-A.J.R.V.- A high performance Flying Wing electric or slope (now with PLANS & video) - RC Groups
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Dec 14, 2010, 08:04 AM
the answer 42 is
Build Log

-A.J.R.V.- A high performance Flying Wing electric or slope (now with PLANS & video)


Well I had been thinking about this project already for a long time. I had approached this challenge very scientifically. I first reviewed the previous experiences with such models. Using XFLR5 I checked the performance of each of these and draw my plan.

The Task

"F5J" is a new and very interesting category, the task is simple 10 minutes duration flight and landing in a 1m diameter circle. And the pilot has 30 sec to climb up to 150 to 200m.

I will be developing at least three models, the first one will be the proof of concept and will have a very basic configuration.

A.J.R.V. 180
WS 180cm
Airfoils Ag35 HT 23
Weight ~600g
R/c: Elevons + Flaps

the following models are a 2.6m version and the final will be the 3.5m, the idea is to learn from each step and improve the performance of the plane using XFLR5 and Test.

Something interesting I had found is that to maintain the performance fo the wing to the Max it is necessary to adjust the CoG depending on the condition climbing(with motor), thermaling, , or landing. I think this will be easy to arrange with an extra servo moving the lipo.

I will be glad to hear all your comments, but if you do not think this will work just keep it for your self

Regards

EZ

PS: My design was inspired fro the FW of MiniPhase and Mr Kenichi

AJRV Flying Wing Slope 1 (5 min 35 sec)
Last edited by Edwinzea; Apr 19, 2011 at 03:35 AM.
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Dec 14, 2010, 08:18 AM
Registered User
miniphase's Avatar
adjustable cg! very exciting.....I'll be watching with interest
Dec 14, 2010, 08:37 AM
the answer 42 is
Hey Paul, I forgot to mention your planes as my main inspiration for this project

I was just doing some simulations on XFLR5 to maintain the best glide ration the CoG need small changes in a range of 10mm so it wont be to difficult to build

Still Have to work in how to reduce the trim speed with the brakes deployed, and it will need some real life test I have almost all the material and equipment to build it, I am just missing the joiners that my CF supplier forgot to put in my order :P

Regards

EZ
Last edited by Edwinzea; Dec 14, 2010 at 09:38 AM.
Dec 14, 2010, 12:33 PM
resU deretsigeR
PaulVi's Avatar
Adjustable CG can be done very simple with a sliding box you can add as much or as little lead to the box to fine tune the effect. a single servo can act as the control.

If you have room for a full sized servo you could use the servo as the wieght and have it slide back and forth on a rail system a full sized could give you one oz or more of movable wieght..
Dec 15, 2010, 03:39 AM
the answer 42 is
Hey Paulvi

thanks for the idea, actually I am planning to move the batery, so I dont have to put extra weight, but perhaps the lead box idea can be implemented on the next model

regards

EZ
Dec 15, 2010, 05:52 AM
the answer 42 is
I was working a bit on the model, I increased the size of the flaps and it seems to have a overall positive effect on glide ratio and lift. I just finished the CAD drawings, I hope I will be cutting the cores this weekend.

Regards

EZ
Dec 23, 2010, 11:56 AM
the answer 42 is
Yesterday I finally finished my automated foam cutter and got right on this project. I am using a "purple foam" similar density with blue foam but it needs more heat to make an even cut. I found that on the hard way, the first two try out were dissaster. I was having a bit of trouble cutting the extrados of the wings.

Now I have to figure out all the reinforcements and the wing joiners, because the ones I ordered are still in China, and in fact those are for the 2.5m version so they wont fit here.

I will post more pictures tomorrow

EZ
Dec 23, 2010, 07:05 PM
SlingWinger
Edwinzea,

Your designs look really good. Many years ago I made a large FW with a fairly thin airfoil, too thin for the battery, and I had no fuselage. This was before LiPo batteries, so I mounted my battery on a pylon about a chord length below the wing. It looked sorta kinda like a sailboat keel, with the battery in a streamlined bulb. It worked very well, but it's position was only ground adjustable. This glider had only 15 degrees of sweep, how much are you using?

I also once made an 8' wing with the battery mounted on cut-down drawer slides from an old filing cabinet. Very low friction. I connected the servo using rubber bands, to avoid stripping the servo gears in a crash.

I think a variable CG is one key to getting the most from a flying wing; that and flaps.

