Speed Scale Chart

Scale	miles/hour	km/hour
-6	4	6
-5	5	8
-4	6	10
-3	7	11
-2	8	13
-1	10	16
0	12	19
+1	14	23
+2	17	27
+3	20	32
+4	24	39
+5	30	48
+6	36	58
+7	43	69
+8	52	84
+9	62	100
+10	74	119
+11	89	143
+12	107	172
+13	128	206
+14	154	248
+15	185	296
+16	222	357
+17	266	428
+18	319	513
+19	383	616
+20	460	740
+21	552	888
+22	662	1065
+23	795	1279
+24	954	1535
+25	1145	1843
+26	1374	2211
+27	1648	2652
+28	1978	3183
+29	2374	3820
+30	2849	4585
+31	3418	5501
+32	4102	6601
+33	4922	7929
+34	5906	9505
+35	7088	11407
+36	8506	13689

Posted by Gordon A. Cooper in 2007.