E-flite PT-17 1.1m BNF


Review by Terry Dunn This Navy trainer is a joy to fly Product review As seen in the March 2018 issue of Model Aviation

Review Video



Specifications

Type: Semiscale foam electric Wingspan: 44.6 inches Wing area: 643 square inches Length: 33.5 inches Radio: Spektrum DX8 2.4 GHz transmitter; Spektrum AR636A receiver (included); four Spektrum A330 9-gram servos (included) Components needed to complete: Minimum six-channel DSM2/DSMX transmitter; 3S 2,200 mAh 30C LiPo battery Flying area: Club field Price: $229.99 BNF; $199.99 PNP (does not include receiver) Power system: E-flite BL 15 850 Kv brushless motor (included); E-flite 40-amp ESC (included); 11 x 7 propeller (included); E-flite 3S 2,200 mAh 30C LiPo battery Power output: 26.6 amps; 292 watts; 88 watts per pound Flying weight: 53.2 ounces Flight time: 8-plus minutes Wing loading: 11.9 ounces per square foot

Pluses

• Excellent scale profile and details. • Easy, tool-free wing removal. • Smooth and aerobatic flight performance.

Minuses

• Stiff landing gear. • Manual overlooks some elements of wing assembly.

Product Review

The Boeing-Stearman PT-17 is a well-known airplane that goes by many names. Maybe you call it a Model 75, N2S, or Kaydet. Most people refer to this aviation icon simply as the Stearman. The full-scale airplane’s impressive list of monikers reflects its longevity and the diverse roles that it has had since the 1930s. Likewise, this classic biplane has long been a favorite subject of RC modelers. E-flite’s newest Stearman rendition is constructed primarily of molded foam. It is available as a Plug-N-Play (PNP) model or the Bind-N-Fly (BNF) basic package reviewed here. Both versions include factory-built airframe components with preinstalled servos and a brushless power system. You must add a three-cell 2,200 mAh LiPo battery equipped with an EC3 power connector. The primary difference between the two versions is that the PNP unit does not include a receiver. A Spektrum AR636A receiver comes preinstalled in the BNF model. You’ll need to provide a DSM2/DSMX-compatible six-plus-channel transmitter. The airframe components come prefinished in a U.S. Navy color scheme. Technically, that would make this an N2S instead of a PT-17, but let’s not get too technical. The important thing here is that the paint on the model looks great. The only fault I could find is that some hinge areas of the rudder escaped the factory’s airbrush. I touched up the bare spots with latex house paint. Valspar’s sunset glow is a nearly perfect color match and can often be purchased in a sample size for a few dollars. Even the insignia and other decals are factory applied. Mine are positioned correctly and have no wrinkles or bubbles. I especially like that the decals match the matte finish of the paint. A painted pilot bust in the rear cockpit adds to the model’s scale realism. You will also find a detailed replica of a Continental R-670 seven-cylinder radial engine shrouding the BL 15 brushless motor. Landing gear strut covers and other detail-enhancing pieces are present as well. To me, the only thing that looks out of place is the squared-off shape of the propeller tips. The overall scale appearance is quite convincing for a factory-built model.

Assembling the PT-17

Set aside an hour or two to get the PT-17 unboxed and ready for flight. All of the hard work is already done for you. Only a few basic assembly steps remain.
E-flite’s PT-17 is a foam model that comes mostly preassembled and factory finished in a U.S. Navy paint scheme. Little is required to get it airworthy.

