ELECTRICS - 2012/06
Signal Quality Indicators on the DX7s
On the subject of safety, there is a screen on the DX7s that can be slightly confusing. It shows letters and a number next to them. There is no explanation in the manual, so I did some research and found that they pertain to the signal quality.
Here is an explanation of what they mean:
- A: Antenna fades on internal antenna A
- B: Antenna fades on internal antenna B (not used on the AR8000)
- L: Antenna fades on the left external antenna
- R: Antenna fades on the right external antenna (not used on the AR8000)
- F: Frame loss
- H: Holds
With all the wiring in our electric airplanes, this is valuable information to have. If you see too many fades, holds, or frame losses, you can reroute things to improve the receiver's signal. That equates to safety for everyone.
Great Planes Shoestring Racer
This airplane has been out for a couple of years, but for some reason it's just now getting some attention. I bought one when it was first on the market and am just getting around to putting it together, but my first impression is, "Wow!" This has to be one of the most beautiful ARFs I've seen in a long time.
The fuselage is beautifully painted fiberglass and the wings are sheeted foam core covered in MonoKote. Assembly has been flawless, and the innovative cockpit hatch is something that all manufacturers should be doing.
The front of the hatch is held on in the usual way with two locator dowels and the back is held in place with rare-earth magnets, but they have keyed tabs for extra safety. I know magnets hold well, but I worry just the same.
With this method, you slide the canopy hatch forward into the dowel holes, then drop the rear keyed tabs into their respective slots before sliding the canopy back so the magnets catch. This provides a positive locking method that no amount of aerobatic forces can break. Paired with my Futaba T7C 2.4 GHz radio and a 6S power system, I expect this airplane to rock my world!
I'll be reporting soon on its maiden flight. I encourage you to check out the Great Planes website and look this one over closely.
Taking Off
There is just so much good stuff going on that I could ramble for pages, but I guess I should leave some space for the other columnists!
Remember to stay on top of the AMA's efforts in regard to the FAA rules coming down the road. Do not lose your hobby to complacency! Support our leaders' efforts to protect the hobby and write your congressional representatives an old-fashioned snail-mail letter. That draws more attention than a dozen emails.
Okay, off the soapbox and back to the shop!
Events and Projects
The Weak Signals Show in Toledo is a month away as I write this, but I’m already anxious to hit the road and see what’s new this year. I have managed to get ahold of the new Spektrum DX7s though, as well as the telemetry stuff to go with it for the iPad. That is really exciting! I’m also building a new electric-powered airplane just for me; no review, no article to write about it, just pure self-gratification!
Parallel Charging
I’ve gotten good responses from people who have tried the parallel charging techniques I mentioned in previous columns. I continue to use this method, but I also received questions about how to charge LiPos for the mCP X helicopter, micro airplanes, and other models.
A quick visit to the Tejera Microsystems Engineering, Inc. website showed me what I was looking for. The photo shows the board for charging four of the smallest single-cell LiPos for the micro airplanes; the adapter wire handles the larger plugs on the packs for the mCP X and similar machines. Prices are in the $8 to $12 range as I write this. The same principles apply for parallel charging these cells, so there’s nothing new to learn!
Spektrum DX7s
It’s no secret that I’m sort of a radio nut. I’ve owned nearly every brand out there and continue to use several different brands—I just like radios. I had the original DX7, replaced it with my JR 9503, and I love it. I wanted another radio, so I bought the new DX7s after seeing it was more than a remake. The DX7s is a complete redesign of the radio and now includes telemetry capability.
There will be a full review of this radio in Model Airplane News, but here are a few noteworthy aspects of the new radio. Its street price is roughly $299. You get the transmitter, the AR8000 receiver, and no servos for a respectable price.
Noteworthy Features
- Improved feel: The rubber grips and general feel of the radio are much improved. The gimbals are so smooth that it feels like a much more expensive radio.
- Easy programming: The programming is the easiest of any radio I have ever used. I pulled the transmitter out of the box and was programming an airplane before I cracked open the instruction manual.
- Power pack: One thing that caught my eye when I turned it on was the voltage. I figured the pack was bad, but when I looked in the back I saw it used a four-cell 2000 mAh NiMH battery pack instead of the 9.6-volt packs I’m accustomed to. No problem; it works great and there is a two-cell LiPo upgrade available that gives you a whopping 4000 mAh capacity.
- Throttle-hold switch: This is exceptionally valuable to electric fliers. Helicopter pilots are accustomed to having this feature, but when we select "airplane" as the model type we usually lose it. Not so with the DX7s—you can activate the throttle-hold switch regardless of aircraft mode. Safety-wise, this prevents accidental motor spooling when arming the system.
- Transmitter-on warning: The radio warns you if you forget to turn the transmitter off. I didn't know this existed until I left the transmitter on while working on the bench; a few minutes later it started beeping and dancing across the bench. The alarm can be adjusted and you can select tone, vibration, or both.
- Telemetry: With the latest Spektrum STi telemetry update for the iPad, iPod, or iPhone, you can have someone track your status while you fly or review the data when your flight is complete.
Sources
- Great Planes Manufacturing
(800) 637-7660 www.greatplanes.com
- Spektrum
(800) 338-4639 www.spektrumrc.com
- Tejera Microsystems Engineering
Transcribed from original scans by AI. Minor OCR errors may remain.
