Beaver Tips

[xsbank]

"Ex. 20 — Illusions Created by Drift

(1) During a turn from into-wind to downwind during flight at low level in high wind conditions, a dangerous illusion may affect your flying.

1. What is that illusion?
2. Why is it dangerous?

(2) When flying downwind at low level in a strong wind:

1. What illusion may be experienced?
2. Name a condition where this could be dangerous?

(3) When turning from downwind to into-wind, the actual path of flight will not necessarily follow the still air flight path. Why?"

[beaverbob]

Good reply, XS.
To the rest of you I don't think anybody suggested that a plane stalls at a higher IAS or TAS or any other measurement of airspeed during a turn to downwind as opposed to into wind.
However for a VFR pilot looking out the window in these conditions it must be remembered that an aircraft does stall at a greater Groundspeed when turning to downwind and appears to be slipping towards the inside of the turn. The effect of this combination called drift illusion has caused many pilots over the years to slow the airspeed to the point of stall even thought the visual effect is of a greater speed and to push on the rudder pedals to the outside of the turn, causing an unco-ordinated skidding turn and a resultant classical stall/spin accident.
The resultant stall and subsequent spin,(usually to the opposite direction of the turn) is quite a shocker to all on board and could be the last great shock of your life.

This whole turn downwind turn thing was to remind everybody about an illusion that has caused much loss of life over the last 100 years of flight.

Think about it.

Bob


And Stearman, Than you for the acknowledgment

[Slats]

Carb heat: Never had any trouble with carb ice in the Beavers I've flown but I've always tried to keep the carb temp in the 4-7 degree range regardless. The only exception is when that extra bit of power was necessary, ie-heavy load, hot temps and high altitude.

Starting: Was taught by a guy with thousands of -2 hours to hot start with a few pumps of the throttle. Never had any issues starting using either technique.
On a slightly different note, I was taught to start with mixture full rich....does anyone start with the mixture ICO? I've seen this done with mixed results.

Take-off power: Heard both sides of this argument numerous times. I understand the side of max t/o power but I'm not entirely sure I buy it in every situation. Don't get me wrong, the vast majority of the time I use max take-off because the vast majority of the time it's what the situation dictates, but what about when you're empty and into a 20kt wind and you know you'll be off the water in ten seconds or less. Furthermore, what about those winter days when it's -25 degrees and you're empty on wheels taking off into a 20kt headwind and you're airborne before you even get to take-off power let alone max take-off power? In a situation when you know your machine and you know that you will be airborne very quickly, so quickly that the difference in t/o time between 36.5 vs. 33.5 or even 30 inches will be nonexistent, what's the problem with going directly to max continuous or even climb power setting rather than setting a power setting only to change it seconds later?
Just to play devil's advocate.

[beaverbob]

Carb heat: Never had any trouble with carb ice in the Beavers I've flown but I've always tried to keep the carb temp in the 4-7 degree range regardless. The only exception is when that extra bit of power was necessary, ie-heavy load, hot temps and high altitude.



In a situation when you know your machine and you know that you will be airborne very quickly, so quickly that the difference in t/o time between 36.5 vs. 33.5 or even 30 inches will be nonexistent, what's the problem with going directly to max continuous or even climb power setting rather than setting a power setting only to change it seconds later?
Just to play devil's advocate.

What is wrong with getting off the water a quickly as possible? If you operate your throttle correctly in a light load high wind situation you might get airborne before full throttle. But that should not be the plan.
For safety sake use take off power until airborne and then max continuous until established in a safe climb. Remember that not all hazards in the water are visible.
I'm tired of repeating myself about the proper start and prime methods, so no response there.
You are correct about the carb temp, except don't forget to lean slightly to compensate for the hot intake air. And Beaver engines can get lots of carb ice. A simple rule of thumb is to set cruise MAP and then add carb heat until a loss of 1/2 in MAP is noted and then reset throttle and lean.

