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Global Cirrus Glider ARF Review

Marc Webster reviews this superb first polyhedral ARF. Marc finds the instructions to be superb, the wing the strongest of any polyhedral he's ever flown, and all-in-all the model to be an ideal first glider.

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Introduction

Great covering scheme!
Great covering scheme!
Wingspan:2m (78.75")
Wing Area:680 sq. in.
Length:48.5"
Functions:May be 2-channel, or 3-channel with optional spoilers
Servos:Global Cirrus CS36 (3)(not incl.)
Transmitter:Multiplex Royal Evo 12
Receiver:Berg 6-channel
Battery:4.8V 1100mAh NiCd
Available From:Global Hobby Distributors

So you want to learn how to fly sailplanes, but just donít have the time or the required skills to build a sailplane from scratch? Well then I have the perfect glider for you; the Cirrus 2 meter glider ARF. Over the years, Almost Ready to fly models have really come a long way, but most were of the powered persuasion. Unfortunately, the sailplane ARF choices were quite limited and many just did not fly well. I have to be honest, it has been a long time since I have flown a polyhedral sailplane, but I have to say that Global did a great job and the Cirrus 2M is a fantastic glider to teach newcomers the sport of soaring.

Kit Contents

The Cirrus arrived at my door undamaged in a large shipping box. When I opened the box, I was surprised to see that Global had also included 3 standard size cirrus CS-36 servos for me to use in the Cirrus 2M ARF, as well as a high start for launching (not included in the normal kit). All of the main parts were individually bagged. The first thing I noticed was the complex covering scheme which was very well done. As with any ARF, a few of the parts had some wrinkles in the covering, but that was to be expected since the temperature and humidity fluctuated from where it was covered to where the ultimate end user (myself) lives. A quick once over with a Monokote iron and all was well again. My father was so impressed with the quality of the kit and price that he too bought a Cirrus, and we built them side by side.

Assembly

Wing

Minor Adjustments with Tip-Panel Joiners

I started with the wings. The instructions were well done and included a picture of every step. The assembly of the wings went just as planned with one minor complication. The wing assembly consisted of two mid panels and two tips that were glued to make a one-piece, 2-meter polyhedral wing. When joining the wingtips, the instructions mentioned to glue the wood joiners into the outer end of each mid panel. Then after the glue dried, glue the tips on at the desired dihedral angle. The problem I ran into was that the tip joiner box had enough slop that the joiners could be biased up or down. This had the potential to actually a good thing, as the slop would allow the builder to adjust the root ribs to match up if needed. Unfortunately, I did not do a 'dry run' to test fit the panels, and when I glued my joiners into the mid panels, one joiner was biased too much in one direction, so the root ribs did not line up perfectly. It was really not that big a deal, just a minor annoyance.

Had I chosen to glue the joiner and tips on at the same time, I could have biased the tips as needed to match everything up and then let the glue dry. However, special care would have been needed to ensure that the joiner was installed with equal amounts of joiner in each box.

Center Section Wing Joiner

The center sectionís wing joiner was aluminum and there were shims included in the kit just in case there was any slop. Unfortunately, my kit had one joiner box that was tight and one that was a bit sloppy. I had to cut the shim in half so it could be used on just one wing panel. My fatherís kit did not have this problem, and his wing joiner fit just fine without any shims.

Optional Spoilers

The wing also had two spoilers that were pre-installed but taped down. The cirrus could be built with or without the spoilers, or even upgraded to allow spoilers at a later date. I decided to use my spoilers since they allowed the ability to spoil the lift when it came time to land or to bring the glider down out of a strong thermal. The spoilers were held down by individual rubber bands. To actuate the spoilers, the servo pulled two lengths of fishing line that drew the spoilers open. When checking the spoilerís actuation, I noticed that they closed very slowly and sometimes not all the way down. I decided to add a second rubber band to each spoiler, which allowed the spoilers to fully retract flush to the wing surface. The small rubber bands used in Dental braces work great.

Fuselage

The Fuselage was very well made. The sides were light plywood and the nose was shaped hardwood rather then balsa. The hardwood nose was nice since it was very strong and added a bit of much needed nose weight.

