pettit
Dec 14, 2004, 02:00 AM
!Some History About the Famous Art Scholl and His Chipmunk
| spec2
| @913154
|> <b>Specifications:</b>
|> |< <b>Advertised |< <b>Measured
|> <b>Wingspan:</b> |< 81" |< 81"
|> <b>Wing Area:</b> |< 1000 in.<sup>2</sup>|< 1015 in.<sup>2</sup>|<
|> <b>Weight:</b> |< 13-14 lbs. |< 12 lbs. 10 oz.
|> <b>Length:</b> |< 62.5" |< 63.5"
|> <b>Wing Loading:</b> |< 29-32 oz/sq. ft. |< 28.66 oz/sq. ft.
|> <b>Prop shaft to ground:</b> |< n/a |< 12"
|> <hr>
|> <b>Requires:</b>
|> <b>Engine:</b> |< .91-1.08 2-stroke<br> .91-1.20 4-stroke
|> <b>Radio:</b> |< 5-ch Tx, 7 standard servos
|> <hr>
|> <b> Equipment Used:</b>
|> <b>Engine:</b> | OS FS-1.20<br>Surpass 4-stroke</a>
|> <b>Prop:</b> |< APC 17x6 wide
|> <b>Receiver:</b> |< Hitec Supreme
|> <b>Transmitter:</b> |< Hitec Eclipse
|> <b>Servos:</b> |< 6 HS-475HB<br>1 HS81
|> <b>Rx Pack:</b> |< 5-cell 1500mAh
|> <hr>
|> <b> Purchasing Info:</b>
|> <b>Street Price:</b> |< 379.99
|> <b>Manufacturer:</b> |< <a href=http://www.greatplanes.com.com>Great Planes</a>
|> <b>Available From:</b> |< <a href=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXGLK2&P=ML>Online from Tower Hobbies</a>
<i><small>The Art Scholl Chipmunk, constructor's number 116-154, was built at the de Havilland Toronto, Canada factory as part of an order by the Canadian Department of National Defense. In October of that year, it was purchased by the Winnipeg Flying Club and later certificated as airworthy. It was sold twice before being purchased by Sabre Industries of Winnipeg, in January 1967, for Robert "Skip" Volk of Aqua Craft Boat Company of Laverne, CA. Work to modify the aircraft for exhibition flying was started soon after it arrived from Canada. Modifications were likely done by Roy Sprague of Alcan Aluminum who had worked with Scholl in development of Super Chipmunks N13A and N13Y and Harold Krier's N 6311V. Sprague was assisted by Larry Riggs.
By late February 1970 with a total time of 3261 hours, the aircraft was further modified by Harry Dellicker of Del-Air at Steathmore, CA and classified as `Experimental Exhibition'. In early 1977, Art Scholl acquired N1114V for a new aerobatic routine and persuaded Bill Richards to part with the aircraft. Still painted in the early 1970's color scheme of blue stars and sunburst effect, Scholl fitted the plane with a red, white and blue wingtip and tail smoke system. The control stick received a three-inch extension for greater control during extreme aerobatic maneuvers and the plane completed the 1977 air show season in this form.
For 1978, the title "Super Chipmunk," Pennzoil logos and other marking were added to the aircraft's paint scheme. Avionics systems were upgraded for cross-country navigation and a Christen aerobatic fuel system and new front cockpit instruments were installed. Nineteen seventy eight was a typically busy air show season for Art and N1114V. Between March and July, they were in Tulsa, Memphis, Macon and Kissimmee. Some engine overheating problems are noted in the logs and additional cowling vents were fitted while in Florida. Art Scholl and his Super Chipmunk were often accompanied by his dog Aileron, sitting behind Scholl during the act, Aileron would walk out on the wing as they taxied in and jump onto Art's shoulder when he exited the cockpit. Art's routine was described in programs as "wild lomcevaks coupled with pyrotechnic spectaculars with a grand finale standing out on the wing waving to the crowd.
There were no bookings for the Super Chipmunk in 1985. This may have been due to Art's using his Pitts Special, N13AS, which was outfitted as a camera ship for film work. It was September 16, 1985 when Art and the Pitts were lost after the aircraft failed to recover from an inverted spin while filming for the movie "Top Gun." Neither pilot nor aircraft were recovered from the Pacific Ocean.
Art's widow, Judy Scholl, elected to donate his remaining aircraft to museums. Chipmunk N13Y went to the National Air and Space Museum in Washington, DC and N1114V to the EAA AirVenture Museum in Oshkosh, WI. Kevin Killingworth and Kevin Kammer, Art's chief mechanic, delivered it to Oshkosh on June 12, 1987 with 5183.5 total hours on the aircraft. The ferry flight from Rialto, CA to Oshkosh via Albuquerque, NM and La Crosse, WI took thirteen and a half hours. Their arrival was highlighted by the operation of the three-color smoke system for the last time.
