ЗУБ markings in I-16 cockpit

[FTC_Frederf]

  It appears the ЗЧБ markings in I-16 cockpit are some kind of range or angle estimating device.

What I don't understand is:

What ЗЧБ means.

What is symbol between 1 or 2 or 3 and ЗЧБ. Apostrophe? Caret? Degree?

 

How are markings to be used? If layout is

1^ЗЧБ | 2^ЗЧБ | 3^ЗЧБ |  | 3^ЗЧБ | 2^ЗЧБ | 1^ЗЧБ

Which parings of vertical markings should be used?

Edited March 23, 2018 by ACG_Frederf

[=2ndSS=temkatt]

it's not "3ЧБ" this "ЗУБ", 1 ЗУБ, 2 ЗУБ 3 ЗУБ
In view of the gear teeth

A mechanical pointer, when the landing gear is fully released into the working position, enables the pilot to judge on which tooth of the lock comb the locking of the creeper has occurred. To do this, on the indicator scale on the left and right sides are plotted with the numbering of the teeth of the lock comb.

 

And the symbol is used this "*" acts as a separator between the number and letters

 

I apologize for my English, I use an interpreter.

Edited March 22, 2018 by =2ndSS=temkatt

[FTC_Frederf]

Interesting. I see the 6 cutout shapes above the scale. Yes careless translation, zub "tooth". Why multiple landing gear locking teeth? Are different ones used at different times?

[=2ndSS=temkatt]

 

Landing gear lock. When the landing gear is down and became locked, it should be in 3 positions

1 ЗУБ and 2 ЗУБ position - the landing gear is not locked.

I can not find a photo in good quality, but it can be that the character between 1 and the ЗУБ is a small letter "й", that is, the 1st "ЗУБ" - 1й ЗУБ

Edited March 22, 2018 by =2ndSS=temkatt

[=2ndSS=temkatt]

fixed drawing

 

Edited March 22, 2018 by =2ndSS=temkatt

[FTC_Frederf]

Yes it looks like 1й зуб or 1st tooth. I did not recognize "U" looking letter as й.

 

You may have the tooth markings on the landing gear labeled in reverse. When the 1й зуб marking is reached the latch will engage with the зуб closest to the center of the airplane. It will be the first зуб reached in the process of raising the gear. Cranking the handle more the next зуб is engaged (2й зуб). And lastly as it is in the drawing the 3й зуб is engaged.

 

I was just wondering if it is ever used 1st or 2nd tooth in normal flying or is the gear always retracted to 3rd tooth?

[=2ndSS=temkatt]

Yes, I numbered positions in the drawing in random order, just to show what it is.
There's quite an interesting mechanism, but my English unfortunately does not allow me to correctly describe it. I will give a link to the technical description for Polycarpov I-16. It's in russian, but maybe you'll manage to understand through an interpreter better than I can.
http://www.airpages.ru/po/i16_gear2.shtml

[FTC_Frederf]

Of course I make the mental mistake to think that the tooth and comb are for up lock. At least the marked positions on cockpit scale for tooth are down lock. It is also said that full release is the 3rd tooth. Perhaps the markings for 1st and 2nd tooth are to explain to the pilot why if the mechanism is not responding to motion in case of fault.

 

Lastly it makes sense that tooth and comb are not for direct control over main compressible strut. Geometry near pivoting point does not allow effective holding. It is the secondary rear (trailing) strut which moves its mounting point smoothly laterally inboard which forces the gear fully down. It is similar to an umbrella, pushing the sliding point upward along the spar forces the mechanism deployed. It appears the only item which keeps the wheels retracted is the tension in the cables. But the struts are not subjected to landing forces so it is OK.

[=2ndSS=temkatt]

1 hour ago, ACG_Frederf said:

 Perhaps the markings for 1st and 2nd tooth are to explain to the pilot why if the mechanism is not responding to motion in case of fault.

 

 

Yes exactly