Roy Page wrote:
: Well you could be correct about a possible vapor lock.
: As far as I can see the fuel lines are not insulated.
: The autofuel STC on an Archer calls for mods to the fuel system to prevent
: vapor locks.
: But I do run on 100LL which is less volatile that Regular Gas.
: But if the PA28 aircraft are prone to vapor locks, I would have expected to
: see an AD a long time ago ?

: Thanks for the input.

My cherokee could be vapor lock, but I've seen it on three different cherokees
that I've flown, with autofuel or on 100LL.

The flow of the pump is just barely adequate. Petersen described the "ditch
test" where they had to put the tail of the plane down in a "ditch" to get a high
nose-up attitude. In the worst conditions, the stock fuel system was unable to
deliver the flow rate with an acceptable safety margin. Thus the modifications to the
fuel system for autofuel STC.

What *really* bugs me is that a PA28-160 has to do the fuel mod for the STC,
but if it's got low-compression pistons (i.e. PA28-140/150), the fuel mod isn't
required. You tell me how changing the pistons (i.e. low compression vs. high
compression) changes fuel flow. Safety through liability and regulation...

-Cory


************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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