GliderIreland - Ireland RC Forum - Flying Model forum in Ireland
Gliders => Thermal / Flat field => Topic started by: joe on February 12, 2012, 14:01:25 PM
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So after the bones of a year off gliders I returned to the workshop. I started to make a plug for a Quark 2m fuselage then found a bunch of materials I bought for another project and decided 1. Fred's quark is perfectly fine the way it is as a built up kit and 2. to start building some DLGs :lol:
Design is standard Drela Supergee type affair.
Cut two set of cores on Friday. Took a few goes to get the file and the settings right but am fairly happy with the results.
Hot off the cnc
(http://www.gliderireland.net/forum/images/uploads/joe/photo1.JPG)
Trimmed, shaped and sanded
(http://www.gliderireland.net/forum/images/uploads/joe/shaped.JPG)
Packed the otherhalf and small one off to Engerland for a few days this morning so plan is to get stuck in and have them in the bag by this evening.
Mylars next....
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If you heard a strange sound off in the distance earlier that was probably me screaming. Left my wings on the cnc table while i was cutting mylars. Computer was asleep. I pressed a button to wake it up and turned back to the mylars. Heard a sizzling and turned to see one of my wings melting! Long story short I was down a wing and not very happy :!: :!:
thankfully i cut two sets. :cry: :cry:
(http://www.gliderireland.net/forum/images/uploads/joe/damage.JPG)
Mylars cut
(http://www.gliderireland.net/forum/images/uploads/joe/mylar.JPG)
Making composite fabric. Kevlar and fibreglass
(http://www.gliderireland.net/forum/images/uploads/joe/photokev.JPG)
Ready to layup the wing
(http://www.gliderireland.net/forum/images/uploads/joe/layup.JPG)
Finally in the bag
(http://www.gliderireland.net/forum/images/uploads/joe/finished.JPG)
That was a lot of work. Should be a lot quicker next time as I have the mylars and kevlar ready to cut and i know what i'm doing a bit more(kinda) :wink:
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Looks good Joe :clap:
Pod and boom fuse? :?:
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Hey Frederic.
Yeah pod and boom. Have a few booms. Will start fuse today.
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By the way, what are the specs? Size, profile?
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1.5metre
Area: 21.75 sq.dm
Loading (at target weight): 11 g/sq.dm
Target weight 250grams
Profiles: AG 45,46,47
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Looking good Joe. Your not doing the vacuum bagging in the kitchen are you?
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Thanks Alan. Did the layup on the table as the wife and small one are away. Then moved to another room for the bagging.
Fuse pod in the parting board ready to go. First side tomorrow hopefully. Got to keep going. If i stop it'll go back on the shelf for who knows how long!
(http://www.gliderireland.net/forum/images/uploads/joe/fuse_parting.JPG)
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Keep it going Joe! you are not allowed to stop now!!! Love the wings, nice job
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I’m not sure exactly how you’re making these wings, :?: presumably by vac-packing the composite onto the foam?
But that must mean you have a vacuum pump, yes?
Er …..west/ north winds for next few days Joe. It was a bit wet on the Big L yesterday :cry: . Are you gonna join me there before the weekend? :D
K.
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I’m not sure exactly how you’re making these wings, :?: presumably by vac-packing the composite onto the foam?
But that must mean you have a vacuum pump, yes?
Thats a yes and a yes Keith.
Wonder if that wind is north enough for the North slope tomorrow? I'll be in touch.
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A-Haaarrr! :?: I have a task that would benefit from a vacuum pump. You see while you were ‘away’ last year,....... er,..... well just follow this thread and you’ll see what I mean
http://www.gliderireland.net/forum/viewtopic.php?t=1172&postdays=0&postorder=asc&start=30
I had been thinking of just using an “I” spar, but if you have a vac pump maybe you could help an old friend out to both “I” spare and glass the wing? ‘Belt & Braces’ perhaps but very strong wings non the less.
