Talk:Bi-elliptic transfer

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[edit] Incorrect numbers

The introduction to the article contains the following quote: "the bi-elliptic transfer may require a lower amount of total delta-v than a Hohmann transfer in situations where the ratio of final to the initial semi-major axis is greater than 15.58." This implies that the Hohmann transfer requires a lower delta-v than the bi-elliptic transfer at a final to initial semi-major axis ratio of lower than 15.58. This is shown to be incorrect later in the article. The example given at the end uses a ratio of 14:1 (93800:6700) and shows that the bi-elliptic transfer requires a lower delta-v. Either the 15.58 is wrong (or misleading) or the example is wrong, and I don't know which. Also worth noting, the Hohmann transfer article indicates that the bi-elliptic transfer may require less delta-v for ratios exceeding 12. One of the two articles, or both, probably need to be edited to correct this error/discrepancy.

137.240.136.81 22:04, 11 September 2007 (UTC)

There was a discussion in the forum for a flight simulator called Orbiter on the subject of bi-elliptic transfers. I tried searching today but there is an error at the moment so I can't post the specific thread but here is the forum where it resides [1]. During the discussion someone mentioned this discrepancy in the article here. They attributed the difference to stemming from different ways of computing it, or a difference in assumptions, or something of that nature. So both numbers are "correct" in some sense they are just the results based on different methods. I am not sure what the methods, etc were so I cannot contribute that but I thought I would throw my 2 cents in none the less. -AndrewBuck 01:20, 22 September 2007 (UTC)

The intial diagram doesn't seem to make much intuitive sense. It actually looks as though more delta v would be needed to make such a small change to a circular orbit using the bi-elliptic transfer illustrated, compared to the Hohmann transfer. Sketching out the later example to scale looks much more sensible, (if perhaps a little unwieldy). Nonetheless, would it be worth making the diagram match the later example's figures? —Preceding unsigned comment added by 84.69.96.243 (talk) 01:42, 23 February 2008 (UTC)