Hiller Flying Plateform Planning, All Ideas Highly Appreciated, Aircraft Noob

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Aviator2

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Ok, gotcha- there’s more to the need for a reduction drive than just the tip-vortices.

Keeping in mind that the majority of readers probably are only tacitly familiar with the physics of these sorts of systems, I’d like to ask the next “layman’s” question regarding this subject:

If the engine weren’t to exceed, let’s say, 100 HP, and the co-axial propellers weren’t to exceed, let’s say 5 feet in diameter, then would it be correct to say that the engine-propeller-duct combination would function optimally without the need for a reduction drive?

Or is a reduction drive necessary in all engine-prop combinations (except, of course, where the engine’s horse power is so low that a reduction isn’t necessary)?

In other words: would the fiberglass shroud negate the need for the reduction drive in this configuration?


 

BBerson

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I don't think I made my point very well.
In general, more gear reduction is needed for vertical (static) thrust (lift) than for an airplane flying at some forward speed.

Helicopters have large reduction ratios (perhaps 10 to 1) to get low disc loading( study and understand disk loading, see post #5)
Low disc loading gives more thrust per Horespower and allows for operation over dirt, sand and water. A small high disc loading prop only works well on concrete, it will blow around and injest dirt.

p.s. any info on the photo (with blue shroud)?
 

Dana

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The need for a reduction drive is a function of the propeller diameter and the rpm... if the tip speed is much over Mach 0.8 you need a reduction drive (or a smaller propeller). Even lower tip speeds may be desirable to reduce noise.

Most airplanes do not have reduction drives. Early (WWI) era airplanes turned huge (for the engine size) propellers slowly, at 1200 rpm or so. Later engines turned faster, but redrives were still uncommon except for higher power engines like WWII fighters. There were a few geared engines in the GA world postwar, but redrives really got common with the advent of much faster turning 2-stroke engines. Redrives still aren't common on most 4-stroke aircraft engines.

For a ducted fan, you probably won't need a redrive, depending on the diameter. The max tip speed still applies, though.

I doubt the blue fan in the above picture would work... way too small for adequately low disc loading. Ducted fans are also very sensitive to inlet disturbances, and there would be a lot of disturbance from the pilot's body and the engine.

Dana

The most important and least understood aspect of life in America is stupidity. -- Frank Zappa
 

Aviator2

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Here is a clearer picture of that platform.



Forget it, i can't get pictures to tranfer over when i'm using this stupid color-nook thing, hafta wait til i get back on monday to post the pictures. -Aviator2
 
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Aviator2

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Vertipod

The name of the company that was attempting to build that particular flying platform is Air Buoyant, and the vehicle is (or, was) called the Vertipod.

It’s been more than 6 years since anybody has reported anything about this particular flying platform.

Air Buoyant president and CEO Pete Biter claimed that the kit for the homebuilt version was going to be in the $10,000.00 range.

I have read on various websites that the machine's engine is 50 horse power.

Here’s some more pictures of the Vertipod:


 
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BBerson

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I only see one blade in the photos, how does that work?
Is that you in the photo?

The last photo is photoshopped. ( the safe way to fly:gig:)
 

Aviator2

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No, I am not in any of those photos, and have never seen that machine in person.

Has anybody heard anything more of Protomate's project, that is- the guy who originally started this thread intending to build a flying platform?
 
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Aviator2

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We need a low cost contra-rotating alternative!

Besides that, there’s another point I’d like to make on this conference, because this is a unique place to make it. And that is: that I feel- and I believe that a lot of homebuilders around the country and world feel the same way as me- that there had ought to be manufactured, a very high quality, simplified, but much less expensive, co-axial, that is to say- contra-rotating, rotor head, and it should be offered to the public, mainly homebuilders and experimental builder types.

This theoretical rotor head wouldn’t come with any reduction drive built in, as most of the contra-rotating drives now have. Nor would it have any pitch-change linkages or mechanisms. This would reduce manufacturing complications and costs enormously.

The unit would consist of either 3, or 4 miter gears, 2 shafts (one inside the other) and several heavy-duty bearings that would attach the shafts together. And some type of attachments at the tops of the shafts that the home-builder could attach propellers or blades onto.

When you turn the single shaft at the bottom, the top two shafts would contra-rotate. If the home-builder needed to, he could consult a machinist in order to assist in the proper attachment of his engine(s) to the input shaft.

If the home-builder desires mechanisms in order to connect more than one engine to the shaft, or he needs reduction drives, then he could add these features in addition to the simplified coaxial rotor head.

This sort of a unit could be useful on homebuilt ultra-light planes, powered parachutes, trikes, experimental helicopters (like the Air scooter), and, of course, home-made flying platforms like the Hiller VZ-1.

