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Simplecopter Mini Tricopter vs Mini Quad Discussion

kah00na

Senior Member
#1
450 & 550 tricopters were real popular even when people were building similar sized quadcopters. Now all the rage seems to be about miniquads. Why aren't mini tricopters like Matt Hall's mini tricopter catching on? He's using SunnySky's with 6045 propellers and it seems to be able to lift a lot of weight. Could it be because people think it won't carry as much as a miniquad? Could it be because of the yaw servo? People are more familiar with quadcopters than tricopters? Is it because David Wi... is back in Sweden now?

I'm basing this "unpopularity" opinion based on that I've only seen 2 simplecopter mini tricopter videos on YouTube and the simplecopter's addict thread on rcgroups is pretty inactive. I bought one of the mini tricopters along with the recommended motors and ESCs and I'm anxious for the parts to arrive so I can get it flying so I can give a more personal experience opinion after flying them both.

What are your thoughts?
 

jhitesma

Some guy in the desert
Mentor
#2
I think one of the big appeals of the mini's is how resilient they are to crashes. Yeah, you may go through quite a few props - but on a well designed setup that's the bulk of what you'll be breaking in most crashes.

With a tri you've got that servo. That servo is what keeps scaring me off from trying a tri. Building a tilt that would be accurate enough is something I know I'd mess up - but I've yet to see one on the market that's small and light enough for a mini and which would hold up to me. And all these people having servo issues on larger tri's even with good servos...I can afford to keep replacing props but servos and mounts are expensive.
 

califrag

Senior Member
#3
I noticed the same thing as kah00na when I started researching mini-tricopters for my current build off DW's frame.

It was no problem finding information for tuning mini-quads and mini-hexes, but there just wasn't much out there regarding mini-tris.

The best that I could make of it all was 'they are too susceptible to oscillation, too hard to tune, so go with a quad and get flying instead'.

Well, I really like flying my big tricopter so naturally, I had to build the mini version regardless.

I can definitely understand the servo concerns, right now I've got a pretty cheap $6 servo for mine, I'll see how that holds up.

Also having the same issue on my build with the tilt mechanism being too heavy and trying to figure another solution now.
 

kah00na

Senior Member
#4
Well, I built a simplecopter mini tricopter yesterday and compared it against the FPV250 in this video. I want to get FPV gear loaded on it and see how it flies with the extra weight from the FPV gear. I have a ZMR250 I'm trying to get finished with FPV gear on it. Once I get it finished and tested out, I'll probably move it over to the mini tricopter.


If you have any agreeing or opposing views with anything I said in the video, I'd like to hear them!
 
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kah00na

Senior Member
#5
Today I flew with a 2100 mAh 3S battery, instead of my normal 1500 mAh, and I was able to squeeze out 13 minutes of flight time. It started beeping pretty bad (low voltage alarm) for the last 8 seconds, but it completed 13 full minutes. I was flying around LOS pretty conservatively. That is the longest flight I think I've ever had with any of my multirotors.
 

Cyberdactyl

Misfit Multirotor Monkey
#6
Nice comprehensive comparison. :)

The only couple technical things I would say, so people watching don't get the wrong idea how quads yaw, is at 3:21. The opposing motors create an unequal torque which creates the rotation. The quad does experience centrifugal force, but that is a result, not the method.

Also, with a bit of patient tuning, you can get KK2's to not pop up on hard yaw, at least with Steveis firmware, but with some frames it's harder to tune out than others. From my experience, it takes more tweaking to eliminate with larger frames.

Otherwise, great job and good idea creating a thread to compare the two. :cool:
 

FinalGlideAus

terrorizing squirrels
#7
Well, I built a simplecopter mini tricopter yesterday and compared it against the FPV250 in this video. I want to get FPV gear loaded on it and see how it flies with the extra weight from the FPV gear. I have a ZMR250 I'm trying to get finished with FPV gear on it. Once I get it finished and tested out, I'll probably move it over to the mini tricopter.


If you have any agreeing or opposing views with anything I said in the video, I'd like to hear them!
Not sure how I missed this post until now.

On the subject of Yaw there are two things that really much a HUGE difference on a mini quad. I always thought the tri had much better yaw until I learned how to tune a mini quad. The default PID's on the Naze are WAY too high on Yaw and need to be lowered. Try Yaw P at around 5.0-6.0 for a start and bring down the I gain a fair way. I have found most people don't know how to tune yaw because with P gains they are looking for oscillations and this doesn't happen with Yaw P. All that happens is the yaw gets more sluggish the higher you go and the quad starts ballooning as you have mentioned. The other thing that makes a HUGE difference is Regenerative braking on the esc's. BLHeli FW looks to be producing quite good results now so KISS esc's aren't the only option although how well the regen braking works depends more on the esc hardware.

