Ok I have moved on from the high wing trainer to my low wing trainer....

Its a Phoenix Dolphin 40...


I'm finding, however that it is extremely "floaty" and "slippy" (Ie very good glide rate and its fast!) and i'm having a hell of a job getting it down.

The manual/stock setup is one standard servo for ailerons.. i've just upgraded it to twin mini, metal geared servos for the wings so I can add spoilerons...

I've read that flapperons on full length ailerons is a bad idea as it can induce a tip stall .....


Roughly what percentage of the aileron throws would be a good starting place... and rough "nose down" to mix in when spoilerons are raised?

(I understand completely it would need to be rough guesses but i've no idea where to start!!)

Ta

I had the Phoenix Dolphin for my second plane. I'm wondering if your CG is too far forward. That plane flies just like a trainer, maybe a touch faster but nothing you shouldn't get used to in a day or two. You should be able to bring that plane in pretty slow.

The trick to slowing down a landing approach is the proper CG. You should be able to use your elevator to push the tail down into a slight nose-up attitude to slow down, using your throttle to adjust descent rate/glide slope. Nose down to pick up speed, nose up to bleed off speed.

I personally wouldn't mess with spoilerons on that plane, but that's just me.

What engine and prop are you using?

While Flaperons are a bad idea, spoilerons are an even worse idea. The purpose of a spoiler on a wing is to kill any lift the wing produces (not slow the plane down). Glider pilots use spoilers to kill the lift on the wing when the are trying to spot land their gliders in a target circle. When you deploy a spoiler it disrupts the flow of air over the top of the wing so that the wing can no longer produce any lift. If you deploy a spoiler, or spoileron, at a slow speed on approach for landing you are going to stall the plane in a position where you have no room or speed to reestablish lift on the wing and start flying again, which is going cause a crash.

The problem you are having being "floaty" and "slippy" is nothing more than you need to learn how to slow the plane down, but trust me in that this plane will slow down and fly at a reasonably slow speed. Just like anything else in flying, you need to learn how to do it and learn to be comfortable doing it. The best advice I can give you is to fly the plane at a couple of mistakes high and practice slowing the plane down until you find the stall speed of the plane, and then practice flying slowly without stalling it.

Hope this helps

Ken</p>

This is poor advice to give for a landing approach. You should use your elevator to keep the plane level, or slightly nose up, on the approach. And then use the elevator to flair the plane out just before it touches down. Flairing the plane out should stall the plane so that it quits flying and touches down with no more lift. While on the approach the speed should be controlled with the throttle. Also, the amount of lift is also controlled with the throttle. When holding the elevator in a level attitude applying the throttle will slow the rate of decent and lowering the throttle will cause the plane to come down faster.

While the first part of Garfields advice is the same as mine, using the elevator to control the attitudue, the second part could lead to some real problems. Following the above advice is not recommending as if you nose down you could put the plane into a poor attitude that may not be able to be recovered from and causing a crash. And raising the nose could cause the plane to stall out at a low altitude that you may not be able to recover from causing a crash.The elevator should be held pretty much at a constant during a normal landing approach, and the throttle should be used for your adjustments.

While the CGdoes affect how the plane slows down, it's not "the trick". Learning to slow the plane down and fly at slower speeds is going to be the same regardless of where the CGis located. The issue here is more about learning how to properly fly the plane, and less about how the plane is set up. As you are still learning to fly this plane your best bet is to put the CG right in the middle of recommended range and learn to control the plane with it set there. Once you are comfortable flying the plane, and can slow it down properly, then you can start experimenting by moving the CG and seeing how it affects the flight of the plane.

Ken

Its got an Os55 ax and a (i think I recall correctly ) 11x6 prop.

I'm completely confident with the plane..
I've been flying it over a year now and Its my 2nd nitro plane after 5 years with 60" racing gliders.

What i'm finding is that It just floats and floats and floats...

When I come into a landing.. no matter how early I cut the throttle. stick RIGHT down.. in the down wind leg.. I always just end up floating along the runway and having to go around.
I never get what i'd call a decent "glide slope" out of the plane..

It feels like passes from horrizontally floating at "high speed" (with respect to landing) to stall.. with nothing between.

For our club I NEED a steep angle of approach... we have a small plot of land with orange trees on all sides.. so I CANT glide along low for a long time.. I have to come in from relatively high..
SO when I come in at the height thats needed not to hit orange trees.. I then have to duck down to land.. and at that moment it accelerates and becomes floaty again.

I would try a 12x6 prop. You will idle slower. 11x6 is pretty light for that engine and it's probably spinning a bit fast for landing.

Luckily I have a 12x6 here!

I am just checking CofG.
It is ballencing at the manual's stated 3.5" (8.9cm) but with a slight nose down attitude...
So i'll also work to make it more level....


Just noticed current prop is 11x7..
CofG, I've also retested....

I had a flight nose down angle at the c/g on the jig.. so I started moving the plane back on the jig to see what distance there as between the plane balancing level and the marker for the LE..
Well it turned out to be well over 1cm.. not quite 2cm's
manuals sated Margin for c/g is 1cm......

These 2 things might just fix this problem!
Now if only I had some fuel left ot test tomorrow

I flew my Dolphin with a 46AX and an 11x5, then a 12x5. I think you are going to be in for a treat. Let us know how it works out.

... come to think of it....
The c/g problem would explain why I cant (and not for the lack of trying) get the damn thing to do a flap spin... they are always more of a vertical cork-screw..

If you want to slow the plane down, go to an APC12 1/4 x 3 3/4 prop. It's going to cut your top end down some, and if you don't watch it, it will let you over rev your engine, but when you cut the throttle, it is like stepping on the brakes. You have to adjust your engine so it will idle reiabaily at 2200 rpm and still answer the call for a go around, but that prop will put on the brakes like no other.

After hitting the road across the end of our runway, and cliping the fence once, I usually come in high and at full idle and that prop will let me land about 1/2 way down our 500 ft runway with no head wind. With a slight head wind, I've got to watch that I don't set down to soon.

Don

First impressions are that the problems solved!
Its difficult to really tell though as today has a 30mph wind with wild gusts... so either way everything will "slow down" on an upwind leg..
Normally here there isnt even a sheeps fart's worth of wind...
However the plane definately had a better glide slope and seemed to have less intention to retain its height and there was far better deceleration.
This I prooved by taking a long glide along the "runway" (we dont have one yet) at about 1ft height with 10% power... killed the power and it touched down fine.... Earlier it would just carry on untill it stalled... and i've have to actually nose down... not fun.

Ta muchly all