RCU Review: Great Planes U-Can-Do SF 3D GP/EP

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    Contributed by: Jerry Festa | Published: May 2014 | Views: 39419 | email icon Email this Article | PDFpdf icon
    Aeroworks Trainer GT, An RCU Review


    Dealer information

    Great Planes
    Model Distributors

    2904 Research Road
    Champaign, IL 61826


    The long series of “U-Can-Do” aircraft spans quite a few years and includes a large variety of sizes as well as engine/motor options. Notice the ‘GP/EP’ notation in the title of this plane. That stands for ‘gas powered/electric powered’. None of the previous U-Can-Do’s was designed for electric power while the engine for those nitro-powered planes ranged from .40 thru 1.20! Many feel this series of planes only became better as the size increased. Well this offering is the first of this series to offer SFG (Side Force Generators) so it will be an interesting comparison as we have a couple of larger U-Can-Do’s still flying in our club!

    This plane appears to be the latest in a line of ARF’s that can be assembled with either a nitro-powered engine or an electric motor to compliment Great Planes Escapade Sport GP/EP ARF 52.5" and Extra 300SP GP/EP ARF 55".



    • Flying ability is excellent
    • Assembly straight forward
    • Designed for glow or electric power
    • Carbon fiber tubes reinforce all pushrods
    • Good color contrast
    • Part fit was excellent
    • “Spinner Jig” makes mounting cowl easier
    • Total weight was much less than advertized!


    • Wing leading edge dowels 5/16” but holes in wing were ¼”
    • The control horn’s pre-drilled holes could not be found
    • The tail wheel attachment method places stress on the rudder
    • Some steps/procedure in the manual was already done
    • You have to work a lot for knife-edge flight
    • Cost may be a bit prohibitive for some
    • Small nose gear set screw inadequate for nose gear stearing

    Name: U-Can-Do SF 3D GP/EP

    Wingspan: 59" (1500mm)
    Length: 58" (1475mm)
    Weight: 6.5 - 7.25 lb (2950 - 3290g)
    Wing Area: 912 sq in (58.8 sq dm)
    Wing Loading: 16 - 18 oz/sq ft (49 - 55 g/sq dm)
    Center of Gravity (CG): 5-1/2" (140mm) back from the leading edge of the wing at the fuselage side
    Control Throws: Low Rate High Rate 3D
    Elevator 3/4" (19mm) 11° 1" (25mm) 15° 2-5/16" (59mm)36°
    Rudder 1-1/8" (29mm) 10° 2-1/2" (64mm) 23° 4" (102mm) 39°
    Ailerons 5/8" (16mm) 8° 15/16" (24mm) 12° 1-1/2" (38mm) 20°


    Electric Set-Up
    (1) Electric Motor: RimFire 80 (50-55-500) Outrunner Brushless**A battery lead extension is recommended if installing a brushless motor.
    (1) ESC: 60A
    (1) 6" (152mm) Extension: For ESC
    4 Channel Radio (minimum) and Receiver
    4 Standard Servos
    4S-5S 3350 mAh LiPo Battery and LiPo Charger
    Thread Locking Compound and Thin CA
    Various Shop Tools
    Glow Powered Set-Up
    Engine: .55 - .65 cu in (9 -10.5cc) 2-stroke glow, OR .82 cu in (13.5cc) 4-stroke engine
    4 Channel Radio (minimum) and Receiver
    5 Standard Servos
    Thread Locking Compound and Thin CA
    Various Shop Tools
    Glow Engine Field Equipment

    Items Needed To Complete Plane:

    Radio: 4-channel, standard size receiver
    Servos: Five with a minimum of 72 oz/in torque
    (2) Servo Extensions 12" (305mm): for aileron servos
    (3) Servo Extensions 24" (610mm): for tail servos
    (1) Y-Harness: To connect aileron servos to the receiver
    (1) Reversing Y-Harness: for elevator servos if TX programming isn’t available
    (1) Receiver Battery: 4.8V NiMH if using brushless motor OR 4.8V NiMH or 6.6V LiFe if using glow engine


    Tools and Materials Needed To Assemble Plane

    Allen wrenches US and Metric.
    Electric drill and selection of bits

    Razor saw

    Flat head screwdriver

    Hobby heat gun

    Hobby iron and covering sock

    Masking tape

    Modeling knife

    Needle nose pliers or crimping tool

    Paper towels

    Pen, pencil or felt tipped marker

    Phillips screwdriver

    Rubbing alcohol

    Ruler and tape measure


    T pins

    Wire Cutters

    Blue Loctite

    CA kicker (optional)

    Thick, Thin and Medium CA

    Epoxy, 30-minute

    Rubbing alcohol



    Lets get started


    It took me back at how light the large box weighed! Therefore after opening, unpack aging and taking umpteen pictures, all the major components were placed on a scale. The wing, tail feathers, and fuselage came out to a very respectable weight of 2 pounds 13.9 oz. None of the Monokote really needed any attention but the covering iron was fired up while that blasted masking tape that holds the elevator to the stabilizer was removed. It is just a personal thing with me, but when you remove those strips of tape, the covering is lifted at those places and that detracts from the beautiful covering job done at the factory!


