Changing 600Pro Tail Gear Ratio

[rotaryguy]

The umbrella gears are the same across both gears sets - .8 or .6 mod. Its only the drive gear thats different.

So a trex 500 cant even hold its own main gear in such moves? Its main gear is mod .6 and I had an old one that easily pulled 2 kW.

This gear set is the same mod thats been used in the 600N and 600e all along anyway just has the newer designed hub for the modified one way sleeve.

[matchbox]

Originally Posted by rotaryguy

The umbrella gears are the same across both gears sets - .8 or .6 mod. Its only the drive gear thats different.

So a trex 500 cant even hold its own main gear in such moves? Its main gear is mod .6 and I had an old one that easily pulled 2 kW.

This gear set is the same mod thats been used in the 600N and 600e all along anyway just has the newer designed hub for the modified one way sleeve.

Sorry Rotaryguy, your right in that fact. I did really explain what i ment very well. I didn't mean the 0.6 mod gear by itself, but the whole package it can be used with.
Using the original 0.6 mod (3.85:1) with 95mm tail blades and a governed headspeed of 2200RPM is still pushing in a peak of 2.5KW. And the 0.8 mod (4.5:1) with 105mm blades at 2200RPM has similar power output.
If the headspeed is push up to 2300RPM in either of these setup's it wears the umbrella gears out very quickly, even at a faster rate than the 34T or 40T tail drive gears wear.

The 3.85:1 with 95mm @ 2300RPM revs excessively and the 4.5:1 with 105mm @ 2300RPM puts to greater inertial load on the gears. Either create a lot of wear and risk a gear breakage.
So if you don't take the head passed 2200RPM with these setup's and you don't do hard piro stop maneuvers; everything then maybe ok.
But I brought this Heli to feel the performance difference over my other heli's and for it to still be reliable.
That is why i have stuck with the Pro's stock gear drive and went with higher head speed.

[Helico-pteron]

Originally Posted by smaze17

Thanks for the report

I too will just be putting on some 102's and calling it a day. I'm flying her at 2000, 2125 & 2250.

I like how she flies at 2250. Seems perfect to me.

S

Agreed, running my gov at 2250 really has me convinced this is the right HS.

Now, if I could use the stock tail without mods I'd be a pig in sh*t!

[smaze17]

Originally Posted by Helico-pteron

Agreed, running my gov at 2250 really has me convinced this is the right HS.

Now, if I could use the stock tail without mods I'd be a pig in sh*t!

At my current skill level, the 95's are fine. I have only been flying for 5 months so there's no way I'm good enough to blow the tail out at 2250. I just put the 102's on there anyway

S

[OzDruiD]

Originally Posted by OnTheSnap

Parts:

http://grandrc.com/p7255/H60121-Torq...duct_info.html
http://www.align.com.tw/shop/advance...d89f&x=43&y=14

I bought one at : http://www.experiencerc.com/store/h6...ex-p-8897.html

You need both the new auto gear and one of the older tail drive gears. Both linked above.

In relation to doing the tail ratio mod, can anyone confirm if this "3" pack of front torque tube gears - "H60147-01 Torque Tube Front Drive Gear Set" is the same teeth\size etc as the one listed above (H60121). 3 pack seems value for money if you have mates with 600 PRO's

http://grandrc.com/Elec.-Helis-&-Par...duct_info.html

PS.. already have the correct auto-gear (H60020t)

[OnTheSnap]

Originally Posted by OzDruiD

In relation to doing the tail ratio mod, can anyone confirm if this "3" pack of front torque tube gears - "H60147-01 Torque Tube Front Drive Gear Set" is the same teeth\size etc as the one listed above (H60121). 3 pack seems value for money if you have mates with 600 PRO's

http://grandrc.com/Elec.-Helis-&-Par...duct_info.html

PS.. already have the correct auto-gear (H60020t)

There are only 2 types of 600 tail drive gears. The old and the new. Those are the old style which you can use if you changed the tail ratio.

[Homer]

Lost control of the tail yesterday, going back to the original tailratio, resulting in a severe crash.

When i first changed the tailratio to 4.5, my 600Pro flew ballistic, rocksolid.
But after stripping the front and rear umbrella gears in midair, also resulting in a crash btw, i didn't have a spare 0.6 umbrella gear laying around, so i decided to change back to the original tailratio (which i'm certainly never gonna do again), with the forementioned result.

Reading about "not having enough autority in the tail", made me a little sceptical, but now i know better, it's a real shame that Align made this critical error, there's not much Pro about this 3.8 tailratio.

