Psyborgs Gremlin Build Setup and Review

[BEEMANS]

I am using this camera currently. . It was 16.99 when I bought it originally(after a few days of flying I prefer the wire mounted antenna to the hard mount of the hyperion. I have the Bixler frame and since it puts the camera out front with no protection I have two ideals on how to deal with this. First I am going to make a couple of roll bars out of black wire ties to go over the camera. Second I saw a Youtube video that shows how to detach the Vx boards from the camera board I have two camera combos that are bad but I don't think both parts are shot on them. So my final attempt with the camera situation is to split the boards and mount the Vx board flat on the top of the quad and install a whip antenna. I am looking for the most crash worthy setup I can think of and if I am guessing correctly the weakest link in the Gremlin is the camera setup. I dunked the whole quad in a dog bowl on my second flight and I am still flying (so I am not too worried about the quad setup). The original Hyperion camera is anther story and I think the camera from it is still good but the Vx board has a glitch (the antenna took a good hit and I cannot figure out what is wrong).

 

[PsyBorg]

More then likely you cracked that pcb riser section the mount the antenna too and the traces are broken. That is such a poor design its not funny. I think they thought people would buy another if that broke.. I certainly will not after the nightmare I had with mine. I am about to go out for another test on mine. I moved the receiver antenna down to a horizontal position out of the line for the vtx antenna to see what that gets me. Will have video later to show the success or yet another failure.

 

[hungryzebra]

I'm using this one: https://www.amazon.com/gp/product/B06XB2ZRBP/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

I'm really liking the coax connection instead of the PCB mount. And it has selectable power output. I was finding the 25mw a little weak for my taste on the hyperion camera. The 25mw on this one works quite well, but I leave it in 50mw for a bit of extra insurance when ducking around obstacles in my back yard. I haven't tried the 200mw setting and probably wont, I'm SURE the battery life will suffer and I don't need all that.

 

[BEEMANS]

Last night...
I tried my ideal with the black wire ties. It works great if you can find some wire ties wide enough to drill a hole in them you can mount them under the frame screws and hot glue them to the front where the two square holes are in the Bixler frame. Then just make the arches long enough to form over the antenna and miss the props. The quad will sit on the wire ties when upside down. The antenna will still take a hit if you hit hard enough but I haven't been bending the clover leaf as much.

 

[PsyBorg]

Ok updates

Variable power 25/200/600 mw vtx, run cam mini yes I know they are a tad big for a Gremlin but I wanna see darn it!! Besides this will all go into my next project in time once I gather parts. I am shooting for a 100+ mph racer. Got a Gens ace 3s 450 mah 25c battery to try and see if they are viable replacements for the heavy 800 mah 20c I been flying. (Bills Law struck and I killed my last female jst connector so I had to adapt and use a few of the bullet connectors of esc's I had laying around to wire power)

This all dropped AUW from 180 g+ to under 158 g. I will need to re-tune and set the camera up but I want to wait til I have another action camera so I can make how to videos for the forum as people have been askin me to give em a shot.

This flight was late in the evening as the sun was setting hence after the first crash I was flying LOS. It got dark in the shadows fast. Anyway I have a flyable Gremlin I can actually see with now so things can progress normally now. I will post again another day with final specs on all the gear used, the pids I fly on for 3s acro outside and 2s indoor with Horizon mode as well as all the camera settings.

For now I give you this to start the ball rolling in a good direction.

EDIT: Oh yeah.. I still have the dead spots around that play set so I will see what flying on 200 mw does to make it better or worse so close to the buildings and a bunch of antennas.

 

[striker8]

Just got to say thank you PsyBorg you are the man!

Life cropped up and it took forever to find time, but after a month I finally had a chance to try your pid's in my gremlin and boy they made a difference. Before the thing was almost uncontrollable, now it's stable and I can almost fly it like it should be.

I don't think with my level of knowledge or skill that I would of persevered tuning things to this level and probably just gave up.

PsyBorg, you are a gentleman and a scholar and your documenting things like you did is greatly appreciated.

 

[PsyBorg]

HEY!!! no need for name calling!!! gentlemen HA!!!

Thanks Striker8. I am really glad all the frustration I went thru was able to help someone. Seeing you say thank you in public made it all worth while. That is what we do here though so as you learn pass your knowledge forward to someone else who needs the help and that will make it even more worth the efforts when I get to see you doing the same thing we all try to do here.

Good luck, happy flying, post up some pics or videos of what you ave accomplished as we all enjoy them specially the successful things.

 

[PsyBorg]

Ok so now I have had several people pm me for my pids. Rather then type out what I use and add the explanations about certain things a bunch of times here they are.

