CL Racing
James Holland
A detailed how-to on getting started in Quickie Rat Racing
I AM SITTING down to write this column three weeks before the 2005 AMA CL Racing National Championships is scheduled to take place at the International Flying Site in Muncie, Indiana.
Although many things will undoubtedly happen that no one expects, I feel confident in predicting that NCLRA (National Control Line Racing Association) Quickie Rat will be the best-supported event of the week. It’s fun. The airplanes are easy to build, fly well, and are fast enough to be interesting, and the engines are relatively inexpensive and readily available.
The purpose of this month’s column is to help the existing competitor who is having trouble with this event or the newcomer who is considering giving it a try experience the truth of my previous statement. With this in mind, I’ll be looking at hardware, model design and construction, and actually flying the event.
I started my Quickie Rat career flying a Barracuda, which Bill Bischoff designed and Ken Smith of San Dimas, California, kitted for a few years. Although the kit has been out of production for almost five years, copies of the plans are still available and the airplane (although a bit on the large side by today’s standards) is still competitive.
Having flown a Barracuda for a couple seasons and trying two of my own designs (including a flying wing), I designed my current Omega Rat in the winter of 2001 with the aim of producing a minimal airframe that was durable and flew well.
The accompanying photographs help illustrate the materials selection and construction methods I have found helpful in producing a light yet long-lasting airframe. My design philosophy for Quickie Rat can be summed up with two familiar sayings: “Small is beautiful” and “Keep it simple.”
I keep the wing area down because the required use of a fuel shutoff means that only a moderate glide is needed, but I use a relatively large tail and elevator to provide in-flight stability and good “shake-down” characteristics.
Keeping with this philosophy, I use a minimal fuselage. The nose is only long enough to hold the engine and a compact fuel shutoff; anything else means unnecessary weight. I have found that a 5-inch tail moment seems to work well on these airplanes. If it is much shorter, the model will be nose-heavy; if it is much longer, the opposite may be true.
I use a shoulder-wing design so the fuel tank can be mounted under the wing and the tank so it is hidden behind the engine. I also use a tank fairing to smooth the rear of the model. I’m not sure how much airspeed the fairings are worth, but they certainly make the finished product look better!
I fabricate my titanium landing gear and locate the centerline of the wheel on or near the wing LE. This location is slightly less than an inch in front of the CG, and it allows me to make bounce-free, high-speed landings.
Obtaining a successful Quickie Rat requires builders to meet two objectives: strength and light weight. The increasing availability of composite materials allows us to do this to the extent that we are willing to invest time in it.
The model shown in this column features a wing constructed from 1/4 balsa (with a spruce LE and spar) and covered with .2-ounce carbon-fiber cloth from CST: The Composites Store. The resulting wing is extremely light and strong.
I always carve the tailplanes from 3/16 basswood and cover them with 1-ounce fiberglass cloth. Carefully selecting wood can yield dividends here since basswood can vary considerably in weight. To save more weight I added a black dye to the finishing resin, allowing me to simply sand the tail and spray on a clear, fuelproof topcoat to give me the finish I wanted.
One of a successful Quickie Rat’s key features is a strong fuselage. I achieve this by extending the top engine bearer for the full length of the fuselage and keying the tail into the bearer. This is matched by extending the lower bearer as far as possible along the fuselage and laminating both sides of the nose with 1/16 plywood and preimpregnated carbon fiber.
A big cheek cowl does not help much in this regard. Although it does support the wing-to-fuselage joint, it will add weight and drag if poorly done.
I install a plywood fin on my airplanes, and the reason is strictly practical. The fin will stop the elevator horn from being ripped off in the event of a high-speed turnover.
I install relatively long and strong tail skids on my models. A long tail skid avoids the severe nose-up stance which can give control problems on takeoff. Similarly, using a relatively thick wire gauge avoids the problem of a springing tail skid.
Nothing else is notable in the model’s construction. I just take my time to find the right wood and prepare the various components correctly.
Since epoxy is relatively heavy, I restrict its use in assembly to critical components such as the engine bearers and wing- and tail-to-fuselage joints. All other bonding or laminating operations are carried out with cyanoacrylate or white glues.
The typical Quickie Rat uses only two pieces of hardware that may be difficult to obtain: a fuel shutoff and a mechanical fast fill. Melvin Schuette of MBS Model Supply sells both, as do a few other individuals. The model shown uses a mechanical fast fill that Scott Jenkins of Florida built, and he does sell them. His and Melvin’s contact information is at the end of this column.
I make my own tanks, and, as mentioned, I size them to hide behind the engine. I locate the fuel feed tube at the rear of the tank (lower outboard corner) and run the vent tube from the top front outboard corner through the cheek cowl. Making tanks isn’t too difficult as long as you make accurate measurements, keep the metal clean, and use good-quality flux and solder and a hot iron.
The engine plate is made from 1/8-inch aluminum and is kept as small as possible to save weight. I drill and tap the shutoff directly to the engine plate and notch the plate to clear the tank overflow.
For the control system I use a 2-inch Fox bellcrank and a 1/8-inch-diameter wire pushrod. I use solid-wire leadouts that are a minimum of .038 inch in diameter; anything less will eventually break. (I know from personal experience!)
I finish my models with fiberglass or carbon-fiber cloth applied with a commercially available finishing resin. In addition to the weights I have already given, I use 1.25-ounce cloth on the fuselage. This appears to work well, combining reasonable strength with moderate weight.
I typically prefer to paint each model’s fuselage and leave the wings in a natural wood finish. I have successfully used polyurethane and epoxy-based paints, and the final choice is a matter of personal preference.
Engines are available from three sources at the moment: Vic Garner, Bob Oge, and Tim Gillot. I have exclusively used Garner engines for the last six seasons and have found them to be competitive.
I do recommend breaking in each engine for a minimum of 20 minutes before you put it in the airplane. Use a light-loading propeller and fuel that has 20% oil (preferably half castor) for this procedure.
Quickie Rat events are won through a combination of good airspeed and pit work. This means testing and practice. Test a number of different propeller combinations and practice your shutdowns and pit stops.
One of the Omega Rat design’s biggest advantages is the ability to make extremely fast shutdowns (approximately a half lap). I have won major races on the strength of this feature alone because it is comparatively rare to have an absolutely dominating airspeed advantage.
I hope this column is of some use to you. Please feel free to E-mail me with your comments and suggestions. I do read and respond to each E-mail I receive. MA
Suppliers:
- CST: The Composites Store
(800) 338-1278 www.cstsales.com/index.htm
- Vic Garner
832 Jefferson Ave. Livermore CA 94550 [email protected]
- Gillot Racing Products
Tim Gillot 1063 Harding St. Salinas CA 93906 (831) 449-2052
- Scott Jenkins
- MBS Model Supply
[email protected] http://members.cox.net/mbschuette
- Bob Oge
15477 Owens Rd. Hinckley IL 60520 [email protected]
Transcribed from original scans by AI. Minor OCR errors may remain.
