Cube FPV

GepRC Smart35 Frame Review

The GepRC Smart35 is a 3.5 inch freestyle frame which gives you options. 
My review of this frame is based on my own experience from building and flying this airframe. In summary, it is probably the best all-round 3.5 inch frame on the market today. The frame is very robust and the kit comes with an array of fittings. It also features multiple mounting options for stacks of various sizes with the possibility of also have a dual stack mount side by side or top to bottom.  

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GepRC has not skimped when it comes to strength on reliability for this frame, having a 4 mm thick all in one baseplate, as well as 2 mm side and top plates. Now while we would cringe at an all-in-one baseplate for even a 4 inch, on a 3.5 inch frame the all-in-one baseplate is sufficiently strong enough.

The reason many frames in this category have all in baseplates is to maximise the vertical internal space within the frame. Frames which have separate arms, will often have reduced vertical space within the frame for stack mounting. That’s okay with a larger 4 or 5 inch frame where they have room for dual stack mounts, but not optimal for a 3 or 3.5 inch frame. That said, the GepRC Smart35 also affords you the option of mounting dual stacks in the same way that larger frames do – more on that below. 


This airframe kit has a number of extra inclusions above and beyond what you would expect. There are eight stack mount dampeners and 4 spacer dampeners. These are always included when you buy a flight controller, but it’s great that they thought to throw in some extras – they never go astray. The included battery strap is also great quality. 

All stack mount hardware is M2 (2 mm) and it’s great to see that GepRc has included stack mounting bolts in three different lengths and not only that but these have the more reliable square heads instead of cap heads. As well as this, there is an array of smaller M2 bolts for stand-off mounting as well as motor mounting. They even supply longer bolts for motor mounting if you choose to attach the additional arm supports. 

One disappointing inclusion is the battery mount. It’s way too small to be useful in any way and is also made from thin hard rubber. I replaced this with some quality Ummagawd battery mount rubber. Other inclusions which I would put on  the not needed list are the rubber feet to attach under the arms as well as the plastic wire guides for protecting the motor wires, but I guess it’s good that they included them anyway. 


With this frame, GepRc have really thought about the fit-out options. The frame has 26.5 x 26.5 mount holes for whoop boards, as well as both single and dual 20 x 20 mounts. 

The central 20 x 20 mount is perfect for either an ESC / FC stack or an all-in-one board. They’ve even thought to move the centre standoffs forward enough to fit an AIO board with a 20 x 20 mounting pattern. So many frames crowed this central area, with two sets of frame stand-offs limiting you to an ESC / FC stack.

The GepRc Smart 35 also allows you to mount two 20 x 20 stacks – one front and one rear, if you desire. In this way, you could mount your ESC / FC stack to the front and an air unit light to the rear. 

Another unique feature is the 20 x 20 mounting pattern on the top plate. This allows you to mount a 20 x 20 AIO FC on the base frame and then have your VTX mounted on the top plate. Particularly useful if you have 26.5 x 26.5 mount pattern whoop AIO FC mounted on the base. In this case you can simply mount a 20 x 20 VTX above hanging down from the top plate.


The inclusion of the additional strengthening arms for both front and rear may be a good idea. I really appreciate it when a company gives me the option instead of just building them into the frame. So if you need more strength, you can add these additional arms. Beware however that adding these additional arms will literally turn your quad into a tree magnet. They create four gaps which make your frame perfect for hanging on twigs and branches of any tree you may run into. So you really need to ask the question “what sort of pilot are you?” Do you tend to crash into the ground a lot – then use the additional arms. If you however seem to be attached to trees, it may be best to leave them off. Personally, I feel that the baseplate and arms are strong enough without the addition of these extra arms.


Once again, here we are given options with the motor mount slots accepting both 9 mm mount pattern as well as 12mm mount pattern. You wouldn’t think this is something to call out, but unfortunately even now all too many frames out there are being designed for one or the other. So no matter what motor you match to this frame, you won’t need to worry about the mounting pattern. 


The space between the side plates is 19 mm, so you are  pretty much restricted to a full size camera. A micro camera with a 14mm form factor can be fitted as long as you use packing or spacers. Although that’s not an optimal situation for camera mounting. This frame came out before the likes of the 14 mm form factor Caddx Polar Nano and Nebula Nano pro, at a time when a 19 mm  camera was really the best option. It would be good to see this frame come with a 14 mm camera space in in future editions. 


This frame is a Contracted X (Not a True X), meaning that the arms on each side are at slightly less than 90 degrees to each other. A contracted frame is where the front and rear sets of arms have been moved toward eachother. This makes the whole frame wider than it is long, and brings the body (and camera) out level with the front motor mounts, allowing for an unrestricted view from the camera. I fly with a camera angle of about 35 degrees, and the props are barely in view in the bottom corners of the screen.  A Contracted True X is my preferred airframe configuration for freestyle


The kit comes with a variety of TPU mounts. The VTX mount is suitable for both DJI and typical analog UFL connector types. There is also a crossfire antenna mount for larger antennas and a go-pro style mount. While the VTX mount attaches to the standoffs, both the other mounts need to be attached with the frame bolts themselves. This unfortunately doesn’t allow the bolts to be tightened down firmly. The best option is to use some Locktight on the thread and also use M2 washers to spread the force over a larger area on the mount. 


The central 20 x 20 mount can be used to mount an AIO flight controller with either an analog VTX or naked Vista above. If mounting separate 4 in one ESC board and flight controller board, there is enough space above for an analog VTX only – even a naked Vista will be difficult to fit. 

Using the dual 20 x 20 mounts is better for when you have a separate 4 in one ESC board and flight controller board, and you want to mount a Vista unit. In this configuration, you even have enough space to mount an encased Vista unit.

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