Shape of Nieuport bellcrank?

abufletcher · 29 May 2005, 08:34 AM

Can anyone provide any insight as to why the aileron bellcrank on the Nieuport is shaped the way it is? My own guess is that it needs to straddle the rear spar.

abufletcher · 29 May 2005, 12:25 PM

Another thought may be that it's the curved "arms" on the bellcrack that actually limit the aileron movement. As the control rod attached to the front of the bellcrank was pulled down (by a bar attached to the control column) this would rotate the center-point of the bellcrank forward thus raising the aileron. This travel would be limited by the lower curved part on the part of the bellcrack behind the pivot point (that's the part you'd see on sticking up out of the wing) as this came up against the rear spar which appears to run THROUGH the bellcrank. Likewise as the control column is moved in the opposite direction it would push the rod upward thus rotating the torque rod rearward and lowing the aileron.

This is just an exercise in the logic of design. I don't have any facts to back this up. Unfortunately the Macchi drawings don't show the bellcrank so all I have is the shape in the Nieto drawings to go on.

edmondthieffry · 29 May 2005, 12:59 PM

Hello Abufletcher,

Sadly, I've only a picture of this bellcranck. You can find it here

Hope this is of little help.

Best regards from Belgium.

Philippe

abufletcher · 29 May 2005, 05:36 PM

Philippe, thanks! That's a huge help. Your photo confirms that the spar runs through the middle andshows the thickness of the arms. Also I hadn't realized it was constructed of two parts. I had been wonder how they got it around the spar!

abufletcher · 29 May 2005, 11:42 PM

I somehow just can't make sense of how this thing worked! In this drawing the front end is attached to the control rod and te rear looks like it would be in the position to connect with the aileron torque tube. But this just doesn't make sense. The only way to have the up and down movement of the control rod be translated into rotational motion would be to have the aileron torque tube connecting at the pivot point.

I'm not very mechanical so maybe someone else can offer an understanding.

mossie · 30 May 2005, 12:01 AM

The bellcranks pivot is the aft aileron tube behind the rear spar. The curved sections are just to clear the spar. The aileron pushrod from the cockpit connects to the forward extreme end of the bellcrank. The vertical cross tube is for strengthening.

I'm not aware of it being two parts, more likely that the aft section is split with the bolts being used to clamp onto the aileron tube. This would be critical to operations as it acts both as pivot and transmits all the forces between aileron and control stick.

abufletcher · 30 May 2005, 12:40 AM

OK. NOW I get it! The forward holes on the diagram are just lightening holes and the whole thing pivots around the aileron tube. Seems so obvious now!

I can imagine this being a two part assembly since otherwise they would have to build it in place when the wing is assembled.

1 June 2005, 12:17 AM

Hi Abufletcher,
I have looked throught the Nieuport drawings that I own, and I do have a copy of the original French factory drawing for the Aileron Bellcrank. It is drawing number 24465. (This is for the 23 / 24 / 27 series.)

I am currently scanning all of the drwaings so that I can create CD-ROMs containing all of the drawings, if you PM me with your address, I will send you a paper copy of this drawing.

Regards,

Robert.

1 June 2005, 01:40 PM

This is a digital picture of 24465, "Levier de commande des ailerons" reduced to meet the image size restrictions. I will email high resolution pictures of views shown on the drawing to you. The aft section is a separate piece, part no. 24467, part name "Equerre." It appears that the main body forms a clamshell around the "Equerre", which features 15mm lightening holes on the portion inside the clamshell.