2015 ... 40 plus years on.

If you have a model, either electric or glow, that you feel has such a great setup that it would be beneficial for others to know about, then tell us about it here!

Moderator: Committee

User avatar
uplink
Posts: 829
Joined: Fri Nov 16, 2007 9:51 pm
Location: Ravenshead Notts

2015 ... 40 plus years on.

Postby uplink » Wed Jul 01, 2015 2:34 pm

Gosh, that really did take a lot longer than anticipated.

You know those kind of projects that sound like a good idea at the time, but then appear to drag on and on... thankfully,
though, it is now complete.

Yes, with my shed finally erected, insulated and lined, I've at long last been able to start using this new 'building facility'
- and to use it to put together something that's a little more aeronautical than the recent acres of matchboarding and felt shingles.

Indeed, with plans drawn up, it was now action stations and into the new shed with sheets of balsa and ply - along with
all the 'other menagerie of things' necessary to magic a plane into existence.

The project was to produce an updated version of a much liked 'Old Gal' from my Colwick days.

Way, way back in the early 1970's (when dinosaurs still had the upper hand), I was working my way through my fledgling RC days at
Colwick Racecourse with the Trent MFC. It was then that I designed myself a 10 foot, pod and boom style glider.
She was about my 3rd or 4th RC design and was launched 'bungee & fishing line' fashion and was given the aspirational name: UpTern
- ambitions, no doubt, born of those sleek little birds.

Uptern with experimental wings Low low res.jpg

UpTurn in her original Orange Solarfilm livery, at Colwick Racecourse about
1975 and here sporting some 'experimental' slightly undercambered wings.
(click on pics to enlarge and on Browser's 'go back' button to return to article)

Yes, I recall back then making a smoke generator to try and study the flow over various aerofoil shapes and from this
experimented with 3 sets of wings for Upturn with different aerofoil sections.

08-09-08 Goosedale  002-2Low low res.jpg

2008 at Goosedale and that's UpTern on the left - now in red Solarfilm
- with an original set of wings, though at this stage they'd been modified
to include ailerons and flaps.

Anyway, now some 40 something years on and with well over 2,000 flights to her credit, UpTern is still flying and
doing so better than ever - though I admit, the last 3 or so years she has done so sporting some non original wings.
And about 12 years ago she was weaned off of the 'bungee & fishing line' and modified to be shown 'the ways of the electric force'.

It was only recently that I came to realise - of all the planes I've flown over those decades, Uptern has been
- and today remains - my favourite plane to fly.
So, having realised this, as she is now past her 40th year (and not surprisingly, if scrutinised, starts to look her age)
I decided to build a new 'Uptern 2015' fuselage (new wings having been built just last year). I based the new fuselage closely upon the original's
dimensions - hoping to preserving those original good flight characteristics - whilst at the same time trying for a slightly
more 'rounded and elegant' aerodynamic profile - the original was 'slab sided balsa' rounded off at the corners, by as much as
internal triangular fillet strips would allow.

The 'agreeable behaviour' of her flight I attribute largely to the length of the fuselage boom, putting the 'tail feathers'
a touch further out from the C of G than is normal - a boom which was made of what was 'the new thing' at the time:
a section of a fibre glass fishing rod. On the new fuselage the boom is being updated to be made of 'the thing' of the present time:
carbon fibre - a 12mm diameter tube of it.

Because I wanted the new fuselage with an approximately round cross section, I decided the best method for building was
where you cut through all the round bulkheads to form, as it were, a 'flat cleavage plane' so there were some straight edges
to rest on the building board during initial construction. (A technique I recall learning back in 1963, when I building a Keil Kraft
Luscombe-Silvaire - an interesting Scale, Free Flight kit.... which unfortunately had a concealed method of wing retention,
and this was responsible for a crash on its maiden flight).

DSC00776Inital build inverted Low low res.JPG

The build gets underway - first the bottom half, built inverted.
(click on pics to enlarge and on Browser's 'go back' button to return to article)
Now THAT'S a thermal.

