[secant0give]

Artemis is a model I've been working on for a while. It's basically a double up in dimentions of the model pictured in my Avatar.

Here's a pic of it Assembeled to check the C of G today

   

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I should realy say I started this a while ago and have just gotten back to doing some more work on it

Some more pics and a build log
can be found here.


http://fpv-community.com/forum/showthread.php?tid=854&page=1

[Claudius]

Nice Jason. Enjoyed reading through the build thread.

Very interested in talking to you more about this next time we're at the field. Any idea what the AUW is looking to be (minus FPV gear)?

(regarding the Airtruk reference in the build thread: my father worked at Transfield, and one of the engineers there gave me an Airtruk maintenance manual when I was very young. The whole site was just an awesome place to visit, which I did frequently growing up - all those massive factories and heavy machinery!)

[kizza42]

Awesome job, can't wait to see her go!

[secant0give]

Claudio, I just weighed her then on a good set of scales.
All up weight is 3.56 Kgs this includes 2 X 3S 5800 Lipos, all servos motor and ESC and FY-21AP OSD and auto stabeliser and frsky reciever.
This weight does not include the video Camera, VTX or lipo pack for OSD VTX and camera
I must say I'm pretty pleased with the weight.

Specs below are off my quick wing loading calculater spreadsheet.
I like the bottom line 18oz per Sqft. I don't think there are too many models with a wing area of 7 sqft that come out this light. Mind you she's not designed to be an areobat. (I will have to remember this)
This is the motor I used,
http://www.hobbyking.com/hobbyking/store...800kv.html
One of the reviews says it flys great 3d with a 6lb plane so it should fly OK with this 8Lb air frame. another review mentioned a trainer that weighed 3.6Kgs so I think it's in the ball park.

It should have quite good endurance if we can average 18A then flying time should be 30 mins with 8 mins to spare. Using the 3S packs in parrellel, perhaps I'm being a little optemistic here???? time will tell

wing span mm 2160
Cord mm 300
wing area mm^2 648000
wing area in^2 1004.402009
wing area ft^2 6.97501395

weight Kgs 3.56
weight oz 125.5776218

wing area sqin 1004.402009 insq in one sqdm 15.5
wing area sqdm 64.8001296
wing area sq ft 6.97501395

weight Lbs 7.848601362 range 16.0-17.5
weight Kgs 3.567546073
weight oz 125.5776218

loading 18.0039241 oz per sqft

[secant0give]

Finally managed to test fly this bird yesterday.
Pretty uneventful really, It flies slow and easily with nothing unexpected
Stall speed is very slow and it sinks in quite quickly as it's pretty dragy with that big fuse. Makes It very easy to land.

Here's the video Drew took

http://www.youtube.com/watch?v=AWKUYDR3RIc

[samste]

Finally managed to test fly this bird yesterday.
Pretty uneventful really, It flies slow and easily with nothing unexpected
Stall speed is very slow and it sinks in quite quickly as it's pretty dragy with that big fuse. Makes It very easy to land.

Nice Job Jason On The Build , I was amazed by how big it actually was, and how light it was.
And some very Clever Ideas in The build using some not so ordinary items, i really like the idea of using the carbon arrows with the threads already on the ends.

As for Flight Performance , should be perfect for Fpv as it Glides well

Steve

[secant0give]

Thanks Steve, It was a lot of fun to build
Here's some video of the taxi testing last week

http://www.youtube.com/watch?v=c0L11VmEVLM

[secant0give]

I was looking at some more Lipo's for this model as I only have one set
it currently uses 2 X 5800 3S 25C Turnagy packs in parrelell

I started looking at specs for different packs and came up with a list of their vital stats. It seems the lesser C rating packs have greater energy density. And the best compromise is 2X 5000 15C 4S in parrelell.

   


Here's the spread sheet if you wanter to tinker with it

Lipo pack comparison.xls Size: 17.5 KB  Downloads: 179

[Skidz]

Yep. I am inclined to agree with you Jason on the lower C ratings having the higher energy density. I think that is because with the higher C rated batteries, the extra weight and bulk is from carrying more electrode surface area in the cells to get higher discharges. The extra weight doesn't come from more Lipo juice. Same W/hr, higher weight, bigger size, bigger punch.

I'd wager a bet and say the batteries with smaller cell electrode surface area get hotter quicker too. Meaning 15-20C batteries will puff prematurely. I guess this is all fine if you have a power plant that plods along and is not trying to break the sound barrier with brute power.

[secant0give]

A test with the new 4S lipo packs and the camera gear on board with ground station recording and a test of how she handels a bit of breeze as well !!

http://www.youtube.com/watch?v=O24IeGkXJU0&feature=feedu

[Skidz]

"Epoxy Airlines"... classic.

[wingtipper]

soon we'll be seeing real FPV with this flyer .

[kizza42]

I've seen bricks with better glide ratio's, I love it!

[secant0give]

I've seen bricks with better glide ratio's, I love it!

