Great Planes’ ElectriFly CIRRUS SR22 TURBO EP ARF

By Bob Noll

Great Planes has just introduced their SR22 Turbo, a scale model of Cirrus Aircraft’s SR22T. First let’s take a look at the full size SR22T to give you an idea of why Great Planes may have selected this beautiful airplane for its ElectriFly kit.

Cirrus Aircraft

Cirrus Design Corporation was founded in 1984 with a dream to design and build affordable airplanes that deliver greater control, more comfort, and unprecedented levels of safety.

The SR20, with its composite construction and advanced aerodynamics, was awarded FAA Type Certification in 1998. It incorporates flat-panel, multi-function display technology and state-of-the-art safety innovations, including a final level of protection known as the Cirrus Airframe Parachute System™ (CAPS).

Today, Cirrus is the world’s leading innovator of single-engine, piston-powered aircraft. In fact, for the last five years, the SR22 has been the world’s best selling airplane in its class.

SR22T

The SR22 is one of the more capable single-piston transports on the market, providing its pilot and three passengers with the highest levels of efficiency, safety, and comfort. Turbocharging increases speed at high altitudes; a “weeping wing” ice-protection system improves wintertime dispatch rates; and the X Edition package offers buyers a slew of interior and exterior upgrades aimed at enhancing style and comfort. A top-of-the-line, fully equipped SR22 GTS sells for just under $700,000. (Ed. Note: Guess Bob and I have different definitions of “Affordable”.)

The full-size aircraft is 26 ft. long and 8 ft.11 in. high. Its wingspan is 38 ft. 4 in. Powered by a 315 horsepower Continental TSIO-550K engine, the Cirrus SR22T uses only 1267 feet of runway to climb over a 50 ft. obstacle from takeoff. The gross weight is a generous 3,400 pounds allowing for 1,052 pounds of useful load. The airplane carries 92 gallons of fuel providing a maximum range of over 1,100 miles. Maximum cruise speed is about 225 mph.

These are good performance figures for this airplane class. Even more important, the airplane’s turbocharging lets it operate up to 25,000 ft!

Great Planes’ SR22T Kit

While the Great Planes’ Cirrus SR22T probably won’t perform equally as well at 25,000 ft, I was still very eager to open the box and take a look when the kit arrived. Every major component as well as the accessories where carefully packaged in clear plastic bags for protection. Cardboard separators in the box insured that the components would not be damaged from transportation. I was absolutely astounded when I opened the fuselage bag and found one of the best examples of a fiberglass fuselage that I have ever seen.

Yes, I did say fiberglass since this was the only practical way for the beauty of the fuselage to be captured in an ARF. Of course, Cirrus had the same problem and uses a very similar construction they call “composite”.

The external painted finish was outstanding with no visible seams. Wing fillets were accurately placed and blended perfectly into the wings. The canopy locating pins and retention magnets were already installed as were the tinted windows; saving considerable work for the builder.

The pre-painted wheel pants are also fiberglass and of excellent quality with no seams showing. The wings, complete with ailerons, the horizontal stabilizer, elevator and rudder are covered in white Monokote®. The wings and horizontal stabilizer have silver Monokote on their leading edges to simulate the “weeping wing” ice protection system on the full-size Cirrus. However, the RC pilot may not be comfortable flying the Great Planes’ Cirrus in known icing conditions as that might be a little too cold and wet for RC flying.

The aileron hinges were already permanently installed. A carbon fiber tube is used for the wing tube which provides strength and minimizes weight. The accessory package is very complete with all of the hardware needed to complete the model without a trip to the hobby shop.

The decal sheet is very complete with sticky back vinyl rather than the water transfer type.

Great Planes recommends these items for the Cirrus: RimFire .10 brushless outrunner motor, the Silver Series 35A Brushless ESC, the APC 10x7E propeller, an ElectriFly T-Rex 11.1 volt, 2200 mAh lithium polymer battery and four ElectriFly ES50 Nano servos. These were all used on this aircraft.

Construction

As I do when evaluating kits, I made notes in the instruction manual when I found a discrepancy or if I thought additional information would help the builder. In general the manual is very complete with many good photos.

