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What features enable the Su-25 Frogfoot to operate with such a wide variety of fuels?

Why do jet engines use kerosene rather than gasoline?Is it possible for an SU-25 to fly high enough to shoot down a Boeing 777?Can a Diesel Aircraft engine be run on Car Diesel?What fuels can turbofans burn?Can you safely operate a 777 with diesel?Are tripropellant jet engines a viable way to increase fuel efficiency for large commercial airplanes?Could most commercial jet engines today run on ethanol without any problems?What are the drawbacks of a liquid hydrogen jet engine?Does the USA government operate any business-jets with mid-air refueling capability?How does the Pratt & Whitney F119 achieve its features?What fuels can turbofans burn?Can you safely operate a 777 with diesel?Why does the Zapata Flyboard Air UL consume so much more fuel/hr than the Mosquito Air?How would a new “clean sheet” General Aviation piston engine with all the latest technology differ from existing Continental/Lycoming types?Could modern military aircraft be retrofitted to work with alternative fuels instead of kerosene?

11

$begingroup$

It is widely attested* that the Su-25 Frogfoot's engines (the Turmansky R-95Sh and later the R-195) were designed to function using a wide variety of fuels, including diesel, gasoline, petrol, kerosene and avgas.

For a rough-field front-line attack aircraft, the ability to load it with whatever was at hand, even tank fuel, would be very useful.

It's not a feature I've read about anywhere else. The question is, what specific engine modifications allow this level of fuel-tolerance in comparison with, for example, the T-34 which powers the A-10, an aircraft designed for a similar role.

 * for example miltaryfactory.com lowflying.net

Su-25 Grach (NATO reporting name: Frogfoot)

---

(Previous questions asked whether diesel engine aircraft can run on car diesel (yes) and if you could safely run a 777 on diesel (no).)

jet-engine military fuel engine-design

share|improve this question

asked 7 hours ago

Party ArkParty Ark

2,51311434

$endgroup$

add a comment | 

11

$begingroup$

It is widely attested* that the Su-25 Frogfoot's engines (the Turmansky R-95Sh and later the R-195) were designed to function using a wide variety of fuels, including diesel, gasoline, petrol, kerosene and avgas.

For a rough-field front-line attack aircraft, the ability to load it with whatever was at hand, even tank fuel, would be very useful.

It's not a feature I've read about anywhere else. The question is, what specific engine modifications allow this level of fuel-tolerance in comparison with, for example, the T-34 which powers the A-10, an aircraft designed for a similar role.

 * for example miltaryfactory.com lowflying.net

Su-25 Grach (NATO reporting name: Frogfoot)

---

(Previous questions asked whether diesel engine aircraft can run on car diesel (yes) and if you could safely run a 777 on diesel (no).)

jet-engine military fuel engine-design

share|improve this question

asked 7 hours ago

Party ArkParty Ark

2,51311434

$endgroup$

add a comment | 

$begingroup$

It is widely attested* that the Su-25 Frogfoot's engines (the Turmansky R-95Sh and later the R-195) were designed to function using a wide variety of fuels, including diesel, gasoline, petrol, kerosene and avgas.

For a rough-field front-line attack aircraft, the ability to load it with whatever was at hand, even tank fuel, would be very useful.

It's not a feature I've read about anywhere else. The question is, what specific engine modifications allow this level of fuel-tolerance in comparison with, for example, the T-34 which powers the A-10, an aircraft designed for a similar role.

 * for example miltaryfactory.com lowflying.net

Su-25 Grach (NATO reporting name: Frogfoot)

---

(Previous questions asked whether diesel engine aircraft can run on car diesel (yes) and if you could safely run a 777 on diesel (no).)

jet-engine military fuel engine-design

share|improve this question

asked 7 hours ago

Party ArkParty Ark

2,51311434

$endgroup$

share|improve this question

asked 7 hours ago

Party ArkParty Ark

2,51311434

share|improve this question

asked 7 hours ago

Party ArkParty Ark

2,51311434

asked 7 hours ago

Party ArkParty Ark

2,51311434

asked 7 hours ago

Party ArkParty Ark

2,51311434

1 Answer
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10

$begingroup$

Being a ground attack aircraft, the Su-25 has an operational ceiling of 23,000 ft and will not encounter the low temperatures to which a Boeing 777 is regularly exposed. Therefore, the risk of diesel fuel gelling and clogging the fuel lines is much lower.

