CA1171292A - Propellants - Google Patents
PropellantsInfo
- Publication number
- CA1171292A CA1171292A CA000163326A CA163326A CA1171292A CA 1171292 A CA1171292 A CA 1171292A CA 000163326 A CA000163326 A CA 000163326A CA 163326 A CA163326 A CA 163326A CA 1171292 A CA1171292 A CA 1171292A
- Authority
- CA
- Canada
- Prior art keywords
- asbestos
- motor according
- rocket motor
- propellant
- propellant charge
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K9/00—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
- F02K9/08—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof using solid propellants
- F02K9/32—Constructional parts; Details not otherwise provided for
- F02K9/34—Casings; Combustion chambers; Liners thereof
- F02K9/346—Liners, e.g. inhibitors
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Paints Or Removers (AREA)
Abstract
A B S T R A C T Canada The emission of smoke from rocket motors, especially those using "smokeless"
double-base propellant systems may be reduced by using as the inhibiting coating on the propellant and/or as thermal insulation an elastomeric composition comprising a silicone rubber filed with asbestos.
The asbestos should preferably be fibrous with an aspect ratio above about 10 : 1 and should comprise at least 10% w/w of the elastomeric composition.
Preferred silicone rubber are room-temperature curing organopolysiloxane/
alkyl silicate systems.
double-base propellant systems may be reduced by using as the inhibiting coating on the propellant and/or as thermal insulation an elastomeric composition comprising a silicone rubber filed with asbestos.
The asbestos should preferably be fibrous with an aspect ratio above about 10 : 1 and should comprise at least 10% w/w of the elastomeric composition.
Preferred silicone rubber are room-temperature curing organopolysiloxane/
alkyl silicate systems.
Description
-- 3L1'7~LZ~
The in~ention relates to rocket motors, especially those employing double-base propellants, and to means or reducing the smoke emission therefrom. The expression rocket motor as used in this specirication re~ers to a casing vented a-t one end and containin~ a combus-tible propellant charge.
It is an essential feature of line-of-sight optically guided missiles that smoke emitted during flight must not obscure the missile or the target. In the case of military weapons, smoke is additionally undesirable since it assists an enemy in pin-pointing the launch area. Most double base propellant systemsare, in themselves, relatively smoke free, but even rocket motors employing such propellant system still produce unacceptable levels of smoke emission, a significant contribution being that from the inhibiting coating applied to the solid propellant to produce constant mass rate burning, and also the thermal insulant between the propellant charge and the motor casing.
The term "double-base prope].lant" as used herein refers to propellant systems containing both nitro-cellulose and a nitrated polyhydric alcohol, eg nitro-glycerine, tri-ethylene ~0 ~Jlycol dinitrate or di-ethylene glycol dinitrate. Composite modified double-base propellants containing ammonium perchlora-te produce e~haust containing hydrogen chloride which forms mist in moist air and hence such composite modified systems are not generally employed when a smoke-free system is required. How-ever, the present invention normally will reduce the smoke ernis-sion from the inhibiting coating and thermal insulation even in these systems.
Further, the invention is not limited to double-base systems, but may be employed to reduce the smoke emission from rocket motors employing any propellant system, althoucJh rnaximum beneflt will obviously be ob-tained when the propellant sys-tem itself is smoke-free or "low smo~e".
Currently used lnhibitors and -thermal insulants, for e~ample cellulose acetate and ethyl cellulose, both plasticised ~ith phthalate esters and "Hypalon" rubber~ (chlorosulphonated polyethylenes) give unacceptably large amounts of smoke and often show other undesirable properties such as high nit:roglycerine absorption or low softening temperature. Silicone elastomers ~0 have many desirable properties for use as inhibitors and/or thermal insulants such as low temperature flexibility, low nitro-glycerine absorption and high thermal stability, but when unfilled or filled with commercial fillers such as CaCo3 sio2 or Tio2 give copious smoke emission. It is an object of the present invention to provide compositions for use as inhibitors and/or thermal insulants in rocket motors which on burning do not emit unaccept-able amounts of smoke.
According to the present invention, a rocket motor has a propellant charge situated within, and incompletely filling a `~ motor casing, the space between the said propellant charge and the motor casing being at least partially filled by an elastomeric composition comprising a silicone elastomer having asbestos dis-persed therein~
According to one embodiment of the invention, the elastomeric composition is situated immediately adjacent the . .
yropellant charge to act as an inhibitiny coa-ting to ensure constant mass-rate burning.
