“HYDRA” – AEROHOD

Categories Design
A few years ago we managed to build a very successful vehicle — herohitonakomode. Testing of this device proved to be very successful and we wish our experience could use a lot of homebrew.
Your device we have manufactured for the production of boats, type “amber”. A few words about its capabilities. “Hydra” (as we called it) can move across the ice at speeds up to 90 km/h on the water (with passengers) — up to 45 km/h. the Machine is easy out of the water to ice and Vice versa, from the ice into the water. Transportation “Hydra” to the river is its course for a few minutes on the boat, installed wheels, and it’s easy transformirovalsya in the aircar.
 
But the universality of the “Hydra” is still not the main “highlight” of the device. The main advantage in the highly original the drive from the engine crankshaft to the shaft of the propeller. The role transmission plays a V-belt CVT from a snowmobile “Buran”, which gives aerobody with such automatic transmission of a number of advantages over devices that use other ways of converting engine power into thrust.
 
Briefly, here are the main benefits of using V-belt CVT to drive the rotor.
 
1. Our engine is extremely easy to start hand starter; air screw remains stationary and starts to spin only when the rotational speed of a crankshaft of the engine reaches 2000 min-1.
 
2. After starting the engine can run at idle and not rotating the air screw, which greatly increases the safety of the vehicle aredigital.
 
3. When idling the crankshaft of the engine “Hydra” is not experiencing a substantial alternating loads, as it happens in those power plants, where the propeller is mounted directly on the motor shaft. This greatly increases the life of the crankshaft and its bearings.
 
4. Propeller Hydra spins smoothly, without sudden jerks, which significantly reduces the requirements for attachment of propeller. On “Hydra” propeller mounted on the shaft, only the cylindrical pin Ø 6 mm.
 
5. The gear ratio of the CVT V-belt is automatically set by the centrifugal regulator and the load clutch of the CVT depending on the engine speed and the resistance to rotation of the propeller. This means that in case of engine operation with fully open throttle the engine speed will be 5000 min-1 regardless of whether the boat to stand or to move at full speed. The frequency of rotation of the propeller will vary depending on the speed of herohitonakomode.
Not to be unfounded, we illustrate this with experimental data: with screw Ø 1200 mm (step 450 mm) engine develops 5000 min-1, and the propeller — 2880 min-1; with screw Ø 1200 mm (pitch 600 mm) rotational speed of the crankshaft of the engine 5000 min-1, and the frequency of rotation of the screw — 2190 min.-1. These data were obtained with the engine in place with a fully open throttle of the carburetor. For comparison, the same data when driving apparatus with a speed of 80 km/h: ground screw at the same rpm of the crankshaft has a rotational speed of 4,500 min-1, and the second — 3850 min-1. Interestingly, we put on our machine screws of different diameters, steps and with various width blades, but static thrust it does not go beyond 75…85 kgs. In fact, the thrust in this case depends mainly on the efficiency of the propeller, since the rotational speed of each of the screws makes the CVT corresponding to the maximum thrust.
 
The foregoing allows to conclude that the power plant with V-belt variator greatly simplifies the selection of the propeller and enables the motor with all screws and at all speeds to operate at maximum capacity.
 
A few words about aerowisata, which is operated by us for over three years.
 
“Hydra” is made on the basis of serial welded aluminum boats of type “amber”. The hull had to be reinforced by additional stringers and frames. On several stern frames fixed aluminum profiles “area” — they have become a mainstay of the propulsion system, captured in these “corners” through saylenbloki. These aft frames of United additional stringers (dural “parts”) in order to load from the propeller installation is evenly distributed on the largest possible number of frames. This measure was justified – it significantly increased the reliability and durability of the structure.
 
For our “Hydra” required centering, substantially shifted back. To accomplish this, we moved the driver’s seat and the passenger to the rear. This required the manufacture of parubky to close the crew and bring the windshield to the driver. Polirovka — plywood, covered with fabric in nitrocellulose lacquer and then painted with nitrocellulose.
 
The bow of the boat is reinforced is required in order to ensure that it can be installed steerable nose wheel or a ski. The steering mechanism of the car “Zaporozhets”. The place of fastening of the steering mechanism is reinforced dural “parts” and channels. Himself steering gear is mounted inside the boat.
 
All three wheels Hydra quick thanks to the use of pins with swivel tongue; they are installed with the use of shock absorbers.
 
The mounting area of the rear wheels also had to increase. The hull is riveted flanges, which are flush with them welded tube it are inserted the axis of the rear idler arms. Axis “pendulums” are fixed rods, which are fixed to the housing pins with swivel tongue. This method of attachment of the wheels allows a single person for min 2…4 install the wheel on the Hydra or to dismantle them (of course, when Hydra is on the water). On land it is necessary to do together: assistant for the wheel Assembly supports the chassis.
 
Installation on the boat wheels allows the Hydra to move (of course, outside the settlements) and land — for example, from pond to pond.
 
To get to the pond in the summer, on
 
To get to the pond in the summer, on
To get to the pond in the summer, on “Hydra” are mounted wheels — one front (top photo) and two rear (photo below).
 
For driving on ice or Packed snow skis are used: front Quad (its length is 1.2 m, width 0.5 m), coated on the bottom “stainless steel” and is filled with foam polystyrene, as well as two rear rigidly mounted in the rear of the hull on the M8 bolts passing through the frames. These skis carved from birch bar, and their feet covered with stainless steel sheet and provided with undercuts.
Winter version of aerohod
Winter version of aerohod “Hydra” on the spring ice.
 
When using the “Hydra” in the snowmobiles used are installed on the transom of the boat scraping brakes. Well, when driving on the wheels the brake pads of the rear wheels are cable-driven scrapers — this allows for braking in all modes use a single pedal.
 
Fuel tank capacity of 55 liters is located under the power plant, fuel to the carburetor of the engine is fed by a pump.
 
Propeller one-piece, carved from a block made up of carefully preferovany to each other, the boards connected to the package with epoxy. The best results for our power plant showed a screw with the following settings: diameter — 1.4 m, 0.5 m, width of the blade — 0,105 m. With this screw herohitonakomode speeds when driving on ice — up to 110 km/h, on water — up to 45 km/h.
 
In the manufacture of propellers we use more simple technology than mentioned in the technical literature. Here are her milestones. When marking the workpiece having the shape of a parallelepiped, it should be borne in mind that the rear edges of the blades are one of the edges of the workpiece. Well, the height of the front edge of the plane in which lie back of these edges is sought by us derived the empirical formula:
 
hPC=bzag*hscrew/Ltech.,
 
where b isthe saw — cut width, hscrew — step screws Ltech. circumference at the given radius of the screw.
 
Since a rectangular blank width constant, the pitch of this screw will also be constant. From this it follows that to determine the height from the bottom plane of the workpiece to the front edge at any cross section of the screw must the product of the width of the workpiece on the pitch consistently sharing on the lengths of the circumferences of each of the radii on which are these calculation sections. After marking the workpiece, the excess material is trimmed (please note that the upper part of the screw is convex). The angle of each of the cross sections of the blade can be easily controlled by the markup.
 
In preparing this material, we do not have drawings, our apparatus as it is assembled from mass — produced elements, Motorboats and variator to the engine. The main idea of the construction is in the successful combination of propeller and engine connected to an automatic transmission. Therefore, we encourage homebrew in practice to assess the performance of the power unit is applied to various vehicles — trikes, boats, snowmobiles, aarohanam.
 
N. RADIONOV, N. DRACH, Yakut ASSR, and the settlement of Chersky-1

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