From the Cockpit

The Model 33s flown are of early to late sixties vintage. However, the qualities that endear the A36 to pilots and passengers alike extend much farther back and the reputation the first Model 35 Bonanzas established in the late 1950s was reason enough for the company after years of development to have the Bonanza name on four models. Tracing the genealogy of the Bonanza and deciphering the maze of marque letters and numbers is worth recounting here.

Bonanza Evolution

The prototype of the Model 35 Bonanza first flew on December 22, 1945. In the terminology of the day it was described as a retractable landing gear four seat cabin monoplane of semi-monocoque construction with flush riveted metal skin and a butterfly-type tailplane of 33 degrees dihedral. As it is now known, the V tail has remained a unique characteristic in this class of aeroplanes. The Model 35 went into production in 1947 with the flat six Continental E165 engine, developing 165hp (123kW) at 2050rpm. The landing gear retraction system was all electric. From the start performance figures were impressive: maximum speed 160 knots at sea level, cruise speed 152 knots on 115hp at 10,000 feet, range 650nm at 143kts and 10,000ft on a fuel capacity of 40 US gals; useful load 480kg (10601b) for an MTOW of 1156kg (2550lb).

The type quickly emerged as a breakthrough in personal transport efficiency using light aircraft. The early drawbacks were seen by Beech to be range and power deficiency. The former was rectified by the introduction in 1948 of auxiliary fuel tanks of 20 US gal capacity to be carried in the baggage compartment. The progress at Continental Engines was reflected by the installation of sequential engines in the Bonanza. The 1948 production model was powered by the E185-1, rated at 185hp (138kW) at 2300rpm for one minute for takeoff. For this aircraft an increase in empty operational weight caused a loss in useful load. This was restored in 1949 by structural reworking, albeit with a slight loss of cruise speed and the model was designated the A35 Bonanza. Beechcraft then began running through the alphabet with each engine or structural change. Maximum power increased to 250hp (186kW) in 1960 in the M35 Bonanza, while fuel injection was used for the first time in the 1959 J35.

However, Beech used the power increase to improve performance and not load capacity: max continuous cruise speed increased 14%, SL ROC 23% from 950 to 1170fpm, but useful load from only 1070lb (485kg) to 11181lb (507kg).

In 1961 the Model 33 Debonair went into production. With the wings and fuselage of the J35, the Debonair had a conventional tailplane and a new engine, the six-cylinder 225hp (168kW) Continental IO-470-J- basically a tradeoff of some performance for useful load increase, not just a conventional tailplane.

The direct forebear of the well known V35B, the S35 received FAA type approval in January of 1964. This model was powered by the 285hp (213kW) Continental 10-520-8 and had either leading edge tanks of 50 US gal usable capacity or long-range wing tanks of 80 US gal usable. At 75% power cruise, speed at 6500ft was 178kts and range with reserves 995nm (long-range tanks). The cabin had been finally lengthened by 0. 48m to 2. 59m.

Following type approval in December 1964, the C33 went into production in 1965. With the 225hp (168kW) IO-470-K, it had a 23kg improvement in MTOW over the 833, the S35 fuel tanks and larger rear window. The 285hp (213kW) 10-520-8 powered C33A followed in 1966/67; with the same engine, the top-of-the-line Models 33 and 35 had evolved to being similar aircraft, the only significant configuration difference being the conventional and V tails respectively. The fact that Beech considered the Model 35s to be nearing a development plateau was reflected in the jump to the designation V35 for the 1966 model, which had MTOW increased to 1542kg (3400Ib).

The 33s were renamed Bonanzas in 1967. 33 Series aircraft in production during 1968 were the E33, E33A and E338, E33C (E33 and E33A strengthened for the aerobatic category respectively). The 1970 F33A had a MTOW the same as that of the V358, 1542kg. The F33 (IO-470-K powered) was discontinued during 1971, in which year also the F33A cabin length was increased 0. 48m to be the same as on the V35B.

In mid-1968 a new model, the A36 Bonanza was introduced.

Powered by the same 285hp engine as the V35, the A36 received type approval in the utility category at MTOW 1633kg (3600Ib). Cargo-carrying operations were facilitated by the installation of double opening doors on the starboard side of the aircraft. The contemporary A36 has a cabin length of 3. 84m (including an extended baggage compartment of 400Ib capacity), over three-quarters of a metre longer than that of the V358 and F33A.

The V35A was turbocharged in 1968/69 but was discontinued soon after. The A36 was turbocharged in 1981, the A36TC had its wingtips extended 0. 6m the year after (B36TC), but whilst many Bonanza fliers would no doubt have liked to see the aircraft pressurised, Beechcraft elected to remain outside the pressurised piston-single field, going instead considerably upmarket with the turboprop-powered Lightning, before it too stagnated in the rationalisation of the early 80s following Raytheon’s purchase of Beechcraft and a deepening GA recession.

Flying the B33

The B33 I flew on several flights was fitted with Brittain Industries wingtip aux fuel tanks, raising total usable capacity from 50 US gal to 91. 8. However, they provide some inertia relief to the wing and the 833 thus fitted is certificated to an MTOW of 1429kg (3150lb) with tip tanks full or 1406kg (3100Ib) with tiptanks empty.

