Cessna made an entry in the light-twin market with Cessna 310 in the late 1954. Piper had entered this market just a year earlier with Apache equipped with only 150 horsepower engine a side.
The young years of Cessna 310 were long and fruitful, before its market share started declining during 1980s.
Through a production span of 28 years, the 310 developed from a five seater with pressurized carbureted engines to a high flying turbocharged six seater. It was also certified for known icing conditions.
The landmark twin from Cessna also included the bigger turbocharged model, the Cessna 320 launched in 1963 and the pressurized 340.
During the long life of the airplane many changes were made to it, which provided a number of choices to the buyers of 310.
Budget minded people can enter the world of twin engines with a relatively inexpensive early 310. The age of early Cessna 310 is more than 60 years which raises maintenance concerns and purchasing a 1950 or 1960 model chancy.
In case you are a big fan of old and complex airplanes, than 310 will be a good choice for you, provided you are able to foot the initial maintenance bills.
One should remember here that the cost of maintaining an aircraft such as the Cessna 310 depend on the price of parts and its health rather than the price of purchase.
At the other end of the spectrum, the latest models of 310 can be taken up to perform transportation duties as they are as good as new models and the price is an indicator of this.
Why was there an change in line of Cessna 310?
One of the main reasons for this change was the horsepower. The first Cessna 310 started with pressure carbureted O-470 Continentals which provided 240 hp of power. In the next C model, launched in 1959, the 310 was installed with real fuel injection and an extra 20 hp of power on both sides.
Different variants of the IO-470 were used in the 1975 models in the 310Q. The IO-470 has been a dependable and trustworthy engine as a whole and has performed to its promise in the 310. mechanics and owners rarely had any complaints with the 470s.
The service difficult reports filed for the 470 installed airplanes have been comparatively lower than the TSIO-520 and IO-520 versions. Bigger engines from Continental were installed on the 1975 R model. It is a bit dissatifying to note that makers of Cessna 310 increased its power only by 45hp on both sides in its lifetime.
When compared with light twins from Beech, which started with 180 hp Lycoming in the Travel Air and expanding to a pair of turbocharged 380 hp monsters in the 56TC, Cessna 310 is left way behind.
Fuel Tanks in the Shape of a Fish
There have been variants in 310, which may take you in another age of airplanes.
The vessels positioned at the end of the wings can carry 50 gallons of fuel each. These tanks on the wing tips became hallmark of the twin Cessna.
These tuna tanks were there in the 1963 G model and were called “Stabila Tips” with an upward cant. The cantered tank imparted additional wing dihedral and presumably improved lateral stability.
The wings of the Cessna 310 had nearly 300 pounds of avgas and some help was needed in this department. It can be said that the airplane has significant roll inertia.
As was almost done to all its models in the 1950s and 1960s, the Cessna 310 was installed with a swept vertical final through the 1959 model in place of the upright tail.
It is not just the tail, but the shape and size of nose of 310 was changed to make it look like Pinocchio. One more seat was added by enlarging the cabin with the 1963 310H. During this changeover, the windows were added and lengthened.
Another major change was seen in the 1964 I model. The over wing augmenter tubes were replaced with the conventional exhaust plumbing. The exhaust gasses from the augmenters were directed to create suction for cooling air. It was considered that cooling will improve at high power as there will be more suction.
There was no problem in this system, however, the exhaust gases wreaked havoc on the wing structure as they are quite corrosive. There was substantial corrosion in the many early 310 at the aft spar and wing skins.
In case such such shortcoming go unnoticed at the time of pre-purchase inspection, the new owner of the Cessna 310 will feel a bit blue.
How about Flying the Cessna 310?
It is a pleasure to fly the Cessna 310. One of the biggest achievements of Cessna has been in making transition up the line quite smooth for pilots.
It is easy to move to 310 from other Cessna’s. It just has an extra weight and more speed. The aircraft has longitudinal stability, its roll is lightest, pitch response is heaviest and has good stick force per G.
Pilots who have been flying other light twins will find the 310 a big step up. When compared with Travel Air or Apache, this airplane will be more substantial and much larger.
Pilots who will move up the Cessna line, such as from C 210 to C 310 will find the controls heavier, higher approach and landing speeds and higher wing loading.
Moving from a complex single to C 310 is bigger than a move from a Bonanza to a Baron.
What About Cessna 310 on One Engine?
The performance of Cessna 310 with single engine is reasonably good. However, the performance of some light twins are much better with one inoperative engine.