    All the hardware was neatly packed in a separate box. The nuts and bolts were all SAE and appeared to be of high quality as were the hinges (for the tail feathers). Other hardware included the fuel tank, spinner and of course the wheels. Blind nuts were already installed in the fiberglass wheel pants and inside the fuselage for the wing bolts. Also supplied was a nylon engine mount as well as a motor box for the installation of an electric motor.


    The hinge line/gap for the ailerons was very small which was good because the ailerons were already hinged and glued into place!



    What’s New?

    When I start a project it is wise to take note of what is new as far as parts or procedure. What first was observed was the use of carbon fiber tube reinforcement for all the pushrods! Then I noticed the elevator pushrods are on top of the horizontal stabilizer which will require a pull motion to move the elevator upward. I’m happy to report the wing bolts have a nice large washer molded in place which might save the wing from some slipping screwdrivers. Maybe you don’t know this, but your 4-way ‘glow plug’ wrench has a perfect match for the wing bolts. Try it; I think you will like it. Speaking of the wing, the leading edge ‘dowels are molded nylon and are epoxied into place.


    The manual consists of 32 pages and includes at least one picture for each step. My first impression was that the text seemed somewhat more detailed than necessary considering the clientele who would be assembling this aircraft. After reading the entire manual (before construction started) I felt there was some very good advice offered and well worth the read. I especially liked the page that explained proper pushrod arrangement(s) and of course the pages explaining how to do some of those 3D maneuvers! The entire manual can be downloaded or read on Great Planes website: http://manuals.hobbico.com/gpm/gpma1272-manual.pdf.


    The suggested assembly progression is as follows: ailerons; wing; tail feathers; landing gear; motor/engine; tank; receiver. The only modification to this sequence was to install the OS Max 65AX first, then remove it and continue with the manual’s recommended succession of steps. Through the years I have found it to be easier to mount the engine with the tail-less fuselage resting on the floor and the firewall about waist height.

    As was previously mentioned, slide the carbon fiber tubes over the pushrods BEFORE you make that final 90 degree bend for the servo arm. If you fail to follow this procedure and have the pushrod already bent, you can force the carbon fiber tube over the threaded end – and it will take some force –the tube can still be epoxied in place, but it is better to follow directions!

    The Belly pan has to be epoxied in place and maybe a suggestion can be made as how to glue it in place and at the same time not let ugly, yellowing epoxy ruin the wing/pan joint. When you are done mixing up your 30 minute epoxy for this task, take a toothpick and dip it in some (Blue) Testor’s Plastic paint and use that for your new mixing stick. Your epoxy is now blue and when you attach the belly pan to the wing, use some paper towels and rubbing alcohol to wipe off any excess glue. Any remaining glue will be blue!


    The ¼-20 nylon wing bolts are well designed in that they have a large washer molded into place. In addition, you can use a 4-way wrench to secure the wing. The bolts are recessed through the belly pan.

    The tail feathers can be glued into position without having to remove a portion of the covering to obtain a good wood-to-wood contact point. Nonetheless, the instruction booklet does a great job of explaining how to remove the covering and if you have never done it the correct way (with a soldering iron or hot knife) it would be well worth the time to read that section. Tower does offer a great knife for this task: Walnut Hollow Hot Knife (part # LXZTZ8).

    A personal point of minor irritation is Great Planes method of attaching the tailwheel – which I should add - can frequently be found on the majority of sport ARFs. With their method (the tailwheel assembly glued into the rudder) the majority of the shock should the tail impact the ground on landings will be borne by the rudder. Perhaps if this wasn’t a review plane, Great Planes’ manner of installing the tailwheel would be replaced with an alternative system. Enough said!


    Just be careful where you place your control horn on the rudder as the tailwheel assembly could interfere with the control horn’s machine screws (look closely and you will see mine had to be moved upward to permit the tail wheel wire space to enter the rudder.

    The elevator and rudder control horns were attached to their respective surfaces before being positioned on the fuselage. I never could find those ‘pre-drilled’ holes when attaching any of the control horns, but it isn’t rocket science to install them.

