Motorizing Homemade Throttles

[matta757]

Hey Jack,

I think Mike was posing that as an "imagine if you need to abort takeoff" type thing... I don't want these so I can sit back and watch them move instead of me moving them... but that being said, it is realistic that from the moment you engage A/T on takeoff and the levers move themselves forward they remain under the control of the A/T usually until landing, at which point you disengage and manually operate.

The reason I want this feature is so that when the aircraft finishes climb, begins descent or makes any other autothrottle adjustment my thrust levers are ALWAYS where they are in the game, so that when I do disconnect them, the thrust settings are in the same spot and don't all of a sudden jump up or down when I begin to use them manually, if that makes sense. I think it will be quite awesome to see the levers retard slightly when the aircraft levels at the top of climb... and being that it's what the real aircraft does, wouldn't that be the epitome of realism?

I do understand your desire to manually control things, and I too love that and am not giving it up, but being honest, once I engage the A/T on the runway, I don't manually operate the throttles again until landing!


Matt

[jackpilot]

It is of course a never ending debate but what a kick to fly manual!!!
Well I am an oldie, probably, used to engage the AP well over 10K, when it worked, and always watching and not trusting that alien gizmo!!!
(was another planet, because one of the reason to engage it was to put the feet up and light up  a Camel !)
Have fun Matt, that 's all it is about.
Jack

[matta757]

Jack,

Did you fly commercially? What aircraft(s)?


Matt

[MLeavy737]

Jack, Not much has changed other than the fact that we usually have the autopilot on below 10k and you can trust it.. oh and forget about smoking lol.

Yeah i didnt mean that you have to constantly override the autothrottles as if they didnt work correctly. They really work perfect but the times i override them is usually a matter of technique and or staying just a little bit ahead of the airplane.

I think the servo idea would definately work fine. My biggest concern would be the damage that could be done if you or someone else reached up and yanked them around without realizing. I could just see myself sitting in the instructor cab setting the crew up for a Rejected Takeoff.. Aotothrottles engaged, TOGA, power comes up nicely, 100k... (Boom, engine fail).. captain reaches up and slams the power to idle then disconnects the autothrottles.. I can hear the servo gears crunching away!!

If your just doing it for looks and you keep that in mind i think servos would be fine. If you plan on doing any kind of training or have other people fly your sim then i would try and go the dc motor/clutch route.

Mike Leavy

[matta757]

I often times fly up to even 18,000 manually... I love handling the plane, so no need for automation there.

I am actually leaning towards DC just because it appears to be smoother movement.

[MLeavy737]

yeah it is fun to actually fly once in a while

Mike Leavy

[Atomic_Sheep]

I was just wondering if anyone knows whether the embraer 170/190/175/195 aircraft use a similar DC clutch/break setup for their authrottles?

[MLeavy737]

I was just wondering if anyone knows whether the embraer 170/190/175/195 aircraft use a similar DC clutch/break setup for their authrottles?

I dont think there is much variation in how real autothrottles work in different airplanes... (Airbus not included) I dont know what that thing does with its clicks..  But you always need to be able to override, engage, and disconnect an autothrottle. Only so many ways you can do that.  Anytime you override it, it has to come back to its calculated position.  To me the motor/slip clutch method is the absolute best. Direct servo driven autothrottles are a disaster waiting to happen. 

Mike Leavy

[Atomic_Sheep]

I totally agree with you when it comes to servo solution. I've been involved in RC airplanes as a hobby when I was younger so I know what servos are. I've dismantled them, broken em, fixed em etc... and I totally agree that it's an absolutely inappropriate tool for the task.

In terms of the Airbus one... it's quite simple, I don't know 100% but from what I understand and experienced in a real flight sim (only had the chance to do so once... I'm no pilot unfortunately), from idle all the way to the max that the levers go, you select the thrust you want... simple enough... same idea when going in reverse... have to pull some stuff to allow you to get into that range. So all this is pretty straight forward so far. Now the gates. All the gates are, is bumps that you feel and a click that you hear when you reach one. If you're in it, I'm guessing some button gets engaged inside which tells the computer that the thrust levers are in a gate. If they are in a gate, then the computer controls the thrust. The fact that there are different gates simply means that in order for you to tell the computer to execute certain commands, you need to put the thrust levers in appropriate gates otherwise the computer is locked out of those commands. It's pretty confusing if you have never used them but once you get used to them, it's actually a very intelligent system. But yer in terms of confusion, lets say you are travelling at 250 knots and you are currently in manual mode i.e. not in any gate, then you decide to crank the speed up a bit so you push the throttles forward but you don't realise you've hit a gate (very hard to do because it's so obvious so I would say impossible but lets say for arguments sake that you did not notice that you entered a gate)... lets say that gate is active and the airspeed setting chosen by the computer is 220... therefore... despite perhaps moving the thrust levers forward, since you've entered the gate, the computer will actually decelerate the plane. So that's one example of where one might get confused. The other cool thing about the airbus system is that when you put the thrust levers into a gate (lets say CL) which is the climb gate and the gate in which the levers are in 99% of the time, well... in that gate, you don't even need to control the airspeed of the aircraft manually i.e. you don't need to touch the airspeed selector knob from the moment that you take off to the moment you are on final as long as you've programmed the route with all the airspeeds in before the flight... it does it for you. Very simple and powerful system.

I will admit, it was all so easy that I got quite bored! Very awesome fool proof design however, great respect for it and honestly believe it's a very safe system which we'll be seeing a lot more of in the future. Very intuitive once you get used to it... like anything I suppose.

[matta757]

Regarding the Airbus system, your summary is on point. And for the most part, it is an amazing system you are correct. But at the same time, and seeing as the wreckage was just found, I have read and spoken to some pilots who feel that the lack of a motorized autothrottle could have contributed to the Air France 447 A330 accident. The thought is that given the reports about false speed readings and all that, the pilots may not have noticed a reduction in engine power that they might have noticed if the autothrottle was indeed motorized.

I also am not sure if the Airbus non-motorized throttles will ever take off. Embraer and Boeing (and I believe Bombardier) still use a motorized throttle system. I feel like this is probably because pilots can use the levers as a reference for what their engines are doing. But I could be wrong. I don't want to start an Airbus vs. Boeing argument here, I think both designs have their merits.

[Atomic_Sheep]

Interesting points, I hadn't considered some of the things you pointed... about to look up news of the 447 findings... have been eagerly awaiting more news about it.

EDIT: Another question just popped up. Since I've never experienced autothrottles before in a real aircraft, I was just wondering a little bit more as to what they feel like? The way I understand it, whether the autothrottle is on or off doesn't change the feel of the throttle levers? i.e. the friction level is the same regardless of whether the autothrottle is on or off? Also, I take it that the only thing that the autothrottle switch actually turns on is the DC motor which is connected to the throttle levers? And that is in turn controlled by computers. So basically this second bit backs up the first one if I'm correct in my assumptions?