Designed for farmers who have reached the limits of harvesting capacity from straw walkers, but still want decent straw quality, New Holland has revealed a new threshing development for its mid-range combines. Alex Heath reports.
Blending the manufacturer’s twin rotor and conventional harvesting systems into one package, New Holland has launched a new mid-range combine that sits in between its CX straw walker range and twin rotor CR range.
Boasting a 25 per cent higher throughput than conventional combines in this power segment, the new CH, which stands for crossover harvesting, is initially a one model range, being the CH7.70.
The company says the new combine is ideally placed for those users who are reaching the limits of harvesting capacity with its CX straw walker machines, mainly as a result of green straw. However, straw walker users are typically conscious of straw quality and hesitant over opting for a pure rotary machine. In response to this, the manufacturer says straw quality coming out of the CH is very similar to that of a straw walker.
While the combine is built using the chassis and side panels of the CX6.90, performance is at comparable level to the manufacturer’s narrow body rotary machines, namely the CR7.80, it says.
Two machines were running in the UK last harvest against its mid-range CX combines. Where the mid-range CX’s were harvesting 28t/hr, the manufacturer says the CH was surpassing 40t/hr with little noticeable difference in straw quality and a better grain sample.
Key to the new model is a 607mm diameter, 1,560mm wide heavy-duty threshing drum positioned in front of the two longitudinal rotors. With eight rasp bars and a new heavy duty hydraulic variator, drum speed can be matched to the crop and field conditions from the cab with a range of 400 to 1,200rpm.
Encasing the threshing drum is the manufacturer’s Opti-Thresh system, enabling adjustments to be made based on crop conditions and maturity by repositioning the rear concave section. The variable geometry concave reaches a 121 degree wrap angle when fully closed, while fully open it is 85 degrees. This allows for riper crops to be harvested with less aggression, preserving straw quality. The manufacturer says about 80 per cent of grain separation should occur in this drum.
Crop passes through the four-paddle beater which adds a further separation element, while lifting the straw to enter the rotors at the top, increasing efficiency, the manufacturer says. Grain quality is also a priority, so reducing cracked grains is imperative, it says. As a result, the combine does not include a rotary separator, unlike its straw walker cousins. The manufacturer says this omission nearly puts the CH on par with the CR, where cracked grain percentage is targeted to be under one per cent and significantly better than the CX machines in this department.
Twin rotors are the last chance to separate the grain, which at 533mm in diameter are just 26mm smaller than the rotors used in the firm’s flagship CR10.90. At 3,450mm long, the rotors offer 2.9sq.m of separation area, the largest for a combine in this size range. Rotors can be run at two speeds (400 or 700rpm) depending on the crop. Offering a 93 degree wrap, eight of the 10 concaves are removable for cleaning and maintenance, while a flap at the end of the rotors can be opened and closed as per the crop, useful when harvesting rapeseed to stop pods and short straw overloading the cleaning shoe.
Cleaning is taken care of by the firm’s same ‘Triple-Clean’ cascade system used on the CX5 and 6 models. With three drop points, the fan has three opportunities to remove short straw and chaff from the sample before it reaches the main sieve. The fan automatically adapts its output depending on the gradient of the path being travelled; slowing when going uphill and speeding up when going downhill, with a speed range of 530 to 1,200rpm.
The company has also included a hill compensation element to the sieves, eliminating the effect of side slopes by 25 per cent, it says. The system also calibrates sieve action based on fan speed and grain size to determine the optimal throwing angle. Total cleaning area under wind control is 5.21sq.m. The manufacturer’s Laterale hillside version is available, claimed to counteract the effect of side slope of up to 18 per cent in gradient.
Dealing with chaff residue is a pair of hydraulically-driven spinning discs, which can be set to spread away from the swath, or bury it under the swath, resulting in cleaner, less dusty straw. If straw chopping is required, the chopper slides forwards with an electric motor.
A 9,300 litre grain tank features, which can be emptied in under 93 seconds thanks to an unloading speed of 100l/sec. Unloading augers up to 6.4m can be specced.
Power comes from an 8.7-litre, Stage 5, FPT engine, developing a maximum 374hp. The three-speed transmission has a maximum road speed of 30kph.
The CH7.70 can be equipped with a range of the manufacturer’s Varifeed headers, up to 9.15m, including a brand-new 8.53m Varifeed version specifically developed for this range and an eight-row maize header. The front face of the feeder housing can be mechanically adjusted to ensure alignment with the header.
The CH is fitted with the firm’s latest Harvest Suite cab, boasting 6.3sq.m of glass and a 73dB noise level. A dark interior reduces windscreen glare at night, while up to three cameras can be added externally. The manufacturer’s IntelliView terminal displays all harvesting parameters, while all controls including the CommandGrip drive lever are on the armrest.
New Holland Agriculture offers a wide range of machinery whatever you cultivate, raise, harvest, bale or transport, New Holland always has the machine and equipment that fits your needs like a glove.
Tractors from 27 to 435hp, best-in-class conventional and rotary combines, round and big square balers, profit-raising telehandlers, a complete choice of tillage and grass equipment, and a selected offering of construction machines, able to perform a wide range of agricultural applications.