User avatar
uplink
Posts: 829
Joined: Fri Nov 16, 2007 9:51 pm
Location: Ravenshead Notts

Re: 2015

Postby uplink » Wed Jul 01, 2015 2:43 pm

DSC00801Then start to add the top half Low low Res.JPG

...... and then the top 'half' begins to be added.

DSC00804The trickiest part Low low res.JPG

And here, the trickiest part under construction.

The fairing that holds the wings in place was the hardest part to design and construct.
This needed to accurately follow the curve of the wing, have its own curves in 2 dimensions,
be easily removable and yet be strong enough to keep the wings in place during high G manoeuvres.
It has 2 fore/aft running carbon rods which also at the rear end act as retaining pegs into holes in some stout plywood.
At the front can be seen a nylon bolt which locates into a captive nut - don't think I'll trust it to a nylon bolt though - I'll find a steel replacement.
Now THAT'S a thermal.

User avatar
uplink
Posts: 829
Joined: Fri Nov 16, 2007 9:51 pm
Location: Ravenshead Notts

Re: 2015

Postby uplink » Wed Jul 01, 2015 9:04 pm

DSC00829Topside almost done Lowlowres.JPG

Topside of Pod section almost done.





DSC00839Race to the finish on the bottomside Lowlowres.JPG

And bottomside planking racing to the finish
Now THAT'S a thermal.

User avatar
uplink
Posts: 829
Joined: Fri Nov 16, 2007 9:51 pm
Location: Ravenshead Notts

Re: 2015

Postby uplink » Tue Jul 07, 2015 7:51 pm

DSC00859Fin & Rudder LoRes.JPG

Rudder & Fin take shape fastened well to the piece of ali tube which is a snug fit in the end of the Carbon Fibre Boom.

I used a piece of ali tube, into the end of the CF boom, because I wanted a tight epoxied fit of the tube into a 'blind hole' in the vertical hardwood rudder post - and I didn't want to be drilling side holes in the CF tube for the servo wires exit - the hole for the wires would have had to be close to the end of the tube to make threading the servo wires easy and a hole near the end of the CF tube would have weakened it considerably - see below re using a Ferrule.

Plus I don't like making more carbon fibre dust than I have to.

This is a T tail model and so the fin has to take the tailplane flight loads - hence the hardwood rudder post and the focus on getting a good boom to rudder mechanical connection.

DSC00869Securing to CF Boom LoRes.JPG

Carbon Fibre Boom is added courtesy of epoxy and a securing method I've been using for years:
multistrand wire wrapped around the two objects you want to stay together and then twist the ends and get the twist to pull up really tight by using some pliers to get more torque in there than your fingers could achieve - then epoxy the wire all around and push epoxy well into the objects you're binding and there you are - a tough, tight epoxy/metal matrix.

You may notice I've also bound the end of the CF tube where the ali goes into it, so forming a ferrule.
I've found in the past that CF tube can be split by sideways loads applied inside the tube right near the ends - as will be imposed by the ali tube and its attached Fin, in this case.
The ferrule (of wire and epoxy) prevents the CF tube splitting.
Now THAT'S a thermal.

User avatar
uplink
Posts: 829
Joined: Fri Nov 16, 2007 9:51 pm
Location: Ravenshead Notts

Re: 2015

Postby uplink » Tue Jul 07, 2015 7:54 pm

DSC00890Balsa Skin and in with the Servos LoRes.JPG

On with the rudder's Balsa Skin and in with the rudder and elevator servos.

DSC00895All coming together now LoRes.JPG

All coming together nicely now.
Now THAT'S a thermal.

User avatar
uplink
Posts: 829
Joined: Fri Nov 16, 2007 9:51 pm
Location: Ravenshead Notts

Re: 2015

Postby uplink » Tue Jul 07, 2015 8:06 pm

DSC00904Mock Canopy of Kingspan Building Foam LoRes.JPG

A 'Mock Canopy' made of Kingspan building foam cut and sanded to shape - this stuff works so well and can give a really nice sanded object - sands even better than balsa.

