A High-Wing Sport Flyer with Classic Looks
The Sig Rascal has roots going back to the 1950’s with a small free flight model and they continued to make the design popular in many sizes over the years. They recently updated three sizes of the Rascal series with the most recent being the Rascal 72. I had the chance to fly many Rascals over the years and most recently used a Rascal 40 to give a Blue Angel pilot an introductory RC flight. When the opportunity came up to test out the new Rascal 72, I quickly jumped on it. I love the classic looks of the model and the transparent covering really makes the airframe stand out. The EG part of the name reflects Sig’s effort to make the updated kits easily setup for either electric or glow power. My closest field is a city-sponsored electric RC park, so I opted to install an electric power system. I’ve flown the original glow version at my club field and the flight characteristics were almost identical. However with the cost of lithium batteries continuing to come down, it’s not hard to have multiple packs ready for a full afternoon of flying on electric power. Perhaps my favorite feature is the two-piece wing design. This makes the plane easy to transport to the field and still have room in the van for my three boys. Anything that makes this hobby easier to share with my family is a plus in my book.
Sig has included an excellent manual with the Rascal 72. Each step is well documented with photographs to walk you through the build. Very few tools are needed and most modelers should be able to find them in your shop or flight box. A heat gun or covering iron might be needed to shrink any bubbles in the covering. I used Bob Smith Industries CA and Epoxy for the build plus blue thread locker on the motor mount and landing gear collets. I chose to use my Futaba 8FG, but any decent 4-6 channel radio will suffice. I used four Futaba S3004 servos for the control surfaces as I find them to be very reliable.
It took me about three short evenings to complete the model. When using an electric power system like I did, it helps to use a good mount like the ElectriFly medium brushless motor mount. It allows for exact spacing from the firewall to the spinner back plate. I also strongly recommend following the instructions to cut cooling holes in the cowl for the motor. I tried using just the lower holes for cooling, but felt the motor and ESC were not getting enough air so I went ahead and added the additional slots on the top. This is easily done with a Dremel tool and a cutoff wheel and then cleaned up with a sanding drum attachment.
The basic build can be completed in about 4-6 hours broken up over a couple evenings for things like letting the glue set. However, an extra day is needed if you want to get the decals perfect. Sig includes sticky back decals, but they recommend using soapy water or a glass cleaner solution to float the decals into place. This requires you to squeegee out the excess solution and then let the decals dry overnight to make sure they adhere to the covering. The only decal I had any trouble with was the door and that just takes some extra care to get in position without twisting it around. The decals help finish off the classic look of the airframe.
The only issue I had with the entire build was that one wheel pant did not want to line up with the predrilled holes in the landing gear. The wheel pants have blind nuts epoxied in place so I drilled out the aluminum gear mount just enough to allow the machine screw to line up with the blind nut. I checked with Sig on this and they got back to me right away. They are checking the manufacturing process to make sure the jigs are correct so that other kits won’t have this problem. It’s reassuring to have companies like Sig taking feedback and ensuring quality standards are met.
Need To Know
MANUFACTURER/DISTRIBUTOR: Sig Manufacturing, Inc.
TYPE: High-wing sport ARF
FOR: Intermediate sport pilots
MINIMUM FLYING AREA: RC club field
GEAR INCLUDED: Engine motor mount, fuel tank, wheels, spinner, and hardware
NEEDED TO COMPLETE: Requires a four channel radio with 4-5 standard servos and your choice of electric (500-800 watt) or glow (.40-.46 2-stroke) power systems
Having flown many of Sig’s airframes in the past, I was excited to try out the new Sig Rascal 72. The build was very easy with well fitting parts and an excellent step-by-step manual. The quality of the components included meant I was not spending extra money to replace subpar hardware. I chose an electric setup over glow as it allows me to fly it at more locations and events. In the air the Rascal 72 can be both relaxing and spirited, meaning it’s a great anyday plane to take to the field.
> The transparent covering scheme gives the Rascal great looks, but also makes it easy to see in the sky.
> The two-piece wing is strong, but also makes the airframe compact for transport and storage.
> Quality parts are used, from the laser-cut balsa and light plywood to the UltraCote covering.
> The kit is complete with all the hardware you need, including a glow engine mount. (Electric setups may require a motor mount or standoffs).
> The model includes a pre-installed battery hatch with twist fasteners, making electric setup a breeze.
> The quality of the build and materials used are excellent.
> The manual is very detailed with pictures for almost every step.
> The covering is excellent and the transparent sections show off the framework.
> Flight characteristics are excellent in both calm and windy conditions.
> I had to drill out the landing gear for one of the wheel pant mounts. Sig has already addressed this in manufacturing.
WINGSPAN: 72 in.
WING AREA: 720 sq. in.
FLYING WEIGHT: 5 lbs, 8 oz.
WING LOADING: 17.6 oz./sq. ft.
CUBE LOADING: 7.9
LENGTH: 51.75 in.