Construction begins by bolting on the landing gear. It requires some gentle bending to get the plastic strut covers over their mating bulges on the fuselage. The tires are adorned with the classic diamond tread pattern. They are also exceptionally stiff. Functional spring-loaded oleo struts help offset the tires’ hardness. The oleos on my model, however, do not work smoothly. The end result is landing gear that looks great, but is more rigid than I would like. A handy feature of this model is that both wings can easily be installed or removed without tools. The top wing is held in place with four long pins that mate the cabanes and wing struts with plastic mounts embedded in the wing’s foam structure. The system is easy to use and securely holds the wing. The bottom wing attaches to the fuselage with a tab in front and plastic studs in the rear. Metal clips on the wing rotate to lock the studs in place. The manual overlooks the installation of these clips. It also fails to mention that the studs are threaded and must be accurately positioned to work correctly. I backed out the studs until they protruded through the wing. I then screwed the studs back down until the holes for inserting the clips were flush with the wing surface.
Both wings can be installed or removed without tools. Small clips retain the bottom wing (L), while long pins bind the top wing to the struts (R).

I initially had trouble getting the plastic studs to fit through their respective holes in the wing. This was because of paint on the walls of the hole. I cleaned the paint away by lightly twisting a 5mm drill bit in each hole. I also scraped away paint that was preventing the wing struts from snapping into the bottom wing. I linked the AR636A receiver to my Spektrum DX8 transmitter. This receiver has built-in AS3X stabilization. The purpose of AS3X is to compensate for the effects of wind gusts and other elements that could upset your model’s flight path. It does not fly the airplane for you; it merely helps make your flights look smoother. The AR636A also has SAFE Select. When engaged, this feature limits the bank and pitch angles that you can execute. SAFE Select will also return the model to level flight if you release the controls. Think of it as a partial safety net for pilots who are unsure of their skills. It is possible to configure the receiver in two ways. One method disables SAFE Select completely. I suspect that most experienced pilots will choose this option. The other method allows you to enable or disable SAFE Select stabilization with a switch on your transmitter. I initially configured the control throws per the manual. After a few flights, I decided that I wanted more rudder authority. Moving the pushrod clevis to the innermost hole on the rudder control horn provided the additional throw I was looking for, but also created interference with the elevator joints. I resolved this situation by using a sanding drum to slightly expand and reshape the joiner cutout in the rudder. The plastic dummy motor is a great accent piece on this model. I decided to make it pop a little more. First, I removed the plastic motor for better access. Referencing photos of the R-670 that I found online, I used plastic model paints to add a few color accents. I also emulated chipped paint on the cylinders with a silver Sharpie marker.
The dummy radial engine looks nice in stock form (L), but the author felt compelled to add accents with plastic model paints (R).

The cockpit area features a large magnetically secured hatch that covers the radio bay. A tab of clear tape protrudes behind the rear cockpit to act as a grip for hatch removal and installation. It works great, but I think it is a little unsightly. I eventually figured out that the pilot figure can be used for the same function. It is a sturdy part and is secured to the hatch with a plywood backing plate. I subsequently removed the tape and have had no problems. My PT-17 is powered with an E-flite three-cell 2,200 mAh LiPo battery. The battery mounts to a plastic tray, which is then inserted in rails in the fuselage. The angle of the rails prevents the battery from reaching all the way to the back of the firewall. I needed the battery in that position to attain the correct center of gravity without adding ballast in the nose. I placed a scrap of 5/8-inch thick foam between the battery and the tray. This foam is attached to the tray with double-sided tape. The spacing afforded by the foam allows the battery to be positioned against the firewall. Self-adhesive hook-and-loop tape on the battery engages with the hook-and-loop straps on the tray to help prevent the battery from shifting.
Adding a spacer made of 5/8-inch thick foam allowed the author to position the battery against the firewall. Note the hook-and-loop tape on the battery that engages the strap.

My completed model weighs 53.2 ounces, which is 2 ounces more than specified. Even so, the wing loading and power loading figures suggested that the Stearman would be a great flying model. That turned out to be true!

