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RCExplorer Tricopter V4

JimCR120

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#22
It turns out there are a number of obstacles encountered when deviating from 10mm arms:

1) Arm thickness doesn't match front spacer thickness. This could be compensated by making a new spacer or adding to the one provided in the kit.
image.jpeg

2) The holes in the upper and lower body are drilled to tightly straddle a 10mm tail boom. This can be compensated by cutting notches for where the screws will pass.
image.jpeg

3) The tilt servo adapter has a groove to snugy fit a 10mm tail boom. This can be compensated by cutting away enough to allow it to fit.
image.jpeg

4) The provided H tool for tail tuning is made to fit a 10mm tail boom. This will be compensated by removing yet more wood to accomodate the tool.
image.jpeg

This last point is an important one as performing the tail tune enhances flight. While can't say from experience yet that it flies better with the tail tune done, I can say flight without out it is a bit difficult. Shhh, I got a bit impatient and took some shortcuts to sneak in an encouraging liftoff in the basement. Yes it happened. Yes I have a video.
 
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makattack

Winter is coming
Moderator
Mentor
#23
Nice! I'm following this as I just finished building and doing the initial tail tune on my rcexplorer V4tricopter which I've had in a box since slightly before FTFF2016. I saw one at FTFF built by Martin from Ottowa, CN who was camping near me and that motivated me to build it this past Winter. Actually... It was on my to-do list, but seeing his made me more psyched to do it.

This serves to basically replace my FT Electrohub tricopter running with a MultiWii/Flip1.5 flight controller running multiwii 2.4. That tri still runs well, but I've actually snagged the RX off it to put in a plane. It was my first multi-rotor build, and to keep things simple, I just used a PWM channeled RX (X8R) but ended up needing those PWM channels in a >4ch plane.

Anyhow, my experience with the ground based tail tune is that it's primary purpose is to define the servo limits and centering. If you have the feedback wired servo, it also serves another purpose, I think, but it seems you don't, so you can just manually setup the servo limits yourself. That's what I did with the MultiWii tricopter. I had to set the limits so that the servo wouldn't be overtaxed by the physical limits of the tail mechanism (I was using the FT "Indestructible Tail Mechanism").

It flew great!

I ran the in-air tail tune with my RCETri, and I do have the feedback wire. It took a whole 6 minutes and brought my 2200mah 3S battery down to about 11.9V by the time I was done. I honestly don't know what changed, but it's stable. Not the most responsive, but then again, I haven't touched the other tune values (PID's, rates).
 

JimCR120

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Site Moderator
#24
Nice! I'm following this as I just finished building and doing the initial tail tune on my rcexplorer V4tricopter which I've had in a box since slightly before FTFF2016. I saw one at FTFF built by Martin from Ottowa, CN who was camping near me and that motivated me to build it this past Winter. Actually... It was on my to-do list, but seeing his made me more psyched to do it.

This serves to basically replace my FT Electrohub tricopter running with a MultiWii/Flip1.5 flight controller running multiwii 2.4. That tri still runs well, but I've actually snagged the RX off it to put in a plane. It was my first multi-rotor build, and to keep things simple, I just used a PWM channeled RX (X8R) but ended up needing those PWM channels in a >4ch plane.

Anyhow, my experience with the ground based tail tune is that it's primary purpose is to define the servo limits and centering. If you have the feedback wired servo, it also serves another purpose, I think, but it seems you don't, so you can just manually setup the servo limits yourself. That's what I did with the MultiWii tricopter. I had to set the limits so that the servo wouldn't be overtaxed by the physical limits of the tail mechanism (I was using the FT "Indestructible Tail Mechanism").

It flew great!

I ran the in-air tail tune with my RCETri, and I do have the feedback wire. It took a whole 6 minutes and brought my 2200mah 3S battery down to about 11.9V by the time I was done. I honestly don't know what changed, but it's stable. Not the most responsive, but then again, I haven't touched the other tune values (PID's, rates).
I did buy the servo with feedback from RCE because it seemed a good idea though I admittedly understand little of what I'm doing. Thankfully this community is generous in sharing knowledge.