Befitting the aerobatic and air show careers of both the aircraft and Art Scholl, N1114V is displayed inverted performing a ribbon cutting maneuver.</i> (Courtesy of the AirVenture Museum web site.)</small>
!!Full Scale Specifications:
|
|> <b>Wingspan (clipped):</b> |< 31'4"
|> <b>Length:</b> |< 25'5"
|> <b>Empty Weight:</b> |< 1430 lbs.
|> <b>Gross Weight:</b> |< 2056 lbs.
|> <b>Max Speed:</b> |< 168 mph
|> <b>Cruise Speed:</b> |< 150 mph
|> <b>Range:</b> |< 450 mi.
|> <b>Powerplant:</b> |< Lycoming GO-435, 260h
!Kit Contents and Highlights
@913155:Kit contents -- this is one complete kit! Note the included cockpit interior and pilot, and even a fuselage stand!
*Just a few of this kit's highlights:
*Painted and detailed fiberglass fuselage, cowl, wheel pants
*Wing panels and Tail surfaces covered with Top Flite MonoKote
*3-Piece Wing Can Remain 3-Piece for Transport
*Formed plastic canopy and cockpit interior with pilot
*Included fuselage stand!
*Includes nearly all required "incidentals", including:
*Adjustable plastic engine mount
*Fuel tank with hardware
*Formed wire main and tail landing gear with wheels
*All control linkages, horns, clevises, and rods
*All control surface hinges
*All required hardware
*<b>ITEMS NEEDED TO COMPLETE KIT</b>
*Engine with suitable prop and spinner
*Fuel tubing
*6 channel radio with 7 servos
*Suitable servo extensions and Y harnesses
*Appropriate adhesives (CA, epoxy)
*Basic hobby tools
!FIRST GLANCE
The Art Scholl Chipmunk stands out as one of the finest aerobatic airplanes that have ever flown. It stands to reason they Great Planes Model Manufacturing Co. Inc. has taken the time and put forth the effort to bring the R/C modeling community a giant scale representation of this beautiful aircraft. It is done in 1/5 scale (actually 21.5%) and is large enough to participate in IMAA events. I had printed off a copy of the instruction manual several weeks prior to actually receiving the kit and noticed that the rudder and tail wheel were both controlled by the same servo, using individual pull-pull cable linkages, and that the guide tubes for the rudder, tail wheel and elevator rods were already installed. Nice touches!
The Great Planes Super Chipmunk kit arrived at the shop in a very large shipping box, mainly due to the size of the fiberglass fuselage. There were two holes neatly punched through both the outer and inner shipping box by the shipping company, but luckily, upon further investigation, no damage was done to any of the contents. I took some time to unwrap all the various pieces and parts, checking them for any other damage and to weigh each one to get an idea about the total weight of the completed plane. Everything inside the box weighed 8.95 pounds, and since everything in there has to go in the air, it provided a good reference to total weight.
The 3-piece wing panels are made from balsa ribs, hardwood spars, and covered with Top Flite Monokote. The beautiful red, white and blue color scheme might look even sharper if black pin stripes were added at each color separation point, but it may not be scale. I’ll check on it though, and if I find the pin-striping would be scale, I'll add it.
I had familiarized myself with the assembly manual, ordered all the extra items I would need -- servos, a heavy prop hub and other odds and ends, and I was ready to start assembly. I used Pacer Brand Epoxy products and ZAP instant adhesives, and remembered that care must always be taken when using these or any type adhesives, especially CA's. Proper ventilation is mandatory during their use, and special precautions should also be taken when sanding or shaping fiberglass parts. So with those words of warning, I started putting together the new Great Planes Super Chipmunk.
!ASSEMBLY PROCESS
!!Wings
The first thing to do was to check the covering for wrinkles or bubbles, and shrink them down with a covering iron or a heat gun. I found a few, and all were gone with just a few passes of the heat. The ailerons and flaps were then installed using the CA type hinges and thin ZAP, making sure not to use too much.
I assembled the aileron and flap servos control rods using the supplied 4-40 rods and clevises. The solder clevises had to be silver soldered, not the type that needs high heat. I have been using plumbing solder that does not contain any lead with great results. It is harder than electrical solder, but can be applied with a common soldering gun. It was important that I get the parts clean, heat only the parts to be soldered, and wipe away any flux residue with some alcohol after the joint cooled. A thin wipe of common oil on the soldered joints also helped keep them from corroding.
@913156:Note the 3-piece wing, as well as the laminated balsa-and-aluminum joiner. The large black object sitting on the left panel is the thumb screw used to secure the wing panels in place.
@913157:The assembled wing can be permanently epoxied, or left as a 2- or 3-piece wing for easier transport.
The wing itself is actually made from three pieces, two outer panels and a center wood and fiberglass section that is removable from the fuselage. The kit included a wing joiner, a sandwich of an aluminum bar and two balsa pieces, that I epoxied together to make the dihedral joiner. This joiner was inserted through the center section, and the outer panels attached using 1/4-20 thumb screws, making them removable at any time, if desired. Many modelers don’t have the luxury of having a vehicle that can hold a one piece 81” wing, so the 2- or 3-piece transport option is a real plus.
