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Wednesday, November 28, 2007

DG500 COLOUR SCHEME

The post below this one ,shows the DG 500 mock up, but like most scale gliders they are mostly white and similar looking, its always nice to add some colour to differentiate between them.


I found this photo on the web of DG 505 I think, with lovely red nose and tips so this is the way I will spray mine .


This single seater ASW sports a luminous red nose also popular but finding suitable paint is a problem , its not available in 2k , but nice and visible.

Monday, November 26, 2007

DG 500 build thread

Well the Jart project is complete and waiting for our next slope visit , so its time to carry on with the monster DG 500 Elan, the December break will allow the building of the wings .
Some lovely extruded polysterene foam arrived today and I just had to mock up an 8mtr wing.
Visuallising the final product is an important motivator .The wing will have two 3mtr inner panels and the glider can be flown as such.(in stronger wind and lift) Then there will be 1mtr wing extension outer panels for a full 8mtr span. (lighter conditions and thermalling)

The tape measure is at the 4mtr mark, time to set up my new feather cutter built for me by Peter who hopefully is busy with his Go Big glider.

I have now shifted focus to some of the smaller components like the joiner tubes ,which will be built into the wings. The joiner tubes are constructed around the actual joiner (in this case a hefty carbon blade).

The joiner was covered in plastic tape and thoroughly waxed.













Next I wrapped the left and right halves with 163 gr cloth about two layers thick, to hold it in place(dry) some masking tape was applied.




The cloth was wet out with epoxy and then a wrap of 60k carbon tows were tightly wound around and left to cure.























Once everything was cured I slit one side and removed the boxes, no easy task with the 60k carbon which is rather stiff, I carefully cut the slit with a fine dremal cutting disc(gently).



















The boxes were placed back onto the joiner blade and then a bead of Sika-dur epoxy used to close up the cut, before it cured completely the boxes were slid free.

The sharp edges are sanded smooth , watch out for the carbon it produces sharp splinters(wear gloves). The boxes now get a carbon sock pulled over them and wetted out.










The final joiner box will be bonded into the wing and forms part of the shear web , they came out nice and light and strong.

















Another box is made up of plywood ,over the center of the joiner, this will also be covered in 2x layers of carbon sock. This will go into the fuselage and act as a compession strut between the fuselage sides.





Lastly while the epoxy was drying I resprayed the canopy which had to be water papered down after the second coat of black went all crackle finish, last attempt. It now has my quality stamp of approval.

















Two attempts to bag a stabilizer were just c..p and ended up in the bin, the finish was hopeless and the weight 100 grams to much , I will start afresh on the stabilizer next weekend. Sometimes when things just dont go right its better to drink beer.

Cheers for now.

Saturday, November 24, 2007

A little more Discus CS

The Volksrust weekend has been cancelled due to weather. Looks like I'll just have put the Discus away for another few weeks and get on with some other projects ... like maybe finishing off the ASW28 as well for the next slope weekend. Mike, does 2 x GSAGH = 1 x GBOGH ??

I don't want to hijack the blog completely for the Discus so I'll finish off with some great links for those either building or planning to build one:

Good entertaining and informative review by our very own Lionel Brink (keep an eye on this one regularly as he may give us some photos to include as well). http://www.excelnet.co.za/berg/discus.html


RCGroups Forum with building and flying info, lots of mods and "how I did its". http://www.rcgroups.com/forums/showthread.php?t=604218

The China Model Productions Website - look under the Glider menu
http://www.cmpairplane.com/

Thursday, November 22, 2007

Derek's Shongololo is born


Last night Derek's Shongololo was born. In fact, from the top she is the same colours as the one he previously owned. It's also the colour sheme of the Shongololo on the MGA Logo.


The bottom is different though in that there is carbon showing through between the orange stripes. Nice and shiny too.
This is the 12th Model this year to come out of the Building group and they just keep getting better and better. Can't wait to see this one fly.



