# Prize Money

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by jedi, Jan 27, 2018.

1. Feb 2, 2018

### Tiger Tim

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I read that as non-wheeled entries can't take more than 80lbs force at a time to get them on dollies. If you had to lift up a corner to kick a dolly underneath, it has to take 80lbs force or less. This whole part could be skipped by just putting the thing on wheels, where it says that it can't take more than fifty pounds of force to push.

2. Feb 2, 2018

### BBerson

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If it weighs more than 254 pounds it will need a Special Airworhiness Certificate (EA-B). That might be hard to get since none have recently, as far as I know. Bensen may have 50 years ago.
The pilot might be required to hold a Powered Lift Certificate. Again, that might be hard to get. A few Bell pilots might have a PLC.

3. Feb 2, 2018

### pictsidhe

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I'd already assumed 103 weight for two reasons: my lack of license and 8.5' sphere. Stall speed may need a triplane.

Last edited: Feb 2, 2018
4. Feb 2, 2018

### RonL

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My big question is, would Boeing associate their name and the credibility of their engineering department to specs that seem to fly in the face of physics ?
The contest seems to originate with a woman (or girl) that has some ideas that are shallow in understanding of aerodynamics. However I have come to think this concept might be closer than most would believe.
I look forward to seeing how this develops.

5. Feb 2, 2018

### BBerson

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Yeah, I can't imagine why EAA and the other sponsors would associate with something so likely to kill backyard inventors.

6. Feb 2, 2018

### flyboy2160

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PC knows no bounds, not even physics.

Once again, I quote the great scene from Top Gun in which Jester tells Maverick "That was some of the best flying I've seen so far - right up to when you got killed."

Their stated goal of a "personal flying device for anyone, anywhere." is 100000000000000000000000000000000000000000000000000000000% B.S. Really? Anyone, anywhere is going flying? Is that person the pilot? This is total lunacy.

7. Feb 2, 2018

### oriol

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Boeing and Airbus are working on similar approaches derived from the multicopter dron concept.

Any aircraft configuration has advantages and disadvantages and it is reasonable that the most important aircraft manufacturers are exploring new ways of flying.

Perhaps the multirotor electric configuration is not the most popular for traditional full scale aircraft homebuilders (neither are gyros, helicopters or anything close to VTOL) but multirotors might very well end up becoming mainstream in the near future. It is worth to note that electric multirotor drones have been largely developed by hobbycists/homebuilders.

Oriol

8. Feb 3, 2018

### pictsidhe

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I'm highly dubious that a multirotor can meet all the go fly requirements.
Meanwhile, I have encountered a big difference in the power required to make my idea get off the ground. I think I'm going to do a subscale experiment.

9. Feb 5, 2018

### pictsidhe

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Experiment done. As expected, the pessimistic physics won. My idea will not fly.
At least I only blew two cardboard boxes, half a roll of hairy string, half a roll of duct tape and a few glue sticks. An upside is I fixed my electric leaf blower.

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10. Feb 5, 2018

### markaeric

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A quick glance at the rules gives me the impression that the requirements aren't an all-or-nothing proposition. The prize money is broken up into several categories and awarded to those who stayed below or came closest to whatever limit. So at least they haven't completely lost their minds.

11. Feb 5, 2018

### oriol

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I too did some conceptual design on paper for the Go Fly contest.

I tried to use only off the shelve components (paraglider and RC electric powerplants...) to reduce the cost to the bare minimum.
I think I can meet the size, pilot field of view cone(!) and noise requirements but not the cruise speed (30Kts) and range (6Nm) because of horsepower and battery limitations.

Although Go Fly encourages "inventors and doers" to enter in the competition, I do not think it is realistic to expect that an average homebuilder can afford to pay to build all the necessary custom components and fancy equipment to match the investment of the big ones (sponsored) teams in order to be able to compete at the same level.

Unless you get the first price it is very easy that even if you win the phase I (20000 US) or II (50000 US) prizes you will probably only afford to recover what you have invested in building your prototype.

As already stated in this thread Rutan won the Ansari prize after having invested twice the money of the prize.

Things would be different, from a homebuilder perspective, if the competitors were not to meet the thresold of the three requirements (size, noise, cruise speed) but at least two of them within the minimum possible budget as the fourth requirement to be scored on for the final prize; somehow like vintage sailplanes which can compete with modern ones in gliding competitions because of the rules scores parameters.

As a side note I do not think that the Martin jet pack could meet the noise requirements (the videos have background music), and even if they won the first prize they would not recover the investment done to have a working prototype. Which makes an idea of how much it costs to have a proof of concept proto.

Just a side note, it is quite contradictory and funny that the Go Fly offers Boeing Masters and Mentors to empower the competing teams with their advice when the rationale of the Prize is that the teams "inventors" will empower Boeing Masters and Mentors to achieve their commercial/technical goals.

