The reduction in tlie density of roads with the balloon system leaves the land man- 

 ager with limited access to manage the land. This can be a problem especially where 

 fire, disease, or insects are a threat because proper slash treatment is difficult due 

 to poor access. This is not to say that proper slash treatment cannot be accomplished, 

 but that the high costs of treatment must be considered as an extra cost in the balloon 

 system as compared to logging systems using a more dense road network. Regeneration 

 and other management functions also will be more difficult and expensive because of the 

 limited access provided by tlie balloon logging road system. 



PHYSICAL CHARACTERISTICS 

 AND LOGGING CAPABILITIES 



This sale proved the physical feasibility of logging with a balloon system in the 

 Idaho Batholith area; however, the conditions are not ideal. Steep slopes, generally 

 45 to 90 percent, made working conditions difficult for the riggers, fellers, and 

 choker setters. The highly dissected drainages made frequent cable road and layout 

 changes necessary in order to reacli the logs. Figure 8 shows the severity of the 

 terrain on a contour map of the logged area. 



Tlie main piece of equipment for the ha 1 f -mi 1 1 ion-dol lar (1971 cost) yarding system 

 was an onion-shaped, Dacron-neoprenc fabric balloon which is 113 ft (34.4 m) in height 

 and 105 ft (52 mj in diameter. The 560,000 f t ^ (15,857 m^) helium-filled balloon had 

 a net lift of 22,500 lb (10,205 kg) shortly after inflation. This lift varies consid- 

 erably witli elevation and temperature. (Temperatures in the Harden Valley area of Idaho 

 range from below zero (-17.8° C) to above 100° F (37.8° C)). On cold mornings when the 

 temperature was below freezing, decreased lifting capacity slowed the yarding operation 

 considerably. The lifting capacity of the balloon is also greatly reduced by even a 

 thin covering of snow or ice. A lieavy snow can cause the balloon to tear due to the 

 snow load or from the rebound wlien a snow load slides from the balloon. A tear did 

 result from a sliding snow load and the resulting quick load release. The snow condi- 

 tions at the logging site required that the balloon be stored for 3 or 4 months during 

 each winter. Storage is a problem, as there is no economical way to deflate the 

 balloon and store the gas. Snow removal was a continual maintenance burden for the 

 logging company during winter bedding of the balloon (fig. 9), but it was the most 

 economical solution since enough helium to fill the balloon cost approximately S25,000. 



A very small amount of leakage occurred during normal operations, but this was not 

 a problem and was within the expected loss estimates. The balloon's reflective aluminum 

 surface was repainted during the 3-year sale in order to prevent excessive weatliering of 

 the fabric and to control temjieratures caused by radiation from the sun. 



Wind affects yarding in pro])ortion to vcloci.ty, with the ojieration being consider- 

 ably slower as the limiting operable velocity of approximately 25 mi/li (40 km/li) is 

 approached. \'ariable winds are also troublesome even at low wind velocities due to the 

 problems with landing loads and positioning over the logs for hooking cliokers. 



6 