Homer.

[matchbox]

Hey Homer, what headspeed are you running?

[OnTheSnap]

Sorry to hear about your crash homer. Sounds like an exact repeat of my experience. At sbout 2350 things seem pretty good. But at 2200 it's pretty dangerous IMO. Been a rough summer for me as well. 4 big crashes so far. A few RIP Lipos along the way too.

I'm still running 105's and liking them. No issues at all. But switching to 4.5 is still tempting.

[Homer]

Originally Posted by matchbox

Hey Homer, what headspeed are you running?

Normally i run all my heli's on 100% throttle, but with the 600Pro i run at 80% governed by my Kontronik jive.

I'm sorry, but i have no idea what headspeed this results in.

[Homer]

Originally Posted by OnTheSnap

Sorry to hear about your crash homer. Sounds like an exact repeat of my experience.

Thanks, i felt silly, because i normally have an escapescenario at hand, but this was too much for me to handle, lost the tail twice due to the excessive speed of the flight. (which was rocksolid before, with the 4.5 ratio).
It's makes a day and night difference.

[Blueabyss]

Yesterday on my second flight of the day and 3rd flight total, I decided to push it a little. I don't use governor mode just flat curves. 80 85 and 90flat. Took off in normal mode 80flat and flew around a little to bleed the battery off a little before going to stunt 1 85 flat. After about 30 seconds I hit the switch to Idle 1 and started some aggressive front flips gaining altitude by going heavy on the neg collective while in the inverted portion of the flip. On the third consecutive flip I could hear the head speed dropping and then BAM.. Totally lost the tail while partially inverted at about a 60 degree angle nose down. It started to whip the tail and was falling out of the sky. Pulled the collective back to neutral and was just getting ready to hit throttle hold when the tail finally bit some air and became stable. VERY close call.. I flipped into idle 2 and finished the flight just doing big air stuff like big loops and fast low fly-bys. I did get the nerve up to take it up high and do a tail slide into a backwards loop.. One of my tests for a gyro's holding power. I am using a VBAR by the way. It held and I landed soon after.. This tell me the tail letting go was from head speed drop and not gyro as it held fine in the backwards loop. Also tells me 85% flat curve is not even enough head speed for mild aerobatics. Now this makes me want to do the gear ratio change but I heard Homer talking about stripping the gear due to the .6mod. 90% and above throttle curve get into extreme head speeds so now I don't know what to do with this thing.

Chris

[OnTheSnap]

No tail will hold during a bad bog. Running the governor you'll see much better results. Of. Course the tail will hold better during bogs with a higher ratio or 105 tail blades. I use 105 tail blades with Vbar gov and my tail is ridiculously bullet proof. Also check that your tail limits are correct. Even a fraction on an inch of less travel makes a big difference.

As far as stripping gears goes, the main weak point on the ESP has been the front umbrella gears. Never had an issue on my pro, but I assume the same is true. With the tail gear ratio change, the umbrella gear design is unchanged, so this is not a concern. The reduced mod on the auto gear has never been an issue in my experience. So I really don't see an increased risk with the tail gear ratio change so long as you run 95 tail blades and an RPM of 2250 or less.

[Blueabyss]

Thanks for the advice snap.. 2250 really does not fit my flying style.. 2300 is prob the bottom for me. I talked to one guy who sets the gov at 2400 and raises the avg voltage value to 48 in the castle fooling it into thinking its ok. He says it maintains 2400 as long as the voltage holds up then it just is like running a 100 flat curve.

Chris

[OnTheSnap]

I tried 2350 with a flat curve and the tail was locked in. But I was using good packs that did't produce much bog and 12 degrees of pitch. Also at extreme headspeeds that you like, you can run less pitch. Perhaps just back off your max pitch a little until you find the practical limit for your power system. Up the headspeed instead of the pitch to get the results you like.

Faking the castle software is pointless. Just enter the headspeed you want and ignore the warning. No matter what the gov does the best it can with inadequate overhead.

Next you could try a 14T pinion and KDE motor mount. Infinity hobby has a slant 14T I believe. But you need a couple of washers to interface to the counter bearing. Or green loctite on the motor shaft may work.

Another expensive idea is to try the Vbar gov. At 2250, my setup feels like 2400 with 65C packs (running 35-45C). It's that good IMO.

Just some ideas to get you out of your hole. Definitely don't change the tail gear ratio and try to run 2300+. It'll likely cause a tail gear failure.

[Blueabyss]

OTS post your vbar file.. I would like to compare it to mine.