One of the first suggestions is about pulling the aileron servo wires through each wing panel to the center. Strings were carefully threaded through the ribs and taped in place to simplify the process. However it seems like the holes in the ribs were not large enough for the connector to pass through unless the connector was in the same plane as the string. The servo connector continued to get caught inside the wing.

The manner of attaching the string to the servo lead, as shown in an instruction book photo, was not the way to go. Tying the string around the connector several times making sure that the connector could not move out from inside the string finally allowed me to get the servo extensions through the wing (photo 4A).

Use a No. 32 drill to clean out the anti-rotation pin holes in each wing half. Use hand power only on the drill bits to make a snug fit. Once cleaned out, the wing holes fit the pins well.

The wheel axles are two different sizes so be sure you get the two axles for the main gear in the correct place.

While the instructions ask you to remove the covering from the center of the stabilizer, this was already done on my kit. Apparently Great Planes decided to do this for you. I believe was a very good decision. This eliminates the possibility of weakening the stabilizer where the covering is cut away, something that has doomed many other airplanes when the stabilizer folds in two while airborne.

Make sure that you spend time to be sure that the stabilizer is properly positioned before gluing. That means paying attention to its alignment with the wing. I had to sand considerable material from the bottom of the stabilizer slot on one side to achieve the parallel alignment required. The manual had very good photos showing the alignment process. Check the Sport Aviator article Building an ARF Trainer for more detailed instructions on this process.

The manual (page 10, item 7) has a very important statement with sketch. That is to cut away the covering on both top and bottom of all hinge slots. This will ensure that the CAA will properly weep into the hinge slot insuring that the hinge is properly glued in place. Be sure to use the straight pins as shown to properly locate the hinges. See the Sport Aviator article Installing Mylar Hinges in the Flight-Tech Section.

The nose gear fairing is an important part of the looks of this airplane but it is very thin and difficult to position on the strut. The manual recommends using CAA glue but I decided that there had to be a better way. So I used Zap Goo® which would provide me with some working time and which would not become brittle as CAA does.

I stripped the threads in the nose wheel steering collar while being sure that the set screw was tight on the strut. Simply tapping the hole for a 4-40 socket head screw fixed the problem and allowed easier access to the screw with an Allen wrench. Better yet, be careful when tightening this set screw and do not strip it in the first place.

Speaking of the nose gear, I placed the screw-lock connector for the nose gear in the inner hole in the servo arm, not in the outer hole as the manual suggests. I did this because my experience tells me that we usually have too much nose wheel steering and I was right as later taxi tests proved.

The main landing gear easily bolts into the wing mounts. The fit was perfect.

CAUTION – DO NOT INSTALL THE PROPELLER WHEN SUGGESTED. Keep the propeller off of the airplane until the very end when you are doing final balancing and even then do not tighten the propeller nut. Many accidents with electric airplanes happen in the workshop when setting up the model.

I decided to paint the seats in the cockpit interior a light tan but could not find a pilot that looked correct in this small airplane so I did not use one. (Ed. Note: The Williams Brothers 1/8 Sportsman Pilot bust fits well intro this airplane. I did not use CAA to install the interior because its application cannot be controlled very well. I used Zap Goo again for this step.

The decal application is a bit tricky since the decals are very large and extend from the front cowl to the rudder in one X-shaped piece. I thought about cutting them into separate pieces to simplify the job but decided to give it a go in one piece.

YOU MUST USE THE SOAPY WATTER TECHNIQUE AS DESCRIBED. Another pair of hands would help here but I did it with only my two hands. You can too if you are careful and use plenty of that soapy water. Check out the Sport Aviator review of the Liberty for more information on this decal application technique.

You will have to refer to the picture on the box for proper decal location. Be careful to use the correct wheel pant decals since the two for the nose gear are slightly smaller. Don’t forget the two decals for the top of the wing tips which don’t show up very well in the photos.

The Cirrus scale paint scheme doesn’t provide high visibility for a grounded pilot. But then why should it as the full-size need not be that visible from the ground? For the RC pilot however, the addition of some bright colors to the bottom of the wings and stabilizer would help.

Great Planes factory installs all the fuselage mounts for the internal equipment. The plywood is strong yet “hollow” for lightness.

The recommended equipment is all a perfect fit and made assembly very easy.

Don’t forget to add the cooling outlets on the fuselage bottom. Not only are they scale but they are a “must” for proper motor cooling.