On the other side of the temperature scale, gasoline could vaporize in hot environments and equally endanger the fuel supply of the engines. Those extremes are rarely found in the countries of the former Eastern Bloc, and the Su-25 was primarily designed for operations in moderate climates.

Nevertheless, some modifications are advised in order to avoid trouble when exotic fuels are used:

• Regular fuel pumps use kerosene for lubrication. Kerosene is a good lubricant and allows for a simpler pump design. By using better bearings, the fuel pump can also be used with gasoline or petrol without suffering long-term damage.


• Running the fuel lines away from hot surfaces reduces the risk of vapour bubbles forming inside. I don't know the details of the Su-25 design, but I would be mightily surprised if any fuel line runs right below the upper skin of the aircraft where the sun can heat the surface to temperatures in excess of 70° even in moderate latitudes. This is supported by a light grey paint scheme as shown by the Ukrainian Su-25 in your question.


• Don't do fancy things with the fuel, like use it as a hydraulic fluid, but restrict its use to being burned in the engine. Then any liquid hydrocarbon can be used.

That turbofans can run on a wide variety of fuels has been established in the answers to this question.

share|improve this answer

edited 6 hours ago

answered 6 hours ago

Peter KämpfPeter Kämpf

160k12405650

$endgroup$

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  $begingroup$
  Another factor: military engines aren't made to last very long. This article says TBO is 750-1500 FH. You can just let the pumps and components wear.
  $endgroup$
  – user71659
  3 hours ago
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  $begingroup$
  @user71659: That is typical for Russian engines, but does not indicate their fragility but the desire of Soviet planners to keep engine mechanics employed. When the West German airforce looked into the East German MiG-29s after reunification, they found that the engines would safely last for almost three times the scheduled hours. The An-70 is designed to last for 6 months without any maintenance (but after that time it is really worn out).
  $endgroup$
  – Peter Kämpf
  2 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I suspect that you mean 70°C, but it would be great if you clarified.
  $endgroup$
  – chrylis
  2 hours ago
  

  
  
  
  

add a comment | 

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10

$begingroup$

Being a ground attack aircraft, the Su-25 has an operational ceiling of 23,000 ft and will not encounter the low temperatures to which a Boeing 777 is regularly exposed. Therefore, the risk of diesel fuel gelling and clogging the fuel lines is much lower.

On the other side of the temperature scale, gasoline could vaporize in hot environments and equally endanger the fuel supply of the engines. Those extremes are rarely found in the countries of the former Eastern Bloc, and the Su-25 was primarily designed for operations in moderate climates.

Nevertheless, some modifications are advised in order to avoid trouble when exotic fuels are used:

• Regular fuel pumps use kerosene for lubrication. Kerosene is a good lubricant and allows for a simpler pump design. By using better bearings, the fuel pump can also be used with gasoline or petrol without suffering long-term damage.


• Running the fuel lines away from hot surfaces reduces the risk of vapour bubbles forming inside. I don't know the details of the Su-25 design, but I would be mightily surprised if any fuel line runs right below the upper skin of the aircraft where the sun can heat the surface to temperatures in excess of 70° even in moderate latitudes. This is supported by a light grey paint scheme as shown by the Ukrainian Su-25 in your question.


• Don't do fancy things with the fuel, like use it as a hydraulic fluid, but restrict its use to being burned in the engine. Then any liquid hydrocarbon can be used.

That turbofans can run on a wide variety of fuels has been established in the answers to this question.

share|improve this answer

edited 6 hours ago

answered 6 hours ago

Peter KämpfPeter Kämpf

160k12405650

$endgroup$

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  $begingroup$
  Another factor: military engines aren't made to last very long. This article says TBO is 750-1500 FH. You can just let the pumps and components wear.
  $endgroup$
  – user71659
  3 hours ago
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  $begingroup$
  @user71659: That is typical for Russian engines, but does not indicate their fragility but the desire of Soviet planners to keep engine mechanics employed. When the West German airforce looked into the East German MiG-29s after reunification, they found that the engines would safely last for almost three times the scheduled hours. The An-70 is designed to last for 6 months without any maintenance (but after that time it is really worn out).
  $endgroup$
  – Peter Kämpf
  2 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I suspect that you mean 70°C, but it would be great if you clarified.
  $endgroup$
  – chrylis
  2 hours ago
  

  
  
  
  

add a comment | 

10

$begingroup$

Being a ground attack aircraft, the Su-25 has an operational ceiling of 23,000 ft and will not encounter the low temperatures to which a Boeing 777 is regularly exposed. Therefore, the risk of diesel fuel gelling and clogging the fuel lines is much lower.

