My 2 cents on installing retractable landing gear on phantom 2v+ V3

[boglll]

Hi, don't want to discuss about pros and cons of Retracting gear, I just was curious to try it and I did. As I had to cope with something different from various howto you may find, I want to share my experience to help someone else. I bought hml350 V2, to have minimum amount of extra weight and because is triggered using the tilt knob of my stock RC (NPV581). to have an idea:

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I studied this video to understand basis:

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difference n.1: I couldn't insert servos cable through a hole in the air vent as in my phantom there is a PCB on the inner side of the air vent; for this reason I had the wires pass through the holes where the gear is attached to the body, polishing the hole just a little as the jumper is too big. see: IMG_0394.JPG
difference n.2: The X2 cable is NOT to be removed from NAZA, just plug it out on the receiver side and put the gear module in between (that's why is provided with female jumpers and not male...). In picture you see where X2 on Naza is hidden, use the other side! see: IMG_0389.JPG
difference n.3: compass module is (not) molded: trust youself and with a little knife or cutter or whatever open its little box and take it apart from the landing gear (sorry no pictures...)
difference n.4: the gear module: it is different from this but not in the procedure ::

pay attention from time 1.20: this is the procedure to trim open and close, otherwise will open for half the length or overclose. see: IMG_0391.JPG note red and blue circle for the switches. TIP: if you want to reset trimming and do it again push 3 times quickly the corresponding button, or play in some way with buttons until you get it... It took me 10 minutes of trying to figure out its logical.
difference n.5: the compass holder doesn't fit the compass. I put it in place and with little pieces of foam I fixed the compass in the holder. Put also a spare shock absorber into the cable (you see it on the left of picture) IMG_0396.JPG .
difference n.6: just like n.1 but for compass cable... I opened a little hole in the body. Note also the usage of the shock absorber to keep the compass in place... IMG_0395.JPG

Final result is this: IMG_0397.JPG

I had only indoor test due to bad weather, Gear works exactly as in the first video, I was able to calibrate compass so I assume it works normally. One more important thing: when Phantom is off, landing gear servos are in idle so if you move it the gear is free resulting in unwanted opening...

Hope this helps, regards

 

[RoyVa]

Sure did, showed me a lot of pain for no gain.

 

[sdtag]

wow that is a big help. thanks a lot.
I bought the same kit but I am modding it to be automatic at about 5 feet with a Arduino and a ultrasonic sensor.
I know I know, what's the benefit from all this work? Well, I like to tinker and it's fun and it keeps me out of the bars at night. haha
mine is still on my desk. Probably be another week or two for my completion.
Thanks again, this is one area where I lack a little, documentation.

 

[boglll]

QUICK UPDATE: I tried a quick flight but I experienced an important drift. Went home to start an advance calibration ( not done after the installation) but is 2 days of continuos rain... Or could be the compass, which now is closer to the quad body ( and you calibrate it with engines off). Be careful when testing...
Btw automatic gear will be even better, when done please share!

 

[sdtag]

I got the compass out of the leg but how do you mount it in that arm?
I saw your picture how you did it. No offense but I don't like it.
I did it my way. I super glued the arm to the bracket then tie wrapped the compass and cable.
I cut a notch in the seam where the two halves come together to pass the cable through.

 

[boglll]

No offense, seems we both like pain with no gain [emoji6] . I see your compass older is facing downward, mine is upward... And your is much "clean" to see, if this by word translation makes sense for you. I don't see clearly how you stitched the compass to the holder, can you show a picture from another point of view? (And explain how to embed pictures...). I have the doubt (due to my drifting) the original leg holder shelters the compass, so thinking about how to provide something similar. Bye

 

[sdtag]

here is another angle.
I used tie wraps - wire ties - to attach the compass and cable to the arm.



When you are typing a reply there is a button below and to the right that says Upload a file.
Click it, choose your picture and upload. Cursor placement seems to play a role in picture placement so be careful. Afterwards you will have the option to insert the full image or a thumbnail.

 

[boglll]

We have the same orientation but mine is inside the cylinder (as it is upside down), the connector is too big, so it remains outside and this is why I put the shock absorber on top. Thanks for the how to!

 

[yo-dude]

Very Interesting. How did it work out? I installed mine in a similar way on a P2...but I keep getting severe drift, I am started to break parts of my bird, Am thinking of taking it off all together.

 

[yo-dude]

here is another angle.
I used tie wraps - wire ties - to attach the compass and cable to the arm.

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**** How did it work out? I installed similar stuff on my P2 and kept getting severe drift...and now I starting to break off parts... Yours worked ok?

 

[boglll]

After first attempt with severe drift, I did advanced cali + compass cali + rc cali. BUT second attempt resulted again in severe drift leading to hard landing... Good thing is that if you are experiencing drift just like me, this means it's not our installation fault. I removed the new gear adapter and resumed standard conditions. During the weekend I should be able to test if I'm back to normal. My doubt is the new compass location is much closer to the chassis/engines than the original, and the original compass is somehow sheltered inside the gear, while in the new location is mainly "open air"... BTW during flight n.1 I had a KP index of 6, in flight n.2 KP=2 (still having to understand if KP index is something to worth about...).
I'll let you know test n.3 results.

