By: franc
- 11th June 2008 at 05:22Permalink- Edited 1st January 1970 at 01:00
Read my post where I showed turbojet SFC versus turbofan SFC. Don't get trapped by static data, they tell you nothing. For cruise conditions the TJ's SFC is about 20 to 40% higher.
This vague predict didn't overthrow the precious data MiG given.
1/10 is inverse glide ratio and means that for for 10t of lift you get 1t of drag. A glide ratio of 5 means 2t of drag for 10t of lift. Not that difficult.
Your comprehension for the L/D ratio still is wrong. Please review the knowledge you learnd.
Sukhoi gives away: Ferry flight range with 2xPTB-3000 external fuel tanks, km:
- with PTB external fuel tanks dropped 2,775
That is a high-up profile with no weapons.
That max possible range range without air-refuelling.
Stay at low level with Tj and a modest weapon-load that range do drop to 45 % of that high-up profile.
2775 km 45% of that is ~1250 km, which does does correspondent with the data of Sukhoi:
Operational radius of action at sea level in mixed mode (Vcr in the 200-km area, V=900 km/h in other areas) with PTB external fuel tanks and 6x FAB -500M-62 bombs, km 615
The ferry flights range data for the F-111 are high up profile too, without weapon-load.
At low level the F-111 can bring its advantages of Tf in play really, because the range do drop to 55-60% only related to load-conditions, when compared to high-up profile. With the same weapons-load a F-111 can go ~2500 km.
The EFT dropped didn't change anything we are discussing, no matter how many EFTs you carried, they would dropped already when you reach close to 50% range, because they've been emptied.
By: Schorsch
- 11th June 2008 at 08:09Permalink- Edited 1st January 1970 at 01:00
This vague predict didn't overthrow the precious data MiG given.
MiG has no idea and continues to quote over and over the same figues again. If you stick to it, do so, it will leave you with all the other laymen guessing around and assuming things that constitute this thread, but are ultimately wrong.
Your comprehension for the L/D ratio still is wrong. Please review the knowledge you learnd.
I earn my money with correct comprehension and application of L/D.
You may take a sheet of paper and try to re-enact the calculations I did with simple numbers.
You may Google the Breguet Range Equation.
Otherwise, stop simulating you have any understanding of basic aircraft performance figures.
I see you are not willing to understand.
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By: Jon James
- 11th June 2008 at 09:21Permalink- Edited 1st January 1970 at 01:00
I think this pic might apply here...
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By: MiG-23MLD
- 11th June 2008 at 09:52Permalink- Edited 1st January 1970 at 01:00
MiG has no idea and continues to quote over and over the same figues again. If you stick to it, do so, it will leave you with all the other laymen guessing around and assuming things that constitute this thread, but are ultimately wrong.
I earn my money with correct comprehension and application of L/D.
You may take a sheet of paper and try to re-enact the calculations I did with simple numbers.
You may Google the Breguet Range Equation.
Otherwise, stop simulating you have any understanding of basic aircraft performance figures.
I see you are not willing to understand.
Schorsch
You are an engineer no one denies that, i am not denying you might be a very good engineer, some one with experience and knowledge, however your data does not show the F-111 has a very big advantage in range due to SFC and lift/drag ratio.
you act even childish, i am open to learn as probably the vast majority of members are, but when i see the F-111 carries more than 28000 liters of fuel and the Su-24 only 19000 liters and i see a difference in range of 3165 miles (5000km) versus the 3050km of range the Su-24 has i do not see any miracle of aerodynamics as you claim.
All the data you claim does not prove at all the F-111 has a big advantage, see that only on internal fuel the F-111 carries the same fuel capacity the Su-24 has with three fuel tanks at ferry range.
you are not ignoring me, you are simply not facing those facts, you are ignoring and not even acknowledging a reality, the Su-24 carries less fuel than the F-111A in fact 8000 liters of fuel less when they fly their ferry range.
while you do not tackle those figures and acknowledge a reality that the F-111 carries more fuel at any configuration you are just barking but not biting.
therefore independently if you are a good engineer or not i think you are just boasting and not proving your facts with data taken from Sukhoi or the RAAF, since already at 51000kg the F-111 will be carring all its internal fuel and 11000kg or more of fuel tanks or weapons, around 30000kg rested from the empty weight of the F-111
also consider the F-111 has several variants and the Australian variant which is claimed to have a range of 5777km of range is the heaviest comparable only to the FB-111, the F-111A was lighter and has a shorter ferry range of 5093km
By: Schorsch
- 11th June 2008 at 10:41Permalink- Edited 1st January 1970 at 01:00
you are not ignoring me, you are simply not facing those facts, you are ignoring and not even acknowledging a reality,
I have all facts on the table and the results are very well documented in the published figures by Sukhoi for its own aircraft and for the F-111. They fit to the applied technology and make sense, when one understands it.
That is the factual situation.
