Editor note: This article started out as an April Fool's post and has since turned into an incredible discussion on giant scale variable pitch applications.



This post has been moved into this forum to continue the great discussion.


Variable Pitch goes BIG!!
article by: Jeremy "Toro" Billeaudeaux

For the first time, a giant scale variable pitch application has been successfully designed, built and flown by a group of modelers from South America. Hailing from Santiago Chile, these engineers have accomplished what was previously thought of as impossible – giant scale variable pitch flight. Pilot, Mario DeSantos states in his thick Spanish accent “ I can’t believe this backward propeller idea actually work”.

As a group they were motivated to continue an experiment that had been forgotten some years ago with the new advent of the VPP systems being offered by Hobby-Lobby, and other manufacturers. “Witnessing the foamy do flips around itself was out of my mind” De Santos stated, “We need to do that with glow plane, but how?” That’s where Armand Manillo stepped in.

A Mechanical engineer by trade, Armand, already had a design in his head having recently been bitten by the heli-bug. That’s where the brains popped in taking the basic design of a raptor 90-tail rotor system, putting it on steroids and beefing it up for OS 1.40 use. The mechanism itself looks almost identical to the raptor setup, Manillo stated. The exception being the actuator coming off the side and activating the slider via bell-crank instead of a linear system like the raptor setup, also an adaptor to prevent the slider from hanging up on the threads of the Shaft on the O.S. was constructed. Propeller use comes from a custom built fully symmetrical design that obtains +10 and –10 degrees pitch at full deflection. Now for you non-heli guys, a heli hovers at around 6 positive with a whole lot less RPM’s than a 1.40. The whole unit is machined out of T6 aluminum.

The 2 machinists that created this masterpiece also have a place in the modeling community. The first an RC car enthusiast has built several custom pieces for his racers, the second a friend of Armand’s is a fellow heli-guru that operates at the same club as Armand. Both of these guys wanted to witness something spectacular to be the cutting edge of the RC world. They poured many, many hours after work machining the parts to make this project come to light. When asked about their failures that they had, they said “ too many to list” “We had so many my boss get angry with us for using up all the stock we have.”

When faced with these difficult challenges it only drove the urge further for this team to succeed. Faced with countless unsuccessful test flights, the group would re-group, re-gather, and re-build so many airframes time after time. Discouragement set in, but one small success lit the fire underneath the group some months ago.

The test bed was an old Hanno Prettner pattern ship that had been handed down so many times it had hangar rash from ¾ of the RC pilots in Chile. I even think KIWI had his hands on this one once. They fashioned a rather unfashionable exterior setup on the bird that they were able to get consistent runs with. They were able to taxi, and ground handle backwards, but up in the air was a different story. From forward flight they would have so much aerodynamic force on the propeller they were constantly breaking components. Until finally they found a system to institute the pitch change more slowly much like a servo saver on an RC car.

This was the group’s first success. They were able to stop the airplane in mid air, and allow it to fly backwards for 20 feet or so before it would fall out. With more practice eventually timing was learned and they were able to stop the airplane, put it in a nose down attitude, and through several pitch changes able to keep the airplane upright for several seconds. Eventually they figured out how to back the airplane up with more thrust application and arrived to the point you see here. I must say impressive!!!

So where do we go from here? Will we be seeing this on a 40 % soon? Will it become standard issue in the 3D world, or will the next Shootout freestyle be done with VPP? Who knows? But I have my speculation.

It was only a matter of time this was accomplished. Having seen leaps and bounds in the electric market, I knew it was only a matter of time to see this on a glow plane. These Chileans have truly set the bar to a new level. Will we be seeing a unit mass-produced soon, perhaps, but unlikely. I would venture to see more testing done on this, and expect to see it in the states in April of 2007. All I know is that this is amazing.

Good job Mario, Armand, Caesar, and Carlos. You guys are over the top, and we at the Giants think this deserves a giant tip of the hat.

While all of this is coming in is second hand, our friends down south promise to send us more images of exactally how they made this happen.

The video below was caught during a recent airshow in Santiago during a noon time VPP demo. Remember where you saw it first... A FlyingGiants exclusive!

wrong vid man thats a vid of two mankeys talkin to each other

Whoa neat

Wow! Amazing stuff and the video makes it look so easy. Where can I buy one of these...

Finally!!!! I've been waiting for this for so long!!! Just wait until I put one of these on my Pattern plane for the upcoming season, being able to slow the downlines to a crawl, I love it!!!

This is the best thing that's hit the R/C market in 20 years!!!

Any of you guys that haven't seen the vid yet, it's engineering genius!!

SIMPLY AMAZING!!!!!!!!!

I want one...now...right now!!!!!

Huh

am i missing something , or is this just about Penguins, Cars and icecream????????????

ROFLMHO I think many of us fell for a joke.


50%

April fools day. Look at the top of the homepage

Damn

Must get photo shop

Yeah!! Some april fool!!
It just hit me!!
Its a good one!! Ha Ha Ha!!

Good one Jeremy, I think we all fell for it! I even put my order in!

Huh.................... Oh I get it now its April fools day. Thanks for getting me all excited.

Hey MAX!! the videos wrong.

Yes April fools day is today, but ONLY the top of the page reflects this!
This article is legit.
I have seen the actual Video, Kiwi's buddy, who you can see in the picture filmed it in Mini DV , it 's as clear as a bell!!

MAX FIX THE LINK!!!!

hmmmm, awfully small spinner assembly to house an entire VPP unit... and thta shadow seems to be backwards...

I hate you max...

You got me