Help! Light weight rc plane setup

[Superman]

I am trying to build relatively light rc plane which I could just cruise at a nearby park. My goal would for it to be under 250g, but I know that it is quite hard to achieve. Do far I have gathered these parts- 850mah 3s lipo, 5inch 3- bladed propellers w 1806 2700kv motor (Now I am starting to think, that lower kv motor with larger prop might be more efficient), speedybee f405 wing mini. All that is needed now is FPV camera and vtx. I am leaning towards caddex ratel 2 because it is relatively cheap and gives night flying capability. And for vtx and atenna I have no idea.

Feel free to criticise also the parts that I already have if needed.

 

[Shurik-1960]

The smaller the wingspan, the smaller the size of the propeller and the larger the KV of the engine.This is an axiom. Install everything on a Chinese throwing glider with a span of 70-100 cm and you will have flying happiness with FPV.

 

[Tench745]

I am trying to build relatively light rc plane which I could just cruise at a nearby park. My goal would for it to be under 250g, but I know that it is quite hard to achieve. Do far I have gathered these parts- 850mah 3s lipo, 5inch 3- bladed propellers w 1806 2700kv motor (Now I am starting to think, that lower kv motor with larger prop might be more efficient), speedybee f405 wing mini. All that is needed now is FPV camera and vtx. I am leaning towards caddex ratel 2 because it is relatively cheap and gives night flying capability. And for vtx and atenna I have no idea.

Feel free to criticise also the parts that I already have if needed.

I have found that building under 250g is not particularly difficult. As an example, my FT Mini Scout is just under 180g with a 600mah 2 cell lipo.
The parts you have could certainly work in an aircraft of similar size.
If you're looking to build something unique, weigh your electronics, add in the weight of a reciever and ESC, and see how much weight you have to play with before you hit 250g. Then weigh a sheet of foam board (Dollar Tree foam is the lightest I've found) and build an airframe that fits within those limits. Substituting White Gorilla glue instead of hot glue will help keep the weight down. Peeling the paper off the inside surfaces of the fuselage and wing helps reduce weight as well.

I currently have five planes that weigh less than 250g ready to fly and one of them is under 100g.

 

[quorneng]

A good point about checking the weight of all the proposed "electrics" to see how light the airframe needs to be to keep within the target. Don't forget the weight of the servos. The lighter the plane the less powerful and lighter the required servo.
Using the right foam and airframe design is the bit you have most control over.
I try to make my sub 250g planes a big as possible to keep the wing loading and thus the flying speed within reason. Remember small smaller a wing the less efficient it is at creating lift.
As suggested it is possible to take a foam chuck glider, like a Lidl, add simple RC and keep it below 250g.
This is mine at 226g with a 800mAh 2s.

Aileron,Elevator,Throttle but no rudder. 3.7g micro servos. Flies nicely but not the simplest conversion.
When built from scratch things can go further.
All thin Depron foam sheet apart from the fishing rod tail boom.

Aerodynamically more efficient and bigger than the Lidl at 1100mm (40") span with a bigger diameter 1300 kV 24g motor driving a 7x6 prop. It is even lighter at 219g even with an 850mAh 3s LiPo on board. Dramatic performance but it needs so little throttle to just cruise about it can stay up for a long time.
It just needs careful design and attention to detail.
Do let us know how you get on.

 

[JasonK]

here is a design that I created for FPV, sub 250g

Plane - sub 250g FPV ATail Pusher

Built instructions: https://forum.flitetest.com/index.php?threads/a-tail-pusher.64421/ Big thanks to @FoamyDM for turning my pictures into plans that others can use.

forum.flitetest.com

probably a touch on the fast side and requires very careful packing stuff into the fuselage - but it does show an easy way to get there

another good option:

have this still on my shelf, flies great:

75% FT Goblin (strix nano goblin sized)

I had posted this on the FB page yesterday and it there was quite a bit of interest. This isn't exactly a 75% FT Goblin. I made a few tweaks and changes to make it fit on a single sheet of foam. Builds pretty much the same as the FT goblin (or really any other FT plane). A few notes. I prefer to...

forum.flitetest.com

this should work [at least in theory]

FT Mighty Mini Sparrow MKR2

Discover the versatile and educational FT Mighty Mini Sparrow RC plane. Build as a free-flight glider or a 3-channel RC platform in under 45 minutes!

store.flitetest.com

this should definitely be able to be made to work:

FT Mighty Mini F-22 Raptor MKR2

Conquer the skies indoors or out with the FT Mighty Mini F-22 Raptor. This RC plane is easy build with a versatile design for flying in tight surroundings.

store.flitetest.com

flite test has [had] some other plans that use smaller motors, but it seems like they might be retired as I can't find them on the store any more

searching Youtube for sub 250g FPV get plenty of hits that look like viable options.


That said, I found a slightly smaller motor is more then enough for sub 250g and the smaller motor easily saves you 10g and maybe another 5-10g on the ESC over the FT A- pack stuff it sounds like you have and when going for sub 250g, every gram matters

 

[Superman]

Hello, finally got a break from university! Just soldered all the pins for the FC and also I found an old AIO fpv camera and I am wondering if I could use it with my FC ( just so I could save some money and also weight). I am trying t figure out what each pin does. Here is what I have done:

I measured voltage (the colour of arrow represents the colour of the spike of multimeter)

Also measured the resistance (powered off)

Sooo I came to this conclusion

Now comes the question. Is all I have done right? Could I run wires from the "signal" and "ground" to the FC so that I get OSD? If yes then I suppose that I somehow need to remove the signal pin that is between the camera and vtx boards in the AIO fpv camera?

 

[LitterBug]

You have to split the video pin between the camera board an the transmitter board. Then you need the side on the camera to go to Video In on the FC, and the side on the transmitter to go to Video Out on the FC.

 

[Superman]

You have to split the video pin between the camera board an the transmitter board. Then you need the side on the camera to go to Video In on the FC, and the side on the transmitter to go to Video Out on the FC.

So did I name all of the pins correctly?