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By: MiG-23MLD
- 11th June 2008 at 11:44Permalink- Edited 1st January 1970 at 01:00
I have all facts on the table and the results are very well documented in the published figures by Sukhoi for its own aircraft and for the F-111. They fit to the applied technology and make sense, when one understands it.
That is the factual situation.
Schorsch for me, you are just bluffing, to say you have all the data is like saying you have the manual of the Su-24 and F-111 at the same time, i do have three books about the F-111 and four about the Su-24 plus what i have read in the Sukhoi and RAAF webpages
You are just avoiding several questions.
A)what are the different ferry ranges for the FB-111, F-111A, F-111C and F-111F?
B)If the Su-24 flies with the same fuel an F-111 has at ferry range what would be the ferry range for the Su-24?
I have seen differences in weight between the F-111s variants ranging from 45000kg, 40000kg and 51000kg, also different ferry ranges quoted from more than 4700km to 5777km.
this ferry ranges also change with the variant becuase the FB-111 was a longer range bomber and the F-111C used by the Australian air force weighs the same.
All of this makes me to conclude the F-111A`s quoted range of 5090km and 45000kg weight with a 28000 liters fuel capacity is the average F-111 variant, if the Su-24 would have the same fuel carring capability of 28000 liters the Su-24 would have a range of 4400km or a Sukhoi quote range with one refueling of 5000km.
So i do not think the FB-111 has the same fuel capacity because the lighter EF-111 has a shorter range due to more electronic equipment.
In few words i do not think you are calculating your data realistically
By: Sens
- 11th June 2008 at 12:31Permalink- Edited 1st January 1970 at 01:00
You are wrong the Su-24 achieves the range of 2775km with two tanks not three, see Sukhoi`s webpage it says two fuel tanks that is not 15000kgs but much less, with three fuel tanks it will achieve 3000km, the F-111 when it flies more than 5000km (3165miles) is carrying six fuel tanks twice the number of the Su-24 can carry and more internal fuel, see the max take off given by the Royal Australian air force is 51000kg see this fact
Why the White Paper paradigm is centred upon the F-111 is simple - it carries 34,000 lb of internal fuel, thus making it a frugal consumer of aerial refuelling resources inside a 1,000 NMI radius of Australian continental runways.
already the internal fuel of the F-111 surpasses the fuel capacity of the Su-24 and 1000mn is well within the range of 2775km ferry range for the Su-24
in fact the F-111 carries 19112 liters of internal fuel alone
Combat radius was 1330 miles, with ferry range being 3165 miles with maximum external fuel being carried. Internal fuel capacity was 5043 US gallons. With underwing fuel tanks, a maximum of 7443 US gallons of fuel could be carried
while the Su-224 carries that amount with three fuel tanks
Общая эксплуатационная емкость внутренних баков составляет 11860 литров (у самолетов до N 8-11 с неувеличенным 1-м баком - 11200 литров). Запас топлива может быть увеличен с помощью двух подкрыльевых подвесных баков емкостью по 3000 литров (ПТБ-3000) и одного подфюзеляжного подвесного бака емкостью 2000 литров (ПТБ-2000). При подвеске трех баков суммарный запас топлива доводится до 19860 л.
The overall operational fuel capacity is 11860 litres with internal fuel tanks ( the planes before 8-11 series aircraft with no Enlarged 1 - m tank - had a mx internal fuel capacity of 11200 litres). Fuel can be increased by means of two external fuel tanks with capacity of 3000 litres (PTB-3000) and one ventral suspended tank capacity of 2000 litres (PTB-2000). In total suspension of three fuel tanks brought to 19860 litres.
so if the Su-24 carries 19860 liters and the relation fuel kg is 0.75:1 you get a total fuel capacity of only 14895 kg since Топливо
внутренние топливо, кг 9800
внутренние топливо, л 13000
where in kg the total internal fuel is 9800kg and in liters is 13000
In fact at max fuel the F-111A carries a max of 28281 liters in internal and external tanks or almost more than 8000 liters that the 19860 liters carried by the Su-24 in internal and external fuel tanks or slightly more than 1/3 of extra fuel, in fact if you calculate the relation fuel range the relation is like this 5000km/3000km=1.6 and 28000liters/19000liters= 1.4, you find the SFC of the AL-21 is just slightly higher than that of the TF-30
You are not afraid to cheat the people!
Data from Sukhoi: [conserative 0,78 kg density per litre]
14230 l intern + 8000 l extern = 22230 l for 3000 km or 7,41 l per km
Your data for the F-111A
28281 l total (intern+extern)for 5000 km or 5,66 l per km
When the lower value of 5,66 is the basic 100%, 7,41 is 130,9 % of that.
By the way, a number I did quote before.
All that high up, when the Tj is at its best.
But we discussed about the low-level range, where the Tf is at its best.
Even under best conditions high up the Su-24 is over 30% worse for every litre burned.
