Mini Topsky DLG

[joe yap]

The tailboom is epoxied onto the fuselage pod. I mounted the wings when doing so, so that I can use the wing to aid checking the tail alignments.

[joe yap]

I decided to go closed loop system using dacron fishing lines. That means that the servo mounting configuration is going to be differeent from the original. I made a new servo mount from laminations of thin plywood.

[joe yap]

I made the control horns from scrap CF sheets. The dacron control lines are routed just like my Predator 2 DLG. I reinforced the control line exit areas on the CF boom with glasscloth.

[joe yap]

My 4 channel orange RX has yet to arrive. So I remove the casing of one of my 6 channel Orange RX and shrink wrap it. It still require a little effort to shoehorn it into the fuselage nose. I have not settle on the RX battery pack yet, but if I can balance the plane with minimum ballast, I can achieve the AUW at about 128 grammes.

I am planning to use 2 photo-lithium cells pack, but still unsure whether it can fit.

[Sunstorm]

I decided to go closed loop system using dacron fishing lines. That means that the servo mounting configuration is going to be differeent from the original. I made a new servo mount from laminations of thin plywood.

where can buy this 'dacron' fishing line?

is it expensive?

[joe yap]

It is definitely costlier than normal nylon monofilament lines, but still quite affordable at around $10-$20 per spool, that comes in at least 200 yards. Of course, it depends on the thickness as well. However, you can ask around for some leftover from some anglers. I'm using 14 lb breaking strain braided Spiderwire. Next time, I'll try 8lbs braided instead.

[pixeldixel]

where can buy this 'dacron' fishing line?

is it expensive?

I have a spool of 15lb spyderwire. Dont waste money. Just get it from me. :smile3:

[Sunstorm]

ok thanks mate

I'll just take some la

kum siah

[msc]

It is definitely costlier than normal nylon monofilament lines, but still quite affordable at around $10-$20 per spool, that comes in at least 200 yards. Of course, it depends on the thickness as well. However, you can ask around for some leftover from some anglers. I'm using 14 lb breaking strain braided Spiderwire. Next time, I'll try 8lbs braided instead.

Hi Joe,
I used this steel braided wire for fishing, cannot remember how much, but I think it's cheap.

[joe yap]

I have the nylon coated fishing steel cable as well. However, they are quite heavy for the job and they are not as slipperly as Dacron fishing lines. Furthermore, the steel cables need to use in conjuction with metal sleeves to terminate the runs, adding more weight and taking up more space.

Dacron is easier. Just tie a loop and apply a droplet of thin CA at the knots. However, you'll need the sharpest scissors to trim it.

[joe yap]

Just bought 2 pieces of CR2 batteries. I roughed out the terminals and end-to-end solder them together before soldering the servo leads. Lastly, I cover it with a strip of heat shrink tube. Turns out pretty neat and fits well in the fuselage nose. I use a small piece of double-sided tape to attach it into the fuselage.

The semi-naked 6 channel Orange ( or not-so-orange anymore ) RX now sits over the battery pack and all up weight is now at 131grammes, 4 grammes under the stated weight.

Apparently, the battery pack weights a little more than what I expected and now the model's CG at at the forward most range stipulated in the manual. That is also probably why the model weighs 3 grammed more than what I anticipated.

[joe yap]

I went out to maiden it this evening. My elevator appeared straight before I gave a light straight and level toss into the wind, which sent the model glided gracefully. The next launch, I gave it a moderate discus launch and turned it into a rocket pitching up and gone pass vertical. I didn't think but my nerves told my thumb to pull 'up' elevator to complete the loop, which saved the day. The model recovered and maintained level flight in a jiffy. Anyway, it was a little windy and I dialled in some down trims for better wind penetration.

Subsequent launches are pretty ok and the model is a real joy to fly, although the lack of aileron controls means that I do not have cross controls. The model is pretty agile and penetrates very well. Upwind turns can be very tight, but keep up some airspeed before doing downwind turns.

Anyway, the field is sickening soggy and I can't really launch the model as well as I would like. After soiling my feet and scandals for about 10 minutes, I decided to pack up and leave.

Overall, I love this little model and would not hesitate to recommend this to newcomer to DLG, who did not want to spend too much time and money on thier first DLG model.

[joe yap]

Today, I brought this little glider for a spin with Adnan and Ronald. My original setup is a little nose heavy, as it'll tend to pitch up during the launch. Adnan kindly offered me some washers, which I attached onto the vertical stabilizer in order to bring the CG aft a little.

Subsequent launches are real joy! After a few more launches, I began to get the hang of it and I can really swing my arm off with this model and sent it as high as the bigger brothers do. The wings held up against my intense launches, which eventually started to loosen off the throwing peg. However, nothing breaks and I kept getting respectable height, launch after launch.

There's a point to take note of these DLG that does not have ailerons. During the launch, if the model climbs with the wings bank to a steep angle, the rudder may require max throw to roll it back. As such avoid launching it with excessive bank angle. Also, if the model is climb angle is too steep to be level off with whatever 'down' elevator input, the next best thing to do is to input full 'up' elevator to execute a tight loop and exit at level flight, before it bleeds off too much airspeed.

As what Adnan has mentioned, this model loses out to their bigger brothers and aileron wings, on wind penetration. If you flown it downwind, do not try to stretch the glide when you want to bring it back to you flying upwind. A big advantage of this model is that, at this weight, you can literally dive it down from height, level it off at hand catch it even at higher airspeeds! Yes, you can even try to catch it at faster landing speeds that you normally won't want to try with bigger ships. This feather weight glider will stop instantly when it touches your hand without the risks of breaking anything.

In conclusion, This model is great fun for its value, and I highly recommend this model for any newcomer with a budget who wants to try DLG.

[James Lee]

Hey Joe,
I'm flying the Super Mini Topsky. It comes with Ailerons and that is a 25g weight penalty. The glide ratio is... challenging.... One thing I find is that this model needs rudder input and you pay a big height penalty if your turns aren't coordinated.

It's a good sized model to start on DLGs though. Learn how to DL the G.

The line you're referring to is either Spectra or Dyneema, or gel spun polyethethylene lines. Dacron is a much much older technology and you less likely to find it in our fishing shops now. I would caution about going with too light lines for 2 reasons. One is knot strength, you never get 100% knot strength, even with the specialty knots fishing fans use. So 8# is less than that. Second reason is spectra/dyneema is very thin and can either cut into your control horns gradually or the lines can get knicked and weaken. These are things fisherman using spectra are aware of, but may be new to flyboys. I'm building a 1.5m DLG with springed surfaces and realised that once a string pops in flight, it's bye bye birdie! I'm using 20# spectra and it is still very thin and weighs nothing.

[joe yap]

I can't comment on the aileron version, but at least my R/E version has earn its keep.

Today, I took out both my Mini Topsky and my old 1.5m Predator 2 for a spin. My full house P2 does have the penetration and distance coverage advantage over the MTS, however, the latter has one distinct advantage over the bigger brothers.

With the large amount of dihedral and big rudder, this midget can circle very tightly in small bubbles of thermal. I achieved my best flight time on my MTS at 9 minutes flat on my last launch, just before the sky started to rain. This was achieved by working on several small pockets of thermal which are not so significant to larger ships.