Chris

[OzDruiD]

Originally Posted by OnTheSnap

Just some ideas to get you out of your hole. Definitely don't change the tail gear ratio and try to run 2300+. It'll likely cause a tail gear failure.

So ..the 0.6 tail gear doesnt hold up to the power ratio?
Reason I ask is that I stripped one out.

Green box - undamaged
Red box - top "edge" of teeth rounded\flattened off.

I was setting up the Castle ESC calibration for auto-bail out and "on the ground".

Yes, I didnt follow the castle video "EXACTLY"
Yes, I did it at the field with the gears engaged.
yes - stripped out the older 0.6 mod gear.

How? No #@$#@ idea. I setup my curves and such, increased the thold values up etc, the thing spooled up and suddenly went to BALLISTIC head speed, by the sound and speed - AT LEAST 2500 or more before the gear shredded and I managed to kill the motor via reducing the T\Hold percentage.

I have sneaky suspicion (going over it in my mind) that I MAY have connected 1 x 6S to the "Y" lead (which also feed the CCBEC pro and vbar) then plugged the "Y" lead into the ESC. Motor boots up and only detects 6S, I didn't hear the cell count and guess I didn't realise what I did because I was so quick to plug in the other 6S. BTW - this is all assumptiom, I cannot actually remember what I did in what order.

I replaced the gear and followed the process step by step again, all ok, the auto-bail out is now calibrated and the gear didnt strip out .. but concerned about

1) 0.6 mod tail to auto gear mesh ....see picture, only the "very" top edge of the tail gear is flattened over.. as if its poorly meshed.. but .. we cannot adjust the mesh, so WTF?

2) brings to light - at what head speed does the older 0.6 mod tail gear becomes poor choice..

[matchbox]

Just a thought Blueabyss. I found it better to run my pitch between 10 and 10.5 degs. It will reduce your chances of bogging the motor down. And with 2350 rpm, it still gives heaps of punch. (with the stock tail gears)
Personally i've never seen the need to run my blade pitch over 11 degs on any of my heli's, let alone 14 deg or more.
Also, flat curves are easy to setup, but really loose out badly when the throttle is set below 90%. This is where a governor helps heaps, because it will give the motor full throttle when the head bogges down and then back it off again when the load drops. All the while maintaining the set headspeed.

[OnTheSnap]

Originally Posted by OzDruiD

So ..the 0.6 tail gear doesnt hold up to the power ratio?
Reason I ask is that I stripped one out.

Green box - undamaged
Red box - top "edge" of teeth rounded\flattened off.

I was setting up the Castle ESC calibration for auto-bail out and "on the ground".

Yes, I didnt follow the castle video "EXACTLY"
Yes, I did it at the field with the gears engaged.
yes - stripped out the older 0.6 mod gear.

How? No #@$#@ idea. I setup my curves and such, increased the thold values up etc, the thing spooled up and suddenly went to BALLISTIC head speed, by the sound and speed - AT LEAST 2500 or more before the gear shredded and I managed to kill the motor via reducing the T\Hold percentage.

I have sneaky suspicion (going over it in my mind) that I MAY have connected 1 x 6S to the "Y" lead (which also feed the CCBEC pro and vbar) then plugged the "Y" lead into the ESC. Motor boots up and only detects 6S, I didn't hear the cell count and guess I didn't realise what I did because I was so quick to plug in the other 6S. BTW - this is all assumptiom, I cannot actually remember what I did in what order.

I replaced the gear and followed the process step by step again, all ok, the auto-bail out is now calibrated and the gear didnt strip out .. but concerned about

1) 0.6 mod tail to auto gear mesh ....see picture, only the "very" top edge of the tail gear is flattened over.. as if its poorly meshed.. but .. we cannot adjust the mesh, so WTF?

2) brings to light - at what head speed does the older 0.6 mod tail gear becomes poor choice..

It sounds like a sudden RPM change stripped the gear. This is abnormal and I wouldn't hold this against the gears.

The slight alignment issue is common and appears on my Align Heli's. The problem is that the main gear can be positioned slightly higher or lower depending on washers used, etc on the main shaft. As long as it's only a mm or so it's not really an issue in my experience.

Since the old gear set increases the tail gear ratio to 4.5, I wouldn't push it past 2200-2250 or so.

[Weule]

I'm abusing the old gears at 2350 without issue (Jive, 65C TP). However, the tail was better at 2300 using the old gears and 105's.

I'm running Edge main/tail but fear a blade strike with 105's as there is about a 1/2" overlap. I'm sticking with the old gears for now...