At low level the Su-24 is up to 100% worse.
The example does show for everyone to see. High up the Su-24 generates over 30% less range from every litre of fuel and when down on the deck it is even more worse.
For the other, it is not my intention to bash the producer of the Su-24, which were limited to that Tj-engine at hand. One of the best available Tj than, but still the wrong engine for a low level striker, which is in need of a Tf.
Just to bust that cloud of disinformation, by rising different numbers to proof nothing by that.
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By: MiG-23MLD
- 11th June 2008 at 12:57Permalink- Edited 1st January 1970 at 01:00
You are not afraid to cheat the people!
Data from Sukhoi: [conserative 0,78 kg density per litre]
14230 l intern + 8000 l extern = 22230 l for 3000 km or 7,41 l per km
Your data for the F-111A
28281 l total (intern+extern)for 5000 km or 5,66 l per km
When the lower value of 5,66 is the basic 100%, 7,41 is 130,9 % of that.
By the way, a number I did quote before.
All that high up, when the Tj is at its best.
But we discussed about the low-level range, where the Tf is at its best.
Even under best conditions high up the Su-24 is over 30% worse for every litre burned.
At low level the Su-24 is up to 100% worse.
The example does show for everyone to see. High up the Su-24 generates over 30% less range from every litre of fuel and when down on the deck it is even more worse.
For the other, it is not my intention to bash the producer of the Su-24, which were limited to that Tj-engine at hand. One of the best available Tj than, but still the wrong engine for a low level striker, which is in need of a Tf.
Just to bust that cloud of disinformation, by rising different numbers to proof nothing by that.
You are correct the Sukhoi webpage gives a higher internal fuel capacity for the Su-24Mk than the one AIRWAR ru uses, so my calculations did not consider that fact, i have been corrected.
Any way we have settled the issue, the Su-24MK carries more fuel that the one i quoted since airwar ru gives 9000kg and a total of 19000liters, however Sukhoi gives a higher internal fuel capability of 11100kg.
By: franc
- 11th June 2008 at 13:39Permalink- Edited 1st January 1970 at 01:00
Schorsch:
All the data you claim does not prove at all the F-111 has a big advantage, see that only on internal fuel the F-111 carries the same fuel capacity the Su-24 has with three fuel tanks at ferry range.
not three, two.
you are not ignoring me, you are simply not facing those facts, you are ignoring and not even acknowledging a reality, the Su-24 carries less fuel than the F-111A in fact 8000 liters of fuel less when they fly their ferry range.
By: franc
- 11th June 2008 at 14:41Permalink- Edited 1st January 1970 at 01:00
Let's keep them simply, unified all of units to liter.
2271 liters is the capacity of each external fuel tank F-111 could carry.
19112 liters is the internal fuel capacity F-111 carried
11883 liters is the internal fuel capacity carried by Su-24
3000 liters is the capacity that each external fuel tanks under wing glove of Su-24 contains
so we have those data fella:
Su-24 had internal fuel + external fuel = 11883 + 3000 * 2 = 17883 liters
F-111 got merely internal fuel 19112 liters, which still be greater than 17883 to 19112-17883=1229liters (about900-950kg)
please pay attetion to such little 1229 liters fuel won't cause so many gap of range between F-111 and Su-24, if the fuel consumption of engines these two jets fitted are similar. Noticed we had the 0.8 of Aardvark vs 0.76 of Fencer or 0.67 of Aardvark vs 0.76 of Fencer.
If all of other conditions are same, then 1229/19112, we got 0.064 which means, the F-111's range will only be longer than Su-24 6.4%.
If the SFC of engine F-111 used is 0.8, then [0.8-0.76]/0.8=0.05=5%, this will almost counteract the most of 6.4% longer range F-111 originally had. But if we used 0.67, then the advantage of range F-111 gained will be enlarged to 12%+6.4%=18.4%
The 18.4% is very much closer to the real gap of range 23%. The 23% come from [4700km -3600km]/4700km, if you insist the range of F-111 merely with internal fuel is 4700km. Where the rest 4.6% goes? I give it to the drag Su-24's external fuel tanks brought. If you guys insist the range of F-111 will be 5777km, I would also like to accept this data, then we will get 36.8% of advantage. 36.8-18.4=18.4 which will satisfied somebody who insist the drag coefficient external fuel tanks brought will be 20%. I think 18.4% is more reasonable for the EFT's drag coefficient.
Now we've done, each aspect can accept. The range of Su-24 even with two EFTs only reach 2/3 of F-111 can do with internal fuel only.
If we presumed both F-111 and Su-24 without external fuel tank, then 2775km range of Su-24 is reliable, so under this condition, then range of Su-24 will be only half range of F-111. 1/3 will be absolutely unacceptable.
