gremlin : options and differences and education

[[cy0t]]

Hello ft forums people!

As mentioned in my intro thread ::here::, I'm ready to get flying. However, I've got a couple questions about gear compatibility and options.

Setting the stage:
I've kind of latched onto the ::FTGremlin:: and am clicking through the options. I'm aware this is probably a little more power than I need for the first time up but, with simulator time, motivation, not being shy with the expo, and support of my friends, I'm prepared for the learning curve.

Questions:
1. I've already got a spectrum dx6i (a few years old now). Would like to confirm my understanding the FrSky and Spektrum tx/rx are not cross compatible and the "DSMX Quad Race Serial Receiver with Diversity" is the correct receiver option for me.
a. I'm completely lost with the Hyperion receiver option. Being DSMX, is it also compatible with spectrum transmitter and is there an advantage/disadvantage between the two?
2. Regarding the camera options. FX900TW Camera, VTX with Dipole or RHCP antennas. I am unsure what the difference is between the two.
a. Additional info : I've already got some fatshark gottles (also a few years old now) as part of a combo deal. Mounted the camera and transmitter to an rc car and am having a great time, but don't really know what I have. Does the antenna on the goggles make any difference to compatibility/quality with the antennas on the quad/vehicle?
3. Frame : Not really a question but, at this scale and my current skill level, my inexperienced logic tells me the frame is kind of a vessel for keeping the electronics pointed in the same direction. That said, I'm curious if there is any real reason to chose one FTGremlin frame over another, or if any of y'all have an opinion on it (no is an ok answer ).

Thanks in advance for the education.

[cy0t]

 

[PsyBorg]

Gremlins are a blast to fly but the physical assembly can be a challenge for new builders unless you have respectable soldering skills already. The Flight controller is S.M. ALL. Frame choice is a factor for these not so much as looks or flight characteristics but in compactness and how to mount the cameras if you don't mind seeing the props or do not want to see the props.

Personally after getting the original Hyperion camera and vtx for mine I will not use their products on anything I build. Just way to cheaply made and the design and quality was extremely poor for what I need to fly properly. For mine I have finally settled on the Runcam swift 2 Micro camera and the Eachine Vtx03 variable power transmitter. (Much heavier over all but the Gremlin does not think twice about it. I have flown one at 187 g all up weight and it was still ripping up the sky.) This runs a dipole and works perfectly for the range you will most likely be flying the Gremlin in. Also unless you build a cage to protect the CP antennas on a Gremlin they will get hammered and become useless fairly quickly. If you are anything like the rest of us you will be throwing this thing around like a mad man once you get used to flying it. For larger quads matched circular polarized antennas work better. I use the Aomway cheapie ones as they have great average performance and I tend to kill several on the quad each year running gates.

Most VTX are standard 32 or 40 channel ones and will match right up to any Fatshark product as they have a dedicated band they use and most of the manufacturers set that up in their transmitters as standard.

I have a super long build thread documenting all the things I have done and tried with mine so feel free to look thru that for more ideas and info on various gear and set ups for different flying styles.

 

[[cy0t]]

Thanks for the data brotha. That was super helpful.

I've got a quality soldering station and paint Warhammer/D&D minis for my nieces, nephews and occasionally myself. May have to lay off the caffeine for a couple weeks, but I'm pretty comfortable in a small space.

I dig the build thread. We'll see if I do something similar or if I get excited and skip the documentation as I typically do with my projects.

[cy0t]

 

[NewLn]

The right frame

I have some suggestions regarding the frame. I just picked up the new Alex frame because I thought it looked great and didn't have any props in the camera view. However, once I started trying to fit the FC with the ESCs onto it, I ran into problems. It is a TIGHT fit. The wires from the ESC almost immediately run into the 4 inner standoffs. It is bending the wires and akward angles, and I am probably going to have to resoldered the wires in a way that they are comfortable with. I don't know how the other frames fit, but I would probably recommend TJ's frame.

 

[PsyBorg]

That is one of the reasons that flight controllers went to a thru hole design. You could stand the wires up and put a strain relief loop in them so they are not hard pressed and rub on stand offs nor keep the fc so tightly locked in place that soft mounting it has no effect.

