When Danikel got to Master Wagon Works he noted the eight big wagons that were at various stages of assembly on the main floor with assigned crews busy working on them. He wondered where the Wind Waggon crew would gather for daily work assignments. Danikel did not immediately see his master machinist boss Artia or the team leader Mr. Smellows so he began asking team leads for the various waggon assembly teams. At the second waggon assembly area he learned that his new Wind Waggon team would assemble out in the old back assembly area in a few minutes, so he wandered out that way.
Danikel arrived just as Mr. Smellows was coming down from the supervisors work platform above the side of the main waggon assembly areas. The team was composed of eight others that he knew since working at the Works. They included Artia the master machinist, a good boss and very clever, Burgoris the other third class machinist apprentice, Alfire, a second class machinist apprentice, Boddia a general worker, Mikela another general worker, Ekelis a master wood worker, Penchist a third class apprentice wood-worker and Adlier a master general worker. Of course Mr. Smellows, the lead designer would provide the design details and generally supervise the work although he was on several other teams doing the same thing as well.
Rain was expected and it was known that this older back assembly area leaked and was drafty, not a very good omen for the importance of the new project in Danikel's estimation. Mr. Smellows signalled for the team to join him around a work table where the designer had just rolled out a couple of sheets of plans. Mr. Smellows momentarily blocked the view of his plans and signalled for quiet. Meanwhile the boss of the Works was coming down from the above work deck to join the team. Mr. Kellies had been boss since his father passed away, managing and owning the works as well.
Mr. Kellies moved to the front alongside Mr. Smellows and the team quieted down and paid close attention. The owner announced "This team is composed of some of the best waggon builders in order to tackle a new and innovative waggon motive power scheme recently devised by Mr. Smellows." He continued, "This team will have the privilege to be a part of a truly revolutionary waggon design and the opportunity to prove that waggons can be moved by means other than draft animals." Finally, Mr. Kellies concluded, "This work is revolutionary and gives Master Waggon Works a definite edge in future business affairs, so please treat all aspects of this project as most private, not to be shared outside this team."
There was some murmuring as Mr. Kellies walked back upstairs and Mr. Smellows hung his first drawing up for inspection by the team. There was an outburst of excited and bewildered talk from the various team members as Mr. Smellows smoothed down the drawing and turned to face the team. Mr. Smellows opened his remarks with "Boys, the problem with penetrating the grasslands is that draft animals are way too vulnerable to the big cats and we have tried everything to protect them to no avail." He continued, "We even tried, as you may recall, putting draft animals inside on a turntable device." He went on, "This sort of worked, however, the animals badly smelled up the interior and required way too much food and water to keep them healthy."
Mr. Smellows further stated, "The large bulky waggon we did for that experiment happened over 15 years ago and convinced our leaders that inside draft animals was not practical." He further stated, "We did learn however how to make various kinds of drive coupling devices some of which may be a strong assist on this project." He continued on."Instead of inside draft animals, on this project we will use outside wind sails mounted on a turntable." He also remarked, "The force of the wind on suitable sails can be in excess of the pulling power of draft animals when properly configured." Finally he stated, "Please look over the plans carefully and later we will have further sessions to understand the project work efforts." With that Mr. Smellows walked upstairs also leaving the team to ponder the design.
Remarks flowed like water among the team to the effect that sails mounted on a turntable seemed like a nearly impossible venture and might well prove once again an unworkable idea. Imagine taking mid sized sails from a ship, not one, but six of them, and keep control of them while they rotate around and around on a turntable. The turntable would in turn couple power through various belts, pulleys and gears to the wheels of the large waggon. This project was at this moment overwhelming in scope. The general consensus seemed to be this was a really risky idea.
Throughout the back and forth commentary, Artia remained silent and carefully studied the plans. Finally he made a point, "This seems workable provided we find a good balance for the turntable and of course use very strong sails to handle the higher winds that occur from time to time. We need to study this idea with some forethought. We have undertaken complicated waggon builds with protection turrets from the big cats all along. Altogether this new turntable effort should work provided we put the full effort and knowledge of our experts to work here. We are those experts."