The fit between the wing panels and the center section was absolutely perfect. The same held true for the fit between the center section and the fuselage..
!!Landing Gear
After the gear legs and pants were installed, a set of gear leg fairings were added and the main gear was complete. There were four extra plastic landing gear straps in the hardware bag that looked like they should go on the sides of the wheel pants to lock them to the gear legs. Without these straps, the wheel pants tended to rotate on the axle, making landings and take offs quite sketchy. The manual didn’t mention their installation, but there was a photo on the kit box that clearly showed the straps exactly where I thought they should go. I added them where the photo shows. Be sure to file or grind a flat on each axle where the collars are located to prevent an unwanted disposition of one of your wheels. Not that it has ever happened to me…
@913158:Note the impressive fuselage stand, cockpit interior and pilot that were included!
!!Fuselage
One of the neatest parts of the entire kit was the pre-assembled fuselage stand that replaced the wing center section. It allowed the builder to work on the model without having it roll off the table.
I really should have installed the elevator and rudder horns before mounting the tail, rather than add them when specified in the manual. It would have made their installation a lot easier.
The engine and mount were installed using the printed template in the manual. The mount fit the fuselage and the engine fit the mount, so what more could I ask for? The manual suggested the use of an OS header adapter to keep the muffler from sticking out the side of the cowl. I had my local hobby dealer order me one, and I was shocked at the price. They wanted almost $30.00 for a little piece of bent tubing with threads on each end! But, on the other hand, the muffler installation was neat and tidy inside the cowl. A short section of high temperature exhaust tubing was added to keep the goop out of the fuselage tunnel.
@913159:The throttle servo was firewall-mounted to aid in balancing the model.
Rather than place the throttle servo inside the fuselage, I added a mini throttle servo directly on the firewall, well ahead of the balance point, to keep the need for extra nose weight to a minimum.
The painted fiberglass cowl was mounted using a set of balsa rings that slip over the drive washer on the OS 120 four cycle engine. this spacer positioned the prop shaft centered in the cowl opening. Quite a bit of material had to be removed from the side of the cowl to clear the cylinder head, but the good news is this increased the cooling air over the engine. The cowl then screwed to the fuselage and other than making a clearance hole for the needle valve, that part of the assembly is complete. As a side note, the rear lip of the cowl came factory reinforced with a strip of carbon fiber, exactly at the spot that the mounting holes were to be drilled. Imagine that!
@913160:The rudder servo installation included 2 sets of pull-pull cables. I chose to add springs on the tail wheel cables to reduce the load on the servo.
@913161:The rudder, elevator, antenna and tailwheel pushrod tubes were all preinstalled by the manufacturer.
Heading inside the fuselage, the elevator, rudder and throttle servos were mounted on the removable servo mounting plate, and the control linkages assembled and installed. The rudder and tail wheel were controlled by the same servo horn, meaning that any side load on the tail wheel during ground operation could place unnecessary force on the servo. Rather than connect the tail wheel pull-pull cables solidly to the servo arm, I chose to add a pair of small coil springs that allowed full movement but gave a bit if the tail wheel turned due to ground handling.
Preinstalled was even a set of four tubes that guide the pull-pull cables to the rear of the fuselage. Another set of tubes were for the elevator push rods, and they connected together at the servo using a pair of wheel collars. I chose to align them, install the collars and then wrap them with copper wire and apply a bit of solder for extra strength.
Next I installed the cockpit deck, instrument panel, pilot figure and canopy. That pilot looked a bit like the guy that used to fly my Great Planes Super Stearman! The large sheet of self-stick graphics looked intimidating, but once they were cut from the sheet, they were easy to apply using a few spritzes of household window cleaner on the fiberglass fuselage. I kept a photo from the side of the kit box handy to show where the graphics were applied, since the manual didn’t include a very clear photo of the competed fuselage.
@913162: Here's the 5 cell 1500 maH battery rubber banded under the engine. Notice the safety tie wrap snugly holding it in place.
With everything complete, I checked the balance of the Chipmunk using the dimensions stated in the manual. I also remembered the manual stated that Great Planes had to add 20 ounces to the nose of their Chipmunk to get it to balance. I had the same concern with the Great Planes Super Stearman, and solved it by placing a rather heavy five cell battery pack directly on the engine mount. I did the same on the Chipmunk, along with adding a DuBro heavy prop hub to the crankshaft. The results? The Chipmunk balanced perfectly without any useless weight on the nose. But the really great part of this experiment was that the total weight of the Chipmunk was 12.5 pounds, a full half a pound less than the minimum advertised weight! When was the last time that ever happened?
(Modeling scale aircraft, especially vintage ones that utilized huge, heavy engines, can be challenging. Great Planes obviously made the decision in both these projects to keep scale proportions to the aircraft, keeping the model looking realistic, rather than 'cheat' and lengthen the nose to get the model to balance without the need of any nose weight. I definitely prefer this "stick to scale" approach!)
