|
|
Wolfgang,
I am surprised that you remain unconvinced. Chris' analysis on this topic has been the most thorough and careful analysis I've encountered. He doesn't just look at the outside symptoms of the problem, but also delves into aspects of the pump and its design (the number of different configurations and variations available) that I never even considered previously.
I thought it was just a pump, I had no idea that the inner workings had such an impact on how the system operated until he took the time to take me through it all.
I have had the opportunity to work directly with Chris in a professional setting, I have not encountered a more keen understanding of how things work and what questions to ask when things go wrong than that of Mr. Zavatson. He has been able to point out errors in my thinking and how I look at problems in a way that has been very beneficial to me.
These remarks that you have directed to him concern me greatly. You aren't asking any questions, you aren't having a discussion, you aren't trying to reconcile the deficit of your understanding of these things, you are attacking him personally. That's where you are losing me.
I'm starting to believe that the results of someone following your advice and using your system could have dangerous if not life threatening consequences.
I think what I would like to see from you is a bit more effort to reconcile your the observations Chris has replicated numerous times on the bench and in the air. This is what I'm used to seeing when good willed scientists and engineers disagree.
I have observed Chris quickly change course if evidence is presented that refutes his conclusions. He is not concerned with being right, he is concerned with what is right, constantly rechecking and questioning his own results.. I think you are a very smart and capable individual and we would all benefit if you adopted these same principles.
Thank you,
Kevin Stallard
N969RJ 150 hrs and counting!
________________________________________
From: Lancair Mailing List [lml@lancaironline.net] On Behalf Of Wolfgang [Wolfgang@MiCom.net]
Sent: Monday, April 28, 2014 5:59 AM
To: lml@lancaironline.net
Subject: [LML] Re: Gear Down...INOP
Chris,
I remain unconvinced with your theory. You have suggested that the pump will somehow shut down immediately after it has started up due to some pressure pulse. The mechanisim of which you have yet to clarify, let alone demonstrated.
I'm tired of your kibitzing and since you have proven that you can't let it go, I will and leave you to humor yourself.
Wolfgang
----- Original Message -----
From: Chris Zavatson<mailto:chris_zavatson@yahoo.com>
To: lml@lancaironline.net<mailto:lml@lancaironline.net>
Sent: Saturday, April 26, 2014 1:28 PM
Subject: Gear Down...INOP
Wolfgang,
<<“I believe in redundancy and it looks like you don't….”>>
I am a big proponent of redundancy. That is redundancy defined as a true back-up to an otherwise trouble-free system.
First, I have redundant switches to power the pump solenoids. This allows me to raise and lower the gear in case of the failure of either of the pressure switches. It doesn’t happen very often, but it does happen - twice in 17 years of flying my 360.
I also have redundant gear down indications. Two completely separate systems, separate switches, separate wires and separate indicators. The second set of switches is mounted directly on the over-center links.
I even carry two iPads and a iPhone - just in case
<<“The pressure pulse you're talking about will subside (glad you agree) and as it does, because the cylinder is only partially extended, the cylinder will continues to extend, the low switch will close again, and enable the pump to continue . .”>>
The part you seem to be missing here is that the momentary pulse is not directly turning off the pump. Thus when the pulse subsides, the pump doesn’t just spring back to life. The pulse pushes the spool in the wrong direction -against the pump flow. This locks the poppet that the pump just opened up a fraction of a second earlier. When this happens, the high side begins to pressurize along with the low side. As soon as both sides reach the low side pressure setting, the pump is turned off. This is why you see both high and low circuits pressurized to the same value in Lorn’s photo.
To prevent this, the low side pressure settings should be raised. 800 psi has proven sufficient. The high volume gear pump will reduce the size of the pulse since the higher volume pump is able to absorb incoming fluid at a higher rate.
I highly recommend pressure gauges for both high and low circuit be installed in a location visible to the pilot. The state of the system can always be verified. One can immediately diagnose any in-flight problem. Leaks can be caught early. And adjusting pressure settings is no longer guess work.
Chris Zavatson
N91CZ
360std
www.N91CZ.net
|
|