|Wing Area:||290 sq in|
|Transmitter:||Futaba 9CAPS with TM-8 2.4GHz module|
|Battery:||ElectriFly 20c 3s 3200|
|Motor:||ElectriFly RimFire 35-36-1200kv|
|ESC:||ElectriFly SS-45 amp ESC|
|Available From:||Tower Hobbies|
I have been fascinated with heavy metal birds since I can remember. I can recall when I first got interested in the hobby thinking that I would have a whole fleet of warbirds (and jets) starting the day after my first solo flight. Not soon after, I had my first Mustang.
When the Great Planes P-47 came up for review I put my name in the hat immediately. I have owned many warbirds in my modeling career and have found that the designs have gotten easier to fly with advances in building materials and techniques. The Great Planes P-47 is designed with electric power as an option, not an afterthought. That, along with its smaller size, further interested me. Having experienced some of the new Great Planes offerings, I figured this would be the perfect chance to review a non-foam warbird that could also be flown as an everyday aircraft. An opportunity that proved to be right on the money!
The Great Planes P-47 kit box arrived inside of another very sturdy shipping box. The contents of the kit box were individually wrapped and held in place with tape to prevent movement and damage during shipping.
Items needed for completion of electric version:
My first impression of the major subassemblies was that they were very strong and sturdy without being overweight. The Monokote was applied perfectly without a single wrinkle or bubble. The painted parts had nice clean tape lines, and the color match was near perfect. The fiberglass cowl was very sturdy without being too heavy. The decals felt nice and thick and the print was clean with sharp lines. A quick lift of one of the corners of the decal sheet showed that the clear section of the decal sheet was indeed clear and not yellowed. The miscellaneous parts were about what I expected, but what I didn't expect was a very nice aluminum spinner hub... nice touch! Another thing I didn't expect (and I almost missed it at first glance because they were done so well) were factory hinged and glued control surfaces. Great Planes must know that's one of my least favorite building chores.
The battery hatch had a gap along the left side of the fuselage. At first I thought the gap was caused by the magnet coming out of its retaining pocket preventing the hatch from closing down, but the gap was still there after I placed the magnet back into its retaining pocket and replaced the hatch. A quick push on the back corner of the hatch revealed that the hatch was warped.
A quick glance through the building sequence proved once again that Great Planes knows how to write an instruction manual. The black and white pictures are clear, and the corresponding text is almost always easy to follow. The manual outlines the steps for building both the electric and glow version of the aircraft along with a handful of tips and safety precautions.
The first step in preparing the wing panel is to install the aileron servos. The aileron servos are mounted with screws to the underside of the servo hatch after wood blocks are glued to it. An outline of the servo block placement is etched on the hatch for the recommended servos. Before mounting the servo/hatch assembly, an aileron extension wire must be added to the servo to make it to the end of each wing panel. Each hatch/servo assembly is then mounted to the wing with 4 2mm wood screws.
After I had the servo assemblies mounted in the wing I began to prepare for the linkage installation. I mounted the control horns as directed, and then went to attach the control rods. Although the push rod clevises were there, the aileron push rods were missing. Fortunately, I have a pile of push rods and clevises that I draw from if I need a spare. I installed 2-56 push rods with Z-bends on the servo control horns and Dubro metal clevises on the aileron control horns (the manual recommends using nylon clevises and nylon Fastlinks to secure the push rods).
The next section of the manual is dedicated to joining the wing. While preparing to do just that, I ran into an interesting issue. As supplied from the factory, each wing panel has a hole cut in it that allows the aileron extension wires to exit the wing panel just short of the root rib. On my kit, the holes were cut in the BOTTOM of the wing panel instead of the top, thus sending the aileron extension wires into where the belly pan will be mounted instead of into the fuselage.
Although the aileron extension holes were on the wrong side of the wing panels, the fix couldn't have been easier. I simply put a hole in the top of each wing panel, and in a matter of seconds was finished with the modification. In the meantime, I had glued the two plywood wing joiners together and test fit them into one of the wing panels.
After I was sure that the plywood brace would fit properly into both wing panels, I glued them together with epoxy. Next, a hardwood wing bolt plate is added the trailing edge of the wing at the root.
At this point, the manual recommends installing the wing temporarily to help in properly aligning the stabilizer. Unfortunately, I couldn't get my wing to lay flat in the wing saddle. It was quickly apparent that the wing tab on the front of the wing was binding with its corresponding slot in the fuselage former. I decided to cut a little bit of the tab away to allow the wing to lay flat.
