Chilli Breeze 48" Build (IC)

[EarlyBird]

Are these the files?

 

chilli breeze rib outlines rev1.pdf

 

chilli breeze wing rev1.pdf

 

or are there others?

 

Steve

[Jeffrey Cottrell 2]

Hi Early Bird

Yes, those the ones for the Breeze. I also have copies of the original build article if that helps. Also same for the Wind. Can send any or all, let me know.

Jeff

[kc]

 

 

 

 

 

 

 

The fact that more than one person reported tailplane failure while the tailplane is of very normal ( 1/4 balsa) construction suggests to me that fuselage itself might be the problem.    It is quite narrow, so perhaps increasing the width at the tailplane seating might be worthwhile.   Adding an amount  to each of the rear fuselage formers might achieve this.  Perhaps 1/4 inch added to the vertical centre line of each former might work and still have the correct taper.  This would give an added 1/4 inch to the tailplane seat.    Or a triangular balsa fillet each side under the tailplane might do the same but wouldn't stiffen the fuselage as much.

Of course it might have been elevator flutter which caused the problem, so maybe consider extending the tailplane tips back to 'enclose' the elevator might be a good idea.  Obviously ensure linkages are well made and make sure the engine bulkhead is very firm.

[Andy Stephenson]

Control surface flutter is very noticeable as a loud rubber band type twang noise heard well above any engine noise. I have experienced this a few times. In my case there was none of that, one side just suddenly tore off.

[Nigel R]

plan and article on OZ now:

 

https://outerzone.co.uk/search/results.asp?keyword=chilli

[kc]

The Chilli Breeze plan shows that it has a very conventional tail end which gives no clue as to why the tailplane broke for some people.    One non conventional thing is it's rather narrow- look at F7.   It also has a vertical grain doubler too but that shouldn't cause any problem should it?    The elevator tips are exposed and sharply angled which might be worth changing slightly.

Fitting powerful engines in small lightly built models sometimes causes problems if used for long periods at full speed - quite a few funfly models have a warning about this.

 

Note that the larger version -Chilli Wind- has a foam veneered tailplane of thicker section.

 

 

[Jeffrey Cottrell 2]

Hi Early Bird

Yes, those the ones for the Breeze. I also have copies of the original build article if that helps. Also same for the Wind. Can send any or all, let me know.

Jeff

[Piers Bowlan]

 A while back I bought a second hand (May 91) edition of RCM&E which featured the Chilli Wind. It looks fast standing still! Mine will be electric, once I have finished my current build. ?

[Delks]

On 22/05/2022 at 09:39, kc said:

 

 

 

 

 

 

 

The fact that more than one person reported tailplane failure while the tailplane is of very normal ( 1/4 balsa) construction suggests to me that fuselage itself might be the problem.    It is quite narrow, so perhaps increasing the width at the tailplane seating might be worthwhile.   Adding an amount  to each of the rear fuselage formers might achieve this.  Perhaps 1/4 inch added to the vertical centre line of each former might work and still have the correct taper.  This would give an added 1/4 inch to the tailplane seat.    Or a triangular balsa fillet each side under the tailplane might do the same but wouldn't stiffen the fuselage as much.

Of course it might have been elevator flutter which caused the problem, so maybe consider extending the tailplane tips back to 'enclose' the elevator might be a good idea.  Obviously ensure linkages are well made and make sure the engine bulkhead is very firm.

 

The tailplane failures mentioned sound very much like victims of the dreaded elevator flutter. The Chilli Breeze has been popular over the years and people have sent me photos of their models fitted with ic engines ranging from a Magnum GP 25 up to an Irvine 40  (even a piped 40) and they have not reported this issue. It would appear that one of the main causes of elevator flutter is that the connection between the control surface and the servo isn't slop free. The the servo must be securely mounted in the fuz - metal gears are preferred to plastic - make sure there is no play at all in the connection between the servo output arm and the pushrod end and the other pushrod end to the control horn - the push rod should be a straight run with no bends at all along its length. Choose a firm medium grade sheet of balsa for the stab and forget about weight saving as you will most likely have to add weight to the tail if you choose a light grade balsa and you will also be building in a potential problem.  I used a built-up tail for the prototype of the new EP version and that had surprisingly good torsional rigidity - you will see on the attached photo that I have avoided all end grain joints around the centre in an attempt to build in max strength and so far so good.....