Blower assisted heating and defogging system for small aircraft

Abstract

For the purposes of increasing pilot visibility and comfort in small planes during winter conditions, this invention provides an auxiliary heating system. Prior to actual flight, that is to say that during start up, warm up, taxi and takeoff, a small aircraft does not intake sufficient outside air to warm the cabin and defrost the windshield. The normal heating system on a small plane depends upon ram air when the plane is flying at normal speeds. This invention consists of a simple replacement part, mainly an electric blower which sucks in air from outside the aircraft and forces it through the muffler shroud and thereafter into the cabin and defroster ducts. The system is operated by a switch located on the control panel. Once the aircraft is in flight, the system may be shut off as there is sufficient ram air to heat the small aircraft.

Description

PRIORITY CLAIM & RELATED APPLICATION

This is a continuation in-part application of U.S. patent application Ser. No. 10/808,091. Priority is claimed based on Canadian Patent Application No. 2,433,496, filed Jun. 20, 2003.

FIELD OF THE INVENTION

This invention relates to heating and defogging systems for small aircraft.

BACKGROUND

Large planes, commercial aircraft, jet aircraft and military helicopters are all equipped with very extensive heating, defogging and air conditioning systems for the cabin, whether in flight or on the ground. Multi-engine, piston powered aeroplanes have auxiliary gas powered heaters which are usually ignited immediately after the engines are started. The system includes a combustion chamber, a heat exchange system and a battery-powered blower. Soon after being ignited, the auxiliary heater soon begins delivering heat to the cabin including the windshield's defrost system without the need for aircraft motion or ram effect.

Small single engine piston powered aircraft, however, are normally equipped with simple systems which, when in flight, take in ambient air and the ram speed of the aircraft pushes the ambient air past a portion of the aircraft's exhaust system and through ducts into the cabin. Unfortunately, when an aircraft is not in flight, there is no ram air pushing through the heating system. Also, some single piston engine driven aircraft have no defrost provisions. This can create serious problems in cold, wintry conditions, particularly in northern climates such as found in Canada or the northern United States. During engine start up, warm up, taxi, takeoff prior to flight, the cabin is not heated or heated insignificantly by the existing heating system. Although the comfort of the passengers and pilot is adversely affected by the cold, a more serious problem, however, is that the pilot's visibility can be poor because of fogging windows. During taxi and takeoff, this can lead to serious accidents. Therefore, it appears that an auxiliary system, for operating in cool, damp conditions that can occur in any season but occur most acutely in the winter designed for use during start up, taxi and takeoff would provide major safety benefits plus enhance pilot and passenger comfort.

A review of the literature, prior art, and aircraft now in service, has revealed to the present inventor that this cold weather problem has not been solved, and pilots and passengers in small planes continue to complain and remain at risk because of poor visibility.

Blowers have been used in heating and cooling application for some aircraft but none address the current problem. In U.S. Pat. No. 4,490,989, issued to Keen on Jan. 1, 1985, a helicopter heating and air conditioning system is described for turbine engine-powered helicopters. The invention is not directed to temporary heating during start up, taxi and takeoff but rather to a permanent system used in conjunction with an air conditioning system. A blower is used, however, it is located downstream of a condenser and is only effective for helicopter turbines. Use of this system with small planes would not be possible.

In U.S. Pat. No. 2,265,168, issued to W. E. Huffman on Dec. 9, 1941, a heat exchanger is located within the exhaust manifold or exhaust pipes, the principal idea being that the pressure produced by a blower from the cold air inlet maintains pressure through the heat exchanger greater than the pressure within the exhaust manifold. Thus the blower is not used to push air past the exhaust manifold in the takeoff or taxiing position but rather is used to continuously keep the pressure up such that if a leak in the heat exchanger develops, CO or other exhaust gases will not enter into the system which provides warmed air to the cabin. The invention does not use a typical shrouded engine muff heat exchanger which is common in present day small planes but rather the heat exchanger is found within the exhaust manifold. Furthermore, this invention is not used on a temporary basis for start up, warm up, taxi and takeoff.