By: Schorsch
- 11th June 2008 at 15:55Permalink- Edited 1st January 1970 at 01:00
Noticed we had the 0.8 of Aardvark vs 0.76 of Fencer or 0.67 of Aardvark vs 0.76 of Fencer.
These SFCs are wrong.
We have actual data for TF30-P-412 (see my post page 2) and can see that for max military at 11km and M0.9 the SFC is about 0.9;
we use as representative for the AL-21 the data for the R-35 from the MiG-23ML aerodynamic manual. Page 76 and 78 give us about 1.13 for such conditions.
Now: (1.13-0.9)/0.9 = 25.5% more SFC.
Note: both infos are from Russian sources, downloadable from the net.
Using Breguet range equation:
[ATTACH]162843[/ATTACH]
W_initial is TOW.
W_final is TOW - Fuel
We assume a reserve fuel of 1000kg.
Fuel density is 0.8kg/l.
And for God's sake, we assume both aircraft to weight 22t operating empty and similar L/Ds.
[ATTACH]162844[/ATTACH]
Hence: The SFC alone yields a 33% range penalty.
Now drop in the extra drag through external tanks and you easily arrive at the given figures from the quoted websites.
2839nm equal 5230km.
Note: for 0km altitude the SFC difference is similar, about 25%.
By: franc
- 11th June 2008 at 17:02Permalink- Edited 1st January 1970 at 01:00
Sens won't like the result you given, absolutely
:D:p:diablo:
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By: MiG-23MLD
- 11th June 2008 at 17:38Permalink- Edited 1st January 1970 at 01:00
Let's keep them simply, unified all of units to liter.
2271 liters is the capacity of each external fuel tank F-111 could carry.
19112 liters is the internal fuel capacity F-111 carried
11883 liters is the internal fuel capacity carried by Su-24
3000 liters is the capacity that each external fuel tanks under wing glove of Su-24 contains
so we have those data fella:
Su-24 had internal fuel + external fuel = 11883 + 3000 * 2 = 17883 liters
F-111 got merely internal fuel 19112 liters, which still be greater than 17883 to 19112-17883=1229liters (about900-950kg)
please pay attetion to such little 1229 liters fuel won't cause so many gap of range between F-111 and Su-24, if the fuel consumption of engines these two jets fitted are similar. Noticed we had the 0.8 of Aardvark vs 0.76 of Fencer or 0.67 of Aardvark vs 0.76 of Fencer.
If all of other conditions are same, then 1229/19112, we got 0.064 which means, the F-111's range will only be longer than Su-24 6.4%.
If the SFC of engine F-111 used is 0.8, then [0.8-0.76]/0.8=0.05=5%, this will almost counteract the most of 6.4% longer range F-111 originally had. But if we used 0.67, then the advantage of range F-111 gained will be enlarged to 12%+6.4%=18.4%
The 18.4% is very much closer to the real gap of range 23%. The 23% come from [4700km -3600km]/4700km, if you insist the range of F-111 merely with internal fuel is 4700km. Where the rest 4.6% goes? I give it to the drag Su-24's external fuel tanks brought. If you guys insist the range of F-111 will be 5777km, I would also like to accept this data, then we will get 36.8% of advantage. 36.8-18.4=18.4 which will satisfied somebody who insist the drag coefficient external fuel tanks brought will be 20%. I think 18.4% is more reasonable for the EFT's drag coefficient.
Now we've done, each aspect can accept. The range of Su-24 even with two EFTs only reach 2/3 of F-111 can do with internal fuel only.
If we presumed both F-111 and Su-24 without external fuel tank, then 2775km range of Su-24 is reliable, so under this condition, then range of Su-24 will be only half range of F-111. 1/3 will be absolutely unacceptable.
Franc
I will be absolutedly honest with you, sukhoi qoutes a max internal fuel capacity of 11100kg see
Максимальный запас топлива во внутренних баках, кг 11100
Maximum internal fuel, kg 11,100
they do not mention how many liters it really carries internally a guessing as Sens said is close to 14000 liters, the Su-24 can carry three fuel tanks, however Sukhoi quotes a ferry range with only two fuel tanks Ferry flight range with 2xPTB-3000 external fuel tanks, km:
- with PTB external fuel tanks dropped 2,775
however Airbase.ru goes along with Sukhoi a quotes a fuel weight of 16000kg
Массы и нагрузки
Су-24 Су-24М
Масса, кг пустого 22320 22300
топлива 16440 16440
максимальная взлётная 39700
http://airbase.ru/hangar/planes/russia/su/su-24/
However i have read also that the Russians were aware of the fact the F-111 has a much longer range but this was unimportant since the Russians had a different military doctrine.
in my opinion the Su-24 might have an engine with a real SFC of 0.76 as quoted by the russian sources however its lift and LD ratio limit the aircraft and it uses the engines in different ways the F-111 does, and as sadly it might sound for a fan of the Su-24 like i am it is true what Sens and Schorsch are saying, the general performance of the Su-24 makes it spend much more fuel.