It was soon lunch time. The rain had stopped so some of the team drifted out into the back compound sitting on various convenient spots. Danikel vaguely knew Alfire and Makela so he joined them sitting on a pile of lumber which wasn't too wet. Danikel took his lunch that his wife Masela had prepared and relished the possible contents as he knew she fed him well. During the eating silence was the rule so further conversation about the project was held off. Danikel knew that Masela would be asking about the project and usually wanted some details, probably to show him her interest in himself. He pondered what he might tell her. He decided that he didn't know much anyway other than the name of the project, so likely he couldn't add much to what he already had told her.
Eventually the eating slowed to a near halt and Alfire opened a conversation with "The sketch shows that the sail device on top is higher than the waggon is long. The waggon looked larger than the more or less standard Master Waggon Works model 1024 which is ten feet wide and twenty four feet long. He would later learn it is some 45 feet long and 14' wide with some overhang of the sail panel turntable. That means the height is so great there is no way such a waggon would ever go on the roads through the forested parts of existing trails. I wonder whether anyone would every want to buy one." Makela piped up, "I got the impression that the prime motivation was to explore the great grasslands where there are no height restrictions. I'm more concerned that our team knows nothing about rigging sails. We can readily buy sails, but we know nothing about the ropes and pulleys needed to move them about."
Alfire added, "I get the idea that each sail is pivoted separately. Each has it's own attachment point, and those are mounted part way out from the center mast. If the whole thing turns on the turntable bottom, than the sails and masts rotate around the center. I've seen rigged ships and there is no way the sails can rotate very far, perhaps no more than thirty degrees either side of center. With the sails rotating around the center mast the rigging must be very complicated. I sure have questions now for Mr. Smellows concerning how those sails are to work. "
Markela added, " I wonder too about the tendency to tip sideways under heavy wind. Ships have their bottoms filled with heavy boulders and such to help them resist tipping in the wind. How much wind is the waggon supposed to experience? "
Danikel couldn't comment on these matters as yet so remained silent hoping to learn. To himself he pondered why the rear wheels were so wide and those in the front narrower. He too had concerns about tipping having seen now two wrecked ships that tipped over in high winds. He knew that if this group had a number of technical questions about the project, Mr. Smellows talk after lunch would likely be a long one. He hoped that he would not be too late getting home tonight and missing too much of grandpa's birthday event. Danikel, Masela and their son Krikea lived in the family house near the old palisade wall area along with his Grandfather, Father, Mother and two siblings. He knew he would be asked many questions by the family as they all knew he was pleased and excited to have joined the new project.
After lunch Mr. Smellows presented several new drawings to further explain the critical working of the sail on turntable concepts. Danikel paid close attention so he could begin to understand the strange and wonderful workings of the Wind Waggon. The other team members likewise were attentive to gather more facts and understanding of the design concept so they could begin to detail the parts needed to build the Wind Waggon. Mr. Smellows asked the team to allow him to present each drawing without interruption after each of which he would answer questions.
The first drawing was a typical sail construction. Mr. Smellows design bore no resemblance to the sails used on ships. Each sail would consist of an internal wood framework to which the sail cloth would be fastened on one side only. The wood work would keep the sails of a uniform rectangular size. Each wood frame would have a bearing attached at both top and bottom so the sail could rotate freely all the way round. The bearing axis was about two fifths the way from the front of the sail resulting in a smaller forward portion than the back. Mr. Smellows pointed out that this was an essential part of the design and would be explained further in the next drawing presented.