On the other side of the temperature scale, gasoline could vaporize in hot environments and equally endanger the fuel supply of the engines. Those extremes are rarely found in the countries of the former Eastern Bloc, and the Su-25 was primarily designed for operations in moderate climates.

Nevertheless, some modifications are advised in order to avoid trouble when exotic fuels are used:

• Regular fuel pumps use kerosene for lubrication. Kerosene is a good lubricant and allows for a simpler pump design. By using better bearings, the fuel pump can also be used with gasoline or petrol without suffering long-term damage.


• Running the fuel lines away from hot surfaces reduces the risk of vapour bubbles forming inside. I don't know the details of the Su-25 design, but I would be mightily surprised if any fuel line runs right below the upper skin of the aircraft where the sun can heat the surface to temperatures in excess of 70° even in moderate latitudes. This is supported by a light grey paint scheme as shown by the Ukrainian Su-25 in your question.


• Don't do fancy things with the fuel, like use it as a hydraulic fluid, but restrict its use to being burned in the engine. Then any liquid hydrocarbon can be used.

That turbofans can run on a wide variety of fuels has been established in the answers to this question.

share|improve this answer

edited 6 hours ago

answered 6 hours ago

Peter KämpfPeter Kämpf

160k12405650

$endgroup$

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  $begingroup$
  Another factor: military engines aren't made to last very long. This article says TBO is 750-1500 FH. You can just let the pumps and components wear.
  $endgroup$
  – user71659
  3 hours ago
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  $begingroup$
  @user71659: That is typical for Russian engines, but does not indicate their fragility but the desire of Soviet planners to keep engine mechanics employed. When the West German airforce looked into the East German MiG-29s after reunification, they found that the engines would safely last for almost three times the scheduled hours. The An-70 is designed to last for 6 months without any maintenance (but after that time it is really worn out).
  $endgroup$
  – Peter Kämpf
  2 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I suspect that you mean 70°C, but it would be great if you clarified.
  $endgroup$
  – chrylis
  2 hours ago
  

  
  
  
  

add a comment | 

$begingroup$

Being a ground attack aircraft, the Su-25 has an operational ceiling of 23,000 ft and will not encounter the low temperatures to which a Boeing 777 is regularly exposed. Therefore, the risk of diesel fuel gelling and clogging the fuel lines is much lower.

On the other side of the temperature scale, gasoline could vaporize in hot environments and equally endanger the fuel supply of the engines. Those extremes are rarely found in the countries of the former Eastern Bloc, and the Su-25 was primarily designed for operations in moderate climates.

Nevertheless, some modifications are advised in order to avoid trouble when exotic fuels are used:

• Regular fuel pumps use kerosene for lubrication. Kerosene is a good lubricant and allows for a simpler pump design. By using better bearings, the fuel pump can also be used with gasoline or petrol without suffering long-term damage.


• Running the fuel lines away from hot surfaces reduces the risk of vapour bubbles forming inside. I don't know the details of the Su-25 design, but I would be mightily surprised if any fuel line runs right below the upper skin of the aircraft where the sun can heat the surface to temperatures in excess of 70° even in moderate latitudes. This is supported by a light grey paint scheme as shown by the Ukrainian Su-25 in your question.


• Don't do fancy things with the fuel, like use it as a hydraulic fluid, but restrict its use to being burned in the engine. Then any liquid hydrocarbon can be used.

That turbofans can run on a wide variety of fuels has been established in the answers to this question.

share|improve this answer

edited 6 hours ago

answered 6 hours ago

Peter KämpfPeter Kämpf

160k12405650

$endgroup$

share|improve this answer

edited 6 hours ago

answered 6 hours ago

Peter KämpfPeter Kämpf

160k12405650

answered 6 hours ago

Peter KämpfPeter Kämpf

160k12405650

answered 6 hours ago

Peter KämpfPeter Kämpf

160k12405650