In fact i just read that the Russians were aware of that short coming of the Su-24 and they wanted to build the Su-24MM with an AL-31 however the inlets were so narrow and they did not allow enough air for the engine
Но АЛ-31Ф отличался намного большим расходом воздуха через компрессор, и для них пришлось сделать третий воздухозаборник над фюзеляжем, выглядевший довольно необычно. За это Су-24ММ на фирме получил прозвище "мертворожденный монстр", которое оказалось пророческим - вскоре и эта программа была прекращена. На этот раз в пользу ударных модификаций одного из самых удачных самолетов ОКБ - Су-27. But the AL-31F differed too much and had a larger flow of air through the compressor, and they had to make a third airlet over the fuselage, which looked quite unusual. For this, Su-24MM at the firm received the nickname "still-born monster", which proved prophetic - and soon the programme was discontinued in favor of a modification one of the most successful aircraft Su-27 (the SU-27IB). http://www.airwar.ru/enc/bomber/su24m.html
By: Schorsch
- 11th June 2008 at 18:08Permalink- Edited 1st January 1970 at 01:00
Sens won't like the result you given, absolutely
My results basically support each statement he did. I didn't plug in realistic weight data and used the fuel capacities you used. Including the effect of drop tanks would make the case even less desirable for the Suchoi 24.
Making a real missions assessment something that clearly exceeds the limit of what you do for an internet forum where many of the people not get the concept of SFC or L/D.
By: franc
- 11th June 2008 at 20:04Permalink- Edited 1st January 1970 at 01:00
MiG, I'd prefer accept the result Schorsch given. The final data s/he given was more closer to my opnion and reach the reality much more. I can't see why it is impossible that the range of Su-24 by internal fuel only is 75% of Aardvark.
By: Sens
- 11th June 2008 at 20:18Permalink- Edited 1st January 1970 at 01:00
MiG, I'd prefer accept the result Schorsch given. The final data s/he given was more closer to my opnion and reach the reality much more. I can't see why it is impossible that the range of Su-24 by internal fuel only is 75% of Aardvark.
Such a claim is called split identity or my understanding of English is very bad.
By: Sens
- 11th June 2008 at 20:47Permalink- Edited 1st January 1970 at 01:00
These SFCs are wrong.
We have actual data for TF30-P-412 (see my post page 2) and can see that for max military at 11km and M0.9 the SFC is about 0.9;
we use as representative for the AL-21 the data for the R-35 from the MiG-23ML aerodynamic manual. Page 76 and 78 give us about 1.13 for such conditions.
Now: (1.13-0.9)/0.9 = 25.5% more SFC.
Note: both infos are from Russian sources, downloadable from the net.
Using Breguet range equation:
[ATTACH]162843[/ATTACH]
W_initial is TOW.
W_final is TOW - Fuel
We assume a reserve fuel of 1000kg.
Fuel density is 0.8kg/l.
And for God's sake, we assume both aircraft to weight 22t operating empty and similar L/Ds.
[ATTACH]162844[/ATTACH]
Hence: The SFC alone yields a 33% range penalty.
Now drop in the extra drag through external tanks and you easily arrive at the given figures from the quoted websites.
2839nm equal 5230km.
Note: for 0km altitude the SFC difference is similar, about 25%.
Hi Schorsch,
three small details: The TF30-P-100 and P-414 are different and tuned for different missions as are the AL-21 and R-35 too. Even with two ETs dropped empty, Sukhoi do not claim more the 2775 km ferry range. The option of a third ET brings around 3000 km ferry range.
By: Schorsch
- 11th June 2008 at 22:04Permalink- Edited 1st January 1970 at 01:00
Hi Schorsch,
three small details: The TF30-P-100 and P-414 are different and tuned for different missions as are the AL-21 and R-35 too. Even with two ETs dropped empty, Sukhoi do not claim more the 2775 km ferry range. The option of a third ET brings around 3000 km ferry range.
That is accepted. But as I don't have SFC available for each engine in the world they set a useful yardstick to explain our fellows here the basics of aircraft engine design & performance. The data I gave can be considered representative for late 1960s engine design.
My little example was primarily aimed at showing the impact of a 25% higher SFC on overall range. If we plug in the correct weight data, assume the penalties for external tanks (and when they are dropped) and assess the rather tricky change of L/D for a swing wing aircraft (a ferry flight would most likely be done with wings swept fully forward, while a mission is mostly flown with wings in middle position). Then we also have to assume partial power SFC and flight profile.
However, no matter you turn it, the odds against the Suchoi 24 when it comes to range will not go away.
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By: franc - 11th June 2008 at 05:22 Permalink - Edited 1st January 1970 at 01:00
This vague predict didn't overthrow the precious data MiG given.
Your comprehension for the L/D ratio still is wrong. Please review the knowledge you learnd.