SUMMARY OF THE INVENTION

The present invention provides an attachment or add on to the existing cabin heating system of a small plane. A first embodiment of the invention is an attachment that comprises a blower connected to an air intake aperture usually in the engine housing. Once the aircraft is in the air, the system may be shut off as ram air enters through the aperture automatically. The inventor replaces the normal hose attached to the aperture with another hose and a light weight three or four-inch diameter inline axial blade blower fan. The blower is mounted on the engine compartment baffle and connects with an air duct hose which leads to the inlet of the muffler shroud or heat exchanger. The boosted air from the blower warms the cabin and defogs the windshield, much improving visibility for the pilot and comfort for the passengers.

In a second embodiment a second blower is located downstream from the muffler shroud and heat exchanger system and boosts the air velocity to increase air movement through the cabin heating and windshield defrost system.

A third embodiment also includes a blower typically located in the cabin area which receives a blend of both air provided to the cabin by the blower located upstream of the muffler shroud and ambient cabin air. This provides lower temperature air to the second blower that does then not require high heat resistance properties.

In a forth embodiment the previously mentioned lightweight inline axial blade blower is located in the cabin area to take in heated or unheated cabin air accelerate it and deliver it to the windshield. Testing has shown that in cool damp conditions, directing unheated cabin air at the windshield will remove the water vapour that has condensed on the windshield recognizing that this embodiment will do nothing to improve pilot or passenger comfort. Further, some aeroplanes begin to deliver heated air to the cabin almost immediately after start up because the inlet for the air that flows through the muffler heat shroud is propelled into the intake by the aircraft propeller but the delivered air will not generally be adequate to defog the aircraft's windshield.

In very cold conditions a system that uses two blowers is usually required to do a good job of keeping the windshield defrosted at all times after start up and before established in flight to receive ram air.

Therefore, a first embodiment of this invention seeks to provide an auxiliary heating and defrosting system, adapted to provide warmed air to the cabin and windshield of a small aircraft; said system including:

• • at least one blower adapted to be connected to a flange and an engine compartment baffle wall;
  • said flange being also connected to said engine compartment baffle wall around a pre-existing air intake aperture;
  • said system also including an air duct hose and a first clamp;
  • said clamp being adapted to secure a first end of said air duct hose around an air outlet end of said blower;
  • said air duct hose also including a second end;
  • said second end being connected by a second clamp to a muffler shroud air intake aperture;
  • said muffler shroud also including an air outlet aperture connected to a cabin air intake hose;
  • said muffler shroud encircling and enclosing an airspace about an exhaust muffler;
  • said exhaust muffler forming an existing portion of an exhaust system of a small aircraft engine;
  • said system also including electrical circuit breaker wiring and an on/off circuit breaker switch;
  • said electrical circuit breaker wiring being connected to an electrical source in said aircraft, said blower, and said circuit breaker switch;
  • said switch being located in said small aircraft cabin; and
  • wherein, in operation, when said circuit breaker switch is in an “on” position, said blower forces outside ambient air through said muffler shroud into said cabin.

In a second embodiment, this invention seeks to provide an auxiliary heating and defrosting system, adapted to provide warmed air to a cabin of a small aircraft; said system including:

• • at least one blower adapted to be connected to a flange and an engine compartment baffle wall;
  • said flange being also connected to said engine compartment baffle wall around a pre-existing air intake aperture;
  • said system also including an air duct hose and a first clamp;
  • said clamp being adapted to secure a first end of said air duct hose around an air outlet end of said blower;
  • said air duct hose also including a second end;
  • said second end being connected by a second clamp to a muffler shroud air intake aperture;
  • said muffler shroud also including an air outlet aperture connected to a cabin air intake hose;
  • said cabin air intake hose being connected to a second inline blower accepting heated air and assisting the first blower in accelerating and moving the air through the aeroplane's cabin and defrost system,
  • said muffler shroud encircling and enclosing an airspace about an exhaust muffler;
  • said exhaust muffler forming an existing portion of an exhaust system of a small aircraft engine;
  • said system also including electrical circuit breaker wiring and at least one on/off circuit breaker switch;
  • said electrical circuit breaker wiring being connected to an electrical source in said aircraft, said blowers, and said at least one circuit breaker switch;
  • said at least one switch for said blowers being located in said small aircraft cabin; and
  • wherein, in operation, when said at least one circuit breaker switch is in an “on” position, said first blower forces outside ambient air through said muffler shroud into said cabin air intake hose and said second in-line blower assist in moving greater volumes of air at higher velocities through the cabin heat and defrost system.