The final surface can then be covered in solarfilm or, as I like to do, just harden up the surface a little and fill in any little blemishes with a mix of polyfiller and a 50/50 mix of water and PVA glue - add the liquid sparingly as you mix to end with a consistency of thick but still runny custard - then brush on fairly thick coat all over the foams sanded surface.
Leave for 24hrs to dry really well then lightly sand with fine glasspaper.
Then paint, spray or cover with solarfilm.

DSC00905With Toughening skin applied LoRes.JPG

Toughening coat applied and left to dry well.

I may one day have a go at making a proper see-through canopy - but this will do OK for now.

...hope the wife doesn't want that mixing mug back - the left over polyfiller/PVA mix has set solid!!
Now THAT'S a thermal.

User avatar
uplink
Posts: 829
Joined: Fri Nov 16, 2007 9:51 pm
Location: Ravenshead Notts

Re: 2015

Postby uplink » Mon Aug 03, 2015 9:51 am

DSC01180LoRes.JPG

Crumbs!
Needed to hollow out the foam canopy a little to allow the flight battery a little more room for air to circulate and keep it cool.
Once 'target depth' was reached, I smoothed the bottom of the hollow by an inlay of balsa sheet.



DSC01206LoRes.JPG

Underway, with my very low tech way of finding the incidence setting of the tailplane relative to the wing: good, stable supports and a tape measure.
Having first done this on the old Uptern model, I could set up the new one's tailplane so it would be correctly tilted - kind of important in making sure the trim wont be too far out during those crucial, first couple of seconds after launch.
Both old and new Uptern models use 'all moving tailplanes' rather than an elevator, so the angle of the whole tailplane relative to the wing is varied by the elevator servo - this does mean that the tailplane incidence is down to you setting up the servo position correctly and not down to the usual: 'well, that's how it sits on the fuselage, so that's got to be the correct angle'.



DSC01252LoRes.JPG

And there she is - at Goosedale, just prior to her first flight - the only original 1970's part is now the tailplane!
At this point, I'd just had a flight with the wings and tailplane on the old fuselage - here seen in the background - just to 'get my eye in' ready for the new plane's maiden test flight and that 'brown trouser' moment ....
Which - big sigh of relief - went very well indeed. And the new Uptern is noticeably better - definitely felt more buoyant. Though, to my surprise, acted a touch tail heavy, despite getting the C of G the same as on the original plane.
I put this down to the better streamline fuselage shape and the fact that the large, aerofoil shaped nose must now be providing some lift forwards of the C of G so tending to push the tail down.
Still, just a few clicks of down trim and all was fine.

She's now had 4 flights and I am well pleased with both the gliding and aerobatic performance.
Yes, very well worth all those hours working on the drawing and building boards.

So, if you haven't built something for a while, you really should give it a go - it really can still be very satisfying.

And that now means, I only need to build a new tailplane and I have myself a totally new plane !
Now THAT'S a thermal.

User avatar
uplink
Posts: 829
Joined: Fri Nov 16, 2007 9:51 pm
Location: Ravenshead Notts

Re: 2015 ... 40 plus years on.

Postby uplink » Sun Aug 30, 2015 10:15 am

I know a couple of guys have been interested as to how the wing tips were made, so here's a pic of one during construction.

Wing Tips Lores.JPG


Simply made from 1/16inch sheet balsa - the trailing edge and outer edge of each tip's upper and lower surfaces were glued and then rolled around a big cardboard tube which came from a roll of carpet we had. The balsa pieces were held in their rolled position with masking tape until the glue dried and then the wing tip rib was added.

Note - the concave (hollowed inwards) side needs to be covered with iron on film covering BEFORE this above build/bending process - because, if you've ever tried it, you can't easily iron film onto an extreme concave surface.
Now THAT'S a thermal.

User avatar
uplink
Posts: 829
Joined: Fri Nov 16, 2007 9:51 pm
Location: Ravenshead Notts

Re: 2015 ... 40 plus years on.

Postby uplink » Sun Apr 09, 2017 4:18 pm

And so, about 18 months on from the first flights with 'Uptern 2015', in which she proved herself to be both a reasonable thermal machine and an excellent and exhilarating aerobatics glider, the radio gremlins decided to strike!

Pulling full up at about 100 feet, during an aerobatics flight, I found I no longer had any control - the failsafe suddenly activated: the throttle cut and the last servo positions locked in.