Oriol

Last edited: Feb 5, 2018
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12. Feb 5, 2018

### markaeric

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IMO, the only thing more unrealistic than the totality of the technical requirements is the timetable. "Inventors" rarely have unlimited time and budget to work on their projects, nevermind a team of engineers and builders required for such and undertaking. I can't help but to feel somewhat grated by the competition.

13. Feb 5, 2018

### BJC

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Same here; that, plus the paultry prize offering, is why they never will see my machine. A pox on them for even having the contest.

BJC

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14. Feb 15, 2018

### manolis

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Hello all.

Here is a Portable Flyer wherein the design is focused on the safety, without compromising in the rest areas.

ENGINE

Two OPRE Tilting engines, each having 350cc capacity (86mm bore, 30+30=60mm stroke) preferably the PatBam version for HCCI combustion (no need for high voltage circuit).

The two engine casings are secured / bolted to each other:

to form the Portable Flyer casing.

I.e. there are two independent propulsion units, each comprising an engine and two counter-rotating propellers.

Portable Flyer total mass: less than 20Kg / 44lb.

PORTABLE FLYER SIZE

With 3-blade propellers having 39’’ (991mm) diameter,
and with 21’’ (533mm) distance from propeller axis to propeller axis,
the maximum dimension of the Portable Flyer is 39’’+21’’ = 60’’ (3.5 points (35% of the maximum Final Score) in the “compact size” scoring of the GoFly competition, sponsored by BOEING).

QUIET TAKE OFF

Limiting the propeller tip speed at only 150m/sec (44% of the sound velocity) for “quiet” take off, the resulting propeller rpm is 2,900rpm.

With 28’’ pitch and 3 blades per propeller, the static thrust at 2,900rpm is ~35Kp / 350N (at least according http://www.godolloairport.hu/calc/strc_eng/index.htm ; if anybody has another static thrust calculator, he can check it out), while the power absorbed by each propeller is ~15bhp.

At the “quiet” take off, the total upwards thrust is 4*35=140Kp (with a total mass <110Kg, this means ~0.3g upwards acceleration) and the required power from each engine is ~30bhp.

The small tip speed keeps the noise low, and the “noiseless” scoring high (GoFly / BOEING competition: the quietness counts for some 40% of the Final Score).

With 2.4:1 “crankshaft to propeller” reduction ratio, the 2,900rpm of the propellers at the above “quiet” take-off, translates into 7,000rpm for the engines.

In order a 350cc 2-stroke engine to provide 30bhp at 7,000rpm, it needs to make 30mN of torque at 7,000rpm (~90mN/lt specific torque, which is easily attainable even with 4-stroke engines).

After the take off, the engine rpm (and the propeller rpm) increase to enable a high cruise speed (above 100mph (160Km/h)).

TOP SPEED

At top speed (> 100kts / 185Km/h) the propellers rev at 4,350rpm (propeller tip speed 2/3 of the sound velocity), and the engines are running at 10,500rpm (at 10.5m/sec mean piston speed, which is still low and improves the long term reliability).
In the scoring of the GoFly / BOEING competition (see figure “speed” at https://www.herox.com/GoFly/guidelines) this means less than 0.05 points below the maximum possible (this counts for less than 0.5% of the maximum possible Final Score).

SAFETY

In case of malfunction of the one engine, or in case one propeller falls apart, or in case a transmission tooth belt is broken, or . . ., the “healthy” propulsion unit is capable for a safe landing.

With the one only engine running at 9,000rpm (mean piston speed: 9m/sec) and driving its two 3-blade 39’’ diameter / 28’’ pitch propellers at 3750rpm (2.4:1 reduction):
the total thrust force is ~115Kp,
the tip speed is 195m/sec (57% of the sound velocity),
the power required from the running engine is ~65bhp (which means: ~50mN of torque from 350cc capacity, i.e. ~150mN/lt specific torque, which is attainable by a good 2-stroke: the Rotax 850 has more than 175mN/lt peak specific torque).

With “only” 195m/sec propeller tip speed, the Portable Flyer is quiet even during an emergency landing.

FAST TAKE OFF

With both engines running at 9,000rpm, the upwards acceleration at a “fast take off” is more than 1g (10m/sec); it is like “falling towards the sky”.

Alternatively: the Portable Flyer can carry two persons (the pilot and a passenger); in this case at a malfunction of the one propulsion unit, the emergency landing is not possible (unless the one person (the pilot or the passenger) falls, preferably with a parachute).

CRUISING / CONSUMPTION / MILEAGE

With the pilot wearing a wing suit,
at 100mph cruising (87kts / 160Km/h / 44.5m/sec) the required thrust is about 30Kp (300N, 66lb) and the calculated power is ~18bhp.