Yaw was the only thing that I beleived the tri had over a quad but now that's not even the case anymore.
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#8
I agree with FGA. Yaw and 'swooshy' flight is why I have a tricopter. Now that I know how to tune a quad, that difference is gone.

Tricopters are more maintenance, more money, less efficient and less flight time (due to the maintenance) than a similar quad. The tail pivot mechanism and servo weigh as much if not more than the 4th motor on a quad without providing any thrust. The tail pivot mechanism requires more maintenance than a 4th motor. They are a constant maintenance issue if you fly over sand and I mean EVERY flight maintenance.

The pivot mechanisms are notorious for breaking in a crash where the copter 'landed' on the tail boom (common since the servo and pivot tend to make the tail boom heavy) and seem to be the weakest part on the whole copter. They also cost the most in time or cash to repair/replace.

If someone comes up with a solution to the tail pivot that doesn't outweigh a motor and won't break in a minor crash or seize with a little grit kicked up by a rotor, I will consider one.

Until then, we have mini-quads and hexes.
 
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Cyberdactyl

Misfit Multirotor Monkey
#9
One thing I like about tri's is they they are much easier to recognize orientation. I can LOS fly my tri out 500 feet and at a 45 degree angle, or 600 feet straight up, something I wouldn't dream of doing with even a larger size quad. Once you get past ~300 feet, colored booms and props lose any orientation significance for me. Even colored LEDs become one mixed color. However, even the slight asymmetric shape of the 'Y', I can see at distance.
 

kah00na

Senior Member
#11
Your arguments seem to be some of the standard arguments I've read before.

I agree with FGA. Yaw and 'swooshy' flight is why I have a tricopter. Now that I know how to tune a quad, that difference is gone.

Tricopters are more maintenance, more money, less efficient and less flight time (due to the maintenance) than a similar quad. The tail pivot mechanism and servo weigh as much if not more than the 4th motor on a quad without providing any thrust. The tail pivot mechanism requires more maintenance than a 4th motor. They are a constant maintenance issue if you fly over sand and I mean EVERY flight maintenance.
The servos I use are 16 grams. The SunnySky motors weight 23 grams. A sheetrock screw adds another 5 grams maybe?
Tricopters have one less motor and ESC which can save your initial budget around $25. Servos are $6.99 and a SunnySky motor is $18.50. Your ESC will be around the $8 price. Tri's also use 25% less propellers.
I have broken 4 servos but I've also gone through 3 motors over the last year.
The tail pivot mechanism can be as complex as you make it. Use a sheetrock screw and you adjust it with a screw driver. Not much complexity there.
Most of the sand in Kansas is in sandboxes. Who wants to fly over kids? ;)


The pivot mechanisms are notorious for breaking in a crash where the copter 'landed' on the tail boom (common since the servo and pivot tend to make the tail boom heavy) and seem to be the weakest part on the whole copter. They also cost the most in time or cash to repair/replace.
When you make your initial rear platform, just make a second while you're at it. It will require another piece of wood and an extra screw. If you replace your servo with an identical one, it is faster to replace than a motor and does not require any soldering. If you're buying the HS-81 or HS-82MG, you are spending money needlessly (I use to buy these). The only thing special about those servos is how proud Hi-Tech is of them with their $30 price tags. Dumb... I have 2 broken ones sitting around - You can see me break one in this video at 1:30 and see it move freely with broken gears at 1:49. Get this servo for $6.99. It has metal gears and is digital.

If someone comes up with a solution to the tail pivot that doesn't outweigh a motor and won't break in a minor crash or seize with a little grit kicked up by a rotor. I will consider one.

Until then, we have mini-quads and hexes.
I've never had one stop working because of something getting inside of it, that is an argument I haven't heard before.

Perhaps the biggest difference between our experiences resides in the frame itself. The tricopters I've built are all made of wood and based off HallStudio's (simplecopter.com) design. When an arm breaks, it costs $3 for a piece of wood which can be purchased at any hardware store and from it you can make 3 more arms. The rear swivel is a wooden platform for the motor with a sheetrock screw through it into the end of the arm. The landing skid is plastic and held on with 2 screws or pieces of wood attached to each arm. If you crash hard enough to break the main plate, you will have a little more time in replacing it - that did happen to me once where it fell from a failed flip in this video, you can hear a crunch right at 8:39 when I straighten the front arm. It took me a while to figure it out what was broken. I'd guess.... only guessing here.... that you were using a fancier frame than my $8-built-at-home-frame. The rear servo is what I think scares a lot of people off. If it does, it should scare them off for the "complexity" it adds rather than frailty or cost. It sure isn't a stationary motor screwed in place.
 
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