Plane with vidcam xmtr and rcvr backpack with 13 element Yagi and Sony Glasstron VR glasses. Theoretical range with these antennas is 1-1/2 mi, so far I've tested out to almost 1 mi. Sony TRV310 Hi-8 digital camcorder used to record flights. 12V 7Ah gell cell, with 12v to 110V AC converter used to power avionics (even though all items can be powered from battery sources seperately). Rcvr antenna design derived from North Country Radio 5 element Yagi - 8 additional elements designed by me using EZNEC.
The video camera and 920Mhz xmtr with electret mike are mounted on the wing. The xmtr antenna is mounted just in front of the T tail assembly. Carbon on fuse does NOT come with the plane and is provided thanks to numerous crashes due to having the xmtr camera too far out on the wing, which would keep the left wing stalled too long after launch, causing the plane to rapidly rotate CCW into the ground. The above setup launches easily with full throttle and a clean toss.
For specs on the plane, go here. Bought from Deiter and Marcela at Shredair - you want the best? Talk to them.
PlaneThrust w/ 12x8 prop, MaxCim MaxN32-13D w/ Maxu35B-21 controller, 3.7:1 planeta gearbox, 18-3000maH Panasonic Nimh cells - 94oz (from Motocalc) Plane with gear total weight 107 oz Rate of climb full throttle - 1514ft/min @ 41degrees Battery time full throttle - 3:22 Typical flight time no wind - 15 minutes No wind no external lift max computed flight time at 59% throttle @ 47 mph - 32 mins Stall - 25 mph Cruise - 47 mph Max level speed @ full throttle - 76mph Amps - 53A Prop speed - 9200rpm Span 69" RG15 wing 580 sq in with flaps and ailerons. Currently 4 HS-81MGs in the wings, HS-80MG (old) in the elevator, Hitec slimline rcvr, rcvr antenna hangs out the tail. Video gear 920 Mhz 450 mw FM xmtr from Supercircuits - part # AVX-900-T2
Closeup of the xmtr antenna installation.
Detail of the antenna. This is a pair of crossed dipoles fed 90 degree out of phase, made out of 3/32" brass tubing CAed to a 1-1/2" sq piece of 3/32" plywood. The 3/8" hole in the center mounts a BNC connector. Radials are cut so length from center to tip is 3", with 1/4" space from connector to radial. Top right radial is wired to BNC outer ring. Bottom left radial is wired to BNC center.A piece of RG-174 coax, 3" long is cut, .75" is stripped from one end, .25" from the other. Connect center of .25" stripped end of coax to center of BNC. Connect shield to BNC ring. Connect other end of coax, center to lower right radial, shield to upper left radial. I have a BNC to F connector going to the BNC, and a 3' length of coax with F connectors running from there to the xmtr.
Test flight from Golden Gate Fields Waterpark (I'm standing near the big X center left). 880 and Albany are to the left. The Berkeley Marina is dimly visible below the bright patch upper right. This used a 5 element Yagi for the rcvr antenna, which is just the first 5 elements of the antenna seen in the rcvr antenna views - only about 6" long. Total flight time was about 11 minutes. Video is edited down but includes takeoff and landing, flying over the race track, out the peninsula, some rolls, loops, and the "patented" rolling dive, with pull out to vertical climb, transition to rolling climbout. For scale, the distance from the X to the end of the peninsula (just off screen to the right) is 4000'. The camera is wide angle, so objects are somewhat "fisheyed". You can roughly approximate distances using 2 to 1 rule. Every 2 ft seen on the ground is 1 ft away from the camera. For example, here, we are about 2000' from the peninsula. (approx 1500' alt, since view is angled). The camera has about a 15 degree down tilt relative to the wing surface.
eSpiro at Golden Gate Fields Waterpark- 30Mbytes mpg 360x240, 3:16
eSpiro - 00:20 - 1.7Mbytes 240x180
This is great example of how NOT to fly a plane with the CG too far
back. Here I had the camera and xmtr mounted on the T tail. Even though
i'ts only 5 oz, it shifted the CG back nearly 1". In these first tests,
a single rubber duckie antenna was used for both xmtr and rcvr antennas.
Very limited range (300'-500'). I had a 10 cell AAA Nimh pack (12V) in
with the main bats (18 cells 3000mah Panasonic Nimhs), but even though
the camera and xmtr are only 4 oz, it moved the CG 1" furthur back. You
may be able to see the Sony Glasstron VR glasses just under my hat. These
are a neat way to watch the image from the plane. Bright enough to see
in full sun, plus you can see under them to watch the plane. Focal point
is distant enough that you can switch back and forth not too painfully.
Bash 11/2000. The final 14 seconds of a mid-air and crash at Los Banos.
The culprit is seen as a double image, since the program I used extracts
both fields of video for a frame. There is one field additionally seen
just before the impact frame with the plane in view. Judging by the distance
the plane travels in these fields (1/60 sec), I'd estimate the closing
velocity at 80-100mph. The plane took off about 6 inches of an already
slightely damaged right wing tip. It's not clear if the collision or the
impact did it, but the right aileron servo control horn broke at the servo.
The right wing was also severely cracked just behind the spar - altho the
spar seems fine. econe and fuse pretty damaged as well.
Bash Crash - 2.1Mbytes 360x240 mpg.