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Gliders => Slope Soaring => Topic started by: AndyB on November 20, 2020, 17:09:20 PM

Title: Build attempt / learning process
Post by: AndyB on November 20, 2020, 17:09:20 PM
Is this a good place for a build log, or should it be in a different section?

I've started to build a monster, and have had some good results, well good enough to share.
Title: Re: Build Log
Post by: billscottni on November 20, 2020, 17:29:55 PM
If the monster is a slope model this is fine
Title: Re: Build Log
Post by: AndyB on November 20, 2020, 17:53:03 PM
It's definitely for the slope.

This is all a bit new to me, technique and materials so it is not perfect, but highly enjoyable.

I started by cutting out the fuselage profiles and then using a hotwire to get the rough shape. I then drilled some rods into either end to add strength and make a sort of rotisserie arrangement for later. Filed the rough shape further and then sanded.
Title: Re: Build Log
Post by: AndyB on November 20, 2020, 18:03:17 PM
For the vertical stabilizer (and eventually all other surfaces) I made a 4axis hot wire cutter and got to work. it was a bit tricky because of the root and tip difference in size and the length of it the kerf (hotwire burning size) took some attempts to get spot on. Anyway got that mounted and faired it in.
Title: Re: Build Log
Post by: AndyB on November 20, 2020, 18:27:00 PM
I added some filler all over as there were some gaps in the foam, and faired again. Then covered it in lovely brown packing tape to create a barrier for the next stage.
Title: Re: Build Log
Post by: AndyB on November 20, 2020, 18:31:56 PM
Next was wax and then two layers of glass weave, resin and peel ply. then bag it all up and let sit for 12hrs. Then another two layers of glass, resin and peel ply. some wrinkles on the compound curves, but all in all it was pretty neat.  To finish it off I unbagged it and tried to get it as hot as I could for the next 24 hrs. I didnt remove the peel ply until it had cooled back down because of the risk of delamination.
Title: Re: Build Log
Post by: AndyB on November 21, 2020, 07:46:07 AM
Finally, I marked up the hatch, cut it out and poured in some acetone. With a bit of poking and pulling the packing tape detached and came right out without any messing. Was actually really surprised as I was expecting this to be a quite tedious and messy.
Title: Re: Build Log
Post by: rogallo on November 21, 2020, 08:25:09 AM
A Jart,
     a very fast model and quiet a bit of history. I have a "kit" for an epp one, if anyone wants it.

The lost foam method is sweet and not bad for the second or third build.

Keep up the posting and the good work

Ralph

Title: Re: Build Log
Post by: AndyB on November 21, 2020, 09:25:41 AM
Yea Ralph,

I'm wondering how I will ever land it. Actually thinking of the wings ATM and whether to not go will full wing ailerons and split into flaps and ailerons.

Another question I have is how to finish a balsa laminate, how to seal it for finish and paint?

Title: Re: Build Log
Post by: rogallo on November 21, 2020, 10:01:47 AM
Full wing aileron, can use them as flaps on landing would be my preference.

Bill Scott is the man to give you advice on the finish for the wing, Are you planing on film or glass and paint?


Keep up the good work


Ralph
Title: Re: Build Log
Post by: AndyB on November 21, 2020, 10:36:44 AM
Full wing aileron sounds nice and simple to me, just wanted to check as I saw some other builds adding flaps. I can always try it at another stage when I get more comfortable with the process.

re the balsa finish, I have no idea. It doesn't seem like it needs the strength of glass, but it would definitely make a nice finish if I used mylar when bagging it.

I did a test stabiliser; foam core and 0.8mm balsa skin, with a kevlar live hinge and some carbon tow and its really strong. I would prob not use this one as the finished product as I got PU glue on the hinge line and wasn't too happy with the opening to free it up, But this is all learning and testing to me.

BTW also bagged for this process.
Title: Re: Build Log
Post by: billscottni on November 21, 2020, 12:07:41 PM
If you have the ability to bag the best finish would be lightweight glass cloth (25gsm). It's only to give you a surface to paint won't add much strength or weight
For landing you could set up full span ailerons as spoilerons which I believe is what John Pearson uses on his PSS stuff
Title: Re: Build Log
Post by: AndyB on November 21, 2020, 13:44:13 PM
Bill,

Would that be on top of the balsa or instead of the balsa?
Title: Re: Build Log
Post by: billscottni on November 22, 2020, 16:50:25 PM
on top
Title: Re: Build Log
Post by: billscottni on November 23, 2020, 16:23:39 PM
Lots of good stuff here: https://www.youtube.com/user/evanevshaw/videos
Title: Re: Build Log
Post by: AndyB on January 18, 2021, 09:33:45 AM
Those videos are great, thanks.

I finally got my spars from the slow boat and have the right wing sheeted and left one nearly complete, pics coming soon.