I'm curious about your taper ratio and the amount of washout you think you'll need. On my gliders I had good luck sanding in a larger, or more "round", leading edge radius in the outboard area of the span, This eliminated a tip stalling tendency without increasing washout on mine.

I'll be watching your progress with interest.
Dec 24, 2010, 01:05 AM
the answer 42 is
Hey DaydHead

well as you saw I calculated everything using XFLR5, but this is a proof of concept. the airfoils look so thin because it does not have the skins that will add 3mm more the thickness are 8% at root and reduces to 6.5% at tip. I am using 25 degrees sweep. There is no taper, the wing has a constant chord of 18cm.

As for the washout it is exponetial, I did lots of research and it seems to be the best option so it starts with 1.4 degrees and at the tip is 2.5, again is the most efficient combination I found in the simulations, but only with the plane on the air we will see.

I also read many articles talking about the variable CoG, but very little about practical experiences, so I did some simulations on XFLR5 and for instance adding camber with the flaps will increase the lift but will reduce dramatically the Glide ratio and efficiency, but with a change on CoG it is possible to avoid that.

Regards

EZ
Last edited by Edwinzea; Dec 27, 2010 at 06:30 AM.
Dec 24, 2010, 04:43 AM
Registered User
miniphase's Avatar
looking good Edwin, hope it comes out stiff enough!!

dayhead- I've used the blunted leading edge methos too, on a model with no washout, it worked well with no tip stalling evident, though the model was very light.
Dec 26, 2010, 04:26 AM
the answer 42 is
Thanks paul, well so sar looks stiff enough for the application, I an still considering another CF spar close to the flaps hinge, I will also reinfocer with GF the balsa wood skins to gime more torsional rigidity.

SO far is lloking nice, so I hope it will fly nice. SOmething I like a lot, but unfortunatelly cannot be seen on the pictures, is how the profile blends from AG to HT

I will do some work later today, and I will post some more pictures

Regards

EZ
Dec 27, 2010, 03:45 AM
the answer 42 is
Ok after chirstmast family day the build continues, now the skins are applied and the first wing is out of the form. It feels really stiff and the weight is about 170g. THe wing joines housing are made out of 2mm ply the joiners a two CF tubes of 8 and 4mm

The first CF leading edge is also installed and now the wing is ready fro trimming and fitting, next work is cut and reinforce falps and elevons

here some more pics

EZ
Dec 27, 2010, 08:04 AM
the answer 42 is
Some more pics, the wings are now fitting nicely, adn they weight 180 and 186g still need some final touches and will start with the flaps and servo instalation. I will be sketching the fuse later on.


EZ
Dec 27, 2010, 11:47 AM
SlingWinger
On Christmas day I got to fly a rigid wing hang glider, called "Atos" by A.I.R.
Being a rigid wing, weight-shift won't work for roll control, so spoilers are used instead.
The same movement as used with a weight-shift controlled flex-wing hang glider is used, but instead of my weight moving to the side, the control bar moves relative to the wing, pulling on cables that actuate the spoilers. Pitch is controlled by weight-shift, or as we say in RC, variable CG.
This glider has flaps, which are used to configure the glider for a certain task, with about 15 to 20 degrees used for launching and thermalling, and a slight reflex is used for high speed inter-thermal running. Also, the flaps set the hands-off trim speed, lowering the flaps lowers the speed by trimming the glider to a higher AoA, as well as increasing the lift coefficient. Full flaps kills the L/D, making an approach easy, even in restricted LZ's.
You are going to have a great time with your glider, having so many variables to play with.
I'd like to build one where the leading edge can be drooped for more camber forward in the airfoil, as well as trailing edge camber. Increasing the usable speed range is what it's all about, and the variable CG will allow further optimization for any given flight configuration. I'm watching with interest, this is exciting!
Dec 27, 2010, 12:35 PM
Registered User
miniphase's Avatar
Quote:
Originally Posted by dayhead
I'd like to build one where the leading edge can be drooped for more camber forward in the airfoil, as well as trailing edge camber.
It seems there aren't many home builders out there in the hang gliding community dayhead. The Mitchell wing seems to be the only real success and that was over thirty years ago? I'm suprised nobody out there produces plans for a timber rigid wing, surely you could build something really light and strong (enough). Gery on this forum was planning to build his own timber/composite Swift, but his thread went to sleep!

The wing's looking great Edwin, I flew my 2.4m version today with the revised flaps. They gave a slight pitch up (easy to compensate for) and slowed the wing a reasonable amount. I think they need to be twice as deep chord wise to really 'park' the model in the manner of my 2m wing.


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