Today I hope to adjust the boom so the H tool will fit, perform the ground tail tune, and then the air tune (with a well charged LiPo, thanks). I'll probably do short test flights at each point to show the difference.

So now are you fully functional with your Tri? Got a video? Link?
 

makattack

Winter is coming
Moderator
Mentor
#25
No video yet. I'm pretty lazy and terrible with video content so I rarely bother to try. I still have to adjust the pids and rates so I may try a video on that. I like to use the *flight/multuwii profiles so I might try to demo the rc Explorer recommended vs my own to see which one I like more. I generally do in air tuning with an extra channel to select the component to adjust and another to go up or down in value.
 

JimCR120

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#26
In adjusting the tail boom to permit use of my H tool I neglected to hold on firmly enough to the boom and well... the saw ate it. Just the boom. Fortunately I've recently built 3 wooden booms so I was all practiced up for another but this time 10mm square baby! And the little H tool was on hand to check and recheck the work until it was just right.
Samson said it looked good.
image.jpg

I also used this time to rig up a more shock absorbing landing gear. I borrowed this idea from irekkin's tricopter and tried to make it work with zip-ties. We shall see if it's any good but I do think it's a step up from mere nails driven up into the booms.
image.jpg

Now back upstairs to set up the tail tune function with my radio through CleanFlight and get the next test flight in.
 

PsyBorg

Wake up! Time to fly!
Mentor
#27
hehe Make sure if you try air mode its on a switch. Them zip ties with it enabled WILL produce much drama upon landing.

Beautiful friend ya got there. Looks like my friends dog who just MUST check everything for chocolates and explosives that passes thru the door as my friend says.
 
#28
hey jim , here's what I've got. they're the biggest zip ties I can find (250 lb ). you can use two or three smaller zip ties to hold them on instead of the brackets. they just tend to move around.
DSCN1249.JPG DSCN1250.JPG
looking good, i'll be following along.
 

JimCR120

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#29
Houston we have lift off...

I still have the air tune to do. It's been a windy weekend and if it continues I'll make use of a gymnasium while not in use.

The tricopter was much easier to control but I'm not sure if the improvement can be attributed to the tail tune or the horizon mode that I put on my flight mode switch.

Am I correct in assuming Horizon mode is a stabilized mode? In Clean Flight I also see Angle mode and Air mode. Can anyone clue me in or directr me where I can learn about these?

@irekkin, I thought your landing was metal bands or something and thought I was doing something original with zip-ties... ha. Thanks for the tip on bigger zip-ties. I think I'll do that. Perhaps o anchor them I'll use electrical tape or heat shrink for a cleaner look. I do like the textured look on your booms. What is that?:cool:
 

makattack

Winter is coming
Moderator
Mentor
#30
Horizon mode is actually a little of acro and a little of angle. Think of it as an in-between mode where you can get full acro if you move the sticks beyond center, but if you center the roll/pitch/yaw, you get angle/self-leveling. Angle is basically self-leveling with angle limits, so even if you max out the stick, it won't go past a certain angle (resulting in a flip or roll).

Air mode is basically a special mode for 3D style flights where you roll and flip inverted. Usually, when inverted, you will want zero throttle, but normally, without airmode, if you drop throttle all the way, the PID controller doesn't start up any motors if you try to give roll/pitch/yaw input. With airmode, you can be at zero throttle and still control roll/pitch/yaw, causing the required motors to spin up as needed. Of course, this means, that if you're at zero throttle, you props might spin up randomly depending on what your TX is sending it. This is why people recommend not turning on airmode until you're actually in the air, and turning it off before you land. Otherwise, things might get a little exciting.

Nice job on getting your tricopter in the air! Yah, have patience with the in-air tail tune. I honestly don't really notice the difference in performance before starting the tail tune and afterwards.
 