This invention also seeks to provide an auxiliary heating and defrosting system, adapted to provide warmed air to the cabin and windshield of a small aircraft; said system including:

• • at least one blower adapted to be connected to a flange and an engine compartment baffle wall;
  • said flange being also connected to said engine compartment baffle wall around a pre-existing air intake aperture;
  • said system also including an air duct hose and a first clamp;
  • said clamp being adapted to secure a first end of said air duct hose around an air outlet end of said blower;
  • said air duct hose also including a second end;
  • said second end being connected by a second clamp to a muffler shroud air intake aperture;
  • said muffler shroud also including an air outlet aperture connected to a cabin air intake hose;
  • said cabin air intake hose having an outlet end directing heated air into said cabin through an aperture in a cabin firewall;
  • said system also comprising a second blower inlet located above said first cabin air aperture;
  • said second blower inlet receiving a blend of heated air and ambient cabin air and directing said air to an aircraft windshield;
  • said muffler shroud encircling and enclosing an airspace about an exhaust muffler;
  • said exhaust muffler forming an existing portion of an exhaust system of a small aircraft engine;
  • said system also including electrical circuit breaker wiring and at least one on/off circuit breaker switch;
  • said electrical circuit breaker wiring being connected to an electrical source in said aircraft, said blowers, and said circuit breaker switch or switches;
  • a first switch for said first blower being located in said small aircraft cabin; and
  • a second switch for a second blower being located in said small aircraft cabin; and wherein, in operation, when said circuit breaker switches are in an “on” position, either of said blowers can be operated or shutdown then relying on forces produced by outside ambient air pushed through said muffler shroud into said cabin by ram air effect caused by forward motion of the aircraft. Alternatively, a single switch could indeed control both blowers.

This invention also seeks to provide an auxiliary defrosting system, adapted to provide air to a windshield of a small aircraft; said system including:

• • at least one inline axial blade blower located in a cabin area with an inlet end for receiving heated or unheated ambient cabin air;
  • said blower having an outlet end for directing said cabin air to said windshield for removing fog from, or preventing fog from forming on, said windshield;
  • said blower being attached to said aircraft under an upper portion of an instrument panel, said system also including openings in a dashboard of said instrument panel for allowing air to be directed onto said windshield, said system also including electrical circuit breaker wiring and at least one on/off circuit breaker switch;
  • said electrical circuit breaker wiring being connected to an electrical source in said aircraft, said blower, and said at least one circuit breaker switch;
  • said at least one switch for said blower when in an “on” position, or “off” position, can operate or shutdown said blower as required for providing good visibility for safe taxiing, takeoffs and in some cases, when the aircraft is in flight, typically shortly after takeoff or in the approach to landing phase where both the power to the engine and the aircraft's speed have been greatly reduced, air flow to the windshield due to ram effect may not be adequate to prevent the windshield's fogging without the assistance of an inline blower.

The present invention is extremely simple, but solves an old problem existing in small aircraft during winter conditions. Although there are thousands and thousands of light single piston engine powered aeroplanes in operation throughout the world and blowers have existed for a long time, practical means of providing the required air movement have never been devised. Forward curved blade blowers were generally used to provide air movement for auxiliary heating systems on larger aeroplanes. The idea of using a light weight, inline axial blade blower had never been conceived until the item of this invention. In this case inline axial blade blowers, capable of blowing approximately 100 to 200 cubic feet per minute, are used to provide the necessary air flow. LED lights and blower switch are generally attached to the front face of the instrument panel of the aircraft, close to the heater control to allow convenient and logical access to the blower controls and for receiving on/off information.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of the components of the present invention as installed in a Cessna 172 aircraft.

FIG. 2 is a wiring diagram for the same invention as shown in FIG. 1.

FIG. 3 is the front view of the control panel in the same Cessna 172.

FIG. 5 is a wiring diagram used in the Cessna 150.

FIG. 6 is a front view of the control panel of the Cessna 150.

FIG. 7 is a schematic view of the invention used in the Cessna 180 and 182 model aircraft.

FIG. 8 is an exploded view of the invention used in conjunction with a Piper PA 28 series aircraft.

FIG. 9 is the wiring diagram for the said Piper aircraft.