Failsafe has a kind of comforting ring to it, don't you think .... if things fail, then all is safe..... well, no, it doesn't mean that at all.

In this instance it meant the elevator, having been full up before loss of signal, stayed at that deflection and caused Uptern to go into a series of stalls, each getting closer and closer to the ground. ... still no radio contact.... come on, give me back some control.

But radio connection failed to restore and the final 'free flight' stall resulted in a nasty, very nose first 'meeting with the ground' - Ouch!

And so it was back to the building board....

IMG_0127LoRes.JPG


And looking at my original plans, there were a few bits I would build differently this time - like this time I'd have a go and reverse the brushless motor so it would be using a rear mounting rather than front mounting - and I'd make the canopy in a planking style balsa build, rather than as previously, which used a carved foam block build... the foam suffered a bit from finger nail dings during operation.

IMG_0310LoRes.JPG


The motor goes into position fastened to a removable ply box (box with the motor attached, I decided would be removable from the plane via 4 small screws). Rear mounting of the motor means the 3 wires don't have to be routed close to the rotating outer of the motor - they can be a bit too close for comfort in the narrow noses to be found in some gliders.

IMG_0313LoRes.JPG


Planking gets under way.

IMG_0551LoRes.JPG


Battery support tray added - this tray is removable via 4 screws, should access be required to the ESC which is mounted below it.

IMG_0548LoRes.JPG


The surviving rear fus meets the new fus front section.

IMG_0589LoRes.JPG


The planked version of the canopy gets underway.

IMG_0720crop bright LoRes.JPG


And there she is - back to an Almost Ready To Fly state.

Though at this point I found I still needed to add a little tail weight for correct C of G.

I needed to reduce the weight at one of the wing tips to get the lateral balance back ok.

I needed to iron and twist out a couple of slight warps in the two flaps.

And needed to add some patches of 'female' velcro on the fus section which clamps the wings in place, as they have always been prone to a little sideways drift through the fuselage slot.

...that's all done now, so just need the wind to stop being quite so blustery and see if she still remembers how to fly.



Oh yes, I have also changed the radio receiver, though the range and functionality on the one that did the damage, tests excellent in all respects.

I do believe, though, I now know why the radio problem probably happened.

On a glider such as this one, as the wings are presented to the fuselage for the 2 aileron servos and the 2 flap servos to be connected up, there is quite a bit of excess wire to allow this connection before the wing goes into its flight position - and here's the rub - that excess wiring festoon gets stuffed pretty much anywhere it will go.... and in the fateful flight I suspect the festoon ended up cloaking the receiver antennas, which lived in the same small compartment! ... a good re think has thus occurred on the relative placement of antennas and wiring and other metal and carbon fibre objects within the rebuilt plane.... hope I've got it right this time.

And so, back in the air...

IMG_0009Uptern2015 LoRes.JPG
IMG_0010Uptern2015 LoRes.JPG
Now THAT'S a thermal.

Puffin
Posts: 625
Joined: Sun Nov 18, 2007 2:16 pm
Location: sherwood

Re: 2015 ... 40 plus years on.

Postby Puffin » Mon Apr 10, 2017 6:34 am

Very good read fantastic build most enjoyable :D

User avatar
uplink
Posts: 829
Joined: Fri Nov 16, 2007 9:51 pm
Location: Ravenshead Notts

Added a short video

Postby uplink » Sun Dec 23, 2018 3:39 pm

.
.
A short video of Uptern 2015 doing a few gentle aerobatics in 2017:


Best to click on the text link as it allows you to play full screen size - clicking on the Photo link and you get a really small screen size displayed.

https://www.youtube.com/watch?v=xTK0OzYioG4





Now THAT'S a thermal.

Puffin
Posts: 625
Joined: Sun Nov 18, 2007 2:16 pm
Location: sherwood

Re: 2015 ... 40 plus years on.

Postby Puffin » Sun Dec 23, 2018 3:50 pm

Our time Fly’s


Return to “My Models Spec & Other Info”

Who is online

Users browsing this forum: No registered users and 1 guest