According to a further embodiment of the invention the elastomeric composition is situated adjacent the motor casing '71~
and ~cts as a thermal insulant be-tween the propellant charge and the said casing.
According to a preferred embodiment of the invention, therefore, the elastomeric composition fills substantially the entire space between the motor casing and the propellant charge and acts as both a thermal insulant and an inhibiting coating.
In this preferred embodiment the thermal insulant and inhibi-ting coating may be applied separately to the motor casing and pro-pellant charge respectively before the rocket motor is assembled;
or a single continuous layer of silicone elastomer having asbestos dispersed therein may be cast in situ between the propellant charge and the motor casing and thereby form both the inhibi-ting coatin~ and the thermal insulant.
The propellant charge may be composed of any propellant system, but is preferably a double-base propellant sys~em contain-ing both nitro-cellulose and at least one nitrated polyhydric alcohol.
The silicone elas-tomer may be any of -the we]l known silicon based elastomer systems having the general formula ~0 ( n (4-n)/2)m wl~erein n is 0, 1, 2 or 3; m is greater than 2; and R represents an alkyl, aryl, fluoroalkyl, alkenyl, alkaryl or aralkyl group or a mixture of such groups with each other and/or with other groups such as hydrogen or chlorine atoms, alkoxy, aryloxy or alkylamino groups. The silicone elastomer may be formed from any of the well-known precursor systems such as acetoxy-terminated, acetic acid eliminating, one pot systems or hydride-terminated, systems. However for ease of application to the propellant charge and for safety, it is preferable to use a room-temperature ~ 7~
curing two part silicone rubber formed by condensing an organo-polysiloxane with an alkyl silicate ester according to an equation of the type ! R R aR 1 ~0-- si ---o ~ -- si , o~ -- y,o----- --~ o -l;Y -- xo ' s;i--- ------ X
R In R OR(or R~ ,R i n Ca-talys-t W
jR 1 fR
~o Lsi-~ o ~ . _ Si o --fi ---~ ----t---l i o l x R n R OR (orR) R ~n /
Eqn 1.
~herein X represents a hydrogen atom and Y an alkyl group. Alter-natively an organopolysiloxane ester wherein X represents an alkyl ~roup may be reacted with a hydroxy terminated polysiloxane.
The catalyst used may be, for example, a monocarboxylic
The in~ention relates to rocket motors, especially those employing double-base propellants, and to means or reducing the smoke emission therefrom. The expression rocket motor as used in this specirication re~ers to a casing vented a-t one end and containin~ a combus-tible propellant charge.
It is an essential feature of line-of-sight optically guided missiles that smoke emitted during flight must not obscure the missile or the target. In the case of military weapons, smoke is additionally undesirable since it assists an enemy in pin-pointing the launch area. Most double base propellant systemsare, in themselves, relatively smoke free, but even rocket motors employing such propellant system still produce unacceptable levels of smoke emission, a significant contribution being that from the inhibiting coating applied to the solid propellant to produce constant mass rate burning, and also the thermal insulant between the propellant charge and the motor casing.
The term "double-base prope].lant" as used herein refers to propellant systems containing both nitro-cellulose and a nitrated polyhydric alcohol, eg nitro-glycerine, tri-ethylene ~0 ~Jlycol dinitrate or di-ethylene glycol dinitrate. Composite modified double-base propellants containing ammonium perchlora-te produce e~haust containing hydrogen chloride which forms mist in moist air and hence such composite modified systems are not generally employed when a smoke-free system is required. How-ever, the present invention normally will reduce the smoke ernis-sion from the inhibiting coating and thermal insulation even in these systems.
Further, the invention is not limited to double-base systems, but may be employed to reduce the smoke emission from rocket motors employing any propellant system, althoucJh rnaximum beneflt will obviously be ob-tained when the propellant sys-tem itself is smoke-free or "low smo~e".
Currently used lnhibitors and -thermal insulants, for e~ample cellulose acetate and ethyl cellulose, both plasticised ~ith phthalate esters and "Hypalon" rubber~ (chlorosulphonated polyethylenes) give unacceptably large amounts of smoke and often show other undesirable properties such as high nit:roglycerine absorption or low softening temperature. Silicone elastomers ~0 have many desirable properties for use as inhibitors and/or thermal insulants such as low temperature flexibility, low nitro-glycerine absorption and high thermal stability, but when unfilled or filled with commercial fillers such as CaCo3 sio2 or Tio2 give copious smoke emission. It is an object of the present invention to provide compositions for use as inhibitors and/or thermal insulants in rocket motors which on burning do not emit unaccept-able amounts of smoke.