The vertical stab and horizontal fin come factory hinged (and glued) and even have the Monokote cut away from the surfaces at the glue contact points. I am spoiled, I now expect all of my ARFs to come like this!
Before mounting the stab and fin, a small piece of balsa must be removed from the stab slot. After completing this step, I test fit the stab and fin in their respective slots. What a relief! Everything looked perfectly square, which isn't always the case with ARFs.
Luckily I had read through the entire manual before starting the assembly process. Later in the manual, Great Planes recommends and supplies parts for a tail skid, but I decided against the tail skid in favor of a tail wheel for two reasons: I fly at a field with a 1000ft paved runway, and this is a P-47 not a Fokker DR.1. It just isn't right! I bent a piece of music wire using the "this looks about right" method and added a tail wheel from the spare parts box. The reason I mention it now is that if you decide to add a tail wheel it needs to be added to the rudder before mounting the fin.
The tail wheel installation included the drilling of a hole into the rudder to support the tail wheel wire. A channel must then be cut into the rudder from the hole to the bottom of the rudder. The tail wheel wire is then glued into the hole in the rudder while sitting flush in the channel. A CA hinge is used at the bottom of the rudder (next to the tail wheel wire for my modification) to provide extra support when installed on the fuselage.
The installation of the stab is very straightforward and is made easier by the inclusion of a center mark on the firewall. With the aid of a piece of string and a pin, the center mark is used to measure equal distance from the center point to the ends of the stab. After the stab was aligned correctly, I secured it in place permanently with thin CA. After the stab and elevator were installed, I installed the fin with thin CA into a channel on the top of the rear of the fuselage while using a building square to make sure everything lined up.
To prepare for the installation of the control horns, I inserted the rudder and elevator push rods into the push rod exit slots from the outside of the fuselage. The control horns were then placed on the Z-bend in the push rod. The push rods are used to align the control horns properly, without binding, over the hinge line. After I was satisfied with the alignment, I drilled holes for the screws and mounted the control horns according to the instructions.
The recommended servos are easily installed into the factory installed servo tray in the fuselage. The extra servo arms must be cut off of the servo control horns so they don't bind with each other or the fuselage wall. I then centered the servos and secured the push rods to the servo control horn with the supplied screw-lock push rod connectors.
Since I was building the Electric version of the P-47, I needed to modify the firewall and hatch to allow cooling air to enter the fuselage and battery compartment. The cooling hole cutouts are easily removed because they are perforated from the factory.
Before The power system can be mounted to the fuse, a motor mount/ adapter box must be built. I used thin and thick CA to glue the lite plywood pieces together.
The recommended motor (Rimfire 35-36-1200kv with included x-mount) is easily mounted to the firewall with machine screws into the previously installed blind nuts. Next, I mounted the Electrifly SS-45 speed controller to the side of the motor mount with Velcro.
A cooling air exit hole is designed into the airframe and is utilized for the electric version. I needed to cut the Monokote away from the hole in the bottom of the fuselage. After the Monokote was cut away it was simply a matter of roughing up the plastic rear scoop and the corresponding Monokote with sand paper and gluing the scoop on with thick CA.
Since I had a few issues with my kit, I decided to send an e-mail to my contact at Great Planes to let them know about the hatch, the wing extension holes and the missing push rods. Within a day I had an e-mail response requesting pictures. When I sent the pictures in I also included my phone number in case they wanted clarification. I received a phone call from a Great Planes representative. He was apologetic as we discussed the issues I had seen with my kit. Before calling he had gone through a number of kits that they currently had in stock and did not find any of the issues I had with my kit. My kit was one of the first from the first run. He offered to send a replacement kit right away.
I was apprehensive about replacing my kit with a new one for a number of reasons. I wanted to finish the kit I had received because many people think reviewers get special kits, which was certainly not the case. And I was over halfway done and didn't want to start over! I explained these reasons to the Great Planes representative. I came to an agreement with the Great Planes representative; I would continue the build with my original kit, and he would send out another kit that I could use as a reference to see another off the shelf kit with these issues resolved. I could also use the kit for replacement parts for the hatch, wing panels and push rods.
The second P-47 kit that I received did not have any of the issues that I experienced with the first kit.
Before the cowl could be mounted, I needed to install hardwood blocks to the firewall with thick CA. These serve as anchor points for screws that go through the cowl.