The Cirrus has some very complex wingtips. Fortunately, these are not only scale but are factory installed. They also look great on the airplane.

Preparation for Flight

The instruction manual is very clear regarding those steps needed to insure a successful first flight. These include;

• Centering the servo output arms – Use the sub-trim feature on some radios to get this correct.

 

• Centering the control surfaces: Get as close to neutral as possible by adjusting the mechanical clevises and then make the final adjustments using the sub-trim function. Make sure that the transmitter trims are in the neutral position before setting the control surface centers.

 

• Roll the airplane on a hard surface to insure that the nose wheel is properly set.

 

• Checking for the direction of all control surfaces: I highly recommend that you do this while standing BEHIND THE AIRPLANE since you will be less likely to have incorrect aileron direction by doing this. Taking off with the ailerons working backwards will make that first flight extremely “interesting” and likely very short as well.

 

• Set the control throws according to the recommended chart. I was please to see that the chart provided angular measurements as well as linear measurements. I always use my handy deflection gauge to measure angular surface deflections since it is most accurate.

 

• Balance the model at the location shown in the manual using your favorite balancer. I place short pieces of masking tape on each wing and use a pen to mark the CG location (2 3/16 in. back). I was pleased to find that the airplane balanced at the recommended CG location and did not require relocation of the battery or addition of any weight.

• Check the lateral balance as described by the manual. Very many modelers forget this important step including myself. I needed to add right aileron trim for the first flights and surmised that there may be a warped wing. When I got home I realized that I had not checked the lateral balance so I did so immediately. I was not surprised to find that I needed to add ¼ oz. under the right wing tip. The wing was fine but the incorrect lateral balance caused the dropped wing in flight.

 

• There is a very comprehensive “Check List” printed in the manual and I applaud Great Planes for supplying this. Go through this list carefully to ensure that you didn’t miss anything. 

 

The end result of about 20 hours of assembly is simply one of the best looking airplanes at any field. Those tedious-to-apply decals help make this an outstanding looking airplane. Those folks at Cirrus sure know how to make a sharp looking airplane and the Great Planes version is just as eye catching.

Flight Results

I decide to take off with elevator and ailerons on high rates. I used high rate on rudder but programmed my rudder exponential to 75% to minimize the effect of the steerable nose wheel. I figured that I would need the maximum rudder throw for stall turns and spins since the rudder area is very small. The takeoff run was very short but straight and the model climbed out at a decent rate.

I reduced the power to obtain a reasonable cruise speed and needed to add left aileron trim and some down elevator trim. When I was satisfied with the trim settings I proceeded to do some rolls, loops, Immelman turns, and a split S. Lack of rudder authority provided initially poor stall turns but application of some power did help the airplane pivot and the stall turns improved.

It is important to check the stall characteristics and I was surprised to find out that the airplane really didn’t want to stall from a flat entry. Instead, it just held its heading while slowly sinking. I was able to achieve a good stall by bringing the nose up sharply and then cutting power. In either case the airplane exhibited very good slow flight characteristics which were a very pleasant surprise. This is an easy airplane to fly and makes a fine third airplane.

This airplane is not a slow flyer with high to medium power but it does slow down very nicely for landings. This does require a long low approach since the airplane will pick up speed when the nose is dropped. It is a clean, low drag design which matches its full size counterpart.

My first landing attempt turned into a fly-by but the next landings were very good once I gained confidence in its slow flight capability.

I think it should have some motor down thrust to minimize the climb on high power. Although I took off with both elevator and aileron rates in high, I did go to low aileron rate while airborne and found that rate to be very acceptable for an entire flight. The roll rate on low aileron was more preferable to me. I don’t like sensitive controls.

This reminds me that I should mention that I like to fly with 35% exponential on elevator and aileron. I usually do not go as high as 75% rudder exponential but I did on this airplane as explained earlier

Conclusion

This is a great looking airplane and is one of the best ARF’s I have seen or built. It flies great but requires some throttle management discipline. It is not for a novice pilot because of its speed in the air but more advance pilots will find that its aerobatics capability is outstanding. Although the wings are pluggable, its size will allow you to keep the wings attached since it will fit into most cars fully assembled.

Try this great model if you are looking for something small, great looking and a bit different from most of the planes at your flying field. I’m sure you will be happy with it. 

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