I believe that this simplified, “home-builder type” contra-rotating head could be manufactured and sold retail for around one thousand dollars.

And I think a lot of home-builders would love the flexibility of having this option to choose from.

So, what do ya’ll think about this idea?

See the unit below in motion at: http://www.youtube.com/watch?v=4mWe9EnW9hE
 

Aviator2

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Paucity of Subject

BBerson, on the last post you said, “I only see one blade in the photos, how does that work?”

I kinda doubt that that particular platform ever got off the ground- of if he did fly I’ll bet he spun like a whirligig.

It’s too bad that there isn’t some way to counter torque other than coaxial rotors, but I’m sure that every idea has been tried.

Conventional helicopters use a tail rotor, tip-jet copters use compressed air or gasses, and contra-rotating blades seem the only other means of canceling torque.

I’ve seen some other fanciful, but probably unrealistic attempts at canceling torque on rotor systems, but if they’d worked, then we’d probably have seen them around.

That’s why I was advocating for a (relatively) inexpensive contra-rotating head for home builders in the last post.

Maybe someday one will be available, but I wonder how much call there’d be for such a unit- even if it were high quality and inexpensive.

The only successful Hiller type flying platform in existence that I know of is Ben Blakeborough’s machine in Australia, and possibly the Hummingbird built by Dr. Rafi Yoeli. (with the exception of the original Hiller machines that are in museums)

 

BBerson

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Yep
Most of these "flying platforms" "jet pack" or other VTOL schemes are scams.
The question of safety has never been solved.
 

Aviator2

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Safety

That raises a good point- the question of safety.

If you have a Hiller VZ-1 type of flying platform with one, single engine- then you have no emergency landing capability whatsoever- if the engine stalls- that is where you will drop (and crash) - period.

If you have three engines, like one of the prototypes that Hiller built for the Navy (and later, the Army), then you no longer have a light, personal aircraft that can be controlled by kinesthetic control- you might as well build a GEN H-4 helicopter instead.

So, you end up with a platform with two engines that are connected to a gearbox that allows both engines to turn both propellers- even if one engine isn’t running. This is how the Nolan Brother’s 51-HJ helicopter fixed-pitch rotorblades were supposed to function- if one engine stalled- the other, still running engine, would keep turning both blades and allow the helicopter to make an acceptable landing.

That may have worked ok with big, long helicopter blades. But here’s the question about the flying platform:

What would’ve really happened if the original, 2-engine VZ-1 platform were in straight and level flight, let’s say- 20 feet above ground level, and moving forward at 20 MPH, and one of the 40 HP engines suddenly quit.

Would the craft drop at a rate from which the pilot could recover? Would there be a sudden, uncontrollable oscillation due to sudden loss of lift? Would things happen too fast in this craft in this condition for a person to react quickly enough?

When I sit back and simply try to imagine this scenario- my gut feeling is that the incident would not end well. Of course I could be wrong- and I hope I am. But the Hiller Platform was a unique aircraft in several ways.

And so the question is- could the original VZ-1 Hiller Flying Platform make an emergency landing on one engine- or does this particular style of platform have a built-in, irreparable design flaw?
 

Aviator2

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But would it have worked?

In the book “Vertical Challenge- The Hiller Aircraft Story”, in the chapter “The Mature Years”, in the section about the VZ-1 Flying Platforms, it says: “…the Army, after taking control of the flying platforms from the Office of Naval Research, requested all future Hiller Flying Platforms be equipped with a special gearbox that allows each engine to turn both propellers- even if one engine stops running…”

It goes on to say that all of the succeeding platforms were indeed equipped with these types of gearboxes.

So we can draw the inference that the platforms were (and still are- in the museums) equipped with the gearboxes that would’ve allowed both props to keep turning in the event of one engine failure.

But the question is: Assuming that they were so equipped- how effective would that system have worked with only one 40 HP engine suddenly doing all the work?

It never happened on one of these platforms, so we can probably only make educated guesses about how effective this system would’ve been on this aircraft.
 

Aviator2

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Flying Platform LLC

Hey, folks- it's been almost a full year since we discussed anything about the Hiller type flying platforms on this conference, but I have learned of a new start-up company in Florida called "Flying Platform LLC", does anybody have any knowledge on this outfit?

The company displayed a non-flying, static prototype platform at a Florida airshow recently. Their aim is to have a working prototype completed and flying by June of this year.

Their web site is http://flyingplatformllc.com

The owner of the company, Warren Novack, is very knowledgeable about the Hiller type designs, and his company seems to have mastered the best flying platform design for a home-builder type of craft.

