March/April 2024 51 IN THE AIR After conducting a range and function testit was time to launch the Tempest forthe firsttime. With no ballast installed I launched into a head wind of about15mph. I used increased camber (ailerons and flaps down 1.5mm)to give me as much lift as possible and this allowed me to gain height of around 40 feet, Ithen headed along the ridge of the slope gaining height as I went. GENERAL FLIGHT PERFORMANCE Stability and tracking: The Tempest is an extremely fast model and when Iturned forthe downwind leg, I could see it picking up speed. It came past at an incredible pace and the whistling sound coming from the airframe really added to the enjoyment ofthe flight. Allthe controls seemed well balanced, the aileron control was perfect, and the rollrate was impressive. Glide and stall performance: The rudder had good authority, and this made it easy to conduct stallturns both into the wind and down wind. With the speed ofthe Tempestthe energy it stored after a dive allowed itto climb vertically. A large reversal would build even more speed and this allowed lots of vertical maneuvers and lots of speed. It’s fantastic to have lots of speed howeverthere comes a time when you have to slow down to land. I’m pleased to say the crow brakes work very well and helped to scrub off speed before landing. Some down-elevator will need to be programmed into the crow brakes to reduce the ballooning effect, butthis is standard mixing forthis style of model. The Tempest slowed down nicely and did not show any signs oftip-stalling. As I came down with a nice sink rate, I eased off the flaps just before landing to protectthe flaps from damage as they would hitthe ground when fully down. PILOT DEBRIEFING When I flew the Tempestin lightlift conditions, I selected thermal mode thatincreased the camber ofthe wing. This allowed me to fly without problems and I could still gain height should I feel I was struggling for hight orif I was in turbulent air. The Tempest wing is semi symmetrical, and this does seem to produce an incredible amount of lift. BOTTOM LINE The TJIRC Tempestis a highperformance gliderthatis supplied with a high level of completion and is relatively simple to assemble and get flightready. The high-quality fiberglass moldings are well made, and the fit ofthe parts is first class. The flight performance is excellentin a wide range of wind speeds and conditions with no unpleasant mannerisms. The Tempestreally does represent fantastic value for money atits price point. 1. The top ofthe rudder has a pre-cut opening forthe elevator pushrod. This needed a small amount of adjustmentto reduce binding atfulltravel. 2. I used tape to mark outthe elevator horn location. When ready, it needs to be epoxied into position. 3. The rudder control horn and linkage have an aerodynamic molding added to the fuselage. Above the linkage you can see the rudder gap seal in white. 1 3 2
52 ModelAirplaneNews.com CONSTRUCTION TEXT & PHOTOS BY MARK SIRIANNI SUKHOI SU-26 This low-budget, high-fun aerobat is a fast build FREE PLAN!