A further feature was a metal impact plate at the bottom of the back section. The front portion opposite the impact plate was removed from the sail leaving a gap with the plane of the bearing. Mr. Smellows stated that the sail structure must be very light and very strong. The cloth sail would receive all the wind power while the wood framing would strive to keep the sail shape square and flat while transmitting the wind power to the bearings. The sail cloth was to be attached with rope or hooks so it could easily be replaced if damaged. Extra sail cloths would be carried during the trips. Further, the wood framing was to be held together with bolts so that a broken brace or part could be replaced from spare parts to be carried during the travels as well.
As would be expected questions flowed from the team when Mr. Smellows indicated that questions would now be responded to beginning with the more senior men and on downwards to the less. Ekelis the master wood worker raised his hand first and was recognized by Mr. Smellows. His questioning began, "Mr. Smellows, what forces must the sail withstand?" The response from Mr. Smellows was, "My estimate of forces is that the maximum for a sail will be about 3370 pounds in 60 mph winds equally divided between the two bearings."
Ekelis continued with, "The amount of structure seems small for such large forces based on our experience with waggon building. How much force will be applied to the Stop Block Strike Plate?" Mr. Smellows responded with, "The structure shown is notional only and we depend on the team to build sufficient strength into the structure keeping in mind the need to keep weight to the minimum as the sails will be rotating around on the turntable and we wouldn't want them to come loose or suffer damage due to rotating forces. The total force will be rather evenly distributed on the cloth of the sail and thence transmitted through the wood or metal structural components to the bearings. Regarding the strike plate, the rotational force of the sail is applied to the plate. That force is about 1/5th of the total sail force or about about 672 pounds."
Next Artia raised his hand with a question. After Mr Smellows pointed to him, Artia spoke, "The bearings must be metal to couple the forces mentioned to the turntable. How is the force of the upper bearing transferred to the turntable?" Mr Smellows indicated that a strong central shaft connected the upper bearing supports to the turntable.
Danikel raised his hand, was recognized and asked the following question. "Why are the bearings located nearer to the front edge of the sail?" Mr. Smellows replied to the effect that Danikel asked a very appropriate leading question which would be addressed in the next drawing to be discussed. He further asked that the team hold that question in mind as he began explanations of that fact.
Mr. Smellows then pointed to the next drawing where sail motion relative to the wind was presented for those sails moving towards the wind. Mr. Smellows stated that should a sail be misaligned somewhat with the wind, the imbalanced mounting would use the wind force on the sail to rotate it into alignment with the wind much like the feathers on an arrow, thus reducing sail forces to a minimum for those moving upwind. His explanation was sufficient to satisfy the team and hold any further questions. Mr. Smellows then presented the next drawing to address the forces on those sails moving with the wind.
"This next drawing is a bit more complicated but addresses the method used to extract significant rotational force from the wind applied to the turntable. That force will in turn be coupled from the turntable down through the shaft to the drive wheels below. Note that all of the sails moving towards the wind on the upwind side of the turntable sketch are aligned with their narrow edge to the wind. This reduces their rotational force nearly to zero. Notice also that the downwind moving sails CANNOT rotate into alignment with the wind due to the presence of the stop blocks. Those blocks keep the upper sails that are moving downwind rotated to the wind thus capturing much wind force and coupling the captured forces to the turntable. The upper sails have much the same arrangement with the wind as would water wheel paddles to the moving stream of water. Thus, those sails that capture wind power are held rotated as in a water wheel while the rest are free to rotate in alignment to the wind eliminating their rotational forces which would otherwise be counter to the upper sails."
Mr. Smellows continued, "this has been a long explanation, but it is the essential design feature of the turntable that extracts much force from the wind and further always aligns turntable capture operation to the wind regardless of wind direction without the need for operator intervention. I realize that this concept is rather complicated and will now entertain questions to develop a better understanding."
Neither of the senior personnel, Artia, Eklis or Adlier raised their hand, however, both Danikel and Penchist did so. Mr. Smellows recognized Penchist first who asked, "The sails at position four and five are reversed in position, why is that?" Mr. Smellows answered, "The sail at position four is rotating downward with the turntable, as soon as the angle is a bit more than shown the rear of the sail will come free of the stop block and rapidly rotate that sail into wind alignment reversing it's direction. As that sail continues rotating to position five it will now be in the alignment shown for position five in the diagram."