Early 310s have the ability to climb at 415 feet per minute at maximum gross weight (4,700 pounds in the 310B) on one engine. As weight is increased, climb rate decreases on single engine.
The T310R can climb at 390 FPM at its maximum weight of 5,500 pound at sea level with on feathered.
The service ceiling of 310B on one engine is 7,700 feet, which is improved to 17,200 feet in turbo models such as T310R.
Handling the Cessna 310 on a single engine can be a bit difficult for new pilots particularly near the runway. First thing, the all-electric gear will take some time to stow. Second factor is the fuel tanks mounted on the tip which creates a natural rolling tendencies.
A pilot will get really busy soon after engine failure. Pilots those who have experience on 310 explain that one should minimize the aileron inputs to prevent 310 from rocking.
Overall, a Cessna 310 is a beautiful flying machine. It is an immovable object in turbulence, although a bit stiff. According to 310 experts – pilots should deploy the landing gear and split flaps together. This will offset the nose-pitching up.
Strong, Sturdy and Speedy
One of the strongest selling points of the 310 has been its speed. The two 240 ho engine can push the airplane at 183 knots at 7,500 feet (burning 25 gallons in an hour at 70% power). With both engines the aircraft can climb at a rate of 1,600 FPM from sea level.
Additional weight is compensated by the extra power. The Q model has 260 hp on both sides which can take the aircraft to 186 knots and can climb at the rate of 1,495 FPM (at 71%, 7500 feet consuming 26.5 GPH). It is a good performance as Q models have 600 pounds more gross weight. The final version with 285 hp can touch 190 knots burning 29 GPH.
The turbocharged Cessna 310 are much faster, at 10,000 feet it can cruise at 198 knots and at 20,000 feet it can cruise at 220 knots (at 74% power in both cases).
The Complex Fuel System of Cessna 310
The engine compartment of the different 310 are pretty straightforward, however, complexity arises when we look at the fuel system.
The 50 gallon tanks on the tip are the only containers of fuel. In the event of a crash they are designed to shear off. Till the 1958 B model, fuel only used to be in the tips.
Later on, auxiliary tanks were installed in the wings, which provide an extra 40 gallons of fuel. Wing locker tanks having a total capacity of 20 gallons in each were available as options in the 1967 models.
Either one or both of the locker tanks can be ordered.
In 1973, the capacity of auxiliary tanks were increased once again to 63 gallons. This means Cessna 310 was available in 100, 140, 163, 183 or 203 gallons capacity. There were 10 fuel pumps and six tanks available in long range Cessna 310.
Is There Too Much of Confusion?
Is it too much for you to handle? Well, what will happen when you will have to manage the tanks. New fliers of Cessna 310 may get caught in two different situations.
Firstly, more fuel is sucked by all 310s than that can be used by the engines. There is a return line from the engine compartments both in the fuel injection and pressure carburetor models. However, this connection is able to return fuel only on the same side as the engine to the main tank.
This means that half of the fuel will be moving on the same side main whether the fuel is used either from the auxiliary tank on the same side or from the opposite side from the main tank. Any excess fuel is sent overboard when the main reaches capacity from the return fuel and it is not possible to cross-feed auxiliary fuel.
Second system is in the form of locker-tank scheme. In most of the airplanes just one such scheme is installed and the engines cannot consume its content directly. The locker fuel has to be pumped to the corresponding main tank.
When the locker is on the right side, nearly 20 gallons of fuel need to be drawn from the right main to create room for the locker fuel. Now you will have to minimize the lateral imbalance and cross feed the left engine.
To properly understand and get fine tuned with the working of this complex fuel system will require time.
It is worth taking a look at the service difficulty reports. It has been found that the gear system of the Cessna 310 and can be described as its Achilles’ heel.
From the 225 SDRs that will looked into of nearly 150 different aircraft, more than 40 of them were related to gear alone. Problems were related to actuator rods, support structures, cracked or broken mounts, shock struts, door hinges and actuators and bell cranks.
Parts failures resulted in a number of complete or partial gear collapse. What is more, more than half of these cases were related to main gear. The lesson should be kept in mind.
The gear system of any Cessna 310 should be thoroughly and carefully inspected before making a purchase. Many of the early airplanes come fitted with retrofit Cleveland brakes. It may be a bit troublesome and expensive to maintain the original Goodyears.
According to Cessna 310 support groups and owners, it is easy to find the parts for airplane, however, just like with most other models these days, the cost can be too much.
Ending with a good note, apart from the gear troubles, there is not much of a problem with the Cessna 310. This can be really surprising to some considering the complexity of the machines and the overall age of the fleet.