The EFT dropped didn't change anything we are discussing, no matter how many EFTs you carried, they would dropped already when you reach close to 50% range, because they've been emptied.
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By: Schorsch - 11th June 2008 at 08:09 Permalink - Edited 1st January 1970 at 01:00
MiG has no idea and continues to quote over and over the same figues again. If you stick to it, do so, it will leave you with all the other laymen guessing around and assuming things that constitute this thread, but are ultimately wrong.
I earn my money with correct comprehension and application of L/D.
You may take a sheet of paper and try to re-enact the calculations I did with simple numbers.
You may Google the Breguet Range Equation.
Otherwise, stop simulating you have any understanding of basic aircraft performance figures.
I see you are not willing to understand.
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By: Jon James - 11th June 2008 at 09:21 Permalink - Edited 1st January 1970 at 01:00
I think this pic might apply here...
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By: MiG-23MLD - 11th June 2008 at 09:52 Permalink - Edited 1st January 1970 at 01:00
Schorsch
You are an engineer no one denies that, i am not denying you might be a very good engineer, some one with experience and knowledge, however your data does not show the F-111 has a very big advantage in range due to SFC and lift/drag ratio.
you act even childish, i am open to learn as probably the vast majority of members are, but when i see the F-111 carries more than 28000 liters of fuel and the Su-24 only 19000 liters and i see a difference in range of 3165 miles (5000km) versus the 3050km of range the Su-24 has i do not see any miracle of aerodynamics as you claim.
All the data you claim does not prove at all the F-111 has a big advantage, see that only on internal fuel the F-111 carries the same fuel capacity the Su-24 has with three fuel tanks at ferry range.
you are not ignoring me, you are simply not facing those facts, you are ignoring and not even acknowledging a reality, the Su-24 carries less fuel than the F-111A in fact 8000 liters of fuel less when they fly their ferry range.
while you do not tackle those figures and acknowledge a reality that the F-111 carries more fuel at any configuration you are just barking but not biting.
therefore independently if you are a good engineer or not i think you are just boasting and not proving your facts with data taken from Sukhoi or the RAAF, since already at 51000kg the F-111 will be carring all its internal fuel and 11000kg or more of fuel tanks or weapons, around 30000kg rested from the empty weight of the F-111
also consider the F-111 has several variants and the Australian variant which is claimed to have a range of 5777km of range is the heaviest comparable only to the FB-111, the F-111A was lighter and has a shorter ferry range of 5093km
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By: Schorsch - 11th June 2008 at 10:36 Permalink - Edited 1st January 1970 at 01:00
Fortunately I haven't delayed any other activities.
But I guess further effort is wasted.
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By: Schorsch - 11th June 2008 at 10:41 Permalink - Edited 1st January 1970 at 01:00
I have all facts on the table and the results are very well documented in the published figures by Sukhoi for its own aircraft and for the F-111. They fit to the applied technology and make sense, when one understands it.
That is the factual situation.
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By: MiG-23MLD - 11th June 2008 at 11:44 Permalink - Edited 1st January 1970 at 01:00
Schorsch for me, you are just bluffing, to say you have all the data is like saying you have the manual of the Su-24 and F-111 at the same time, i do have three books about the F-111 and four about the Su-24 plus what i have read in the Sukhoi and RAAF webpages
You are just avoiding several questions.
A)what are the different ferry ranges for the FB-111, F-111A, F-111C and F-111F?
B)If the Su-24 flies with the same fuel an F-111 has at ferry range what would be the ferry range for the Su-24?
I have seen differences in weight between the F-111s variants ranging from 45000kg, 40000kg and 51000kg, also different ferry ranges quoted from more than 4700km to 5777km.
this ferry ranges also change with the variant becuase the FB-111 was a longer range bomber and the F-111C used by the Australian air force weighs the same.
All of this makes me to conclude the F-111A`s quoted range of 5090km and 45000kg weight with a 28000 liters fuel capacity is the average F-111 variant, if the Su-24 would have the same fuel carring capability of 28000 liters the Su-24 would have a range of 4400km or a Sukhoi quote range with one refueling of 5000km.
So i do not think the FB-111 has the same fuel capacity because the lighter EF-111 has a shorter range due to more electronic equipment.
In few words i do not think you are calculating your data realistically
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By: Sens - 11th June 2008 at 12:31 Permalink - Edited 1st January 1970 at 01:00
You are not afraid to cheat the people!
Data from Sukhoi: [conserative 0,78 kg density per litre]
14230 l intern + 8000 l extern = 22230 l for 3000 km or 7,41 l per km
Your data for the F-111A
28281 l total (intern+extern)for 5000 km or 5,66 l per km
When the lower value of 5,66 is the basic 100%, 7,41 is 130,9 % of that.
By the way, a number I did quote before.
All that high up, when the Tj is at its best.
But we discussed about the low-level range, where the Tf is at its best.
