cliffy Posted December 15, 2020 Report Share Posted December 15, 2020 (edited) The biggest issue with Brittian alt hold is the trim eyeball There are 2 types IIRC one plastic and one brass The brass one is the good one IIRC BUT it MUST line up in the center of the eyeball when unpowered. That is the crux as these are not available any more. Finding a good for replacement is like finding gold in the parking lot. Edited December 15, 2020 by cliffy spelling Quote Link to comment Share on other sites More sharing options...
Nukemzzz Posted February 22, 2021 Report Share Posted February 22, 2021 On 6/10/2018 at 7:36 AM, Evan Amaya said: Yesterday my wife and I flew from, South Carolina to East Texas. Did it in 4.5 hours with a 7kt head. I turned on the autopilot at 500ft agl , flipped to gpss and never touched the yoke the entire trip except for landing/takeoff. Very happy with the results. ATC had me go off course twice for traffic and I ed the G5 to heading mode then when advised to turn back on course went back to gpss and the plane smoothly went back to my original course. Right now I have the scale factor set at 2. I may play with this some more but in route I can’t complain. This caught my attention because I'm looking to add GPS to my M20E and the Brittain system almost works (Tracks but wonders back and forth quite a bit on VOR). You used the G5's to control altitude as well? This is what has me confused the most. My system has the hidden gyro near the firewall and not the TC. I have altitude and pitch hold. I'm not sure if they work. Pitch kinda worked, now it isn't... probably can be fixed. Altitude.. don't know yet. Long story. lol Planning to add 355 and G5's. I don't know how to get Brittain to follow the GPS. Assuming you found a legal certified path, how about if I take my plane to SC and you do what you did to yours to mine? lol Where I'm headed is below. This is what I'm sending out to get quotes with. I'd add the G5 AI like you for sure if it allows me to have GPSS and altitude control with the Brittain. Quote Link to comment Share on other sites More sharing options...
TCUDustoff Posted April 26, 2021 Report Share Posted April 26, 2021 So this goes back a few pages to when folks were talking about driving a AccuTrack with an Arduino, but I'm curious if I am reading this correctly and hope some of you EE guys and gals can help me.... (Bear with me here as I'm probably going to end up all over the place) The previous owner had a Terra TN200D hooked into NAV2; not sure how they did this, as the output for that unit is a single wire VOR signal with a common wire not L+/R+. I think this is called a composite output? Anyways, it did appear to work in the NAV2 input. When I removed all the old stuff, unfortunately, many of the solder joints failed so those wires came out of the dsub and I'm not sure how they connected it. *Uuugghhh* Anyways, I am also putting in G5s. Looking at the manual, the GAD29b seems to want to output a ROLL ERROR Hi and a ROLL ERROR Low (Guessing signal and reference ground?). Now I'm an ME guy by schooling, not EE, but the below 1st input stage of the B-11 circuit diagram looks like a non-inverting differential Op-Amp. Also looking at the ARINC standard for CDI deflection, it APPEARS as if full scale deflections is a 150mv delta between the L+/R+ wires. If I read this circuit correctly, it MIGHT be possible to input either the composite output of the TN200D or the one of the ROLL Error Pins into the L+/R+ pin and have this work. The Brittain system appears to work by pushing +10V or -10V to the control valve, so all this OpAmp should be looking for is a delta. Compared to ground, we WILL get that in this config. I might have to flop the wires around (change input from R+ to L+, for example), but I think its possible. As far as the TN200D goes, this assumes max magnitude of the output signal is something the B-11 can take. With the G5, at least, it appears you can adjust the voltage for full deflection so that shouldn't be an issue. Worst case scenario (from a course tracking standpoint) is the gains would be wonky and it would react too fast or too slow....or it would only turn one direction Anyways, a lot of guessing here and scratching my head while reviewing my old EE books. I can always throw in some wires and then try to do some testing with my o-scope while at the VOR test point on the field, but I thought I'd see what you guys think. P.S. If the photos don't appear, let me know. Also, this is just for education purposes right and won't ever be done in flight... *rolls eyes* Quote Link to comment Share on other sites More sharing options...
carusoam Posted April 26, 2021 Report Share Posted April 26, 2021 Something to consider... How do you not accidentally end up in the experimental category? Or this is for an RV4 project... -a- Quote Link to comment Share on other sites More sharing options...
