Aileron differential all up & NO down?

[martin collins 1]

Sorting out a Flair Puppetter i bought recently which has a centre servo and bellcranks which give only up and no down, plenty of up movement, would it fly ok like this, i can obviously mix rudder if needed to help. Obvious mod is to take the centre servo out and put new ones in the wings but to save all the work as i have a number of models that require sorting over the winter would it fly ok set up as it is?

[Don Fry]

1 hour ago, martin collins 1 said:

Sorting out a Flair Puppetter i bought recently which has a centre servo and bellcranks which give only up and no down, plenty of up movement, would it fly ok like this, i can obviously mix rudder if needed to help. Obvious mod is to take the centre servo out and put new ones in the wings but to save all the work as i have a number of models that require sorting over the winter would it fly ok set up as it is?

Method of avoiding adverse yaw on biplanes SO THE PILOT CAN BANK AND YANK, NO RUDDER NEEDED. 
It will fly fine, as long as you can refrain from auto use of rudder in a turn. Otherwise, you have to learn a new skill.

[John Wagg]

Will it fly like this ? Well I wouldn't. 😉

You don't need 2 servos. Just a different servo "disc" or alter the angle of the aileron horns,

Sussex Model centre says :-

Centre of Gravity Position. is 130 mm back from top wing leading edge.
Control Throws = 
Elevator 20 mm up and down
Rudder 35 mm either way
Ailerons 15 mm up, less down according to differential, try for about 8 mm"

https://sussex-model-centre.co.uk/products/flair-puppeteer-mk-ii-kit?srsltid=AfmBOooEpmh4fyuaoFXBQHBXmJfElXfbwBcpW7Mgm0TrJi0fSjYdecMa

 

 

[John Wagg]

Thinking about this again - how do you get NO down. 

If there is no down then I would suspect a problem.

What linkage setup is there ?

 

Edited November 29, 2024 by John Wagg

[Jon H]

I was taught to fly by my dad using a flair pup. Its still more or less airworthy but you will need some down aileron on yours to make it happen. I cant work out how its previous owner as managed to mess up the geometry that badly. 

 

No matter what you do with a WWI fighter it will always be a WWI fighter and it will not fly like for favourite F3A job. I dont really know why people try and make all of their models fly exactly the same as i rather enjoy the nuances of each different model. 

 

In any event i would suggest you fix the ailerons to give a more normal approach but dont bother mixing the rudder on the tx, do it manually. You have 2 hands, 2 sticks, and an infinitely programmable computer in your head which can improvise and adapt far better than your tx can. You can also cant do cross control stuff (aileron and rudder in opposite directions) very easily if you mix them on the tx. 

 

I would also like to point out that many people over power these models as they are very draggy and need masses of power fly fly at 'normal' speed. Normal being relative to a wot 4 or even a 46 equipped trainer. The point is, they shouldnt fly that fast. With a gentle headwind they should waft in just over walking pace and will fly very nicely at half throttle on 50 4 stroke (or equivalent) levels of power. 

 

I have a flair pup in a sorry state of repair which i do intend to fix up as soon as i can. It will be getting a 50 class 4 stroke of some kind, most likely an old OS52 i picked up cheap with crash damage. 13x5 prop (maybe more) and it will be lovely. 

[J D 8 - Moderator]

My Major Mannock has one center servo and is still set up as by original builder with similar movement up and down. When I first flew it some twenty seven years ago I was some what surprised that a full stick of aileron did little to initiate a turn it just kept going on ahead leaning over and wallowing around when elevator was put in some. I soon learned a good dose of rudder was needed to initiate a turn, In fact it will fly just as well using just rudder elevator. It is what it is a semi scale WW1 aircraft. I have not changed anything and enjoy flying it quirks and all.

[Don Fry]

1 hour ago, J D 8 - Moderator said:

My Major Mannock has one center servo and is still set up as by original builder with similar movement up and down. When I first flew it some twenty seven years ago I was some what surprised that a full stick of aileron did little to initiate a turn it just kept going on ahead leaning over and wallowing around when elevator was put in some. I soon learned a good dose of rudder was needed to initiate a turn, In fact it will fly just as well using just rudder elevator. It is what it is a semi scale WW1 aircraft. I have not changed anything and enjoy flying it quirks and all.

I think that is wot they did in 1917.

 

nice photo, what is that mist? On the grass, marsh, wood transition.

 

 But back to post. Bloke asked will it fly, can you control it. The answer is yes. 
What is the BEST, go down the museum, ask the bloke nicely, wagle the stick, so I can measure deflection. Or ask nicely how it’s set up. Not necessarily right I hear, but it’s scale. 

[Frank Skilbeck]

Full size Tiger Moth has 10deg up and 1.5deg down.

 

Will yours fly, then yes, I fly gliders and with the ailerons raised for landing I still have roll control, and in this mode full aileron might be +5 one side and +30 deg on the other.

[J D 8 - Moderator]

Hi Don, Yes as with most aircraft of the early years of aviation rudder is the primary steering control.

   Photo taken at our strip a former WW 2 airfield. The "mist" beyond the old concrete runway and next to the woods is an area of tussock grass. Pic was taken in the Autumn and the seeding stems of the tussock are dying off.  A good spot to crash, my Citabria was saved by it when I lost control of it recently.

[Christopher Wolfe]

When I flew 1/2A pylon racers (0.49's) many years ago I discovered that one aileron (on the starboard wing) was most satisfactory to bank

left and keep the nose up during the 'bank and yank' high speed turns. No rudder servo was installed or required.

 

This greatly simplified servo installation and reduced drag.

 

A few races were won with this 'bank and yank' technique.

 

Engine shutoff was by using a fixed pickup in the tank and rolling inverted.

 

* Chris *

[Simon Chaddock]

I am a bit concerned at the comparison to original WW1 panes. Most RC models are aerodynamically quite a bit different. Just look at the wing sections used.

The only issue with all up and no down is the amount of yaw caused when full aileron is applied. Excessive yaw in turn will cause the nose to drop which can be a problem with a panic aileron input if low and slow. 😉

As a regular "bank and yank" flyer using aileron differential I can only add that as with any control surface set up It is important to understand what is the cause of what is happening and recognise it may take some trial and error adjustment to arrive at flight characteristics that you are happy with.

[Doug Moss]

For what it's worth, my Pietenplank is set up in flaperon mode. All down and no up is predictably unpleasant, all up and no down just results in a reduced roll rate.

[martin collins 1]

Thought i would give you an update on this, the lack of down movement was due to the small wheel type servo arm and the rods from that to the bell cranks seriously binding. The servo was fitted in such a way that the only way to get the small wheel off the servo and free up the rods was to cut the plastic ends off the rods at the servo end so the servo could be removed. Having got that far i decided to strip the rods/bellcranks out and fit a pair of servos, one for each aileron. Model was test flown this afternoon and performed as expected from a Puppeteer.

[Konrad]

Have you guys thought of using a threaded shaft into the servo arm. I do this a lot when I need a servo arm less than 5mm. Here I'm showing how it is done with a 4mm arm. Note that any need for the push rod to go past the servo output shaft is addressed by having the push rod pass over the arm/output shaft. The threads are the retention feature. This works real well with metal arms.

 

(This is shown for a glider I was setting up. But I hope you all get the idea.)

Edited December 4, 2024 by Konrad