Bob

[Slats]

Sorry Bob, didn't notice anything regarding mixture position on starts in previous posts.

[beaverbob]

Sorry Bob, didn't notice anything regarding mixture position on starts in previous posts.

Forgot to mention that. Just prime and start with full rich. Hot or cold.

[bronson]

P&W put out a bulletin on reduced power T/Os years ago, can't remember if it was an SB or what. They say don't do them and then go on for a couple of pages as to why not. This applied to the 985 and 1340, not sure it would apply to the -3 where you're using 50" or more though. Alaska used to use full throttle routinely for T/O in the Goose...mind they had their own overhaul shop!

[Stearman]

I guess what I am trying to say about this advice about turns from down wind is how does this apply as a Beaver tip?

If we all agree that an airplane Stalls the same...well minus the few people who seem to think differently in th earlier posts from what I recollect.

This tip about "illusions" is no different from any other airplane any of us have flown. Like someone earlier said it would be in the flight manual if the Beaver was more at risk flying downwind then most.

Anyway if anyone has any good Meat and Potatoes kinda of tips to post go right ahead. But please no Ice Cream! Will leave that for the kids.

Beaverbob do you have any recomended MP setting for maintaing a Step taxi when empty?

[beaverbob]

Regarding Step taxiing, I don't look at the gauges, just out the window and apply power as required.
I retract the flaps and keep looking at the water ahead.
Bob

[Slats]

Step taxiing requires a reduced power setting and is therefore akin to reduced power takeoffs and therefore should never be attempted.

Seriously though, there's no hard numbers for that kind of thing.....look outside and set the throttle, as required. You'll know when you have the right setting, you'll feel it. If you get a sinking feeling, you need more. If you start feeling light, you have too much.

[beaverbob]

Hi Stearman,

This stuff about turns was off topic, but I never brought it up, only responded to it when in became incorrect.

There is one important thing about turns with a Beaver though; Never turn with more than 30 degrees bank without a small amount of flaps extended. People have died by stalling a Beaver in a steep turn. The stall speed and the airspeed meet quite rapidly in a loaded Beaver during a steep turn and the straight wing stalls quite violently from a steep turn into a spin. if I seem to emphasize this it is because I lost a good friend from this.
This is what other pilots were trying to get to when discussing the turns.

To transition from landing to step taxi, As soon as the plane is on the water I pull throttle back to make sure it is stuck on, then as the speed diminishes retract the flaps.Then reapply some throttle all the while looking out the window to watch for obstacles and make sure the plane does not fly.

As far a docking goes, shut the engine off with mags only. Then if you shut off too soon the plane will restart instantly without priming. Try sutting off too early and you will probably be suprised at how long the plane will drift along on the water. Taxi to the dock with one mag and carbheat hot.

If you are taxiing onto a strong wind and have to turn downwind towards the dock, you will notice that the plane turns until about 90 degrees X-wind and then tries to weathercock. At thai point extend the flaps fully and turn the ailerons in the direction you are turning. Then the wind will push the down aileron and flap from behind and finish the turn for you.I am surprised how many pilots don't know this.(from my observations at AM9)

Sometimes you will be required to takeoff down wind. As you arrive onto the step and the nose comes down you might experience a strong weather cocking tendency, even greater than the rudder can correct. If this happens pull the nose up hard and high momentarily and re-lower it when the weathercocking yaw is stopped. When the nose is high with a tailwind the weather cocking tendency is fortunately opposite of when it is low as on the step.The wind actually pushes the plane straight ahead with a nose high atitude and therefor you can keep straight. Practice this by step-taxiing downwind and raising and lowering the nose and paying close attention to when yaw occurs and doesn't occur.


Bob

[flyinthebug]

beaverbob.. ALL really good tips! One question though..I was also taught that a mag shut down on the -2 a) left raw fuel in the cylinders and hence caused a washing of the walls and subsequent flooding. By adding more raw fuel (using your method of primer only and no pumping of the throttle) wouldnt that be a recipe for flooded starts?..