If this company comes to fruition and starts selling flying platform kits to the public- it could sure save homebuilders who are interested in owning a Hiller-type flying platform a lot of design and fabrication work!! (imagine- you'd have the fiberglass fairing, counter-rotating prop mechanism, propellers and framework , already assembled- and together in one convenient kit!!)

The company plans on letting the builder obtain the two required Rotax 503 engines himself, or substitute with other types of engines, if the builder desires. (they plan to include adjustable prop-speed ratios built into the counter-rotating prop mechanism for this purpose)

So, what do you think? Has anybody heard of them? Could this possibly be the "real deal" for homemade platform builders?

Here's a couple of videos pertaining to the Flying Platform LLC company, and machines.

http://www.youtube.com/watch?v=t5mSZtiE5qE

http://www.youtube.com/watch?v=aD6Om6LoERM



 
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Dana

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I never hold out much hope for a company that publicly displays a "non flying prototype" before initial flight testing. And what's with this statement on their website:

"Enter the twenty first century of advertising with your very own flying platform!"

"Advertising?"

Dana

The number of elected federal officials is limited to congress, the president and the vice president. That's only 537 people. The federal bureaucracy numbers in the millions...
 

JamesG

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"Enter the twenty first century of advertising with your very own flying platform!"

"Advertising?"
Just think of the publicity potential as, in front of the media and untold smart phone cameras, the platform slices and dices its way through a crowd of spectators with your company logo all over it!
 

Aviator2

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Just think of the publicity potential as, in front of the media and untold smart phone cameras, the platform slices and dices its way through a crowd of spectators with your company logo all over it!
Haaaa!!! "slices and dices through the crowd while advertising..." That IS funny.

I believe that this company may very well turn out to be a reputable kit supplier for home-built flying platforms. I contacted them with questions about whether the propeller drive system allows one engine to disconnect from the system in the event of an engine failure, and whether the other engine can then take over turning both propellers- allowing for a single-engine emergency landing.

They said that their kits will indeed have this type of drive system- and that emergency landings on a single engine will be possible.

They were more vague on the other question- pricing. I asked for a "ball-park" price range, but they don't want to mention any figures as yet. It is important to home-builders to have some idea of what they can expect to be paying for a kit, but maybe it's simply too soon in the company's evolution to actually know how much their product will cost.

One of the promotional videos mentioned "perhaps the price of a Harley", but Harley Davidson motorcycles can have a very wide price range- from what I have known of them.

In any case, I'm hoping that Flying Platform LLC is successful, and that their product will soon be available.

If I hear/ see anything new or relevant, I'll post it.

 

Aviator2

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A little Bit of Update

For those interested in this subject (the possibility of an actual home-made flying platform) I have just a scant, little bit of update from the Flying Platform LLC Company, of Lake placid, Florida.

I had contacted them recently asking about progress on their company built prototype, kit availability, prices, etc.

Their spokesperson said that they are still developing the mechanical aspects of their platform- especially the drive assembly. He added that it will still be "A few more months before we are in production".

Being the unusual type of aircraft that this is, and having observed decent aircraft projects being developed and built, common sense would tell me that this time frame, for them, would probably be in the neighborhood of six more months.

This is, of course, just a guess on my part, and six months is a liberal time frame, but this company is tackling the whole counter-rotating drive-train mechanism on their own- plus the fact that this particular drive-train will be user-adjustable for rotation speeds- in order that the home-builder will be able to select from a variety of engines- no small engineering feat.

The company intends to provide every prefabricated part in their kit that's necessary to build a Hiller-style flying platform for the home-builder- except the engines and propellers (but, as we all know, there are enough engine and propeller companies out there to fill this need). Good quality used engines and props also seem like a good way to go for the home-builder, if he wishes to save on those aspects.

I also inquired about the price, and the spokesman mentioned an estimated kit price of about $20,000.00 without the engines and props, of course.

He said that the estimated price could fluctuate up or down slightly, but once again- my common sense would say to me that the 20K estimate is probably pretty close to what you can expect the final price to be, when production and sales begin.

If the company produces a high quality kit, and all the systems perform as advertised, then surely twenty thousand dollars worth of work and design has gone into the kit that you'd buy.

But remember, you still need to purchase the engines and propellers, and that's going to add at least thousands to the total price.

I believe that the kit price is a smidgeon high for most, or at least the average home-builder. (Of course- there are plenty of kits and planes that are at, or well above, this 20+K price.)

I believe that a Hiller-style platform could be built for less than the projected kit price, but of course- it would be an aircraft of proportionately lower standards and safety.

In any case- I hope to build/own/fly a Hiller-style flying platform someday (probably won't be this summer however).

Imagine flying into the air show on one of these things?

 
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