TCUDustoff Posted April 26, 2021 Report Share Posted April 26, 2021 @ carusoam For the TN200D, its all TSOd and certified stuff and a valid question. Since neither Brittain or Terra appear to be functional companies, its a valid question to ask since there is no longer technical support. I must assume that, since the original install was done in the 1990s when the company was solvent, that it was done legally per the filed 337. So, obviously, its possible. As far as the G5s, its two wires.... I won't get into my view of the FAA here, but lets just say its for educational purposes only. *edit* Additionally, I am objectively curious about how the different signals appear to function. It seems like GPSS roll steering only adds in the reference heading to allow for adjustable gains and intercepts based on the delta between desired heading and actual heading. An improvement, obviously, to a fixed gain value but not something that would preclude it from working well enough in a VFR environment to reduce pilot workload. Quote Link to comment Share on other sites More sharing options...
211º Posted May 17, 2021 Report Share Posted May 17, 2021 Yesterday was the first day that I flew the Mooney with the Brittain altitude hold working... like it's supposed to. I've attached two photos of pre- and post- Brittain enabled altitude hold. So much learned over the last two months - the pitch control, the altitude hold button... and how to engage both. Such a brilliantly smart system... and frustrating until understood. 1 2 Quote Link to comment Share on other sites More sharing options...
0TreeLemur Posted May 17, 2021 Report Share Posted May 17, 2021 12 hours ago, 211º said: Yesterday was the first day that I flew the Mooney with the Brittain altitude hold working... like it's supposed to. I've attached two photos of pre- and post- Brittain enabled altitude hold. So much learned over the last two months - the pitch control, the altitude hold button... and how to engage both. Such a brilliantly smart system... and frustrating until understood. Sweet! I've got a date to install a Brittain altitude hold system with my A&P at the end of May. Here's a screen shot of me manually maintaining 7500' on a recent trip. Hope to show better results when I repeat this trip in June. 1 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted May 17, 2021 Report Share Posted May 17, 2021 O tree... You didn’t leave any margin for the AI (artificially intelligent) AP to capitalize on! Good luck with the install... Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
0TreeLemur Posted May 17, 2021 Report Share Posted May 17, 2021 16 hours ago, carusoam said: O tree... You didn’t leave any margin for the AI (artificially intelligent) AP to capitalize on! Good luck with the install... Best regards, -a- Thanks Anthony. Turned out my whole trip from CO-AL was entirely VFR. Just as a test I tried to fly like I was IFR and I generally kept it within +/- 100 ft with a couple of lapses. It was so tiring, especially during that second leg when the turbulence started reaching my altitude. The Brittain altitude hold will be such a relief! The "AI" with the Brittain system is a tiny differential in static and reference pressure across a thin membrane. Brilliant system. Very similar to how the German V-2 "buzz bomb" maintained altitude. Like that system, the Brittain system will provide exactly the wrong control inputs when inverted. Legend has it that some brave allied pilot's started flipping the buzz bombs over with a wingtip, which caused them to nose-dive from an inverted position into a stall and crash. Not sure how much truth there is to that story but fun to recount. Data forthcoming, hopefully not from an inverted recovery. -Fred 2 Quote Link to comment Share on other sites More sharing options...
