F/A-18 Super Hornet

F/A-18 Super Hornet 

Build with RCPowers’ plans, fanfold foam, and 4 years of aging. 

The story behind the plane.

A few years ago, sometime in 2011, when my interest was re-engaging in RC models, I watched Dave Powers flying his park flyer jets and I was hooked. I purchased his package, got my plans and then discovered the cost of Depron foam. Being the cheapskate that I am, I couldn’t bring myself to buy Depron. Seems silly now, after spending a hundreds of dollars on a transmitter, equipment, motors, ESCs, servos, etc. etc. Instead of buying Depron, I spent a considerable amount of time investigating alternative foam materials and I didn’t come up with any perfect solutions. However, through the searches I discovered that a few people were using the fan-fold insulating foam as a plane-building material. I priced it out and although the initial investment seemed high, it didn’t seem too expensive per sheet, so I purchased a bale. First, I will point out that I wanted perfect sheets (no waste), so I had to go through quite a few bales in the hardware store in order to find one that wasn’t mashed, crumpled or damaged. Even then, the outside pieces were damaged from the bands that held the bale together. I figured I could use the damaged pieces for smaller parts. The fanfold foam was not designed to have a consistent thickness, so it is kind of “wavey” on one side. Nevertheless, it proved to be pretty good material, as you will see. I liked the property of it feeling strong and springy. Sure, if you bend it too far it does break, but you have to put a pretty tight fold into it before it breaks. After flying this F/A-18, I would now rank the fan fold foam pretty high on the scale of durability. But, just like all other foams I have tried, it lacks the rigidity to support large single sheet surfaces, so it has to be reinforced with wood, fiberglass or my recommendation - carbon fiber tubes.

Building the F-22 Raptor

When I began building planes, just like a lot of folks, I just had to start with the coolest plane - the F-22 Raptor. I measured the thickness of the fanfold foam and compared it to the dimensions of the Depron that was specified in the plans and discovered that the fanfold foam was a little more than twice as thick. Well, at the time I didn’t think that would be a big deal - foam is light! I was getting really excited to see my first scratch built plane come together. It looked so cool, even in pink! I added all the extras too, KF airfoils (Kline–Fogleman), rudders, ailerons and elevators (you know, the works).

Raptor’s First Flight

Without simulator practice… just jump right in because, how hard can it be, right? So I charged the battery and went down to a field behind a nearby middle school. Spin up the motor at half throttle and toss the plane into the air - it went about 10 feet. The good news was there was no damage. I figured it just needed more power.

The second throw was with the throttle at full tilt! That was the trick. Look I’m flying! Sure it flew, but barely, a wobbly high alpha trajectory heading straight for the baseball backstop fence. As it picked up speed it started to level off. Turn! No, not that hard... After making it through the turn I wanted to get more than 5 feet off the deck, so I pulled up. The plane just went crazy on its own with a 30 foot loop and into the ground full speed. Crunch! Darn it - flying is not as easy as it looked. Certainly not as easy as Dave Powers made it look!

The nose was completely mashed. The post crash investigation showed that I had not properly secured the servo wires.

During the last seconds of controlled flight, the servo wires running to the elevators and ailerons got tangled up in the propeller. What is really funny is that I spent probably close to an hour searching in the grass for the ends of the servo wires that got clipped off. Yes, I finally found them, about 50 feet from the crash site. They got flung a long way. Lesson - properly secure the servo wires out of the propeller’s reach. I learned a valuable lesson with the wires, but more importantly I learned that original specifications of the plan count. Don’t go thinking that a plane that weighs more than twice the specified weight will perform. This version of the F-22 was powered with a 2200 mAh 3S 40C battery, 30A ESC and SuperSonic - 2212-06 V2 from Grayson Hobbies (as specified by RC Powers for the 1x sized F-22) with a 6x4 prop. Lesson #2 learned - twice the plane requires twice the motor - build to the plan unless you really know what you are doing. Every bit of foam adds more weight.

Now we come to this beautiful plane, the F/A-18 Super Hornet. I built the F/A-18 at the same time as the F-22. To make it really cool, I even got an airbrush and painted it to match the U.S. Navy Flight Demonstration Squadron, the Blue Angels. But after the F-22 fiasco, I didn’t want to fly the F/A-18, I mean, crash it too. So it just hung out in my basement, unused, almost forgotten, and taking up space.

