Cessna 208 Caravan Amphibian: taxiing?

I was trying to find a nice payware a/c, but as far as I can see even Carenado don't do one. No matter, the FS9 one is fine... but does anyone know of a tweak or bit of software that would make taxiing (i.e. getting from water dock to water runway) more realistic? At the moment you need quite a bit of throttle to get the craft moving through the water, but then it surges forward at a rate of knots (20-30 of them) and pulling back on the throttle brings the a/c to a halt.

On land, all is fine of course, but in the water... Maybe there's a technique that's eluding me?

Thanks.

This has long been an issue with amphibs in FS9, especially the 208; I've had a couple of add-on aircraft where once you gave enough throttle to start moving they would take off before you could reduce the throttle.

A couple of older threads which discuss possible workarounds:

https://www.avsim.com/forums/topic/28389-caravan-amphib-handling/

https://www.avsim.com/forums/topic/252485-floatplane-water-handling-characteristics/

I've never tried amphibians, but a suggestion from landplane experience...

Turboprop engines tend to have a difficult relationship between throttle position and torque, especially at low throttle settings. Thus, I can easily imagine that you can't find the goldilocks throttle position that is not too much and not too little.

The solution is in 'engine condition'. In the real world it is a lever, like the throttle, that varies between max torque (for in flight) to minimum torque (used for ground taxi) to completely off (cuts off fuel to stop the engine). In FS04 this is the same lever used as mixture control for a piston engine (I assume you have a throttle quadrant with levers for throttle and mixture). To taxi set the throttle to a position that is about right (trial and error here) and then make fine adjustments with the mixture control.

Hope this helps!

Nadlzfw

Hi Folks,

It's not the plane it's the water. It's just poorly modeled even in the latest sims... Any RW plane on floats - if the propellor is turning the plane is moving - there is no drifting in the sim - the water is like concrete - I haven't come across anything to even remotely simulate seaplane physics - so I just avoid them...

Regards,

Scott

Sent from my iPad using Tapatalk

Hi Folks,

 

It's not the plane it's the water. It's just poorly modeled even in the latest sims... Any RW plane on floats - if the propellor is turning the plane is moving - there is no drifting in the sim - the water is like concrete - I haven't come across anything to even remotely simulate seaplane physics - so I just avoid them...

 

Regards,

Scott

 

 

Sent from my iPad using Tapatalk

I know we're talking different sim software here but, I often fly the default Beaver in FSX Acceleration and it seems to work very well. Having said that, the only RW float-plane I've flown is a CH-46 and choppers obviously don't handle anywhere like fixed wings, except maybe at straight and level cruise speed.

With the Beaver, if you don't back off the prop, it will creep even at idle. And if you don't drop the water rudders, it is very hard to steer during taxi. Also, as I've experienced many times RW in a boat, there is considerably more drag in the water than on land. Water is pretty viscous.

Overall, I consider the handling of the Beaver in water much more realistic feeling than any chopper I've tried to sim. So I enjoy flying among the fjords with the Beaver but avoid sim choppers like the plague.

Michael

So many variables! I already have the props and the condition levers mapped to my Saitek X52, so I can easily vary the settings. It seems to me that part of the problem (or even 'the' problem) is that, no matter what the condition lever setting, I have to put a lot of throttle onto the a/c to get it moving in the water (which is logical of course, compared to resistance on land). It is then very slow to respond to a reduction in throttle though, so that once you get moving and have some momentum, you are at 20 kts before you know it, and there's nothing you can do about it. (Or is there???? .....)

Thanks for the continued input folks.

Hi Martin,

Forgive me for bgutting in but Rupert above says he flies the FSX default Beaver and it seems to work not too bad, do you have FSX?

If so it may be possible to use some the aircraft.cfg from that and edit it to use on the 208, I've used a few cfg's from FSX on FS9 models to make them fly better so it does work, just a thought mate.

Col.

The only thing I know of that may help is to alter the sensitivity on the throttles and set the Null Zone set to nil this will stop any drift on land and make overall handle on both land and water a lot easier.

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Hi. Yes, I do have FSX, although I rarely start it up these days. Interesting idea - I can try out some of the settings in the FSX aircraft.cfg files (even the .air files?) with the FS9 planes and see what happens.

I don't think the nul zone will change anything in practice - to get the c208 moving in the water I have to push my X52 to well over half way forward to get any timely response, and then, when you pull back as the a/c starts moving, the effect is delayed enough that you have reached 25kts before it starts to slow down again.

I have tried being more 'patient', and just waiting (and waiting) for the a/c to start moving on the water with less throttle input than that, and if you have advanced the throttles far enough, and wait long enough, you do get forward motion, and the speed is more controllable, but it's far from ideal even so.

OK, I hadn't given up on this....

I tried settings from the FSX Beaver, but without any success, so I had a look, line by line, at the C208 aircraft.cfg file and tried changing this line:

static_thrust =158

to this:

static_thrust = 1000

I had thought such a large change would render the a/c unusable - but no, it now starts moving in the water with far less throttle and is much more responsive to small throttle changes too. In the air, it seems to be fine as well.

On the ground the a/c seems no more lively and with throttles at idle, it stays still without brakes.

Maybe someone else could have a go and see how they find it... I haven't really tried values apart from 1000 yet, maybe there's a better figure. Or perhaps there are some drawbacks to changing this value that I haven't noticed??

Good job! Simmers usually jack up the static thrust to get faster acceleration and higher top speeds with the turboprops. I converted a DHC-2 from piston to turboprop and it behaved a lot better in the water. Video:

There are a couple of things you can do for better handling. I remove the 'type 5' (water rudder) cnt pts and just add steerring (30.000) to rear most floats. The other is I add lots of drag in air file (1200.000000) to the spoiler. This will act like 'brakes' when in the water. I also change the compression values (8, 9, 10) to '0.100, 4.5, 1.000' for all floats. Also I change the cnt pt sound (13) to '4' (will hear water splashing).

Sounds like you know your way around the cfg and air file. I have been doing it for 15 years and occasionally still learn something new. I edit cfg & air files every day. I don't have a C208 on floats anymore (HDrive crash in 2012) or I would 'test' your tweak. Cheers.

Chuck B

Napamule

Edit: Found my C-208 in FS9 video: https://youtu.be/c5x2BN35w1I . It's 'hot' (on purpose) so could be tamed down. Pontoons look / sit high but can be loweered.