On 6/6/2018 9:06 PM, Henry Spencer wrote:
On Wed, 6 Jun 2018, Henry Vanderbilt wrote:
... Not having to do single-tube roll control opens up the control options considerably, especially if you don't have to do both pitch and yaw in a single-tube configuration either (which permits, e.g., differential throttling or single-axis gimbals).
I'd be inclined against differential throttling for an OTRAG-type vehicle. My impression is that valves get expensive, heavy, and/or unreliable the instant you ask for anything beyond simple shut-to-open from them. (And sometimes even than.)
Proportional control does complicate valves, for sure. For fine control, best results typically involve a throttling valve that *doesn't* also do on/off control, although then of course you've got twice as many valves.
If you do want a single combined valve, the added overhead can be reduced by having, not full proportional control, but a three-way choice: closed, full open, and half open. If memory serves, that was what OTRAG did.