(the data are taken from http://www.dropzone.com/news/General/First_jet_powered_Birdman_flight_613.html )

At cruising the propellers rev at 3,750rpm (propeller tip speed 57% of the sound velocity), and the engines rev at 9,000rpm (mean piston speed: 9m/sec)

With, say, 75% propeller efficiency, the power required from the engines is ~24bhp.
With the engines running at 35% BTE (attainable with HCCI combustion and lean mixture), the fuel consumption (gasoline) at 100mph (160Km/h) cruising is easily calculated at ~5.5lt/h (3.5l/100Km), and the mileage at 67mpg (US gallons).
For a distance of 200miles (320Km), they are required some 11lt (~8Kg) of gasoline.

Each engine has to be capable of providing, at 9,000rpm, the 65bhp required for an emergency landing (as previously described). Compared to the 24bhp required for cruising at 100mph, the engine(s) at cruising will operate at substantially light load (quite lean air fuel mixture if HCCI).

The straight line a Portable Flyer follows going to a specific destination is a big advantage as compared to a car and to a motorcycle which cover a substantially longer distance following the road.

HIGH SPEED AND SAFETY

The ability for high speed flights is mandatory for the safety; at windy weather a big size / slow moving (“hovering”) flyer is like a “feather in the wind”.
If the Portable Flyer can fly way faster than the wind, the strong wind is not a problem.

USE

In the near future the Portable Flyers (or the Personal Flyers) appear as interesting alternatives for cars / motorcycles / boats etc (which means wide use).

For special uses, the Portable Flyers appear as a passé partout.

Think of:

A “first aid” doctor arriving into a couple of minutes and landing 5m from the injured persons.

A rescue team flying to a sinking vessel.

A fireman who, at a skyscraper fire, is taking off the road and is landing in seconds on the roof of the skyscraper to help (or to take away) trapped persons (if each engine alone is capable for an emergency landing, the Portable Flyer is capable to lift, besides the pilot, a passenger (or two: the Portable Flyer mass is counted only once)).

COST

Regarding the ownership cost, a Portable Flyer like the above is way simpler than a car or motorcycle (it needs not wheels, it needs not suspension, it needs not a steering, . . .): just two simple, lightweight, vibration-free engines forming the casing, and four propellers.
Regarding the running cost, according the previous calculations a Portable Flyer appears more economical (and more green) than a car or motorcycle.

ENGINE (again)

The two OPRE Tilting engines are the heart and the backbone of the Portable Flyer.

The “OPRE” stands for Opposed piston Pulling Rod Engine while the “Tilting” refers to a valve secured on the small end of the connecting rod; the tilting valve controls the intake and the transfer (no need for reed valves or rotary valves). More at http://www.pattakon.com/pattakonTilting.htm

Each “crankcase” (actually the space underside the piston crown, inside the piston) runs not-pressurized.

The thrust loads are taken at the cold ends of the engine, away from port openings.

The synchronizing gearwheels between the two crankshafts run unloaded and serve as balance webs, too.

Each engine, alone, is perfectly vibration free, and is driving its own pair of counter-rotating propellers (zero gyroscopic rigidity).

The short piston stroke (30mm) allows high revs at low mean piston speed (reliability).

With HCCI (i.e. spontaneous) combustion into a compact bowl, the over-square design is fine; the combined stroke is 30+30=60mm; with 86mm bore, the design is by far less over-square than the famous Ducati Panigale 1299 (60.8mm stroke, 116mm bore).

The pulling rod architecture increases substantially (~40%) the piston dwell at the combustion dead center enabling more “constant volume combustion”.

The single-piece “pipe-like” casing improves the stiffness, the lightweight, the simplicity and the low cost.

THEORETICALLY SPEAKING

All the previous are just theories; yet, interesting theories.

The safety is the “big issue”.

Having two independent propulsion units (each alone capable for emergency landings),
having also a parachute (for just in case, say when it runs out of fuel),
having (optionally) three small wheels like:

for emergency airplane-like-landing on a road or on a flat field,
the safety appears better than the safety provided by the conventional airplanes and helicopters.

AMENDMENTS ARE REQUIRED

In the previous the GoFly competition (sponsored by BOEING) was mentioned only as a reference point.
Surprisingly (because the BOEING is involved) they focus on the quietness and on the maximum dimension (8.5ft maximum) of the device: 90% of the total scoring is for the noiseless take-off / landing and for the maximum dimension of the Personal Flyer.

SUMMARY

In the double-propulsion-unit OPRE Tilting Portable Flyer presented above, nothing appears near or beyond the current state of the art limits.

Lightweight carbon-fiber propellers of various designs and sizes are available in the market at low prices.

Toothed belts are common place for power transmission and revs reduction.

