Question about motor lenght on indoor high performance models

From: Manuel Cisneros <macs8953_at_yahoo.com>
Date: Tue, 22 Aug 2017 07:22:28 +0000 (UTC)

Forgive my ignorance on the subject, but is there a general rule about how long a motor should typically be used on high performance indoor models (F1D, F1L, F1M) in relation to the prop hook to rear hook distance?

I know these classes are different WRT to motor weight specification - F1D and F1M specify maximum motor weight, F1L doesn't - so I would expect the selection of a relative motor length would be different for different classes, but I am trying to understand the adage that seems to implore flyers to adjust motor dimensions based on how many turns are left in a motor at touchdown to optimize flight time based on available motor energy for different cross-section/length combinations.

One reason I ask is that in perusing some (admittedly older) designs, I've found motor lengths to be specified anywhere from 80-90% of the hook-to-hook distance to as long as 120%-130%.
TIA.
Manuel.
Received on Tue Aug 22 2017 - 07:22:33 CEST