According to the present invention, a rocket motor has a propellant charge situated within, and incompletely filling a `~ motor casing, the space between the said propellant charge and the motor casing being at least partially filled by an elastomeric composition comprising a silicone elastomer having asbestos dis-persed therein~
According to one embodiment of the invention, the elastomeric composition is situated immediately adjacent the . .
yropellant charge to act as an inhibitiny coa-ting to ensure constant mass-rate burning.
According to a further embodiment of the invention the elastomeric composition is situated adjacent the motor casing '71~
and ~cts as a thermal insulant be-tween the propellant charge and the said casing.
According to a preferred embodiment of the invention, therefore, the elastomeric composition fills substantially the entire space between the motor casing and the propellant charge and acts as both a thermal insulant and an inhibiting coating.
In this preferred embodiment the thermal insulant and inhibi-ting coating may be applied separately to the motor casing and pro-pellant charge respectively before the rocket motor is assembled;
or a single continuous layer of silicone elastomer having asbestos dispersed therein may be cast in situ between the propellant charge and the motor casing and thereby form both the inhibi-ting coatin~ and the thermal insulant.
The propellant charge may be composed of any propellant system, but is preferably a double-base propellant sys~em contain-ing both nitro-cellulose and at least one nitrated polyhydric alcohol.
The silicone elas-tomer may be any of -the we]l known silicon based elastomer systems having the general formula ~0 ( n (4-n)/2)m wl~erein n is 0, 1, 2 or 3; m is greater than 2; and R represents an alkyl, aryl, fluoroalkyl, alkenyl, alkaryl or aralkyl group or a mixture of such groups with each other and/or with other groups such as hydrogen or chlorine atoms, alkoxy, aryloxy or alkylamino groups. The silicone elastomer may be formed from any of the well-known precursor systems such as acetoxy-terminated, acetic acid eliminating, one pot systems or hydride-terminated, systems. However for ease of application to the propellant charge and for safety, it is preferable to use a room-temperature ~ 7~
curing two part silicone rubber formed by condensing an organo-polysiloxane with an alkyl silicate ester according to an equation of the type ! R R aR 1 ~0-- si ---o ~ -- si , o~ -- y,o----- --~ o -l;Y -- xo ' s;i--- ------ X
R In R OR(or R~ ,R i n Ca-talys-t W
jR 1 fR
~o Lsi-~ o ~ . _ Si o --fi ---~ ----t---l i o l x R n R OR (orR) R ~n /
Eqn 1.
~herein X represents a hydrogen atom and Y an alkyl group. Alter-natively an organopolysiloxane ester wherein X represents an alkyl ~roup may be reacted with a hydroxy terminated polysiloxane.
The catalyst used may be, for example, a monocarboxylic
2~ acid salt of a metal such as tin or lead.
The term "asbestos" as used herein reEers to those in-combus~ible mineral silicates commonly known as asbestos which may vary in colour and may consist of simple silicates such as magne-sium silicate (chrysotile) or complex silicates such as magnesium iron silicates (amosite) or sodium iron silicates (crocidolite).
The asbestos may be in any physical form, for example as long fibres, mos-tly having a length of about 50 to 500 ~m and a breadth of about 5 ~lm, or as short fibres ("Elour") mostly having a lenqth of about S to 50 ~m and also a bread-th oE about 5 -to 50 ~m.
~referably, however, the asbestos is in the form oE long fibres havin~ an aspect ratio (length : breadth) of at least 10 : 1 since these give a ~reater reduction in smoke emission than shor-t fibres and also avoid puffs of smoke observed when sho~t fibres are usedO
Long fibres also give increased mechanical strength to the sili-cone elastomer composition. The asbestos should advan~ageously comprise at least 10~, preferably at least 20%, by weight of the composition. The upper limi~ of asbes-tos conten-t is set by -the ~ifficulty of blending high loadings of asbestos, especially long fibres, with the silicone elastomer to form a wor~able mixture.
~ith simple blending appara-tus the limit of workability is reached at about 25% w/w of long fibres or ~0% w/w of flour, bu-t with more efficient blending systems higher loadings may be reached.
