Written by Don Slusarczyk Jets As seen in the SPRING 2020 issue of Park Pilot
>> When a pilot wants to transition from conventional RC airplanes to EDF (electric ducted fan)-powered aircraft, I often recommend a pusher-style jet first before buying an EDF. This is because a pusher jet still has the familiarity of a park flyer, mixed with some characteristics found in an EDF. The main issue I see with beginners flying EDF aircraft is learning that they need to be thrown hard enough to have enough airflow over the flying surfaces right after launch for effective control. A pusher jet, similar to an EDF jet, has no propeller blast over the control surfaces, so this is something a newcomer to EDFs needs to familiarize himself or herself with. At a swap shop, I came across the latest version of the Lazer pusher jet that is sold by Dan Greathouse. Some of you might know Dan from his previous RC venture, Lazertoyz, and perhaps you have seen his products at the Toledo Show: R/C Model Expo (toledoshow.com) that is typically held in April each year at the SeaGate Convention Centre in Toledo, Ohio.
The updated EZ Lazer sits next to the original version of the Lazer.
Assembly starts by gluing the wing components together.
Dan is back in the RC business with a new company, EZ Build RC (ezbuildrc.com), and this is an updated version of his popular Lazer design, called the EZ Lazer. This lightweight park flyer is great for getting used to pusher-style jets. A variety of motors can be used to increase performance as your flying skills sharpen.
Left: The airframe is done after a few minutes using the hot-melt glue gun. Above: All of the required electronics can be purchased directly from EZ Build RC.
The EZ Lazer comes with prepainted, laser-cut foam parts. The control surfaces are pre-hinged, and the carbon-fiber wing spar is preinstalled. The airframe has a low parts count and can be built in a short period of time with conventional foam glues or hot-melt glue. The hot-melt glue was recommended in the assembly manual, so that is what I chose for most of the build. Make sure to use low-temperature hot-melt glue because some of the high-temperature glues can melt the foam. The airplane’s assembly is straightforward. The main wing pieces are glued together, followed by the upper and lower profile fuselage section pieces. The vertical fins fit into precut slots in the wing and are held in place with hot-melt glue.
Left: The airframe is done after a few minutes using the hot-melt glue gun. Above: All of the required electronics can be purchased directly from EZ Build RC.
A guide prevents the wire pushrod from bowing in flight.
On the underside of the fuselage, near the nose, two foam doublers are glued to each side of the fuselage profile for added strength and to create a slot to hold the flight battery. It also serves as a great place to hold the model when you are launching. The servos are adhered with clear tape then hot-melt glue is applied around the servo case to secure them. The only place I did not use hot-melt glue was on the control horns. I installed those with some 5-minute epoxy. A 1,700 Kv motor is recommended and it requires a 12-amp ESC when used with an 8 x 4 direct-drive propeller. A 3S 650 mAh LiPo battery is also recommended. All of these items can be purchased from the EZ Build RC website if you want to buy a complete package. The 1,700 Kv motor comes with a metal motor mount that is screwed to the included plywood motor mount. Hot-melt glue was used to attach the plywood mount to the back of the airframe. With only two servos, the ESC and radio installations take just a few minutes. With the help of some zip ties and a few pieces of clear tape, the electronics fit nicely into the tunnel on the underbelly of the airplane. Because this is a flying wing, you will need elevon or delta mixing activated on your radio. Set the aileron and elevator throws to approximately 1/2 inch up and down for your initial flights. Check the propeller rotation and verify that the propeller is installed in the correct direction. Putting a propeller on backward is easy to do on a pusher. The final check before the maiden fight is the CG (center of gravity) location. With the recommended electronics and LiPo battery, the CG on the Lazer was approximately .7 inch in front of the servo slots. I added a few clicks of up-elevon trim (roughly 1/8 inch up) then I was ready for the maiden. With approximately 2/3 throttle, the aircraft should be launched straight ahead with a firm throw, with the pilot taking care not to roll his or her wrist left or right. The Lazer should start to climb out. Mine only required a few clicks of trim for it to fly how I liked. With this power setup, I was able to fly in a football field-size area at my local park. The aircraft’s light weight and motor/propeller combination provided plenty of power for climbing, looping, and rolls. It also flew nicely at half throttle, doing lazy laps around the park. If you are looking for an easy way to get into park flyer jet pusher aircraft, the EZ Lazer just might be the airplane for you.