Let me know what time you what time you want to go tomorrow, :D if you want to go that is. :?
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Thanks JP. I'm goin, I'm goin! :D
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Be happy to help Keith. We'll have a chat and formulate a plan.
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So fuse has gotten resin and will do the laminate this evening when the resin has gelled.
(http://www.gliderireland.net/forum/images/uploads/joe/fuse_resin.JPG)
So the wing.. Well the aim was to make something that is useable and I'm pretty happy that I've achieved that. It's far from perfect and I can see a few things I'd change straight away. Having said that it's not a millions miles away from the one I bought last year. They are a lot of work to make but the finish is really nice. Next one should be a lot quicker. :D :D
Here it is out of the bag. Needs to be trimmed
(http://www.gliderireland.net/forum/images/uploads/joe/wing.JPG)
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First half of the fuse mould glassed. Now we wait.
(http://www.gliderireland.net/forum/images/uploads/joe/fuse_glasssed.JPG)
Wings sanded and trimmed. 140grams. Not bad for first go.
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Nice work Joe.
I made something similar a few years ago, but went without flaperons and increased the wing dihedral to give me a R/E ship and made the pod using the lost foam method rather than going thru all the hassle of moulding for a one off.
I'll dig the model out of the garage and take some pics...... when my back stops playing up and I can actually get out of the house! :!:
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Sorry to hear you back is giving you trouble again Bill.
They are a nice project alright. I have/am considering a R/S version. It would need a least 10degrees of dihedral i reckon to be responsive with rudder only. Thats a lot of dihedral! It would look a little extreme. Polyhedral looks better to me. But you would have to reenforce where the outer panels join which would add to the weight lost by not having any servos :?:
Well I have 4 booms and will have a fuse mould soon so I can make a straight one and a poly one! :D
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So half of the mould and the canopy is now done. Getting there
(http://www.gliderireland.net/forum/images/uploads/joe/mould_half.JPG)
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Hi Joe,
Whats the order of wing layup? Does the mylar go on first or after the cloth?
John.
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Hi John.
The mylar is there to give a smooth surface so you have foam, fibreglass/carbon etc then mylar.
When you are doing the layup you actually do it onto the mylar and then set the core down on the bottom mylar and place the top mylar on top making a sandwich with the wing core inside and all that goes in the vac bag. It gives a really nice smooth shiny finish like a moulded wing.
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I assume you peel the Mylar off when the resin has set?
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You assume correctly Alan. Very satisfying it was too. Thankfully :D
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Hi Joe,
The penny has dropped. By the way does the mylar conform properly to the airfoil in all directions ie does it stretch in all directions or is it rigid and behaving as a sheet of paper would(creasing at wingtips).
Thanks John.
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It's very rigid John. Think laminated business card type rigid. Leading edge to trailing edge is fine as are rounded corners like the DLG wing. It won't conform to a square tip or crease would probably just crush the corners a bit. Depends on how much vacuum you are pulling i suppose?!
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Hi Joe , very interesting build.
You are a young man of many talents.
The wing came out really well and at 140g it is a good weight , my blaster 2 is 138g flying weight and I acheived this by using 2 servos in the pod. This gave me more forward weight and reduced the amount of lead I had to use up in the nose.
I also went rudderless (6.5g) and used a spring pull elevator(7g).
I also shortened the boom by 22mm, my launch heights improved and the plane turns alot better in low tight thermals.
This all helped to elimate adding weight up front to correct the CG plus I have a plane that thermals alot better in low light lift.
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Hi Richard.
So far so good. The idea was to build something that was at the standard of an entry level DLG and then try build better, stronger, lighter as I go.