FIG. 10 is a front view of the control panel of the Piper PA 28 series aircraft.

FIGS. 11 and 11 a are a perspective cutaway view and side cutaway view of a second embodiment of the invention.

FIGS. 12 and 12a are a perspective cutaway view and side cutaway view of a third embodiment of the invention.

FIG. 13 is a perspective cutaway view and FIGS. 13a and 13b are side cutaway views of a fourth embodiment of the invention.

FIGS. 14 and 14a are a perspective cutaway view and side cutaway view of a fifth embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an aircraft marked generally as 1, having a propeller 1a and an engine compartment marked as 2. At the front of the engine compartment is an engine compartment front baffle wall 3a. In engine baffle wall 3a is an air intake aperture 4a. When the plane is in flight at normal speed, ram air is forced through aperture 4a with movement of the aircraft. Permanently attached to engine baffle wall 3a around aperture 4a is a flange 5. This is normally attached to an air duct hose connected to an exhaust muffler shroud (air duct hose not present in FIG. 1).

A blower 6 is attached with L-shaped bracket 7 by means of a bolt, nut and washer 10 to the engine baffle wall 3a. The bracket 7 is attached to the side of the blower by means of a bolt 9. The blower is equipped with a meshed covering 8 to avoid any debris entering the blower. A clamp 11 secures a downstream end of the blower 6 to an air duct hose 12. Air duct hose 12 is connected to the inlet hole 31 of a muffler shroud 13a. A muffler shroud is basically an enclosed space or compartment located around the muffler. Warmed air leaves the muffler shroud 13a via muffler shroud outlet hose 14 which is connected to muffler shroud air outlet 32.

In operation, warmed air moves through the firewall blower channel 15 and is then directed through cabin heater ducts 16 and defroster duct 17 to defroster nozzle 18.

It is to be understood that muffler shroud 13a, outlet hose 14, firewall blower channel 15, cabin heater duct 16, defroster duct 17 and defroster nozzle 18 are preexisting parts of the Cessna 172 aircraft.

FIG. 2 is a schematic view of the wiring diagram for the invention shown in FIG. 1. There is a blower indicator light 19 connected to the wiring system. It is mounted on the control panel in the cabin as shown in FIG. 3. The wiring system is grounded at 20 on both the cabin wall and the firewall. The blower receives power through the wiring system from the main bus bar or source of electricity in the aircraft. The bus bar is marked as 21. The circuit breaker is shown as number 22. This is connected to the blower circuit breaker switch 25 shown in FIG. 3. Wiring 23, located ahead of the firewall, connects with blower 6.

On the cabin control panel, as shown in FIG. 3, there is a cabin heat duct control 16a, a cabin air control 24, and as previously mentioned, the newly added blower circuit breaker switch 25. Numeral 26 is the flap control; numeral 27 is the avionics indicator; and a numeral 28 is the carburettor temperature indicator. The control panel is shown generally as 29.

It is to be understood that FIG. 3 is a pre-existing control panel of the Cessna 172 model series aircraft and indicates where the new LED light 19 and circuit breaker switch 25 are to be installed.

In FIG. 4, the invention is shown installed in a Cessna 150 aircraft. In the Cessna 150, there are two mufflers, each with a muffler shroud and two air intakes; hence, two blowers can be used. The muffler shrouds are shown in FIG. 4 as 13a and 13b. The Cessna 150 is also equipped with air scoops 30 located above the apertures on the outside of the front engine compartment baffle wall 3. Although only one blower 6 is shown connected to flange 5 and firewall 3 by nuts and bolts 10 in FIG. 4, it is understood that in this particular aircraft, a blower for each air aperture may be used and one air duct hose 12 leads to air inlet 31 of muffler shroud 13a while another blower 6 and air duct hose 12, are connected to an air inlet on muffler shroud 13b.

FIG. 5 is a wiring diagram for the blower shown in FIG. 4. It is similar to FIG. 2 except that when using a 24-volt system, a resistor 33 is placed in the wiring system 23.

FIG. 6 shows the existing control panel of the aircraft shown in FIG. 4. It is understood that FIG. 6 is used simply to show the installed location of the new LED light 19 and the blower on/off switch 25. FIG. 6 shows a mixture control dial 34, throttle 35, a vertical speed indicator 36, an altimeter 37, a tachometer 38, an hour and meter 39, a suction gauge 40, a left-hand fuel gauge indicator 41, a right-hand fuel gauge 42, an oil temp gauge 43 and an oil pressure gauge 44.

