discussion Salto H101, 2.4mtr Baudis

[Guest]

Hi, I have just flown the Baudis 2.4 metre Salto for the first time and have struggled somewhat in trying to find out the correct C of G and control surface throws, the model is superbly finished yet comes with no build details except a tiny diagram showing a rather suspicious C of G.

My first flight incorporated a spectacular and entertaining tip stall, landings are also quite exciting with the model screaming past with no sign of slowing down until sat out of lift behind the ridge. The glider flys nicely now, after adjusting C of G and reducing elevator throws. It looks fantastic in the air, but it won't stop going up and zooms around like a nutter when you try to keep it down, not that I'm complaining.

If any of you have any advice on setup please share your experience with me.

I took photos of each stage of the installation should anyone else need a hand.

 

[wonwinglo]

A slippery machine.

Salto (2,4m)

4,5MB (5 min

ungeschnittenes Rohmaterial)

Well looking at the Salto it just says 'Speed' with a capital S !

You do not actually say where the C of G is presently located or what it says on the drawing ? also which aerofoil section are they using ? this model really needs spoilers to slow her down for landing something that the model version does not appear to have incorporated,just like the full size she is a slippery sailplane and will emulate the characteristics in model form.

If you can supply me with a few details then I can do some calculations,if you can scan me the full sized aerofoil section used on the model or provide a scaled down one,measure the present distance from the leading edge of your C of G,give me the dimension from wing trailing edge to leading edge of the V-Tailplane,chord of the tail LE to TE,distance from leading edge of wing to nose,give me the models all up flying weight,also the wing incidence angle is important,but this will be difficult for you to measure without the use of a wing incidence jig.

The tip stall on high aspect ratio glider wings is common especially when out of trim,the only way to cure this fully would have been to incorporate some washout into the wing at build,what this does is enable the root to stall first,and not the inevitable wingtips.

It may still be possible to tame her down.

 

[Guest]

 

[Guest]

Thanks for your help it’s really appreciated.

The dimensions are:

Nose tip to leading edge at root 285mm

Wing chord 170mm

Trailing edge of wing to leading edge of V tail base 490mm

V tail chord at base 123mm

Wing span 2455mm

All up flying weight 600grams

Suggested C of G by manufacturer 40mm from leading edge

My C of G 58mm

 

[wonwinglo]

***Jon,still no joy even pasting the links into browser,try this-Go to the pictures and right click 'copy' then return her and paste directly into the message box,that should work,give it a try,make sure that they are jpeg format.

Trouble with my links to images, they do work but not from here please paste into your browser

 

[Guest]

Just to add that since the tip stall I have set the ailerons both up by 1mm in an attempt to create a washout effect.

I think I have this link thing sussed now.

Thanks, Jon

 

[wonwinglo]

***Just what I was going to suggest that you do,it should help smooth things out a bit,try and get the aerofoil shape to me as I want to explain something for you.

Just to add that since the tip stall I have set the ailerons both up by 1mm in an attempt to create a washout effect.I think I have this link thing sussed now.

Thanks, Jon

 

[Guest]

Barry you never cease to amaze me !!!!!!!!!!!! you are indeed the master

 

[wonwinglo]

Jon,just noticed the aerofoil photograph above,as suspected the c of g as suggested by the manufacturer is too far forward,impossible in fact ! lets look at the evidence,bi-symetrical sections generally have aft centre of pressure,the c of p is linked and governs the centre of gravity range which in this case I estimate at 70 mm from the wing leading edge,this gives a latitude of 10 mm either side,which works out about where you have your present c of g.

There are a lot of other factors far too complicated to go into here but it looks as if you have it about right.

Coupled with the essential reflex at the tips you should find that she will fly much better.

 

[Guest]

That's what I thought as well.

 

[Guest]

lol Richard !! "We are indeed not worthy"

 

[Guest]

If I ever knew a fraction about ships as Barry does about Aircraft I would be a very clever man!