Frequently Asked Questions - 2010/06 | Model Aviation Library

Author: Bob Aberle

Edition: Model Aviation - 2010/06
Page Numbers: 73,74,76

Update on technology for the author's Scratch-One

Please write in with your questions; that is the only way we can keep this column format going. When referring to questions and answers that have been published (for follow-ups), provide the number as a reference.

References to addresses and Web sites are placed in a group, separate from the text, at the end of this column under "Sources."

Q449

"A few years back I built your Scratch-One trainer design that was published in MA. I recently decided to build another one to try to get my grandson interested in the hobby.

"I realized as I started this new project that a lot of our technology has changed over the past five years. So my question to you now is; do you have any recommended updates for the Scratch-One?"

A449

My Scratch-One design was included in the multipart "From the Ground Up" feature series that began in MA in 2004. It was a joint venture between MA's Sport Aviator editor Frank Granelli (covering fueled models) and me (covering electric power). The series is still posted on the AMA Web site; the Web address for the complete index is in the "Sources" list.

Several times last year readers asked if I had any updates for my Scratch-One design. To satisfy those inquiries, I wrote a brief article covering all the technology that has emerged in the last five years.

That article mentioned brushless motors, companion brushless ESCs, Li-Poly battery packs, Lithium battery chargers, and 2.4 GHz digital spread-spectrum RC systems. I also included a list of suggested new equipment that you could purchase at a reasonable cost. The equipment I recommended in this follow-up is strictly a guide—there are many combinations of motors, ESCs, batteries, and RC systems that would work equally well.

One reader thanked me for the information and suggested that I have it published in MA. I passed that on to Editor Michael Ramsey, who acted on the suggestion immediately. The "Scratch-One Technical Update" was added to the original article on the Web site as Part 9B, page 5. The Internet address to access this feature is in the "Sources" list.

Aero Craft Ltd. still sells a package containing the balsa wood necessary to construct a Scratch-One. There are no wing ribs to cut for this design. It is simple to build and is excellent as a first-time scratch-built aircraft.

Q450

"Bob I know this isn't really a question, but I wanted to mention something important that I came across that I feel would be really appreciated by your readers. It involves a Web site that almost looks like an 'on-line museum.'

Take a look and see what you think!"

A450

Since that wasn't a question, it won't get an answer. But readers sometimes contact me with interesting information about our hobby that is worth passing on. This is not your usual entry, but it provides information about something you might enjoy.

My old friend Syd Krivin of upstate New York mentioned a Web site for Collectair Aviation Art and Artifacts. The address is in the "Sources" guide.

As mentioned, this is similar to an online museum. You owe it to yourself to visit the site and search around thoroughly. There are sections featuring vintage model airplane kits, vintage model engines, plastic aircraft kits of the 1950s and 1960s, aviation book references, World War II stories, and "early bird aviators." Another area is the "Friend or Foe? Museum" of aircraft recognition. Have a look!

Q451

"I remember years ago that there was a plan service known as Sid Morgan Plans. I used to see monthly advertisements for this service in several of our hobby magazines. Is this service still available or was it picked up by someone else under a new name?"

A451

I'm into my sixth year of doing this column and am getting close to 500 questions and answers. As such, it is possible for me to repeat myself and not realize it. I remember answering this question, but it must have been quite awhile ago.

The Sid Morgan Plan Service, which was in business for at least 20 years, ended up with Frank Novack of Howell, Michigan. Frank now operates the business as "Vintage R/C Plans." Contact information is in the "Sources" list.

The connection is that Frank's wife's uncle was Sid Morgan, who had a large collection of RC scale plans. In later years he picked up the "Custom Line" plans collection done by Robert Sweitzer. I have Bob's Aeronca 7AC Champion plans, and they are super-detailed in every respect. Look up Frank's Web site and see what he has to offer.

Q452

"I own a new Hitec Aurora-9 RC system. I think it's great and I'm enjoying every minute while learning to use it. But I have noticed several things involving the transmitter charger and battery that I am curious about.

'First the charger plug is not the standard variety. Second I can't seem to get the charger's transmitter LED indicator to glow. Third, I seem to quickly run out of transmitter battery power. Have you heard anything about these issues?'"

A452

I received one of the first Aurora systems, which Hitec RCD distributes, in August last year. I flew a new model with it at the NEAT (Northeast Electric Aircraft Technology) Fair in September.

The Aurora transmitter is powered by a six-cell (not eight) 1300 mAh NiMH battery pack. To avoid confusion between a six- or eight-cell pack, the Hitec engineers employed a different—or "nonstandard"—charging plug. If you attempted to plug an eight-cell charger into the Aurora, it would not fit. That's a good idea, but one of the problems with the first chargers supplied was that if the pack had more than half charge, the red LED indicator on the charger would not glow. Even below half charge, the red glow was barely visible.

It took me a while to realize that my transmitter battery was fully charged because the LCD screen read 100%. Hitec picked up on this problem; by the time you read this, a new charger will have been substituted and the indicator will glow brightly.

On one occasion I charged my Aurora transmitter overnight and the next morning it indicated that it was only 65% charged. While pondering this, I noticed that I had accidentally plugged the charger into the trainer jack, which is located on the right-side rear of the transmitter case. Nothing was damaged, but the battery wasn't charged. Now that the red LED glows brightly, it would be obvious when the charger is plugged into the wrong jack. I still think the jacks should be different.

I also noticed that my battery tended to run down rapidly. This might have been caused by excessive current drain (which was not the case), a bad battery, or a battery with too little capacity to handle the job. I found that the supplied NiMH battery likes to be exercised or cycled when received; I cycled it a few times, and the capacity did improve.

I have seen an advertisement indicating that Batteries America now supplies six-cell battery packs made from 2000 mAh Eneloop cells. These are NiMH and have the property of maintaining 80% or more charge for up to a year. The packs that Batteries America sells come with the mating Hitec transmitter battery connector, and a pack fits perfectly into the rear of the Aurora transmitter. If you do a lot of flying, you might want to consider this.

If you do go to a 2000 mAh pack, you will have to charge it at 200 mA for at least 14 hours. You should not use the supplied charger and simply double the charging time instead.

I understand that Hitec is going to supply this system with a higher-capacity battery pack in the future, so you should have no problems.

Follow-Up to 428 (January 2010 MA, page 77)

This question and answer mentioned a tapered plastic tip that fits over the end of a CA-Sucker-type tube. I didn't know of a supply source for the yellow tips when I submitted my column.

James McAlpine of West London Models of Harlington, Middlesex, England, sent me an e-mail telling me that he carries these CA tips and that they cost 20¢ each. I've included his contact information in the "Sources" list. James also sells the "sucker" bulbs.

Follow-Up to Follow-Up to 418 (February 2010 MA, pages 91–92)

The original question and answer involved a scheme to help separate the popular Deans Ultra connectors' halves. The follow-up suggested using common Vaseline on the connector pins, because IBM had used that technique for many years.

Quite a few readers wrote in to let me know about something better, called "dielectric grease." There are many sources for this material. I found the Permatex brand (catalog item 81150) at a local Ace Hardware store. A small tube costs about $5, but for this kind of application it should last a long time.