SUMMARY / RELATED TOPICS

Turbopump

A turbopump is a propellant pump with two main components: a rotodynamic pump and a driving gas turbine both mounted on the same shaft, or sometimes geared together. The purpose of a turbopump is to produce a high-pressure fluid for feeding a combustion chamber or other use. There are two types of turbopumps: a centrifugal pump, where the pumping is done by throwing fluid outward at high speed, or an axial-flow pump, where alternating rotating and static blades progressively raise the pressure of a fluid. Axial-flow pumps have small diameters but give modest pressure increases. Although multiple compression stages are needed, axial flow pumps work well with low-density fluids. Centrifugal pumps are far more powerful for high-density fluids but require large diameters for low-density fluids. Turbopumps operate in much the same way as turbocharger units for vehicles: higher fuel pressures allow fuel to be supplied to higher-pressure combustion chambers for higher-performance engines. High-pressure pumps for larger missiles had been discussed by rocket pioneers such as Hermann Oberth.

In mid-1935 Wernher von Braun initiated a fuel pump project at the southwest German firm Klein, Schanzlin & Becker, experienced in building large fire-fighting pumps. The V-2 rocket design used hydrogen peroxide decomposed through a Walter steam generator to power the uncontrolled turbopump produced at the Heinkel plant at Jenbach, so V-2 turbopumps and combustion chamber were tested and matched to prevent the pump from overpressurizing the chamber; the first engine fired in September, on August 16, 1942, a trial rocket stopped in mid-air and crashed due to a failure in the turbopump. The first successful V-2 launch was on October 3, 1942; the principal engineer for turbopump development at Aerojet was George Bosco. During the second half of 1947, Bosco and his group learned about the pump work of others and made preliminary design studies. Aerojet representatives visited Ohio State University where Florant was working on hydrogen pumps, consulted Dietrich Singelmann, a German pump expert at Wright Field.

Bosco subsequently used Singelmann's data in designing Aerojet's first hydrogen pump. By mid-1948, Aerojet had selected centrifugal pumps for liquid oxygen, they obtained some German radial-vane pumps from the Navy and tested them during the second half of the year. By the end of 1948, Aerojet had designed and tested a liquid hydrogen pump, it used ball bearings that were run clean and dry, because the low temperature made conventional lubrication impractical. The pump was first operated at low speeds to allow its parts to cool down to operating temperature; when temperature gauges showed that liquid hydrogen had reached the pump, an attempt was made to accelerate from 5000 to 35 000 revolutions per minute. The pump failed and examination of the pieces pointed to a failure of the bearing, as well as the impeller. After some testing, super-precision bearings, lubricated by oil, atomized and directed by a stream of gaseous nitrogen, were used. On the next run, the bearings worked satisfactorily but the stresses were too great for the brazed impeller and it flew apart.

A new one was made by milling from a solid block of aluminum. The next two runs with the new pump were a great disappointment; the problem was traced to the exit diffuser of the pump, too small and insufficiently cooled during the cool-down cycle so that it limited the flow. This was corrected by adding vent holes in the pump housing. With this fix, two additional runs were made in March 1949 and both were successful. Flow rate and pressure were found to be in approximate agreement with theoretical predictions; the maximum pressure was 26 atmospheres and the flow was 0.25 kilogram per second. The Space Shuttle Main Engine's turbopumps spun at over 30,000 rpm, delivering 150 lb of liquid hydrogen and 896 lb of liquid oxygen to the engine per second. Most turbopumps are centrifugal - the fluid enters the pump near the axis and the rotor accelerates the fluid to high speed; the fluid passes through a diffuser, a progressively enlarging pipe, which permits recovery of the dynamic pressure. The diffuser turns the high kinetic energy into high pressures, if the outlet backpressure is not too high, high flow rates can be achieved.

Axial turbopumps exist. In this case the axle has propellers attached to the shaft, the fluid is forced by these parallel with the main axis of the pump. Axial pumps tend to give much lower pressures than centrifugal pumps, a few bars is not uncommon, they are, still useful – axial pumps are used as "inducers" for centrifugal pumps, which raise the inlet pressure of the centrifugal pump enough to prevent excessive cavitation from occurring therein. Turbopumps have a reputation for being hard to design to get optimal performance. Whereas a well engineered and debugged pump can manage 70–90% efficiency, figures less than half that are not uncommon. Low efficiency may be acceptable in some applications. Turbopumps in rockets are important and problematic enough that launch vehicles using one have been caustically described as a "turbopump with a rocket attached"–up to 55% of the total cost has been ascribed to this area. Common problems include: excessive flow from the high-pressure rim back to the low-pressure inlet along the gap between the casing of the pump and the rotor, excessive recirculation of the fluid at inlet, excessive vortexing of the fluid as it leaves the casi

Walther von Bonstetten

Walther von Bonstetten was among the founders and most important members of the Swiss Boy Scout association Schweizer Pfadfinderbund, was elected President in 1918 and kept a leading role until 1942. He studied law and became attached to the Swiss embassy in Berlin and in London, it is there that he came into contact with the Scout movement in its beginnings and with Baden-Powell. On his return to Switzerland he founded the first group in Geneva. In 1913, he was among the founders of the Pfadicorps Patria in Bern, one of the early Swiss Scout units. From 1918 to 1927, he served as President of the Swiss Boy Scouts, he founded the "Scouts International Home" Association in 1923 to be known as Kandersteg International Scout Centre. He served as Chief Scout of Switzerland from 1927 to 1934. In 1928, he received the Silver Buffalo Award from the National Court of Honor of the Boy Scouts of America for remarkable and extraordinary achievements for the youth. From 1934 to 1942 he served as President of the Swiss Boy Scouts.

He was awarded the Bronze Wolf, the only distinction of the World Organization of the Scout Movement, awarded by the World Scout Committee for exceptional services to world Scouting, in 1937. He became President d´Honneur of the Scouts Alpine Club in 1946. Von Bonstetten served on the International Scout Committee of the World Organization of the Scout Movement from 1927 until 1947, he served one year as Honorary Vice-President of the International Committee until his death in 1949. Dominik Stroppel:Kurzportraits der wichtigsten Pfadfinderführer 1918 - 1945 -Walther von Bonstetten Photo et biographie de Walter von Bonstetten

Baron von Redberry

Baron Von Redberry was a cereal created by General Mills around 1972 that featured a World War I era German pilot modeled on “Red Baron” Manfred Albrecht Freiherr von Richthofen. The cereal itself consisted of berry-flavored oat cereal with sweet berry marshmallows and tasted of fruit punch. Baron Von Redberry was the nemesis of mascot of another General Mills cereal brand. In the vein of the cereal rivalries Quisp & Quake and Count Chocula & Franken Berry bickering over which one was better, Redberry would proclaim, "Baron Von Redberry is der berry goodest!" and Grapefellow would counter, "Sir Grapefellow is the grapest!" Sir Grapefellow Mansour, David. From Abba to Zoom: A Pop Culture Encyclopedia of the Late 20th Century. Andrews McMeel Publishing. P. 25. ISBN 9780740793073. Week, Advertising. "8 Great General Mills Cereal Heroes That Deserve a Reboot". Huffington Post. Retrieved 2018-07-10. "Sir Grapefellow and Baron Von Redberry". Www.food.pop-cult.com. Retrieved 2018-07-10. Faucher, Jessica. "5 of our forgotten mascots".

A Taste of General Mills. Retrieved 2018-07-10. Photo of Baron Von Redberry box