I know drivers on the wet coast with 1000`s on the -2 and they still pump em to start and shut down with ICO. That said, I have started them and shut them down both ways.. If I had a difficult docking, then mags to shut down, but was always taught from day one to use the ICO to shut down a R985 to ensure you burn off what raw fuel would be left in the cylinders.

Im no AME but that was how it was taught to me as well.. A certain CP on the coast would have had a FIT if you used mags to shut down..It was never allowed at the base in Nanaimo anyways.

Other then that beaverbob you are 100% on the money. And again, I dont disagree with you..I am only pointing out that other operators teach you to pump to start and ICO to shut down and dont dare deviate from that. Id be curious to hear your reply.

My tip for the -2. Never EVER believe your fuel guages on a -2 and if you are in the bush, carry a 6 foot long hose and DIP your tanks. Make sure! The extra 2 mins it takes during your DI to confirm fuel load is well worth it.

Fly safe all. Cheers

[beaverbob]

You are correct about the fuel cylinder wash when shut down with the mags. However most of the commercial seaplane flying is stop and go and if a restart is within the next 5 or 10 minutes then that is not a problem. This also eliminates the need for any priming of any kind, - throttle or prime. Instant start within for first 10 minutes or so after shutdown. I have done this for over 20 years and on my own beaver never even changed a cylinder in over 1200 hour on the engine by the time I sold it.
I have also been told by an engineer that if I shut down with mags and then pull the mixture right away, that will help reduce cylinder wash. Is he right? Not sure.

As far as pump start the throttle, I do not know how any operator can actually require this method. The book even only mentions how to prime and makes no mention ever about pumping the throttle, except not to pump the throttle to catch a dying engine.
You can catch a dying engine with the primer though.
And, yes, I know lots of pilots do this, but go have a look at a Beaver engine on a shop floor one day and figure out where the fuel goes with the different priming methods. The carburetor is on the bottom and any excess fuel is going to go with gravity. Is that correct?
Bob

[beaverbob]

About shutting down with mags only, I just reread my previous couple of posts and realize I implied to shut down with mags only. That is the wrong assumption. What I meant to say was if there is any doubt about making a dock, considering current, wind etc then the mags allow for a quick restart if needed. The ICO just takes longer to shut off the engine if you waited too long.
Bob

[flyinthebug]

Thank you for the clarity & reply beaverbob. I have learned a few things from this thread. Cheers!

[Lurch]

Awsome advise but can you further explain these two things

Taxi to the dock with one mag and carbheat hot.

I'm having a hard time picturing the aerodynamics of this one

Sometimes you will be required to takeoff down wind. As you arrive onto the step and the nose comes down you might experience a strong weather cocking tendency, even greater than the rudder can correct. If this happens pull the nose up hard and high momentarily and re-lower it when the weathercocking yaw is stopped. When the nose is high with a tailwind the weather cocking tendency is fortunately opposite of when it is low as on the step.The wind actually pushes the plane straight ahead with a nose high atitude and therefor you can keep straight. Practice this by step-taxiing downwind and raising and lowering the nose and paying close attention to when yaw occurs and doesn't occur.

Thanks

Lurch

[Meatservo]

Hi Lurch,

I had to think about it for a second, but his technique for dealing with a scary swerve while taking off downwind is correct-at least, this is also what I do in a downwind takeoff, when I do one, which is rarely. I think the plane is directionally less stable while on the step downwind because it gets on step at the same speed through the water regardless of direction, but the airspeed will be lower going downwind, hence the vertical stabilizer is less effective until the plane accellerates. The act of pulling the nose up moves the centre of buoyancy aft, and I believe this will make the floats themselves more directionally stable until the aeroplane accelerates to the correct airspeed. In a boat, the farther aft the centre of buoyancy, the more she likes to point downwind. I think this principle applies in this case, as pulling back will cause the centre of buoyancy to move aft. Once the plane's airspeed increases, of course, it will regain its own stability. I've noticed that on some types of aeroplane, the speed through the water needed for the floats to come up on step is close to the airspeed needed for the flight controls to be effective, these planes are very stable directionally during takeoff. If the "step" speed is significantly slower than that, they will be less directionally stable during the takeoff run. I'm sorry I sound so pedantic; I'm thinking it through as I type.

