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My first Yak

I really like this quote from wiki.. "The resulting design, the Yakovlev Yak-55, was a single-engined all-metal cantilever monoplane. The aircraft's wing is mounted midway up the fuselage and is of thick, symmetrical section to aid inverted flight"
SHIPCHIEF
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My first Yak

Post by SHIPCHIEF » Sun Feb 05, 2017 9:44 pm

I flew IAC Primary last year in my RV-8. Catto fixed pitch, fuel injection, no inverted systems.
My son Peter has been steadily working his way up and has passed thru a few planes. It's been a good experience.
As any of you who compete in IAC know, competitors must also judge and assist, as well as any other official capacity or contests can't happen.
So I got to watch all manner of aircraft, how they perform and how they "present".
Last Friday, I committed to buy a Yak55m. I hope it will be a good fit.
I don't find a lot of Yak55 info on the web, somewhat more on the M14p. Any leads for this info is most welcome and would make good topics for the "Russian" thread.

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Re: My first Yak

Post by Anthony-NYC » Tue Feb 07, 2017 9:15 pm

Congrats on the Yak! A very cool airplane indeed. I am still dreaming at this point.


https://www.youtube.com/watch?v=HrauVqfNWq8

SHIPCHIEF
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Re: My first Yak

Post by SHIPCHIEF » Tue Feb 28, 2017 10:36 pm

I did buy the Yak-55M.
The weather was in the 30's F, and the plane hasn't flown in more that 6 months. My son and I pulled the cowl, and opened the intake drains + pulled all the front spark plugs. A lot of oil came out of one of the cylinders, especially when I cautiously started the pull the prop thru a few blades. This is not abnormal.
The air tank was holding about 600 psi, but the battery voltage was too low, about 14V instead of 24v. I got to learn about Russian 24V battery cases and 12V 5Ah AGM Wheelchair batteries. These have spade (faston) connectors and 2 batteries fit in each case, wired in series. The 2 battery cases are wired in parallel. These cases are some kind of green composite, with about 12 drilled head screws (for safety wire!) holding the top on (which has a folding lunch box type handle) The battery cases are held in place by a bar mount held by 3 big T bolts and equally robust wing nuts that are also safety wired.
The whole battery assembly is connected electrically by a pair of pin plugs held in place by snap springs. One of the plugs had broken at the split tip and had a local solder blob repair that required a piece of packing to side load it so it wold make contact.
These cases we took apart, to find one (of the four!) wheel chair batteries had failed low. also, the spade connectors started to fail, 2 required repair and the rest very careful handling. A "used but good" battery finally netted us 16 volts after re-assembly....short of the 19v minimum requirement listed in the manual.
Bummer. The engine would barely turn over in the cold weather, and we only got a few pops on one or two cylinders. We recharged the air start tank from a SCUBA tank and tried to start it a few times. The seller was very helpful and enthusiastic, but we didn't get it running.
Then I ran out of time and had to go to work.
I'm removing the Russian battery cases and pin plugs. I have a pair of Lithium Iron Powersport batteries on order. These are locally accessible, and will save about 10 pounds. Also a great number of excess electrical connections will be eliminated.
There is quite a bit of weight savings potential available under the cowl...

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Re: My first Yak

Post by MonoPlaneForum » Wed Mar 01, 2017 11:31 am

Sounds wicked! Would love to see some pics!

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Re: My first Yak

Post by SHIPCHIEF » Wed Mar 01, 2017 10:17 pm

Here is a pic from the past:
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SHIPCHIEF
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Re: My first Yak

Post by SHIPCHIEF » Fri Mar 03, 2017 1:17 am

The Lithium Iron batteries fit right in. They weigh 1.75 pounds each !
I re-terminated the wires and connected them to the battery, a perfect 25 volts.
After the usual spark plug and intake drain opening, I attempted a start with about 2/3 of an air charge. I got a few promising pops, but that was all, then I was out of air.
We searched for SCUBA shops. After supper, a rented SCUBA bottle revealed air leaks in my connecting hose/hardware, a broken O ring. I probably flooded the engine during a few more attempts, and gave up in the rain and darkness.
I'll repair the tank adapter and return tomorrow. This time I might check the "Shower of Sparks" with all the left mag plugs out before the next start attempt.
When I watch the air start procedure on Youtube, it looks so easy... https://www.youtube.com/watch?v=Om7ZxEXyTew engine start @ 2:50.

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Re: My first Yak

Post by MonoPlaneForum » Sun Mar 05, 2017 3:58 pm

SHIPCHIEF wrote:
Fri Mar 03, 2017 1:17 am
The Lithium Iron batteries fit right in. They weigh 1.75 pounds each !
I re-terminated the wires and connected them to the battery, a perfect 25 volts.
After the usual spark plug and intake drain opening, I attempted a start with about 2/3 of an air charge. I got a few promising pops, but that was all, then I was out of air.
We searched for SCUBA shops. After supper, a rented SCUBA bottle revealed air leaks in my connecting hose/hardware, a broken O ring. I probably flooded the engine during a few more attempts, and gave up in the rain and darkness.
I'll repair the tank adapter and return tomorrow. This time I might check the "Shower of Sparks" with all the left mag plugs out before the next start attempt.
When I watch the air start procedure on Youtube, it looks so easy... https://www.youtube.com/watch?v=Om7ZxEXyTew engine start @ 2:50.
awesome vid, thank you..

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Re: My first Yak

Post by SHIPCHIEF » Mon Mar 06, 2017 1:06 am

The next day I returned to the hangar and installed 9 new spark plugs across the bottom cylinders while going thru the draining process.
I placed the SCUBA cylinder in the cockpit so I could monitor the start air reservoir easily while refilling and because I no longer had confidence the engine would quickly start. I pushed the Yak out of the hangar with the cowl off.
The SCUBA tank adapter is actually a first stage SCUBA regulator, with the hose connected to an unregulated port. The base O ring was replaced, but the regulator piston also leaked. I removed the spring for a slight improvement. At this point I was expecting the SCUBA bottle to run low, considering the severity and number of leaks in the adapter set up, but I did get the engine started on the last wheeze from it. Marilyn my wife disconnected the adapter fitting from the fuselage and I handed the SCUBA bottle down to her.
I taxied about the airport, getting familiar with the plane and engine and watching for the air reservoir to build. Eventually I did get the un-loader lever to work and an acceptable charge was attained.
The massive pulling power of the engine and propeller could easily overcome the Cleveland brake upgrade, my leg muscles weer quivering when I was done for the day.
Next up: fix the air unloader valve control, Install the cowl, and fill the fuel tanks. I think it is ready for a flight, but my ability to reliably start the engine is in doubt. This takes some practice. I would hate to wait several minutes for the air pressure to build after taxiing to the fuel dock, then after fueling, not be able to start, and running down the air.

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Re: My first Yak

Post by N23LZ » Mon Mar 06, 2017 9:52 am

Every girlfriend has their quirks. I'm sure you will soon have them figured out!

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Re: My first Yak

Post by MonoPlaneForum » Mon Mar 06, 2017 10:27 am

Right on, sounds like an adventure... A fun one..

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