The structure of the Portable Flyer utilizes the engine casings as its backbone.

The perfect vibration free (including both, inertia vibrations and power pulses vibrations) is a requirement when a powerful engine is to be directly supported / secured on the body of the pilot/rider; otherwise a long (say of one or two hours) flight would be a torture.

The counter-rotating propellers eliminate the gyroscopic rigidity and allow the pilot/rider to vector the thrust immediately and effortlessly to the desired direction.

Every ounce of mass that can be omitted from a personal flyer, must be omitted. The more the mass of the flyer, the more fuel is required for a specific range and the more challenging the take-off / landing becomes.

The peroxide JetPacks consume some 30Kp of “fuel” in half a minute.
The jet powered personal flyers (Yves Rossi like, Zapata like etc) consume their fuel in ten minute, or so (BTE less than too small).
The electrical personal flyers are based on batteries; and the existing batteries have an energy density several dozens of times lower than the fossil fuels (gasoline, kerosene, Diesel etc). The energy density of the power source is more than important for a flying device.

The body and the eyes and the senses of the pilot/ride are available; why not to use them as the fuselage and the sensors and the control system?
Isn’t this what the birds are doing?
Relative to the birds, the low power to weight ratio of the human body is the only thing that restricts us from flying / hovering.
This lack of power is what the OPRE Tilting engines and the propellers are curing at a true “neutral” and efficient way.

Thanks
Manolis Pattakos

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15. Feb 15, 2018

### BJC

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Manolis:

Are you building one?

No graphics are needed for your reply.

BJC

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16. Feb 16, 2018

### Victor Bravo

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Looks like he just pasted the entire proposal into one forum post, graphics and all

17. Feb 16, 2018

### BoKu

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My money is on Zee.aero, but I can't tell you why.

--Bob K.

18. Feb 16, 2018

### bmcj

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Manolis, you’ve shown that before. I want to hear about it after you’ve built and tested it.

19. Feb 16, 2018

### choppergirl

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..click pics to zoom..

Not so much as starting a contest, but I've been thinking about giving out trophies for "first flights of your first finished homebuilt airplane".

At one time I got an awesome deal on a whole bunch of Ez Build Plastic Model airplanes (Fokker Triplane, DVII, Spad, Camel) and they all come with a nifty little detachable black trophy stand. I bought them in a big bulk pack, 3 each for 15 total planes. Rubber lift transfer printing of all images and lettering on the planes, (I forget the technical name of it, but its super accurate printing).

The kit includes a mini eyeglass screwdriver, and some assembly required, but literally 10 minutes and boom you are done, it's kind of fun, they are such a piece of cake. Anyway, you'd be proud to get one, they aren't shabby, for dust collectors. Dirt cheap for me to buy, or they were at one time. ($5 each). Dirt cheap to ship, unassembled. Probably fit in a orange padded envelope or USPS flat rate box. I've since given most of them away to kids as gifts, so other than the four I kept for myself, I'd have to get more. All I'd have to do would be to use a Click-Clack machine to Clack out your name and airplane and date and boom instant trophy for your desk or shop or shelf. I have other printing thermal labelers, but I saw in Huntsville Air & Space, NASA labeled the old Apollo modules inside using that state of the art for 1967 Click Clack labeler, so I'd run with that. Age makes those labels come off over time and curl up, but, I'm sure I could come up with a fix. Like drill holes on each side of the plastic label and pop rivet those bad boy labels in there! If I included a block of routed, stained wood as a base to mount it on and provide a little balast, it'd really look sharp and fit for a trophy case. No shortage of nice wood scraps or stain from my dad's cabinet shop. Probably would not make anyone work harder or faster to finish their plane, but I dunno, nice sentiment after all that work you did, that someone at least gives you a prize or award for making it all the way to the end. Guys like medals and prizes and stuff. Good idea/bad idea? More homespun than Boeing I know, and you don't have to be a member of EAA or anything, or even like me. Show me your plane, show me you in it and it getting off the ground on it's own, show me the date on your watch or newspaper, and that's good enough for me. No rules. Pretty informal, honor system, no point cheating for a$5 plastic plane, you know if your plane flies or not.

Or, not appealing at all? You guys probably would rather get a new tool for your shop... as an award, i.e., something useful. It'd have to be something super cheap though (I'm not made of money), and symbolic, with enough surface area to engrave or label on it. Bucking bar, tape measure, <insert idea here>, etc.

More than one can win (at least until I run out of money). If you're already building your first plane, well, you've already entered, so to speak..

Just something more to add to the fun of it I guess. Dunno, it's always fun for me, whenever I find a surprise in my mailbox. Which one will you get, you don't know. People have mailed me random airplane parts, and junk, so... I don't mind sending others stuff.

Last edited: Feb 16, 2018
20. Feb 16, 2018

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