Jermo
12-06-2006, 08:07 PM
I spoke with support at HH and my BCX is on the way back. They checked it out and brought it back up to "factory specs". If the heli still has the tail drift issues after 1+ batteries I'll be working on a true solution to resolving the issue.
Because this issue is inherent to the 4 in 1 unit it's to our advantage as a community to fix this. I've seen the threads about cutting up the reciever case and canopy but believe that the fix is likely simpler and may not require cutting of the case or canopy.
2 technical causes of tail drift are attributed to this unit:
1. Varying battery voltage - (anecdotal evidence states this is only an issue with Lipos and that Nicads don't experience the issue as bad)
2. Thermal drift of the gyro - I believe the close proximity of the motor control Hexfet is heating up the gyro causing it to drift.
I'll be looking at each cause individually, making changes, and recording results.
I plan to look at cause #2 first.
Hypothesis - Hexfet heat in proximity to the Gyro causes or significantly contributes to the drift.
Plan - remove the hexfet and power recitifiers from the 4 in 1, relocate them on a board, add a heatsink, bridge the connections as necessary to use the old motor connections for power into the board and control signals. Connect the battery and motors directly to the external Hexfet assemby (ESC at this point).
This plan/design may change depending on what's available and the ease at which the typical hobbiest can duplicate the design IF it proves to be successful.
Plan for cause #1
If the excessive drift issue still exists to a large enough extent.
Monitor and record Gyro supply voltage over time as the battery is discharged. If the supply voltage is the issue test with a voltage regulator design to further stabilize the circuit. Zener Diode design most likely.
Depending on the outcome of these experiements and tests I'll post results, drawings, and steps to duplicate my work. If the hypothesis are found to be false then we'll start over.
If we find a viable resolution I'll submit it back to HH for consideration.
I plan to do this while my T-Rex is being constructed and not flyable.
I'd like to also state that I've been a harsh critic of HH. I feel my comments have been overly critical. I tend to always strive for perfection yet rarely attain it. This trait causes me to have high expectations.
I apologise if my comments have been inflammatory that is not my intent.
Jermo
Jermo
Because this issue is inherent to the 4 in 1 unit it's to our advantage as a community to fix this. I've seen the threads about cutting up the reciever case and canopy but believe that the fix is likely simpler and may not require cutting of the case or canopy.
2 technical causes of tail drift are attributed to this unit:
1. Varying battery voltage - (anecdotal evidence states this is only an issue with Lipos and that Nicads don't experience the issue as bad)
2. Thermal drift of the gyro - I believe the close proximity of the motor control Hexfet is heating up the gyro causing it to drift.
I'll be looking at each cause individually, making changes, and recording results.
I plan to look at cause #2 first.
Hypothesis - Hexfet heat in proximity to the Gyro causes or significantly contributes to the drift.
Plan - remove the hexfet and power recitifiers from the 4 in 1, relocate them on a board, add a heatsink, bridge the connections as necessary to use the old motor connections for power into the board and control signals. Connect the battery and motors directly to the external Hexfet assemby (ESC at this point).
This plan/design may change depending on what's available and the ease at which the typical hobbiest can duplicate the design IF it proves to be successful.
Plan for cause #1
If the excessive drift issue still exists to a large enough extent.
Monitor and record Gyro supply voltage over time as the battery is discharged. If the supply voltage is the issue test with a voltage regulator design to further stabilize the circuit. Zener Diode design most likely.
Depending on the outcome of these experiements and tests I'll post results, drawings, and steps to duplicate my work. If the hypothesis are found to be false then we'll start over.
If we find a viable resolution I'll submit it back to HH for consideration.
I plan to do this while my T-Rex is being constructed and not flyable.
I'd like to also state that I've been a harsh critic of HH. I feel my comments have been overly critical. I tend to always strive for perfection yet rarely attain it. This trait causes me to have high expectations.
I apologise if my comments have been inflammatory that is not my intent.
Jermo
Jermo