Flying the PT-17

The PT-17 has a steerable tail wheel, so taxiing is no problem. It is possible to jam the throttle and get the airplane off the ground quickly. I find that slower, half-throttle takeoffs are more pleasing to watch. Little rudder correction is required to keep the model tracking straight down the runway. I am impressed by this Stearman’s smooth flying qualities. The model has a mild-mannered demeanor, even if you get heavy-handed on the sticks. That is not to say that it isn’t aerobatic. Much like the full-scale PT-17, this downsized biplane has quite a few tricks up its sleeve.
The PT-17’s radio bay is clean and uncluttered. Rails for the removable battery tray are located above the ESC.

Loops and rolls are easy and fun. The airplane will also willingly sustain inverted flight. I initially thought that the Stearman’s rudder authority was too light. Things are better since I increased the rudder throw. Hammerheads and wingovers look nice. The airplane won’t quite fly knife-edge with the wings vertical. It will, however, lock into a beautiful, deep sideslip. Power is adequate for the types of maneuvers one would expect from a Stearman. A preparatory dive will help extend your vertical lines slightly higher. Full-throttle is not fast, but it’s certainly above scale speeds. The airplane looks more convincing in the sky when you pull the power back and slow things down. Engaging SAFE Select gives this model a different feel. The pitch and bank limits rule out any aerobatics. Large control inputs result in docile turns. I’m sure that less experienced pilots will appreciate this behavior. Unlike the full-scale PT-17/N2S, I wouldn’t use this model as a primary trainer. I think it could be a practical second or third model with SAFE Select engaged. Experienced pilots using SAFE Select might find themselves using a lot of body English to coax their tranquilized Stearmans around the pattern. Most of my biplane models slow down and descend rather quickly when I pull the power back. This PT-17 is different. It retains energy surprisingly well. Sometimes I cut the power during final approach and float in for a landing. Other times, I maintain a few clicks of throttle all the way until touchdown.
The PT-17 has a smooth flight performance. Similar to its full-scale namesake, it is capable of basic aerobatics.

The manual suggests setting a flight timer for 5 minutes. That’s conservative, but probably a good place to start. My flights usually consist of a mixture of laid-back cruising and full-power aerobatics. I find that I can easily get 8 minutes of flight with some reserve.

Final Approach

If you’ve been itching for an RC model of the Stearman, E-flite’s new release is about as accurate and detailed as you can ask for in an ARF. Many will be happy with its looks right out of the box. Others will find ample opportunity to implement their own personal touches and tweaks. Either way, I think that everyone will appreciate the PT-17’s gentle flying qualities. —Terry Dunn terrydunn74@gmail.com

Manufacturer/Distributor:

Horizon Hobby (800) 338-4639 www.horizonhobby.com E-flite (800) 338-4639 www.e-flite-rc.com

Sources:

Spektrum (800) 338-4639 www.spektrumrc.com


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8 comments

Great review and very informative, Like the mods he did with the Pt-17 and especially the battery mod. That is a very good idea and would work on a couple other planes I have.

Great video and commentary. Hooray for Safe Select! The plumber Pilots Friend!

What camera and mounting system did you use for the flying video shots?

I used a pair of RunCam2 action cameras mounted in several different ways. You can see a few of the techniques I use in the July 2017 issue...and here: http://www.modelaviation.com/mounting-action-cameras

Good job, Terry!

Terry, very good review. I had trouble with the u-tube video, but made it thru it.A lot of good info. All the other reviews on the PT-17 say the same thing, the plane is a great flyer but tail heavy. I'll give your idea a try with the battery. I experimented with the weight factor and decided that the weight of a D cell battery is about what is needed to keep it from being tail heavy, but that is a lot of weight. Here is hoping you idea will work...tks for that info... Good flying

This aircraft is not tail heavy, or even close. It does have a good amount of positive incidence in the wings. You can test this by flying it inverted. I mixed about 5% down elevator to throttle and it flys perfectly. Straight and level at all speeds. I use a 2200mah pack in the stock location. (Not slid forward) This aircraft is a joy to fly!

great video but have been looking to buy this kit but cannot find anywhere

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