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Yes, I'm routinely accused of
insanity. Thus, the request for the insanity check. Judging by your
response I must proceed.
>> Yes, the 40 liter
one looks perfect. You must let us know how it works(especially if you use
it to move the CG forward). Of course, you must tell us which side (up or
down) you choose to place it on...............
I am looking at the .16 Liter accum.
It will go on an up side HP line. (sorry, I thought it was self evident which
chirp about which I was speaking- I have no downside chirp). And yes,
it'll go as far forward as I can bury it. I've got a Catto blade enroute
and I'll be disappointed if the aft CG shift cancels out any improvement in
efficiency over the Hartzell.
>>> Page 6 of the
accumulator pdf outlines failure modes for which such devices are useful - our
simple system doesn't fit any of them as the dump valve, gravity and a few
springs solve the most serious problem - failure to extend and lock.
Page 2 has the following quote:
" maintain system
pressure
by compensating for
pressure loss due to
leakage "
Internal leakage compensation is the part
that I was concentrating on. The downside issues will all work the
same. The shuttle valve and dump valve still relieve upside pressure
(albeit a little longer). Gravity will generally repeat its usual
performance.
>>>> I
disagree with the way you have characterized air as both a good and bad
component of "system leak". However, leaks there may be. You could
test your theory by introducing air, hither and yon, by cracking a few fittings
and letting some (or a lot) into actuators. Then, see if the system appears
"sealed."
Air is good if your breathing and bad if
leaking into your brain. OK, I'll go out and rebuild one this am and
report back. Oh, but wait, I guess the rebuild of the leaker will have an
affect on our test.
>>> Internally
the system relies on 6 piston o-rings and at least three more in the pump,
not to mention the actual operational position of the shuttle valve
and the dump valve (it is not worth talking about leaks to the outside - shaft
and actuator end seals - they must be fixed immediately). The most common
cause of internal leaks are scratches on the surfaces where the o-rings
must seal or o-ring failures. These are frequently precipitated by
dirt in the system, sometimes present because of building techniques,
assembly faults as the crucial o-rings have to pass some ugly cuts (ports) in
the cylinders during assembly and cylinder scratches also introduced by
assembly. Also, not all the fluid leaves the actuator as there is space at
either end and a rebuild will frequently find o-ring residue (darkening the
fluid) in each end at disassembly. Some leaks only occur (show up) at the
end of a stroke, but not on both sides of the system.
How does this help stop the chirps? My
point remains. You can make them all new and still get a smidgen of leak
through that is detrimental to the system (chirp, chirp, chirp).
>>> Right now I
have a 20-second cycle blip on the down side and none apparently on the up side
- it has been that way for 18 months. I, too, have grown weary of
replacing/rebuilding actuators, etc. I see red when I think of the
system. It will have to break a lot worse than it is now for me to start
debugging.
I use a sheet of painters plastic and a
bottle of Simple Green. I see green when I work on Hyds. You're an
electrics guy. Does that little chirp every 20 seconds not bother you just
a little? You know, arcing and corrosion in the relays, airborne fire,
alternator shorting, etc?
>>>>>> If you have
actual serious leaks, the accumulator will not help. If your air concept
is correct and internal system leak occurs, you would need a very large
reservoir as the accumulator slowly pushes fluid to the other side. You
cannot use two accumulators because the pressure requirement is different on
each side and if passage of the fluid built up too much pressure on the other
side, the pressure switch would not allow the pump to operate. So
there.
Which is it? You disagree with
agreeing with me? Or agree that air concept is correct? Yes, a
serious leak would still require repair. However, my premise is to
mitigate the slow (not serious) leak.
>> PS: Weld the gear
down and use wheel pants. See Mr. Hammer.
Notice that Steve is now
slower. Bruce still had me by 3 mph in the Memphis 100. New prop
should crush him, too. See sportairrace.org for latest league standings
(I'm doing OK!).
Larry Henney
Doesn't Like Pump Chirps
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