FPV T Rex 250 Setup

[halley]

Here's my "little bird" FPV trainer, the T Rex 250.

I got about ten FPV flights in, at the end of last year (2009)'s flying season. Everything seems to be working pretty well. I did end the season on a crash, the gyro wasn't initialized properly so I launched in a nice spiral. I repaired the little tyke easily, but haven't flown due to frozen fingers syndrome. Another week or two, and it'll be semi-dependable flying weather.

Before I crash it again, I thought I'd take a couple quick photos of the idea.

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Plain old Align T Rex 250, getting a little sloppy after a whole season of learning to fly. Standard types of flight equipment: Futaba FASST R617FS receiver, Align GP750 gyro, Align DS410 cyclic and DS420 tail.

My camera is an SN777 12V. That's the smallest quality camera I found. It's fit into the nose of a plain Align unpainted fiberglass canopy (the cheapest canopy option ends up being the best). I used some medium-density scrap foam from a hobby part's packaging to make the camera grip inside the canopy nose. It's the same kind of foam that the common heli blade restraints are made from.

I hand-built the dipole antenna on the tail, using hobby brass tubing and a spare boom clamp. The rest comes from DPCAV, including the 900MHz 500mW transmitter [KB1TCT] and inline bandpass filter. The dipole works a bit better than the standard 2dB or 3dB omni dipole ducks I have gotten, and it's a third of the weight. I have no way of measuring field strength, though.

The video stuff is powered from the balance plug of the flight battery. Beyond the use of the bandpass filter (to avoid swamping my control receiver), I don't really care much about strong video quality... this is a training bird that stays within a few hundred feet of my groundstation. The heli is too small to add much in the way of toroids and tinfoil and stabilizers and onscreen displays.

I'll post a walkthrough of my groundstation along with video examples, once I get flying again in a week or two. I burnt out my last Pinnacle recorder, but have got that all sorted out and I'm just waiting on weather at this point.

I'll also show my T Rex 600 that has a (hopefully) more fine-tuned FPV setup, but I haven't gotten a chance to fly it by FPV yet.

[Mael]

love it
makes me want to get a 250 again
did you tame it down alot
and how is it flying outside

Mael

[halley]

Originally Posted by Mael

love it
makes me want to get a 250 again
did you tame it down alot
and how is it flying outside

I've never flown it indoors, actually. It flies just fine outdoors, but you will notice it bobbing if there's a breeze. (I fly with a gentle but highly turbulent wind in my simulator to train for good collective management.) I also never added any expo or flybar weight to "tame the heli."

[l14m]

Nice one Halley, does the dipole antenna improve the reception between ground station and heli ? and if you bank the heli do you get less drop outs of the picture. Ive been looking for some guidence for making one for 1.2ghz .If you could do a 101 on dipole making it would be great. Looking forward to some vids.
Regards Liam.

[Crash9]

Nice 250 and cool dipole antenna. I've been eying the 250 and wouldn't mind setting one up for some FPV to replace my CX . Keep us posted and some video when the weather improves.

[skyhigh]

I am also building a 250 FPV platform. I've been flying alot on my 500 FPV and did some 450 FPV earlier last year. The 250 FPV will be bare bones like yours with no OSD, gadgets, etc.

I mounted my Sony Petite NTSC camera between the skids on the undercarriage of my 250. I am using the 250 SE skids because they are taller and give just enough clearance. I'm concerned that the nose mounted camera would take very bad damage if you crash nose first.

I also run a home made dipole antenna that is just made out of the end of a coaxial SMA extension cable and using the metal sleeve from a rubber duck antenna. It mounts on my heli's tail vertical stabilizer. The home made solution gives the same performance as a rubber duck antenna without the weight. I use heatshrink wrap and a drinking straw to keep the end wire parallel with the sleeve even during high speed flight to maintain the dipole EM field.

Will post pictures when the bird is ready. Almost there.

[jeremy cooksey]

hey guys. i just got my first fpv setup from Tim at readymade (its the beginner combo he just added),900mhz 500w. setup on my blade 400 but im wanting to put on my t250 .i just feal better on the 250.is there a better way to setup the antenna than stock.?Halley if you could tell me the parts to make that antenna it would help.If I mount mine like your pics. i would have to make me an antenna because mine just swivels on the transmitter.any help on setting my 250 up on fpv would be GREAT.rite now im using spectrum rx tx on helis and my laptop with the easycap setup to monitor and record.Haven't got the guts to just stare at the monitor and go.but been practicing on my g5 sim..Thanks also have a blade cx2 .would it be better to setup on it? it just dont fly worth a crap in the wind.

[halley]

Start here: http://www.rcgroups.com/forums/showthread.php?t=1159968

[jeremy cooksey]

Looks like this will help alot. Thanks. Did the 250 help you out on learning to fly fpv?

[jeremy cooksey]

Here's mine. I built me a dipole antenna. Hope I did it rite. Any directions of building a patch antenna for 900mhz 500w that's easy to follow? Does anyone know how far the 2.4 spectrum tx rx setup for heli with ar6100e will be able to fly? Thanks

[jeremy cooksey]

The antenna I built from SMA female I bought from radio shack