The method and apparatus for synthetic experiment and study of the tractive characteristics of a wheel under seven use conditions were described.
1. The apparatus of test method which a wheel rolling around a fixed axle on a travelling soil bin was produced, and the method which reappears all seven use conditions of the wheel were described.
2. The relationshipes between slip ratio, relative speed and travel reduction ratio (=rt) were explained. and it was described that the travel reduction ratio is zero when the tractive force(=drawber pull) is zero, and this point must be standard point when the characteristics of a wheel are discussed as a whole.
3. It was proposed that a wheel must be classified into a driven wheel and a towed wheel, still more by seven use conditions as following: the former is classified into a completely slipping driven wheel with drawbar pull, a driven wheel with drawbar pull, a driven wheel without drawbar pull and a driving towed wheel, the latter is classified into a driving towed wheel, a free rolling towed wheel, a braking towed wheel and a completely braking towed wheel.
4. The relations between the test method by a travelling wheel on fixed soil and the above test method were made clear, and it was indicated that the using conditions by a travelling wheel method are reappeared by use of above test apparatus, and the same conditions are obtained by both methods.
5. The comparision between the method in which rotating speed (=n) of a wheel is constant and its travelling speed (=v) is varied and the other method in which v of a wheel is constant and its n is varied, and the studing method of the characteristics under all use conditions of a wheel by one experimental and considerational method, and then the method by which obtain the F-n diagrams at the v of a wheel is constant and its n is varied from the F-v diagrams at the n is constant and v is varied were described.
It was indicated that the range of F>0 and driving torque =T>0 in the n is constant and the v is varied method for the driven wheel and the range of F<0 and T<0 in the v is constant and the n is varied method for the towed wheel should be respectively used.
6. It was described that the torqueless travel reduction ratio is zero when the driving torque (=T) is zero, and this point must be standard point in the case of only the towed wheel, and the relation formulas between each travel reductions at the F=0 and T=0 were obtained.
7. Some efficiencies and coefficients in each case of driven and towed wheel were defined.
8. The soil reaction and the balance of forces and moments in each of seven use conditions of a wheel were discussed, then the method was shown to find the soil reaction force (largeness, direction and position), running resistance R and the reaction point of resultant soil force to the wheel surface from the measured weight on the wheel axle (=W), the tractive force (=F) and the driving torque (=T); moreover the possibilities of the application of this studing method were described.

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To take the place of the driving wheels of 4-wheel tractor, the crawler has been set recently and morover the rubber crawler has been manufactured on accunt of making up the running faults of the iron crawler.
On accunt of comparing with the performace of three running types (pneumatic tyre, iron crawler and rubber crawler), the tractive performance of them have been measured.
On concrete road, the each drawbar pull of three types increases rapidly untill slipage 30% but at more than 30%, only the drawbar pull of the rubber crawler maintainn a certain increasing slope.
On hard soil-road, the each drawbar pull of three types increases gradually in proportion to slippage and the mutual difference of them is not clear.
On glass land, both the iron and rubber crawlers indicate nearly equar high tractive performance and they are superior 25%-30% to pneumatic tyre in coeff. of traction. But the each drawbar pull of three types scarcely increases at more than slippage 30%. Above-mentioned results are summarized and shown in Tab. 2.
It is found from Tab. 3 that the curves of force ratio tend to be similar to those of coeff. of traction and it is ascertained by Tab. 4 that the maximum drawbar HP of the pneumatic tyre is less than that of the crawler types on all tentative road.
On the whole, it has been definitely know by this test that the rubber crawler has always the best tractive performance on all tentative roads.

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To Study on the effect of the differential gear for traction performance of tractor, we gave the weight difference on the wheels of each side of the differential gear for light compact car, and also let the wheels have deflection angles for the running direction, likely as the report 2 of this series. It is the same also that we tested about 2 features of weight difference, that is, heavier or lighter downhill wheel than uphill wheel.
(1) Pulling the test tractor with another one, the coefficient of traction resistance is not influenced by the differential gear, being due to its inner friction.
The coefficient of side force decleases with the increase of weight difference under the condition of heavier downhill wheel, but increases under the condition of heavier uphill wheels. It is due to the force of the uphill wheels to apt to run to the travelling direction.
(2) Driving by himself pulling some load, not light load, the coefficients of traction force, side force and driving force decrease with the weight difference, and yet under the heavier downhill wheel, reduction of the running speed is larger, and then the traction efficiency is inferior compared with the condition of heavier uphill wheel. These are due to the working of differential gear.
Now, we can calculate the traction force and the driving force etc. by using the equations in this report. And from the test results, we can say that the weight difference on the each wheels must be kept as less as possible, for the purpose of the larger traction force. It is the same advice as the results of the report 2.

