Chuck Glider discus launches Gambler AG

This is not a free flight glider. I've been dabbling with the "dark side" and my chosen weapon is the Gambler AG from Wright Brothers RC.

Why am I dabbling in the dark side (aka radio control)? Well, there is method in Chuck Glider's madness. The main reason for playing with RC is to learn about discus launching - what it feels like and how bad launches go!

The latest thing in free flight chuck gliders is the discus method of launching, also called tip launching. This is a field of aeromodelling where free flighters have learned from our radio control cousins (not the other way round, as is usually the case ;) ).

The Gambler is a fine model and I've thoroughly enjoyed flinging it about to play with low level thermals. Best flight so far is nearly 3 minutes (in wintery conditions). I have not flown it in good thermic conditions yet and am looking forward to that!

The next stage would be to build a free flight DLG! So watch this space....

Polish Aircraft - Superb Scale Subjects

I've been a fan of Polish planes ever since I watched a full-size Ogar (SZD-45) taking off at an airfield. This is a motor glider designed in the 1970s and is simply hypnotic to watch. No wonder they issued a stamp picturing it (left).

After I had the fortune to fly in other Polish gliders, such as the SZD Junior and Puchacz, I was hooked. They were well made and handled superbly. The SZD-55 is to my mind one of the most beautiful gliders ever.

Now here is a fabulous Polish movie, probably from the early to mid 1960s. It seems to be about wave soaring in the mountains. You need to put the sound on, because the music (Moon River) adds to the effect. Watch out for the footage of an SZD-22 Mucha Standard glider, a model sailplane (at 3:50 minutes in), the Mucha Std being aerotowed by a Gawron (4:40 to 6:30) and the super streamlined SZD-24 Foka glider (8:25).



The Polish aviation industry has a track record of coming up with amazing, ground-breaking and eye-catching designs. PZL means "state aviation works" and no doubt, early on the industry was heavily state funded. After SOLIDARITY and the rise of capitalism, it seems that some of the aviation industry was bought by the European aviation giant EADS. I have never fully understood how the industry is structured and organised. Currently, there seem to be at least two glider manufacturers - PZL Swidnik (who make the PW5 and PW6) and SZD Allstar PZL Sp. z.o.o. (who have a long history in sailplane manufacture).

In the early 1930s, arguably the best fighter plane in the world was the PZL P.11 (photo right). It had these amazing parasol, gull wings. It is not difficult to see why it is a subject for scale modellers, though perhaps not common enough. At that time, the pace of aeroplane development especially in Germany, was very fast and the performance of the P.11 was soon surpassed.

The PZL 101 Gawron was designed in the late 1950s/early 1960s for agricultural and other civilian uses. (Photo left; the tug plane in the video above is one of these). I have not seen a free flight model of it, but it would make a fine subject with those wing tip plates and slightly swept back wings.



The PZL 104 Wilga (left and below) is a fairly common subject for RC models - both scale and semi-scale. With its slightly quirky but cute looks and short take off run, it would make a great rubber or electric free flight model. It makes a good glider tug, full-size and I suppose, as a model.

The PZL 130 Orlik (below) is a very small, ~10m span, 2 seater, highly versatile training plane. It is used by many air forces and the Polish Air Force display team.



The wing planform and the proportions are fabulous (see the three-view below). This would make a lovely model plane.

Unsurprisingly, Poland has produced some fine pilots and aeromodellers too.

Chuck Glider from one 1/16" balsa sheet: Part 5, FREE PLAN!

The final plan for PLAIN SAILOR is below. Right click to save it.

Flying the prototype revealed a weak point at the fin to fuselage joint. This is because the main strength at that point comes from one side of the fuselage, that is, 5mm of 1/16" balsa!

So, I cut the fuselage at the stab and trimmed the fin down, as it was too big. After re-attaching the tail feathers, the glider was much better behaved. I guess the moment arm of the prototype was too long. Compared to the prototype, the overall length (not including ballast) of Plain Sailor is 18".

Unfortunately, I do not have an indoor venue to fly in, but outdoors in the calm evening air I was getting flights of 25 to 30s. I'm sure that could be improved on with more work on the launch and transition trimming. However, this model was not designed purely for duration, but also for the other "tasks" that make up the one-sheet indoor competition, including longest glide and spot landings.

I used a small pea of blu tack on the left wing and a teeny bit of left rudder to get it flying conventional right - left. Take those trims off and it will go straight and level, since there is no stab tilt.

To make it suitable for outdoor, I would suggest gluing a thread on the LE with CA, increasing the dihedral to 2" under each tip and finishing it with 2 coats of sanding sealer with very fine sandpaper in between them. With its light wing loading it could easily fly away in thermal lift. Higher launches would require a decalage setting closer to 0-0, but as has been discussed before, that can introduce inconsistency in way the glider recovers at the top of the launch.

If you build this simple glider, please let me know how you get on.

Vintage "Old Timer" Chuck Glider

I've finished and flown the Bowers glider (see photo left). It ended up at 30g flying weight, which is not amazingly light, but not heavy either. The main aim was achieved though, which was to improve over the Wallerstein 22" that I built too heavy at 50g (see earlier blog, Wallerstein was the "wing donor").