Wednesday, November 21, 2007

Discus CS

I obtained a China Model Productions 2652mm wingspan Discus CS arf kit a few weeks ago and thought I'd give you blog readers some feedback on the product. I've seen a few of these Chinese scale models on the Volksrust slopes before and in the right conditions they were really impressive. Although the DG1000 and ASW28 have different branding, I'm sure all these models come out of the same factory in China. I also think the Discus is the prettiest of the models - although owners of the other models will obviously disagree. I've heard some of the guys are putting these little arf kits together in a few evenings but I'm a slow builder and it's taken me a few weeks - but the results are stunning.


The model will probably fly ok absolutely standard but after reading a few rcgroups forum threads I decided to make a few minor modifications. First was to replace the straight 6mm carbon rod wing joiner with a more substantial steel rod which I bent a few degrees to make the dihedral "look right". I also reshaped the rudder to fit better, did a full cockpit and pilot job, recovered the rudder in red solarfilm and put on some red aileron strips.


The kit quality is not fantastic, but more than acceptable for the price. The fuselage is joined with an overlap and the finish looks really smart consisting of basic white coat, applied stickers and then a covering clear coat. The result has a rather "thick and brittle" look and the finish will unfortunately probably crack easily on a hard landing.



But that fuselage shape ... oh very sexy. Blue tinted canopy comes with the outline painted and needs to be trimmed a little to size. The black plastic inner part of the canopy is however a real problem as it is actually too small to fit over the fuselage - but got it all fitting together with a bit of squeezing, stretching and trimming. The wings and stabiliser are built from balsa ribs, fully sheeted with balsa and covered in a very tough iron on covering. The winglets and servo covers are plastic. Control horns and quick links look a bit on the small side but I used them and all control surfaces ended up very firm and positive.















But the best part was fitting out that canopy. Had to cut out the canopy floor for the cutest pilot, found some old multiplex instruments, fitted a compass on top of the instrument panel and was able to produce a great canopy with lots of space left for the radio installation.




One of the unique characteristics of the series of CMP models is the elevator servo mounted in the rudder post. I was a little reluctant at first to add servo weight on the tail but after taking the plunge I'm very happy with the resulting solid elevator linkage with absolutely no slop. The rudder uses a push-pull system - but I substituted the supplied wire with some lighter fishing twine.The model was completed last night.



I used my new Multiplex Cockpit SX radio - setting up all the mixing in a matter of minutes and now just need to balance the wings, set up the CG and we'll be ready for the slope this weekend.

Monday, November 19, 2007

Bird Strike at BERG

On Sunday afternoon the conditions at BERG were very thermic with lots and lots of Swallows about. I was sitting under the shade watching Wolfgang launch. A few seconds after he launched I saw something fall to the ground about 5 meters in front of the winch. My first reaction was that something had fallen off his plane. But what we found was an European Swallow lying on the ground. Obviously it had been hit by the model during the launch. It was still breathing and at first I thought that it was just stunned, but unfortunately it died a few minutes later.
These little birds are so fragile yet incredibly tough. They migrate all the way form Europe. Make that perilous journey and then sadly get struck by a model glider. All that space and still this happens. What a shame!

Michel Zimmerman soon crafted a little cross and we dug a grave and buried the poor little creature. May it rest in peace!

Brits gliding club outing


A lovely way to spend a saterday ,flying and discovering more about full size gliding which has much in common to R/C gliding.








Here are some of my photos taken at the Brits gliding club outing.
A range of gliders hidden away in the hangers from old to modern, some sporting the latest in wing-let designs.
I am sure all BERG members and family who went to Brits enjoyed the day which was hosted by Chris an accomplished full size and model pilot ,who with his fellow pilots made us feel welcome
Thank you .....we will be back.

Sunday, November 18, 2007

Brits Gliding Day. 17 Nov 2007

What is Piet panicking about !! (see picture below)


Take off on runway 20 and land on 02 - A runway is not a One way.


Safely back on mother earth after a thrilling flight.


Wow!! What a day and what an experience it was. On Friday we had high winds, thunder storms with hail, but on Saturday morning the sky was just about clear with little or no wind. A good day for just about any flying activity you can think of.



Chris Adrian, Pilot and Gliding instructor at The Brits Airfeild.

Samba - The Tug

On Wednesday I confirmed to Chris that the number of BERG pilots that were coming on Saturday would not be more than 10. This proved to be reasonably accurate as 9 BERG members turned up for this occasion.

Chris Adrian of the Brits gliding club requested us to be at the Brits flying field at round 11 am. We met the friendly members of the Brits Club and then started to prepare / inspect the 2 x Ka7 tandem trainer gliders for the days flying.



First thing we had to do was to wash the Gilders. Both the ka7 gliders are in the region of 45 years of service but they built them well those days and obviously are well maintained.



Evan and Piet washing the worthy of the sky old ladies (Ka7 Gliders)

Ilma about to go

Once done we pushed them to north end of the 900m tar runway and first off was Ilma in the blue and white Ka7. With Kurt and Chris already in the air, we were waiting for them to land as the Samba aircraft had to double up as tow air craft and in-between for those that wanted to fly the odd flip.

Then it was my turn in the cream and red Ka7, and Chris showed me how to do the pre-flight inspection and then we lined the glider up on the runway. I got in front and with the safety belts tested, we were ready to go. We waited for the tug to turn, hooked up and away we went.


The Samba tug pulled us smoothly along and just before the halfway mark the glider was airborne and a little later the Samba was in the air. Nice thing about the Brits airfield was that there are some lovely grass fields at the south end of the field should you have to abort the launch, but once we came out of the ground turbulence the Samba gained steady height. At 2000 the tug got into a thermal and It was just amazing how quickly the combination of tug and glider gained height when this happened. Chris dropped the tow at round 5600 ft and promptly turned back to relocate the monster thermal we just had.


As we got back into the lift the vario gave a nice kick up to +1.5 m/sec and I was surprised to see how narrow the boundaries of the thermal was. This kept on reoccurring for a while until Chris centered the thermal and then we had a steady climb of +2m/sec to 6500 ft. At this stage Chris gave me the controls which felt very light and responsive. The coordination between ruder and aileron is very important and will require quite some practice.
Chris then demonstrated a mild stall and then we bled off some height with steep turns and finally with the spoilers and then we were lined up on runway 02 for a perfect landing.
All together a 30 min flight of great pleasure, thanks Chris.



By this time some cloud activity blocked the sun and the rest of the afternoon not much lift was around.
Evan and Chris were up next but the conditions was not to good and they were down and landed shortly after the tug touched down. It later on became clear that my flight with Chris was the best of the day and that really is something I won't forget in a long time.

Where's that lift?

Len getting straped in for the ride.

Fortunately the weather held out and Blake, Russell, Mike and Len all got their flights in.
All too soon the day was over and with the Gliders safely back in the hanger we return to the club house for a braai.


Evan just before his flight

Young Blake - Back seat driving

As Evan and myself drove home we were treated to a beautiful sun set, ending off a great day’s flying and I am sure that we will be back again. For those BERG members that could not make it this time, stick around you will get your chance. So watch this space.

O yes, I nearly forget, thanks to Chris and the members of the Brits Gliding Club for a fantastic day. The canteen and ground support is also 5 star.

Piet R
>
BERG

Thursday, November 15, 2007

JART UPDATE

Some before and after photos
the start


the final product.(1st prototype)


The details of the JART control surface hindging and final finishing as part of this build thread, has been moved to the new SA-JARTS Blog (link on the right) as this blog will hopefully reflect all the JART activity in South Africa from now on.
Well its ready to fly,from a lump of blue foam to a sexy soarer,... but time for some reflection , I am sure all scratch builders must get a kick out of admiring their creation prior to that first flight, it is often a long road with pitfalls along the way, but when your beauty takes flight it all seems worthwhile.(especially when it wasnt unpacked out of a box ,but built with your own hands)
I know it gives a deep sense of achievement. Whatever you build and fly ,take pride in your work and enjoy this hobby and all the aspects it has to offer.
The Jart is complete and should fly soon .
Now go build yours I am waiting and impatient.