Author Topic: Which floats?  (Read 4751 times)

Kevin Dunn

Which floats?
« on: October 02, 2018, 08:58:10 AM »
Greetings,

I know there are opinions out there on which make/model of floats work best on a H295 with a gross weight increase kit. I'd be interested in hearing what you all have to say.

Straight and Amphib.

Thanks in advance,

Kevin

xeyes

Re: Which floats?
« Reply #1 on: October 02, 2018, 03:23:00 PM »
I have a set on Pk3500C on my 395 and I don't believe they are as forgiving as Edo 3430's and eventually my goal is to make the switch. I've only flown 3430 once and the AC was light with less then half tanks, I've yet to match the same take off performance with my 395 set up. I have had a fair amount of time in the last two years with my PK's. Flying light with less then half fuel technique is not as critical. The problem with the PK's is I can't rotate enough to get the angle of attack my Helio needs before my heals drag sucking me back down. The Edo's have a longer keel and a short heal so this is less of a factor. Flying light both just blast through this stage but not the PK's not when your heavy.

My heavy take off technique.

Full Flaps
Full power by the count of four staring at 1400 RPM
Full rt rudder
Yoke all the way back till you can push it over onto step (6-12 seconds depending)
Neutral position with the yoke once your on step, find the sweet spot and accelerate watching your airspeed indicator. You can feel the health of your run but it helps to watch the numbers.
Retract flaps 5-7 turns (reducing drag)
Dial prop out 3100-3000 ( I need 60-65 mph before I can rotate, I could never reach that speed as fast with a flat prop at 3400 rpm
At this point I rotate not strait back but more of a slow rolling motion to the right picking my left float first. When you feel it come off you will accelerate slightly due to less drag from the water. I then bring the yoke straight back. It will fly but it still wants to settle on you until you get to about 75-80.
 Now here is the part where I've scared the shit out of my self you need to accelerate to a point to get your slats in before you attempt to climb out. Heavy it will climb every so slightly to a point then nothing, then you start to mush as the trees are approaching.

I think it would perform much better if I changed the AOA between the floats and the Aircraft but there is no free lunch and my cruise would suffer.

Hopefully others will chime in on this.

I have a set of PK3500's I'll sell you....Ha
Ben


Louis

Re: Which floats?
« Reply #2 on: October 05, 2018, 06:56:38 PM »
I think it would perform much better if I changed the AOA between the floats and the Aircraft but there is no free lunch and my cruise would suffer.


We have a way to do that: more flaps.

Before, with the 800, each take-off was an adventure. There was a limit of 20 degrees of flaps on floats. Keeping it straight at the beginning of the course was a challenge.  The plane wanting to go left.  Pushing hard on the rudder.  Then the heels were dragging when i wanted to rotate. Finally, when it was flying, it was with the slats pop out and the plane close to be behind the power curve.

So i decided to change the AOA.  Big job.  Did cost a lot. 

One day, my motor flaps was out of service  ( electric flaps on the 800 ).  I was going for a trip.  Without the flaps, i was sure it would never took off.  But i tried.  So much more easy.  Going on the step was faster.  It was like if i had gain a 20% power increase.  Keeping it straight was easy at the very beginning.  It was asking for more speed for the rotation, but it was easy, more positive. 

Then i saw how they di it with the caravan.  No flaps until your are on the step.  Then you put the flaps and the plane goes up.

I tried it on a unmodified 800.  It worked great.  Easy.

I had a limit on the POH of 20 degrees for flaps.  I tried 25.  No flaps until on the steps, then 25 degrees.  The plane was popping out the water.  Putting 25 degrees of flaps, on a wing that have so long flaps like the Helio, is like giving 5 degrees more AOA without any work.

25 degrees of flaps instead of 20 remove that feeling of not having enough AOA with the heels dragging in the water when we try to pull it from the water. But if you put them at the beginning, you can't keep it straight, and it takes longer to go on the steps.

Not putting any flaps at the beginning also works well in deep snow with skis.

When i switched to a 295, i had Wipline 3400 amphibious field approved.  ( LSTC ) Works well.  I still see the difference when i don't put any flaps at the beginning.  By beginning, i mean no flaps until ready to fly.  A lot better too to help going straight.  You don't have to push the rudder as much.  Some energy saved here too. 

