|Feb 18, 2011, 04:06 AM|
Alula and Weasel Shape Based Slope Gliders.. A-clone and W-clone
Heavily based on the Alula and Weasel this build uses multi laminated foam layers of 3mm depron to produce pretty good gliding models..
The simply built wing uses 4 layers of 3mm depron and has a CF tube spar that is positioned at the COG..
The wings shape is as per the Alula or Weasel.. But I have used a longer built up Fuzz to hold the gear which gives you more room to fit all the gear..
I wanted to share this design because not everyone can afford the real Alula or Weasel, and this one does compare very favorably to the original..
The originals I am sure have an edge on performance, but these have a big cost advantage, and still go very well..
They use 1 and 1/2 sheets of depron ..1x 1m CF spar (use a 4mm sq spar for the neatest job, I used a 5mm round which worked ok but is a bit large)..
Uhu Por for laminating, Velcro to hold the gear in the fuzz, and colored packing tape for the decor.. some horns, 2or 3mm CF pushrods and links finish the list....
Total cost about £10-12 compared to the £60+ for the originals
EDIT NOTES... 1st build..small sizes.. The small versions shown at the start of this thread were found to be low wind fliers only , getting blown away at over 10mph.. The foam fuselages could not take ballast and were too weak and fragile
All of these , big or small need a re-think on the fuselages ...Use balsa or ply , not foam, they should have enough room to take ballast and be strong enough to take the heavy bashing that slope flying will give a model.. weight is not an issue, more weight will give better flights off the slopes
2nd builds..going bigger.. taking these bigger, more foam and a balsa fuselages , gets un-ballasted weights of 14-17oz ... this puts them into the mid wind speed ranges.. thats in the 40"+-50"range.. and ok in 16mph/25kph and more, all depending on how much ballast you can hold..
At around page 20 bigger models are flying.. un-ballasted they are floating well in the 25kph winds, along with a Zagi later for comparison...
I am also trying some different KF sections that use more steps.. The KFm11 and KFm12 which also go well
|Feb 18, 2011, 04:07 AM|
The decor uses 2" colored packing tape..The model is fully tape covered as this adds lots of strength and damage resistance to the model.
This project was started with the W-clone but the glide on the original W-clone build was nothing special.. This I am sure was down to building the wing as I would my powered KF designs with fairly deep steps and steps on top and as you can see on the bottom.. It flew but not brilliantly...at the slope I would compare it to a brick, with a poor angle of glide.. It will be ok in high wind but in light conditions it is poor
Viking60, who has much more experiance on KFm slope and gliders, made some sugestions and taking those on board, and with some ideas of my own, I went on and built the A-clone
What a difference, a nice flat glide, with good speed and manouverability. From a 6 ft high, level, toss I can get 150ft of distance..A winner..
|Feb 18, 2011, 04:08 AM|
I am still messing with the COG and the setup..as the COG and how much control movements you use are critical to getting the best glide from both this and the original Alula design.
In video 2 the glide at the start is good, but it was made using a too far forward COG so at some distance away the nose is starting to drop and I had to bring it up on elevator ..which spoils the glide..so with a better adjusted COG I am sure I can get a nice flat hands off glide with even more distance
|Feb 18, 2011, 04:08 AM|
lines and sketchup files
For both sucessful model builds the layer positioning %wise is the same..35,50,75%
Note But I actually made two KFm9 versions The A-clone includes the elevons in the calculations for the %ages.. The W-clone does not include the elevons for the calculations..
Either way the thin wing, small steps and the multi layer build has worked..both of the clones fly superbly at their build weights, in light conditions, when all that was flying were the super ship racers and DLG models, none of the foamie V wings, and they are both strong, so that ballasting them up for high winds should be no problem
The positions are based on having three steps...and 4 layers
The very top layer4 finishes with its step at about 35%
The next layer3 has the usual 50% step...thats 50% of the whole wing including the elevons..
The next layer2 has a step midway between the 50% step and the hinge line.
The bottom layer1 is the full wing layer..
The usual method involves laminating the layers with the leading edges all lined up vertically, squared up, then sanding the LE into a nice profile with the top of the profile curving up to about the 25% back location on the wing..
This method involves a lot of carving and sanding, but less brain work..Ive been thinking of staggering the leading edges so that less sanding would be required..but remember you cant just move them back as the step location %ages must be as wanted...so some foam will have to be removed from the front before you laminate to produce the stagger..