March/April 2024 53 I n 1989 I had the opportunity to see the firsttwo Russian Sukhois fly atthe EAA AirVenture airshow in Oshkosh, Wisconsin. That day I fell in love with this plane. I have designed two RC models ofthe Sukhoi,the first was published in Model Aviation in 1994 and the second was published in Model Airplane News in July 1996. I am now flying electric so it seems naturalthat my next design would be an e-powered Su-26. I have been flying models in the 3-pound range using my trusty Hacker A30 10L V4 motor, so thatis the motor thatI designed the plane around. The finished weight ofthis model came in at 3 lb., 8 oz.,ready to fly. Itis built mostly of1/4- and 1/8-in. Depron foam with some internal plywood and balsa structures. I use Clear Gorilla glue, which is very strong and does notfoam. It sticks to foam, balsa, and plywood. Itis not a fast drying glue, so things need to be pinned in place for a bitto dry. The Sukhoi Su-26 is a fairly quick and easy to build, so let’s get started. BUILDING THE WING AND TAIL Cut all14 ofthe ribs from 1/4-inch foam. This is a two-piece, plug-in wing design, so a bit of care needs to be taken when cutting the tube hole in each of the three centerribs. Both wing halves are built overthe left wing drawing on the plan. Since I am using a fully symmetrical airfoil, you can build both the right and left wing overthe plan, and just flip it overforthe right wing. The only difference in the halves is to make sure you installthe aileron servo mount on the bottom of each half. Don’t build
54 ModelAirplaneNews.com CONSTRUCTION: SUKHOI SU-26 two left wings! Add the 1/8 ply tube brace to the three inside ribs as noted on the plan. Cap the center wing rib with 3/32 balsa to add some stiffness to this rib. Pin the 1/4 x 5/8-inch balsa jig to the plan,1inch from the trailing edge ofthe wing. Cut and pin the bottom 1/4-in.-sq. balsa bottom sparin place. Pin each ofthe seven wing ribs overthe plan and pin to the rearjig. Make sure thatthe three centerribs are vertical and thatthe tube braces are positioned properly. Glue the top 1/4-in.-sq. spar in place. You can test-fitthe wing tube through the three centerribs, but do not glue itin place yet. Add the 1/8 x 3/8 leading and trailing edge pieces. Add the 5/16-in.-sq. balsa trailing edge. Let everything dry. Keep it pinned to the building board and jig, add the 1/16 x 1 inch trailing edge sheeting, and the 1/16 x 4 leading edge sheeting. Don’t sheet the center yet. Add the cap strips where indicated. When dry,remove from the board and repeatthe steps forthe right wing panel. Add the bottom 1/6 leading- and trailing-edge sheeting, but don’t sheet the center atthis time. Draw a line down the middle ofthe inside rib exactly down the center. Drillthe holes forthe 1/4-in.-sq. alignment dowel and forthe 8/32 attachment screw, but do not installthem yet. The stab, ailerons, fin and rudder are made from a 1/8 x 3/8 balsa framework. Build them overthe plans. Sand smooth,then sheetthem using 1/8-in Depron foam. Make sure they stay flat on the board while building. FUSELAGE CONSTRUCTION Cuttwo fuselage sides from 1/4-in. foam. Using the plan as a guide, draw centerlines on the inside of both sides forthe location of your firewall and AT A GLANCE MODEL: Sukhoi Su-26 DESIGNER: Mark Siranni WINGSPAN: 50.25 in. LENGTH: 50 in. WING AREA: 778 sq. in. WEIGHT: 3 lb., 8 oz. WING LOADING: 10.37 oz./sq. ft. formers 2, 3, and 4. Carefully measure the sides and cutthe hole in the side for the wing tube. Make sure the hole is the same on both sides. Using your motor as a guide, measure the distance from the front and epoxy your firewall in place on the right fuselage side, add the balsa triangles atthis time. Add former 2 along with Wing ribs with 1/8-in. ply doublers installed. Framed wing showing the wing tube and leading and trailing edge sheeting. Framed up tail surfaces made from 1/8 x 3/8 balsa. Firewall, landing-gear plate, F3 and 1/8- in. wing tube doubler shown. Wing is framed up overthe plans, and the ribs are pinned to reartrailing-edge jig.