#31
your tricopter is looking better all the time. maybe you'll get some calm weather and be able to get out and get some good airtime. the booms on my tri are 3/4 carbon fiber tube that I got from here, https://dragonplate.com/, I had bought it for something else that I never did. you can get it a lot cheaper on ebay.
 

JimCR120

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#32
TricopterV4 pitchng forward

Since the weather's been uncooperative, I did what I said I'd do. I took it to a gymnasium to attempt an in-air tail tune. No joy. I never flipped the switch because even in an air-current free space, the darn thing kept pitching forward in a slightly more than mile drift. With a little back pressure I could fly it decently enough but I've got 2 mini quads and an mSRX that do much better.

I've carefully done a leveled accelerometer cal running the level across the top of the top plate thinking to keep it the closet possible to the plane of the accelerometer. That said, the zip-tie landing gear aren't very level so I wonder if that could be an issue.

Another thing I was wondering is how much an imbalance makes a difference. In other words, does a multirotor care about CG. It seems like it would but I don't know if it would give me these symptoms.

Also, throttle resolution seems to be too touchy. Even with the gentle back pressure I can't keep it from a slightly more than mild ascent or descent.

Some thoughts I have for improvement:
The wires and ESC's need to be placed better. As they are ther is some binding where the wires flex entering the body when I fold the booms back and the ESC's don't completely clear the body.

I need better landing gear. I'll get some heavier duty zip-ties and try to install the to keep the body level while on the ground. Another option might be something that could keep this thing floating above the water.

An installed centering bubble level might help to ensure the tricopter is level for calibration/initialization purposes. I remember our discussion on another thread about the uselessness of stick trim and while proving everybody right and myself wrong I also saw how placing either my Inductrix or my Nano QX2 on uneven ground for initialization (the time after I plug in the LiPo until the loght stops flashing) messed up take-offs terribly. If this is also true for the tricopter then having a bubble level installed should allow me to control that variable. The other option is to have a board with levels that I could use for all my rotory aircraft.

I might shorten my booms. Right now they're 12" and I'm thinking of taking them down a few inches. I'm not decided on this and I porbably won't change it until I 'm proficient with the long legs.

It needs a battery tray. I have hobby plywood and can make a tray for the LiPo and a camera, maybe one of those new RunCam3's although the Night Eagle looked interesting too.

Speaking of batterys; what do all of you tricopter types prefer 3S or 4S? I've tried both and either seem fine but that low voltage buzzer seems to be set for 4S. With 3S LiPo's it beeps soon after lift-off. Does anyone know how to adjust the onboard alarm?

I'm considering different props. Eventually I would like this maneuverable but with endurance. As I understand it fewer and longer blades can give me more endurance.

Eventually this must have LED's.

I'm interested in having prop guards to keep this flying blender in check.

And lastly I would like this to make it an all-weather flyer by water proofing the electronis.


So there it is. Thoughts? Suggestions?
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#33
ok . . . a lot to unpack . . .

Since the weather's been uncooperative, I did what I said I'd do. I took it to a gymnasium to attempt an in-air tail tune. No joy. I never flipped the switch because even in an air-current free space, the darn thing kept pitching forward in a slightly more than mile drift. With a little back pressure I could fly it decently enough but I've got 2 mini quads and an mSRX that do much better.
Lets start with a bit of unhelpful advise . . . Have you tried flying it in acro? this would eliminate any pitching caused by poorly leveled accelerometers, since they wouldn't come into play. You may also just be that far out of tune :(

I've carefully done a leveled accelerometer cal running the level across the top of the top plate thinking to keep it the closet possible to the plane of the accelerometer. That said, the zip-tie landing gear aren't very level so I wonder if that could be an issue.
LG can absolutely ruin your "level" Accelerometer cal. In reality, you're calibrating your prop's attitude in relation to the board, which can be all kinds of off from the skids. Not sure which board/ROM you're using, but there are "in-flight" calibration modes in the *flight ROMs, where you get the craft flying and level hover, then tell the board that that is the "level" attitude. A bit complicated to use, but it's the purest form -- you're actually calibrating the board to the least-drift attitude.

