The circular pressure hull that constitutes the fuselage ahead of and behind the wing structural carry-through box is cut-out to allow the box through to connect the wings that must carry bending moments and torques generated by the wings and reacted through the fuselage. The pressure loads on the fuselage have to be supported by flat panel pressure bulkheads ahead of the wing box, the floor over the wing box and down just aft of the main landing gear box. The forward and aft bulkheads are tied together and the fuselage bending loads are carried through a "keel beam" that can be seen running longitudinally, even with the lower surface of the fuselage, between the left and right main gear wells. Structural discontinuities such as these are both difficult to accurately model and are material intensive and heavy. Adding a lot of structural margin is costly, so failures initiating at these features tend to be more common. Thus the instrumentation and test.

(Written on 29-11-2019)(Permalink)

You must mean the McDonald types. Leave Douglas out of this!

(Written on 01-11-2019)(Permalink)

My understanding is that the fan shroud is designed to contain any fan blade separations. This was the argument against propellers and unducted fans. The accident at Soiux City was explained away that the blisk failed there and in that case the parts were too heavy and contained too much energy to stop with flight structure. Why is it that there has been no discussion as to why the blades were not contained by the fan shroud?

(Written on 20-04-2018)(Permalink)

Yeh, but they make more in a year or two than you or I will in a lifetime.

(Written on 16-02-2018)(Permalink)

Seems that the FAA should work with the AMA in a similar manner they currently work with the USPA (U.S. Parachute Association).

(Written on 26-05-2017)(Permalink)

Sorry Sparkie, the "pitch" of a typical GA prop is about 5 feet. This means that for a two blade prop, there is a blade passage every 2 feet or so. More than enough room for a bird or drone to pass through whole or in part.

(Written on 26-05-2017)(Permalink)

What a waste of time and money. Seems to be mainly there to prevent banner towing that might bother the spectators. If some nefarious entity wished to do nefarious things, the fighters would have less than 2 minute from the time the lawfully operated buiz-jet makes a 90 deg turn (5 miles out) to passing over (or into) the stadium. What is it they are going to do anyway? Shoot down a loaded jet over one of the most populated areas on the West coast? Just what the neighborhood needs; 30 mm depleted uranium slugs coming through the roof, followed by a block-long splash of burning jet fuel. his policy is just another impediment to free travel about the United States. Invisible land mines in the air to snag the unwary.

(Written on 05-02-2016)(Permalink)

This regulation seems to be a knee-jerk reaction to the fear that the sky will be darkened by this class of flying machine, although there is yet to be a documented collision involving them. Legally classifying them as "aircraft" has many interesting consequences: re-registration and airworthiness certificates every three years, assigned N-numbers to be displayed in 18" tall figures (banner towing?), deregistration on being deemed non-flight worthy, and that the elephant in the room: pilot certificates (drone endorsement?). If other people's experience is similar to mine, the FAA will be swamped under the continuous traffic of registrations, de-registrations, modification paperwork accident reports etc. etc. Are form 337s going to be required for major repairs a modifications? Log books for both the pilots and aircraft? Annual inspections? Considering the value of many the these pieces of flying art, the NTSB could get involved too. The FAA has stepped into a quagmire of its o

(Written on 18-12-2015)(Permalink)

SpaceX tried a number of times to recover boosters using aero drag and parachutes. The boosters broke up or were damaged beyond the ability to deploy the parachutes during the initial uncontrolled atmospheric entry.

(Written on 28-11-2015)(Permalink)

This was, in a way, much more difficult and complicated than the lunar landing due to the atmosphere that interacted with the exhaust plume in very powerful and non-intuitive ways.

(Written on 28-11-2015)(Permalink)