March/April 2024 55 Sukhoi Su-26 Designed by Mark Sirianni, the Sukhoi Su-26 is made of Depron foam with balsa internal reinforcements. WS: 50.25 in.; Radio: 6-channel; Power: Hacker A30; LD 1; 3 sheets. To download the free, full-size plan, go to ModelAirplaneNews.com/su-26-plan. X0324A
56 ModelAirplaneNews.com CONSTRUCTION: SUKHOI SU-26 the 1/4-in. plywood landing gear plate and 1/8-in. ply landing gear doubler. Add the 1/4-in.-sq. battery tray rails to each side as perthe plan. Add former 4 to the right side. Add the 1/8-in. lite-ply tube doublerto each side. Letthings dry, make sure each formeris at 90 degrees to the side. When dry, epoxy the left side to the formers and firewall. Carefully align the sides making sure there is no twistin the body. Tape the sides together and keep flat on the top view to avoid any twist. Slide the wing tube through the fuselage to help keep things square, but don’t glue itin place yet. When dry, add a balsa triangle to left side of landing gear plate. BUILDING THE HATCH/CANOPY Using the plan as a guide, cutthe hatch section from both the left and right fuselage side. Cutthe hatch floorfrom 1/4-in. foam and glue the hatch sides to it. Then add the hatch back, keep things aligned on the fuselage as you build this section. Fill in the top ofthe hatch with foam and let dry. Cuttwo laminations of foam forthe fuselage rearturtledeck, glue in place. Add the battery floor and sides, adjustthe width according to the battery you will use. I used a 3S 2200mAh battery. Add the two laminations of foam forthe fuselage front. Add the two laminations of F1. Add the center1/4-in. foam fuselage floor and two laminations of foam for fuselage front. Let dry and then give it preliminary sand. FITTING THE WING TO THE FUSELAGE Cutthe outside portion ofthe wing tube in three sections,two to fitinto each wing half and one forthe fuselage. Draw a lightline down the outside of each fuselage side according to the plans. The wing has zero degrees incidence so it mustline up straight on this line. Glue the tube pieces into each wing half and let dry. Add the wing tube into the fuselage, sand slightly to make sure itis level. Slide the wing tube through the fuselage and slide the wings in place to see how they fit. Looking from the GEAR USED RADIO: Futaba Skysport 6A w/ FP-R 127DF receiver (futabausa. com), two HS-82MG servos, two HS-81 servos (hitecrcd.com) MOTOR: Hacker 500-watt A30 10 L V-4 (hackermotorusa.com) and 40A Jeti speed control (jetimodel.com) BATTERY: Admiral 3 cell 2200mAh LiPo (motionrc.com) PROP: 12 x 6E APC (apcprop.com) WING TUBE: Gator Hobbies no. GS 1500 (gator-rc.com) CARBON-FIBER LANDING GEAR: JTec no. JTC-S10 (jtecrc.com) Rightfuselage side showing centerthrustline. Fuselage sides joined and showing battery floor and battery sides. Hatch framed up and sanded to shape. Both wings attached to fuselage, 8/32 hold down screw and rear dowel shown. Tail surfaces shown after1/8 foam sheeting, sanded to shape.
March/April 2024 57 tail, you will be able to adjustthe trailing edge up or down to match the center line you drew down the fuselage sides. When you are sure thatthe wings are level, mark the holes forthe 1/4 dowel and 8/32 screw and drillthrough the fuselage sides. Add the dowel and screw to the wings and then add the 1/8 ply inside doubles to reinforce those holes. Testthe wings again to see how they fit, and make any adjustments atthis time. After you are sure everything fits, sheetthe center portion ofthe wings with 1/16 balsa. Add the aileron servo tray and then final sand the wing to shape. Add F4 and the 5/16 balsa pieces on the top and bottom ofthe center wing tube. Add the foam filler piece. Add a balsa block in the hatch that will align with the hatch cross brace on the fuselage. I cutthis in from the bottom. Drill a hole in this block to accommodate the 8/32 hold-down screw. Drill through the top cross brace and install a blind nut on the bottom to hold the hatch in place. Check the article photos for clarification. Once finished, final sand the entire fuselage,tail and ailerons and getready for finishing. I used Du-Bro pinned hinges for all surfaces. Installthe pushrods and cut your servo tray to fit your servos. I would hesitate from installing the servos in the rear ofthis model, with my setup; I had the servo tray as farforward as possible in orderto balance it properly. Add the fuselage foam bottom and final sand the fuselage to shape. FINISHING The wing can be covered in the material of your choice. I use UltraCote forthis model. The fuselage ,tail and ailerons need prepping for paint. The key to using this type of foam is to seal it with Minwax Polycrylic. The liquid really firms up the foam and allows you to sand in between coats for a stiff, smooth surface. I brushed on the Minwax directly from the can, no thinning needed. Apply light coats; you need to sealthe foam, but also be concerned about adding weight. Remember to keep the tail as light as possible. I painted the model with water-based hobby paint. I brushed on the paint, but you could spray it on if desired. All ofthe striping was done with paint. I added one final coat of Minwax to seal everything when finished. FINAL SETUP After everything is painted, install all of your servos, motor and battery and double-check the center of gravity location. My model balanced nicely with a 2200mAh pack and the servo tray in the location noted on the plans. FLYING This modelreally flie well on this motor and prop combination. Coming in at 3 lb., 8 oz. and with a wing loading of10.37 oz./sq. ft., itis light enough to take off quickly, and its landing speed is very slow. The rollrate is quite fast and it can do just about any maneuverthat you can think of. For me itis a great sport flierthat’s big enough to handle the wind, yet small enough to getin and out of a small field. With a little bit of work, you have a great flying modelthat will get some attention atthe field while saving a bunch of money with your hobby Wing bottom showing aileron servos and budget. landing gear. Finished right wing panel showing aileron and aileron servo base. Wings attached showing 8/32 screw and 1/4 rear dowel and servos.