211º Posted June 9, 2021 Report Share Posted June 9, 2021 I've collaborated with several MooneySpace people and created a portal for Brittain system stuff. Disclaimer: there are a lot of variations on installs, equipment, and set ups. If the stuff that you see doesn't match what you have - that is ok, it is just different than what I've discovered. In conversations with my collaborators, we've decided that the "keepers of the system" kept innovating and developing to improve the system - even simple things like mounting the altitude hold chamber to the (interior) skin of the aircraft to better reflected the exterior temperatures (and to reduce time-taking equilibrium of temperatures). To the people who have helped me over the past number of years in understanding and learning about this brilliant, simple, effective autopilot: https://www.windfield.farm/brittain-autopilot Dave 1 1 Quote Link to comment Share on other sites More sharing options...
TCUDustoff Posted June 19, 2021 Report Share Posted June 19, 2021 Quick question for folks; what Amp Circuit Breaker are you using for your B-11 systems? Mine was hooked into an inline fuse holder and we can't make out what Amperage the fuse is; even under a magnifying glass, can't find any markings that reflect the max Amps. Wanting to replace this with a breaker while I am redoing the bus bar and the documentation from Brittain just shows a breaker without any specs. Thanks! Quote Link to comment Share on other sites More sharing options...
Igor_U Posted June 25, 2021 Report Share Posted June 25, 2021 On 6/19/2021 at 6:26 AM, TCUDustoff said: Quick question for folks; what Amp Circuit Breaker are you using for your B-11 systems? Mine was hooked into an inline fuse holder and we can't make out what Amperage the fuse is; even under a magnifying glass, can't find any markings that reflect the max Amps. Wanting to replace this with a breaker while I am redoing the bus bar and the documentation from Brittain just shows a breaker without any specs. Thanks! When I checked, my inline fuse was 1 amp. Quote Link to comment Share on other sites More sharing options...
0TreeLemur Posted June 26, 2021 Report Share Posted June 26, 2021 On 5/16/2021 at 11:33 PM, 0TreeLemur said: Sweet! I've got a date to install a Brittain altitude hold system with my A&P at the end of May. Here's a screen shot of me manually maintaining 7500' on a recent trip. Hope to show better results when I repeat this trip in June. Here's what happens with the Brittain AH II system installed The first half of this leg was 1/2 in building cumulus at 8,000 ft dodging thunderstorms. The second half was flying through moderate to severe turbulence in western KS and eastern CO. Love this system! Note: changes in pressure altitude associated with going from 29.73" pressure to 29.90". Groundspeed variations due to turbulence. It was rough, yet the altitude hold worked flawlessly. 1 1 Quote Link to comment Share on other sites More sharing options...
Raymond J1 Posted June 26, 2021 Report Share Posted June 26, 2021 And this technology dates from 1933-1937... Thank Brittain industries. 1 Quote Link to comment Share on other sites More sharing options...
0TreeLemur Posted June 28, 2021 Report Share Posted June 28, 2021 On 6/26/2021 at 3:51 PM, Raymond J said: And this technology dates from 1933-1937... Thank Brittain industries. Can you provide a reference? I'm very interested in the history of this technology. The earliest patent I've been able to find is the Clarkson wing leveler patented in 1958 that Brittain purchased. I've heard rumors that the Brittain altitude hold system is similar to what the Germans used for on the V-2 "Buzz Bomb" to make it fly at constant altitude. Quote Link to comment Share on other sites More sharing options...
Raymond J1 Posted June 28, 2021 Report Share Posted June 28, 2021 The first autopilot was invented by Sperry in 1911-1912. http://fly.historicwings.com/2012/08/george-the-autopilot/ The use of pneumatic energy to act on the control surfaces is due to the RAE of Farnborough who first adopted this principle on his Robot Air Pilot missile in 1930. For the management of the flight in heading and altitude, the evolutions of the autopilot are related to the work of George DeBeeson, hence the nickname "george" given to the autopilot. http://www.debeeson.com/untoldstory/index.htm In 1937, the electro-mechanical DRU (Dive Recovery Unit) was created for the JU 87, using barometric pressure to calibrate an altimeter trigger. 2 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted June 30, 2021 Report Share Posted June 30, 2021 Way to go JR! I thought George was Sperry’s first name… Now I have that straight. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
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