Beech-Archive.digest.vol-ae March 19, 2001 - September 10, 2001 Sent: Monday, March 19, 2001 5:27 PM Subject: Re: Vacuum Relief Valve > > Al, > > Oh! Tactair was a new (1955) concept in autopilot design in that > it used air gauges for both sensing and operation of the controls. Weighing > less than ten pounds, the pneumatic system used no electric motors or vacuum > tubes, nor a demand of any kind on the electrical system. The autopilot is > ready to go as soon as the engine is running -- no warmup time required.
> It'll hold a heading to 1 degree and an altitude to 20 feet. Price back in > the late 50's was about $2,500.00, installed. > > The only demand it put on the plane was an increased appetite for instrument > vacuum air. You had to crank up the vacuum from 4-1/2' to 8-1/2' at the > vacuum regulator, and a second Tactair regulator split off 4-1/2' for the > instruments and 8-1/2' to drive the bellows-style servos to tug on the > appropriate control cable. Rather idiot-proof, if you ask me. I like mine -- > a lot. > > Are you dumping the Tactair to upgrade a Lear L-2 autpilot?:-) Installed > weight of the L-2 is only some 18-34 lbs, and it will track VORs and a > glideslope.
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Takes some 10 amps of juice to power those vacuum tubes, though. > > Well, give Bim Babis a call. He has some Tactair parts (tho' not all) for the > vacuum regulator. He has a different spring for the regulator to give it a > bit more oomph.
If yours has such a spring, you need to trade it back in for > the ordinary kind. > > Tim Babis ('Mr. Tactair') > Tactair Autopilots > Hangar 3, Lunken Airport > Cincinnati, OH 45226 > 513-871-8569 > tsbabis(at)goodnews.net > > Tim's website is: > > > Ron Davis > > > A J DeMarzo wrote: > > > > > > Thanks Ron; > > Always detailed instructions as only you know how to pen. Good thing your > > company makes gadgets that the common man uses. Where else would you get > > all that instructional experience? I'll call your boss in the morning and > > see if I can get you a good raise! > > > > You're right, the valve is probably the simplest thing on the airplane > >Torrent video copilot element 3d all 7 packs crack machine. (other than the owner/pilot).
I've performed all of the backbreaking work > > you've described and that's how I got it down to 8 lbs. The action > > is nice and smooth as the unit is sparkling clean, in and out. Possibly > > along the line, someone replaced the spring with a wrong one as I can't get > > it any lower than 8. The reason this was never detected is because maximum > > vacuum was allowed past this valve going to the 'sub' valve of the Tactair! > > Yup, even uninstalled, the damn thing is troublesome!
Thanks for the > > effort. > > AL > > > > ----- Original Message ----- > > From: 'Ron Davis' > > To: > > Sent: Monday, March 19, 2001 3:43 PM > > Subject: Re: Beech-List: Vacuum Relief Valve > > > > > > > > Al, > > > > > > Aw, c'mon. The vacuum relief valve has gotta be one of the simplest gizmos on > > > the Bonanza. > > > > > > Inlet air from the gyros on one side, outlet suction to the vacuum pump on the > > > other, a relief inlet opening on the bottom, and the relief spring setscrew > > > on the top.
> > > > > > As the suction increases (from the vacuum pump), it overpowers the spring that > > > closes the relief opening. Additional air enters the regulator until t he > > > vacuum pressure and the spring pressure equalize.
> > > > > > Want more vacuum? Screw the spring setscrew down, and increase pressure on > > > the relief valve so it stays closed longer. Back it off a bit. > > > Once set, you shouldn't have to mess with it until you add or remove a > > >Nissan consult ii software. vacuum-powered instrument, or change the vacuum pump. > > > > > > Since you replaced the relief valve and your problem went away, we can > > > conclude that the valve was indeed the cause of your problem. Usually, you > > > don't need a rebuild kit for these things -- just a good cleaning. There is > > > usually a screen on the bottom of the relief valve to keep the larger debris > > > from getting sucked in.
Its weave is comparable to a screen door. Air goes > > > past the screen, through a pipe, and out the top of the pipe into the center > > > cavity of the relief valve. The top of the pipe will have a plate on it which > > > is held down by a spring. The plate rides up, letting some relief air in, and > > > the spring pushes down on it to only the -right- amount gets in. > > > > > > It sounds like your valve is gummed up. Gummy oil and soot, over years of > > > operation, will clog the plate so it doesn't move freely, and may stick > > > closed.
The cure is a good cleaning in solvent. > > > > > > You could probably just dunk the entire regulator into a tank of solvent and > > > in a couple of days it ought to be as good as new. I suppose that the intake > > > screen could be totally clogged, too, but this method will cure both problems. > > > > > > Or, you could be a glutton for punishment, and disassemble it, and clean each > > > part separately. This isn't brain surgery. The hardest part will be removing > > > it from the other vacuum lines without tearing the hoses, and you've already > > > done that. > > > > > > I know I've got a photo or two lying around of a disassembled relief valve.