FIG. 7 is a schematic view of the invention as used in Cessna 180, 182 aircraft. FIG. 7 is an illustration which shows that an air intake aperture 4b need not be in the front engine compartment baffle wall but rather can also be located in the rear engine compartment baffle wall 3b. Thus blower 6 is attached to a flange (not shown) located on rear engine compartment baffle wall 3b. Also shown in FIG. 7, joined to exhaust muffler 13, are exhaust system inlets 45 and 46.

FIG. 8 shows the invention as applied to a Piper PA 28 series aircraft. The air intake aperture in this particular aircraft is located in the left-hand forward engine compartment baffle 3c. The Piper PA 28 series is equipped with fresh air inlet knob 47, a cabin heat shutoff 48, defroster ducts 49 and defroster control 50.

FIG. 9 is the wiring system for blower 6 for the Piper PA 28 series aircraft and is very similar to the wiring systems shown for the previous aircraft.

FIG. 10 is a front view of the dash 29 for the Piper aircraft, showing in addition, an ammeter 51 and a circuit breaker panel 52, as well as the other usual controls. Placement of the blower switch 25 and the LED light 19 are indicated.

FIG. 11, a perspective cutaway view, and FIG. 11a, a cutaway side view, illustrate a second embodiment of the invention. Electric blower 6 is assisted by a second blower 53 which is attached to muffler shroud 13a (warmed by motor 54) by outgoing air duct hose 14. Blower 53 increases the flow of heated air through aperture 15 located in the cabin fire wall 15a. The heated accelerated air is directed to cabin outlet air duct 16 and cabin windshield duct 17 to be expelled through windshield air duct outlet 18 located on top on dash board 55. A pilot chair 56 is also shown.

FIGS. 12 and 12a illustrate a third embodiment of the invention, wherein the second blower 57 used to assist blower 6 is located inside the cabin firewall 15a. Blower 57 accepts heated muffler shroud 13a air and propels it through cabin heated air duct 16 and windshield heated air duct 17 and out windshield duct opening 18 located above dash board 55.

FIGS. 13 and 13a show a fourth embodiment of the invention. A second blower 58 assist blower 6 to bring in heated air through firewall aperture 15 and heated air duct 59. Also attached to the blower 58 is cabin air intake duct 60 which sucks in ambient air from the cabin. Ambient cabin air and heated muffler shroud air mix in blower 58 and are directed through windshield outgoing air duct 17, to outlet 18 located above the dash board 55 to direct mixed air to the windshield.

FIG. 13b shows an alternative arrangement of the fourth embodiment of the inventor. The second blower labelled as 58b is attached, in a vertically disposed position, inside the cabin firewall 15a below the dashboard 55 and above the firewall aperture 15. Ambient cabin air and heated muffler shroud air mix in blower 58b and are directed through windshield outgoing air duct 17, to outlet 18 located above dashboard 55 to direct mixed air to the windshield.

FIGS. 14 and 14a show a fifth embodiment of the invention which is directed to removing condensation from the windshield during start up, taxiing, take off and flight. A turbo electric blower 61 is attached to the cabin firewall 15a under the dash board 55. Ambient cabin air enters through duct 62 and is expelled through duct 63 through outlet 64 directed at the windshield and located above dash board 55.

Claims

1. An auxiliary heating and defrosting system adapted to provide warmed air to a cabin and windshield of a small piston engine aircraft; said system including:

a first electrically powered blower connected to an opening in an engine compartment cooling baffle wall system of said aircraft, said blower having an inlet and an outlet end;

said inlet end of said blower receiving ambient air from outside the aircraft;

said outlet end of said blower discharging said ambient air received from outside the aircraft into a heat shroud system enclosing a portion of an engine exhaust system wherein, in operation said air is heated;

a second electrically powered blower also having an inlet end and an outlet end; said second blower located downstream of said first heat shroud system; said second blower receiving heated air through its inlet end and discharging said heated air into said heating and defrosting system; where said blowers forcibly move air through said heating and defrosting system.