The manual describes a method for lining up and installing the cowl that makes it rather easy to get it right. First, I attached 4 pieces of paper down the front of fuselage and over the cowl blocks. I pushed the paper around the blocks to give the impression of the blocks. Once I had the outline of the blocks, it was easy to find the center and mark it for the location where the holes will be drilled for the cowl mounting screws.
Next, I slid the cowl under the templates, centered the cowl, and drilled holes through the cowl using the previously marked hole locations in the template as a guide. I installed the cowl with 4 wood screws.
In order to fix the warped hatch, I removed part of the hatch center former and soaked the underside of the hatch with glass cleaner. I then twisted the hatch and dried it with my heat gun. After doing this a few times, I had the desired shape. I sealed the wood with thin CA to help maintain the new shape.
There isn't much to do to finish the radio installation once you make it to this point. I simply installed my Futaba FASST receiver to the bottom of the battery tray with Velcro and hooked up the servos, servo extensions, and speed controller lead. I test fit the battery at this point to make sure it fit well under the hatch.
NOTE: You must be careful when removing the flight battery. I accidentally hit the former when removing the flight battery and it split. The fact that I previously had a pin stuck in this location to measure my tail surface distance (as recommended in the manual) contributed to the weak former. After removing the pin from the stab measuring step, I would recommend adding some thin CA to the hole to strengthen the former.
The canopy came cut, painted perfectly and ready for installation, a nice touch since one of my least favorite things to do is to cut canopies from large pieces of excess plastic. One thing that was a little disappointing at this stage was the cockpit area. The cockpit was just a simple cutout that was covered with the same colored Monokote as the stripe that ran across the top of the fuselage. I realize this is a sport scale version of a P-47 but I would have liked to at least seen a instrument panel decal included to add to the cockpit.
The instruction manual recommends gluing the canopy to the cockpit area with canopy glue. I chose to install my canopy by using 1/4 inch silver vinyl pinstripe around the canopy frame. It makes for a neat installation and allows the canopy to be easily removed if needed.
The P-47 includes optional landing gear for those that would rather take off from the ground than hand launch. With a 1000ft paved runway at my field, its hard to pass up the opportunity to take off with gear, especially on a maiden flight. I will take the gear off after the plane is trimmed and report the differences in the flight section of this review.
Before installing the landing gear the Monokote must be removed from the gear slots on the bottom of the wing. The gear assemblies are inserted into a hole in the wing and then slid into the gear rail slots. The wire is then held into the wing with landing gear straps and wood screws.
The belly pan that covers the bottom of the wing is also factory cut and painted. I installed the belly pan support pieces to the belly pan with thick CA. After the support pieces are installed, the belly pan is simply glued to the bottom of the wing between the wing saddle opening on the fuselage. I also added some vinyl pinstripe to the edges of the belly pan to cover the joint.
With the majority of the airframe complete there are only a few things left to do to add that last bit of realism. The kit comes with eight pieces of factory cut carbon rod that simulates the gun ports in the wings. The rods are simply glued into factory drilled holes in the leading edge of each wing panel.
The literature that came with the motor recommended a wide range of props. I decided to use a 10x7 APC-E prop which is held on by a beautifully machined and included aluminum propeller hub.
The included decals are self-adhesive. I was glad to see that the clear sections were not yellowed or hazy. They are also a little thicker (tougher) than most decals that are included in kits these days.
The recommended C.G. is located 2-1/4" [57mm] back from the leading edge of the wing. The Control throws are listed in the picture below. I did not have to add any weight to the completed airframe to get it to balance properly. I simply slid the battery up in the battery tray to achieve the proper C.G.
With the battery fully charged (12.61 volts and 62 degrees), I hooked up my trusty E-meter and applied full throttle. I was seeing 389 watts at 34.59 amps (When the battery warms up, I expect to see a little more power). The voltage of the battery at this power level was 11.25 volts. That's 138.3 watts per pound. With that kind of power I expected to see very spirited flight!
With the addition of a tail wheel, The P-47 taxied out to the runway with little problem. The wind was blowing steady down the runway with gusts to 12mph. I slowly advanced the throttle in preparation for the takeoff run. The plane started to pull a little left so I fed in some right rudder. I advanced the throttle again and the tail started to lift off the ground. With the tail up the plane was more easily controlled on the ground. I steered the P-47 straight down the runway and fed in some up elevator until it lifted off. The P-47 was pulling slightly left as I gained altitude. I made a banked left turn and then prepared for the rest of the flight. The P-47 needed a couple of clicks of right aileron and a couple of clicks of down elevator to fly level. I found the control throws as recommended in the manual to be just about perfect. Subsequent takeoffs have proven to be a non event as long as I ease into the throttle on the takeoff run and use some corrective rudder. If I advance the throttle too fast the P-47 has a tendency to pull left or try to ground loop.