The asbestos should be ad~ed to the mixture of the precursors of the elastomer before said precursors are cured. Thus the asbestos may, for example, be mixed with the organopolysiloxane and the alkyl silicate and catalyst added. The mixture is then applied to the area where thermal insulation is required or coated on to the surface of the propellant charge, preferably after painting _~ the said surface with a silane coupling agent composition, for example that comprising ~-glycidoxy propyl trimethoxy silane and an aromatic amine curing agent in a weight ratio of about 1:1 (as described by Stenson and Manners, 5th Int Congress of Surface Activity, 1968, pp ).
Examples illustrating the smoke emission from various inhibitors for double-base propellants will now be described with reference to the àccompanying drawings which illustrate the con-figurations of rocket motors used. All propellants used in -the examples were nitrocellulose/nitroglycerine double-base propellant containing various ballistic modifiers.
.
'7~:9%
~XAMPLE 1 Preliminary screening was carried ou-t using the arrange-ment shown in Figure ] wherein an uninhibited double-base pro-pellant 1 is burned at approximately 8 MN/m2 in a motor casing 2of diameter 51 mm and the exhaust directed through a tube 3 of ~iameter 51 mm having a lining 4 of a~out 5 mm thickness of the inhibitor being tested. The smoke emission after 1 second was estimated on an arbitrary scale 0 to 10. The results are shown in table I.
TABLE I
Particle %(w/w) of Inhibitor Filler % w/w of size ,um Smoke Emission inhibitor Filler of Filler eroded K96601'2 None o _ 8.7 22.4 " SlC 50 40 7.6 26.3 " MgO 50 40 8.0 21.3 " MgO 35 40 9.2 21.0 K9660 ' 2 3 50 40 7.6 20.5 " Alkon3 25 7.0 21.1 " Asbestos flour255 to 50 3.6 15.0 " " " 35 " 2.2 4.7 " " " 45 " 3.2 3.4 Asbestos flour 35 " 2.7 3.5 Boric acid 10 Cellulose5 Acetate ~ 4 23 Ethyl - - - 3 21 Cellulose Hypalon BaSO~ 60 - 4 7 O = zero smoke 10 = complete obscuration '7~
~OTES
1 K9660 is a polydimethylsiloxane/a1kyl silicate ester ~UM stock produc~ accor~ to equation 1 and Eorms -the basls of the filled material sold by Midland Sili-cones Ltd. under the sales no MS 9161.
2 Supplied by Midland Silicones Ltd.
The term "asbestos" as used herein reEers to those in-combus~ible mineral silicates commonly known as asbestos which may vary in colour and may consist of simple silicates such as magne-sium silicate (chrysotile) or complex silicates such as magnesium iron silicates (amosite) or sodium iron silicates (crocidolite).
The asbestos may be in any physical form, for example as long fibres, mos-tly having a length of about 50 to 500 ~m and a breadth of about 5 ~lm, or as short fibres ("Elour") mostly having a lenqth of about S to 50 ~m and also a bread-th oE about 5 -to 50 ~m.
~referably, however, the asbestos is in the form oE long fibres havin~ an aspect ratio (length : breadth) of at least 10 : 1 since these give a ~reater reduction in smoke emission than shor-t fibres and also avoid puffs of smoke observed when sho~t fibres are usedO
Long fibres also give increased mechanical strength to the sili-cone elastomer composition. The asbestos should advan~ageously comprise at least 10~, preferably at least 20%, by weight of the composition. The upper limi~ of asbes-tos conten-t is set by -the ~ifficulty of blending high loadings of asbestos, especially long fibres, with the silicone elastomer to form a wor~able mixture.
~ith simple blending appara-tus the limit of workability is reached at about 25% w/w of long fibres or ~0% w/w of flour, bu-t with more efficient blending systems higher loadings may be reached.
The asbestos should be ad~ed to the mixture of the precursors of the elastomer before said precursors are cured. Thus the asbestos may, for example, be mixed with the organopolysiloxane and the alkyl silicate and catalyst added. The mixture is then applied to the area where thermal insulation is required or coated on to the surface of the propellant charge, preferably after painting _~ the said surface with a silane coupling agent composition, for example that comprising ~-glycidoxy propyl trimethoxy silane and an aromatic amine curing agent in a weight ratio of about 1:1 (as described by Stenson and Manners, 5th Int Congress of Surface Activity, 1968, pp ).
Examples illustrating the smoke emission from various inhibitors for double-base propellants will now be described with reference to the àccompanying drawings which illustrate the con-figurations of rocket motors used. All propellants used in -the examples were nitrocellulose/nitroglycerine double-base propellant containing various ballistic modifiers.