You can see in this pic that I have mine soldered thru hole so they rise straight up and then a soft loop out to the Esc's. Granted I did use taller stand offs on my build so I could flip the rear motors over to get the props in a better line. Its all a matter of planning and looking ahead when you custom fit things into tiny spaces.

 

[LitterBug]

I have one of TJ's frames and it is an even tighter fit. Just picked up an Alex frame and was going to use a 4in1 or alternate ESCs.

This is my TJ's frame build with slack left on intentionally in case I moved it all over to a different frame:


I have a handful of other small ESCs to try which should fit better:


I have everything stashed in the corner for the Alex build, and can't remember if I stuck a 4in1 in the pile or not. Going to use an OmnibusF3 with OSD built in, and think I went with LittleBee 6A individual ESCs. I'll have to post a pick of the two frames next to each other later tonight.

Cheers!
LitterBug

 

[[cy0t]]

So many experiences, input and things to think about. I appreciate your data.

[cy0t]

 

[NewLn]

That is one of the reasons that flight controllers went to a thru hole design. You could stand the wires up and put a strain relief loop in them so they are not hard pressed and rub on stand offs nor keep the fc so tightly locked in place that soft mounting it has no effect.

You can see in this pic that I have mine soldered thru hole so they rise straight up and then a soft loop out to the Esc's. Granted I did use taller stand offs on my build so I could flip the rear motors over to get the props in a better line. Its all a matter of planning and looking ahead when you custom fit things into tiny spaces.

View attachment 98071

Thanks Psyborg, my soldering skills aren't great but I will see what I can do to get the wires to stand up. I'll try soldering tonight and checking in tomorrow. Also I might just remove the inner standoffs to make more room. Would that create any durability issues?

 

[LitterBug]

For what it's worth... Here are my to FT frames. Alex on Left, JT on right:


Alex's frame is better suited for the Gremlin power/FC package. The arms are longer and fit the EMAX ESCs better. You can easily leave the center 4 standoffs off of Alex's frame since they are more cosmetic than functional. I will have to do that when using a 20x20 Omnibus F3 Nano V2 FC. Will be drilling the base plate and mounting the FC with 5mm rubber isolators. The Omnibus F3 has OSD, and I'll be using a 25mw VTX Camera setup that is split.


Think this second FT Gremlin build is going to turn out really nice. Can't wait to get it built.

Cheers!
LitterBug

 

[[cy0t]]

Ordered up. Now the hardest part, waiting...

Thanks again for the info!

[cy0t]

 

[LitterBug]

FYI, I've about given up on the cloverleaf VTXes on these micro builds. They get destroyed too easily. Been using the dipole antennas for the last month or so and have had decent results.

LB

 

[med4life]

hey guys really fast but what kind of motor's other then 5250 can you put on FT Gremlin Frame

thanks and cheers

 

[PsyBorg]

I think you can mount anything from 1104 to 1106 with various KV ratings on them without modding holes. Power requirements will change with motor changes so keep that in mind when you plan your build. If you are asking about specific motors, people are putting the new mini red bottoms on making it 4s compatible with proper esc's to power them. You can mod these anyway you wish which is the whole point of the Gremlin. People can design and build as they wish with the Gremlin itself being just a base model to start from and inspire ideas.

 

[thenated0g]

i want to replace my gremlin plastic standoffs with metal. Anybody know what size i need?

 

[PsyBorg]

TJ and Alex frames use 20mm standoffs. Josh B frame uses 10 mm standoffs. I modded my Josh B frame with the anodized aluminum ones they sell in the FT store and used the aluminum screws I had from other bigger builds. That way I got the FC the VTX and the receiver inside the plates and safe. That also let me get the props more in line once I underslung the rears. That protects the motors and props quite well too!

I also agree with LB about not using CP antennas on these and just go with dipoles. Was even thinking of mounting the cube hd cam I have on mine for a few seconds. Then decided I would rather rip gates with it and not slow down or have to retune for the weight of the camera.