When I went to adjust the control throws, I read in the manual that the elevator throws were “1 inch and 5/8 inch Left and Right”. Hopefully this was just a typographical error, or otherwise I had my stabilizer 90 degrees out of phase. I set up my flaps for about half deployment when the “landing” switch on my Hitec Eclipse transmitter was activated. Full flaps were also available on the flap knob. All the other control throws looked suitable for a model of this type and size.
!!Break-In
@913163: The Chipmunk ready for it's first engine run (minus cowl)!
@913164: Rear quarter view of the Chipmunk sitting on the workbench, ready to go outside for engine testing.
It was time to run and adjust the engine out in the backyard! After a tank of 15% glow fuel was pumped into the tank, a few priming turns and a slight application of my Sullivan starter got the OS 120 running very nicely. It took a little adjustment on the low speed needle, but it was purring like a kitten. There’s not much ground clearance, and a 16” prop had to replace the 18” APC. I let the engine run through a full tank of fuel at a rich half-throttle setting, and it was time to wait for a nice day for the first flights.
!FLYING
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A very nice December Saturday turned out to be perfect for the test flights of the Great Planes Super Chipmunk. The big OS 120 Surpass sprang to life with a few flips of the prop. I made a power-on radio range check, finding that control was still solid at about 100 feet, and it was time to take the Chipmunk to the clouds.
I purposely set the control throws to the low rate position to keep from over-controlling on the ground. At the far end of the runway, power was slowly added, the Chipmunk began rolling at a brisk pace and at the middle of the grass strip, it took to the air as gently as a feather. It took just a few digital clicks of aileron and elevator trim to maintain hands-off level flight, as most new models do. I made a few high and low speed passes and then used full throttle to get to a safe altitude. Power was reduced to idle, the elevator slowly pulled back all the way and the Chipmunk just hung in the air, never once dropping it’s nose or either wing tip. It looked as if the balance point I had chosen was a good one.
Back on the power, I did a few loops and a roll, finding that low rate aileron was not quite enough to perform a nice axial roll. I could do several consecutive loops, either large or small, with no tendency to drop out at the top. Even an outside loop, starting at the top, was easy to do. I again added full power, climbed to another safe level, cut the power, added full elevator and hit full left rudder. The Chipmunk started a beautiful spin, and continued for several turns. The instant the controls were centered, the Chipmunk stopped spinning and flew out of the maneuver. At no time during the entire first flight was full power ever needed, except for totally vertical maneuvers. The OS 120 was a good choice of engine for this particular model.
It was time for that dreaded first landing, so power was reduced on the downwind leg, partial flaps were added, followed by an even lower power setting on the base leg. On final approach, power was cut to idle, full flaps were added and the nose pointed down slightly. The Chipmunk came across the threshold at a brisk pace, but a nice wheel landing was made with just a bit of runway left to spare. I had to turn down the idle speed a bit before the next flight.
After refueling and checking for loose or missing parts, the Chipmunk was flown again and again, each time getting a little more “enthusiastic” with flight maneuvers. More spins and stall turns were done, and even some absolutely stable inverted flight, using just a small amount of down elevator to keep it level. I thought that one time I was getting a little too enthusiastic after a mistake in a knife edge pass turned into an emergency half loop, made at a rather low altitude. There was plenty of airspace left to complete the loop, but I was concerned that the very fast and tight loop may have weakened the wing. It turned out that the only thing weakened by that maneuver was my knees!
I flew the Great Planes Super Chipmunk the rest of the morning, using almost ¾ gallon of fuel in the process. I found nothing the plane could not do, given the type and size of the model. I was completely satisfied with it’s performance, and so were the others at the field that day. I went home with a good feeling about the Chipmunk and that was for a very good reason. It simply is a very nice flying model, period.
!Flight Photo/Video Gallery:
@913154
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+913180:A brief flight video, low resolution for dial up users.
+913181:Same video, higher resolution.
!CONCLUSION
*UP’S:
*Very complete kit,
*Great looking fiberglass fuselage and cowl,
*Three piece wing option,
*Assembly stand is an excellent addition
*Excellent flyer
*VERY photogenic!
*DOWN’S:
*Several small details incorrectly stated in manual,
*formers made ridges in fiberglass fuselage
It’s always hard to come up with some sort of a conclusion to any model review, especially when most of it has already been written in the assembly and flight portion of the review. But when a plane like the Great Planes Super Chipmunk comes along, there’s a lot to be said for its performance. It assembles very easily and quickly, with top notch hardware and accessories right there in the kit box. Everything fits just fine, maybe a little sanding was needed on the wing joiner brace, but that’s about all. There may have been a few typographical errors and one small item left out in the manual, but that’s just incidental. The Chipmunk kit was assembled in just a few hours, and the results were simply stunning.
I have heard than many modelers were considering the use of a gas/ignition engine on the Chipmunk. I suppose that one could be installed with little difficulty, but the sound of the OS four cycle engine just sounds so nice. The model came out underweight and balanced wonderfully. I’d have to give it a lot of thought to swap it for something like a gas engine.
