Awesome Hydrogen Peroxide Rocket Tipped Helicopter!

a reply to: vonclod

98% hydrogen peroxide is highly corrosive when in contact with human skin as it is an aggressive oxidizer. However by comparison to say Hydrochloric acid it is relatively non corrosive.

Personaly I am unsure why this would ever be hailed as "green solution" the chemical manufacturing process involved in this materials production is pretty much the complete opposite of "green"

a reply to: Dabrazzo

How is it pressurized to come out of the nozzles so fast?

a reply to: OrionsGem

Decomposition due to a catalyst...

When brought into contact with a catalyst, the peroxide decomposes into a mixture of superheated steam and oxygen, at around 500o centigrade. Fed directly to an expansion venturi, thrust will result.

This basic process was used as the principle of Walter's so-called "Cold" Motors. (ME163a)

Or..

A hydrogen peroxide-powered motor is based on the decomposition reaction of hydrogen peroxide. Nearly pure (90% in the Bell Rocket Belt) hydrogen peroxide is used. Pure hydrogen peroxide is relatively stable, but in contact with a catalyst (for example, silver) it decomposes into a mixture of superheated steam and oxygen in less than 1/10 millisecond, increasing in volume 5,000 times: 2 H2O2 → 2 H2O + O2. The reaction is exothermic, i.e., accompanied by the liberation of much heat (about 2,500 kJ/kg), forming in this case a steam-gas mixture at 740 °C (1,364 °F). This hot gas is used exclusively as the reaction mass and is fed directly to one or more jet nozzles.

Have a look at some of the bell rocket belts... you know, from james bond, and some of the 70/80's USA football/olympic opening ceremonies... same basic rocket system as a peroxide tipjet.

a reply to: Dabrazzo

Because nowadays 'green' means $$$$$

a reply to: CovertAgenda

I know this is simplistic but is it similar to mixing baking soda and vinegar then directing the mix thru the nozzles?

OG

a reply to: vonclod

Exactly. Thats why it makes such a good disinfectant and (hair) bleach at lower concentrations.

Anaerobic bacteria cause many skin infections . They cannot grow in the presence of oxygen. When a typical over-the-counter 3 percent hydrogen peroxide solution is applied to a wound, oxygen is released. An enzyme called catalase breaks down hydrogen peroxide, releasing oxygen and water. While the water cleans the wound, the oxygen kills the anaerobic bacteria.

Hydrogen peroxide can bleach hair on the skin. It breaks the chemical bonds of the color-causing molecules in the hair, the chromophores. When the chemical bonds of the chromophores are broken, the molecules no longer have color.

Maybe thats why the 'peroxide blondes' are so bubbly and OTT.... its the extra oxygen from the peroxide!!!

a reply to: OrionsGem

Yes and no..... and apologies if i complicate the process but...

The BS/V chemical reaction actually occurs in two steps. First, there is double displacement reaction in which acetic acid in vinegar reacts with sodium bicarbonate to form sodium acetate and carbonic acid:
NaHCO3 + HC2H3O2 → NaC2H3O2 + H2CO3
Carbonic acid is unstable and undergoes a decomposition reaction to produce the carbon dioxide gas:
H2CO3 → H2O + CO2
The carbon dioxide escapes the solution as bubbles.

No because there are a few steps in this reaction (wasted energy?).... Yes because the decomposition of the carbonic acid to CO2 is similar...

The decomposition of H2O2 under the presence of a catalyst (and/or heat) creates an Exothermic decomposition, some of which feeds back into the process, accelerating it. (self accelerating decomposition temperature). And of course steam (and o2)at that temperature expands rapidly (thru the nozzle). In a way, similar to using expanding steam in a loco engine (ok went to a railway museum today so still topical). Funny to think that way... a steam powered helicopter...

I seem to recall reading somewhere that weight for weight, the decomposition releases as much energy as dynamite. (will have to confirm that though!)

originally posted by: CovertAgenda
a reply to: OrionsGem

Yes and no..... and apologies if i complicate the process but...

The BS/V chemical reaction actually occurs in two steps. First, there is double displacement reaction in which acetic acid in vinegar reacts with sodium bicarbonate to form sodium acetate and carbonic acid:
NaHCO3 + HC2H3O2 → NaC2H3O2 + H2CO3
Carbonic acid is unstable and undergoes a decomposition reaction to produce the carbon dioxide gas:
H2CO3 → H2O + CO2
The carbon dioxide escapes the solution as bubbles.

No because there are a few steps in this reaction (wasted energy?).... Yes because the decomposition of the carbonic acid to CO2 is similar...

The decomposition of H2O2 under the presence of a catalyst (and/or heat) creates an Exothermic decomposition, some of which feeds back into the process, accelerating it. (self accelerating decomposition temperature). And of course steam (and o2)at that temperature expands rapidly (thru the nozzle). In a way, similar to using expanding steam in a loco engine (ok went to a railway museum today so still topical). Funny to think that way... a steam powered helicopter...

I seem to recall reading somewhere that weight for weight, the decomposition releases as much energy as dynamite. (will have to confirm that though!)

'


Way to complicated, can we just say they make a fizzy mix and the fizzy turns the rotors?

OG

a reply to: Dabrazzo
oops wrong reply

a reply to: OrionsGem

FLOL apologies....

Or maybe... Vindaloo curry and Tequila ... eat... mix.... wait....explosive decomposition outgassing... >>>thrust...

Who needs rotors anyways????

I've just scanned through this OP and let me add one possible answer to the tail rotor question. It may be that this helicopter doesn't meet some requirements for directional control to be certified. IIRC, FAR part 27 sets the requirement for helicopters certification including covering it's ability to maintain direction control.

I met a fellow, several years ago, who used the H2O2 tip jets on a gyrocopter at the Popular Rotorcraft Convention at Mentone,Indiana. He made zero length take offs using tip jet but the rotor RPM management looked marginal. After take off, he would shut the jets down and then flew on the gyro's own power.

If you want any yaw control authority with no significant forward airspeed (as in a hover), you're going to want a tail rotor. Sure a tail rotor isn't needed (no torque with a rotor-jet, not going to start spinning at least), but an airfoil alone isn't going to do much to let you steer until you get moving. Well, I suppose you could use a V-tail or or some other offset to make use of downwash from the lift rotor - but maybe that presents its own problems?

a reply to: pauljs75

I think that the army evaluated 3 tip jet helos of which 2 had small tail rotors. The Djinn used a rudder in the jet exhaust for direction control. The Hiller H-32 had an inverted "V" with a tail rotor but later version had a rudder, on an angle, that used rotor down-wash for directional control.

The major complaint, that I've heard, was slow rpm recovery while maneuvering. The tip jet rotor doesn't have an immediate rpm recovery as rotors driven mechanically. I've also heard the noise was a factor but other conventional helos are also very loud (H53).