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Drawbar pull of farm tractor on plowing is decreased by the influences of the weight and surface difference between the both side driving wheels and the inclination of the turning plane of its wheels. It is moreover influenced by the differential working, but it is recovered by the differential locking as Fig. 2 indicated.
The reason is that magnitude of the drawbar pull is decided by the weight of the heavy side driving wheel in the differential locking, against by the light side driving wheel in the differential working.
Then, differential locking is useful for increasing the drawbar pull and reducing the wheel slippage.

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This paper continues to the similitude study of the slip-sinkage phenomenon of grousored plates (I).
The correlation between the distortion factor (r=π′_9m/π₉′) and the prediction factors (δ_s=π_1a/π_1am and δ_d=π_1b/π_1bm) for set 2 are shown in the following equation (Table 2.): δ_s=r-0.979, δ_d=r^0.350 when π₆=0.0034 and π₈′>2.4.
Slip sinkage increased and the draft pi term H/pl² decreased as the width of the plate decreased. (Figure 5.)
Both slip-sinkage and H/pl² increased as the grouser height increased. (Figure 8.)
Slip-sinkage decreased and H/pl² increased as the inclination of plate was increased to a 20° slope.
The results of this study was applied to the slip-sinkage of Sibaura K-20 tractor and predicted it with considerable accuracy.
Excavation should be separated from slip-sinkage, which was discussed with viewpoints of forces acting on the soil wedge beneath a plate and soil structure. (Figure 11 and 12.)

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The characteristics of the torque control system were investigated with the method of the spectral analysis to the random inputs having the short period of time.
(1) Tillage torque of the rotary tiller is the random process with the periodical variation components.
(2) It has the peculiar variations according to each arrangement of tines and tillage pitch. As the frequency of the rotary revolution is fo c/s, they are the harmonics of the frequency fo, 2fo, 3fo and 4fo.
(3) The power spectrall density in 4fo is the greatest for the sixteen tines arrangement but in fo greater than in (4) fo for the twelve tines arrangement.
(4) The wave form of the tillage torque was concluded by the theory of the tine arrangement and the driving procedure.
(5) The system may control desirably the tillage depth in accordance with the changes of the tillage pitch.
(6) As the gain to the inputs with the higher frequency is lower, the system is stable enough to do the tillage works.

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1) The authors made an instrument to copy the shape of field-surface. We call the instrument “field-surface copying instrument.” The instrument has 50 spokes and the maximum measuring range is 100cm in length.
The use is as follow: Touch the lower sides of 50 spokes on the face of the field and read the upper sides of 50 spokes by a scale or photograph them. As stated above, the use is easy and the date is accurate.
2) We set up three methods to express the level of field-surface. They are standard deviation (δ^mm), level degree (D^mm(n%)), level per-centage [n%(D^mm)]. Every method was exact and useful.
3) Swelling percentage of field-surface after tillage can be measured accurately by the field-surface copying instrument and porosity can be calculated easily by the swelling percentage of field-surface.
4) The shape of field-surface after each tillage can be observed immediately by the field-surface copying instrument.

