Dave Smith's Blog

After a stress-free build, the ParkZone Habu gave me two stress-free maiden flights. I’ll let the video do all the talking:

My new Parkzone Habu ducted fan jet arrived in the mail this week. I put it together and provide this walkthrough for the benefit of those who have not yet purchased their Habu (hint: just do it).

Stay tuned for the flight report in a couple weeks.

Parkzone Habu Walk Through from djsmith on Vimeo.

Update: Here’s the maiden flight video footage. Enjoy!

Today my friend Cliff showed me his first-person video R/C airplane:

This thing has every feature imaginable, which means it packs a lot of wires:

Here’s a video tour of all its features, which include the following:

• Auto fly-home if control is lost (uses GPS)
• Heads up video display of altitude, heading, and pitch
• RF beacon if the plane is lost
• Auto stabilization using FMA co-pilot
• Data logger providing an audible report of battery life and other stats
• VR goggles for watching the action
• Pan and tilt camera, controllable from the radio
• High-power transmitter (he’s flown a mile away on FPV)

My brain’s been a stewing about 2010, and I just gotta let it all out. If I’m even half right, 2010 will be awesome.

1. Hulu in the Living Room

In 2010, Hulu will partner with a company like Western Digital or Popcorn Hour to release a tiny box that connects to your HDTV to watch TV shows and movies, streamed from Hulu’s servers. The box will cost less than $100, and have no monthly subscription, because its development will be subsidized by Hulu’s ad revenues. If it’s not released in 2010, it will at least be announced.

2. Cable Networks Become Record Labels

Just like iTunes changed the music industry, online media and broadband Internet access will start to change the TV industry. It remains to be seen who will be the big player (my money’s on Hulu), but one thing is for sure: Americans will have a choice when it comes to buying subscription TV services. The trend will begin in 2010, allowing consumers to get on-demand TV content for free, and will finish some time in the future with cable companies either totally transforming into something like modern record labels, or going out of business.

3. HDTV Sales Will Boom

HDTV’s have gotten so inexpensive that nearly every American household will have one by the end of 2010. This will be driven by the fact that online media will be so easily accessible that most people won’t need to buy cable, so they can easily justify the cost of a new $500 TV.

4. Qt’s Best Year

Companies who develop desktop application software that needs to run on Mac and Windows will simply have no other choice for their developers than Qt. That trend will strengthen in 2010 to the point that it’s a no-brainer decision over platform-specific choices like .NET, Cocoa, and others. Qt has matured so much over the last 5 years that its toe-hold in this market will grow to a full Nelson in 2010.

5. Model Aviation Takes Off

Model airplanes have gotten very popular and accessible. Manufacturers have pushed prices down so low that anyone can afford to get into the hobby. Batteries, R/C electronics, and planes have gotten cheaper, and planes have gotten easier to fly for the novice pilot. The entry-level model airplane market will take off in 2010.

Your Turn

Do you agree with my predictions, or am I totally off?

Have any predictions of your own?

I finally took my newly built Stryker to the slope for some unpowered slope gliding at Ensign peak in Salt Lake City, Utah. I built the Stryker with these parts:

• Stryker Fuselage from ParkZone
• A tiny 2-cell LiPo battery
• Two cheap servos
• A cheap voltage converter

I did not put a motor on the Stryker and used a tiny battery. It slopes beautifully in 15-20mph wind. In fact, I had to add some weight to get better penetration.

I highly recommend the Stryker for slope flying.

To celebrate Independence Day, I flew my T-28 with red, white, and blue streamers around the park.

If you want to give your ParkZone T-28 Trojan unlimited vertical flight for under $30, today is your lucky day. Just head over to hobbycity.com, and pick up one of these Turnigy 35-36C motors.

Here’s what you’ll need to do the upgrade:

1. The new motor (duh)
2. A Phillips-head screwdriver
3. An everyday drill and an ordinary drill bit
   (not sure of the drill bit size — you’ll figure it out)
4. A new prop (I use an APC 10×3.8). The stock prop’s shaft is too wide for this motor’s prop adapter

You may be asking:

• Do I need a soldering iron? No.
• Do I need to cut some wood or aluminum for a firewall? No.