    In order to have the elevator servos working together require one of two things: 1) Computerized transmitter that will enable ‘Master/Slave’ arrangement for the two elevator servos, or 2) a reversing “Y” connector. My Futaba 6EX transmitter could electronically arrange this with one caveat: the slave servo could not be individually trimmed with the transmitter, therefore a “Y” connector (Futaba SR-10 Dual Servo Reverser; part # LXANF2) was utilized.

    The only hardware replacement for the U-Can-Do was for personal reasons: replaced the motor mount and engine mounting bolts with socket head machine screws. The supplied nylon motor mount was drilled and tapped for 6-32 bolts using Du-Bro’s drill and tap set.


    Even though this is not an electric powered review, I would be amiss if I didn’t mention the assembled ‘complex’ motor mount that was supplied. The manual steps you through this assembly, but it was already done for you! And to make certain your cowl is correctly lined up, a special “jig” was supplied and mounted to the firewall so you can mount your cowl without fear of being crooked.


    The cavity in the bottom of the fuselage was large enough for the muffler and no additional work was necessary to fit the muffler to the engine/plane. This size engine/muffler did require removal of some of the fiberglass cowl, whereas according to the manual, the OS Max 55 would not require as much removal in the muffler area.

    Mounting the cowl required some of the fiberglass to be removed to clear the cylinder head and some nearby spaces. When it came to place the cowl on the plane (with the engine in place) it quickly became apparent it wasn’t going to fit over the engine. Many different angles were tried and once I heard some of the cowl cracking and groaning, a new solution had to be found.


    After about an hour of fritting and complaining, George was asked what he would do. Good Ole’ George came through again….he suggested I open up the bottom of the cowl giving the cowl some additional flexibility and sure enough – it fit! The 65AX muffler requires a lot of room, whereas (according to the manual) the 55AX‘s muffler fits inside the cowl. So some additional material was removed to accept the muffler, needle valve and some space for the pressure line from the tank to the muffler.


    Engine Spotlight

    The supplied engine was an O.S. Max 65AX that included the muffler, installed glow plug (OS #8) and a needle valve extension. From pervious experiences with this engine, the 65AX is a natural choice for this U-Can-Do. The angled back high speed needle valve makes engine adjustments much safer than previous versions. With a maximum RPM of 12,000 the thrust will far exceed the weight and drag of the U-Can-Do. An APC 12.75 x 3.75; 13x4w and Top Flite 13 x 6 were used at one time or another for this plane.


    Finishing Touches
    We decided to remove the glow plug and try with an electric starter. That worked – sort of – because the engine was too tight at TDC and bogged down the starter. New starter (18 volts) was tried and for 20-30 seconds the engine was ‘run’ by the starter and couldn’t start because the glow plug was still sitting on the stand.

    Put the plug in and tried again and this time was success. We ran one tank trough stopping and starting and running rich at 3000-4000K. Second tank was consumed doing about the same thing – with Richard (or local ‘Engine guru’) making all sorts of minor adjustments (1/8th turn here, 1/8th turn there) on both the high end and low end. Engine was running nice and stable now, so a third tank of 10% PowerMaster fuel was added to the routine.

    With the engine running on the rich side, the cowl off and no more excuses, it was time to fly. Overcast sky, little wind and bit cooler than normal (55 degrees) the OS 65AX started with just a touch of the starter.


    Taking off from left to right, the U-Can-Do tracked straight but needed some right rudder until the tail came off the dirt runway. A gentle climb out was interrupted with a roller coaster dip and climb until a slight amount of up trim was added. Then the flight was at least flying level. The ailerons were very sensitive and thinking I was flying with high rates, flipped the switch to what I thought was low when in reality it was already on low rates!


    A couple of laps around the field the ailerons became friendlier and various maneuvers were tried: spins, loops and of course rolls were found to be excellent. The “Peanut Gallery” was breathing down my neck and I could feel their desire to fly this plane, so Steve got the first shot and tried some “high” hovering and liked the way it handled and thought the plane was a winner. Then Rich took the transmitter and was very impressed with the way the plane handled – but” is very sensitive” (it should be Rich because it was on high rates!). After doing a variety of maneuvers, known only to him, the engine ran out of fuel and Rich brought it in with a VERY slow approach and did an excellent 3-point landing, almost ending up at where the gaggle of pilots, err “Peanut Gallery” huddled around Rich. As slow as he was going, the plane didn’t even hint at snapping! We were all impressed.


