A review of studies conducted in 1986 indicates that a 300 passenger, 5500 nautical mile range aircraft should weigh less than 400,000 pounds. Some data from a British Aerospace Society of Automotive Engineers (SAE) paper will be shown that purport to be an advanced Concorde that meets the range payload specifications at a gross weight of 360,000 pounds. Previous studies by Peter Coen of Langley Research Center support these results. The weight of a supersonic transport is important from the point of view of how much effort should be expended in developing lower sonic boom technologies. It is obvious that a 360,000 pound aircraft can be modified to a more acceptable boom level than a 700,000 pound one

Driver, Cornelius

English

NASA Technical Reports Server

WHAT GROSS WEIGHT AND RANGE FOR AN ADVANCED HSCT? 
c 
Cornelius Driver I .  
Eagle Engineering, Inc. 
Hampton, VA 
Abstract 
A review of studies conducted in 1986 indicates that a 300 passenger, 5500 nautical mile 
range aircraft should weigh less than 400,OOO pounds. Some data from a British Aerospace 
SAE paper will be shown that purports to be an advanced Concorde that meets the range 
payload specifications at a gross weight of 360,000 pounds. Previous studies by Peter Coen 
of Langley Research Center support these results. 
The weight of a supersonic transport is important from the point of view of how much 
effort should .be expended in developing lower sonic boom technologies. It is obvious that a 
360,000 pound aircraft can be modified to a more acceptable boom level than a 700,000 pound 
one. 
INTRODUCTlON 
The H S n  System Studies have codinned a 30 to 40 percent increase in market 
penetration of an HSCT that can fly overland compared to one that cannot. This market 
size factor, like the selection of the proper range-payload and Mach number, deserves all the 
attention that can be generated for the vehicle to be a success. A review of the HSCT work 
reported over the past 5 years would suggest that inadequate resources may have contributed 
to the lack of use of the most advanced technologies. While this perspective may seem harsh, 
it is difficult to rationalize the configuration gross weights now being shown. 
From a sonic boom perspective, a 700 or 800 thousand pound vehicle will be most 
difficult to modify in such a way as to make its overpressure level low enough to raise the - 
possibility of being acceptable. In fact, the magnitude of this perceived problem may lead to 
d u c e d  sonic boom research and concentration on over water configurations only. This course 
could turn out to be disastrous if it turns out to be incorrect. 
The question is are there combinations of payload, range, and technology levels that 
could provide the capability to carry 250 passengers 5500 nautical miles for gross weights of 
about 360,000 pounds (about half the present study configuration weights). There should be no 
question that altering a 360,000 pound configuration to attain a specified low boom level is an 
https://ntrs.nasa.gov/search.jsp?R=19920076744 2020-03-24T07:22:38+00:00Z
46 
easier task than uying to achieve that level with a starting point of 700 or 800 thousand pounds. 
Fortunately, there are two advanced Concorde studies (Refs. 1 and 2) that support that a 360,000 
pound vehicle may be able to carry 250 passengers 5500 nautical miles. 
4 
' ( .  
DISCUSSION 
The results of several past studies and an array of technology improvements support the 
contention that present day systems studies should yield lighter weight supersonic cruise 
transporn. 
Let us start then with a review of the dollars spent in support of supersonic technologies in 
the United States (see fig. 1). First, a considerable amount of effort has already been paid for and 
should be used to the fullest extent. The SCR Program shown spent approximately 130 million 
dollars over 8 years at an average cost of about $3O,OOO/man-year; today, three times that amount 
would have to be spent to generate the man hours expended in that program. It is apparent to me 
that a lot more resources are required to generate a reasonable level of effort in the supersonic 
technology area. A major portion of the SCR funds were spent on noise reduction, advanced 
propulsion, titanium sandwich construction, and sonic boom. Substantial advances were made in 
each of these areas and should be showing up in the study configurations in terms of reduced 
takeoff gross weight. 
Another primary source of weight reductions is in the advanced subsonic aircraft shown 
on figure 2. All of these aircraft have technologies not in use when the previous SST Program 
ended or even when the SCR Program ended in 1980. Technologies, such as the two-man 
cockpit, advanced engines running at temperatures of 26OO?F, carbon brakes, light weight seats 
and galley, the application of composites in tails and floor beams - each of these technologies have 
twice the gross weight reduction payoff on an SST compared to a subsonic aircraft. Have we 
incorporated a l l  the weight reduction items presently in use in the subsonic aircraft in the HSCT 
study aircraft? 
I submit that the competitor to an advanced HSCT are these two-engine, long-range 
subsonic airplanes that leave from any local ahport and fly directly where I wish to go. If I have 
to fly subsonic to an airport to catch an HSCT flight, then I have forfeited a larger portion of my 
mp time savings before the SST flight even begins. 
Since two studies have been perfomed applying advanced technology to the Concorde, let 
us begin with those studies (refs. 1 and 2). The present Concorde in commercial service was 
designed and prototyped in the 1960's and entered commercial series in 1976. Since it has 
completed over 50,000 flight cycles in commercial service at M = 2.05 it provides a credible base 
or reference point (see fig. 3). 
If the Olympus engine on the Concorde was redesigned today, it would weigh nearly half 
as much as the original engine and have 1/2 the number of compressor stages and 1/2 the part 