Another thing I was wondering is how much an imbalance makes a difference. In other words, does a multirotor care about CG. It seems like it would but I don't know if it would give me these symptoms.
Care? They do . . . and they don't.

A well tuned board will automatically adjust for CG, but in response it may run one or more motors faster than the others for the same throttle. In this respect, they don't care -- they'll take care of it all for you . . . until they have trouble doing so. Running higher on throttle lowers your higher-throttle margin, and in the end reduces the resolution the board has at it's disposal.

If your CG is WAY off of idea, this could result.

So what is the "ideal"? If you define it as equal RPM for equal throttle (A good goal, IMO), a tri will be along the centerline, somewhere between 1/3-1/4 the way back of the total length from the front motors. if they all pointed directly up, it would be 1/3, but since the tail sacrifices some of it's thrust, vectoring it to create counter-torque on the frame, the point moves forward just a touch . . . just to give that rear motor a slightly longer lever arm. having your front motors counter rotating decreases the tail's average tilt in hover, so the point in that case will be closer to 1/3.

Also, throttle resolution seems to be too touchy. Even with the gentle back pressure I can't keep it from a slightly more than mild ascent or descent.
If you're running a *flight ROM, look into Throttle Midpoint and Expo.

Adjusting Throttle midpoint up and down adjusts needed power out to push "hover" to mid-stick. On absurd T:W airframes, (the ones that leap into the air at the first bump up on the throttle) this is a must to tweak.

Throttle Expo does exactly what you expect -- softening the center. if your hover throttle is twitchy, this can tame it down a bit.

Some thoughts I have for improvement:
The wires and ESC's need to be placed better. As they are ther is some binding where the wires flex entering the body when I fold the booms back and the ESC's don't completely clear the body.
Cleanup is always a reward unto itself ;)

I need better landing gear. I'll get some heavier duty zip-ties and try to install the to keep the body level while on the ground. Another option might be something that could keep this thing floating above the water.
Have any 2" PVC laying around? got a chop-saw handy? 1/2" rings of 2" PVC, zip-tied on, make FANTASTIC LG. Stiff so it doesn't flex or rebound on landing, flexy enough to give-without-breaking on a moderate hit, and cheap/easy enough to source that a broken piece from a hard landing is painlessly replaced. When I make 'em, I do it by the dozen -- setup a stop on the saw, chop, chop, chop, . . . then step over to the bench grinder and cut a quick flat in them to make the mounting easier. A few bucks worth of pipe and about 1/2 hour to make a slew of spares.

An installed centering bubble level might help to ensure the tricopter is level for calibration/initialization purposes. I remember our discussion on another thread about the uselessness of stick trim and while proving everybody right and myself wrong I also saw how placing either my Inductrix or my Nano QX2 on uneven ground for initialization (the time after I plug in the LiPo until the loght stops flashing) messed up take-offs terribly. If this is also true for the tricopter then having a bubble level installed should allow me to control that variable. The other option is to have a board with levels that I could use for all my rotory aircraft.
Here's the thing . . . the *flight and *pilot ROMS only calibrate the accelerometer on command. They calibrate the gyros on power up -- plug the battery in, then set it down to be *STILL* for a few moments -- level is not required. These ROMs remember what "level" is between power cycles, but they must learn what "not spinning" is each time. The BNF quads are a different story. They must go through a full calibration each time since the user doesn't have a good interface to tell the quad "you are now level".

You can always install the bubble level, but as discussed earlier, it's really the props that must be "level" with the board, not the landing skids. setting it on the skids and sighting the bubble only tells us the frame relative to the skids, not the thrust columns.

Cute . . . but not really effective.

