Khz pulse width instead of 12Khz. Those changes may make a little less power, but the motor should be a little more efficient.

Mike...at that rpm what tail components are you running?

I get vibs from my tail that upset the gyro using the Gaui thrusted tail grips and new plastic tailbox & bearings.

[skigolfmike]

I'm using the CNC tail case and bellcrank from HeliDirect (Sonik I think), Gaui CNC slider and thrusted grips.

[mjdee14]

I'm using the CNC tail case and bellcrank from HeliDirect (Sonik I think), Gaui CNC slider and thrusted grips.

Mike...

Thanks...I have the cnc case/bellcrank and slider on myZ30 ship with Trex plastic hub and it runs smoothly....I tried the Gaui thrusted hub on that set up and it still vibrates so I guess I'll just duplicate my the one tht works....

[skigolfmike]

I have a T600 thrusted hub and grips sitting on the bench. Definitely works well. I took it off because it put the tail blades pretty deep in the grass. There was about a 5 point difference in gain (lower) with the T600 parts too. Most likely because of the bigger tail rotor diameter being more effective.

[mjdee14]

I have a T600 thrusted hub and grips sitting on the bench. Definitely works well. I took it off because it put the tail blades pretty deep in the grass. There was about a 5 point difference in gain (lower) with the T600 parts too. Most likely because of the bigger tail rotor diameter being more effective.

I just got a trexx tail fin set up $9.99 and it comes with a nice big horz fine and clamp also.....I removed the Gaui tail brace bracket and substituted the Trex...looks real nice with the bigger fins....