2. An auxiliary heating and defrosting system adapted to provide warmed air to a cabin and windshield of a small piston engine aircraft; said system including:

a first electrically powered blower connected to an opening in an engine compartment cooling baffle wall; said blower having and inlet end and an outlet end; said inlet end of said blower receiving outside air, and said outlet end of said blower discharging said air into a heat shroud system enclosing a portion of an engine exhaust system wherein, in operation, said air is heated;

a second electrically powered blower also having an inlet end and an outlet end; said second blower located in the cabin of said aircraft downstream of said first electrically powered blower for receiving a blend of ambient cabin air and heated air from said first blower and heat shroud system though said inlet end, and discharging said heated air and said ambient cabin air through said outlet end into said aircraft defrosting system;

wherein said blowers, in operation, forcibly move air through said aircraft heating and defrosting system.

3. An auxiliary heating and defrosting system adapted to provide warmed air to a cabin and a windshield of a small piston engine aircraft; said system including:

a first electrically powered blower connected to an opening in an engine compartment cooling baffle wall system of said aircraft, said blower having an inlet end and an outlet end; said inlet end of said blower receiving outside ambient air; said outlet end of said blower discharging said air into a heat shroud system enclosing a portion of an engine exhaust system wherein, in operation, said air is heated and discharged into the cabin of said aircraft,

said system also including a second electrically powered blower having an inlet end and an outlet end, said second blower being located in the cabin of said aircraft and adapted to receive a blend of ambient cabin air and heated air from said first blower and heat shroud system through said inlet end, and discharge said blend of ambient cabin air and heated air into said aircraft defrosting system; wherein, in operation said blowers forcibly move air through said aircraft heating and defrosting system.

4. An auxiliary defrosting system adapted to provide ambient cabin air to a windshield of a small piston engine aircraft; said system including:

a first electrically powered blower located in a cabin of said small piston engine aircraft;

said blower having an inlet end and an outlet end; said inlet end of said blower receiving ambient cabin air; said outlet end of said blower in operation discharging said ambient air received from said cabin onto said windshield of said small engine aircraft, wherein, in operation said blower forcibly moves said ambient air through said auxiliary defrosting system.

5. An auxiliary heating and defrosting system, adapted to provide warmed air to the cabin and windshield of a small aircraft; said system including:

a first blower adapted to be connected to a flange and an engine compartment baffle wall;

said flange being also connected to said engine compartment baffle wall around a pre-existing air intake aperture;

said system also including an air duct hose and a first clamp;

said clamp being adapted to secure a first end of said air duct hose around an air outlet end of said blower;

said air duct hose also including a second end;

said second end being connected by a second clamp to a muffler shroud air intake aperture;

said muffler shroud also including an air outlet aperture connected to a cabin air intake hose;

said cabin air intake hose being connected at its downstream end to a second blower accepting heated air and assisting the first blower in accelerating and moving the air through an aircraft cabin heat and defrost system;

said second blower at its downstream end being connected to a duct leading to said cabin and defrost system;

said muffler shroud encircling and enclosing an airspace about an exhaust muffler;

said exhaust muffler forming an existing portion of an exhaust system of a small aircraft engine;

said system also including electrical circuit breaker wiring and an on/off circuit breaker switch;

said electrical circuit breaker wiring being connected to an electrical source in said aircraft, said blowers, and said circuit breaker switch;

said switch for said blowers being located in said small aircraft cabin; and

wherein, in operation, when said circuit breaker switch is in an “on” position, said first blower forces outside ambient air through said muffler shroud into said cabin and said second in-line blower assists in moving greater volumes of air at higher velocities through the cabin heat and defrost system.

6. An auxiliary heating and defrosting system, adapted to provide warmed air to a cabin and windshield of a small aircraft; said system including:

a first blower adapted to be connected to a flange and an engine compartment baffle wall;

said flange being also connected to said engine compartment baffle wall around a pre-existing air intake aperture;

said system also including an air duct hose and a first clamp;

said clamp being adapted to secure a first end of said air duct hose around an air outlet end of said blower;

said air duct hose also including a second end;

said second end being connected by a second clamp to a muffler shroud air intake aperture;

said muffler shroud also including an air outlet aperture connected to a cabin air intake hose;

said cabin air intake hose having an outlet end directing heated air into said cabin through an aperture to a second blower;