138grams flying weight? just for the wing right?? similar weight but, your blaster wing will be twice as strong as my wing :D
interesting stuff Richard. I'm not going crazy trying to keep the weight down but i will save it where it's easy to do. Want an average build as a reference and i need to leave room for improvment! :D
Mould's done. Came out fairly good. One side is good and the other needs a little touch up. Can see where i went wrong. Lesson learned(hopefully)
(http://www.gliderireland.net/forum/images/uploads/joe/mould_parts.JPG)
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Very nice indeed Joe !
I had some ideas on a dlg a few years back but it really is difficult to work on such simple yet complex planes.
I had thought about cutting the wing in half (on the length) and milling out triangular sections and then fitting the spar and sandwiching back together and glassing, I reckoned you could save 30g plus and improve the wing strength.
My old blasters are used on the sand dunes and sea walls around the North Coast, as you live beside the sea you will have hours of fun with your proto type. But be careful you mite get hooked on HLG :wink:
Keep up the good work.
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You're right Richard they are simple but not easy to work with. The cores are thin and delicate and it's a bit of work just to get something fairly standard like mine but, it is satisfying when they come out usable.
Plenty of small coast sites here when we get some sort of easterly alright.
Was kinda planing on getting hooked to be honest. Wanted to do a lot more thermal flying this year. Was flying yesterday in the field beside me and caught a few small little thermals. More like neutral air really. Have a really old hi-start/up-start type affair that an auld guy gave to me years ago. It's standard household bungee cord and is fairly shite. It only stretches about twice it's length so launch height was about 20 metres :-( Am waiting on some rubber from hobbyking. If i can get a decent launch height i'll get into using it i'd say. Then it'll be time to build a TD/F3J type affair!
Have a few machines that should work ok off the hi-start. Between them and the DLGs I should be good.....for now :)
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Looking good Joe! :clap: :clap:
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Getting there Fred. Getting there. :wink:
Mould is touched up. Need to sand a few little spots and wax her up then she is ready for use.
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As promised a couple of pics of my version of the SGII. Finaly managed to get out to the garage and put it together for pics
(http://www.gliderireland.net/forum/images/uploads/billscottni/SGIIa.jpg)
Plan view of my version. Wing is cut from blue & pink foam, carbon spar and then vacuum bagged. This was my first attempt, so there are a few dry spots!
Fuz is a lost foam moulding and the fin and tailplane are again bagged foam with carbon spars
(http://www.gliderireland.net/forum/images/uploads/billscottni/SGIIb.jpg)
This shows the amount of dihedral needed for the rudder/elevator version, from memory, I think it's 12 degres each side
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12 degrees sounds about right Bill. I plan to do a rudder/elevator version. Different airfoils though as the supergee airfoils are designed for flaperons and are a little unusual on the topside because of that.
So the most important questions. How does it fly? and then what weight did she turn out?
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I never weigh my models Joe, so I don't know the weight. As for glide, it flies fine. My attempts at discus launch have been less than spectactular though!
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I usually don't weight mine either but they usually are slopers. With something like a DLG weight plays a much bigger role.
Yeah the launch definitely takes a bit of practice. Been a while since i flew one and they weren't great then either.
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Hi Joe,
Looks like dancing to me. Just think Bruce Forsyth in tights and give it socks. I would like to try. Any chance of foam blanks?
John
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Hi john.
As long as i can just think Brucey, not actually wear the tights! :D
If it's EPS you're after then yes. Blue foam is my personnel stash. 8-[
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You still working thru that car load I brought down a couple of years ago Joe? :o
I still remember the squeaking for nearly 4 hrs driving down :?
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Am indeed Bill. Trying to use it sparingly. And what a lovely sound it too. Is it still available from the same place?
:wink: :wink:
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Is it still available from the same place?
:wink: :wink:
Not sure Joe, haven't bought any in a while either. I can find out for you?
John knows of a different supplier in Antrim, that would be worth checking too.
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Would appreciate it Bill. I think i remember John saying that supply had dried up?!
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Joe,
He has 3 sheets left. Will let us have them at same price as last, which I think was £11