I am struggling to get my hands on mylar sheets, can anyone point me to a supplier or an alternative to mylar?
Title: Re: Build Log
Post by: Fred on January 24, 2021, 16:59:44 PM
Hi Andy,

Lindinger have some (from R&G) about 10€ a sqm.
If you need smaller sheets, Amazon and all that. I only know shops in France really but depending of the usage, PVC sheets will do the same.
Title: Re: Build attempt / learning process
Post by: AndyB on January 26, 2021, 12:32:20 PM
I was planning to use it for covering the wings in light glass and get a smooth finish. But in the interests of seeing if my wing design will hold up, I think I will plough ahead with covering it with some easycoat I have spare (horrible green that cheap and was never used).
Title: Re: Build attempt / learning process
Post by: AndyB on February 10, 2021, 17:45:26 PM
While I'm immobile recovering from hip surgery I finally have some time for some "progress" updates. Again this is all a learning process for me and I know I am probably doing stuff wrong with wrong materials in the wrong order, but I feel it's the best way for me to learn, and I'm having fun doing it anyway.

I guess I'll start with the wings, there are 4 sections with one main spar that tapers from 12mm to a 10mm and then a small spar or 8mm to stop rotation. I used a small Dremel CNC to cut the ribs and root out and the 4axix hotwire for the core.

The ribs, spars and foam core were glued together first and then finally assemble, I added some carbon tow, because why not, and peelply at 45° for the hinge. Then all covered by balsa sheet and vac bagged.

Happy with the results, but I doubt these will be the final wings, but I should be able to fly with them.
Title: Re: Build attempt / learning process
Post by: AndyB on February 13, 2021, 13:03:22 PM
Next was to trust my measurement and cut out the flap to the peelply, space for servo and run the servo wires to the root.

Title: Re: Build attempt / learning process
Post by: rogallo on February 13, 2021, 16:30:00 PM
Hi Andy,
   keep up the good work. Just a few questions, where did you get the carbon wing joiners and the vacuum bag and connector, I have a set of wings to bag here sometime if I can track down the parts.
Cheers

Ralph
Title: Re: Build attempt / learning process
Post by: AndyB on February 13, 2021, 16:41:13 PM
Hi Ralph,

The spars are actually fibreglass tubes from Ali express  :-X. I did want to use carbon but decided on the cheaper alternative for the first set of wings as I would be learning and wouldn't feel bad if I screwed it up and had to throw them away.

The vac bag connector is from easy composites; https://www.easycomposites.co.uk/tbc2-through-bag-connector, I did a bit of a bulk order so saved on postage. I also got the air hose coupler from the local motor factor.
Title: Re: Build attempt / learning process
Post by: AndyB on February 13, 2021, 16:53:26 PM
I made sure the wings were correctly aligned with a laser and holes were bored through the fuselage. I made exact copies of the wing root ribs for where the wings join the fuselage and made a fillet with epoxy and silica, was actually really worried about this part but saw a good video from Reed on this process and it turned out quite neat.
Title: Re: Build attempt / learning process
Post by: Kevin O'Donoghue on February 13, 2021, 21:34:41 PM
That's an absolutely super build so far. Well done! Can't wit to see the finished product. No pressure!!!!!!!!
Title: Re: Build attempt / learning process
Post by: AndyB on February 15, 2021, 10:39:36 AM
Thanks Kevin, I'm really happy with the progress so far and excited that it might actually be able to fly.
Title: Re: Build attempt / learning process
Post by: AndyB on February 20, 2021, 09:20:16 AM
I got some primer on the fuselage and the good/bad thing is it reveals all the low and high spots, so plenty of filling and sanding still to go. It's coming together now. I still need to figure out how to attach the horizontal stabaliser, at the moment I have a sleeve that it fits into. I am thinking of either just bonding it in or creating a hole or two on the ventral side of the fuselage to allow access for a retaining screw/s.
Title: Re: Build attempt / learning process
Post by: Kevin O'Donoghue on February 20, 2021, 19:20:16 PM
Looks really good. You'll have to go into mass production!
Title: Re: Build attempt / learning process
Post by: AndyB on March 23, 2021, 12:45:36 PM
That primer just revealed how uneven the glass shell alone was, I had to acetone it all off and got some west 407 on followed by lots of sanding. I had red and black spray cans from when I added some colour to my weasel, these went on well.

I did the electronics and fixed the mpx wing connectors into place, so now the wings slot on nicely and the servos are connected. I made a pretty rough pushrod with balsa, piano wire, thread and glue, works great. I got it all programmed and even added braking and elevator mix.

Next is to cover the wings and horizontal stabilizer. Last is to bond in the horizontal stabilizer, I wanted to make this removable, maybe in my next build attempt or when I make a new horizontal stabilizer.
Title: Re: Build attempt / learning process
Post by: rogallo on March 24, 2021, 09:49:59 AM
Andy,
  looking good. I would put the battery in front of the regulator as the kinetic energy will ensure the battery hits the reg and causes a big fire, or not!

