Covering Pressure Hole?

[spartan2381]

I was wondering if anyone has any experience with covering the pressure hole with cotton or breathable foam to help with wind turbulence between the frames. I know the open source APM guys cover their sensor to help with the turbulence from the rotors.

 

[PeterLester]

Seems to make some sense but I am almost scared to try now...... check out my aerial video here. Wind was light but quite gusty..... you can hear the motors suddenly surging multiple times and the altitude changing randomly multiple times. The during the RTH there are some big surprises......slew forward to 4:12 seconds and on....... MR is jumping around on the ground like a jack rabbit.

This is WKM firmware version 5.20 and the MR is a custom 800mm frame with a brushless gimbel and GoPro3 Black on board. https://www.youtube.com/watch?v=Dti_bPGPaRg

I was wondering if anyone has any experience with covering the pressure hols with cotton or breathable foam to help with wind turbulence between the frames. I know the open source APM guys cover their sensor to help with the truculence from the rotors.

 

[spartan2381]

@Peter - I see what you mean, the wind was defiantly kicking from the sound of it. I could imagine that the frame is acting like a wind tunnel and could be affecting the pressure sensor.

I'm going to try some gauze and maybe a breathable band-aid and see what results I get. Hopefully it won't end in a crash....

 

[EastCoastJib]

Any updates on this?

 

[spartan2381]

I was out today doing some testing with the pressure hole covered with surgical gauze. With my vertical gain is at 180 on the S800, so far it's holding altitute very well. I gave some aggressive movements with no change in altitude. Wind was about 8mph.

To install I cut a small 2 layer section of the gauze and used some electical tape to hold it taught over the pressure hole. The gauze seems to provide a nice buffer to any wind entering the frame.

I'm going to do some more testing tommorow and see how it goes.

 

[gtranquilla]

Yes..... I moved the IMU down onto the anti-vibe plate which is on the landing gear and most of the issues disappeared with respect to the surging motors..... But then the RTH was not functioning correctly...... It would come back over the original takeoff point at 60 feet but would go up inside of come down. So I moved the batteries as well as the camera/gimbal system closer to the MR center of gravity to reduce angular momentum. Then it would come back and hover for a very long time before gradually dropping..... Finally I fine tuned the camera gimbal PID loops to help prevent gimbal oscillations on the landing gear.... Now it comes back provided there is no wind and/or only a very light and steady breeze....... Next I will fine tune the Basic P and I gains to eliminate remaining wobble which seems to occur from time to time in gusty conditions. I expect then a more reliable RTH c/w self landing and motor shutdown.

Any updates on this?

 

[Benjamin Kenobi]

I've covered mine with some porous foam and mounted on the anti-vibe plate. No white flashes and perfect altitude. That was with no wind.

I wonder if we could drill another small hole to relieve static pressure build up like they have on V2?

 

[CrashMaster]

From day one my WKM has had gauze and sticky plaster on it and have flown in 20mph wind without a flinch or wobble. The WKM sits in the centre between top and bottom frame plates so is like a tunnel where it sits.
(XAircraft X650 Pro Carbon)

 

[spartan2381]

I was out testing in the air today for about an hour and had rock solid position hold with the pressure hole covered with gauze. My WKM is mounted in the defined location on the S800 but I used the red 3M tape with an anti-vibration plate (http://www.amainhobbies.com/product.../207389/n/Skookum-Anti-Vibration-Mounting-Kit) and than another layer of 3M tape to hold the WKM. So far this has worked really well. Hopefully I get some more time this week to go out and record wind speed and get some video of the S800 holding position.

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