Even under best conditions high up the Su-24 is over 30% worse for every litre burned.
At low level the Su-24 is up to 100% worse.
The example does show for everyone to see. High up the Su-24 generates over 30% less range from every litre of fuel and when down on the deck it is even more worse.
For the other, it is not my intention to bash the producer of the Su-24, which were limited to that Tj-engine at hand. One of the best available Tj than, but still the wrong engine for a low level striker, which is in need of a Tf.
Just to bust that cloud of disinformation, by rising different numbers to proof nothing by that.
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By: MiG-23MLD - 11th June 2008 at 12:57 Permalink - Edited 1st January 1970 at 01:00
You are correct the Sukhoi webpage gives a higher internal fuel capacity for the Su-24Mk than the one AIRWAR ru uses, so my calculations did not consider that fact, i have been corrected.
Any way we have settled the issue, the Su-24MK carries more fuel that the one i quoted since airwar ru gives 9000kg and a total of 19000liters, however Sukhoi gives a higher internal fuel capability of 11100kg.
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By: franc - 11th June 2008 at 13:39 Permalink - Edited 1st January 1970 at 01:00
not three, two.
not so many as 8000 liters, 6000 liters approxi.
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By: franc - 11th June 2008 at 14:41 Permalink - Edited 1st January 1970 at 01:00
Let's keep them simply, unified all of units to liter.
2271 liters is the capacity of each external fuel tank F-111 could carry.
19112 liters is the internal fuel capacity F-111 carried
11883 liters is the internal fuel capacity carried by Su-24
3000 liters is the capacity that each external fuel tanks under wing glove of Su-24 contains
so we have those data fella:
Su-24 had internal fuel + external fuel = 11883 + 3000 * 2 = 17883 liters
F-111 got merely internal fuel 19112 liters, which still be greater than 17883 to 19112-17883=1229liters (about900-950kg)
please pay attetion to such little 1229 liters fuel won't cause so many gap of range between F-111 and Su-24, if the fuel consumption of engines these two jets fitted are similar. Noticed we had the 0.8 of Aardvark vs 0.76 of Fencer or 0.67 of Aardvark vs 0.76 of Fencer.
If all of other conditions are same, then 1229/19112, we got 0.064 which means, the F-111's range will only be longer than Su-24 6.4%.
If the SFC of engine F-111 used is 0.8, then [0.8-0.76]/0.8=0.05=5%, this will almost counteract the most of 6.4% longer range F-111 originally had. But if we used 0.67, then the advantage of range F-111 gained will be enlarged to 12%+6.4%=18.4%
The 18.4% is very much closer to the real gap of range 23%. The 23% come from [4700km -3600km]/4700km, if you insist the range of F-111 merely with internal fuel is 4700km. Where the rest 4.6% goes? I give it to the drag Su-24's external fuel tanks brought. If you guys insist the range of F-111 will be 5777km, I would also like to accept this data, then we will get 36.8% of advantage. 36.8-18.4=18.4 which will satisfied somebody who insist the drag coefficient external fuel tanks brought will be 20%. I think 18.4% is more reasonable for the EFT's drag coefficient.
Now we've done, each aspect can accept. The range of Su-24 even with two EFTs only reach 2/3 of F-111 can do with internal fuel only.
If we presumed both F-111 and Su-24 without external fuel tank, then 2775km range of Su-24 is reliable, so under this condition, then range of Su-24 will be only half range of F-111. 1/3 will be absolutely unacceptable.
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By: Schorsch - 11th June 2008 at 15:55 Permalink - Edited 1st January 1970 at 01:00
These SFCs are wrong.
We have actual data for TF30-P-412 (see my post page 2) and can see that for max military at 11km and M0.9 the SFC is about 0.9;
we use as representative for the AL-21 the data for the R-35 from the MiG-23ML aerodynamic manual. Page 76 and 78 give us about 1.13 for such conditions.
Now: (1.13-0.9)/0.9 = 25.5% more SFC.
Note: both infos are from Russian sources, downloadable from the net.
Using Breguet range equation:
[ATTACH]162843[/ATTACH]
W_initial is TOW.
W_final is TOW - Fuel
We assume a reserve fuel of 1000kg.
Fuel density is 0.8kg/l.
And for God's sake, we assume both aircraft to weight 22t operating empty and similar L/Ds.
[ATTACH]162844[/ATTACH]
Hence: The SFC alone yields a 33% range penalty.
Now drop in the extra drag through external tanks and you easily arrive at the given figures from the quoted websites.
2839nm equal 5230km.
Note: for 0km altitude the SFC difference is similar, about 25%.