 

[sdtag]

My compass is fine. I calibrated it and everything seems normal.
Maybe it was the K index. I get nervous when it is over 4.
My problem now is I'm not a programmer and I'm trying to teach myself C+.
I get a lot of false readings on my ultrasonic sensor so when it is flying at 100 feet the gear comes down intermittently. below my set point of 3 feet it is solid thank God, but the false triggers are driving me nuts. I have to code something like look, wait a sec then look again. If the 2 answers match then lower the gear. Right now I have it looking 4 times in 2 seconds and it still does it. I'm kind of stalled out at the moment but I'll get back on it. I'm about ready to strap some feathers to the gear so it looks more like a bird flapping it's wings. haha

 

[boglll]

Maybe pcb placement? @sdtag: where did you put it (picture?)? You are the only one not having drift at present. Sorry not being a C programmer for your problem. Regards

 

[yo-dude]

After first attempt with severe drift, I did advanced cali + compass cali + rc cali. BUT second attempt resulted again in severe drift leading to hard landing... Good thing is that if you are experiencing drift just like me, this means it's not our installation fault. I removed the new gear adapter and resumed standard conditions. During the weekend I should be able to test if I'm back to normal. My doubt is the new compass location is much closer to the chassis/engines than the original, and the original compass is somehow sheltered inside the gear, while in the new location is mainly "open air"... BTW during flight n.1 I had a KP index of 6, in flight n.2 KP=2 (still having to understand if KP index is something to worth about...).
I'll let you know test n.3 results.

---- thanks for that.... Yeah we are in the same boat for sure... I am not sure about KP index? viewable in iOSD? Like you I (just) put my original gear back on... Hopefully I will have time to test it tomorrow...Will let you know... Another fellow made a good point...that the compass is really sensitive to machine proximity...makes sense. I was worried about that even befor I INSTALLED it. It think the way to go is use 1 leg from the standard legs...with the compass... leave it there...then install struts right under the bird... I saw it somewhere...will look for it... Retractable looks cool...but I also think they are unstable.... compass unreliable and will mess up the angle of the antennaes as well... Thanks again

 

[boglll]

I did a quick test today. P. Seems not so "stuck" in the air when you release sticks, I mean it took a few seconds to get a steady position, but was a windy day. NO drift at all, switching from Gps to atti and back with no issues. I check kp index using hover app, today was 1. Don't think antennas may be the clue: I left them untied from the gear and they are more or less vertical, even retracting the gear they remain just a little bit more angled, but this could interfere only when far from Rc. Btw I never was able to test the gear "live", I crashed before...Still thinking about compass, even if mr. Sdtag seems had no troubles... @ sdtag: 2 cents on your problem: maybe ultrasound are jammed by props down drift. Try putting sensors inside cylinders to prevent air turbulence to be detected (a sort of sheltering...) as terrain.
Bye

 

[yo-dude]

Hey.... Just curious...do you have a Phantom 3? not sure what you mean by sensors... I hav only a lowly Phantom 2. I took out my retractable gear and returned everything to orginal state...Recalibrated everything... Took it out for a test
this a.m. and NOT GOOD. a bit more stabel but the drift returned. not as quick but still as bad... 2 crashes... I am thinking my compass is out fo whak ...yet it reads ok...? Any thougts?

 

[Davowalshy]

I saw something about IMU calibration the other day that might help. Sometimes the phantom is not completely level for many reasons and even if it is calibrated on a completely level surface its still not really level. This can cause drift, The way to compensate for this is to record which way it is drifting and recalibrate with paper sheets under the legs of the phantom to lift it in the opposite way of the drift. For example if the phantom drifts forward recalibrate after putting a few sheets of paper under the front leg pads to lift up the front of the phantom slightly. You may need to increase the amount of paper to increase the angle height if it still drifts. It's time consuming and its trial and error but rewarding once you get the drift under control. Its kind of like using trim on the remote. Same concept.

 

[yo-dude]

I saw something about IMU calibration the other day that might help. Sometimes the phantom is not completely level for many reasons and even if it is calibrated on a completely level surface its still not really level. This can cause drift, The way to compensate for this is to record which way it is drifting and recalibrate with paper sheets under the legs of the phantom to lift it in the opposite way of the drift. For example if the phantom drifts forward recalibrate after putting a few sheets of paper under the front leg pads to lift up the front of the phantom slightly. You may need to increase the amount of paper to increase the angle height if it still drifts. It's time consuming and its trial and error but rewarding once you get the drift under control. Its kind of like using trim on the remote. Same concept.

Very good point. however my drift is so severe that I lose control and have to cut power and ...well...crach the bird before it is too far away....

 

[boglll]

yo-dude: I have a p 2v+ v3.0, hope to test better during weekend; I'm talking about sensors as sdtag is developing an arduino automated system, using ultrasound sensors instead of rc. BTW: I'll check better for drifting and eventually try the paper method.
regards

 

[yo-dude]

yo-dude: I have a p 2v+ v3.0, hope to test better during weekend; I'm talking about sensors as sdtag is developing an arduino automated system, using ultrasound sensors instead of rc. BTW: I'll check better for drifting and eventually try the paper method.
regards

Thanks for that. Arduino... sounds ambitious! Actually my retract system would be ok, then sometimes would go crazy and start flapping around too... and I could not get it to behave without messing up my camera, which was why I was putting it in in the first place... Best of luck to you. I am going to have to get my machine serviced... I have had 6 hard impacts and I don't want that any more. Have you ever had your machine serviced? thanks again