Here’s what you do:

1. Unscrew the three screws that secure the cowling to the nose of the plane
2. Unscrew the four screws that hold the plastic motor mount to the firewall
3. Disconnect the three motor wires (red, yellow, and black)
4. Unscrew the motor from the motor mount
5. Use the cross mount thing that came with the motor to pencil in the 4 new holes you’ll be drilling
6. Drill the holes (be sure to use a drill bit that is the same size as the old holes
7. Screw the motor on to the mount, connect the wires, and put the whole thing back on the plane
8. Hold the plane straight up, power it up to full throttle, and release
9. Watch it fly straight up to the clouds like a friggin’ rocket

Here are some photos of my (not so) handiwork:

This is what it looks like when it’s done. The motor isn’t quite as long as the stock motor, so I tossed a nut on the shaft before I put the propeller on. Without that nut, the prop would be rubbing on the cowling.

Here’s the motor bolted to the stock motor mount. I was in the process of screwing in the 4 mounting screws when I took this.

Here’s where I drilled the 4 new holes for the new motor (circled in blue). The new motor has two holes that are perfectly spaced to line up with the stock motor mount, but the other two holes are actually closer to each other, so you have to drill. I opted to drill 4 new holes, but you may get away with using just two of the stock holes, or even drilling only 2 new holes. I wasn’t quite willing to trust that, and after seeing just how much torque this motor provides, I’m glad I didn’t.

You may also notice in the photo above that this motor has a really weird prop adapter. Rather than tightening on to the shaft, it actually screws onto the bell of the motor. Notice that the motor has a shaft that extends out the aft side of the motor (if you wanted to mount it in reverse). I’ve never seen that in a motor before, but I like it. It seems much sturdier with 4 screws on the bell than a single set screw or “clamp” style prop adapter fastened to the shaft.

The Results

I took it out to the flying field today and did my usual hand launch. Except this time I only launched it using half throttle. It flew out perfectly. After a couple seconds, I punched it up to full throttle and aimed the nose at the clouds. It flew perfectly vertical for a good 5 seconds, showing no signs of slowing down. It was awesome. I was flying huge loops, square loops, vertical rolling ascents. It was great.

One problem is that the plastic motor mount causes a lot of vibration at the higher end. Oddly, the vibrating happens at about 75% throttle, but then goes away at 100% throttle. I am looking into using an aluminum mount instead. Lots of people have reported that a sturdier mount fixes the vibration problem. Don’t underestimate the vibration problem — it caused my plastic motor mount to break with a big 11″ Master Airscrew prop.

The Electronics

I used the stock speed controller (ESC), but I also have a ParkBEC because I don’t trust the stock ESC’s integrated BEC at all, having heard lots of horror stories about it. The stock ESC showed no sign of overheating, though it was about 45 degrees F outside. The motor stayed cool too.

I used a new Zippy 2200mah battery from hobbycity.com. It did great too. No signs of overheating. It came down just barely perceptibly warm to the touch. Within seconds, it had cooled to room temperature. This was the first flight of the new Zippy battery.

My Watt’s Up tells me that the 10×3.8 prop makes this motor pull exactly 30 amps. That’s a lot of amps for this ESC, so I also bought a SuperSimple 50A ESC from hobbycity.com, which I have not installed yet. I may wait to see how the stock ESC performs for a while, because I just don’t want to solder all that crap again (including the ParkBEC).

Bottom Line

This motor is awesome. I plan to use the T-28 as an Aerotow plane soon, so this motor will give me exactly the torque I need. The plane is still quite a slow flyer compared to my Stryker, but even though the T-28′s top speed is lower, it has better vertical.

