Hangar 9 Pulse 125 XT
After flying my Hobbistar trainer for all of 2011 I was ready for something new. After asking around I decided to go for a low-winged sport plane that could be powered by the DLE-20cc gas engine. The Pulse 125 was a natural choice.
I bought the Almost Ready to Fly (ARF) airframe in September of 2011 and began to accumulate the components I would need for the assembly. Later that month, and after a lot of time online spent chatting with Pulse 125 owners, I got started.
The assembly turned into a build*. As things progressed it became evident to me that some areas of the stock configuration could be improved, such as:
- Elevator servos: Two external vs one internal
- Rudder linkage: Pull-pull vs push rod
- Canopy: Removable vs glued
Before I knew it, the ten hours' assembly time quoted in the manual had turned into more than a hundred. Of course, a lot of custom work was involved in making changes to the design and fixing mistakes made as I went along.
*Typically, putting together an ARF is an "assembly" while putting together a kit is a "build". I spent so much time on the Pulse that I'm comfortable using the latter term.
I maidened the Pulse in 2012 on a windy day in April. Right away I noticed that the stock gear, which is swept back considerably, gave the plane a tendency to nose over while taxiing. So much so that holding up elevator when taxiing downwind would cause the tail to rise. My first attempt to solve this problem was a riser block for the landing gear. That didn't help much, so I ordered some aftermarket gear. Problem solved for the 2012 season... but I prefer the appearance of the stock gear so for the 2013 flying season I've taken a suggestion I found online and moved the stock gear forward on the fuselage.
The maiden flight went pretty well considering the face that I was terrified. Luckily the CFI was beside me reminding me to breathe, and another good buddy was there to help with getting the plane trimmed. In retrospect it was probably too windy for a maiden that day, but everything worked out in the end.
Early in the 2012 season, our club formed an aerobatic interest group (AIG). Headed by Gary, our affable and easygoing events planner, the aim of the AIG is to promote precision aerobatics with the aim of learning IMAC sequences and possibly competing in International Model Aeronautics Club (IMAC) events. Gary, ever patient, coached me and other RC pilots through practice every week and early one Saturday in July I showed up for my first competition, having flown the entire sequence of ten maneuvers for the first time just a few days before. It was a lot of fun - and I got to write an article for the RC Scale Aerobatics column in the MAAC magazine - Model Aviation Canada.
The DLE 20 gas engine I put in this plane did not originally run as reliably or pull as hard as I had hoped. I've made a number of modifications to the engine that have improved the performance: Smoother idle, better transition and more power - see the links in the Modifications section below. The engine still will not draw fuel by hand flipping for the first start of the day, so the next step is to solder the choke hole plate closed.
|Flight time:||7h 38m|
|Wingspan:||1930 mm (76")|
|Length:||1590 mm (62.5")|
|Weight:||5.2 kg (11.5 lbs)|
|Powerplant:||DLE-20 20cc two-stroke gas|
|Receiver battery:||5-cell 6.0V 2700 mAH NiMH|
|Ignition battery:||4-cell sub-C 4.8V 4200 mAH NiMH|
|Ignition kill:||Smart-Fly fibre optic|
|Aileron servos:||Hitec HS-645MG x 2|
|Elevator servos:||Hitec HS-345BB x 2|
|Throttle servo:||Hitec HS-645MG|
|Rudder servo:||Hitec HS-645MG|