I might shorten my booms. Right now they're 12" and I'm thinking of taking them down a few inches. I'm not decided on this and I porbably won't change it until I 'm proficient with the long legs.
Shorter is more agile, longer is more sluggish . . . but keep this in mind of the controller, not just your skills on the sticks. Longer means a commanded correction from the controller will have more slop in it's control as it waits for it's response to impact the change in attitude. Shorter will make her more responsive in your hands . . . but it'll give the controller a bit more agility to clear out errors in the gyro.

you'll see a similar effect in prop length, with the longer props more efficient, but the shorter ones picking up more agility . . . all assuming the different props can generate enough lift without bogging down the motor, naturally.

your build, your call.

It needs a battery tray. I have hobby plywood and can make a tray for the LiPo and a camera, maybe one of those new RunCam3's although the Night Eagle looked interesting too.

Speaking of batterys; what do all of you tricopter types prefer 3S or 4S? I've tried both and either seem fine but that low voltage buzzer seems to be set for 4S. With 3S LiPo's it beeps soon after lift-off. Does anyone know how to adjust the onboard alarm?
Depends on the ROM . . . in the *flight boards, there's a tab just for that. I haven't played with it much since it's moved . . . so pointing vaguely where it is about the most I can do ATM.

3s v. 4S depends on the airframe, but if I gather right that "training" and "tuning" are the current goals, I'd say lean 3S if it's enough.

Bumping up to 4S gives you a different power curve, increasing your ability to dump power into the air, but simultaneously increasing your payload capacity so you can add more battery pack to make up for the faster power drain. Games can be played with swapping voltage capacity and prop size to increase speed or endurance . . . but for now, I'd say stick to the lower voltage until you've got her flying true.

I'm considering different props. Eventually I would like this maneuverable but with endurance. As I understand it fewer
and longer blades can give me more endurance.
Higher quality (stiffer/better airfoil) props of the same size will give you an infinitesimal bump in both . . . but in general, agility and endurance are opposite ends of the spectrum. Again, you can bump up the voltage as you shrink the prop (the prop will naturally need to shrink as voltage rises to stay roughly the same) to increase both agility and maneuverability . . . and then restrain/exaggerate the prop change as you increase your battery voltage/capacity to favor one or the other.

Eventually this must have LED's.
Well that goes without saying ;)

Static color is easy -- buy strips, wire into the battery harness -- but think about how you want to use them. The most effective way I've seen is placing them on the sides of the booms so certain colors are hidden from view from certain angles.

Addressable LEDs . . . a bit harder, but it's a good way to get mode/arm/warning indicators out on the frame.

I'm interested in having prop guards to keep this flying blender in check.
You're trading performance for safety. Your build, so your call, but I'm sure you're aware the most effective safety mechanism exists between your ears.

It may seem like a fair trade of performance for reducing potential harm to others, but you're also making it a touch harder to fly at the same time, making a crash more likely . . . all for a safety measure that has lulled many into relying on it for more than the last-ditch stop-gap it is . . . to the injury of others when they failed.

If you choose this route, I advise: know what you're loosing, and fly it as if they weren't there.

And lastly I would like this to make it an all-weather flyer by water proofing the electronis.
Never used such stuff . . . but never flown in more than a light drizzle. I've only flown in snow once, and that was more to say that I did than anything else. Beyond the stuff Peter used to fly underwater with, hopefully someone else will have more experience.

So there it is. Thoughts? Suggestions?
Sorry, I'm out of ideas ;)
 
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JimCR120

Got Lobstah?
Site Moderator
#34
ok . . . a lot to unpack . . .
Yes, regretfully. I do try to be concise in articulation but often fail.

Lets start with a bit of unhelpful advise...
I doubt any of your advice is unhelpful.

Have you tried flying it in acro? This would eliminate any pitching caused by poorly leveled accelerometers, since they wouldn't come into play. You may also just be that far out of tune :(
Yes, well, maybe not. In the triflight config I saw 3 modes but only employed (horizon and angle) and have been advised that both have stabilization though one with much less. I will re-configure and give this a try.