My conclusion? I feel that Great Planes has a real winner here with the Super Chipmunk, and I feel quite certain that we’ll be seeing quite a few of them at the local flying fields in the coming months.
| spec2
| @913154
|> <b>Specifications:</b>
|> |< <b>Advertised |< <b>Measured
|> <b>Wingspan:</b> |< 81" |< 81"
|> <b>Wing Area:</b> |< 1000 in.<sup>2</sup>|< 1015 in.<sup>2</sup>|<
|> <b>Weight:</b> |< 13-14 lbs. |< 12 lbs. 10 oz.
|> <b>Length:</b> |< 62.5" |< 63.5"
|> <b>Wing Loading:</b> |< 29-32 oz/sq. ft. |< 28.66 oz/sq. ft.
|> <b>Prop shaft to ground:</b> |< n/a |< 12"
|> <hr>
|> <b>Requires:</b>
|> <b>Engine:</b> |< .91-1.08 2-stroke<br> .91-1.20 4-stroke
|> <b>Radio:</b> |< 5-ch Tx, 7 standard servos
|> <hr>
|> <b> Equipment Used:</b>
|> <b>Engine:</b> | OS FS-1.20<br>Surpass 4-stroke</a>
|> <b>Prop:</b> |< APC 17x6 wide
|> <b>Receiver:</b> |< Hitec Supreme
|> <b>Transmitter:</b> |< Hitec Eclipse
|> <b>Servos:</b> |< 6 HS-475HB<br>1 HS81
|> <b>Rx Pack:</b> |< 5-cell 1500mAh
|> <hr>
|> <b> Purchasing Info:</b>
|> <b>Street Price:</b> |< 379.99
|> <b>Manufacturer:</b> |< <a href=http://www.greatplanes.com.com>Great Planes</a>
|> <b>Available From:</b> |< <a href=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXGLK2&P=ML>Online from Tower Hobbies</a>
<i><small>The Art Scholl Chipmunk, constructor's number 116-154, was built at the de Havilland Toronto, Canada factory as part of an order by the Canadian Department of National Defense. In October of that year, it was purchased by the Winnipeg Flying Club and later certificated as airworthy. It was sold twice before being purchased by Sabre Industries of Winnipeg, in January 1967, for Robert "Skip" Volk of Aqua Craft Boat Company of Laverne, CA. Work to modify the aircraft for exhibition flying was started soon after it arrived from Canada. Modifications were likely done by Roy Sprague of Alcan Aluminum who had worked with Scholl in development of Super Chipmunks N13A and N13Y and Harold Krier's N 6311V. Sprague was assisted by Larry Riggs.
By late February 1970 with a total time of 3261 hours, the aircraft was further modified by Harry Dellicker of Del-Air at Steathmore, CA and classified as `Experimental Exhibition'. In early 1977, Art Scholl acquired N1114V for a new aerobatic routine and persuaded Bill Richards to part with the aircraft. Still painted in the early 1970's color scheme of blue stars and sunburst effect, Scholl fitted the plane with a red, white and blue wingtip and tail smoke system. The control stick received a three-inch extension for greater control during extreme aerobatic maneuvers and the plane completed the 1977 air show season in this form.
For 1978, the title "Super Chipmunk," Pennzoil logos and other marking were added to the aircraft's paint scheme. Avionics systems were upgraded for cross-country navigation and a Christen aerobatic fuel system and new front cockpit instruments were installed. Nineteen seventy eight was a typically busy air show season for Art and N1114V. Between March and July, they were in Tulsa, Memphis, Macon and Kissimmee. Some engine overheating problems are noted in the logs and additional cowling vents were fitted while in Florida. Art Scholl and his Super Chipmunk were often accompanied by his dog Aileron, sitting behind Scholl during the act, Aileron would walk out on the wing as they taxied in and jump onto Art's shoulder when he exited the cockpit. Art's routine was described in programs as "wild lomcevaks coupled with pyrotechnic spectaculars with a grand finale standing out on the wing waving to the crowd.
There were no bookings for the Super Chipmunk in 1985. This may have been due to Art's using his Pitts Special, N13AS, which was outfitted as a camera ship for film work. It was September 16, 1985 when Art and the Pitts were lost after the aircraft failed to recover from an inverted spin while filming for the movie "Top Gun." Neither pilot nor aircraft were recovered from the Pacific Ocean.
Art's widow, Judy Scholl, elected to donate his remaining aircraft to museums. Chipmunk N13Y went to the National Air and Space Museum in Washington, DC and N1114V to the EAA AirVenture Museum in Oshkosh, WI. Kevin Killingworth and Kevin Kammer, Art's chief mechanic, delivered it to Oshkosh on June 12, 1987 with 5183.5 total hours on the aircraft. The ferry flight from Rialto, CA to Oshkosh via Albuquerque, NM and La Crosse, WI took thirteen and a half hours. Their arrival was highlighted by the operation of the three-color smoke system for the last time.
