Foam glider for keychain size camera...

[shagrug]

      Here's a fairly simple and quick to build foam glider I made for hauling up my new HD keychain camera. I lost my old non-hd camera back around the end of summer along with the 18" Parkzone Cub I'd been using all year to take it up, so this is the replacement plane. Bigger in span since the little cub was straining to carry the extra 16.8g load, along with being very hard to see way up there.

      I wanted a all foam design since I'll be flying over rough fields and trees, where a film covered plane would get full of holes quickly. I also wanted to enclose the camera and flight battery since it's winter and cold outside. I used the outlines from the Blu-guppy design scaled down to about half-sized for a 54" wingspan. The length is 27.5" and weight with camera and 350 mah flight battery  is 112 grams. (89.5g empty) The wing area is around 250-260 square inches. I also wanted the motor behind the camera, so I thought a retracting motor would be good to try. There is a build thread at RCG for the original Blu-guppy glider- this is where I found the attached pdf files from. My thanks to the original poster, it's a great looking design.

      It's made from 1, 2, and 3mm depron and garolite fiberglass scraps (.010" and .031")... the pushrods are .030" cf rod with .015" music wire ends. The construction is simple and I think the photos explain it all. I just eyeballed the airfoil and most of the demensions not covered by the plan outline, which I traced off the pc screen with pencil and paper. I was in a hurry to get it built and skipped taking pics here and there, so just ask if you have any questions. I thought later on about making the wing a 2 or 3 piece to make it more portable, but too late. 

      The wing's bottom sheeting is 2mm depron with a 10mm x .5mm carbon fiber brace down the COG point...smaller 5mm x .5mm cf is used on the outer wing panels. The 1mm and 2mm foam sheets are only 14" wide, so the wing has to be spliced in the center section. The "spar ribs" are from 2mm foam, added in as shown. The outer ribs are tapered the last 6" to help close the 1mm thick top sheeting at the tips. The late Bob Hurd (durobatics) was a fan of this style wing ribs, and once sent me a couple samples. I've never tried it until now, and I sure like it. It's very simple and quick, and mabe stronger than conventional ribs using foam sheet. The 15 degree garolite dihedral braces are CA'ed to the cf to join the panels, the rest of the glue used was all UHU Por. Total weight of the wing was 48g.

      The fuse is from 3mm thick (sides) and 2mm (top/bottom/insides) foam and sized to hold the keychain cam in the nose- there is a shelf with velcro (duralock actually) to hold it in place. The flight lipo goes underneath the shelf and also held by duralock so it won't slide around. I made the pushrods in the usual micro way, using heatshrink to join the cf and music wire ends. (locked with a microdot of CA) The stab and rudder assemblies are from 3mm foam and hinged with strips of clear shipping tape.
 
      The electronics are cheap stuff I've had laying around a while- a couple of new Blue Arrow 2.5g servos and a 4 channel "orange" spectrum rx (with pin connectors removed from the board). The speed controller is a 6 amp from Hobbyking, with no brand name I can see. The 5900kv motor is also from Hobbyking, listed here:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=17597
The motor runs well despite the incredibly sloppy winds inside, and feels like it puts out the advertised 55-57g of thrust. I've wondered what this motor would do with better windings, along with most other size motors I've bought from HK. I wish I had more time to experiment with them.

      I had a couple of small problems with the motor/pylon setup during the assembly- the first was by using a bad prop (GWS 4025) that vibrated and wobbled the pylon. Changing to a 4040 prop fixed this, running nice and smooth. But next when test running I cracked the mount down the glue joint- due to the motor pulling the pylon up very quick and with a good hard "whack" as it contacted the wing mount stop. So I had to add a couple of extra .031" garolite strips down each side of the post as well. After this it has worked fine, no problems. I've never made a retracting motor rig like this before, and I learned a bit from it. Next time I'll make the post wider and make a rubber or foam contact point to dampen the whack.  It's not a problem if I'm gentle throttling up, just when I forget it happens.

      I received a new 29g hd camera from hobbyking a few days ago that I like better than the keychain version. I'll have to exchange the heavy 850mah lipo on it for something a lot smaller and lighter (160mah mabe?) before I try to fly it. I would normally lighten up the keychain camera by removing the case and swapping the lipo but the glider needs the extra noseweight to balance. The COG is just right with the cam and a 250ma lipo in the nose- any less and it's too tail heavy. I noticed the CG shifts reward 1/2" when the motor drops down, someting else to consider.

      I've flown it around the yard some to trim it in, and now waiting for good weather to really give it a go. I can already see is a floater and not going to work well in much of a wind. The motor/prop gives a good steep climb of 45 degrees or better, so it should do fine getting it up there. The transmitter used is a DX7.

[shagrug]

The wing construction step by step- sort of... the pics are not quite in order as I posted them But it's all simple enough to figure out the sequence easy.

[shagrug]

more wing...

[shagrug]

The fuse details...

[shagrug]

more fuse...

[shagrug]

again more fuse...

[shagrug]

fuse and canopy...

[shagrug]

the last few pics...

[bamabaxter]

AWESOME!!!!!!  I wanna see video of it flying, not just onboard footage.

[sailsoar]

Danny, this is outstanding!!  Great work..........I learned a couple things.  Want to see the video now!
Mark

[relaxnfly]

AMAZING!!!! I just can't believe the all up weight for that wingspan:o  You might have to add an ounce or two of ballast just to keep it from flying away when the ants fart

Yes!! offboard video please

Michael

[Kerbob]

  Amazing craftmanship Shagrug! Truly a work of art and worthy of the AMA magazine again!  I too would love to see both a flight video and onboard video.

[romeodz]

So no retract servo for the motor? It simply pulls itself up and into position when turned on and self folds when unpowered. Awesome and simple. Great looking airplane.

[gittarpikk]

Hi Shag

  Killer sailplane...I didn't see it was your post until I started noticing 1mm depron, garlite...then looked , yep it's Shag

  I have never seen the vertical foam strips vs ribs before.. taught me a new one!..

  If the thermals die, heck just get out the kerosun omni  heater... That is a really great AUW...something your well known for.

 I did a sailplane way back in 80's that used the same type mount..except it was .049 and 8' wing...when the motor would lean it would pop up, down , up, down ..and make for some really scarey situations at about  500' with 8' of balsa wing out there flexing  . 8' of balsa and an .049 to haul it had to be built real light...so it was a bit of a 'gooney bird'...thousand wonders it stayed together.

[shagrug]

      Thanks all, I really appreciate the comments.

      I had it out today again but still no vid of it flying. (as I was alone) It flies ok, but really too light for any wind at all. I have been having problems with wind when it starts to get up above the tree lines.

      Also the rough stubble field I've been flying it from is beating it up and poking unexpected holes through the wing.

      So I decided to go with a solid foam RTF skyclimber (nine eagles), that can handle the wind and landing problems. I had it out for a few trial-trimming flights today at US Cellular, and like it a lot. The bigger size will help me, I was having trouble seeing the smaller one way up there. (like the Cub)