LG can absolutely ruin your "level" Accelerometer cal. In reality, you're calibrating your prop's attitude in relation to the board, which can be all kinds of off from the skids. Not sure which board/ROM you're using, but there are "in-flight" calibration modes in the *flight ROMs, where you get the craft flying and level hover, then tell the board that that is the "level" attitude. A bit complicated to use, but it's the purest form -- you're actually calibrating the board to the least-drift attitude.
I have the F3FC board from RCEXplorer.se. If there is more information regarding my board I'm not yet educated enough to know what it is.
I suspected having the platform level made a difference as evidenced by my manufactured BNF's. I will play with this more on them using their acro modes to see how I can isolate a poorly leveled accelerometer from the equation.
And of course I will get to work on making some better LG for the tricopter. I like your PVC idea.

So what is the "ideal"? If you define it as equal RPM for equal throttle (A good goal, IMO), a tri will be along the centerline, somewhere between 1/3-1/4 the way back of the total length from the front motors. if they all pointed directly up, it would be 1/3, but since the tail sacrifices some of it's thrust, vectoring it to create counter-torque on the frame, the point moves forward just a touch . . . just to give that rear motor a slightly longer lever arm. having your front motors counter rotating decreases the tail's average tilt in hover, so the point in that case will be closer to 1/3.
I believe I understand the idea of providing leverage for the rear motor. I was thinking of it in another way where actual CG should be near the accellerometer but then moved foward a portion to compensate for the rear motors extra work. Is my thinking here close?

If you're running a *flight ROM, look into Throttle Midpoint and Expo.

Adjusting Throttle midpoint up and down adjusts needed power out to push "hover" to mid-stick. On absurd T:W airframes, (the ones that leap into the air at the first bump up on the throttle) this is a must to tweak.

Throttle Expo does exactly what you expect -- softening the center. if your hover throttle is twitchy, this can tame it down a bit.
I don't understand what you mean by "*flight ROM". There is an inflight tail tune program but I am unaware of anything else. What is a T:W airframe?
I will go back over my throtle midpoint and endpoints. Also of note, maybe connected, when I arm the tricopter the props spin a bit, though nowhere near take-off rpm.

Here's the thing . . . the *flight and *pilot ROMS only calibrate the accelerometer on command. They calibrate the gyros on power up -- plug the battery in, then set it down to be *STILL* for a few moments -- level is not required. These ROMs remember what "level" is between power cycles, but they must learn what "not spinning" is each time. The BNF quads are a different story. They must go through a full calibration each time since the user doesn't have a good interface to tell the quad "you are now level".
Here I get a bit lost between gyro purpose and accelerometer purpose. Aren't they both detecting movements around axes for stabilization? If a level platform aids tricopter and BNF micro quads alike, then how is it a different story?


You can always install the bubble level, but as discussed earlier, it's really the props that must be "level" with the board, not the landing skids. setting it on the skids and sighting the bubble only tells us the frame relative to the skids, not the thrust columns.

Cute . . . but not really effective.
Thrust columns makes sense but that, once done is set and done. The circular bubble level would indicate how level the platform is when it is set down and/or powered up when gyros and accelerometers are doing their thing. If landing gear can mes things up then why not unlevel ground? My thought was if the buble was off slightly then it would be expected that a stabilized multirotor would slightly drift (the truer the levelness the less resulting drift). Is my bubble off center in thinking this way?

3s v. 4S depends on the airframe, but if I gather right that "training" and "tuning" are the current goals, I'd say lean 3S if it's enough.
Very well then, 3S for the time being, as if I didn't already have plenty of variables. I will need to find how to tell the low voltage beeper the news. It seems to think a fully charged 3S is getting low immediately after lift-off. I think it's currently set up for a 4S.

Addressable LEDs . . . a bit harder, but it's a good way to get mode/arm/warning indicators out on the frame.
Cool idea, function and form!

It may seem like a fair trade of performance for reducing potential harm to others, but you're also making it a touch harder to fly at the same time, making a crash more likely . . . all for a safety measure that has lulled many into relying on it for more than the last-ditch stop-gap it is . . . to the injury of others when they failed.