Befitting the aerobatic and air show careers of both the aircraft and Art Scholl, N1114V is displayed inverted performing a ribbon cutting maneuver.</i> (Courtesy of the AirVenture Museum web site.)</small>
!!Full Scale Specifications:
|
|> <b>Wingspan (clipped):</b> |< 31'4"
|> <b>Length:</b> |< 25'5"
|> <b>Empty Weight:</b> |< 1430 lbs.
|> <b>Gross Weight:</b> |< 2056 lbs.
|> <b>Max Speed:</b> |< 168 mph
|> <b>Cruise Speed:</b> |< 150 mph
|> <b>Range:</b> |< 450 mi.
|> <b>Powerplant:</b> |< Lycoming GO-435, 260h
!Kit Contents and Highlights
@913155:Kit contents -- this is one complete kit! Note the included cockpit interior and pilot, and even a fuselage stand!
*Just a few of this kit's highlights:
*Painted and detailed fiberglass fuselage, cowl, wheel pants
*Wing panels and Tail surfaces covered with Top Flite MonoKote
*3-Piece Wing Can Remain 3-Piece for Transport
*Formed plastic canopy and cockpit interior with pilot
*Included fuselage stand!
*Includes nearly all required "incidentals", including:
*Adjustable plastic engine mount
*Fuel tank with hardware
*Formed wire main and tail landing gear with wheels
*All control linkages, horns, clevises, and rods
*All control surface hinges
*All required hardware
*<b>ITEMS NEEDED TO COMPLETE KIT</b>
*Engine with suitable prop and spinner
*Fuel tubing
*6 channel radio with 7 servos
*Suitable servo extensions and Y harnesses
*Appropriate adhesives (CA, epoxy)
*Basic hobby tools
!FIRST GLANCE
The Art Scholl Chipmunk stands out as one of the finest aerobatic airplanes that have ever flown. It stands to reason they Great Planes Model Manufacturing Co. Inc. has taken the time and put forth the effort to bring the R/C modeling community a giant scale representation of this beautiful aircraft. It is done in 1/5 scale (actually 21.5%) and is large enough to participate in IMAA events. I had printed off a copy of the instruction manual several weeks prior to actually receiving the kit and noticed that the rudder and tail wheel were both controlled by the same servo, using individual pull-pull cable linkages, and that the guide tubes for the rudder, tail wheel and elevator rods were already installed. Nice touches!
The Great Planes Super Chipmunk kit arrived at the shop in a very large shipping box, mainly due to the size of the fiberglass fuselage. There were two holes neatly punched through both the outer and inner shipping box by the shipping company, but luckily, upon further investigation, no damage was done to any of the contents. I took some time to unwrap all the various pieces and parts, checking them for any other damage and to weigh each one to get an idea about the total weight of the completed plane. Everything inside the box weighed 8.95 pounds, and since everything in there has to go in the air, it provided a good reference to total weight.
The 3-piece wing panels are made from balsa ribs, hardwood spars, and covered with Top Flite Monokote. The beautiful red, white and blue color scheme might look even sharper if black pin stripes were added at each color separation point, but it may not be scale. I’ll check on it though, and if I find the pin-striping would be scale, I'll add it.
I had familiarized myself with the assembly manual, ordered all the extra items I would need -- servos, a heavy prop hub and other odds and ends, and I was ready to start assembly. I used Pacer Brand Epoxy products and ZAP instant adhesives, and remembered that care must always be taken when using these or any type adhesives, especially CA's. Proper ventilation is mandatory during their use, and special precautions should also be taken when sanding or shaping fiberglass parts. So with those words of warning, I started putting together the new Great Planes Super Chipmunk.
!ASSEMBLY PROCESS
!!Wings
The first thing to do was to check the covering for wrinkles or bubbles, and shrink them down with a covering iron or a heat gun. I found a few, and all were gone with just a few passes of the heat. The ailerons and flaps were then installed using the CA type hinges and thin ZAP, making sure not to use too much.
I assembled the aileron and flap servos control rods using the supplied 4-40 rods and clevises. The solder clevises had to be silver soldered, not the type that needs high heat. I have been using plumbing solder that does not contain any lead with great results. It is harder than electrical solder, but can be applied with a common soldering gun. It was important that I get the parts clean, heat only the parts to be soldered, and wipe away any flux residue with some alcohol after the joint cooled. A thin wipe of common oil on the soldered joints also helped keep them from corroding.
@913156:Note the 3-piece wing, as well as the laminated balsa-and-aluminum joiner. The large black object sitting on the left panel is the thumb screw used to secure the wing panels in place.
@913157:The assembled wing can be permanently epoxied, or left as a 2- or 3-piece wing for easier transport.
The wing itself is actually made from three pieces, two outer panels and a center wood and fiberglass section that is removable from the fuselage. The kit included a wing joiner, a sandwich of an aluminum bar and two balsa pieces, that I epoxied together to make the dihedral joiner. This joiner was inserted through the center section, and the outer panels attached using 1/4-20 thumb screws, making them removable at any time, if desired. Many modelers don’t have the luxury of having a vehicle that can hold a one piece 81” wing, so the 2- or 3-piece transport option is a real plus.
The fit between the wing panels and the center section was absolutely perfect. The same held true for the fit between the center section and the fuselage..