    The next flight saw some excitement – while doing some knife edge the canopy popped up and a quick landing was made. No damage, but some clear tape was added to keep the canopy where it belonged. Remember the cowl was off which assists in holding the canopy in place.

    I made another flight and some observations were noted. Every time a vertical climb was initiated, the engine torque would pull the plane strongly to the left and whereas the rudder on this plane is very effective, some right rudder was needed for a clean up line. I really became more comfortable with the low rate settings, but rolls with high rates are unbelievably fast!

    Stalls will result in a dropping of the left wing after mushing along will full up. Spins are tight if you can get a clean stall first. All vertical maneuvers are unlimited as the OS 65AX will pull this plane into the next solar system if you let it. We then switched to a 13/4W APC prop.


    The next day three flights were made and some pictures with the cowl on were taken while the plane was in flight. We tried some expo and dual rate adjustments on the ailerons and elevator so the high rates became equal to the low rates from the day before and cut the low rates to ½ of their original settings. I didn’t like it that way……but it was George’s (AKA Grouchy George) turn so after using up ½ of the tank, the transmitter was passed to him while on low rates..…within 10 seconds, he flicked the switch to high rates – so that confirmed the settings – try the low rates as specified in the manual for your first flights and you may want to add some, not much expo.


    On the next flight a problem developed in that the canopy wanted to depart from the fuselage. It seems the attachment method needed more attention from the installer (me). With the cowl on (and I think I installed it too tight against the top of the firewall), it was difficult to slide forward, but it could be done (that was not the problem). The problem was that it was very difficult to slide BACK far enough to engage the two locking pins. The solution was to remove a very small amount of the locking pins permitting the canopy hatch to lock into place.


    Jim Talmadge has owned and flown all three sizes of the U-Can-Do (.40, .60, and 1.20) so he was eager to try this one. His conclusion is two-fold….one; he feels it flies better than the .40 size (but not as good as the 1.20) and two; he is going to get one (and put on an OS75)! He tried many of his 3D maneuvers and was impressed with its flying abilities. He was nice enough to bring his .60 sized U-Can-Do so some pictures could be made showing the size relationship between the two planes.

    The next day Jessie Campbell showed up and I asked him to wring out this plane. Jessie loves flying all sorts of 3D maneuvers so he tried them all. The good news is that the U-Can-Do did everything he asked of it in spite of the plane being slightly nose heavy. Jessie like the plane! I don’t think the plane flew more than 2-3 seconds in a level flight – he was all over the sky doing some maneuvers I really don’t know how to describe. And notice the canopy stayed on! Jessie, Jim, Steve and Luis all said knife-edge was difficult as the plane wanted to keep rolling…but as Jessie said, “You really have to work” to keep a long knife-edge. But Jim stated this plane is the best of all the U-Can-Do aircraft when it comes to knife-edge, so your former U-Can-Do owners take note!






    I believe this plane is a keeper and the engine/plane combination is right on. Everyone at the field had the same or similar comment in that this U-Can-Do is one beautiful looking bird. This plane is made for 3-D maneuvers so speed is not your friend, yet with the OS Max 65AX at full power (11,400 RPM and using Omega 20-20 Heli fuel and 13/4W APC) the plane showed no high speed flutter or twitching. Take-offs can be as short as you like, landings very slow, and everything in between can be as wild as you wish! The more flights I fly, the stronger the OS Max becomes – Rich said the engine is flying with a smile on its face, leaving a nice smoke trail. I’d recommend you start with the factory settings for control throws and go from there. Yep, this plane is a keeper – Great Planes, yadidgood!



    Great Planes
    Model Distributors

    2904 Research Road
    Champaign, IL 61826
    Website: www.greatplanes.com

    Distributed through
    2904 Research Rd
    Champaign, IL 61822
    Phone: 1-217-398-8970

    Distributed through
    Great Planes
    Model Distributors

    2904 Research Road
    Champaign, IL 61826
    Website: www.greatplanes.com

    Comments on RCU Review: Great Planes U-Can-Do SF 3D GP/EP

    Posted by: festajg on 05/31/2014
    Well organized, thorough review.
    Posted by: griesel on 10/31/2015
    On aerobatics it is not as good as a Ventique 60E. However due to the thick wings it has very gentle stall characteristics. It is very easy to land. When building it as an electric, relocate the switch location (if used) as it interferes with the main battery.
    Page: 1
    The comments, observations and conclusions made in this review are solely with respect to the particular item the editor reviewed and may not apply generally to similar products by the manufacturer. We cannot be responsible for any manufacturer defects in workmanship or other deficiencies in products like the one featured in the review.

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