If you choose this route, I advise: know what you're loosing, and fly it as if they weren't there.
I like the advice. I don't plan on flying the tricopter around people anyway. It was more a precaution to preserve the tricopter. Other than some added weight, how is performance hindered?

Sorry, I'm out of ideas ;)
No, I should apologize for exhausting you of all your ideas. Maybe a sarsaparilla at FliteFest will help you recover. Thank you for all the help Dan.
 
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PsyBorg

Wake up! Time to fly!
Mentor
#35
Just a thought on the landing gear.. maybe do what I did on my versacopter and zip tie 200 size heli gear under it. It will stays sqaure to the frame, not flex as much or sag from supporting the weight to far out on the booms and the tiny bit of added weight will be nearer to cog so less stress on the fc. Yes they do break but easily repairable to be more shock absorbent when you rebuild with zip tie "Springs" and packing tape to put them back together.


"I like the advice. I don't plan on flying the tricopter around people anyway. It was more a precaution to preserve the tricopter. Other than some added weight, how is performance hindered?"

I don't think its so much the weight more as where the weight is added. Heavier arms mean more effort to move which means much slower reaction times as well as stress on the motors to do the work to both move AND stop the momentum. Which in turn will probably NOT enhance your tuning experiences.
 

JimCR120

Got Lobstah?
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#36
I don't think its so much the weight more as where the weight is added. Heavier arms mean more effort to move which means much slower reaction times as well as stress on the motors to do the work to both move AND stop the momentum. Which in turn will probably NOT enhance your tuning experiences.
That makes sense. Thanks.
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#37
Yes, well, maybe not. In the triflight config I saw 3 modes but only employed (horizon and angle) and have been advised that both have stabilization though one with much less. I will re-configure and give this a try.
Acro is more the "lack of stabilization" -- it's slang for all stabilization turned off, or "gyro-only". Angle and Horizon are both self-level stabilization modes -- you can only have one on at a time -- angle being stronger with a hard limit to the maximum tilt. Horizon has no such limit and feels more like acro the farther out on the sticks you go. Hard over and horizon will let you flip and roll. let go of the stick and it'll slide back to level.

Not sure what the "third" stabilization mode is . . . Baro? (altitude hold) Mag? (heading lock)

I have the F3FC board from RCEXplorer.se. If there is more information regarding my board I'm not yet educated enough to know what it is.
Fair enough. Not that familiar with that board either, but it's in the *flight family (baseflight, cleanflight, betaflight, triflight . . . ) as opposed to the *pilot family (openpilot, librepilot, dRonin, tauLabs). Most of the features and setup will be the similar among other family members, and between family members, there's more same than there is different . . . but they all do support a few unique options.

I suspected having the platform level made a difference as evidenced by my manufactured BNF's. I will play with this more on them using their acro modes to see how I can isolate a poorly leveled accelerometer from the equation.
And of course I will get to work on making some better LG for the tricopter. I like your PVC idea.


I believe I understand the idea of providing leverage for the rear motor. I was thinking of it in another way where actual CG should be near the accellerometer but then moved foward a portion to compensate for the rear motors extra work. Is my thinking here close?
Accelerometers are affected slightly by the distance from the CG, but it's not that strong of an affect. "Close" will do -- you'll see the impact from an unbalanced motor load long before the accelerometers will be confused. Gyros are immune to being away from the CG, so long as they're kept properly aligned with the axes.

I don't understand what you mean by "*flight ROM". There is an inflight tail tune program but I am unaware of anything else. What is a T:W airframe?
I will go back over my throtle midpoint and endpoints. Also of note, maybe connected, when I arm the tricopter the props spin a bit, though nowhere near take-off rpm.
T:W -> Thrust to Weight ratio . . . I was referring to airframes that have more power than sense ;)

The spin on arm can be one of two things . . . there is an option called "motor_stop", and you may have it turned off, which I don't recommend for tri's. Some disagree with that, I just happen to think they're wrong ;)

The other thing it could be . . . Air Mode. If you have this on, turn it OFF. I'ts a feature that keeps the PID loops correcting the craft while it's on the air and the motors are at idle -- typically the craft is mid-maneuver or descending rapidly, but it keeps the ESCs spun to idle and adjusting slightly to maintain stability.

