The Code one article is flawed, and contradicts the pilots account and the research data as given in the Swedish research thesis and LM patent.

http://liu.diva-portal.org/smash/record.jsf?pid=diva2:221

See my previous two posts for details.

The record can only be put straight with the right information, so I would request any forum members who are engineers to perhaps help set the record straight.

As I understand it, from reading about it a while ago and from memory of reading in hard copy the DSI F-16 testbed pilot’s interview, here is how I understand it (and again I am speaking from memory so open to correction):

1. Generally three types of inlets: i)Fixed ii) Variable iii) DSI

2. Variable inlets are maintenance intensive. Fixed and DSI, are not. DSI does not have a maintenance or cost advantage here against fixed inlets.

3. Fixed inlets suffer performance penalties, variable inlets provide the best performance across all regimes and DSI provides performance superior to the fixed inlet but does not cover the full range of performance of variable inlets.

4. The F-16 has fixed inlets. It does not lower operational costs by adopting DSI intakes. In contrast, the F-15 has variable inlets.

5. DSI intakes here would improve the performance of the F-16, not by much but still so. The reason it was not adopted was because i) USAF was not willing to fund it (for whatever reasons) ii) Would require extensive testing which would be costly iii) The cost-benefit of the above two made a LM private venture into this, vis-a-vis a small performance benefit, uneconomic.

6. Because the JSF was being designed from the ground up, it had no problems incorporating the DSI intakes.

7. DSI intakes were one of a number of modifications made to improve the performance of the JF-17, after the PAF deemed it needed to be improved to be competitive against IAF FLANKERs. Originally, the JF-17 had fixed inlets just like the F-16.

8. An interesting point here is that, as I remember the test pilot from the interview said, its as if the PW engine was changed for the more powerful GE engine… smooth throttle, etc. But bear with me here, the F-16 always had a healthy amount of thrust, and here the benefit is marginal.

Comparatively, the JF-17 has always been flet to be slightly deficient in that regard, and here the payoff of DSI just may be greater. In this regard, both the JF-17 and JSF are in the same boat.

Would gladly like to hear from aerodynamics professionals or other informed posters out there to explain this better, or to correct what I’ve said.

Edit: just found this from the patent filed by LM and info from American Institute of Aeronautics and Astronautics thanks to Teg from F-16.net:

Here is LM’s patent, lots of cool info there (only 18 pages long!)
http://www.freepatentsonline.com/5749542.pdf

LM wrote:
In particular, the present invention does not require a boundary layer diverter, a side or splitter plate, a boundary layer bleed system or an overboard bypass system. Furthermore, the present invention has no moving parts. This reduction in complexity reduces the tactical fighter aircraft’s empty weight, production cost, and maintenance support requirements. These savings are estimated to be 250 pounds per aircraft, $225,000 per aircraft, and 0.03 maintenance man hours per flight hour, respectively.

AAIA members have also studied the DSI’s performance;
http://pdf.aiaa.org/preview/2010/CDRead … 10_481.pdf

American Institute of Aeronautics and Astronautics wrote:
Flow Field and Performance Analysis of an Integrated Diverterless Supersonic Inlet. In this paper the computed flow and performance characteristics at low angle-of-attack (AOA) of an integrated Diverterless Supersonic Inlet (DSI) are presented near its design mass flow rate. The subsonic characteristics are evaluated at M?=0.8 while the supersonic characteristics are evaluated at M?=1.7, which is near the design Mach number for the intake. In addition to the external flow features, the internal intake duct flow behavior is also evaluated. The results of this study indicate effective boundary layer diversion due to the “bump” compression surface in both subsonic and supersonic regimes. At M?=1.7, the shockwave structure (oblique / normal shockwave) on the “bump” compression surface and intake inlet is satisfactory at intake design mass flow ratio. The intake duct flow behavior at subsonic and supersonic conditions is generally consistent with “Y” shaped intake duct of the present configuration. The secondary flow structure inside the duct has been effectively captured by present computations. The computed intake total pressure recovery at M?=1.7 exhibits higher-then-conventional behavior at low mass flow ratios, which is attributed to inlet design feature. Overall computed subsonic and supersonic total pressure recovery characteristics are satisfactory under the evaluated conditions and are also in agreement with wind tunnel test data.

http://www.f-16.net/index.php?name=PNphpBB2&file=viewtopic&p=181064

The dsi f16 was a test bed not an operational aircraft. The interview of the dsi f16 test pilot indicates otherwise as to the improvement in the performance, this interview is published.

Just wondering what other operational fighter had dsi intakes.