August 1999 R/C Modeler
Vol. 36 - No. 8
Site Sponsor: R/C Modeler
Name SR-71 BLACKBIRD
Aircraft Type R/C Rocket Glider
Mfg. By Thunder Tiger/Ace Hobby Dist., Inc., 116 W. 19th St., Higginsville, Missouri 64037, (660) 584-7172
Mfg. Sug. Retail Price $199.99
Available From Retail Outlets
Wingspan 18 Inches (Approx.)
Wing Chord 17 Inches (Approx.)
Total Wing Area 325 Sq. In. (Approx.)
Fuselage Length 34 Inches (Approx.)
Stabilizer Span N/A
Total Stab Area N/A
Mfg. Rec. Motor Range E15-P Rocket Motor
Rec. Fuel Tank Size N/A
Rec. No. of Channels 2
Rec. Control Functions Elevons
Basic Materials Used In Construction
Fuselage Molded Styrofoam
Building Instructions on Plan Sheets N/A
Instruction Manual Yes (14 pages)
Construction Photos Yes
Radio Used Hitec Focus SSII AM
Motor Make & Disp. Aerotech E15-P Rocket Motor
Tank Size Used N/A
Weight, Ready to Fly 15 Oz.
Wing Loading 6.65 Oz./Sq. Ft.
WE LIKED THE:
"Almost Ready To Fly" assembly - glue on fins, install batteries, apply decals, and go fly; exciting launches, and gentle glide.
WE DIDN'T LIKE THE:
Water type decals, price of rocket motors, and launch guide tube material.
Thunder Tiger's ARF SR-71 is designed as a rocket-powered glider which is available either as a free-flight model or as radio controlled. In this report, we're reviewing the R/C version of the plane.
The Almost Ready SR-71 comes in a plain brown box measuring 36" x 23" x 3-3/4". Upon opening the box we found the plane, radio, and launch equipment well protected by foam and cardboard dividers. The plane itself is formed from a hard shell, smooth surface foam material that is prefinished in flat black enamel. The "almost" in almost ready to fly means that all that has to be done to get airborne with this one is to glue the two fins into slots provided in the fuselage, apply the decals, put the batteries in the model and transmitter, assemble the launch platform, slide the rocket motor in place, and you're ready for the first count-down.
As mentioned above, the only assembly required is to glue the vertical fins into the slots provided in the fuselage. The launch stand is also simple to assemble. Just push the three legs into a center section, bolt on the blast plate and guide rod. (Note that it disassembles just as easily for transport.) And that's it. Construction done.
Already painted in flat black, no other finish is required on the hard surface. To our surprise, water-based decals (remember them?) are included to give the plane a realistic scale-like appearance. We shot some flat clear enamel over the decals to help protect them.
The SR-71 is powered by an Aerotech E 15-P rocket motor, which does not come included in the kit. Housed in plastic, the unit is simply inserted into the back of the fuselage. Because the rocket motor had a loose fit and we were concerned that it might fall out before it was fired, we jammed it in place with a piece of toothpick which worked fine. A launch control device included with the kit ignites the motor, but a 12-volt battery is required. We used the same gel cell that we use to power electric starters at the field.
The factory-installed R/C system is the Hitec Focus II, single stick AM system. Because the radio is "sealed" in the fuselage during manufacture, we could not see the servos or the "mixer" used to provide "elevon" control. However, the radio worked flawlessly during our tests, and was very easy to use.
Before our first launch, we checked the C.G. with a motor installed. The C.G. was right where the instructions said it should be. The control movement was also checked to assure the control surfaces operated as they should: right stick and the right elevon moved up and the left moved down, and vise versa. Pulling back on the control stick gave up elevator, and vise versa. While the instructions did not indicate how much control surface deflection was required, since the servos and linkage were factory installed and inaccessible, we had to assume the set-up was correct.
The author and helper (Dick) after another successful flight.
Next, we carefully went through the launch preparations. With the SR-71 on the launch rod, a final check of the controls was completed and, of great importance, we verified that the control surfaces were centered. After we checked to assure the launch control unit wires were not attached to the battery, the rocket end of the wires was attached to the rocket motor igniter wire. We then connected the wires to the 12-volt battery and installed the safety key into the launch control unit. At that point, we got a green and red light indicating that the system was A-OK and ready for the launch.
After checking to assure that the area and sky above were clear, we began our 5-second countdown - and pushed the launch button. After a few sputters from the rocket motor, which seemed like hours, the motor came to life and literally catapulted the 71 into the air with tremendous velocity. It was awesome, to say the least. Keeping our hands off of the controls, as cautioned in the instruction booklet, was easy because we were busy watching it climb out. The plane made some slow axial rolls as it blasted skyward leaving behind a great smoke trail to mark its path. On the first launch, we estimated that the plane reached at least 600 feet altitude in a few seconds.
When the motor quit, the plane leveled out and we pulled full "up" trim on the transmitter as recommended in the instructions. Then we enjoyed a gentle glide about the field to touch down nice and soft in a grassy area adjacent to the runway. Maintaining airspeed was easy and the turns were comfortable. Landing requires that you maintain some airspeed for a decent flare before the touchdown.
Flushed with the fun of success, we flew an additional three flights. On one of the launches, the plane seemed to hit an altitude of about 900 feet. It was just a speck way up there. All of our flights were smooth and gentle. No problems whatsoever were experienced. We estimated that the flight duration ranged from 30-45 seconds, not long on time but long on fun.
When setting up the landing, be sure to pick a nice grassy area. One time we landed on the blacktop runway and scuffed the cardboard tube launch guide on the bottom of the SR-71 pretty badly and also scratched the bottom of the fuselage. (Maybe a plastic launch guide tube would have been a better choice.) The launch guide tube was easily repaired with some CA. Scratches in the bottom of the fuselage were lightly sanded, then touched up with some flat black enamel - just like new and ready for the next blast-off.
Thunder Tiger's SR-71 is a real "blast" to fly and, in our view, is well worth the price. Needless to say (but we will), it's a real change of pace. And what an attention getter! The only cautions we want to mention are (1) keep you hands off of the transmitter during the launch or, as pointed out in the instructions, it may become the fastest and most expensive lawn dart in town, and (2) that in view of the fact that assembly is so minimal and the R/C system is factory-installed, it is not intended as a toy for the young ones. A package of two rocket engines sells for approximately $10.00-$12.00. While it is very easy to fly and should not be any problem for any experienced R/C pilot, we do feel that some experience in flying R/C models is recommended. It should also be flown at a rocket-designated field or an R/C flying field where rocket-powered R/C flight is permitted. On the other hand, while we haven't flown it as a slope plane, the way it flies suggests it would also fly well in the updrafts. Our test flights were flown in a 10 knot wind and it handled very well. When flying in a wind, though, watch those downwind turns.
As far as we're concerned, flying the SR-71 was a "thumbs up" test. All you need to fly is some glue for the fins, four AAA batteries for the receiver, eight AA batteries for the transmitter, and some rocket engines. Available at your local hobby shop, Thunder Tiger's ARF SR-71 sells for a street price of approximately $150.00. Remember, that includes the Hitec R/C system - not bad for something that good.
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