58 ModelAirplaneNews.com HOW TO TEXT & PHOTOS BY TIM MCKAY BUILD FROM FOAM BOARD It’s inexpensive, user-friendly, and easy to repair!
March/April 2024 59 Foam board is an affordable and easy to use productthat can be employed to build a wide range of RC model aircraft. Let’s discuss a few techniques to get you started with building your firstfoam board RC airplane! FOAM BOARD BASICS You’ll first need to find a supply and type of foam board that works for you. Foam board is available from a variety of art and craft stores, such as Michaels and Hobby Lobby. I have had good results with Royal and Langnickel 20 x 30- inch sheets that are 3/16-inch thick (available through Amazon.) These sheets typically have a white (and sometimes black) paper covering that accepts paint with good results. I have learned from experience thatitis a good idea to keep the paper covering attached to the foam board. While the paper does add a bit of weight,the foam board tends to warp ifthe paperis removed, especially if it’s removed from just one side. A wide range of glues can be used forfoam board construction. By far the most common and useful is a hot glue gun. Simply take the gun, plug itin and insert a glue stick. The trigger will dispense a line of hot glue that bonds almostinstantly with another piece of foam board. I also use 5-minute epoxy forjoints that may need a bit more strength, such as joining wing panels or installing a motor firewall. Foam board is easy to cut and trim with a no.11 hobby knife, although any sharp cutter can be used. I usually draw the outline of whatever partI need directly onto the foam’s paper covering and then cutit out. This approach works well forfuselage sides, formers and tail surfaces. MAKING WINGS & STABILIZERS Wings can be formed by taking advantage ofthe ability ofthe foam to bend overitself and fold in half, using Tail section ofthe Boeing L-15 Scout. The tail boom is open on the bottom to help save weight aft ofthe center of gravity. Cabin section ofthe Boeing L-15 Scout showing the flat fuselage sides and motor mounted to plywood firewall.
60 ModelAirplaneNews.com HOWTO: BUILDFROM FOAM BOARD foam board strips as spars. Forthe wing spars, I glue two 1-inch-wide foam board strips on top of each other. Ithen glue this spar set onto the wing’s inner bottom surface, an inch or so back from the leading edge. Then I fold the wing’s upper surface overthe spar, gluing the wing top halfto the spar and then to the wing trailing edge. This makes a surprisingly strong wing and a convincing airfoil shape suitable for sport flying. If you plan for a wingspan of more than 30 inches, you can build two wing panels and join them together. I recommend using 1/16- or1/18-inch plywood dihedral braces to join the two halves. Five-minute epoxy works well for gluing these braces on both sides ofthe foam board spars inside the wing. For added strength, I use drywall reinforcementtape and epoxy glue on the wing joint. To keep things simple, I use wood dowels in the fuselage and rubber bands to attach the wings. Nylon bolts can be employed as wellto secure the wing in place. Tail surfaces forthe horizontal stabilizer and vertical fin can be made from the foam board and hot glued in place. As these are not structural members,this approach has worked fine for me. MAKING FUSELAGES Foam board lends itself well for making fuselages. I usually stick with structures that have flat sides. The fuselage outline can be drawn onto the foam board and cut with a sharp knife. Interiorformers can be cut out and hot glued to the inside ofthe fuselage. A variation you may consideris to build a profile fuselage. You will need to glue togethertwo layers ofthe 3/16-inch foam board. The fuselage tail section can get a bit “wiggly,” so consider adding some 1/16-inch plywood between the two foam board sides to provide stiffness. Receiver, battery, and servos can all be mounted on the fuselage sides. Aft view ofthe completed Boeing L-15 Scout showing the full span ailerons and tail section, with rubber bands holding the wing in place. Foam board can be used as fuselage formers. Note the opening cut outin each formerto allow for servo and controlrod installation. A hot glue gun does a greatjob with routine foam board gluing tasks. Note two pieces of 3/16-in. foam board for a wing spar, with top section folded overthe spar.
