What would be the advantage of getting a rotor kit 3.5” skylite over say a geprc smart35? The rotoriot kit is over $200 more but has a better F7 FC and I love the removable arms and option to easily add ducts. But is that really worth the extra$$? I can’t decide which 3.5” quad to get or build. I keep going back and forth. I really like the skylite because I want to add ducts seems a bit pricy.

The Chinese BNF quads are essentially built for free compared to a builder like RotorRiot who is going to charge more for labor all else considered. Whether they're giving you more options, using better parts, doing a better build, giving you a more refined tune or giving better support is debatable.

Building your own quad is like building a PC, you don't necessarily save money but you do get to build it how you want with your own choice of parts which almost always costs more.

In this category, the weight is absolutely the key feature of the quad. It directly determines how the quad will fly and the influence is greater than in the 5 inch category. That's just the way it is. Do not believe in idle talk and boasting, any advertisements. If the 3.5 inch quad is heavy, it will behave diametrically differently than the light one. It doesn't really matter who makes it. If you want replaceable arms, 3.5 inches will always be heavier, physically it cannot be made light, it will fly like a tank. And the biggest part of the total weight is the battery, if you have a heavy frame, you need to use a bigger battery to fly for at least 5 minutes. And the bigger battery makes it an even bigger tank and the whole thing gets exponentially worse.

I have tracked a total flight weight of around 215g as optimal for freestyle with 3.5 inches, weight above 250g makes it a harder to control cannonball. Weights below 190g, which none of the mainstream manufacturers even reach (Crux is at the limit), lead to an amazingly controllable race quad, turns without delay, but does not have the inertia, which is needed for freestyle.

Getting to 215g with a camera is again basically impossible with commonly available quads that are moderately durable, without a camera you can manage it with e.g. the Smart 35. The Crux 35 is very subtle and its arms crack in the place of stupidly chosen holes for the stack, but the weight is significantly lower. The Crux is also a trueX frame, those are less agile frames, so if it's for freestyle, I prefer squashedX.

So, of the originally intended quads, the Smart35 is the closest, only a little heavier. If the O3 airunit is installed, it will produce 4K video at a weight of around 220 g, but the price is of course elsewhere...

fly with ducts and without does requre a different pid tune to get good flightabilities.
i like versatility, it would be nice to have a quad which can do a bit of everything. sadly i believe you will get something nowhere good if you plan to get more versatility than possible.
you might be able to fly it with ducts and it might fly but as a special as beginner, i would suggest to choose one quad for one particular use. a slowflyer with ducts or a common one without ducts - i beleive you would get more by this strategy. overtime you will feel the need for more than one quad :-)

personal i would vote for the inexpensove lightweight happymodel crux35, i like its concept, i fly near builds.

there was a happymodel which was sold with ducts to add them, like your thought for double use, as told abpve i dont believe its a good option.

if rotor riot label a product, you will pay for their online show next to the product ;-)

And as for the ducts, the quad without them and with them is a completely different quad. With ducts it is significantly worse, the efficiency of the propellers in the ducts will decrease, lower flight performance and flight time, the quad is significantly less agile.

And I completely agree, and this applies 100%, for each task a slightly different drone is needed, one drone cannot always succeed. It wasn't really told from the beginning what you wanted to do with the quad.

My Crux35 analog + finder + GPS = 116.51g
4S GNB HV 850mah = 69.5g
4S Li-Ion 18650 vtc6 3000mah = 210g.
Crux35 flies on all these batteries.
My next project - frame AOS 3.5 o3 analog vtx, motor 1604, FC hakrc aio.

I have two EMax Babyhawk II HD's, both Vista Nebula Pro, one FrSky, the other ELRS.  Added to both is the to my mind essential Finder 2.

Since I fly at a closed to public area where sub 250G is not vital, most of my flying is done with 1100mAh 4S HV GNB pushing it a little over.   If I need to fly under 250g I use Tattu R Line 850mAh 4S.

The lack of inertia due the lower weight than a 5" does affect smooth freestyle, and for my type of flying, the extra weight of the 1100mAh is the right combination of weight (inertia), power and duration.

I'd had an uncommanded roll to perfect invert (to ground) on the FrSky one, and this video was done to explore and visual clues if it happened again. It didn't and hasn't!  DOH!

I also have a tiny judder that I cannot track to remove, but the video shows at around 5.00 how little inertial "fling" the climb provides in the reversal move.  (and the 850 is worse)

I get FAR better hang time on my 5" quads.

After about 300 flights, I took the time about a month ago to modify my Smart 35 HD frame a bit more. I stripped Vista, so I saved about 10g right away. I shortened all the wiring to a minimum, threw away things that are not needed, and even more can be thrown away, I left the camera protection there. I used shorter screws and thanks to the space saved with naked Vista, I reduced the height of the entire frame by 4 mm, I shortened all standoffs and camera side plates. I also used a lighter battery strip. Well, the result is in the photos. I like a bit lower height appearance. I got to 120g without battery and a naked GoPro, which is not a bad result considering the arms are 4mm thick and the frame can take quite a bit of rough handling... it do not look like 300+ starts quad ... True, before tuning I threw it in the sink and washed it thoroughly. :-)

Tons of great info. Thanks everyone. I have to admit I am kind of hell bent on a multipurpose quad. But I’m not against converting my crux3 to a cinewhoop for the few times I want to do video. All your comments kind of have me leaning towards the smart 35 or a custom build. The AOS frame was one that I was actually looking at.

I happened to come across a Skylite presentation video today. Can someone explain to me why the quad is called Skylite? Because this quad is a typical example of a tank. Of course they don't mention the weight in the official description of the quad. People want to be deceived...

(06-Mar-2023, 11:59 AM)MomoBrut Wrote: I happened to come across a Skylite presentation video today. Can someone explain to me why the quad is called Skylite? Because this quad is a typical example of a tank. Of course they don't mention the weight in the official description of the quad. People want to be deceived...

Looking at the description: "Drib designed the SkyLite as a smaller, lightweight version of the Skyeliner."

That reminded me of why he called his larger frame Skyeliner is because he wears eyeliner. Probably best not to expect too much on frame naming from Rotor Riot.

(06-Mar-2023, 02:28 PM)sevro Wrote: Looking at the description: "Drib designed the SkyLite as a smaller, lightweight version of the Skyeliner."

That reminded me of why he called his larger frame Skyeliner is because he wears eyeliner. Probably best not to expect too much on frame naming from Rotor Riot.

I got side tracked with upgrading my Crux3 and ended up ordering parts to build a 2s toothpick with a petrel frame, X12 FC, and 6400kv motors instead of upgrading lol. But I am still planning to build a 3.5" build. I think a nice 5" build would be great but I dont have a lot of places and space to fly on a 30x30 mile island tha primarily ocupied by airpoirts and military so I am still looking at 3.5" builds. Probably using the AOS Frame.

I dont have any 3.5" builds.
3.5" is basically a 4" build with few mm smaller props.

For those who like long flight time and extreme maneuvrability.
My lightest 4" was 81g. I used 80g 750mah Tattu batteries.
4" 4025 Xing1404 3800kv. JHEMCU F411 30A AIO. Key was the 14g Picklefork frame.
Can easily go even lighter.

i fly 1306 4000kv on 4s and hq3,5", their response is awesome - i would like to see that on a bench test :-)
4inch blades doesnt match that well on the emax1306.

some nice testing on 3.5inch rotors, sadly no 1306
https://intofpv.com/t-recursion-labs-sub...er-testing

4inch frames got popularity, but 3.5inch is still pretty rare on the market. there might come more support on that size, as weight limitations does match that size pretty well.