По прочности.
Я много писал на эту тему, но с удовольствием продолжу.
Я лично бывал на заводах сборки Cessna и Quest Aircraft и как авиационный инженер, могу сказать, Кодьяк невероятно прочнее, что и видно в момент сборки. Это не упоминая, других конструкторских решений. При проектировании, что не скрываеться, принимали Cessna Grand Caravan как модель, но изменяя конструкцию для более больших нагрузок и настоящего испытания поверхностью, размерами посадочных площадок, скороподьемности, итд.
Основным фактором, влияющим на невероятную прочность, что вы могли заметить в аварии под Псквом, это то что Кодьяк разрабатывался гораздо более позже всех своих "одноклассников" (Cessna Caravan, PC-6, PAC-750) и стандарты FAA для разработки, производства и испытаний, изменились десятикратно.
Ниже я предлагаю документ, сравнивающий Кодьяк с С-208, как раз в этом аспекте.
Дайте знать, если я могу Вам помочь с переводом.
Обратите внимание, что по многим нынешним требованиям к дизайну, во времена разработки С-208, они вообще отсутствовали.
Более 1000 индивидуальных изменеий внесено с Стандарты Сертификации со времен Цессны (редакция 28) ко временам Кодьяка (редакция 59)
The Value of a Modern Design Aircraft
What it means when comparing the KODIAK to older aircraft:
Often questions arise regarding the differences between the Quest KODIAK and the Cessna Caravan. Because the two airplanes appear similar, both high wing turboprop with a fixed landing gear, and are sometimes mistaken for each other, this paper will point out a few key differences based on the Federal Aviation Administration Certification requirements between the two airplanes.
Though the design purpose or mission of the KODIAK is significantly different, which results in a superior aircraft in many ways over that of the C208, the mandates of modern certification requirements are evidence that the KODIAK truly is a vastly superior aircraft.
Both the KODIAK and the Cessna 208 are designed following requirements of 14CFR Part 23 – the rules governing the design and certification requirements of general aviation aircraft. Over time, the FAA has added to the certification requirements through Amendments. The Cessna Caravan was certified under amendments 23 to 28. The KODIAK was certified under Amendments 55 to 59.
In general, the FAA issues amendments to clarify and increase safety of aircraft coming to the market. An FAA official once remarked, “Most rules and amendments are written in blood, they come about by the need, borne of experience, to address an issue to protect the safety of people.” There are almost 1000 individual changes to the regulations between Amendment 28 and Amendment 59, most pertaining to increases in safety.
Here are some significant examples:
Seats Certification under the Certification Amendment basis, mandated that the KODIAK require dynamic testing (sled test with crash test dummy), and pass 26G forward and 19G vertical for crew seats, and 21G forward and 15G vertical for passengers . FAR 23.562(B)(2)(3), FAR 23.562(B)(1) Prior to 1988, there was no requirement to prove a design with sled testing and at that time, seats were only designed for 9G. Example, see footnote 1
In addition to the increase of demonstrated G loads for crew and passengers, a number of other safety‐
related criteria were also added to the occupant restraint systems having to do with head injuries. Example, see footnote 2
“Items of mass” in the cabin (i.e. cargo, fire extinguishers) are required to be evaluated and pass higher G loading than before. The KODIAK certification basis requires an 18G forward and a 4.5G sideward load
as opposed to the earlier Amendment, which only required a 9G forward and 1.5 sideward loads. See footnote 1
Flammability requirements were added for cargo compartment materials (external cargo compartment) to be the equivalent to interior flammability and added the requirement to protect against ignition sources in cargo compartments. Example, see Footnote 3
Additional requirements were added to certify designs to handle the direct and indirect effects of lightning. Example, see footnote 4
Other significant items included: requirements for additional fire extinguishers, increase in static seat strength, demonstration of engine failure at 50’ during takeoff, plus numerous administrative or incremental safety changes. Example, see footnote 5
Conclusion:
The above examples are only a small sample of how the vast changes between the early 1980s and 2005 affects design philosophy. The net result is an airplane, the KODIAK, which meets the latest, most stringent FAA Certification requirements for crashworthiness, survivability and safety. This translates to a highly rugged, useable, flyable aircraft. Add to that requirement, the design philosophy of Quest Aircraft Company to design and build an aircraft to operate in the most remote, in‐hospitable areas of the world, the KODIAK clearly is a magnificent flying machine.
General Questions and Answers:
Does this mean the 208 is not safe?
No, of course not. If just doesn’t meet the latest and most stringent requirements of the FAA.
Is the C208 as strong as the KODIAK?
The Caravan was designed to an older, lower standard and extensive, dynamic testing was not required to prove their design. Nor was the 208 designed in anticipation of continuous use in remote in‐ hospitable and off‐airport operations.