I will sugest layer1 and layer2 be the full size then remove a bit from the next two layers to stagger to the wanted profile
The CF spar is slotted into the wing by cutting layer2 along the cog line and removing a strip the width of the spar
The A-clone was built with a lauch peg on the spar shown in the pic... Dont use one..your hand positioning using the peg will result in damage to the depron under your nuckles.. Its much better to use a normal grip, fingers on top and thumb below for SAL or discus
EDIT two new additions here with bigger models.. they both go very well at that 25kph wind speed..
The W clone with its balsa fuselage can take a lot more ballast easily
|Feb 18, 2011, 04:09 AM|
reserved for the build4
|Feb 18, 2011, 04:09 AM|
How this one was built plus a minor mod
First a lot of measuring to cut out all the layers...There is no great difficulty, all the layers were cut to full size so when laminated the LE was just a squared off shape..wing tip curves are hand drawn onto paper and then transfered to the foam..The trailing edge of the wing is an arc of radius 34"..this is drawn using string and a pen to get the curve.
Now make a CF spar up with dihedral of 15mm under each tip...I used a 5mm CF tube but have now found some nicer 4mm box CF which will be much better, and will fit in the cutout a treat
Use UHU POR for all the laminating... spread the glue as thin as possible onto both the surfaces to be laminated, let it dry, push together to fix..be warned it sticks like grim death, so always take great care to get the layers or items spot on in place before you let them touch
Layer2 cut the layer at the COG and remove a 4mm strip for the CF box spar..laminate the LE section. now laminate the spar in place on one side only and laminate the rear of the layer..
The depron is thin enough to bend at the center join and the box shape will get it lined up nicely so bend it up and get the two layers glued to the spar.
Now there are only two more layers to laminate so get them fitted... line them up as carefully as possible before using pressure to laminate them
The Tail is 2x 3mm layers laminated, this is stronger than 1 layer, but I have now bent mine so it will still need some CF rod either side to strengthen it up (a Mod needed at the start, rather than a late repair like mine needs) some 2mm CF will do the job taped on..
The tail again was hand drawn at the guide size shown ..it has to be slotted to fit the layers of the wing and slightly reshaped lengthened so it goes up against the 50% step above and below.. Note on the drawing, how far it hangs behind the wing, to workout the length it needs to go up to that 50% step.. Its glued on with epoxy...
Now, the noseblock and top of Fuz...make a block 2"x5" use 4 layers of 3mm and glue this to the front of the wing. To reinforce the block add a layer/strip of thin ply about 1" wide top and bottom of the block.. the strip should go from about 1" back from the front to about 1/2" short of the first top step..the top of the model the ply is capped over with another layer of depron 2" wide going from the front back to the first step
Yes there is no fuzz, but now its time to cover the model with tape and fit the elevons...first cover the elevons, then chamfer them and fit/hinge them to the wing..
When I cover anything I always fix one strip of tape, turn over and fix another strip exactly opposite..working alternate sides give the flattest end result, as does fixing the tape with the depron flat on a surface when you burnish the tape down.
Its a tricky job so take time and do it nice....tape cover the whole wing
|Feb 18, 2011, 04:10 AM|
Making a depron fuzz can be ok but I later found out that there was problems adding ballast.
Not only hadn't I allowed for the extra room needed , but the weight of ballast in a heavy landing, in fact any landing, demolished the lightweight foam fuzz and wrecked the model
I recommend going to a fuzz build using ply or balsa, make it stronger and bigger to allow for adding ballast . . give it an epoxy coating, a bit of weight wont hurt its slope performance, as it needed ballast once the wind got up..
Now the Fuzz.... scratch building....work out the internal width size you need to fit your battery into place or what ever is going to take the most width..mark this width perhaps plus a couple of mm onto your models underside going back from the nose to near the first step, then mark from there, pulling the line into the tail about 1.5" back from the front of the tail.
Now work out your needed depth...
You can now plan and cut your Fuzz sides... they should be cut at the needed depth, back to the pull in point, then tapered to the depth of the tail where they will be pulled into..Its better make the depth slightly over size, then cut down after youve fitted your gear..
Make it deep enough to also act to prevent your servo horn getting hit in a landing
On the A-clone it became obvious that the battery would have to go right to the front of this box to get the COG..even then I had to add 1/2oz of lead to get it good
The fuzz is all made from laminations 2x3mm depron..the pointy nose is loads of layers carved and sanded to shape
The hatch is 2x3mm layers fabric hinged at the front and closed with velcro at the back
Servos are set as flush as possible cut in through the sides and fixed with cool melt adhesive.
The rest of the bits are held with velcro..
control throws and COG
They need keeping small for good flying... elevator +- 5mm and if you fly with the most rearward COG even less works better
...ailerons +- 12mm
.......................COG at 1" for startup better at 1 1/8" and just a touch back from there is looking probable..