count (see fig. 4). It would be about 10oO ?F hotter and have at least a 15 percent lower SFC. 
. 
. 
. 
. 
Most of these advances, including digital fuel controls are flying on advanced commercial and 
military engines today. Coen’s analysis (xf. 1) showed that similar technology improvements 
would reduce the gross weight 150,000 pounds if the range were held constant or the range would 
hma~e18W fiiiiiiiu~id d e s  if the ~ O S S  weight w e l t  heid constant Tnis resuit was obtained 
using the original Concorde weights and aerodynamics. 
Coen’s paper also examined the payoff of advanced aerodynamic features such as 
planform, thickness, camber and twist, and paying attention to area rule principles in the layout of 
the configuration. His results were almost as dramatic as the payoffs in propulsion; at a constant 
range the gross weight was reduced to 280,000 pounds; at constant gross weight the range was 
increased 1200 nautical miles (see fig. 5). 
The recent British aerospace study reported in reference 2 shows a second generation 
Concorde with many of the features described by Coen in his study done in 1986. The advanced 
Concorde is a tailless configuration and utilizes fuel transfer for cg control as in the original 
design. ( It uses a small canard to trim the trailing edge flap down configurations for landing and/ 
or takeoff.) Note that it is designed to carry 280 passengers (see fig. 6). 
Note that the bars are labeled “Today’s” technology, assumed for baseline aircraft, and 
required for viable aircraft (see fig. 7). Note, also, that they do not mention the engine weight 
reduction, only the SFC reduction. Finally, note that the Coen study showed larger L/D gains and 
today’s structural weight reduction levels. This figure indicates that most of the necessary 
technical progress required to provide a viable configuration is already in hand. Only a small 
further technology increment is requixed and that may be partially made up by the “extra” 
aerodynamics available. 
The message from figure 8 is that most of the technology required for an advanced SST is 
already in hand. The figure indicates what is needed is about 1000 miles range at a constant gross 
weight. From Coen’s study, several answers are available. For instance, the L/D improvement of 
20 percent shown in the previous chart is only 8.74, 30 percent is 9.49, and 40 percent is 10.22. 
Certainly 9.5 at Mach 2.05 is feasible today. While the Olympus was, and is, a great supersonic 
engine, it is st i l l  a 25 year old design derived from a predecessor designed in the 1950’s. Digital 
controls and variable bypass offer the promise of at least the 10.22 percent sfc improvement 
desired. 
When Coen (ref. 1) applied all the advances at once, he showed a gross weight of 304,000 
pounds to cany 200 passengers 5500 miles. The British Aerospace study indicated 363,000 for 
280 passengers 5500 miles (see fig. 9). An advanced Concorde then offers a reasonable way to 
apply the new technology to an advanced configuration. Certainly we should be working on a 
sonic boom problem based on a 360,000 pound gross weight not 700,000 to 800,000. Since Ap 
overpressure is approximately proportional to the dw this reduction in gross weight would reduce 
the boom by more than 40 percent. The boom reduction available by flying above 60,OOO feet 
instead of about 50,000 feet results in another 40 percent reduction in boom level. Design 
restrictions, such as NO, reduction criteria that quires reduced altitude and Mach number 
. - 
. 
* 
47 
1. 
2. 
SUMMARY c .  
It is probably appropriate that an advanced Concorde be utilized as a reierence 
configuration between the Government and the contractors. 
AmWng a meaningful sonic boom overpressure reduction is tough enough without 
starting with takeoff gross weights that may be twice as heavy as required to perfom 
the mission. 
W b l e  data exists that indicates that 250 passengers can be carried 5500 nautical 
miles with takeoff gross weights of about 360,000 pounds. 
Artificial restraints of altitude or Mach number only make the design decision tougher 
and may inadvertently lead to the wrong conclusions. 
REFERENCES 
Coen, P. G.: The Effect of Advanced Technology on t.e Second-Generation SST. 
NASA Langley Research Center, AIAA/AHS/ASEE Air& Systems, Design 
and Technology Meeting, Dayton, Ohio, 1986. 
Liddell, Peter W.: Prospects for a Second Generation Supersonic Transpod. Presented at 
the SAE Amtech 1991 Aerospace Technology Conference and Exposition, September 
23-26, 1991, Long Beach, California. 
. 
i 
A 
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1960 1970 1980 1990 2000 
YEAR 
Figure 1. Funding history. 
Figure 2. Subsonic aircraft competitors. 
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Concorde 1971 1977 Arrow 
SST SST Wing 
Figure 5. Effect of aerodynamic improvements on lifthag ratio. 
n n 
1 1  -1 
Area ruled fuselage 
D e  
Wing camber optimised 
for supersonic cruise 
I A.S.T. I Concorde 
7,483 4,600 
117 8.4 
I .74 1.53 
311 201 
50s 400 
159 
280 100 
- 
. 
Figure 6. - Advanced supersonic transport study - datum aircraft. . . -  . 
. 
Base is 
Concorde 
Aerodynamics Materialsl 
Cruise U D  structural 
optimisation 
Structure - weight 
Powerplant 
cruise SFC 
40.5% 
c] “Todays” technology 
0 Assumed for baseline aircraft 
Required for viable aircraft 
Figure 7. Advanced supersonic transport study technology standards relative to 
Concorde. 
Aircraft Size 
2.0 I I A I 
“Todays” 
Technology 
1.8 ’ 1 Concorde 
“Airframe” 
Technology 1.6 
1.4 Y 
Assumed AST 
0.4 5,000 5300 6,000 
3,000 3,500 4,000 4500 
Range NMLS Meets Far 36 Stage 3 
Figure 8. Advanced supersonic transport study-feasiblity of achieving AST 
technology standards. ” 
* 
53 
Passengers 
251 
200 
150 
100 
50 
0 
360,000 Ibs Advanced SST 
1 8 1 8 f I 1 \* & 
0 1 2 3 4 5 6  7 8 9 
Range (1000 n.mi.) 
c 
1 
Figure 9. Range-payload curve for advanced t wo-engine SST. 
54 
. . 
. 


What gross weight and range for an advanced HSCT?

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