my Du-Bro Tri-Star helicopter. There must not be many Tri-Stars left in the world because they almost
never show up for sale and even finding a picture of one is rare. Now, however, lots of good photos
and a PDF instruction manual can be seen below.
See also the Du-Bro Tri-Star R/C
helicopter review that appeared in the
December 1975 issue of RC Modeler magazine.
My first R/C helicopter was a Du-Bro Tri-Star, back sometime around 1976 (the
year I graduated from high school). I think it was purchased through Tower Hobbies. Come to think
of it, just about every mail order purchase I have ever made has been through Tower Hobbies, but that's
another story. The Tri-Star was named so because it could be built with three different ABS plastic
body styles: standard non-scale, Hughes 500, or Enstrom. Mine never got past the standard body, which
was styled after the Scorpion home-built helicopter.
A Super Tigre .46 powered my Tri-Star. The biggest pain was the centrifugal clutch. The clutch material
that was on the inside of the bell housing had to be epoxied in place, and the darn thing never lasted
for more than two or three flights before it had to be re-epoxied. Although I never broke any rotor
blades, I spent a lot of time repairing the clutch. I built a spider type training gear for it that
consisted of five fiberglass arrow shafts and some whiffle
golf balls on the ends. At the time, gyros for the tail cost
about as much as the helicopter did ($200), so I never had the benefit of one. After learning to hover
somewhat successfully, I dared to venture into my first deliberate forward flight. It took about fine
hair-raising minutes to finally get it back into a hover where I could land. I was flying from the parking
lot of a hotel that was next to a busy highway - the the best venue for beginning flights. One thing
I remember vividly is how the metal-to-metal noise of the drive gears cause sever interference with
the 72 MHz PWM radio system (an el cheapo Cirrus 4-channel) that
caused all the servos to jitter continuously.
I went into the U.S. Air Force in November of 1978, and brought the Tri-Star to my permanent duty
station at Robins AFB, Georgia, where it hung for three years but never flew
(see photo above). After getting out of the USAF, it was sold to some guy in Annapolis, Maryland,
for about $100 (including the engine).
Du-Bro Tri-Star Helicopter Photos & Manual
This TriStar is in like-new shape and appears to never have
been flown or even have had the OS 40 engine run other than maybe on a bench for breaking in. It came
with the engine and fuel tank installed, but not with a radio. An instruction manual did not accompany
it; however, thanks to the efforts of fellow heli modeler Mr. Larry Chapman providing scans of his Tri-Star
manual I was able to create a PDF version of the original, complete with detailed assembly drawings
(click thumbnail to the right). It must surely be the last of only a handful
of Tri-Stars left in this condition. One guy wrote to me and sarcastically informed me that a Tri-Star
can be bought new in the box for $350 on eBay. Good luck with that.
The Tri-Star was broken down into subassemblies for safe shipping. Here are some detailed photos
of the Tri-Star that I took after re-assembling everything. Weight without radio installed is 98 ounces,
including the 6 ounces of lead ballast attached to the front, which is right in accordance with what
a modern 30-40 size helicopter weighs w/o electronics or fuel.
If time ever permits, I would like to replace the engine with a brushless motor, add a noise-immune
2.4 GHz spread spectrum radio, a gyro, and attempt to get 'er flying. Videos are available on YouTube
where other people have reworked some of the old 'copters and have them flying pretty well - even the
DuBro Whirlybird 505. More likely, though, it will be a hangar queen and
park suspended on a string from my bedroom ceiling until someday I decide to sell to someone who actually
will do it.
Port side, assembled (inside)
Port side, assembled (outside)
Port side w/o fuselage
Rotor head and swash plate
Tail rotor - port side
Side view forward fuselage
Starboard side, assembled (inside)
Starboard, assembled (outside)
Starboard side w/o fuselage
Rotor head - flybar control arm
Underside of rotor head
Tail rotor - starboard side
Radio equipment tray w/lead ballast
Engine heat shield
Tri-Star subassemblies as received
OS 40 engine and gear train
Gear train - rear view
Side view - fuel tank
Engine & gear train rear view
Engine & gear train, head side
Engine mounting view
Gear train overview
Shown below is a DuBro Tri-Star under construction in the winter of 2008. It is rare enough to find
a Tri-Star kit these days, but to obtain one that includes the molded Enstrom fuselage is indeed an
occasion worthy of celebration. This gem is being built by someone with a strong personal tie to the
Corporation, and hopes to have it ready to fly in time for Enstrom's 50th anniversary. He bought
it from a friend of a friend. It was not bought on eBay or any online selling venue. I will keep this
page updated with photos as they are provided.
A Supertigre engine, and Futaba 2.4 GHz radio are being used.
Enstrom Fuselage Painted & Installed on Tri-Star Frame (May 2009)
Enstrom Fuselage Trial-Fitted to Tri-Star Frame
Futaba Radio Installed in DuBro Tri-Star Helicopter
Enstrom Fuselage Cut Out & Taped Together (Feb 2009)
Note: The Vintage RC Helicopter website has a nice bit of background information and a few
photos of his DuBro Tristar.
While on the subject of DuBro helicopters, you
might recall the Whirlybird 505. There was a man in my neighbor when I was a kid that had one, and I
can remember running down the road to watch try to fly it when I heard the engine running. In fact my
ears were tuned to listening for any of his engines running the way a mother is tuned to hear her baby
crying. He used the tether method, but never got any farther than a pseudo-hover. My guess is that maybe
1% of all Whirlybirds purchased ever actually flew. The video to the left is from a helicopter event
in Dalton, GA, in September 2007.
To the right is a link to a video of the
DuBro Shark 60 actually flying. I suspect a few more of them were successful than the Whirlybird.
If you monitor eBay, you will occasionally see these models come up for auction. Be prepared to shell
out big bucks for them, though.