On both machine i have electric flaps.  The switch still reachable your hand on the throttle. 

Might be the only good thing about an electric flaps.  But it makes it easy on floats.

Wich floats ?  The Wipline !!  But you would have to convince Wipline to do the STC.  They could use mine to fly test it.

louis
« Last Edit: October 05, 2018, 06:58:27 PM by Louis »

JamesCaird

Re: Which floats?
« Reply #3 on: October 08, 2018, 02:05:29 PM »
Many Thanks for that, Louis-  I will try it on N400HE (H22) as soon as I get back home. I will report back. H22 is on the EDO3500 Amphibs.   
 Could you PM me with your contact info, please?  Did not get that at Greenville,   Many thanks/  Bob Wallace

Louis

Re: Which floats?
« Reply #4 on: October 08, 2018, 09:51:18 PM »
Try a couple of take-off without any flaps.  Once used to it, do the electric flap trick. 

Since you have a turbine, it might do like the Pilatus.  The nose going so high when applying power, you end up on the heels with more surface on the front than the rear.  So it does want to turn.  Having so much of the front portion of the plane out of the water, the wind in the face want's to turn you.  So don't pull as much as you would do with a normal plane at the beginning.  When it want to go too much left, just put more of the front portion on the floats into the water.  It will track straight.  No need to have a higher angle than a normal plane anyway.  The idea is to keep the water away from the prop.  Not having it pointing into the sky.  Flaps removes pulling power from the prop, and pulling the nose 30 degrees toward the sky also remove a lot of pulling power.

Have fun

louis

JamesCaird

Re: Which floats?
« Reply #5 on: October 09, 2018, 08:24:23 AM »
Thanks once again, Louis-  my process has been to start with nose pointed 30 degrees to right of desired takeoff heading, 3/4 flaps.  With elevator full back I come in gradually with power to get it moving and right full rudder. Not much rudder effect when slow, of course.  I also found that the water rudders were limiting the right rudder travel before the airplane rudder was at its stop.  Anyway, power in and keep the nose up out of spray.  The turbine is this H800 put the prop about 2 feet further forward than GO 480 in a H295.  As the nose pitches up you get a very strong left turning P-factor which eases off as the nose comes down on the step.  I accelerate into the high 30s and rotate.  Best to lift one float and then the other, you can feel the exceleration as they become unstuck.  On a good half load condition I am off in 20 seconds.
Maybe Michael Steel or Andrew Stolts can add to this.  Andrew was on amphibs.

Will be home in a few days to try the new idea/  Cheers/  Bob Wallace

Louis

Re: Which floats?
« Reply #6 on: October 09, 2018, 09:42:00 PM »
I was doing that on the pilatus.  Now i simply aim at the right direction and don't put the nose so high.  So that i am not turning left on my heels when the P-Factor plus the wind want to turn me left.  Having part of the front of the floats to keep me aligned.  Now i don't need anymore to start 30 degrees off.  Which, for unexplained reason, i don't like. 

Also I have a beta position on the power level.  I found that when landing, pulling the power level backward when the front portion of the floats are still out of the water is not good.  Like a wheelbarrow, putting some resistance so far away in front of the center of gravity was turning me on left or right for a second or two.  Going sideways on floats is a no-go.  Now i wait that the front portion of the floats is in the water before pulling all the way to beta.

Also ( again ) the turbine is fantastic to approach a dock with the reverse prop.  I can take all my time to park like if i had a car.  Going backward and front to go sideways. Using the water rudders like in a boat.  But the first time i did stop the engine, with the prop at zero thrust position, a sudden surge of pulling came when i stopped the engine as usual (pulling the prop lever at the same time as cutting the fuel).  Now i don't touch the prop lever when killing the engine.  And the prop does not go to some pulling.  It just sit at no-pull position.  After a couple of hours, it does change the angle of the blade to pulling position although.  I think the Caravan pilots do that way.  But they have a mechanism to lock the angle of the blade without any oil pressure.

With that technique to stop the engine, i am ready to park behind my wife surpercub. But for some unknown reason, i still don't do it !  May be just a survival reflex.

Louis
« Last Edit: October 10, 2018, 07:07:01 AM by Louis »