Just saying

R
Title: Re: Build attempt / learning process
Post by: AndyB on March 24, 2021, 10:34:51 AM
 ;D preparing for a crash already. I really hope I can keep this intact for at least a couple of flights.
Title: Re: Build attempt / learning process
Post by: billscottni on March 24, 2021, 16:36:30 PM
Keep the distance between the end of the wood and the Z bend as short as possible, or you could get flex in that steel rod
Title: Re: Build attempt / learning process
Post by: AndyB on March 24, 2021, 17:51:40 PM
Keep the distance between the end of the wood and the Z bend as short as possible, or you could get flex in that steel rod

@billscottni , good advice, thanks
Title: Re: Build attempt / learning process
Post by: AndyB on March 27, 2021, 13:39:53 PM
Got the wings covered in black, not the greatest of finishes, but functionally fine. Bonded in the horizontal stabilizer, balanced the wings, port was heavier than starboard.

Did center of gravity, although measure for cog is 60 to 68 from LE, I took it at 64. Also made the suggested changes to my ghetto pushrod, thanks Bill.

All I need now is some fair winds and hopefully my leg is ready for some cross field trecking for the recovery. :-X
Title: Re: Build attempt / learning process
Post by: billscottni on March 27, 2021, 19:58:39 PM
Looks good. If we EVER get any sunshine, cover the wings when it's on the ground they'll get warm! There's a good reason so many full size are white ;)
Title: Re: Build attempt / learning process
Post by: AndyB on March 29, 2021, 14:30:58 PM
 :-X It seems I have made a poor choice in wing covering colour. Anyway, if we get some sun it might iron out the defects in my covering.
Title: Re: Build attempt / learning process
Post by: billscottni on March 29, 2021, 16:21:22 PM
the number of days we get where it would be an issue are limited
Title: Re: Build attempt / learning process
Post by: AndyB on July 12, 2021, 14:17:09 PM
I am still waiting to get this in the air, but the wind at the weekends has not been from the right direction. If anyone is heading up to Killakee (or other location) at any stage please let me know, as I would appreciate a lookover and moral support when trying to fly it.
Title: Re: Build attempt / learning process
Post by: Fred on July 12, 2021, 17:23:53 PM
It's beautiful, so it will fly! :)

Same, if anybody fancy a trip to Kilakee, I'm your man! (for moral support, and beers too :) )

Title: Re: Build attempt / learning process
Post by: Spanner on July 12, 2021, 17:37:43 PM
Hi Andy,
Looking good, nice job on fuselage for first attempt at using glass.
Weather forecast for Wednesday afternoon and early evening is looking good for Killakee. Wind might be a little light but worth a trip up if forecast holds. I should be available unless work gets in the way.

Joe 
Title: Re: Build attempt / learning process
Post by: Fred on July 12, 2021, 20:05:28 PM
Free Wednesday evening if you guys are :)
I would not mind some light warm wind :)
Title: Re: Build attempt / learning process
Post by: AndyB on July 13, 2021, 17:24:51 PM
Great, see you there tomorrow afternoon/ evening
Title: Re: Build attempt / learning process
Post by: Spanner on July 14, 2021, 13:36:27 PM
Hi Guys,
I hope to get to Killakee around  5.00 pm see you there at some point.

Joe
Title: Re: Build attempt / learning process
Post by: Fred on July 15, 2021, 17:30:31 PM
Want to see someone happy?
Look no further!  :-*
Title: Re: Build attempt / learning process
Post by: billscottni on July 16, 2021, 13:58:31 PM
I take it, it flew well then ?
Title: Re: Build attempt / learning process
Post by: AndyB on July 16, 2021, 14:52:07 PM
Yea it flew and I got it back in one piece, but it was flying a bit arse down. I checked the incidence the next day and all was good so I reached out to the designer and he said to just bring the CG forward a bit, on the plans, he gives an 8mm range for CG and I had taken the middle of that. That's hopefully going to sort it out and I'm ready for take two now. The only problem is waiting for a westerly
Title: Re: Build Log
Post by: Joyplanes on July 20, 2021, 17:32:39 PM
It's definitely for the slope.

This is all a bit new to me, technique and materials so it is not perfect, but highly enjoyable.

I started by cutting out the fuselage profiles and then using a hotwire to get the rough shape. I then drilled some rods into either end to add strength and make a sort of rotisserie arrangement for later. Filed the rough shape further and then sanded.

That's a nice built, where do you get that foam?
Title: Re: Build attempt / learning process
Post by: AndyB on July 20, 2021, 21:46:50 PM
I actually got it from a neighbour who was have exterior insulation installed. It was 300mm closed cell styrofoam and was stronger than others I tried. for example, it resisted me poking my finger at it where other foams seemed to compress and collapse. I don't know if it's the best stuff to use, but it was free and worked well for me.
Title: Re: Build attempt / learning process
Post by: rogallo on July 21, 2021, 10:40:44 AM
Andy,
  looks great, cannot wait to see it flying on the hills.

R
Title: Re: Build attempt / learning process
Post by: AndyB on July 21, 2021, 11:01:08 AM
I've got Mt Leinster for the 28/29 in the calendar, see you then