That small bit of lead turned out a very fine tuning option.. being able to move it fractions at a time, then marking the spot when it flys its best
|Feb 18, 2011, 04:52 AM|
Next I will be rebuilding the W-clone using exactly the same build method...
Unclear? any question or bits ive missed please post here or pm me direct....dave
Ive also ordered some bungee elastic for some trial at catapult launching
Because these gliders have dihedral built in, you have to take extra special care when laminating the wing.
... I have been laying half of the wing down flat on a glass top table, laminating one half of the wing down flat, a strip at a time, then letting the other half go flat Ive finished laminating the other half.. then moving on to the next layer, doing the same, till all layers are done..
Now I can see Ive forgotten to make sure the relationship of one half to the other was kept correct...each half is nicely flat, but because depron has some give, it is possible to build in some faults...
I noticed it on my W-clone rebuild... when I fitted the flat edges of the fuz to the wing, the rear of the fuz was about 1/8" down and away from the wing, I thought nothing of it at that time, and pushed down the rear of the wing, where its more flexible,fixing it to the fuz, the fuz edges were straight so it should have all lined up..
Only later, after eyeballing the wing did I notice that the wing was showing what appeared a different angle of attack at the center, compared to the tips...this was where the back edge had been pushed down to meet the fuz sides..so at the center it looks to be a bit positive
Luckily the faults ive put in are only tiny...
So be aware that you need to take some precautions. when laminating one half down on a flat surface the "up" end should be propped so it is held flat/square in relation to the other half laying flat on the surface..
Its the same as joining two wing halfs with dihedral..as the glue is drying ,one half is laid flat whist you prop the other half up on a book or something..then both sides get a good relationship to each other..
|Feb 18, 2011, 05:51 AM|
It takes a while to type it all in but most of this build is on here as well starting around post 1879 for the A-clone
The A-clone has gone so well I am remaking the W-clone in the same manor..
Just a note on the A-clones glide...when I built the initial W clone it didnt seem bad, however up at the slope in very low winds it was poor, not useless but disapointing, its glide compared almost identical to a V wing warrior that someone else was using, or rather not using cause the lift was too low.
The high performance big jobbies were just managing to keep up but not going up too well..
The point being ...when the big jobbies were launched they went away nice and flat from a hand throw...the new A-clone has the same sort of glide path flat and speedy, so I am expecting good results on the slope....
Now If only the wind will go in the right direction I will be off..
|Feb 18, 2011, 10:53 AM|
Ive started on the W-clone cutting out all 4 layers, then cutting out for the spar..the spar feels too far forward so I will be positioning it about 1/2" further back in the wing..
note the new spar cut out will now line up with the corners of the construction guide lines, it makes cutting easier...the alteration is easy just another cut along the line and moving the strip produced forward when I do the laminating..
|Feb 18, 2011, 11:46 AM|
The tail is cut 2x3mm layers of 12"x5.5" and the slots for the layers are marked as is the shape..1" of the tail hangs below the layers..and 6" of it is slotted in to line up with the 50% step
NOTE as with the alula the all foam build needs a stronger bigger fuzz to take ballast .. foam alone hasn't got the strength
Fuz sides are cut..30mm deep x11" long, again each will be made using 2x3mm layers..the rear of these will be tapered down to 19 mm where it joins together with the tail, so that the bottom decking will line up with the bottom of the tail once fitted. At the tapered end the depron is tapered/chamfered to fit against the tail better
Decking again made using 2x3mm layers
Nose extension also cut..This is made using 4x3mm layers 3" long x 2" wide...The 2" is over wide to take the fuz sides and it gets trimmed down and shaped later.
To reinforce the nose section two strips of thin ply 1"x6" will be stuck on top of and below the block going onto the wing..the top strip gets capped with more depron to hide it
note in pic2 the spar position is moved back a bit to go between the front corners .. this square tip shape is from the construction guide lines, later the corners are shaped and the spar is trimmed down
|Feb 19, 2011, 05:32 AM|
The W-clone is all laminated and the body built , LE shaped nose etc shaped..I am now covering it
Cut parts weighed in at 103 gms...glued and shaped it was 113 gms with some small parts still to add...glue addded weight, shaping removed some...
The tape covering on the wing has taken it to 140gms (wing fully covered)
Now all covered the weight is up at 155 gms and it is time to fit all the gear..
note COG 105mm back on wing at root... throws as per the alula.... elevator +-5mm ... aileron +-12 to 15mm
|Feb 19, 2011, 11:00 AM|
United States, CA, Costa Mesa
Joined Oct 2009
i have seen some of the most ingenious stuff using the kf airfoils.
i scanned this wealth of material and couldn't find a weight for
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