I think the reason or taxiing to the dock with carb heat and one mag is just to be able to slow down even more than regular idle, if you want to approach the dock more slowly than usual for whatever reason.

[Meatservo]

Just thinking about it some more, the "centre of buoyancy" thing works too, if you're trying to turn an aircraft with a big tail downwind while taxiing, and she won't make it through the turn, pulling back at the same time as adding some power will sometimes make the plane more willing to point downwind. An aft C of G will make a plane more willing to point downwind, too. Sometimes taxiing an Otter, getting a couple of people to run aft while trying to make the turn downwind will help her to make the turn. Of course they have to get back in their seats for the takeoff!

[Stearman]

All excellent tips again BeaverBob.

Thanks!

As for the 1 Mags and Carb Heat Hot...you are lowering your RPM so that you can approach the dock slower if that helps.

And for you guys pumping the Throttle during start maybe you guys should carry a fire guard on the float.

I am going to leave the downwind T/O to the experts for now till I get some more time on her.

[GUMPS]

Where abouts did you get this part time gig if you dont mind me askin stearman?

[Lost Lake]

Cold weather starts with a bottom air intake. AS soon as it starts, carb heat on. The heated air will offset the cold air intake and it will idle easier, reducing the need to keep priming.

[xsbank]

True, perhaps, but if you pooch the start and she backfires you may damage the intake with carb heat on.

Pump-start works fine on the small Beaver radial but it will blow up a larger one like an 1820 or 1830+. Don't know what will happen with the Otter as I've never tried it but that geared prop can cause high manifold pressures - besides, we are not talking about Otters.

[phillyfan]

If you blow a tank, throw 5 gallons in after you land. A tank blown in cruise will still have enough fuel to get you airborne and up to about 100-150 feet. Thats a bad time in a Beaver to have the engine quit. Your don't have a whole lot of extra speed to play with and that speed goes away pretty quick without the engine. If you put in 5 gallons it might blow high enough that you have a fighting chance of getting things figured out. Especially if a bunch of diferent drivers are using the same airplane. What's 30 or 60 lbs in added weight. Take it out of the pax's shit.
Same applies when you can see up ahead that the weather looks like shit. You know your gonna be spending some time down low with your nose pressed up against the dash trying to see where your going. Just switch to the fullest tank so you don't get a surprise. I know, I know the regulars will tell you that things like this never happen to them and hence should never happen to anybody, ever, but these things do happen and I speak from experience.

[flyinthebug]

If you blow a tank, throw 5 gallons in after you land. A tank blown in cruise will still have enough fuel to get you airborne and up to about 100-150 feet. Thats a bad time in a Beaver to have the engine quit. Your don't have a whole lot of extra speed to play with and that speed goes away pretty quick without the engine. If you put in 5 gallons it might blow high enough that you have a fighting chance of getting things figured out. Especially if a bunch of diferent drivers are using the same airplane. What's 30 or 60 lbs in added weight. Take it out of the pax's shit.
Same applies when you can see up ahead that the weather looks like shit. You know your gonna be spending some time down low with your nose pressed up against the dash trying to see where your going. Just switch to the fullest tank so you don't get a surprise. I know, I know the regulars will tell you that things like this never happen to them and hence should never happen to anybody, ever, but these things do happen and I speak from experience.

Well said, me too!

[Lurch]

If you blow a tank.

Lurch