On one evening a couple of years ago, I participated in a talent night at my church in which I displayed the many models that I had built, mostly Flite Test models and the F/A-18. The kids were really liking the big, blue-painted, cool F/A-18 Super Hornet. At the close of the evening I had some of the boys carry the planes out to my truck, the F/A-18 was the last to be loaded. I asked if they wanted to see it fly and of course they all did. It didn’t have any electronics, wasn’t balanced, had floppy control surfaces, but since I thought it would never fly, what the heck. So I gave it a good throw and it almost glided to a nice landing in the snow. I was going to trash it, but after I saw it fall with style so nicely, I decided to take it home. It sat there for another year, not forgotten but just not equipped, until a few months ago. I wanted more space in my hobby area for other planes so again I decided to toss it out. But, I couldn’t just break up such a pretty plane and throw it away. Hey, I know. Why don’t I let the impact of a maiden flight with the ground do the breaking for me?

So, I glued on some servos, mounted the beefiest motor I had, the Super Mega Jet V2 from Grayson. According to Grayson and Dave Powers, this is the motor to use if you wanted a “faster” RC Powers model. Here are the specifications that Grayson Hobby provided with the motor:

This motor is specified to handle 55A for 60 seconds max. You should notice that both of these setups pull less than the maximum current rating for the motor. In the motor stats section, Grayson recommended using a 6x5.5 prop (which should draw more  amps) and sells the motor combo with a 50A ESC. So, what did I do? Yup, supersized it… put on a 7x6 prop, dropped in a Turnigy Plush 40A ESC, add power and measured the current to make sure I wasn’t going to burn out the motor or ESC. A short burst at full throttle drew 50A, which is below the 55A/60s max for the motor but above the 40A ESC. So, I changed out the ESC for a Plush 60A. There, that should do.

Balance the plane.

With the powertrain added, I made sure the CG was spot on. My experiences have taught me that this is by far the most important element to get right if you want a plane to fly.

The day of the maiden.

So, the perfect day came - no wind. Take a look at this maiden flight. I had to dial in a little trim (it really wanted to roll right and climb at first) but after trimming, it was like flying a dream!

My CapCam battery stopped about halfway through the maiden flight, so I threw in the video that my friend, Chris, shot it using my handycam showing a slow pass, a few rolls and the landing. Since then I’ve flown this F/A-18 dozens of times. The rudders were really touchy at 100%, so I decreased the rate, increased the rates of the elevators and left the ailerons alone.

More Flights

Flight Characteristics

I am very pleased (stunned and surprised) with how well this F/A-18 Super Hornet flies. It is a little bit underpowered for the acrobatic enthusiast, as I suspected from the start, but it flies pretty good at 60% - 70% throttle. After a 5 to 7 minute flight, the motor is very hot to the touch and the ESC is nice and cool. I’m worried that I’m pushing the motor a bit too hard. I don’t have a way to measure the temperature.. It flies so well that I am strongly considering beefing up the powertrain (just a little) to preserve the motor. But there is little problem, the prop hole is only big enough for a 7 inch prop. So rather than increasing the prop size, I guess I’ll just have to spin it faster. The motor is rated at 2200 kv. Hmmm… going to have to think about that. Maybe change the size of the battery from 3S to a 4S battery?

The rudders are very responsive, surprisingly so. If I were building this again, I would make one rudder static or leave both static. A little rudder movement really causes the plane to skid. If you are into high alpha slow flight, then you will probably want and need the yaw control, otherwise, I don’t see much use for it. Both the ailerons and elevators give good clean performance. Snappy rolls and quick reaction. After dialing it in, I set the high, medium and low rates for the elevator at 100%, 90% and 80% and for the ailerons at 60%, 40% and 20%. I like flying at the medium rate setting for the majority of the time.

In the beginning there was a plane that I almost threw away. Now it has become one of my most favorite to fly. I guess it is true, you fall in love with the planes that fly the best. This one is stable, tracks like an arrow and is really tough and spongy.

The Final Touch

Video Playlist

F/A-18 Hornet Parts and Statistics
Motor - GH Super Mega Jet V2 2200 kv (Grayson Hobbies)
Propeller - APC 7x6 (Radical RC)
ESC - Turnigy Plush 60A (Hobbyking)
Servos - x5 metal gear 9 g (Hobbyking) 2-Aileron, 2-Elevator, 1-Rudder with a wire connector
Receiver - FrSky D8R-XP 2.4Ghz
Transmitter - FrSky Taranis Plus, mixed flaperons, dual rates and exponential input.
Fanfold Foam, Gorilla glue (HomeDepot)
Carbon Fiber tubes and Epoxy (Radical RC)

Weight (without battery), 1 lb 11 oz (766 g).
Battery - 2200 mAh 3S 40C, 7 oz (196 g)
Flight weight - 2 lb 2 oz (962 g).
Wingspan - 36 ½ inches (93 cm).

Plans from RC Power. Note: the plans have a copy right (and were discontinued) so I will not share. Nonetheless, the plans for a newer version are available here.

HilldaFlyer September 2015