Adjusting to Fit a Larger Sized Receiver

The instructions showed the installation of 3 servos; elevator, rudder and spoiler. Each servo was to be installed individually in three separate pre-determined bays within the fuselage. Under the wing was the Rudder servo. In front of the rudder servo was the spoiler servo and in the next bay was the elevator servo. In front of the elevator servo was the bay for the receiver and just in front of the receiver was the bay for the battery. I ran into a small problem when I discovered that the bay set aside for the receiver was too small for the receiver I intended to use. My receiver was too tall and protruded out above where the canopy would sit. If I had cut a large relief in the underside of the canopy, it would have allowed me to use my current receiver, but I decided to go another route. I decided to install both the rudder and spoiler servo side by side in the bay that would normally only contain the spoiler servo. I then installed one single servo for the elevator in front of the two. In the bay that was to be set aside for the rudder, I installed my receiver. This configuration allowed me to move the weight of two servos as far forward as size would allow, and allowed me to install my lighter-weight receiver under the wing, close to the CG.

Even with this modification, I still needed to add a bit of nose weight to balance out the Cirrus at its suggested CG. To lessen the amount of weight needed, I hogged out an area into the rear of the hardwood nose block. This took a bit of time, but it was well worth the effort since it allowed me to fill the area with a slurry of epoxy and lead shot.

Built-In Ability to Adjust the Tow-Hook

The Cirrus also included an interesting way of allowing the builder to adjust the tow-hook as needed. On the underside of the fuselage was a square slot. The tow-hookís installation plate consisted of a blind nut mounted to a wooden plate that had a square piece of plywood that fit within the square slot in the fuselage. To adjust the tow-hook position, all I needed to do was loosen the hook's jam nut and slide it to the desired location and tighten it in place. This was a great little innovation and a nice feature to have, as the tow-hook could be moved back which allowed me to experiment with moving the CG rearward as flying skills progressed.

Tail

Flight Performance

Global Hobby was so kind to also include a High Start with the review kit that I could use to launch the Cirrus. However, I decided to attempt my first flights with a standard 12 volt winch. After arriving at the flying field, I performed the standard range check and took the time to check that all my control surfaces moved as they should. After a couple of hand tosses to trim the elevator, I was finally ready to launch the model. My clubís winch is mainly used to launch all composite high performance Thermal Duration models with wingspans around 3 meters. Needless to say, the winch was optimized for much heavier models. With this in mind, I decided to just tap it up to test out the wing's strength. The first launch went just as planned without a hitch.

On the first flight I decided to just check all the controls for sensitivity and to see what would happen when the spoilers were deployed while still up high. It had been a while since I had any stick time on a polyhedral model and I was expecting the model to respond slowly to rudder inputs. I tried 360 degree turns with alternating circling directions to see how quickly it would change from one turning direction to the other. Boy, was I surprised. The cirrus turned on a dime. Soon it was time to land and I decided not to bother with the spoilers since the landing speed was quite low.

I spent the rest of the day testing to see just how much load the wing could take during launch as well as trying to find some lift. The wing on the Cirrus was by far the strongest Polyhedral winged glider I have ever flown. I still tapped it up the winch a bit, but as I reached the apogee of the launch, I stomped down hard on the pedal, dove and zoomed off the winch just as I would on my all-composite Thermal Duration glider. I have had many flights with the cirrus that were well in excess of one hour and have been very happy with it.

I also tested out the High Start that Global included and it worked very well.

Teaching Beginners

Just last week, a young kid (Andrew) and his mother showed up to see what we were doing. I immediately took Andrew out to the field and spent some time showing him how the glider worked on the ground. We then launched it and I handed him the transmitter. After about four flights I could just stand beside him and tell him where to go. If we would have had more time I would have been able to talk him through a landing. Hopefully, he will show up this weekend for more instruction.

Conclusion

All in all, the construction of the Cirrus was very stout and its assembly could be performed by someone who had never had any prior experience with any sort of R/C model. This was mainly due to the very well written and illustrated instruction manual.

I have to say that this is by far the best Polyhedral 2 Meter glider I have flown. Being an ARF was just icing on the cake. I bring the Cirrus with me to the field every time I fly my sailplanes, just in case someone new shows up and is interested in experiencing what soaring is all about. I personally feel that every club should have a Cirrus at the field at all times to give any interested people a chance to fly.

Discussion

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Old Sep 22, 2005, 08:18 PM
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John Gallagher's Avatar
Lindenwold, NJ, USA
Joined Dec 2000
3,143 Posts
What's the RTF weight of the Cirrus?
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Old Oct 31, 2005, 11:52 AM
Swedes don't grow on trees
Jonas Leander's Avatar
Sverige, Stockholms Lšn, Stockholm
Joined Jan 2001
496 Posts
Another question: Does the wing end up as a one-piece or two-pice wing when finished?

/ Jonas
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