First and foremost is that rates are the most important thing in tuning. Specially in Beta Flight as there is such fine changes that you can have a very flyable quad with pitch and roll pids ranging anywhere from 35 to 70+ on the same quad and only notice a slight change within that range.

For those of you who want to run 3s do NOT run stock betaflight pids on the Gremlins. The motors heat up horribly and the esc's get over worked. Do short easy flights and tune your quads. The closer to a good tune you get the less heat you produce and the less chance of damaging your gear or burning out esc's. That said the manufacturer I am told does NOT rate these 6 amp esc's for 3s so use 3s and any of my settings at your own risk.

First we start with the rates I use on all of my quads using beta flight.

RC rate for pitch and roll is .7 and .87 super rates. This gives a 937 degree per second maximum I use now a .20 Expo on them for thr Gremlin. Its a touch higher then I normally run but I am tuning for indoor and out door flights using 2s indoor and both 2s and 3s outdoors.

For Yaw I use RC rate of 2.05 and a super rate of .45 which gives a max yaw of 992 degrees per second. This is FAST but the smoothness you get with that mix specially for fast tight turns has a great secure feeling to it. I use zero expo on yaw but if you are not used to that fast a yaw go ahead and hit it with .10 expo max other wise you will start over compensating in those hard fast turns.

DISCLAIMER: Pids will be different for every quad out there and a lot of what feels locked in is perspective of the pilot and how you fly. These pids were done when my quad weighed 180 grams. It now fly's at 159 grams and is just fine on them although I do want to re-tune for the lighter weight.

Axis proportional Integral Derivitive
Roll 60 27 23
Pitch 55 27 23
Yaw 55 30


As stated earlier I have also been working on the auto level settings for indoor flight. This is what I have come up with so far.

I left Angle mode alone as all you can adjust is the strength and stock is 50. I NEVER use angle mode only horizon and acro.
I set Horizon like this for indoor.... Strength is set to 30 transition to 20 but I think I will drop that to 18 so it won't lurch back to level so brutally as it does stock.

Angle limit I set to 10 and sensitivity to 25


One final tweak I have done is to change the Throttle mid position to 63%. If you are new to flying and the Gremlin is your first quad ignore this part. If you fly bigger race or free style quads you probably have issues catching the Gremlin after flips and rolls. This is because the bigger quads are stronger in low throttle ranges and can catch the weight. You have built muscle memory for this as I have and tend to go to light on the throttle where you normally end up. Changing the center to ~60% will let you keep using that muscle memory yet still catch the quad like you are used to.

Last I set TPA to .35 at 1500 start point.


I hope this helps you to fly smoother and enjoy the Gremlins as they are a blast. Just keep in mind these are what I like to use and it suits my style of flying and my build weight nicely. These may or may not make your experience better. I do highly suggest that you put these on profile two or three so you can switch back to what you already have should these not work out. The stick commands to change profiles when in the field are Throttle low left for all three and Roll left is profile one, pitch forward is profile two, and Roll right is profile three. These are done in an unarmed state and can be changed at will while un armed. Just look at the lights on the FC and it will blink accord to each selection.

Have fun as always and any feed back or questions are always welcome

 

[BEEMANS]

Psyborg
Have you seen these mini cam/tx combo's


https://www.amazon.com/GOQOTOMO-GT0...qid=1499449032&sr=8-1&keywords=25/50/200MW+tx

Have not tried it but I wanted the 50mW setting for around the house.

 

[nevenelestate]

Psyborg
Have you seen these mini cam/tx combo's


https://www.amazon.com/GOQOTOMO-GT0...qid=1499449032&sr=8-1&keywords=25/50/200MW+tx

Have not tried it but I wanted the 50mW setting for around the house.

That is the camera, or very similar to the one that I am using on my Gremlin (http://a.co/7cfo3uH) I did a few flights on 20mw and then decided to bring it down to 50mw to save some battery.

 

[PsyBorg]

yeah I have research a bunch of them AIO's and the all seem to have the same flaw. That stupid pcb riser to support the antenna. You can build cages for the cp antennas and protect them but and head on strike to teh camera and you can kiss the entire setup good by.

 

[PsyBorg]

Got up early this morning and decided to go rip the Gremlin. Took my old Cannon camera out and made a short comparison video with the settings I worked out on 2s and 3s to show how nice these can fly both indoor and out. the Horizon settings I have now are really smooth specially if you take time to make sure the femto boots as close to level as possible and that battery placement is good for cog. I just tossed the batteries on for these flights so it does not hover perfect so I could show how smooth the settings are where auto level does not fight you for control.

With the Gremlin so small and no one up to film for me I could not do the full speed runs I wanted to show where you can fly this thing on 3s at 98 degree tilt and run flat out across a football field in VERY short time. Anyway I have been telling people about these settings so time to show them in flight. Bare bones Gremlin build on the Josh B delrin frame. I inverted the rear motors to get the props more in line and I am using 2s and 3s gens ace 450 mah 25 c batteries now. At some point I ill have a permanent
FPV system for this as I keep stealing it for other projects hehe.