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In order to find the more economical method of evaluating the quality of agricultultural products, measuring physical properties of the products was proposed.
Results from data obtained by measuring bending, compressive and interpenetrative strength of cucumber and tomato under preservation revealed that;
1. Within 30hrs after harvest, strong correlation between measured physical properties and quality deterioration of both products was not visible.
2. As the storage time advanced, quality deterioration become more significant, probably due to riping process. Severity of deterioration were expressed in term of physical properties ratio. Limit value of this ratio for both products under edible conditions were:
(a) for cucumber
Flexural rigidity EI/E₀I₀=0.70
Bending deflection δ/δ₀=1.10 1.15
compressive Strength P/P₀=0.80
Shearing strength of epicarp (interpenetrative strength):
with A type plunger P/P₀=0.05
with B type plunger P/P₀=1.02
(b) for tomato
compressive strength P/P₀=0.60
Shearing strength of epicarp (interpenetrative strength):
with A type plunger P/P₀=0.80
with B type plunger P/P₀=1.25
3. For cylindrical products, bending strength might be useful as measuring items for quality evaluation, while spherical products of equal size, compressive strength is suggestible. However, for spherical products of nonequal size, interpenetrative strength with B type plunger is more preferable than compressive strength.
4. Besides the shape, shearing strength of epicarp might be useful as property to evaluate the quality of the products.

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The effect of packaging, cool storage and O. E. D, treatment on the fall of physical properties of grapes, especially the fall of grain, were investigated and the following results were obtained:
1) Moisture content of the stem of grapes less than 63 percent results in the falling-off of grain during distribution process (Fig. 2).
2) The falling-off of grain of grape-bunches due to the vibration decreases with the treatment of polyethylene packaging and cool storage.
The fall increased remarkably after the cool storage followed by warm storage or retail sale condition non-cooled (Table 3).
3) Loss of moisture content of bunches is diminished by polyethylen packaging and cool storage (B, C, E in Table 4).
Moisture content of bunches diminished remarkably due to the cool storage followed by warm storage (G, H in Table 4).
4) Correlation does not exist between the acidity and falling-off of grain.
5) Half cooling period of 12 minutes is obtained by air blast cooling of grape bunches.
The cooling rate is influenced by many factors such as location in the container, direction of air blasting on the fruit, air velocity, etc.

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The authors investigated heart rate and relative metabolic ratio of five adult male subjects practicing various tasks (Tab. 1). There was found very close positive correlation between heart rate and relative metabolic ratio (Tab. 2). The relation of these two indexes could be shown by a simple equation y=ax+b (x: heart rate, y: relative metabolic ratio). Numeral values of coefficients a and b, however, not only varied with every subject, but also differed from those obtained from the previous experiment by a tread-mill. That is, at a certain work intensity of a certain subject, heart rate of this experiment was a little more than that of the previous under the condition of relatively higher intensity, and less under lower intensity. These differences seemed to be chiefly due to the intensity of nervous load, which was related to autonomousness of the subject's exercise affected by various experimental conditions.
It may be concluded that the mathematical conputation of relative metabolic ratio based on heart rate was proved to be not so much precise. But, with pretty wide latitude, heart rate is proportional to the intensity of work load, and reflects the change of intensity even during a short time more easily than relative metabolic ratio.
The authors intend to investigate heart rate of various jobs and work elements and to point out problems to be studied for the reduction of work loads, in and around the livestock barn.

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Reclamation of tropical wasteland is said to be easy on account of the shallow root, so we tried to reclame by Chain High Ball.
Maximam theoretically pull down force of Chain High Ball can reckons to be 36, 361.2kg under the condition that drawbar pull of one tractor is 20, 000kg, drawing road width-4.5m, working width-20m, and running resistance find expression in W=(Gc+Go) (μd/2R+f/R) (kg).
Chain High Ball is drawn by tow angle dozer which maximam horsepower is 225PS. Working width is from 20 to 25 meter
In the place lying scatted tree diameter is measures over 0.4m, two tree dozer was necessary to help at the backward position.
Rate of work was 1.4 times as compared with habitual working method by angle dozer and tree dozer.
Rate of work is decided by many condition, such as working width under making sure circumstances of vegetation and topograpy, to dispose board and prop root of big tree previously, combination working of drawing tractor and backing up tractor and so on.
Therefore it is necessary high operation technic more than standard operation method.
Ball is necessary to keep pull down-point in high position. Diamater 2.45m∅ is temperately dimensions to pull down smoothly without rough clearing.
It is advisable that ball weight have light to reduce running resistance. But sometime tree do not be pulled down on the land perfectly, and lean on the tree of front side. In this case, Ball climb up those tree to break down, and must make from way. 6.02ton weight was suitable under the condition of the forest at Makariki, Indonesia.

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