RC Jets
Jim Hiller, 6090 Downs Rd., Champion OH 44481
AMA Safety Committee and Turbine Rules
This has been a busy time for the AMA Safety Committee.
The turbine-engine rules changes requested by the Jet Pilot's Organization (JPO) have been acted upon. Everyone who holds a turbine waiver was solicited for input on the JPO request prior to changes.
The latest revisions to safety regulations for model-aircraft gas turbines are available on the AMA website: www.modelaircraft.org.
The thrust-to-weight ratio rule has changed significantly. It is still 0.9 pounds of thrust per pound, but installed thrust is now used to calculate the thrust-to-weight ratio instead of the manufacturer's certified thrust rating for the turbine. Normal installations result in some loss in rated thrust, so this will provide room for models that are close to the limit.
Turbines can be detuned by the manufacturer, with appropriate documentation, to help the modeler comply with the thrust-to-weight ratio limit. Adding ballast for the purpose of reaching the thrust-to-weight ratio is not allowed.
The thrust-to-weight rule has also been revised to allow greater-than-0.9-to-1 thrust ratios if a speed limiter is used. Maximum speed will need to be set to less than 170 mph, unless the aircraft kit manufacturer has set a limit. In that case, the manufacturer's limit will be the maximum speed allowed. In no case will speed settings of more than 200 mph be allowed. This will be good; we can get better-than-1-to-1 thrust-to-weight ratios yet maintain constant speed throughout looping maneuvers with the use of a speed limiter.
The technology of speed limiters has been slowly growing. The Golden West Models Hammer is available with optional speed control. Mini Hobby ATL produces a device called Autospeed to automatically control speed. I don't know if either unit will comply with AMA's intent of this rule, but I will be checking them out for additional details.
Flexible fuel bags will no longer be allowed in turbine aircraft, so the time has come to update those early turbine models to solid-type fuel tanks.
Turbine speed events will not be allowed.
Controllable rudders will be required on all turbine-powered Sport and Control aircraft, effective January 1, 2001. This will give pilots who are flying models without rudders time to retrofit their aircraft.
Safety barriers will be required, protecting the pits the entire length of the flightline. These rules are intended to improve safety at the jet meets.
Many of us have seen models on takeoff or landing leave the runway at high speed. Turbines do not throttle down as fast as piston engines, leading to incidents where a model loses directional control on the takeoff roll and comes dangerously close to, or goes into, the pits.
Model meet Contest Directors (CDs) who allow jet demonstration flights will need to comply with the safety-barrier rule. Jet modelers who make demonstration flights should warn the CDs of this uniquely turbine rule.
These rules changes were initiated by the JPO request, then AMA sent copies of the request to turbine-waiver holders for their input. I've been told that a good number of turbine holders responded, and their input was important in the final rules decisions. We couldn't have asked for better handling by the AMA.
A quick verbal survey of active turbine fliers at the Toledo Expo showed a positive reaction to these rules changes. I was amazed by the favorable responses, since these rules do require additional effort by turbine modelers and ops of major events. Not everyone likes all of these new rules, but they do make quite an improvement.
The Jet Pilot's Organization is to be commended for taking the lead on these rules requests. The rules actually promote the technology improvements we enjoy as turbine modeling continues to develop. It's up to us to live up to these rules; we don't need violators ruining our excellent reputation.
Toledo Weak Signals RC Expo — Highlights
As I write this, the annual Toledo Weak Signals RC Expo was last weekend (April 7–9). With it came a chance to view first-hand all the new models and products available for jet modeling.
The jet display table featured some of the most beautiful scale and sport jets imaginable, but all was overshadowed by Jim Weigle's Concorde. Although it's not a model airplane as normally defined, it is incredible.
Power for the Concorde will be four AMT (Aviation Microjet Technology) 450s (the new name for the AMT Olympus). All-up flying weight is expected to exceed 200 pounds, with redundant radio systems to be developed before the first flight. Jim hopes to have the Concorde ready for test flights later this year.
The Concorde falls well outside the AMA guidelines, hence the issue of whether or not we will see it fly at future AMA meets. After an appropriate test period, I hope some arrangement can be made for public demonstration flights of the Concorde; it should be awesome.
Numerous scale and sport jet models filled up the display table. It's a shame there is now only one category in which these models can compete; event organizers combined scale jets and sport jets this year. The winners in the jet category will truly have earned their awards; the competition is tough.
