I-153 main gear question for tech savvies here

[McHilt]

Hi,

I was studying the main gear of the I-153 recently to find out what causes the rotation of the strut during retraction in the wheel-well. It looks quite obvious but somehow I can't figure what actually causes the rotation in this case.

the picture shown below is a kinematic representation of the main gear of the Chaika:


Any of you have any clue or insight?...
thanks

Here's another pic:

[Kodoss]

As you can see on your first picture there's the main strut[olive] with the shock damper and the wheel on it connected with a 2-axes hinge. With that connection you could turn the wheel in every direction around the 2 axes. Also the angle of the hinge is not in the same angle as your wheel.

And here comes the hollow shaft[green] with the 2 supportive struts[light blue] in action. Those struts force the main strut to move in a certain direction, which results in a movement of both axes of the hinge. By that movement the main strut[in the picture] will be turned up and clockwise around itself.

[McHilt]

Kodoss,
if I get you right you say the main strut is connected to the frame by a double hinge (something like a drive shaft coupling)? That makes sense.
Been looking for pictures of the strut connected to the fuselage but never found any that gives away the actual hinge. Interesting.

Thanks a bunch for the reply

[AdamB]

basically the support struts that are attached to the main do not and cannt bend, this means they cause the wheel to pivot, (around the pivot point at the top of the main wheel structure, ref. the 1st pick) this then causes the wheel to turn whilst it is going into the landing gear up position

[Sternjaeger II]

I don't know whether that drawing is accurate or not and I'm not an expert on the Chaika, but normally that kind of rotation for a component that needs structural stiffness is done by means of cog and rack, like in the P-40 (the cog and rack are black and barely visible on this pic).

[McHilt]

Thanks for the replies folks...

Sternjaeger,
The chaika doesn't have such a cog-rack construction. I don't know how it works on the chaika but Kodoss's his suggestion makes sense and matches with the pictures I have of the gear. Anyway, good picture of a basically very simple solution to rotate the main strut on the P-40.

Here's another great picture (although it doesn't show the hinge (left) clearly):


and also a clear picture of the construction as used on the P-40:

[Sternjaeger II]

yup, I think it's all in the angle of the hinges as Kodoss suggests. Probably not the more robust design ever, but considering the weight of the Chaika, it surely does the job in a nifty and effective way. Was it operated by a hand crank like in the I-16?

[WTE_Galway]

Originally Posted by Sternjaeger II

yup, I think it's all in the angle of the hinges as Kodoss suggests. Probably not the more robust design ever, but considering the weight of the Chaika, it surely does the job in a nifty and effective way. Was it operated by a hand crank like in the I-16?

Wiki claims it was manual but the Pacific WINGS Magazine article quoted below (by Tom Middleton from New Zealand Fighter Pilots Museum) claims it was pneumatic. I am inclined to believe Middleton. If nothing else, how on earth would they get a crank into that miniscule cockpit.

http://akawardogs.net/AKAforum/index.php?topic=1606.0

Take-off is exciting with plenty of right foot required against the torque and slipstream at maximum power and with such poor visibility behind the big round nose it feels like charging along a runway behind a block of flats. The engine noise is very loud even with earplugs, the tail must be helped up to the climbing attitude and the Chaika must be kept straight.

Lift-off occurs at about 110 kph and instead of winding the undercarriage up as with the I-16 this undercarriage is raised pneumatically with a small lever near the left knee. As with the Yak-3, activation is accompanied by a very loud hissing noise clearly heard over the engine at full power.

[McHilt]

Iirc in Il-2 it was manually operated (don't know if one can consider that the most reliable source though), however an airshow movie on YT shows a chaika taking off... you can see the gear retracting very quickly which might suggest it was indeed operated pneumatically (if the bird is restored in original configuration that is).

http://www.youtube.com/watch?v=4BLVI2yBRX8

btw you gotta love the sound of that radial engine

[brando]

No Mac, in IL-2 the Chaika gear comes up with a single 'key-press' - it's the Rata that has the manual gear.