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By: franc - 11th June 2008 at 17:00 Permalink - Edited 1st January 1970 at 01:00
Didn't change the consequence very much
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By: franc - 11th June 2008 at 17:02 Permalink - Edited 1st January 1970 at 01:00
Sens won't like the result you given, absolutely
:D:p:diablo:
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By: MiG-23MLD - 11th June 2008 at 17:38 Permalink - Edited 1st January 1970 at 01:00
Franc
I will be absolutedly honest with you, sukhoi qoutes a max internal fuel capacity of 11100kg see
Максимальный запас топлива во внутренних баках, кг 11100
Maximum internal fuel, kg 11,100
they do not mention how many liters it really carries internally a guessing as Sens said is close to 14000 liters, the Su-24 can carry three fuel tanks, however Sukhoi quotes a ferry range with only two fuel tanks
Ferry flight range with 2xPTB-3000 external fuel tanks, km:
- with PTB external fuel tanks dropped 2,775
http://www.sukhoi.org/eng/planes/military/su24mk/lth/
the vast majority of Russian sources and books i have say the Su-24 has an internal capability of around 9000 liters
see Запас топлива, л 11700
http://aviaros.narod.ru/su-24m.htm
Топливо
внутренние топливо, л 9800
ПТБ, л до 6610
see airwar ru quotes around 15000 liters
http://www.airwar.ru/enc/bomber/su24mk.html
however Airbase.ru goes along with Sukhoi a quotes a fuel weight of 16000kg
Массы и нагрузки
Су-24 Су-24М
Масса, кг пустого 22320 22300
топлива 16440 16440
максимальная взлётная 39700
http://airbase.ru/hangar/planes/russia/su/su-24/
However i have read also that the Russians were aware of the fact the F-111 has a much longer range but this was unimportant since the Russians had a different military doctrine.
in my opinion the Su-24 might have an engine with a real SFC of 0.76 as quoted by the russian sources however its lift and LD ratio limit the aircraft and it uses the engines in different ways the F-111 does, and as sadly it might sound for a fan of the Su-24 like i am it is true what Sens and Schorsch are saying, the general performance of the Su-24 makes it spend much more fuel.
In fact i just read that the Russians were aware of that short coming of the Su-24 and they wanted to build the Su-24MM with an AL-31 however the inlets were so narrow and they did not allow enough air for the engine
Но АЛ-31Ф отличался намного большим расходом воздуха через компрессор, и для них пришлось сделать третий воздухозаборник над фюзеляжем, выглядевший довольно необычно. За это Су-24ММ на фирме получил прозвище "мертворожденный монстр", которое оказалось пророческим - вскоре и эта программа была прекращена. На этот раз в пользу ударных модификаций одного из самых удачных самолетов ОКБ - Су-27.
But the AL-31F differed too much and had a larger flow of air through the compressor, and they had to make a third airlet over the fuselage, which looked quite unusual. For this, Su-24MM at the firm received the nickname "still-born monster", which proved prophetic - and soon the programme was discontinued in favor of a modification one of the most successful aircraft Su-27 (the SU-27IB).
http://www.airwar.ru/enc/bomber/su24m.html
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By: Schorsch - 11th June 2008 at 18:08 Permalink - Edited 1st January 1970 at 01:00
My results basically support each statement he did. I didn't plug in realistic weight data and used the fuel capacities you used. Including the effect of drop tanks would make the case even less desirable for the Suchoi 24.
Making a real missions assessment something that clearly exceeds the limit of what you do for an internet forum where many of the people not get the concept of SFC or L/D.
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By: franc - 11th June 2008 at 20:04 Permalink - Edited 1st January 1970 at 01:00
MiG, I'd prefer accept the result Schorsch given. The final data s/he given was more closer to my opnion and reach the reality much more. I can't see why it is impossible that the range of Su-24 by internal fuel only is 75% of Aardvark.
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By: Sens - 11th June 2008 at 20:18 Permalink - Edited 1st January 1970 at 01:00
Such a claim is called split identity or my understanding of English is very bad.
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By: Sens - 11th June 2008 at 20:47 Permalink - Edited 1st January 1970 at 01:00
Hi Schorsch,
three small details: The TF30-P-100 and P-414 are different and tuned for different missions as are the AL-21 and R-35 too. Even with two ETs dropped empty, Sukhoi do not claim more the 2775 km ferry range. The option of a third ET brings around 3000 km ferry range.
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By: Schorsch - 11th June 2008 at 22:04 Permalink - Edited 1st January 1970 at 01:00
That is accepted. But as I don't have SFC available for each engine in the world they set a useful yardstick to explain our fellows here the basics of aircraft engine design & performance. The data I gave can be considered representative for late 1960s engine design.
My little example was primarily aimed at showing the impact of a 25% higher SFC on overall range. If we plug in the correct weight data, assume the penalties for external tanks (and when they are dropped) and assess the rather tricky change of L/D for a swing wing aircraft (a ferry flight would most likely be done with wings swept fully forward, while a mission is mostly flown with wings in middle position). Then we also have to assume partial power SFC and flight profile.
However, no matter you turn it, the odds against the Suchoi 24 when it comes to range will not go away.