New FPV Scratch Build!

[rsnation]

Hi everyone! I'm a longtime lurker of the FT forums and for my first post I thought I would share my new scratch build design, a currently unnamed FPV pusher:



My goal for this plane was to create as efficient a design as I could make out of DTFB for mid range FPV flying while still retaining some mild aerobatic capability. I took a lot of inspiration from the Bixler series and the Volantex FPVraptor when designing this plane, but adapted for DTFB. The entire airframe was designed in Solidworks, first in 3D and then 2D templates which I used to cut my foamboard. More photos:



And a few selected build photos:



The wing is detachable and quite thin to improve efficiency; the build techniques used were inspired by the speed wing of nerdnic's nnMig3. I've set it up with an APM 2.6 and a 5.8GHz FPV system. Other specs are below:

Wingspan: 59.5 in
Length: 42.75 in
AUW: 1457g w/ 3s 5800 mAh battery
Prop: 9x6 APC E
Motor: Sunnysky 2212 1400kv
ESC: 40A Plush
Servos: 6x TGY-9018MG

I've only done some taxi testing with it so far and I'm hoping to maiden it this weekend. I'd really appreciate any suggestions to improve performance/durability/anything else. I'm also looking for ideas for a name.

If anyone is interested in the plans, just let me know and I'll get them cleaned up and posted.

 

[quorneng]

rsnation
Looks very nice.
I would be interested to see the details of the wing construction particularly as its a 'thin' wing.
As an aside a thin wing isn't necessarily more efficient they just have less drag at speed. On the down side for a given wing loading they can create more drag as slower speeds.
Then of course there is their structural efficiency (strength to weight) which tends to be worse than a thicker wing.

 

[rsnation]

quorneng:
Thanks for the feedback! I know the thinner wing won't help efficiency at lower speeds, but I figured that at my desired cruise speed (40-45 mph) I would benefit from slimming down the typical Flite Test fold over wing. I designed the wing to be nearly symmetrical with just a slight undercamber and then the typical Flite Test style undercambered wingtips to help with stall characteristics (although they aren't good for drag). The wing thickness is determined by the servo thickness and the 1/8"x1/2" aluminum spar I built into the wing.


The wing is basically built around the spar, with the trailing edge of the wing (and control surfaces) beveled to further reduce drag.



The last photo is the best I can do to show the cross section; I cut slots into the top and bottom foam pieces for the aluminum spar to rest in and glued foam pieces around it to hold everything together. The end result is a bit heavy (I wish I could have found 1/16" aluminum to use) but plenty strong enough for anything I might try with this plane. The wing ended up being about 9/16" thick, as opposed to ~1" for a lot of the FT designs.

 

[Spastickitten]

Amazing! I have been looking for something like this!

 

[nerdnic]

Nice work! I like your use of my speed wing design. I am working on a FPV platform as well. I had originally thought about going the direction you are and designing a Bixler style plane. I chose to go a different route and will be designing a predator drone instead. One thing I will not be doing though is using the aluminum spar like I normally do and like you've done here. My goal is for longer range and I fear the aluminum could cause signal interference in some scenarios. I will be using a carbon fiber arrow or possibly a wood dowel instead.

I will definitely be following along and seeing how your build works out.

 

[rsnation]

The Predator idea sounds awesome! With the rear motor you could load it up with tons of batteries/fpv gear without any cg issues. I'll be looking forward to that.

I'm not planning on going super long range with this rig (I'm limited by my L9R receiver and 600mw 5.8 fpv system), so I wasn't too concerned with interference from the spar. I would think that the carbon spar would be just as bad as the aluminum though. Wood should work well as long as you can get the wing stiff enough, or maybe you could also consider a fiberglass spar.

 

[nerdnic]

What kind of range are you planning to get with your setup? I've been talking to a friend with a L9R, 600mw 5.8 set up and he's getting 6+km. I'm going with a very similar setup so I guess when I say longer range that's the ballpark I'm shooting for.

The dowel is gonna be my first bet but if it's not strong enough the carbon tube/arrow was option 2. It should have a lower profile than aluminum so I figure it would be a safer bet. We shall see

I've not picked a wingspan yet but I'm hoping to hold around 10,000mah 3s.

 

[Jaxx]

I read somewhere that carbon fiber could potentially cause signal problems as well. Can't remember where I saw that.