!!Landing Gear
After the gear legs and pants were installed, a set of gear leg fairings were added and the main gear was complete. There were four extra plastic landing gear straps in the hardware bag that looked like they should go on the sides of the wheel pants to lock them to the gear legs. Without these straps, the wheel pants tended to rotate on the axle, making landings and take offs quite sketchy. The manual didn’t mention their installation, but there was a photo on the kit box that clearly showed the straps exactly where I thought they should go. I added them where the photo shows. Be sure to file or grind a flat on each axle where the collars are located to prevent an unwanted disposition of one of your wheels. Not that it has ever happened to me…
@913158:Note the impressive fuselage stand, cockpit interior and pilot that were included!
!!Fuselage
One of the neatest parts of the entire kit was the pre-assembled fuselage stand that replaced the wing center section. It allowed the builder to work on the model without having it roll off the table.
I really should have installed the elevator and rudder horns before mounting the tail, rather than add them when specified in the manual. It would have made their installation a lot easier.
The engine and mount were installed using the printed template in the manual. The mount fit the fuselage and the engine fit the mount, so what more could I ask for? The manual suggested the use of an OS header adapter to keep the muffler from sticking out the side of the cowl. I had my local hobby dealer order me one, and I was shocked at the price. They wanted almost $30.00 for a little piece of bent tubing with threads on each end! But, on the other hand, the muffler installation was neat and tidy inside the cowl. A short section of high temperature exhaust tubing was added to keep the goop out of the fuselage tunnel.
@913159:The throttle servo was firewall-mounted to aid in balancing the model.
Rather than place the throttle servo inside the fuselage, I added a mini throttle servo directly on the firewall, well ahead of the balance point, to keep the need for extra nose weight to a minimum.
The painted fiberglass cowl was mounted using a set of balsa rings that slip over the drive washer on the OS 120 four cycle engine. this spacer positioned the prop shaft centered in the cowl opening. Quite a bit of material had to be removed from the side of the cowl to clear the cylinder head, but the good news is this increased the cooling air over the engine. The cowl then screwed to the fuselage and other than making a clearance hole for the needle valve, that part of the assembly is complete. As a side note, the rear lip of the cowl came factory reinforced with a strip of carbon fiber, exactly at the spot that the mounting holes were to be drilled. Imagine that!
@913160:The rudder servo installation included 2 sets of pull-pull cables. I chose to add springs on the tail wheel cables to reduce the load on the servo.
@913161:The rudder, elevator, antenna and tailwheel pushrod tubes were all preinstalled by the manufacturer.
Heading inside the fuselage, the elevator, rudder and throttle servos were mounted on the removable servo mounting plate, and the control linkages assembled and installed. The rudder and tail wheel were controlled by the same servo horn, meaning that any side load on the tail wheel during ground operation could place unnecessary force on the servo. Rather than connect the tail wheel pull-pull cables solidly to the servo arm, I chose to add a pair of small coil springs that allowed full movement but gave a bit if the tail wheel turned due to ground handling.
Preinstalled was even a set of four tubes that guide the pull-pull cables to the rear of the fuselage. Another set of tubes were for the elevator push rods, and they connected together at the servo using a pair of wheel collars. I chose to align them, install the collars and then wrap them with copper wire and apply a bit of solder for extra strength.
Next I installed the cockpit deck, instrument panel, pilot figure and canopy. That pilot looked a bit like the guy that used to fly my Great Planes Super Stearman! The large sheet of self-stick graphics looked intimidating, but once they were cut from the sheet, they were easy to apply using a few spritzes of household window cleaner on the fiberglass fuselage. I kept a photo from the side of the kit box handy to show where the graphics were applied, since the manual didn’t include a very clear photo of the competed fuselage.
@913162: Here's the 5 cell 1500 maH battery rubber banded under the engine. Notice the safety tie wrap snugly holding it in place.
With everything complete, I checked the balance of the Chipmunk using the dimensions stated in the manual. I also remembered the manual stated that Great Planes had to add 20 ounces to the nose of their Chipmunk to get it to balance. I had the same concern with the Great Planes Super Stearman, and solved it by placing a rather heavy five cell battery pack directly on the engine mount. I did the same on the Chipmunk, along with adding a DuBro heavy prop hub to the crankshaft. The results? The Chipmunk balanced perfectly without any useless weight on the nose. But the really great part of this experiment was that the total weight of the Chipmunk was 12.5 pounds, a full half a pound less than the minimum advertised weight! When was the last time that ever happened?
(Modeling scale aircraft, especially vintage ones that utilized huge, heavy engines, can be challenging. Great Planes obviously made the decision in both these projects to keep scale proportions to the aircraft, keeping the model looking realistic, rather than 'cheat' and lengthen the nose to get the model to balance without the need of any nose weight. I definitely prefer this "stick to scale" approach!)