.
'7~:9%
~XAMPLE 1 Preliminary screening was carried ou-t using the arrange-ment shown in Figure ] wherein an uninhibited double-base pro-pellant 1 is burned at approximately 8 MN/m2 in a motor casing 2of diameter 51 mm and the exhaust directed through a tube 3 of ~iameter 51 mm having a lining 4 of a~out 5 mm thickness of the inhibitor being tested. The smoke emission after 1 second was estimated on an arbitrary scale 0 to 10. The results are shown in table I.
TABLE I
Particle %(w/w) of Inhibitor Filler % w/w of size ,um Smoke Emission inhibitor Filler of Filler eroded K96601'2 None o _ 8.7 22.4 " SlC 50 40 7.6 26.3 " MgO 50 40 8.0 21.3 " MgO 35 40 9.2 21.0 K9660 ' 2 3 50 40 7.6 20.5 " Alkon3 25 7.0 21.1 " Asbestos flour255 to 50 3.6 15.0 " " " 35 " 2.2 4.7 " " " 45 " 3.2 3.4 Asbestos flour 35 " 2.7 3.5 Boric acid 10 Cellulose5 Acetate ~ 4 23 Ethyl - - - 3 21 Cellulose Hypalon BaSO~ 60 - 4 7 O = zero smoke 10 = complete obscuration '7~
~OTES
1 K9660 is a polydimethylsiloxane/a1kyl silicate ester ~UM stock produc~ accor~ to equation 1 and Eorms -the basls of the filled material sold by Midland Sili-cones Ltd. under the sales no MS 9161.
2 Supplied by Midland Silicones Ltd.
3 ~lkon is a polyoxymethylene copolymer, now sold by ICI
under the Registered Trade Mark "Kemetal".
~ Lenyth and breadth of particles each in -the range 5 to 50 ,um.
Plasticlsed with phthalate esters.
6 Hypalon CL d851, is a chlorosulphonated polyethylene cross-linked with lead oxide, PbO, supplied by the Northern Rubber Co.
E~A~IPLE 2 Tests on fibrous asbestos filled K9660 silicone elastomer were carried out in the flameless motor configuration shown in Figure 2 wherein a motor casing 11 contains only a short charge 12 of propellant, but the inhibitor coating 13 on the propellant extends over the whole length of the motor casing. This configuration gives a higher inhibitor to propellant ratio than would a full ch~rge system and involves passing exhaust over a considerable length of inhibitor coating even at the commencement of burning~
Hel~ce smoke emission would be expected to be worse wi-th -this system than with a full charge system, Tests were carried out using a cool propellant (chamber temp 2290K) and smoke emission was assessed on an arbitrary scale 0 to 10 after 5, 10, 15 and 20 seconds burning time under flameless conditions, The results are shown in Table II, .
~.~'7~
TABLE II
Smoke emission Inhibitor E'iller %w/w of Filler ( sec from iyni-tion) K 9660Asbestos fibrel 10 7.8 8.2 8.2 8.6 " " 20 2.8 2.8 2.1 3.0 "Asbestos flour 10 7 8 8 9 Cellulose acetate (phthalate ester plasticised) - - 8.7 8.9 8.2 7.6 1 Length 50 to 500 ~m, breadth about 5 ~m.
2 Length 5 to 50 ~m, breadth 5 to 50 ,um.
EX2~1PLE 3 Example 2 was repeated for asbestos flour and asbestos fibre filled silicone K9660 using a hotter propellant (chamber temperature 2620K) under flameless conditions. The results are shown in table III.
TABLE III
Length Preadth Smoke Emission Inhibitor Filler %w/w of Filler range range (sec from (jum) (jum) ignition) K 9660 Asbestos flour 20 5-505-50 2.2 5.1 3.0 9.9 " " " 25 5-50 5-501.7 8.0 2.7 9.4 " " " 30 5-50 5-501.7 2.4 4.4 8.8 " Asbestos fibre 25 50-500 about 51.5 1.5 2.6 5.6 ,, ' ' . ' ~ ' ~ '
under the Registered Trade Mark "Kemetal".
~ Lenyth and breadth of particles each in -the range 5 to 50 ,um.
Plasticlsed with phthalate esters.
6 Hypalon CL d851, is a chlorosulphonated polyethylene cross-linked with lead oxide, PbO, supplied by the Northern Rubber Co.
