Pitch pumps

[Greg Jackson]

My tail isn't really solid on hard pitch pumps now. Should I go down from the 2400 headspeed to maybe 2300 with the 12t pinion?  Rather have it hold well then the extra headspeed.  My tail is very smooth and I I crashed gain a little.  But just don't want something catastrophic to happen.

[curmudgeon]

The tail should hold fine with head speeds at or above 2,300rpm with either the 4.0:1 or the 4.5:1 tail ratio.  The tail rpm sweet spot seems to be between 9,500-10,000rpm for the 96mm tail blades.

You may need to adjust the "collective pre-comp", "governor gain", or one of the various tail gains.

[Greg Jackson]

Uh oh.  So do I need the pro software to do that?  Only reason I haven't updated to pro yet is because someone said it could fly worse if it is not set right.  How tough would it be or what would I need to do different than how it is in express?

[mfremont]

The tail should hold fine with head speeds at or above 2,300rpm with either the 4.0:1 or the 4.5:1 tail ratio.  The tail rpm sweet spot seems to be between 9,500-10,000rpm for the 96mm tail blades.

You may need to adjust the "collective pre-comp", "governor gain", or one of the various tail gains.

if my current HS is too low with the stock tail gearing to achieve a tail rpm of 9,500-10,000, should I expect that the tail will deflect to the right when I apply a quick stab of positive collective from a hover? and a deflection to the left when I reverse the collective quickly at the top of the climb?

I had that behavior on my E5 on its maiden flight today, even with the 3SX tail gain turned up all the way to 100. Tail hold was generally soft.

[FlamingHomer]

Hey guys,

I have changed my tail ratio to 4.5:1 and fly with headspeeds 1800/2200/2500 with the brain flybarless and the 95 tail blades. The tail is very nice. Can do much 3d figures with only 1800 rpm. With 2200 rpm the tail is very stable in all situations.
Love this machine.

Greets from switzerland

[steffgiguere]

If you are using V-Bar then you need pro to adjust the pitch pumps.

[matt_c_25]

vbar pro is well worth the money, just follow set up guides and it should vastly improve your e5, the swash leveller for high and low pitch is a great tool and the event log is very handy also


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[mfremont]

I have two vBars with pro firmware that I've been very happy with on other helis, but since I've only ever flown vBar I  decided to give the Bavarian Demon 3SX a try on the E5. To be honest, I haven't actually made much use of the extra tuning params in Pro, but I do like the setup and the vibration analysis mode.

My best guess as to why the tail isn't holding on my E5 is three-fold: friction in the slider, improper configuration of the gyro gain channel in the Tx, and low head speed with the 4:1 tail gearing. I'll report back after I've tried to fix these.

[Jeff_Barrett]

I have two vBars with pro firmware that I've been very happy with on other helis, but since I've only ever flown vBar I  decided to give the Bavarian Demon 3SX a try on the E5. To be honest, I haven't actually made much use of the extra tuning params in Pro, but I do like the setup and the vibration analysis mode.

My best guess as to why the tail isn't holding on my E5 is three-fold: friction in the slider, improper configuration of the gyro gain channel in the Tx, and low head speed with the 4:1 tail gearing. I'll report back after I've tried to fix these.

Any of the things you mentioned certainly can affect the tail. Did you size the tail links and test for smooth / easy operation by disconnecting the tail pushrod from the servo horn and actuating the pushrod by hand?

What's your exact setup in terms of radio system, servos, motor, battery, blade selection for main and tail, esc, and governor?

I am running the Demon on all my models and would be happy to share my setup files. I'm actually hoping Matt will give me a sticky to share them in another part of the forum.

When you say you're at 100% for gain on the demon, is that in your TX or on the diagnose screen? 100% on your TX might only be 60%-70% on your diagnose screen depending on your radio system. Mine is ROCK solid.

[mfremont]

After a couple of flights today it seems that the tail hold problem was largely attributable to a mistake in radio programming. I am using the GYRO feature of the 14SG to to control the tail and head gain but I failed to enable the tail GYRO setting in each of the flight modes. In every mode except HOLD the BD was receiving 0% (as reported on the Diagnose tab). Based on information in the BD manual, I believe that this resulted in a default tail gain of 20%.

Other contributing factors were a head speed of 2100-2200 RPM with stock 4.0:1 gearing and a sticky tail pitch slider.

I corrected the radio programming and confirmed that the BD software that it was receiving a gain of 55% in all flight modes, cleaned the tail shaft and confirmed that it was operating freely, and flew the heli today with a head speed of 2280 and 2380 RPM.

At 2280 RPM with 55% tail gain there was a very slight deflection of the tail opposite the main rotor direction at initial application of hard collective. At 2380 RPM with the same gain, the deflection was smaller. Even with this slight deflection, the heli flew well, and stops from a piro were crisp with no bounce or hesitation. On my second flight I increased the tail gain to 65% and it has almost no visible deflection in pitch pumps at 2380 RPM. Since there was no sign of oscillation, I'm going to continue increasing the gain and then back it down a little after hitting the point where it oscillates.

I am running the Demon on all my models and would be happy to share my setup files. I'm actually hoping Matt will give me a sticky to share them in another part of the forum.

I think this is a great idea! I'd love to see sticky threads, perhaps one thread per system in the respective model forums? To be helpful, I'm guessing we'd need to list the build details you described such as blades, servos, motor, ESC/governor.

I'd be happy to share my settings after another couple of tuning flights.

For the E5 I loaded the 550-600 Tail and Rigid settings linked in the BD forum on HF. It's a reasonable starting point, but it's clear I should increase the overall tail and head gain in order to arrive at more optimal settings. Not sure yet about the additional tuning parameters.

When you say you're at 100% for gain on the demon, is that in your TX or on the diagnose screen? 100% on your TX might only be 60%-70% on your diagnose screen depending on your radio system. Mine is ROCK solid.

This is a very important point. I had originally verified the calibration such that the % I set in the Tx resulted in the same % on the BD diagnose tabs for each of the gain channels. My mistake was failing to verify this in each flight mode. Had I done so, I would have realized I was transmitting 0% in NORM, IDLE1, and IDLE2.