Author: Bob Aberle
Edition: Model Aviation - 2013/04
Page Numbers: 85,86,87
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Frequently Asked Questions — 2013/04

Tips for holding wings down with rubber bands

Q568: Do you know of any criteria for determining the size of rubber bands needed to hold a wing in place? I have a 32-inch wingspan airplane with a 9-1/2-inch chord. The plans say to use two No. 32 rubber bands on each side. Since the No. 32 rubber band is 3-1/2 inches in length, that's quite a stretch!

A568: I like to use three rubber bands on each side (a total of six). In general, a rubber band can stretch roughly three times its original length. Your 3-1/2-inch rubber band should be okay on a wing with a 9-1/2-inch chord.

I use three different sizes of rubber bands for my models. The smaller or micro airplanes get No. 16. My park flyers that weigh up to 30 ounces get No. 33 rubber bands. Most of my larger airplanes use No. 64 rubber bands. If you have a large Old-Timer model with a 14- to 16-inch chord, try the No. 107 rubber bands. I purchase these rubber bands by the bag from one of the large stationery suppliers, such as Staples.

I use small No. 10 rubber bands in place of O-rings on my propeller-saver adapters.

I have some safety concerns with using rubber bands to hold down wings. If you are flying with glow power, fuel residue will likely get on the rubber bands. For that reason, I discard the rubber bands after each flying session.

I had originally thought that with electric power, because there is no fuel residue, the rubber bands could be reused a few times. I learned that is wrong! Sunlight and ultraviolet rays (especially in the hot summer months) can cause a rapid deterioration of rubber bands, so they must also be discarded after each flying session. Rubber bands are cheap, but model aircraft are not!

Don't use strip rubber similar to that of leftover rubber power motors. One break in that strip and the rubber will quickly unravel. This will be followed by the wing separating from the aircraft. Use individual rubber bands. One rubber band failure out of six will not crash your airplane.

Scalelike Wing Struts

Q569: I have a wing on my park flyer model that is built strong, using hardwood main spars. I want to add scalelike wing struts, but since the wing is already strong, I'd like my struts to be strictly for appearance's sake. What is an easy way to do that?

A569: I recently published a park-flyer version of the British homebuilt aircraft called the Ord-Hume OH-7. On that airplane, I used a pair of spruce wing spars. It was strong and didn't need any support from the scale wing struts. I added 1/8-inch plywood tabs where the strut penetrates the wing. A hole or slot is cut into that plywood insert in such a manner that the wing strut passes through to the inside of the wing. Let roughly 1/4 inch of the strut go inside the wing. Keep in mind that this joint is loose. It is not anchored with any screws and can move freely.

On the fuselage end of the strut, I added small metal tabs to the strut ends that are wrapped with wire and epoxied in place. A single sheet-metal screw anchors the end of each strut to the fuselage. These screws go into small hardwood blocks that I placed on the inner, lower fuselage sides. The wing struts tend to float in flight. This setup doesn't support the wing, but it looks good.

Make sure that your struts are constructed from hardwood such as spruce or basswood. Balsa would easily break. Don't run wire and carbon-fiber strips along the strut because this could cause RC problems. If you get stuck, send me an email and I will help you.

These are some of the special connectors and cables offered by Glen Goode of RC-Connector.com. Glen's company caters to micro and indoor fliers with a variety of connectors, cables, and special adapters.

Specialty RC Connectors

Q570: In recent times I've bought a few of the new and popular RTF micro/indoor RC models. I found that the specialty connectors used on many of these airplanes are hard to find. I like wiring my own battery cells, but trying to obtain the correct connector seems to be a problem. One of the things I had in mind was to connect two single LiPo cells in parallel so that the capacity would be doubled. Where do you obtain your special connectors?

A570: Most of us who are into micro RC contact Glen Goode at RC-Connectors.com for help. The company is based in Colorado Springs, Colorado. The website address is listed in the "Sources."

Glen carries a full line of specialty connectors for E-flite and ParkZone products and many others. He sells plain connectors, connectors with pigtail leads, adapter cables, and special-purpose cables. One that I noted is a 2-to-1 parallel connecting cable that allows you to hook up two single cells, which doubles the capacity. Your most difficult job will be to determine what you need to order.

Glen can easily be reached through his website. I highly recommend this company.

Sources

Transcribed from original scans by AI. Minor OCR errors may remain.