Supersonic Airliner design using Joint wing (Diamond wing) - Part 2

 

Previous Work Status

- Initial Kick-Off & Design Progress

The new topic for My page : Optimization of Supersonic aerodynamic aircraft
Supersonic Airliner design using Joint wing (Diamond wing) - Part 1

- Other Supersonic Jet or Innovative Design Reference

Boeing's New Truss-Braced Wing

Boeing's E-X project

Various SST project images
Boomsupersonic's XB-1

Aerionsupersonic AS2's Major update

Boomsupersonic Design

- Performance Evaluation via Missile / Flight-SIM

Missile-SIM : Performance Evaluation for Iskander / Kh-47M2 Kinzhal & ATACMS+Booster

Flight-SIM : Trajectory & Performance Analysis for Jet Aircraft

Flight-SIM : DB Structure of the SIM

Flight-SIM : W.I.P of the SIM

Flight-SIM : Generic DB of single-aisle Airliner : Part 1 

Flight-SIM : Generic DB of single-aisle Airliner : Part 2

Flight-SIM : W.I.P of the SIM II

Flight-SIM : Initial Version of the Flight-SIM w/ Demo
Flight-SIM : Initial Version of the Flight-SIM w/ Demo II

2. Construction of Aerodynamic/Propulsion/Weight DB

1) Weight DB

 Weight of the aircraft is estimated from the reference as shown in the Figure below. Reference roughly configured the weight of the Truss-Wing as 65% of the conventional wing. From this result, the ZFW (Zero-Fuel-Weight) is saved about 3 tons. 

2) Propulsion DB

 Basically I made no difference on the thrust value of the CFM-56 class engine while I assumed pressure recovery data based on the 3 shock inlet. 

3) Aerodynamic DB

 Geometry of the two aircraft, SupLiner Mk.1 and A320 are shown; similar size of cabin and engine are represented. Only modification of the engine is added shock-cone to gain enough pressure recovery value in the supersonic condition. 

 Specific estimation result for the generic A320 class airliner is shown in my previous article (Flight-SIM : Generic DB of single-aisle Airliner : Part 2). 

 Truss-Supersonic wing having less camber and incidence angle has much smaller CL value at the given AoA while it gives much smaller drag than the conventional wing due to its swept angle. 

 Truss-Supersonic wing shows similar L/D in M0.4~0.7 condition where the generic A320 mainly flight. However, in Mach 0.9, where the drag of the conventional one is already risen, Truss-Supersonic wing surpass max L/D value of the conventional one. 

 In supersonic region, M1.1~1.8, estimation of the aerodynamic value is only calculated for the Sup-Liner; Cl_aoa value is peaked at M1.1 and reduced. Minimum drag is in 'drag-rise' at M1.1, so, L/D become lower than the conventional's subsonic case. 

 Flight-SIM will evaluate Range and Fuel economy performance in the next article. 

 CFD result is supplementary provided (Mesh, iteration, case set up are very rough compare to the full-academic or industrial purpose set up due to '4-core laptop for FLUENT'; please understand about it)

M1.1 AoA 0deg - Mach Contour

M1.8 AoA 6deg - Mach Contour

M1.8 AoA 6deg - Pressure Contour

Supersonic Airliner design using Joint wing (Diamond wing) - Part 1

Previous Work Status

- Initial Kick-Off & Design Progress

The new topic for My page : Optimization of Supersonic aerodynamic aircraft

- Other Supersonic Jet or Innovative Design Reference

Boeing's New Truss-Braced Wing

Boeing's E-X project

Various SST project images
Boomsupersonic's XB-1

Aerionsupersonic AS2's Major update

Boomsupersonic Design

- Performance Evaluation via Missile / Flight-SIM

Missile-SIM : Performance Evaluation for Iskander / Kh-47M2 Kinzhal & ATACMS+Booster

Flight-SIM : Trajectory & Performance Analysis for Jet Aircraft

Flight-SIM : DB Structure of the SIM

Flight-SIM : W.I.P of the SIM

Flight-SIM : Generic DB of single-aisle Airliner : Part 1 

Flight-SIM : Generic DB of single-aisle Airliner : Part 2

Flight-SIM : W.I.P of the SIM II

Flight-SIM : Initial Version of the Flight-SIM w/ Demo
Flight-SIM : Initial Version of the Flight-SIM w/ Demo II

1. Initial Concept of Supersonic Aircraft

 As I described earlier, I attempt to design a new supersonic aircraft; until now, size, initial concept of the aircraft is not fixed. Also, tool for the performance evaluation is under the development. 

 My own Flight-SIM code will be act as range / flight trajectory evaluation tool; CAD/CFD work will provide aerodynamic DB for my new design. Weight and propulsion DB will be estimated from proper reference and estimating equation. 

Boeing's New Truss-Braced Wing

Boeing released their new aircraft having Truss-Braced wing type

http://www.boeing.com/features/2019/01/spreading-our-wings-01-19.page

 Actually, Boeing already have own experience related to the joint wing as described in this blog

http://jaesan-aero.blogspot.com/search/label/Joint-Wing

 This E-X concept is more radical than the Truss-Braced type, and type category of joint-wing is shown below [1]

Fig. 2. Type of Joint-Wing [1]

 Although there were several prototype attempt to materialize joint wing (https://www.secretprojects.co.uk/forum/index.php/topic,4963.75.html), Boeing's one is interesting that there is no project like this in recent years. Boeing emphasized this project focuses fuel saving and noise reduction. From the reference [1], it might cause non-linear problem for the aerodynamic and stability perspective. 

 Complexity of the wing shape is caused by tandem configuration of the wing and joint-part generating complex flow configuration while aero-elastic problem also should be considered.. 

Fig. 3. Pressure distribution of the joint wing and its optimized shape [1]

 Optimized shape of Truss-Braced wing could achieve higher L/D and more payload than conventional shape as described in Fig. 4 [1]. L/D is increased from 26 to 32 however, increase of structure weight is significant. Finally, Boeing current concept is very similar to that of Fig. 5, class of mid-range airliner cruising at transonic speed. Anyway, it is interesting to watch the development of the old-new concept. 

Fig. 4. Optimized shape of Braced-wing [1]

Fig. 5. Optimized shape of Braced-wing similar to Boeing's current concept [1]

[1] Cavallaro, R and Demasi, L., 2016, Challenges, Ideas, and Innovations of Joined-Wing Configurations : A Concept from the Past , an Opportunity for the Future, Progress in Aerospace Sciences

Boeing's E-X project

Pic. Source : https://www.secretprojects.co.uk/forum/index.php

 As a candidate of surveillance aircraft of USN, Boeing had proposed joint wing design. Most of the sensors are mounted on the wing, and Boeing insists it could cover and provide better sensor capability than existing systems. 

 It should be noted that complex flow pattern at the wing tip of the joint wing is studied via wind-tunnel testing. Fuselage design is similar to S-3, and engine pod is attached at the side of the body where downstream of the wing is worried. 

 Joint wing is expected to have advantage in lift/drag ratio and structural fatigue aspect, and this is why Boeing chosen this design for long-time endurance aircraft. But, sill, complex control of CG, and engine position could be trouble some phenomena when the design of the aircraft is matured. 

 Additionally, rear wing part tends to be lower or higher position than front wing to avoid downstream of the front wing which degrades performance and handling qualities or stability. In that design, if rear wing is swallowed by downstream of the front wing, aircraft could enter the severe departure status than the conventional ones.