Landing the P-47 the first time proved to be a little frustrating to someone who likes to grease in their landings. I am not saying I always do, I just like to! The P-47 settles into the landing pattern just fine. Actually, it just about settles itself. I just kept adding a little elevator as I pulled back on the throttle. Here is where the first minor issue came into play. As I was reducing the throttle it cut completely out at about 20% and the plane dropped in altitude. This was not what I was hoping for so I advanced the throttle to get the prop spinning again. Unfortunately, the point at which it cut back in was bit too high so I had to cycle the motor on and off to try to get my desired landing speed. I set the P-47 down on the runway a little to fast and it bounced slightly a handful of times before settling on the runway. The taxi back to the pits was uneventful, except for the comments from the peanut gallery about my "four landings in one flight".
I have had mixed success with subsequent landings, although none have been really bad. The P-47 has a tendency to bounce on landing (pavement) if you try to finesse it in on three points. I have had slightly more success getting it down on the mains and then bleeding off speed until the tail drops. Getting a reliable slow idle from the speed controller (I now advance the throttle sub-trim before taking off) proved to be a big help in smoothing out the landings as well.
The P-47 truly shines once it is in the air. It tracks very well with limited tail waggle even in a fairly stiff breeze. The aircraft responds positively to control inputs. The recommended C.G. feels spot on. Turns are easily accomplished with out the need to add any rudder input. The P-47 does not "feel" light on the sticks but it definitely doesn't feel heavy either. During a stall test on low rate, I was amazed that the P-47 would not stall, it just mushed ahead slowly. On high rates it stalled at an incredibly slow speed and fell off to the left gently. I must say I felt very comfortable with the flight characteristics in a very short time.
When I was comfortable with the airframe, I decided to try some basic aerobatics. Some of the maneuvers I tried were not scale, but the airframe is so responsive that I wanted to try many different things. First up, a reverse half cuban eight, which was accomplished with ease. The P-47 has plenty of power to pull through the maneuver gracefully. Next, I tried a few aileron rolls. The rolls are fairly axial but the P-47 did require some down elevator while inverted to keep it from dropping in altitude. When I switched over to high rates, elevator input was not needed during the roll. After a turn around at the end of the field, I went to full throttle and tried a knife edge pass. I realize this is not an Extra, and it showed it by the way it performed the maneuver, but even though it was losing altitude quickly, I was surprised at how little roll coupling there was during the pass. I decided to slow the P-47 down a bit and try a slow roll and a slow pass at show center. The Slow roll was very graceful but it needs some corrective input to keep it level, although much less than expected. I was surprised at how slow the P-47 will fly while still remaining completely controllable with no sign of stalling.
After trying a few slower maneuvers I wanted to crank it back up again. I tried some climbing rolls, inverted flight, point rolls, snap rolls, and a few stall turns. The P-47 handled everything with ease. Sustained inverted flight is rather easy with the P-47 but it does take a fair amount of down elevator to keep it level. The point rolls are also easily accomplished. The P-47 responds crisply when input is given to stop the roll at the "points". Snap rolls are fairly precise, but it does have a slight tendency to over rotate although a bit less than expected for a warbird. Even though the knife edge didn't go too well, as expected, the rudder was surprisingly effective when performing stall turns. The turns were fairly precise with very little tail wagging after exiting the maneuver. All of the maneuvers I wrote about above were performed during my maiden flight, which should give you some indication of how extremely comfortable I was flying this airframe!
The Great Planes P-47 Thunderbolt .25/ep Sport Scale ARF is not for the true beginner, but it would be a great introduction for a seasoned modeler looking for their first warbird. It is a fairly forgiving airframe, but not too forgiving that you wouldn't have an idea about some of the basic flying characteristics of a warbird.
