An aside: Other uses of the chair drawing
A side ramble as Adam Buxton might say … being able to draw the chair conformation of cyclohexane is really useful. It is useful when looking at six-membered rings like glucose. It is useful when predicting the stereochemical outcome of many reactions like the aldol or sigmatropic rearrangements. It is also useful when trying to draw other sizes of rings.
The following drawings are not always the favored conformation but they are frequently close (so are likely to be conformers). To draw the butterfly conformation of cyclobutane, take one corner of your chair drawing and add a bond to make a four-membered ring. Then delete the other atoms. Here, I’ve kept most of the C–H bonds in the same position as before but tidied two up to give a better sense of perspective.
Drawing cyclobutane from a six-membered ring.
A similar process will give you the envelop conformation of cyclopentane. Again, simply keep one corner and then cut the off. This very close to the favored conformation and needs no tidying up.
Drawing cyclopentane from a six-membered ring.
Larger rings are slightly more challenging. It is hard to determine their favored conformation. Just adding an extra carbon gives cycloheptane in a chair-like conformation. This is probably a conformer but it is not the most stable conformation of the ring due to the axial-like hydrogens (in orange) interacting. Slight rotation of the newly draw bond gives the twist chair which is thought to be the most stable conformation. Similar processes can give the larger cycloalkanes.
Drawing cycloheptane.