Danikel raised his hand and was recognized. "Since sails in position one and three are not aligned squarely with the wind, will their force be the same as for a sail in position two?" Mr. Smellows responded with. "Those two sails will have a force that is geometrically related to the angle they sustain with the wind in those positions. As a sail rotates from position zero through one, two three and four, it experiences a gradually increasing force that maximizes at position two then gradually reduces to zero at position four. The force increase and decrease are smooth and gradual suffering only from wind gusts. Thus at least three sails apply a total force of 2.7 times the force of the sail at position two."
At this point Ekelis raised his hand, was recognized and asked, "This means that the turntable turning force will be very large with about 5 tons of force applied at the sail bearing radius on the turntable. It appears that the turntable shaft would need to couple perhaps 45 tons of rotation force through the turntable shaft. Is that about right?" Mr. Smellows complimented Ekelis on his good math work and confirmed his estimations were about correct. Mr. Smellows now indicated that the turntable would be rotating at perhaps 3 to 5 times each minute, much faster that was possible with the draft animal driven turntable of the past.
Penchist then raised his hand, was recognized and asked, "That means that the turntable structure must transmit very high forces from the sail bearings to the turntable hub. What material will the turntable be made from?" Mr. Smellows responded that it was quite true that the turntable structure must transmit very high forces, both top and bottom structures coupling large forces to the shaft. He indicated he thought that suitable wood structures with metal attachment point gussets would work. He would later provide dimensional information for the turntable radius arms both top and bottom and suitable metal gussets to tie the parts to the bearings and central shaft. He further indicated that the central turntable shaft would likely be wood reinforced with metal hoops. Metal was too difficult as yet to work and obtain parts as large as the turntable shaft and radius arms. Angle alignment supports between turntable radius arms would possibly be metal rods which may be available to this project.
Adlier raised his hand, was recognized and asked, "The sails extend from time to time beyond the edge of the turntable, will they also extend beyond the sides of the waggon?" Mr Smellows replied that yes they would extend perhaps as much as two to three feet beyond the turntable and well beyond the waggon sides. This would not be a problem once the vehicle left the palisade gate. The gate to be used for exit of the vehicle would need to be modified in any event because of the height and width of the sail assembly.
Questions flew to Mr. Smellows from the various team members for several more hours. Eventually both the team members and Mr. Smellows were exhausted and a halt for the day was called. Danikel was very tired and glad that the meeting had not gone on too long after normal day end. The team drifted out the shop door and head for home knowing that the next several days would most likely be as tiring as the team struggled to learn the details of the wind waggon concept.
As Danikel walked out the door, his younger sister Jezala Groot and one of the other waggon team members, Frazitz Autmea we sitting on an outside waiting bench talking earnestly. Danikel was aware that the two had often met at the waiting bench and talked together while she waited for Danikel to come out. Danikel liked young Frazitz who had started working at Master Waggon Works two years past and was nearing the end of his Basic Apprentice period. Frazitz was obviously enamored of his sister and she seemed to take a strong liking to him. Danikel knew that soon Frazitz would come calling Danikel's father seeking to formalize their courting.
Danikel called for his sister to join him in his walk home so they both could be there for Grandfather's birthday celebration. She said goodbye to Frazitz and they separated letting their finger tips slowly part. Certainly love was in their future. Danikel teased Jezala as they walked home saying she would soon leave the Groot family if she wasn't careful with young Frazitz. Jezala frowned and lightly punched Danikel's arm then smiled thinking about the possibility of being Frazitz' mate. She was about of age and happy with the thought that such a joining might actually come soon. The two were both contented as they walked home. She knew that Frazitz was soon going to ask permission to court.
No comments:
Post a Comment