Your right !!, the good thing about it being so dragy is that there's not much chance of over speeding it in a dive.
It doesn't seem to pick up much speed at all when you put the nose down and it really does sink in when you back off the throttle which means its easy to get down in a small place. But the disadvantage is that it's not very efficient. I think a slicker fuse would certainly help out a bit. I might make another one at some stage.

It's so ugly you've just got to love it

[secant0give]

I've seen bricks with better glide ratio's, I love it!

Your right !!, the good thing about it being so dragy is that there's not much chance of over speeding it in a dive.
It doesn't seem to pick up much speed at all when you put the nose down and it really does sink in when you back off the throttle which means its easy to get down in a small place. But the disadvantage is that it's not very efficient. I think a slicker fuse would certainly help out a bit. I might make another one at some stage.

It's so ugly you've just got to love it

Some video from Saturday

[brotherblonde]

What a great flight Jason. Beautiful landing too!

[secant0give]

What a great flight Jason. Beautiful landing too!

Thanks Andrew

[samste]

Very Nice, Still reckon you could have gone further. Just need to bring the Binoculars next time.

Well Done, Tracking Doe's make a difference

Steve

[wingtipper]

yeah i enjoyed that vid mate .

[secant0give]

Very Nice, Still reckon you could have gone further. Just need to bring the Binoculars next time.

Well Done, Tracking Doe's make a difference

Steve

Sure does as soon as you started tracking the antenna the reception improved out of sight !!

[secant0give]

I started building another Artemis, this one is slightly smaller at 7 tenths the scale of the big one. It's going to slipperier through the air, has a semi-symmetrical tapered wing and should be more lightly built as well.

Still using arrow shafts for the tail booms and this time just depron for the fins, rudders, stab and elevator. the wing is balsa skinned light EPS. the fuse will be mostly Soft EPP foam. It will come apart into a small is neat package and use carbon spars aligning the wing halves. It's 1.4M span

Here's some pics of the tail booms so far

   

   

   

   

   

[Flying fisho]

Looking good Jason, you never fail to amaze me with your enginuity in building models of your own design. Keep up the good work

[secant0give]

Looking good Jason, you never fail to amaze me with your enginuity in building models of your own design. Keep up the good work

Thanks for the Kind words Wayne,
Here's some pics of a little more progress done today
Fins are on rudders and elevator are hinged. This tail group is super light!!
So are the wings. The carbon spars arrived from carbon fiber Australia today so I will continue work on it next week with a little luck.

The tail group is just sitting on top of the wings to give an idea of the layout when it's mounted properly the wing will go between the two shafts that make up each boom and the plywood link will be bonded to the carbon spar that will be sunken into the wing. more pics to follow

[wingtipper]

pretty much a real flying wing . looking forward to see how this one flies . can see a real fpv setup here in the MKII . Have you thought about camera mounts etc ,,,,,,

[secant0give]

It will have a fuse a bit like the first Artemis but a bit slipperier

The big one is set up for FPV just been waiting for the field to dry out a little to take it out for a fly. should get it down there one day soon.
Need to do a little more flight testing lign of site first then need to organize a spotter and program another TX to be the buddy box. It should then be right to fly FPV.

[secant0give]

Well it looks like the building weather has set in so I've done a little more on the new machine

Here's a couple of Pics of the early stages with the Fusealage

The shape of the fuse sketched on the side of a block of foam

   

The fuse side profile cut out and checked for size against the rest of the parts

   

[wingtipper]

no doubt about your building techniques mate

[secant0give]

I thaught I'd add a bit strength to the EPS fuse by bonding on some 20mm wide strips of 1mm ply, one on either side and one along the center on the bottom. This is the only reinforcing I will add to the fuse, the strip along the bottom should also provide a place to bond the tow hook for the pneumatic launcher.
I used West Systems Epoxy mixed with West Systems Micro-light filler as the adheasive. It's much lighter than using straight epoxy and goes a hell of a long way. 25 ml of epoxy mixed with sufficient filler to make it stiff enough not to drool bulked it's volume up by 4-5 times, I used less than half of the mix to glue on the ply.
It added an amazing amout of stiffness to the fuse and very little weight, just what I wanted.

For a bit of contrast, the fiberglass moulded fuse that came with the sadler vampire weighed in at 500grams bare and it's about the same size. I havent weighed this one yet as it needs some more work and the motor mounts added to be fair, but I'm hopeing it will be well less than half that.

Now to do some trimming and some more shaping !!


Here's a couple of pics of the fuse so far

   

   

[secant0give]

And after some lunchtime carving and shaping

   

   

[secant0give]

I've repaired big Artemis after her trip out west to Boggabri. mainly it was only the nose wheel and the former that it mounted to.
She's been upgraded with a much better camera for the video link and she now carries a go-pro for onboard recorded HD Video.
I also replaced the RC Link reciever with a much better one as this was what caused the crash in the first place. The main power lipo packs have been shifted slightly to adjust the C of G due to the addition of the Gopro. I also replaced the elevator servo as I noticed it was just slightly jittery.



Here's a pic of her ready to go again

   

Video of the last flight can be found here. It was with the old camera and recorded at the ground station

http://www.youtube.com/watch?v=-1Yg1oFMq1M