March/April 2024 61 Most of my models seem to come out a bittail-heavy. To counterthis, I often do not add fuselage bottom sections aft ofthe wing trailing edge and simply keep this area open. PLYWOOD & BALSA SECTIONS Although I use foam board forthe majority ofthe aircraft’s structure,there are some sections where it’s betterto use a stronger material. These areas include the motor mount/firewall, longer control surfaces, and the landing gear attachment area. Foam-board RC models should be flown with electric motors. The foam board is not as strong as a similar balsa structure where you have a variety of wood densities and strengths to work with. The use of a gas motor, with its higher weight and vibration would not work out well for a typical foam board structure. Plus it would be very hard to adequately fuel-proof a foam-board aircraft. The firewall must be plywood, either 1/16-inch for smaller models or1/8- inch forlarger ones. If in doubt go with 1/8-inch plywood forthe firewall. The small added weightis not an issue as you will likely be adding weightto the nose section anyhow to getthe proper center of gravity. Remember also to use bolts and nuts to attach the electric motor as screws will eventually work their way loose. The firewall must be securely glued to the fuselage sides. I use strips of1/16-inch plywood, glued to the inside fuselage sides,to butt up againstthe firewall fore and aftto reinforce the installation ofthe firewall. Long and narrow control surfaces, such as strip ailerons, should be made from balsa. I have used foam board for strip ailerons, butthese control surfaces always seem to warp in a short period oftime. I have used foam board for smaller and wider control surfaces such as elevators and rudders with no problems. You can use normal hinges on your foam birds in a similar manner as you do forthe balsa variants. Du-Bro plastic hinges work well once epoxied in place. I have also had good luck with using Scotch tape forthe hinges. The tape attaches wellto the foam board surface and seems to “disappear” from view once applied. Foam board can be used for smaller backyard flyers in either profile of full fuselage configurations. Paperis removed from the foam board to save weight. This is an example of using foam board to recreate classic designs such as the Lazy Bee slow flyer. Detailed view ofthe underside ofthe Boeing L-15 Scouttail boom and formers showing open lower surface to help save weight.
62 ModelAirplaneNews.com HOWTO: BUILDFROM FOAM BOARD LANDING GEAR The installation of landing gear will depend on your model. This is another area where a plywood plate glued onto the fuselage bottom is an absolute requirement. Landing gear can be formed from music wire with screw-on straps holding itin place. If you have a formed sheet metal gearin your parts bin,this is easy to screw into place as well. I make a lot of my foam board models withoutlanding gear. My models tend to weigh underthree pounds, so they’re suitable for a hand launch and showing minimal damage or scuffing with belly landings. The lack of landing gear speeds up the building process a bit. Additionally the models look realistic in the air with their “retracted gear” appearance. COVERING & PAINTING There are a range of covering and painting methods you can use to make yourfoam board model distinctive. Acrylic paint brushes on exceptionally well overthe paper covering ofthe foam board. Acrylic paints come in a wide range of colors, are odor-free and clean up with water. I have also used iron-on coverings. Irecommend the “lite” coverings as they shrink less than regular MonoKote and require less heatto apply. The best approach is to experiment with whatever covering you have on a scrap piece of foam board and see how it works out. Adhesive packing tape also works very well with foam board. If you look for “colored packing tape” on Amazon, you’ll find a wide range of colors and tape sizes. This tape is light weight and quite “sticky,” so it goes on the model well. Anothertype of covering tape that provides very nice results is metallic foil HVAC sealing tape from Home Depot. This tape has a shiny metallic look and is super easy to apply. The tape can be applied with the flat edge of a stick to produce a surprisingly smooth and realistic appearance of polished metal. BOTTOM LINE In summary, foam board is a great addition to yourrepertoire of RC model aircraft building techniques. Foam board is user-friendly and is the best approach to “building fast” an original prototype design. Changes are easy to make. And should yourlatest model not make it back to the landing field in one piece,repairs and rebuilds can occurin minimaltime. For more tips and techniques on building from foamboard, check out my videos at ModelAirplaneNews.com/ foam-board. Silver HVAC sealing tape is an easy to apply and realistic metallic finish for yourfoam board airplane. Note use of blue acrylic paintforthe cabin windows.