 

[Kurt0326]

Nice work. I'm trying to get in to 5.8ghz FPV too. what fpv setup are you using?

im looking to spend $200USD for a setup, not with goggles. Thinking about a 400mw 5.8ghz, not looking to get more than my radio can reach. Flying a ft cruiser with Power Pack C (Fixed Wing Large) - TWIN ENGINEon 3s with a Taranis w/ x8r

 

[rsnation]

I don't have a diversity receiver setup yet, so I wasn't planning on going past 2-3km with my omni antennas. At some point I'll get diversity going and I might try 4 or 5 km on a helical. I think I could probably get about 8000mah 3s in this design while still flying relatively decently; I designed the nose to squeeze in 2 of my compact 5800s, but I'm worried it will fly like a brick at nearly 2kg. I might pick up a couple of the multistar 5200s and try a pair of those since they are quite a bit lighter.

I didn't want to go to a 3 piece wing, so I was limited to about 60in on the wingspan (although I did go with a fairly large chord to try to compensate). A 70 or 80 in wing would probably carry the weight quite a bit more efficiently.

 

[Kurt0326]

Wait, rsnation. I just realized, this is you first thread. That means...

WELCOME TO THE FAMILY!:applause:

 

[nerdnic]

I don't have a diversity receiver setup yet, so I wasn't planning on going past 2-3km with my omni antennas. At some point I'll get diversity going and I might try 4 or 5 km on a helical. I think I could probably get about 8000mah 3s in this design while still flying relatively decently; I designed the nose to squeeze in 2 of my compact 5800s, but I'm worried it will fly like a brick at nearly 2kg. I might pick up a couple of the multistar 5200s and try a pair of those since they are quite a bit lighter.

I didn't want to go to a 3 piece wing, so I was limited to about 60in on the wingspan (although I did go with a fairly large chord to try to compensate). A 70 or 80 in wing would probably carry the weight quite a bit more efficiently.

I think you could do 2kg but you will have issues with your aft fuse. It's too thin to hold that much weight on a landing. Even at 1.5kg I would be worried about rigidity over time.

 

[rsnation]

Kurt, I'm trying the Skyzone TS5828 transmitter with an Aomway 32 channel receiver with built in DVR. This is my first build with the TS5828, but I've gone out about 1km with the 200mw TS5823, and I'm expecting about double the range with the higher power unit. I'll be doing some careful range tests before I try going past 1km, though. The skyzone TX only runs about $30, and the receiver about $50, so throw on a set of circularly polarized antennas, and you'll have a pretty solid setup for under $100. Probably not quite as reliable as the Immersion gear, but you can't beat it for the money.

 

[Kurt0326]

Kurt, I'm trying the Skyzone TS5828 transmitter with an Aomway 32 channel receiver with built in DVR. This is my first build with the TS5828, but I've gone out about 1km with the 200mw TS5823, and I'm expecting about double the range with the higher power unit. I'll be doing some careful range tests before I try going past 1km, though. The skyzone TX only runs about $30, and the receiver about $50, so throw on a set of circularly polarized antennas, and you'll have a pretty solid setup for under $100. Probably not quite as reliable as the Immersion gear, but you can't beat it for the money.

hmm, and i'm trying to get out to about 1.5km. nerdnic has got me thinking about the Lumenier TX5G6 Mini 600mW 5.8GHz 32CH FPV Transmitter . But the 600mW TX will reach I think well beyond 3km. Not that it's bad but, I don't want to completely over reach me radio boundary.

 

[rsnation]

I was a bit worried about the aft fuselage when I first built it up; one downside to designing it entirely in CAD is you don't always get a good sense of the actual scale of things. I figure I'll just try to make sure I put it down carefully on the main gear when I land it, and if (read:when) I screw it up and bust up the tail, I'll look into beefing it up a bit (perhaps lining with 1/16" plywood?).

As for the 5.8 transmitter, that Lumenier unit looks like a really solid option. Personally, I wouldn't worry too much about outranging your R/C gear; the extra power will just give you better video performance closer in when you break line of sight, as 5.8 is pretty terrible at penetrating obstacles.

 

[airhawk]

great job on building very clean build id love to see plans

 

[rsnation]

I'll go ahead and post plans after I maiden it; I want to see if it needs any modifications first.