If there is one aspect to the flying _ controls different on the Bonanza than most other light aircraft, it is the operation of the trimwheel, which is located under the instrument subpanel to the left of the centre console. Movement of the wheel can be effected on the bottom of it only so that arm action is in the opposite sense to the stick pressure – one has to think in terms of rotational movement, rotating the wheel in the same sense as the required pitch change of the aircraft (palm upwards technique I find best). Nevertheless, the trimmer sense has been the cause of at least one accident that I remember.

Whilst on ergonomics, other irritating items are the positioning of the gear indicator lights and the positioning and operation of the fuel selector valve, which to be sure requires bending forward to see, difficult with belts tightened in turbulence or disorientating at night or in IMC; further the selector location makes itself susceptible to inadvertent knocking out of position by foot movement.

On takeoff, acceleration is brisk and lift-off control positive.

The B33 however is noisy. Airborne, flying control feel and response is pleasurable. With a down spring the elevator is firm. Roll control and response is particularly satisfactory. However, the lowly measure of lateral stability tends to affect heading maintenance on instrument approaches and was reason enough for Beech to install a rudder/aileron interconnect spring to enhance the lateral stability (with substantial control deflections only). Spring bias does provide a means for adjusting the lateral trim in flight however; on the tip tank-fitted B33, imbalance could occur when feeding from the tip tanks because the return line from the fuel pump routed through the selector valve, returns fuel to the port main tank only.

The high gear extension speed on 143 KIAS, when required, facilitates high speed descents and entries into the circuit pattern. The flap extension rate is rather slow however and necessitates thinking ahead of the aircraft’s height and speed situation.

Flying the E33A

On the other hand the E33A is powered by the 285hp (213kW) IO-520-B, for a mere 150lb increase in MTOW over the tiptanked 833-giving an increase in power-to-weight ratio of 21%. The result is that the E33A has much more get up and go; with gear up after lift-off, it treats the shackles of earth disdainfully. Once at altitude, it is a good25kts faster than the B33-a flight plan TAS of 165kts at 718000ft for 65% power cruise (full throttle and 2330rpm at this altitude), and a corresponding fuel flow figure of 14 US gal/hr has seemed to make the tanks honest. As with the B33, the handling qualities of the E33A are pleasant, particularly lateral response.

Concerning loading ability, that of the Bonanza is one of the aircraft’s strong points. This particular E33A had an empty operating weight of 938kg. Fitted with long-range fuel tanks of a usable capacity of 80 US gal, with full fuel and four on board, 30kg could still be carried to make up the MTOW, 1497kg, with the resultant centre of gravity being well in the range. This compares to many other light aircraft where passengers and/or baggage must be traded with fuel load, or the fuel load itself is limited by the CofG range.

Bonanzas in Australia

So what of the Bonanzas in Australia? This country has taken its share of the more than 10,000 produced and they have sold well in the Australian environment. Our Sept ’86 issue Australian Aircraft Census (p108) indicated that there were some 217 A33s, 35s and 36s on the DofA Register at mid 1986. With airframes of proven durability, used prices reflect the longevity of the aeroplane as well as its popularity. Nevertheless, the market reflects a wide price range, depending on the marque, hours and avionics. On and off, the Bonanza’s V tail has come under scrutiny for airworthiness considerations. The FAA finally acted last year, by slapping a speed restriction on the aircraft until the tail structure was re-analysed. Basically, the FAA has questioned the adequacy of the (conventional) airloads data as applied to the V tail surfaces – particularly concerning strength at high speed. Beechcraft responded with a load analysis (probably computational, such as the vortex lattice method) and test programme, with Company President Walsh expressing confidence (1986) that the strength could be validated.

It is unclear whether the FAA’s action has affected local aeroplane prices. For the buyer, the selection of Bonanzas/ Debonairs on the market is quite wide. Considering Debonairs firstly, mid 1960s aircraft, for example the C33, with good hours to run (800 to 1200) list for about $48,000 if NVMC equipped and $53-55,000 if LIFR equipped. For an aircraft with a major due or a CofA renewal, a price in the low $30,000s may be sought after, clearly requiring substantial and immediate further expenses. The prices of late 1960s V tail (Model 35) Bonanzas are substantially more -approaching $70,000; for example a 1969 V35A of moderately low hours, 3600, with 900 to run and full IFR avionics, including Century Ill NP was recently listed at $67,500. Later Model 33s, such as the E33A, LIFR equipped at least, can list at substantially higher prices -well into the $70,000s.

To complete the picture, mention should be made of the used A36 market. The A36 is by far the most numerous used Bonanza and consequently presents the purchaser with the widest selection. Market prices correlate most closely with the total flying time of the aeroplane and vary from about $140,000 for 1000hrs TT reducing to $100,000 for 4000hrs TT -with an allowance of $10/ 20,000 for full and updated IFR avionics; these hours, for such personal/corporate use aeroplanes correspond approximately to 1982 to 1972 years of manufacture respectively.

Consideration can also be given to purchasing and importing a Bonanza from say the UK where prices are well below Australian: vintage Model 35 Bonanzas list for around £12/15,000. It is most important though if pursuing this tack to have or obtain a clear steer on the CofA and required mods for the Australian regis­

Next Issue: we analyse the world’s most popular light aircraft, Cessna’s evergreen 172 Skyhawk. Don’t miss it!