Flying at dusk in cool, still air, I was getting "still air times" of 36 to 42s. I may be able to improve the launch by moving the decalage closer to 0-0 for a more direct up line, but it's working consistently at the moment so I'll leave it alone. CoG ended up at about 60%.

In the air it looks "retro-fabulous" and floats around flatly. In the park a bloke and his son wanted to know where to get one! I explained it was self-built from a 1930s design, but did give them a closer look, explained how the DT works, and let the son have a little chuck.

I reckon it could fly away, so I fitted a simple DT flap (shown in the other two photos). This type of DT is typically made with aluminium foil from a drinks can, but I find balsa easier to work with and keep flat to the fuselage. The orange paint on the inside is an aid to see the DT operate. I use 3M Blenderm(TM) tape for the hinge, a little "fingernail" from a drinking straw to push the flap out and a balsa triangle stop to keep the flap perpendicular to the fuselage side. The airflow does the rest. There is negligible weight penalty with such a DT as the timer and parts add up to little over 1g and it is all in the nose.

There is a small increase in profile drag of course, but that will mainly affect the high speed launch, which is one of the biggest variables in any case! After testing, the flap was cut down to about 2" in length, which was found to be enough to turn the glide from the left hand circle into a straight line, while just about avoiding a dangerous "lawn dart" dive.

That's one problem with drag flaps - too big and the plane can spiral dive hard to the right and die an ugly death on crash landing. If the flap is too small, it willl not bring the glider down from a thermal and it goes OOS.

Personally, I think it is important that the flap turns the glide into a straight line, not a turn to the right, so that the plane exits the thermal.

It's all in the lap of the thermal gods!

Vintage "Old Timer" HLG plans: build pictures

I think this vintage Bowers 20" HLG is going to be quite an eye-catching chuck glider. Here are a couple of build photos.

Left, the wing has been decorated, orange silk applied to the outer break joints as indicated on the plan, and the wing to fuselage joint is glued, aligned and setting.

Right, is a picture earlier in the build. The fuselage has been roughed out, the wing centre joint glued up and drying.

Plans for Vintage HLG or "Old Timer" Chuck Glider

This photo is of a hand launched glider designed in the 1930s by Syd Wallerstein. It qualifies as "Vintage" according to SAM rules. While pretty, the fuselage is heavy pine and so it flies like an overweight hippo. My best flight with it is 55s, which is pretty poor for a 22" span glider. This "fat boy" weighs in at around 50g. The streamer on the nose is an experimental dropping ribbon DT (which actually worked fairly well).

I'm going to re-use the wings on another vintage glider. The chosen design is also from the 1930s and is by Peter Bowers. I guess he is the same aviator who according to Wikipedia went on to work for Boeing and design the Fly Baby homebuilt aeroplane.


I have no idea how the Bowers 20" HLG will fly, but it is an attractive build for various reasons. First, it is the earliest polyhedral HLG that I'm aware of. Second, it seems to be the very early work of Bowers as a young man (possibly while a teenager) before he went on to become such an accomplished pilot and aeroplane designer. Third, the use of silk on the wing joints is interesting and I have a bit of orange silk knocking around.

The tail moment looks a bit short by modern standards and consequently, the tail feathers have a comparatively large area. It should be fun.



Wings of the Wallerstein cut off, reshaped and then sliced into sections, ready for joining into a Bowers wing. One of the advantages of cutting a wing is that you are able to see the aerofoil cross section. In this case, it was clear that more sanding work was required. You may be able to see that I've avoided the high point line.

Peck Polymers takes over Sting

Last month, Sting Aero, was snapped up by Peck Polymers in the USA. Sting Aero was a business run by Len Surtees in Australia (photo, left). It was acquired by Peck Polymers/A2Z Corp in an impressively quick transaction.

I suspect that Len did not make the decision to sell lightly. Tim G of Peck clarified: "Sting Aero Product will become a product line that we sell through our Peck Polymers online store in addition to selling through other dealers". (When you click on the link above, click on "FF Gliders" on the left to see the range).

Peck Polymers should be a great home for Len's product range, which includes the following superb, successful English designs (and I would say design classics):

- BUTTERFLY, by Mick Page (photo, right)

- 2KAN, by Mark Benns

Both are UK Nationals winners. Butterfly kits started shipping soon after the acquistion and other kits are ready or nearly prepared to be offered for sale. The range also includes Len's STING HLGs (various spans and past Australian Nationals winner) and the more recent SPIN UP range of DLGs, by Mark Benns which are all established winners.

Tom Norell of Peck Polymers has confirmed that they will also take over running the annual Heave Ho postal contest. This is a popular, informal worldwide competition originally started by Kevin Brown some years ago. Tom also said:

"We here at A2Z Corp./Peck Polymers hope to continue Len's tradition of high quality competition kits and accessories. If you need something that is not listed yet or have any suggestions feel free to email me directly here at the plant. tomn@peck-polymers.com"

Chuck Glider wishes you all the best of luck!