The Great Planes P-47 Thunderbolt .25/ep Sport Scale ARF is a superb everyday flier. The P-47 was very easy to assemble because of the high level of prefabrication. With the exception of the ESC not providing a reliable low idle at first, everything performed flawlessly for the maiden and subsequent flights. The Great Planes P-47 has proven to be one warbird you can easily fly without all the stress.
|May 04, 2009, 05:45 PM|
Very nice review. Thanks for pointing out items to look for (hatch fit and aileron exit holes) if inspecting a kit at a hobby store before purchasing. I was also glad to read that Great Planes took care of the issues you had!
I've been eying this plane for a while and it'll certainly end up in my hangar if one of the other .25 sized Warbirds I have needs to be replaced!
|May 04, 2009, 09:23 PM|
Nice! Check out the new 4 bladed adjustable pitch props at hobby lobby. They will be perfect for this size p-47. And add major realism to it.
|May 05, 2009, 01:11 AM|
Thanks for the excellent (and very thorough) review. I will be reviewing this one for R/C Sport Flyer magazine, and it helps to see what other reviewers have found. Sounds like you are really liking this plane.
I'm almost through the assembly steps, and so far I'm quite pleased with everything. It has gone together very well, with no problems anywhere (mine must be a later run kit). All put together now, except for the small details, and I gotta say it's more airplane than I had expected. It feels nice and solid, with a real model feel to it. A cheap parkflyer this is not. I put it up there with my Hyperion Yak 55 SP25e, for quality and appeal. Glad to hear it also flies well.
I never thought the Jug was much of a standout among the WWII warbirds, but this one may turn me. It sure has that Big Iron look to it-- can't wait to do low-level fly-bys with it down the runway.
|May 05, 2009, 08:08 AM|
Nice review Kevin. Really liked the "unedited" flight video, it gives a better feel of the total flight envelope of the model.
I had to laugh at the comment toward the end of your video. I can always tell when my video person's arms are getting tired of holding the camera by their comments - "are you landing yet? ... are you landing yet? ... you gotta be almost out of batteries, maybe you better land NOW".
After seeing this model of the Jug fly, I may have to change my opinion of heavy metal fighters.
|May 05, 2009, 08:29 AM|
thanks for the compliments guys...
The little Jug does fly great. you are right dgliderguy, the model is very solid but doesn't feel overbuilt. no park flier feel here.
kingsflyer, Yes that is exactly it...The video guys arm was ready to fall off. ...but i was having so much fun.
I was a little worried about including an unedited video at first, but i think it holds up well and gets the point across about my comfort level with the airframe....and how well it flies.
I now have many more flights on the airframe. my latest small issue is the rear of the hatch popping up in flight. it hasn't come off in flight yet it just pops up at the rear. i will be doubling up on the magnets for future flights.
|May 05, 2009, 03:23 PM|
New York, NY
Joined Nov 2007
Great review kevin. I really enjoyed watching the entire maiden video!
Just one thing about size of LIPO batteries for this Jag. The battery hatch wouldn't close if relatively thick batteries are used.
Zippy 3S 3300mAh (143 x 45 x 19mm) fits perfectly on my Jag, but Zippy 3S 2200mAh (100x34x27mm) wouldn't. The 3S 3200mAh battery you use measures 145 x 48 x 24mm. Any more room left for thicker battery?
|May 05, 2009, 08:29 PM|
true, you cannot fit very thick batteries under the hatch. but if you look at the pic of the bottom of my hatch in the review, you can see that there is a center former that could probably be removed to give a little more room.
|May 07, 2009, 01:28 PM|
Great review - I love this plane- it is my favorite warbird model
I replaced the stiff velcro supplied with the softer aftermarket stuff and cured the hatch poping up issue that you described.
I fly mine with an APS 4 blade 9x6 that works great and looks more scale. It produced more watts and less amp draw then the two blade 9x6
|May 09, 2009, 04:37 AM|
I popped into Todd's Models today and a customer had this very plane in the shop. She's a beaut! Great looking plane all around. I can't vouch for its air supremacy but if she flies anything like the craftsmanship she displays then it's a sure winner.
|May 13, 2009, 04:28 PM|
Here's a few progress pics of mine:
|May 13, 2009, 05:11 PM|
Mine has the recommended Rimfire motor, and yes, it is too long, by a good 3/4". I will need to move the cowl as far forward as I dare go, and at that, the prop adapter will protrude well past the cowl inlet. Yours, too?
|May 13, 2009, 07:20 PM|
the back of prop adapter on mine lines up with the front of the cowl on the right side. there is 7.5 mm of clearance from the back of the prop blade to the right side of the cowl. prop is 10x7 apc-e. it doesnt look like its too far out....
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