 

[Michael9865]

Looks good. Not as angry sounding on a 3S as I thought it might.

 

[PsyBorg]

Well the 2s part of this was around 50% throttle. The 3s was less then 1/3 for the same speeds around that little area. When you hit the throttle on 3s it screams. They can be quite loud when zippin around with those square props.

 

[PsyBorg]

Well I killed mine today. I was out back when one of the tenants kids came back to watch and was eggin me on to do crazy things with it.. So Naturally I did!

Well I launched it to the moon nearly out of sight since I have no video on it currently. Did a bunch of flips on the way down and did not catch it properly. It landed square on the back left motor and made the blade cut into the heat shrink on the esc. Now that motor won't spin. Not sure what I did but I will grab the meter and check things out after dinner. I ordered a new esc and some more props anyway and since I will be doing surgery I think it is time to move over to the carbon frame since this one has a crack in one of the arms begging to be snapped off.

I had it over the past week end at my friends house for his B Day party and let his son fly it around. He was bouncin it off trees, bushes, the house... He eve somehow managed to get it out in the street and was grinding it upside down when he panicked and hit the throttle then frantically started flipping switches to dis arm it because he forgot which it was. He only managed to grind a chunk out of one prop thru all that some how. These things are amazingly resilient.

Anyway here are the current settings for a bare bones no video Josh B frame build. Including the soft Horizon mode settings and the throttle center change to compensate the power band to catch it better coming off flips and rolls. You may not want the pids but the rates and the Horizon mode settings make this great for indoor or out on both 2s and 3s on stock components.

 

[Michael9865]

Darn kids always creating problems, LOL. Thanks for the updated settings.

 

[PsyBorg]

You are welcome Michael. I think between the rates and the Horizon settings you will find this fun to fly in smaller areas specially since the auto level will not fight you now using them. Keep in mind that tune is for a bare bones setup with zero video on it so the added weight may make yours work differently. I will be testing the set point weights and transitions next once I replace the esc and get back in the air. Hopefully make it even smoother. Just keep an eye on temps the first few flights as each one is different with all the various frames and build styles / materials.

 

[PsyBorg]

Got around to per surgery check ups on the Gremlin. As I thought the prop strike removed some components. I was surprised to find how ever the other rear motor had a cap knocked off as well but still worked. I only ordered one esc so I will have to try and resolder the one cap on the still working esc. The new one should be here in the next hour or so so I will know more later after it cools off a bit and I can lean forward to solder without dripping sweat on everything.

One side has the cap missing and luckily that stayed in the heat shrink. The other has the same cap missing but also lost a transistor or regulator of some kind. This is what it all looks like currently.

 

[PsyBorg]

Got time to sit down and rebuild the Gremlin onto the Carbon fiber frame since the original has a cracked arm and I killed an esc and damaged a second one last time I flew.

I did my standard beveling of the edges of the carbon then the red paint after it was all cleaned. The carbon looks good for the Gremlin. I think they got a great deal for who did the carbon work. Anyways I fixed the one esc by putting the capacitor back on that luckily stayed in the heat shrink after it was knocked off. The other one however I was not so lucky as I lots a cap and a transistor or regulator which ever that particular component was. Replaced that one out right. Remounted everything to the new frame. Flashed the new esc to 16.6 as it came with 16.5. Did the motor calibration and then did a quick test to make sure motors were spinning the correct way.

Will go out and remaiden it as soon as the batteries finish charging. The 2s just dinged as I was typing so wont be long for the 3s to charge and I will go make sure everything is properly working. Then at some point I will pick up yet another Runcam micro and a small vtx since my other ones don't seem to want to play nice or are way to heavy.

Here is what it looks like now without FPV and one shot with the micro sitting on the pad and not even mounted.













Jim my offer still stands since I see you have not been able to move forward on yours mate. All ya gotta do is let me know.

 

[PsyBorg]

Been out rompin on the new frame and set up fine tuning it again. Seems the carbon frame has a totally different resonance structure and makes a huge difference in how a tune effects it. It also seemed to make it a lot stronger in the rates area so that makes me wonder if these little motors are actually strong enough on 3 s to be flexing the arms of the Delrin frames and kind of acting as a passive soft mounting.

I dropped the pids back a bit from that aggressive tune I did for Frolic to help him get better situated. I also refined the auto level settings for Horizon mode a bit more. So now I am left with fine tweaks on the pids and redoing TPA to get rid of the last little bit of full throttle chatter. Not sure at this point if thats tune or prop issues that wont be cured without spending time balancing them better from out of the box.