E~A~IPLE 2 Tests on fibrous asbestos filled K9660 silicone elastomer were carried out in the flameless motor configuration shown in Figure 2 wherein a motor casing 11 contains only a short charge 12 of propellant, but the inhibitor coating 13 on the propellant extends over the whole length of the motor casing. This configuration gives a higher inhibitor to propellant ratio than would a full ch~rge system and involves passing exhaust over a considerable length of inhibitor coating even at the commencement of burning~
Hel~ce smoke emission would be expected to be worse wi-th -this system than with a full charge system, Tests were carried out using a cool propellant (chamber temp 2290K) and smoke emission was assessed on an arbitrary scale 0 to 10 after 5, 10, 15 and 20 seconds burning time under flameless conditions, The results are shown in Table II, .
~.~'7~
TABLE II
Smoke emission Inhibitor E'iller %w/w of Filler ( sec from iyni-tion) K 9660Asbestos fibrel 10 7.8 8.2 8.2 8.6 " " 20 2.8 2.8 2.1 3.0 "Asbestos flour 10 7 8 8 9 Cellulose acetate (phthalate ester plasticised) - - 8.7 8.9 8.2 7.6 1 Length 50 to 500 ~m, breadth about 5 ~m.
2 Length 5 to 50 ~m, breadth 5 to 50 ,um.
EX2~1PLE 3 Example 2 was repeated for asbestos flour and asbestos fibre filled silicone K9660 using a hotter propellant (chamber temperature 2620K) under flameless conditions. The results are shown in table III.
TABLE III
Length Preadth Smoke Emission Inhibitor Filler %w/w of Filler range range (sec from (jum) (jum) ignition) K 9660 Asbestos flour 20 5-505-50 2.2 5.1 3.0 9.9 " " " 25 5-50 5-501.7 8.0 2.7 9.4 " " " 30 5-50 5-501.7 2.4 4.4 8.8 " Asbestos fibre 25 50-500 about 51.5 1.5 2.6 5.6 ,, ' ' . ' ~ ' ~ '
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A rocket motor having a propellant charge situated with-in and incompletely filling a motor casing to leave a space between said propellant charge and said motor casing, said space being at least partially filled by an elastomeric composition comprising a silicone elastomer having asbestos dispersed therein.
2. A rocket motor according to claim 1 wherein the elasto-meric composition is situated immediately adjacent the propellant charge to act as an inhibiting coating thereon.
3. A rocket motor according to claim 1 wherein the elasto-meric composition is situated adjacent the motor casing to act as a thermal insulant.
4. A rocket motor according to claim 1 wherein the elasto-meric composition fills substantially the entire space between the propellant charge and the motor casing and acts both as an inhibiting coating and as a thermal insulant.
5. A rocket motor according to any one of claims 2 to 4 wherein the silicone elastomer is produced by reacting an organo-polysiloxane with an alkyl silicate ester.
6. A rocket motor according to any one of claims 2 to 4 wherein the silicone elastomer is produced by reacting an organo-polysiloxane ester with an alkyl silicate.
7. A rocket motor according to any one of claims 2 to 4 wherein the asbestos is in the form of fibres having an aspect ratio of at least 10 : 1.
8. A rocket motor according to any one of claims 2 to 4 wherein the asbestos fibres have a length of 50 to 500 µm and a breadth of about 5 µm.
3. A rocket motor according to any one of claims 2 to 4 wherein the asbestos constitutes at least 10% by weight of the elastomeric composition.
10. A rocket motor according to any one of claims 2 to 4 wherein the asbestos constitutes at least 20% by weight of the elastomeric composition.
11. A rocket motor according to any one of claims 2 to 4 wherein the propellant charge comprises a double-base propellant containing nitrocellulose and a nitrated polyhydric alcohol.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB635772A GB1605210A (en) | 1972-02-10 | 1972-02-10 | Smokeless rocket motors |
| GB6357/72 | 1972-02-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1171292A true CA1171292A (en) | 1984-07-24 |
Family
ID=9813044
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000163326A Expired CA1171292A (en) | 1972-02-10 | 1973-02-09 | Propellants |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1171292A (en) |
| GB (1) | GB1605210A (en) |
-
1972
- 1972-02-10 GB GB635772A patent/GB1605210A/en not_active Expired
-
1973
- 1973-02-09 CA CA000163326A patent/CA1171292A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB1605210A (en) | 1983-11-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |