DG 500 part no 8

The heading should read "Stoned on foam fumes" really its smokey in my Skunkworks and I am not sure about its effect on your health but it has all gone rather well with the foam cutting.





The panels have all been cut to 570mm sections because the foam has a width of 600mm but the lap joint needs to go.


End result unless I cut the sheets lengthways is a new trimmed wing span of a mere 7040mm
which honestly looks about right for the DG500. The mock up with the ventus wings was only to get some ideas.

The new specifications are as follows
Wingspan excluding winglets 7040mm
Area 205.20 dm sq
Loading 56.04 gr per dm sq
aspect ratio 22.8 to 1
estimated AUW 11.5kg
M.A.C. 313.65


This photo indicates how far into the span the shear web goes.
Currently , the panels are being glued together and will then be sanded smooth, next step is to slice a piece out and test fit the shear and joiner box( the dihedral that can be built in and set up when this is glued )back together.
To keep everything in line between the left and right wings the joiner blade needs to be in both boxes.






The weight of the white foam and joiner box/shear web is 1.261kg per wing, resin and glass
will probably double that.




Once the basic wing is assembled,there needs to be a premade channel for installing the servo wiring this will be just behind the shear web.
Then the carbon tows (1x60k goes onto the leading edge) and then the carbon tows for the main spars once this is cured a quick sand and the surface skins can be bagged on.

It looks like the skin layup will be as follows from the outside in
104gr glass straight weave layed straight.
196gr carbon at 45 degress.
UD carbon gr? 2x layers 1.5 mtr out 1x layer to tip.
all wing epoxy is the Epolam 2022 system.
should be very strong .

Cheers for now.
Mike

Shongololo #14 is born

Last night Shongololo #14 was born. This is the second Shongololo for Hannes. His first one has not flown yet, but he has promised that he will be working on it these holidays. So hopefully it will fly soon.
Hannes, Kobus and Tony inspecting the wing after it came out of the mould.


The proud owner with his new baby.

Nice colour scheme on the wings. And even a brand new wing bag.

Mike May's wife makes wing bags. So if anyone wants one, please contact him.

DG500 ELAN part 7

The block of white foam that I started with is a distant memory and that first adrenaline rush as this beauty takes to the sky draws near, so here are more steps in the build which will be posted right until the maiden flight.

The next task is wing cutting and in this regard both Evan and Peter have been invaluable and a great help. I have always cut wings by hand and it was always a hit and miss affair, the last wing I cut like this, was the JART and its very thin profiles made it a nightmare.

But this has all changed, what a revelation ..........my own feather cutter and it works like a dream.

The DG 500 is based on the HQ 3/12 profiles well proven on large scale sailplanes , I cut some

balsa templates for panel planning and

layout , these will be cleaned up and transferred to Formica sheet as templates.












The white extruded foam is cut into 600mm x 360mm blocks which once profiled will be bonded together using Alcoline extreme (tip: wipe the areas to be glued off with a damp cloth)

The foam ceiling boards have a lap joint which needed to be removed.

I had to check if it worked and the wire heat is was ok.. The results far better than I can ever cut by hand.. to master the taper cutting I will use the foam calc program which is on the Jart Blog.



























This weekend the wings need to be bagged or close to that

In the meantime two new challenges (notice I dont use the word problem) have presented themselves.1. the servo tray is exactly in line with the wing joiner box, so running braided steel control cables to the rudder is a problem. The solution is to install small ball bearing pulleys (I have some)and go over or under , or scrap the servo tray and mount the single servo on plywood blocks lower down on the belly , option two probably better but could pose a problem if I ever fit a retract.






2, the elevator servo is to mount in the tail fin(much like the CMP discus featured recently)




this may compromise the strength of the fin . It now makes sense to install the servo into the fin from above, would be a neat solution with equal strength both sides , option two seems more likely unless I can think of any down side.

more later,
Cheers.

DG500 BUILD

Well weekends are for building the big pieces , I tackle smaller components during the week,the weather on saterday kept looking like rain, but I managed to water paper the rudder, tailplane and fuselage , and spray the final coats of 2k white.

In the photo above you can see a dowel through the fuse which makes handling easier,it also acts as a referance marker for the wing joiner tube which needs to be bonded in later.

I went about it like this, and hoped that my initial wing positions on the plug were accurate,I did take as much care as possible at that stage.









The template (HQ 3/12 )was placed on the fuselage and the pilot hole drilled, a thin carbon rod was pushed through and the fin checked for verticle, it was spot on , so far so good.(dont use the column as a referance the glider was leaning a little, check the carbon to the wall top)

Happy so far ,now I check from above (the wooden dowel fitted) the carbon rod on the centre line, the dowel is 90 degrees to the centre line and parallel to the set square, everyone happy.


Next I started with the major shear web which will extend 2.4mtr into each wing , on the Ventus I made the shear web out of a spruce strip with a carbon sock over it and it worked ok, as this span is greater , a different approach is required.



I purchased several sheets of 5 and 6 mm balsa(pity I did not have my scale with) I choose the pieces for stiffness and lightness but just look at the variation in weight. No problem the denser balsa will go inboard the lighter to the outside.





I cut and glued 2x 5mm x 40mm strips grain lengthways , then I cut endgrain pieces from the 6mm sheets. Next I cut out strips x4 of 45 degrees 196gram carbon cloth , lovely stuff this.



The proceedure is as follows onto a mylar sheet on a flat surface , you lay a strip of peelply, next comes the long strip of balsa, I wet this with resin first then lay on the carbon strip. I then wet out the carbon and place the end grain balsa pieces on ,each one lightly brushed with resin.
Next came another layer of carbon , wetted out and then carefully the layup was flipped over , carbon onto the peelply. The same proceedure on the top and closed of with peelply and mylar.

I now placed a piece of wood (straight and flat) on top and loaded on some weight

(you could also vacumn bag this sandwich).
I cleaned up the edges with my belt sander and now have a strong light shear web which will be built into the wings between the carbon tow spars.

The next big step is the cutting of the cores and preparation for bagging the wings.
Until then .

Record Set Sunday

On Sunday the conditions were the best we have ever had at our field, with so much thermal activity about you could stay up with anything, anywhere you liked.

It was about 12h00 when these conditions started. I was actually on landing approach when I picked up a thermal on the western side of the field, which I rode up to speck height. Len launched and started his timer and he too caught a thermal which had him at speck height in minutes. Together we played around , doing whatever we liked. Inverted flying, diving down and riding the thermals back up effortlessly. Len was thrilled because this gave him plenty of stick time on his new Shongololo. Michele Zimmerman also joined us just under the clouds. Eventually he had enough and landed. Then, after 22 minutes Len came in and landed and I stayed up. We started another timer so we could continue recording the flight.

We talked about the thermal duration record and phoned Piet to confirm the time. He told us that I needed to fly for three and a half hours to set up a new SA Thermal Duration Record. (Eish, Man! That is a loooooong time to fly!) That meant that I would have to land at about 15h30. At that time I had been flying for 30 minutes and was getting pretty fatigued. I was so high that I was having trouble seeing the plane. Also, I hadn't come prepared for any record attempt and didn't really know if I would have enough battery capacity for such a long flight.

So Len and I decided that I should rather just set up an official club record of 1 hour.

After an hours flying I came down and landed at 1 hour and 5 minutes.

I was flying my new Vee tail Emoyeni. In the photo above you can see plenty of Charlie Bravo clouds around and with the light winds the thermals moved very slowly, so it was easy to stay with one thermal for ages. The higher you got the bigger they got, so staying up wasn't the problem. The problem was staying focused for so long. For me, a 1 hour flight was enough. To break the SA record will take a mammoth effort of dedication and patience and of course another one of these perfect thermal days.

So there you have it. The Clubs Thermal Duration Record now stands at 1 hour and 5 minutes. Anyone want to try and break it?

Any attempt at breaking it, must be done at the Club of course with at least one other club member as witness.

Invitation to the BERG New Years Eve Fly-Out.

It’s not over Yet !!!.

Just as all the R/C gliders pilots thought that they can pack their gliders away until next year. STOP, come and join us at the BERG club for an afternoon "LAST FLIGHT" of the year. (Until sundown and a friendly gathering of all RC glider pilots.)
Bring your family and picnic basket, gazebo or tent for shade and for once you can leave your stopwatch and spot landing markers at home

A Tsotsi in a Christmas Tree?

Oh yes and don’t forget the campaign and campaign glasses. You will need this when the day’s flying is over and the sun sets for the last time in 2007,

Last year’s Fly-Out was a great successes and for those with bad memory’s (i.e. Alzheimer’s light) here are some pictures as a reminder.

PS. Charcoal Braai firers will be provide if you want to "bring and Braai".

Mike "Clinching his Gasses"

Charl "The Man" & Peter "Rolling a Joint" ??

Pictures do tell stories worth more than a thousand words.

(Well maybe! You make up your own stories!)

DG 500 ELAN

Some more of the build thread on the DG 500 tail feathers .

After cutting the white foam cores the tailplane halves were joined and some lite ply inserts added , these will sit against the tailplane saddle. The leading edge has also been re-inforced with carbon tows (1x60k). The ply-wood saddle was made of two pieces glued together and clamped with a curve which closely matches the actual airfoil , I was lucky it dried with a curve that matched perfectly.

The third attempt at a tailplane seems to be working ,the skins are .8mm balsa sheet bagged on with a layer of uni-directional carbon cloth under neath , the tailplane was sanded smooth and then a finishing layer of 86 gram cloth and finishing epoxy layed onto the balsa.

The ply saddle was sanded and shaped to fit the tail-fin seen here from above.
The inside of the tail was roughed up with a dremal sanding tool to allow the Sika-dur epoxy to key.Carefull alignment to get a zero incedance and it was bonded in, I also used a set square to help set the level , any small adjustments to get the tailplane straight can be made later by sanding.
Clamped and allowed to cure , after which some pieces of carbon cloth and resin were layed up inside to strengthen the saddle to fin bond, at this stage the captive nuts and bolt holes could be drilled and fitted. As I am going to operate the elevator from a servo mounted in the fin once this access is cut, I will be able to work inside on the captive nuts and secure these.
The rudder post is made of ply and cynoed in place and then glassed in with 3 x 60k carbon tows running vertically and finished of with a layer of glass cloth. Into this post the hindges will be glued.

This is what the final glider is likely to look like, yesterday Evan helped me estimate some of the specifications but these are just estimates at the moment.

Wingspan 8 mtrs.

wing area 244.00dm sq

wing loading 56 gr per dmsq at an A.U.W. of 13.5 kg

aspect ratio 26.23 to 1

m.a.c.316.07mm

In the mean time I am out and about procuring needed items such as vinyl logo's , servo's,

heavy duty twisted .5mm copper wire for servo lead extensions, ferrite beads, heavy control horns , nuts and bolts etc. The long wiring extensions will be built into the wings before bagging

so some thought and planning needed for these next steps.

Cheers for now.

Almost Red Hot BERG takes 2nd spot at HTL#7

HTL #7 Group photo

Peter Joffe and I arrived at the Heidelberg field at about 07h30 on Sunday morning to find Derek, Martie and Alan Smith already there discussing where to set up the winch line. The wind was blowing quite hard out of the NW and there was a tractor still cutting one section of grass in the SW corner of the field. The majority of the field had already been cut.

Derek and his sister Che

The farm, situated just a few km form Heidelberg is owned by Derek's sister Che. The field that Che had prepared for us was ideal, with plenty of space and nice short freshly cut grass. To the N and NE there was a ridge of hills about 2 km away. Despite early reservation about downdrafts etc. these hills had no adverse effect on the conditions at all. In fact, they probably had some effect on creating some rather interesting and challenging conditions.

Peter drove down to the fence line at the far end of the field and the measured 250 meters back. And that is where were started unpacking. The rest of the mob continued arriving and it was not long before the teams had established their positions and their camps were set up.In the mean time Lionel and Gert set out the winch and turnaround lines so the teams could get their winches set up.

After the Pilots briefing to once again familiarise ourselves with the Triathlon, Saw Tooth event the comp got under way at about 10h00.

The wind had not let up at all and was blowing a steady 15 knots. There was talk all along the winch line that this was going to be a short event with no lift about. But, it was soon apparent that there was in fact quite a bit of wave lift and almost everyone in the first slot managed to get close to the 8 minute mark. Remember that the Saw Tooth landing system awards higher points for landing on the even minutes. So most pilots elected to land on 8 minutes, rather than risk trying to extend to the 10 minute max.

The BERG team Peter, Evan, Derek & Piet (Almost all Red Hot)

Gert was on the ball all day and kept us informed all the time as to positions of the teams and pretty soon a nice rivalry had started between the teams. BERG was in 1st position after round one. ETB soon took up the challenge and after round 2 they had taken over the top spot. Berg had fallen to 4th at the end of round three. Then Berg started crawling it's way back up and ended the comp in 2nd spot, just 50 points behind, after round 5. There was no throwaway, so any mistake or mishaps cost a team plenty. Teams were made up of 4 pilots and the best three scores for the round were counted towards the teams total.

In light of that, ETB is to be commended for doing so well, because they lost one of their top pilots when Izak fell out with a broken model in round 3.

The BERG team camp

Martie was there with her travelling diner of course and it wasn't long before she had breakfast on the go, ably assisted by Shirley. AAMOF (As a matter of Fact) my tummy started rumbling the minute I went down wind and got a whiff of bacon frying. Hot coffee and bacon and eggs for breakfast was just what the doctor ordered.

Che and her entourage had a constant shuttle service between the farm and the field bringing all the necessary stuff to keep us hungry soles satisfied.

Two big braai's were brought down to the field so we could all do our own braai pack.

The idea was to have lunch after the event, but when it was noticed that there was someone flying a power model on a adjacent field about 1km away we decided to halt proceeding for an early lunch and dispatch someone to go and investigate the rough pilot. Lionel drove around there and found someone flying a 60 size Stick off the public road. The incredible thing was that this guy (a SAMAA member BTW) had stopped at the filed earlier and watched us flying. Luckily he was on 2,4 gig so we didn't have any interference problems.

Derek about to launch Piet's Makula, with Peter checking out the conditions.

By round 2 the conditions had changed a little and coupled with the fact that some had worked out where to get lift the flight times were being maxed. One could launch high in the strong wind and ride the wave for the first part of the flight and then thermal back downwind without getting too far back. This didn't always work and some slots were really short with absolutely no lift at all and 6 minutes was hard to achieve, but then other slots were an absolute doddle.

There were many factors that made this event special. Firstly a new and untried venue, secondly the Triathlon and Saw Tooth event. It is quite challenging and team work is essential if you want to do well. The emphasis is not on the individual at all. A very nice event and a fitting end to a very enjoyable HTL season. Results of the event below.

The eventual overall winners of the Highveld Thermal League are:

Derek in 2 meter

Alan Smith for RES

Paul for Open