When I went to adjust the control throws, I read in the manual that the elevator throws were “1 inch and 5/8 inch Left and Right”. Hopefully this was just a typographical error, or otherwise I had my stabilizer 90 degrees out of phase. I set up my flaps for about half deployment when the “landing” switch on my Hitec Eclipse transmitter was activated. Full flaps were also available on the flap knob. All the other control throws looked suitable for a model of this type and size.
!!Break-In
@913163: The Chipmunk ready for it's first engine run (minus cowl)!
@913164: Rear quarter view of the Chipmunk sitting on the workbench, ready to go outside for engine testing.
It was time to run and adjust the engine out in the backyard! After a tank of 15% glow fuel was pumped into the tank, a few priming turns and a slight application of my Sullivan starter got the OS 120 running very nicely. It took a little adjustment on the low speed needle, but it was purring like a kitten. There’s not much ground clearance, and a 16” prop had to replace the 18” APC. I let the engine run through a full tank of fuel at a rich half-throttle setting, and it was time to wait for a nice day for the first flights.
!FLYING
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A very nice December Saturday turned out to be perfect for the test flights of the Great Planes Super Chipmunk. The big OS 120 Surpass sprang to life with a few flips of the prop. I made a power-on radio range check, finding that control was still solid at about 100 feet, and it was time to take the Chipmunk to the clouds.
I purposely set the control throws to the low rate position to keep from over-controlling on the ground. At the far end of the runway, power was slowly added, the Chipmunk began rolling at a brisk pace and at the middle of the grass strip, it took to the air as gently as a feather. It took just a few digital clicks of aileron and elevator trim to maintain hands-off level flight, as most new models do. I made a few high and low speed passes and then used full throttle to get to a safe altitude. Power was reduced to idle, the elevator slowly pulled back all the way and the Chipmunk just hung in the air, never once dropping it’s nose or either wing tip. It looked as if the balance point I had chosen was a good one.
Back on the power, I did a few loops and a roll, finding that low rate aileron was not quite enough to perform a nice axial roll. I could do several consecutive loops, either large or small, with no tendency to drop out at the top. Even an outside loop, starting at the top, was easy to do. I again added full power, climbed to another safe level, cut the power, added full elevator and hit full left rudder. The Chipmunk started a beautiful spin, and continued for several turns. The instant the controls were centered, the Chipmunk stopped spinning and flew out of the maneuver. At no time during the entire first flight was full power ever needed, except for totally vertical maneuvers. The OS 120 was a good choice of engine for this particular model.
It was time for that dreaded first landing, so power was reduced on the downwind leg, partial flaps were added, followed by an even lower power setting on the base leg. On final approach, power was cut to idle, full flaps were added and the nose pointed down slightly. The Chipmunk came across the threshold at a brisk pace, but a nice wheel landing was made with just a bit of runway left to spare. I had to turn down the idle speed a bit before the next flight.
After refueling and checking for loose or missing parts, the Chipmunk was flown again and again, each time getting a little more “enthusiastic” with flight maneuvers. More spins and stall turns were done, and even some absolutely stable inverted flight, using just a small amount of down elevator to keep it level. I thought that one time I was getting a little too enthusiastic after a mistake in a knife edge pass turned into an emergency half loop, made at a rather low altitude. There was plenty of airspace left to complete the loop, but I was concerned that the very fast and tight loop may have weakened the wing. It turned out that the only thing weakened by that maneuver was my knees!
I flew the Great Planes Super Chipmunk the rest of the morning, using almost ¾ gallon of fuel in the process. I found nothing the plane could not do, given the type and size of the model. I was completely satisfied with it’s performance, and so were the others at the field that day. I went home with a good feeling about the Chipmunk and that was for a very good reason. It simply is a very nice flying model, period.
!Flight Photo/Video Gallery:
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+913180:A brief flight video, low resolution for dial up users.
+913181:Same video, higher resolution.
!CONCLUSION
*UP’S:
*Very complete kit,
*Great looking fiberglass fuselage and cowl,
*Three piece wing option,
*Assembly stand is an excellent addition
*Excellent flyer
*VERY photogenic!
*DOWN’S:
*Several small details incorrectly stated in manual,
*formers made ridges in fiberglass fuselage
It’s always hard to come up with some sort of a conclusion to any model review, especially when most of it has already been written in the assembly and flight portion of the review. But when a plane like the Great Planes Super Chipmunk comes along, there’s a lot to be said for its performance. It assembles very easily and quickly, with top notch hardware and accessories right there in the kit box. Everything fits just fine, maybe a little sanding was needed on the wing joiner brace, but that’s about all. There may have been a few typographical errors and one small item left out in the manual, but that’s just incidental. The Chipmunk kit was assembled in just a few hours, and the results were simply stunning.
I have heard than many modelers were considering the use of a gas/ignition engine on the Chipmunk. I suppose that one could be installed with little difficulty, but the sound of the OS four cycle engine just sounds so nice. The model came out underweight and balanced wonderfully. I’d have to give it a lot of thought to swap it for something like a gas engine.
My conclusion? I feel that Great Planes has a real winner here with the Super Chipmunk, and I feel quite certain that we’ll be seeing quite a few of them at the local flying fields in the coming months.