A couple weeks ago I sent my Spektrum AR6000 receiver to Horizon Hobby’s service department because it was losing bind on the ground (especially in cold weather). Oddly, I could never reproduce the problem on the bench. It only happened at the flying field, and only on hand launches. Very weird. I was nervous that I would destroy my plane if it ever lost bind in the air, so I finally decided to send it in for service. I didn’t have much hope that Horizon would be able to see the problem since I could never make it happen on the bench, but they graciously took my word for it and replaced it free of charge. All I paid was the $5 to ship the receiver to them, and they replaced it and shipped the new one back to me free of charge. This was after they failed to reproduce the problem after 15 attempts. Way to go Horizon! I’m now a loyal customer for life.

P.S. Larry Weddle did the service, and decided to send me the new AR6000. Good work Larry!

Finally a successful maiden flight! Here are some post-maiden photos of my T-28 Trojan from ParkZone.

This tiny dots to the right and left of the cockpit mark the Parkzone recommended center-of-gravity (2.5″ back from leading edge, measured 1″ out from the fuselage). I moved it forward by about 0.5″ and it flew better.

On my first flight, the elevator was trimmed way too far up, leading to a near-death experience. I landed it, fixed the elevator sub-trim, moved the CG forward 0.5″ and it flew beautifully. In your pre-flight checklist, be sure to verify that the elevator is totally level (co-planer, to use geometry terms) with the horizontal stabilizer forward of it.

This shows my battery compartment and where I positioned my 2200mah battery pack to balance properly. I used velcro to secure the battery to the floor of the battery compartment.

To fit my battery as far aft as I did, I needed to remove some foam from the bottom of the cockpit:

This is where I mounted the ParkBEC as an insurance policy against the included speed controller’s crappy BEC. Since this is a switching BEC, it produces a lot of electromagnetic interference, so you want to put it as far away as possible from your receiver and antennae. Even though it creates lots of EMI, it creates virtually no heat, since it is very efficient at stepping voltages down.

My last landing was gorgeous. I even held a 10 degree flare during final approach that really greased it in for a smooth touch down and roll out. However, the left wing must have caught something hard (a particularly hardy blade of grass perhaps) that pulled the left landing gear right off. Nothing a bit of epoxy won’t fix:

What a great flyer. This is truly a bank-and-yank plane and is very easy to fly. The motor provides adequate lift to climb out at 45 degrees all the while showing no sign of slowing. The vertical is limited to about 30 or 40 feet from flat flight, and the roll rate is very very slow and non-axial. It flies just slightly better than a brushless HobbyZone Super Cub with ailerons. I think I need to increase my aileron servo travel to get some really good rolls. I will probably also mix in some differential to make the rolls more axial and pattern-like.

Oh, and I’m fairly certain that in a few months, it’ll be time to upgrade the motor for insane speed and unlimited vertical.

Well, I upgraded my L-39 jet’s motor and re-maidened it. I don’t want to give away the ending but it wasn’t pretty. The new motor was fantastic. It bolted in with no modifications to the plane, and provided lots of thrust over the stock motor. It was great.

The added thrust helped control the plane. Without it, I would have been toast out of the gates (like last time). The take off was uneventful other than the 90 degree right roll on launch and the first turn which almost crash landed the plane right into the adjacent road. Yikes! Here’s the video:

Everything was going okay, but it was extremely twitchy and stall happy. I think it’s too heavy, cause I was fighting to keep it aloft the whole time. I held my own for a few minutes, and then the low-voltage cut off kicked in. The motor must have been pulling more juice than I realized. I was up wind, which was a problem because the wind was blowing at about 10-15mph. Nevertheless, I managed to bring it in for a nice soft landing. Well, “soft” is relative. The plane touched down at the same spot where the only obstacle in the whole park was sitting: a sideways metal pole. Oops. Here’s the video and crash site photo:

You can’t tell very well from the pic but both the wing and horizontal stabilizer are bent, because they went under the poll while the rest of the plane went over it. Not pretty.

Oh well. Live and learn. My battery was badly puffed (due to the low voltage and high amp draw I’m sure), but it subsided back to normal. Not sure if I trust it for another flight yet, but I will definitely be keeping it in an ammo box and carefully monitoring its voltage before I use it again.

Thanks Cliff for filming!