Neat feature, but one thing to note about it -- it's called "Air Mode", not "Land Mode". If you are on the ground or about to land, it will make the flight controller do stupid things . . . which your controller is doing at the moment. I could see this as causing your current headache.

Here I get a bit lost between gyro purpose and accelerometer purpose. Aren't they both detecting movements around axes for stabilization? If a level platform aids tricopter and BNF micro quads alike, then how is it a different story?
Gyros measure change in attitude, Accelerometers measure change off level. It's trivial to run a gyro cal . . . wait until the numbers stop changing and it's probably still. Most ROMs will run the gyro cal on the initial power up and arm, so if the signal drifts a bit, "0" is tightly defined.

Accelerometers . . . not so much. When they stop changing, is the airframe level? That's a bad assumption. "0" won't change much, but it will drift a bit. The software can dead-band the accelerometer without much impact on the flight, so long as it's got a good measure of "level" to start with. Most BNF airframes take "level" every time, because there's no way the user can tell it to take a snapshot of it. The *flight and *pilot ROMs take that snapshot during their setup, and it likely won't change enough to need to be run again.

The point is, "still" is easy to measure, so it's cal'ed often, but "level" is hard, so it's only cal'ed as often as it has to be.

Thrust columns makes sense but that, once done is set and done. The circular bubble level would indicate how level the platform is when it is set down and/or powered up when gyros and accelerometers are doing their thing. If landing gear can mes things up then why not unlevel ground? My thought was if the buble was off slightly then it would be expected that a stabilized multirotor would slightly drift (the truer the levelness the less resulting drift). Is my bubble off center in thinking this way?
Already covered accel cal . . . it might be helpful on the initial cal, assuming everything is square to everything else . . . which may be a bad assumption . . . and won't be that handy after you get a good cal.

I like the advice. I don't plan on flying the tricopter around people anyway. It was more a precaution to preserve the tricopter. Other than some added weight, how is performance hindered?
Increasing your pitch/roll moment will impact your performance, but so will anything anything in your thrust column . . . like supports for prop guards (above or below). Since your thrust columns isn't merely your thrust but your control surfaces as well, it can have an impact on how well it flies. It will also become an additional source of "prop thump" -- vibration from the props moving air across booms and other obstructions. It all adds in to the general vibration noise on the frame.

I'm not saying they will become uncontrollable, just that you sacrifice some control when you add them on. Some airframes you'll never miss it. Some you need all the slop taken out that you can.
 

JimCR120

Got Lobstah?
Site Moderator
#38
Well now I have some work to do with this. I'll be posting back here on the progress. Thank you for the detailed explanations and guidance.
 

JimCR120

Got Lobstah?
Site Moderator
#39
First Public Flight

Ok so I apologize.:rolleyes: You didn't get to see the maiden (unless you want to count those few seconds in the basement). However I am getting more of a feel for it and about ready to tear it down and re-build it with some tweaks. Just so you don't think I don't care I did do some firsts in this video... doubles (rolls and flips). I'm new at this so to me it's a big deal. By all means if you see or hear something that should be address, let me know.

And if you're wondering who and how the video was captured, wonder no more; I was piloting and recording via...

... a camera strapped to my head.:eek:
Screen Shot 2017-04-04 at 12.47.14 AM.png
 

PsyBorg

Wake up! Time to fly!
Mentor
#40
Not a bad flight at all. You looked like you knew what you was doing even. That flys nice and stable. AS smooth as that all looked with the yaw spins I was surprised you went way out and did not turn and come back but merely backed it up to you in the same orientation it left. You aren't skeered of a little nose in flight are ye? :p

Nice job on build set up and maiden.