Footnote 1
FAR 23 Section 561b
C208 basis:
(b) The structure must be designed to give each occupant every reasonable chance of escaping serious injury in a minor crash landing when‐‐
(1) Proper use is made of the belts or harnesses provided for in the design; and
(2) The occupant experiences the ultimate inertia forces shown in the following table:
Ultimate Inertia Forces Normal and utility categories Acrobatic category Upward‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ 3.0g 4.5g
Forward‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ 9.0g 9.0g
Sideward‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ 1.5g 1.5g
(d) If a turnover is reasonably probable, the structure must be designed to protect the occupants in a complete turnover, assuming, in the absence of a more rational analysis‐‐
(1) An upward ultimate inertia force of 3g; and
(2) A coefficient of friction of 0.5 at the ground.
KODIAK basis:
(b) The structure must be designed to protect each occupant during emergency landing conditions when:
(1) Proper use is made of seats, safety belts, and shoulder harnesses provided for in the design;
(2) The occupant experiences the static inertia loads corresponding to the following ultimate load factors‐‐
(i) Upward, 3.0g for normal, utility, and commuter category airplanes, or 4.5g for acrobatic category airplanes; (ii) Forward, 9.0g;
(iii) Sideward, 1.5g; and
(3) The items of mass within the cabin, that could injure an occupant, experience the static inertia loads corresponding to the following ultimate load factors‐‐
(i) Upward, 3.0g;
(ii) Forward, 18.0g; and
(iii) Sideward, 4.5g.
(iv) Downward, 6.0g when certification to the emergency exit provisions of Sec. 23.807(d)(4) is requested;
(a) Each seat/restraint system for use in a normal, utility, or acrobatic category airplane must be designed to protect each occupant during an emergency landing when‐‐
(1) Proper use is made of seats, safety belts, and shoulder harnesses provided for the design; and
(2) The occupant is exposed to the loads resulting from the conditions prescribed in this section.
(d) For all single‐engine airplanes with a of more than 61 knots at maximum weight, and those multiengine airplanes of 6,000 pounds or less maximum weight with a of more than 61 knots at maximum weight that do not comply with Sec. 23.67(a)(1);] (1) The ultimate load factors of Sec. 23.561(b) must be increased by multiplying the load factors by the square of the ratio of the increased stall speed to 61 knots. The increased ultimate load factors need not exceed the values reached at a of 79 knots. The upward ultimate load factor for acrobatic category airplanes need not exceed 5.0 g.
(2) The seat/restraint system test required by paragraph (b)(1) of this section must be conducted in accordance with the following criteria:
(i) The change in velocity may not be less than 31 feet per second.
(ii) (A) The peak deceleration () of 19g and 15g must be increased and multiplied by the square of the ratio of the increased stall speed to 61 knots:
(B) The peak deceleration need not exceed the value reached at a of 79 knots.
(iii) The peak deceleration must occur in not more than time (tr), which must be computed as follows:
where‐‐
= The peak deceleration calculated in accordance with paragraph (d)(2)(ii) of this section; and
tr = The rise time (in seconds) to the peak deceleration.
(b) Except for those seat/restraint systems that are required to meet paragraph (d) of this section, each seat/restraint system for crew or passenger occupancy in a normal, utility, or acrobatic category airplane, must successfully complete dynamic tests or be demonstrated by rational analysis supported by dynamic tests, in accordance with each of the following conditions. These
tests must be conducted with an occupant simulated by an anthropomorphic test dummy (ATD) defined by 49 CFR Part 572, subpart B, or an FAA‐approved equivalent, with a nominal weight of 170 pounds and seated in the normal upright position.
(1) For the first test, the change in velocity may not be less than 31 feet per second. The seat/restraint system must be oriented in its nominal position with respect to the airplane and with the horizontal plane of the airplane pitched up 60°, with no yaw, relative to the impact vector. For seat/restraint systems to be installed in the first row of the airplane, peak deceleration must occur in not more than 0.05 seconds after impact and must reach a minimum of 19g. For all other seat/restraint systems, peak deceleration must occur in not more than 0.06 seconds after impact and must reach a minimum of 15g.
(2) For the second test, the change in velocity may not be less than 42 feet per second. The seat/restraint system must be oriented in its nominal position with respect to the airplane and with the vertical plane of the airplane yawed 10°, with no pitch, relative to the impact vector in a direction that results in the greatest load on the shoulder harness. For seat/restraint systems to be installed in the first row of the airplane, peak deceleration must occur in not more than 0.05 seconds after impact and must reach a minimum of 26g. For all other seat/restraint systems, peak deceleration must occur in not more than 0.06 seconds after impact and must reach a minimum of 21g.
(3) To account for floor warpage, the floor rails or attachment devices used to attach the seat/restraint system to the airframe structure must be preloaded to misalign with respect to each other by at least 10° vertically (i.e., pitch out of parallel) and one of the rails or attachment devices must be preloaded to misalign by 10° in roll prior to conducting the test defined by paragraph (b)(2) of this section.
(c) Compliance with the following requirements must be shown during the dynamic tests conducted in accordance with paragraph (b) of this section:
(1) The seat/restraint system must restrain the ATD although seat/restraint system components may experience deformation, elongation, displacement, or crushing intended as part of the design.
(2) The attachment between the seat/restraint system and the test fixture must remain intact, although the seat structure may have deformed.
