Drew and Walter,
Thanks for the input. You're cautions against adding complexity and weight
are noted, and I am only looking at this as a far-out possibility. As a
theoretical thing, it's still an interesting idea to me.
Wouldn't it be possible to just add another hydraulic "circuit" coming out
of the pump? The flap selector would need to have a neutral position that
would allow pressure to return to the reservoir while locking pressure in
both sides of the flap actuator. This way you could run the the gear without
moving the flaps. When running the flaps, pressure would also go to the
gear, but would only act to hold the gear in the selected position.
Alternatively, you could use a gear selector with a neutral position as
well.The Piper Navajo has a gear selector that returns to neutral
automatically when hydraulic pressure reaches a certain value after gear
extension or retraction, allowing fluid to circulate continuously in the
system. That system uses two engine driven pumps that obviously run whenever
the engines do, which is most of the time in my experience.
With a two way actuator wouldn't it be simple to get reflex? If you have the
pump mounted between the seats, wouldn't it be a pretty easy plumbing job to
route lines over to the left side to an actuator attached to the mixer arm
in the same location the teleflex would? If you wanted the selector on the
instrument panel, that would be more lines of course, but it seems like
there wouldn't be much of a net weight change. An actuator, lines and
selector, a bit more fluid. You would shed the teleflex, flap handle, and
reinforcements to the roof.
A position indicator would be an integral part of the system because the
flap angle would be infinitely adjustable and would not have any "notches".
You could make a simple indicator on the instrument panel using a small
diameter flexible pushrod (a model airplane pushrod would work) from the
mixer arm to the indicator.
Oh well, that's the kind of thing I think about to keep myself awake when
driving to work at 4:00 am.
Jesse
From: WALTER KLATT <
Walter.Klatt@shaw.ca>
Reply-To: <
rebel-builders@dcsol.com>
To:
rebel-builders@dcsol.com
Subject: Re: Hydraulic flaps
Date: Mon, 06 Feb 2006 15:53:49 -0800
While many have complained about the slack in the stock system, this is not
an item that I would change if I was building again. First, the only time I
really needed full flap on my Rebel was for amphib take-offs both on water
and land, and the stock system did the job just fine. Landings are just
half flap. The stock system also works well with reflex. The only nice
change would be the dog leg handle, but I don't even have that on mine. On
wheels, you seldom need full flap, but they do really work if you want to
drag it in with a little power to a short field. Should be no problem in
coming to a stop in 400 feet or so, if you really want to. Take-offs on
land for me were always faster than landing, so that was never an issue
(with an 0320).
Remember, too, that these things all add weight, cost, and time, so you
need to pick and choose which mods are really necessary. Unless you like
building more than flying...
JMHO
Walter
----- Original Message -----
From: Drew Dalgleish <
drewjan@cabletv.on.ca>
Date: Monday, February 6, 2006 12:46 pm
Subject: Re: Hydraulic flaps
I think it would be a plumbing nightmare to install all the
selectors you'd
need to use the same pump for both flaperons and landing gear.
I've given
some thought to using a simple hydraulic system with a master
cylinder on
the roof and a slave moving the mixer up and down. This would
solve the
problem of slop in the teleflex cable but I don't think it would
work to
reflex the flaps. So you could add a big spring to lift the flaps
but then
it might take too much effort to lower them. So my personal
solution is as
usual to do nothing The teleflex cable works sort of OK and if I
want to
come down right now a full forward slip can get me a descent of
over 2000fpm.
At 03:39 PM 2/5/2006 -0800, you wrote:
Has anyone considered using the hand operated hydraulic pump for
amphib gear
to power a hydraulic actuator for the flaps as well? You could
pump the
flaps up and down like a Beaver. Sorry, I must be on a Beaver
kick or
Drew
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