Yak-25M ( twin engine jet ) GPM #546

[Isaac]

The Yak-25M has its main landing gears in the fuselage ( bicycle arrangement ). For ground stability, the aircraft had small outrigger struts with small wheels housed in a canoe type housing in the wing tips.


Here are the parts


assembled



and glued on the wings. ( the opening is on the bottom and will house the struts later on ).



underside view



Isaac

[Isaac]

The landing gear consists of a single nose wheel and a double set of wheels in the back of the fuselage ( there are also small outrigger wheels at the wing tips ).

The laser frames has a set of disks



laminate and glue together. Notice that the center is missing and is to be built separately.



I inserted temporary hubs to allow me to spin the wheels so I can shape on my mini lathe ( you can use any rotating drill device ).



place in the lathe


turn and sand to shape



remove the center temporary hub



Here are all 3 wheels shaped.


nice


Isaac

[Isaac]

At this point, The wheels are painted black rubber color


I added a simplified version of the wheel rims since most of it will not be visible anyhow. It is painted green which is common to all Soviet jets.




Isaac

[Butelczynski]

I find it interesting how so many aircraft were designed with bicycle type of a landing gear in 1950/60s and I can't think of any designed in last 20 years.

At the same time B-52,U-2 and possibly Harriers are still buzzing around

Nice build Issac.I like your wingtip pods-I had hell of a time with mine even with their much simpler design.

[Isaac]

Originally Posted by Butelczynski

I find it interesting how so many aircraft were designed with bicycle type of a landing gear in 1950/60s and I can't think of any designed in last 20 years.

At the same time B-52,U-2 and possibly Harriers are still buzzing around

Nice build Issac.I like your wingtip pods-I had hell of a time with mine even with their much simpler design.

The bicycle landing gear in my opinion is a bad compromise. It trades off a lighter and more flexible wing to a fuselage that loses precious volume to house a landing gear. All that space could be used for fuel and equipment . Also, this design makes the plane wobly on the ground during turns. So handling is poor compared to tricycle gear .


It was a dead end concept. However, if you have a twin fuselage aircraft, then this concept is still usefull, like the new space launcher planes. But those are specialized one off designs.google Stratolaunch aircraft.


Isaac

[JoeMon]

Great job on the tires, model coming along really nicely

[Isaac]

The aft main gear has a single large pivoting arm that retracts aft. The shock absorbing damper is connected on the inside and takes all the landing load.

Since the assembly is mostly buried inside the aft gear bay it will not be visible, so you decide how much detail you want there. The most important thing is that it is structurally strong enough to support the plane.

I added a metal paper clip to support the pivot axle to the wheels axle. Use super glue .



test fit the wheels on.


glue the inner skin on the leg. No worries about the job, it will not be seen when assemble to the plane. Get ready to paint it.


paint the leg grey



here is the leg.



now the strut/damper/ actuator. Again, say goodbye as you will not see it. However, it is a structural part and needs adjustments. It will be removed when the leg is glued on and then inserted and attached to the leg.



Install the leg



and wheels are on.



Isaac

[Isaac]

Here is a set of pictures I took showing the retraction of the rear main gear.

Once loaded, click quickly forward and back to get the sense of it.




Isaac

[solo67]

Nice work Issac

the model looks fantastic.

[Isaac]

Here is the model so far




Isaac