Vintage R/C Helicopter - Du-Bro Whirlybird 505

This is the only model R/C heli designed with the engine on top of the main rotor. The idea died with this model in 1975 or thereabouts. This was very low cost to manufacture compared to all other heli's but had too many drawbacks to succeed in the quickly advancing world of rotary flight. Thanks for the piloting compliment.

Some good points though were crisp altitude control authority and an easy-to-master tail rotor (yaw) function. The Schluter was the complete opposite in how it handled. Good forward flight speed meant wind wasn't as big an issue but the tail rotor was always moving whenever power was changed, which was all the time if a consistent altitude was desired. The Cobra was also huge and heavy, being 6 feet long and over twice the weight (about 10 pounds) of the Du-bro. Crashing the Cobra really hurt!

The difference in price for these two groundbreaking aircraft was also staggering; About $1000US for the Cobra (radio equipment and 10cc engine not included) vs $125US for the Du-Bro 505. Also no engine (6.5cc) or radio gear included. The drawbacks to the Whirlybird were almost worth spending the extra cash on the Schluter as the Du-Bro is very loud (no practical way to add a silencer - can't rotationally balance the rotorhead) and its limited controllability and speed kept it grounded in wind.

The Cobra was very "normal" as it used a central transmission with a centrifugal clutch at its input and two output shafts, one to drive the anti-torque tail rotor and the other to spin the main lift rotor. The transmission was sealed and contained an ounce of oil. Transmissions are precise and expensive devices and greatly increase the complexity of the aircraft. The Whirlybird also has a few gears but they only spin the tail rotor and are under far, far less load, hence run dry.

For a number of years prior to 1971, many free-flight helicopters used the torque reaction system to provide power to spin the main rotor blades. Only one R/C heli took advantage of this ultra simple propulsion system and you just watched it fly. When R/C helicopters first were seen by the public in 1970, there were only two successful machines - The Du-Bro Whirlybird 505 and Dieter Schluter's Bell AH1 Cobra. The differences in the designs were staggering and each model had certain advantages.

Top mounted motor crossed my mind b4 but I didn't realy give it much thought(has it been done in mass b4?) cos' I thought the top weight might make it very unstable, I guess I'm wrong. I'm more of a dreamer than a do'r but I have some Ideas 4 other thing's if anyone want's 2 bounce some with me. I'll just tinker with my hola in the meantime - might get the E-Flight Blade 400 next pay day but I cringe at the thought of stacking 500bucks kit. It's got the 2.4g 6ch control so I think it's worth it.

wow, i have never seen the top mounted motor before. thats cool. i just got into the electric cp helis and they are a blast. great flying!

Thats pretty cool. It's like a Bigger Cox Heli with motor and prop on top but RC. There was not much torque on the body with this kind of power, so gyros were not really needed. Great job. 5 stars! Keep em coming.

You're welcome. Stay tuned, there will be more :D

There's no "I.Q." implied...

Stupid video..

Mate. What can I say.. I absolutely enjoyed this video. Appreciate you sharing this to us. Chris From New Zealand..

Haha ya, it would do the Whirlybird 505 justice only if you made it like a video they'd show on discovery channel, like the ones where they tell you about vintage cars. That's what this is, a vintage rc heli.
I'm sure your "to do" list is pretty long, I can appreciate that, there are so many things that don't get done because they keep getting bumped. Glad you think it's a great idea tho.

You have a great idea. I'll have to give it some thought so what I explain will be understandable to all. OK, a new addition to my "To Do" list.

You're right!! Found nothing! Forget even the details, couldn't even find the basics. Well, if you're ever inspired and want to make a nice youtube video on how it works, I'm sure every rc heli enthusiast would enjoy it! Until then, it remains a mystery!