Exhibitors and New Products
Jet Hangar Hobbies brought many of its line of Turbax ducted-fan-powered models to Toledo, including the ever-popular F-86 Sabre jet, the A-7 Corsair II, and an F9F-4/5 Panther.
Larry Wolfe brought a prototype BAE Hawk—a proposed Almost Ready-to-Fly (ARF) model. Hidden in the back of the booth was an initial pull from the molds of a Mirage, all painted up in ARF form. Larry is pursuing this venture to bring .45- to .48-powered ducted-fan ARF models to the market. Details will follow as this project comes together.
The availability of .40- to .48-size engines has improved dramatically. The K&B .48 is back in production under new ownership, with the first run of K&B .48 ducted-fan engines already underway. Contact Jet Hangar Hobbies for availability, or check the website at www.jethangar.com.
DL Aeromodeles brought a fine example of the Aermacchi MB-339 Sport Scale model, designed for ducted-fan or turbine power. This straight-wing aircraft is proving to be a popular Sport model. It is sized right to provide excellent handling characteristics for experienced jet modelers and for those fresh from starting into ducted-fan modeling. Wingspan with tip tanks is 67 inches.
DL Aeromodeles also produces the Cyclone Sport jet, available in ducted-fan or turbine power.
Top Gun Aircraft displayed the F-15 Eagle series—available in four versions, depending on your needs. Ultra Eagles are set up for the Byron fan units—available from Top Gun Aircraft—which make a great setup for the sport flier operating from tight fields or grass strips. The Eagle Pro series and the Interceptor are popular for Dynamax and Ramtec ducted-fan units.
Also on display were two of the F-16C top composite models. These are large scale models, intended for turbine engines. Models of this size and quality do not come cheap, but the performance lives up to the cost. To help the affordability of this type of model, a sport landing gear is standard, with an optional scale gear available at a cost premium.
Century Jet Models (CJM) brought out the prototype of the 1/6-scale F9F-8 Cougar. This model will complement the 1/5-scale MiG-15 kit nicely. Both models are intended for use with ducted-fan or turbine power. The Cougar is a large model, creating quite a presence. Look for CJM to keep the price right on this jet, as it does on all its other ducted-fan and jet models.
Century Jet Models also has numerous retractable landing gear and struts available for all your modeling needs, including all accessories required for options such as gear doors, cockpit cylinders, and valves. Contact www.centuryjet.com for additional information.
Bob Viollet Models (BVM) brought an impressive display of products to Toledo, including all the miscellaneous items one could ever need to build sport jet models, right up through the most complex scale jet models. These products go a long way to simplify your ducted-fan and turbine experience, and they are developed by a man who flies his products as often and as hard as any modeler would.
I fell in love with Bob's new F-100 Super Sabre prototype, on display in the booth. This model received the admiration of many jet modelers, who are just waiting for final development of this kit. The kit should be available by the end of the year; this type of model takes time to develop to BVM's standards.
The BVM kit line is incredible; to check it out for yourself, try the BVM website at www.bvmjets.com.
AMT is now Aviation Microjet Technology, representing its manufacturing and development of turbines in the U.S. The turbines have also been renamed:
- Mercury → AT180 (17-pound-thrust)
- AT280 (27-pound-thrust)
- AT450 (42-pound-thrust)
These are the same AMT turbines that have proven themselves many times at the flying fields. AMT couldn't help itself; it had to throw a teaser on the table: a 1,500-pound-thrust turbine, intended for company growth and beyond the model-airplane market. The window among model airplanes, RPVs (remotely-piloted vehicles), and full-scale aircraft continues to narrow. AMT maintains a website at www.usamt.com.
RA Microjets (RAM) was on hand in Toledo with the newly approved RAM 1000F—a 28-pound-thrust turbine. This is in addition to the popular RAM 750—an 18-pound-thrust turbine. The turbines are similar in size, with only minor weight gain in the RAM 1000F. The 1000F is one of the new-generation turbines that is taking the world by storm this year. Check out RAM's products and support at www.ramicrojets.com.
Closing
Summer is almost here, so it's time to quit writing and finish painting my Razor—test flight is only days away.
See you at the jet meets. MA
Transcribed from original scans by AI. Minor OCR errors may remain.