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64 ModelAirplaneNews.com As you become more proficient in your aerobatic ability, you will naturally begin to combine elements of different maneuvers within a single figure. One such maneuveris called the Cobra Roll with a Half-Roll Up and a Positive Snap Down. For new and experienced aerobatic pilots alike, this figure is demanding. It not only combines different orientations ofthe aircraft with upright and inverted flight but also requires you to focus on flying a triangular shape while performing a half-roll within the first half ofthe maneuver and a positive snap roll on the second. BEFORE WE BEGIN Itis beneficialto start with the control surface deflection amounts, exponential settings, and the center of gravity recommended by the manufacturer of a given aircraft. To precisely perform the feature ofthe month, two control surface deflection rates are recommended. On the low-rate setting,the model should be relatively docile. For most aerobatic models,this means thatthe aircraft should have about12 degrees of deflection on the aileron and elevator surface and roughly 30 degrees ofrudder deflection, all coupled with 20 percent exponential. Then, on the rate in which the snap roll will be performed, you should have about 30 degrees of aileron deflection, 20 degrees of elevator deflection, and about 35 degrees ofrudder deflection with 40 percent exponential. While the deflection and exponential amounts will differ on the aircraft being flown due to different control surface sizes, different centers of gravity settings, and so forth,this will serve as a starting point and can be changed to suit your needs. Exponential use is absolutely mandatory for accurate control ofthe aircraft. Using the correct exponential percentage will soften how the aircraft willreact around neutral stick, and as you move the control stick further, maximum travel can be obtained. Note, though,thatthe pointin which the rate changes will vary on the percentage of exponentialthatis used. COBRA ROLL OVERVIEW Align the aircraftin a mannerthatis parallelto the runway, in inverted level flight, into the wind, and at an altitude of about150 feetfor a standard 60-inch aerobatic model. Adjustthe altitude, as needed,to caterto the size ofthe aircraft being flown. Additionally,the entire figure should be centered on you. So the highest point ofthe figure, which will be the second radius and the transition from the 45-degree upline to the 45-degree downline, should be flown directly in front of you. As the aircraft approaches the runway, increase throttle so thatitis slightly above the cruising speed and only increase throttle before the push to a 45-degree climb is performed. Atthat point, you’ll need to increase the throttle anywhere between 75 and 100 percent and push to establish a 45-degree upline. It should be noted thatthe throttle amount will differ on the powerto-weightratio ofthe aircraft, so adjust this percentage as needed. Centered on the climb, you must execute a half-roll. Then, as the aircraftis almost directly in front of you, push to establish a 45-degree downline and decrease throttle to idle. Perform a positive snap roll on this segment, and pullto exitthe maneuverin uprightlevel flight atthe same altitude in which you began. Now, let’s divide this figure into five basic steps: STEP 1: Increase throttle to approximately 60 percent, and orient the aircraft so thatitis parallelto the runway and traveling into the wind. On low rates, perform a half-rollto inverted flight. Because the model is now inverted, it will be necessary to hold a slight amount of down-elevatorto maintain altitude. When the aircraftis about 300 feet away, increase throttle to 75 percent and push 1/8 of a loop to establish a 45-degree climb. STEPS 2 & 3: On the 45-degree climb, perform a half-rollthat will be centered on the line segment. Roll direction is not critical, butitis importantto focus on keeping a constantrollrate throughout the half-roll segment. Additionally, you’ll need to apply elevatorto maintain the 45-degree climb afterthe roll. Centered on you, perform the gradual 90-degree push from the 45-degree climb to a MADE EASY AEROBATICS BY JOHN GLEZELLIS ILLUSTRATION BY SINELAB ADVANCED COBRA ROLL A half-roll up and a positive snap down really wows the crowd!
