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airbusguy

Towing a FFH

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I still have the key start on my 2010 FFH. I am old enough to remember on the 1940 cars they had push button start, then the key start came in in the 50's which was considered an upgrade, but it was on the dash, not the steering column. Then when they wanted to lock the steering wheel when off and in park, they put it on the column. Anyway, I have never considered the push button start to be a feature, just an annoying change back to an old concept. Maybe your FFH needs a way to totally disconnect the HV and LV batteries, but as you say, very few people tow their FFH's. I'm sure some of these experts on this forum can help you with that.

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The 12 vdc is charged from the HVB by the dc to dc converter. In "N", the HVB can't be charged so the HVB shuts off when it gets to it's emergency low shutoff point. The 12 vdc then eventually dies. There is always enough left in the HVB to start the ICE after you've jumped the 12 vdc. What about keeping the 12 vdc charged from the towing vehicle? Maybe it's as simple as plugging into the 12 vdc "cigarette lighter" outlet. Connecting to the "jump" points should work.

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How about pulling the plug on the HVB and disconnecting the 12v? Only downside is it wipes he computer when you do. I second what Lolder mentioned, your RV should have a +12 accessory feed on the 7 pin plug, you could adapt a harness to wire into the jump point under the hood to keep the battery charged. The car will be powered off the RV for the most part then.

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I think the big alternator of the RV might not be able to fry the FFH battery through the wire gauge of the towing harness. You could also put in a dual battery charging system but the simplest way would be to put a big ( 30 Amp) silicon diode on the charge line to the FFH system. That would introduce a relatively constant 0.7 vdc drop in the voltage. If the big RV alternator was putting out 14.4 vdc that would put 13.7 on the car which wouldn't harm it. Get one at Radio Shack for a few bucks before they go out of business or shop here: http://www.mouser.com/Semiconductors/Discrete-Semiconductors/Diodes-Rectifiers/Diodes-General-Purpose-Power-Switching/_/N-ax1mp/?gclid=Cj0KEQiA592lBRCXy8yl4bjK17wBEiQAg1Az_Xs5u7FMekBfncCISJDPUCx25PngYl0Cy-TTZvFDi0kaAlbA8P8HAQ

This would be a Mouser part # from above site: 863-MBRB3045CT-1G

These might need a heat sink.

Edited by lolder

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The diode from "Mouser" is the quickest and cheapest solution. It looks like it's just over a dollar plus shipping. I've bought stuff from them before and they are legit. I don't think RS has filed yet but I don't see any big diodes in their on-line catalog anyway. If you're an Airbus guy you should be able figure the electronic stuff out.

 

At my monthly retired old captains lunch today, Airbus came in for the usual flak from the Boeing, Douglas, Lockheed and Convair ( me ) pilots.

 

Same old score: Thunderstorms 10 :: Airbus 0. There's an emergency AD out on the A 318-321s about upsets and loss of control requiring rapid circuit breaker pulling for two of the three air data systems when they are having icing or other glitches.

Edited by lolder

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Remind me to stay off big planes for the time being. :)

 

RS going under? Not really surprised, their time has passed since no one builds electronic kits anymore, and MP3 players have pretty much made home entertainment stereos obsolete. Last time I went in for electronic parts, they had very little in stock. I needed some 9 pin serial ends for my RC stuff, and they had a total of 2 female and 1 male. That and the people working there look cross eyed at you when you ask them for some electronic part. Want to confuse them to no end, ask for a flip flop ic.

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What I can't figure out is how to delete a ghost quote due to my fat fingers on my phone's keyboard :)

Sometime around 1970 when I was co-pilot on the DC-9, they added a "pitch hold" to the auto pilot that had no air data input. It was to be used if you were so improvident as to get yourself in turbulence and was the solution to jet upsets. The Airbus has that doesn't it? I used it once in moderate plus turbulence descending though a smooth looking cloud layer associated with a deep low that i had been warned about by ATC. Used full ignition and anti-ice and had the FA's secure everything well in advance and everything was fine but it was really rough and would've been hard to hand-fly. No sustained up or down drafts. The layer was about 5K feet thick and looked as smooth as stratus.

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You had to hand fly a B-17 in formation but it had an auto pilot that was used by the Norden bombsight and the lead aircraft would use the auto pilot. When not in formation the auto pilot could be used. It did not maintain the altitude. Most modern aircraft auto pilots can land the aircraft. They do it pretty smoothly most of the time. First World pilots seldom use that feature except when required by very low cloud ceilings and visibility when it's use is mandated. "Auto land" has been around about 50 years in some aircraft and is widely installed today.

 

It's usually foggy and the runway is wet when auto land is required so there is very little initial friction when the wheels hit the runway and spin up. Sometimes the only way you can tell the aircraft is on the ground is the cockpit control handle for the automatic wing spoilers moves on command from the wheel spin up; it's that smooth.

 

What has this to do with towing a FFH. Soon you'll be able to tell it where to drive as an autonomous vehicle. These technologies are farther along than most people know. Auto land systems are for the most part "Fail-operational" which means they can tolerate a major component or aircraft system failure and complete the landing. The pilot doesn't have to suddenly grab the controls. GOOGLE has realized this and plans the same philosophy, People are poor backups for real-time automated systems.

Edited by lolder

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Yep, knew that. Our cars are so close to auto drive now, it is scary. The only thing missing are road markers the car can see at all times. Now do pilots do regular sims where they have to fly the plane, as in a complete systems failure where you are basically on the same level as a b-17?

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