(3) Each shoulder harness strap must remain on the ATD's shoulder during the impact.
(4) The safety belt must remain on the ATD's pelvis during the impact.
(5) The results of the dynamic tests must show that the occupant is protected from serious head injury.
(i) When contact with adjacent seats, structure, or other items in the cabin can occur, protection must be provided so that the head impact does not exceed a head injury criteria (HIC) of 1,000.
(ii) The value of HIC is defined as‐‐
Where:
t1 is the initial integration time, expressed in seconds, t2 is the final integration time, expressed in seconds, (t2‐t1) is the time duration of the major head impact, expressed in seconds, and a(t) is the resultant deceleration at the center of gravity of the head form expressed as a multiple of g (units of gravity).
(iii) Compliance with the HIC limit must be demonstrated by measuring the head impact during dynamic testing as prescribed in paragraphs (b)(1) and (b)(2) of this section or by a separate showing of compliance with the head injury criteria using test or analysis procedures.
(6) Loads in individual shoulder harness straps may not exceed 1,750 pounds. If dual straps are used for retaining the upper torso, the total strap loads may not exceed 2,000 pounds.
(7) The compression load measured between the pelvis and the lumbar spine of the ATD may not exceed 1,500 pounds.
Footnote 2
FAR 23 Section 785a
C208 basis:
(a) Each seat, berth, and its supporting structure, must be designed for occupants weighing at least 170 pounds (or 190 pounds with parachute for seats in utility and acrobatic category airplanes), and for the maximum load factors corresponding to the specified flight and ground load conditions, including the emergency landing conditions prescribed in Sec. 23.561.
KODIAK basis:
There must be a seat or berth for each occupant that meets the following:
(a) Each seat/restraint system and the supporting structure must be designed to support occupants weighing at least 215 pounds when subjected to the maximum load factors corresponding to the specified flight and ground load conditions, as defined in the approved operating envelope of the airplane. In addition, these loads must be multiplied by a factor of 1.33 in determining the strength of all fittings and the attachment of‐‐
(1) Each seat to the structure; and
(2) Each safety belt and shoulder harness to the seat or structure.
(c) Compliance with the following requirements must be shown during the dynamic tests conducted in accordance with paragraph (b) of this section:
(iii) Compliance with the HIC limit must be demonstrated by measuring the head impact during dynamic testing as prescribed in paragraphs (b)(1) and (b)(2) of this section or by a separate showing of compliance with the head injury criteria using test or analysis procedures.
Footnote 3
FAR 23 Section 855a
C208 basis:
No requirement at that time
KODIAK basis:
(a) Sources of heat within each cargo and baggage compartment that are capable of igniting the compartment contents must be shielded and insulated to prevent such ignition.
(b) Each cargo and baggage compartment must be constructed of materials that meet the appropriate provisions of Sec. 23.853(d)(3).
Footnote 4
FAR 23 Section 1309
C208 basis:
No requirement at that time
KODIAK basis:
(e) In showing compliance with this section with regard to the electrical power system and to equipment design and installation, critical environmental and atmospheric conditions, including radio frequency energy and the effects (both direct and indirect) of lightning strikes, must be considered. For electrical generation, distribution, and utilization equipment required by or used in complying with this chapter, the ability to provide continuous, safe service under foreseeable environmental conditions may be shown by environmental tests, design analysis, or reference to previous comparable service experience on other airplanes.
Footnote 5
FAR 23 Section 1309, 399b, 677, 851
C208 basis:
No requirement at that time
KODIAK basis:
(e) In showing compliance with this section with regard to the electrical power system and to equipment design and installation, critical environmental and atmospheric conditions, including radio frequency energy and the effects (both direct and indirect) of lightning strikes, must be considered. For electrical generation, distribution, and utilization equipment required by or used in complying with this chapter, the ability to provide continuous, safe service under foreseeable environmental conditions may be shown by environmental tests, design analysis, or reference to previous comparable service experience on other airplanes.
(b) Each dual control system must be designed to withstand the force of the pilots applied together, in the same direction, using individual pilot forces not less than 0.75 times those obtained under Sec. 23.395.
(d) It must be demonstrated that the airplane is safety controllable and that the pilot can perform all maneuvers and operations necessary to effect a safe landing following any probable powered trim system runaway that reasonably might be expected in service, allowing for appropriate time delay after pilot recognition of the trim system runaway. The demonstration must be conducted at critical airplane weights and center of gravity positions.
(b) Each dual control system must be designed to withstand the force of the pilots applied together, in the same direction, using individual pilot forces not less than 0.75 times those obtained under Sec. 23.395.
(a) There must be at least one hand fire extinguisher for use in the pilot compartment that is located within easy access of the pilot while seated.
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Kodiak - SUV with a mission. Backcountry Traveler or Humanitarian Hauler, Quest's Kodiak Does it all.
«Аэро-Джип с Миссией. Рабочая Лошадка, Путешественник в глушь и экзотику или гуманитарный транспортник -Кодьяк от Квеста»