said second blower located within the cabin and adapted to assist said first blower to force heated air to an aeroplane's windshield and cabin;

said muffler shroud encircling and enclosing an airspace about an exhaust muffler;

said exhaust muffler forming an existing portion of an exhaust system of a small aircraft engine;

said system also including electrical circuit breaker wiring and an on/off circuit breaker switch; said switch being located within said aircraft cabin;

said electrical circuit breaker wiring being connected to an electrical source in said aircraft, said blowers, and said circuit breaker switch; and

wherein, in operation, when said circuit breaker switch is in an “on” position, said blowers can be operated, or shutdown, then relying on forces produced by outside ambient air pushed through said muffler shroud into said cabin by ram air effect caused by forward motion of the aircraft.

7. An auxiliary heating and defrosting system adapted to provide air to a windshield of a small aircraft, said system including:

a first axial electric in-line blower attached to a ram air inlet aperture in an aircraft engine cowling wall;

said first blower being connected at its downstream end to an air duct; said air duct being connected at its downstream end to an air inlet in a muffler heat shroud;

said muffler heat shroud having an air outlet connected to a cabin air intake duct; said cabin air intake duct adapted to pass through a cabin firewall to a second cabin air intake duct;

said system also including an ambient cabin air intake duct communicating with and connected said second cabin air intake duct;

said ambient air intake duct adapted to receive ambient cabin air;

said second cabin intake duct connecting at its downstream end, to a second axial in-line electrical blower;

said blower being connected at its downstream end to a duct directed at said windshield of a small aircraft;

said first and second axial blowers being connected to an aircraft electrical system and operated by at least one switch located in said cabin;

wherein, in operation said system, during take-off and taxi and idle, provides warmed engine muffler shroud air and ambient cabin air to said aircraft windshield.

8. An auxiliary defrosting system, adapted to provide air to a windshield of a small aircraft; said system including:

at least one inline axial blade blower located in a cabin area with an inlet end for receiving heated or unheated ambient cabin air;

said blower having an outlet end for directing said cabin air to said windshield for removing fog from or preventing fog from forming on said windshield;

said blower being attached to said aircraft under an instrument panel in said cabin area, said system also including openings in a dashboard above said instrument panel for allowing air in operation to be directed onto said windshield;

said system also including electrical circuit breaker wiring an “on/off” circuit breaker switch;

said electrical circuit breaker wiring being connected to an electrical source in said aircraft, said blower, and said circuit breaker switch;

and when said switch for said blower is in an “on” position, said blower can be operated for providing good visibility for safe taxiing and takeoffs.

9. An electrical in-line blower system for small aircraft adapted to heat an aircraft cabin and defrost a windshield during start-up, taxiing, and take-off, said system including a first blower adapted to receive air through a ram air inlet in an engine cowling wall; said first blower adapted to force air through a duct to a muffler shroud; said muffler shroud encompassing hot air from a muffler of an aircraft engine exhaust system; in operation said air being heated and forced through a muffler shroud outlet duct into a second in-line axial blower; said second blower being connected to a cabin air duct and assisting said first blower to force heated air into said aircraft cabin and against said windshield, when an aircraft heating system switch is in an “on” position.

10. A system as claimed in claim 5 wherein said second blower is located in the cabin side of a cabin firewall.

11. An auxiliary heating and windshield defogging system for a small aircraft comprising a first axial electrical in-line blower adapted in operation to receive outside ambient air from a ram air inlet aperture in a engine compartment baffle wall and force said air through a muffler shroud; said air, being forced through a cabin intake hose through an aperture in a cabin firewall; said system further including a cabin air intake duct adapted to receive ambient air from a cabin; said intake duct communicating with and connected to said cabin intake hose; said cabin intake hose forcing air to a second axial electrical blower; said second blower in operation being adapted to force both heated air and ambient cabin air towards said windshield; said first and second blowers being operated by at least one cabin electrical switch; said switch and said blowers being connected to an aircraft electrical system.

12. An auxiliary heating and windshield defogging system comprised of an electrical axial blower located within a small aircraft cabin below a dashboard; said electrical axial blower in operation being adapted to receive ambient cabin air and direct it through an air duct towards said windshield, said blower being actuated by a switch in the cabin, said switch being in circuit connected to an aircraft electrical system.