March/April 2024 65 EXIT straight and level atthe same altitude and direction as the entry. 45-degree descent. During the push, gradually decrease throttle so that once the 45-degree downline is established,the throttle will be atthe idle position. STEP 4: If using the control recommendations mentioned earlier, activate the snap-rollrate. Fly a positive snap roll in the center ofthe 45-degree downline. A positive snap rollrequires up-elevator with aileron and rudder inputin the same direction. After you’re proficientin the snap roll, you can “unload” the maneuver by applying elevatorto start, and afterthe plane changes pitch, apply aileron and rudder input while releasing elevator. Regardless of which method you use, release control inputs forthe snap rollto exit on the 45-degree line and return to the low-rate setting. STEP 5: To complete the figure, pull1/8 of an inside loop to uprightlevel flight at exactly the same altitude at which the maneuver began and increase throttle to 60 percentto maintain a constant speed. Now, prepare to turn around and perform the maneuver again. After all, practice makes perfect! If itis difficultto change rates throughoutthe figure, you may need to fly the maneuver on the rate that has enough control deflection forthe snap roll. In this case, increase exponentialto dampen the overall feel ofthe aircraft and fly the maneuver smoothly. FINAL THOUGHTS This stunt can be quite difficultto perform as it contains many individual elements. To be successful, break down each element until you’ve perfected it, and take advantage of every benefit your computerradio has to offer. Above all else,rememberto seek the advice of fellow experienced aerobatic enthusiasts—and mostimportant, always rememberto have fun. Enterthe maneuver from straight and level inverted flight. Push elevator to establish a 45-degree upline. 1 Atthe top, push down-elevator and establish a 45-degree downline. 3 Midway on the upline, perform a halfroll from inverted flight to upright. Continue the 45-degree upline. 2 Midway in the downline, perform a positive snap roll and then continue the 45-degree downline. 4 Atthe bottom ofthe downline, pull upelevator and establish a straight, horizontal line to exitthe maneuver. 5 THE ENTIRE FIGURE SHOULD BE CENTERED ON YOU. SO THE HIGHEST POINT OF THE FIGURE, WHICH WILL BE THE SECOND RADIUS AND THE 45-DEGREE DOWNLINE, SHOULD BE FLOWN DIRECTLY IN FRONT OF YOU.
66 ModelAirplaneNews.com HANGAR TALK BY DEBRA CLEGHORN PHOTOS COURTESY CALIFORNIA INSTITUTE OF TECHNOLOGY REAL-LIFE TRANSFORMER Introducing the Morphobot Called the "M4," or Multi-Modal Mobility Morphobot,this hightech robot can drive, fly, crawl, and stand upright! With NASA fielding candidates for next-generation Mars rovers,researchers atthe California Institute of Technology and Northeastern University have been busy designing the M4. This transformer can move like any four-wheel-drive vehicle butthen quickly extend its wheels, which also house propellers,to become a quadcopterthat can reach speeds up to 40 mph. It can even balance itself on two wheels and use two thrusters to propel itself forward! The M4 has eight modes: fly,roll, crawl, crouch, balance,tumble, scout, and loco-manipulate. It can climb steep slopes of up to 45 degrees and go into balance mode when traversing rough terrain with large obstacles. This robot uses artificial intelligence to scoutthe environment and can autonomously select which mode of movementis most effective. A lead developer, Alireza Ramezani said,"To the best of my knowledge––I’ve been in this field 15 years––I cannotthink of any robot with this level of locomotion plasticity and number of modes that we have showcased." The M4’s level of dexterity and movement flexibility could be useful for exploring the dusty surface of Mars or even on a rescue mission on Earth. We hope to see the M4 in action on the Red Planet!
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