RADIO: Four channel required; Flown with a Futaba 8FGS transmitter, Futaba R617FS receiver, four S3004 servos, Exceed RC 3A BEC
MOTOR: ElectriFly RimFire .32
ESC: ElectriFly Silver Series 45A
PROPELLER/SPINNER: APC Thin E 13×6.5
BATTERY: Gens Ace 25c 4S 4000mAh
POWER CONSUMPTION: 44 amps / 690 watts
In The Air
When I went out to fly the Rascal 72 it was not the most ideal day, but it was clear and the winds were steady at about 7-10 mph. Assembly at the field is easy with just two servo connections for the ailerons and two nylon wing bolts. Sig included a battery hatch on the bottom of the nose area with two twist latches. This provides easy access for changing the battery. The Great Planes Silver Series has a safety feature on the ESC that it will not arm until you advance the throttle to full and back to idle. If you use a different ESC, I’d recommend adding an arming plug for safety so that the motor will not spin up until you’re ready. After checking the battery to ensure it had a full charge and balanced cells, I did a quick range check to verify that I’d have solid control. With everything checked, I ran it out on the runway to test the ground handling. The wide gear and long tail make it easy to control on the ground. The tail wheel was effective, but the tall vertical stabilizer will catch the wind and act as a weathervane if you’re not anticipating it. Some up elevator will help plant the tail wheel on the ground and give you good control.
I taxied to the end of the 650-foot runway and smoothly applied full power. The tail came up right away and the plane was airborne in less than 100 feet. At full power it had no problem climbing at a 45-degree angle. Once I was up at a safe altitude I powered back to about two-thirds throttle and checked the trim. It required just a few clicks of down trim for level flight. The Rascal handled the wind very well. I didn’t feel it being pushed around in the turns and the thin body and airfoil helped it cut through the upwind passes. On low rates the plane is as docile as most trainers. But flip on the high rates and it can be nimble and aerobatic. Stalls are mild with just a slight tip to the left side but recovery is easy by releasing the elevator and applying a little power. Like its bigger brother, the rolls are not axial, but more like barrel rolls. Adding in some rudder will help smooth them out. Loops are smooth and big with the RimFire .32 power system I used. The rudder may look small, but it is very effective. Stall turns were easy and even knife-edge passes were no problem for the Rascal 72. I enjoyed mixing up simple aerobatics with lazy passes.
With the headwind on this day landings were easy. I cut power back almost all the way and the plane slowed down, but still cut into the wind. I added a little power to smooth out the descent and it settled down on the runway with ease. I then went back up to try landing in the grass. The tall and wide gear handled the grass just fine. The takeoff required a little more power but once rolling it leapt back into the air. Landing was smooth and short with the added drag in the grass. The wheel pants did not seem to be an issue, as I did not feel like it wanted to nose over.
I taxied back to check the power system and make sure the cooling holes in the cowl had done their job. I unplugged the battery, which was hardly warm and then I checked the motor and ESC and both were barely warm. If you use a spinner like I did, be sure to cut the extra holes on the top of the cowl to get airflow around the motor and back to the ESC.
I went back out on a calm day to get a feel for take-off and landing without the wind. The plane flew basically the same, but landings required more approach area. The Rascal has a sleek design so without some headwind to slow down you’ll want a landing strip that is about 200 feet long for rollout. Coming in with a slip will help slow the plane down and a grass runway will cut that distance down as well. The only thing I would love to see added is a wing option to include flaps like its bigger brother, the Rascal 110.
Electrifly Rimfire .32 Power System
Electric power systems have evolved at a rapid rate over the past decade. It seems the cost to outfit larger planes becomes more affordable every year. A few years ago powering the Rascal 72 with an electric setup would have cost much more than the glow setup, but now they are more on par with each other, leaving the choice to preference rather than economics. The ElectriFly RimFire .32 is a great match for the Rascal 72. Matching it with the Medium Brushless Motor Mount and the ElectriFly Silver Series 45 amp ESC makes for an easy installation. The motor includes 3.5mm bullet connectors already soldered on and the ESC comes with matching connectors preinstalled along with a Deans T pin connector. This means no soldering for the builder assuming your batteries have a Deans-style connector installed as well. The motor mount allows for precise adjustment of the motor inside the cowl for that perfect fit with the spinner.
The RimFire .32 falls right in on the upper end of the recommended specs from Sig for the Rascal 72. At 800Kv and swinging an APC 13×6.5 Thin-E prop it produces 690 watts and 44 amps. This pulls the Rascal through the air with authority, but also allows for 10 minute flights or longer when paired with a 4000mAh 4S LiPo battery. This means the flight time will closely match the glow setup of a .40 engine.
I was very pleased with the performance of the RimFire .32 and Silver Series 45 amp ESC. The motor and ESC stayed cool even after a long flight on a hot summer day. I look forward to trying out more of the RimFire motors. The motors range from a micro 150 series all the way up to the 65cc motor for converting the giant scale planes. Check out the RimFire motors for your next project, as I’m sure you’ll be as pleased with it as I was.
The Last Word
The Sig Rascal 72 is a great aircraft for any day. It’s easy to see in the air and I love the classic lines. The sleek airframe will let you fly in more wind without being bounced around. I really like that it breaks down for easy storage and transport. The RimFire .32 gave it plenty of power and the 4000mAh battery gave plenty of flight time. Assembly was straightforward and could be completed within a few evenings. Once again Sig has set the bar high on quality in both the build and flight experience.
www.apcprop.com, (530) 661-0399
BOB SMITH INDUSTRIES
www.bsi-inc.com, (805) 466-1717
www.electrifly.com, (800) 637-7660
www.futaba-rc.com, (800) 637-7660
www.greatplanes.com, (800) 637-7660
www.sigmfg.com, (800) 247-5008
Words: Steve Mills