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Nov 02, 2017, 04:59 PM
Nose down, you're gonna stall
rowdyjoe's Avatar

Yak 130 90mm Refurbish

I picked up a good deal on an older version of the 90mm Freewing (i.e. Ready2Fly) Yak 130 and have begun the job of refurbishing it. It's not in bad condition but, it was missing parts that were easily replaced via Motion RC spare parts. It appears to have suffered a bad landing at some point in it's career and was put away with incomplete repairs. The front landing gear strut retaining pin was bent so, I un-bent it, both horizontal stabs were missing along with the right main gear and retract unit. Additionally, most of the gear doors were MIA. There are a couple of blemishes that need some TLC but, the needed parts are on order or on-hand and it's coming together quicker than I expected. However, with the holiday season fast approaching, it probably won't be ready to fly until early next year. It's a good winter project.
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Jan 03, 2018, 05:53 PM
Nose down, you're gonna stall
rowdyjoe's Avatar
More on the Yak 130 ...
First flight was short and not so good. As it turned out, the "zero" position of the elevator was incorrect and the plane acted like it was severely tail heavy. The elevator control system is nothing like I've seen before. It is completely housed inside the aft section of the fuselage and controlled by two servos. It is supposed to be set to the correct position during assembly but, was not. After a near fatal crash on the first flight, I double checked the CG and determined the correct position via the "new version" of the instructions and asking questions on the extensive forum on RC Groups. 60 clicks of down sub-trim came very close to the correct "initial" position.

About 2 weeks later, after relatively minor repairs, flights 2 thru 5 were successful. Flight #2 was a bit shaky as I trimmed it out but, all worked out OK. Duration with a CNHL G+ 6s 5000mah 70c battery was about 2 min. The landing was a bit hot but, uneventful.

Flight #3 was a bit harrowing as the front nose wheel axle backed out and jammed the nose gear doors leaving the front wheel partially protruding. I landed on the mains and held the nose off as long as I could. When the nose dropped, the front gear doors departed but, were easily recovered. While attempting field repair, I found the errant nose wheel axle retaining clip on the bench (go figure ). Due to missing linkage for the small front gear doors, I flew the next flight without them.

Flight #4 was great. A little trim for roll and pitch and she was flying straight and true. I had read that this was an anemic flyer on 6s but, found that not to be true. The prototype of this plane is intended to be Russia's answer to the A10 so, it's not supersonic. They also have a trainer version. IMO ....flight is scale-like and solid and it handles very well at low speeds. Duration for this flight was about 2.5 min and the landing was easy. It will float forever if not slowed properly on final.

Flight #5 was the best. No issues and very solid. Duration was 3 min. 15 sec.. The battery was warm, as it was after all flights, cell voltage was 3.7 range on all cells and IR was 2 across all cells. The landing was a "grease job" in no-wind conditions.

I LIKE the way it flies and can hardly wait for decent weather to fly it again.
Mar 27, 2018, 09:11 PM
Nose down, you're gonna stall
rowdyjoe's Avatar
I recently picked up a 2nd hand Sbach 50cc IMAC bird (89" WS). It is made by Goldwing and has a DLE 55 on the front, Airtronics digital metal gear servos (high torque), and a smoke system. I spent the last couple of days giving it a bath (removed lots of dust) and getting to know it inside and out. During the inspection process, I discovered a mud-daubers nest in the canopy hatch. It scared me half to death when a live one flew out as I lifted the hatch off. :
This plane had been hanging in a large metal garage/work shop for a few months (years?) but, other than dust, it looks good. I installed my receiver in it today and began checking control movement after installing good batteries. I found that all control surfaces needed mechanical trim changes but, they are all correct now.
I checked the CG markings on the wings and verified them with the manual I found on-line. I don't know how this old girl flew with the CG 1.5 inches too far forward. I doubt seriously that it flew aerobatics very well. I also found an old heavy duty battery mounted right up against the firewall. It wasn't attached to anything as it had no leads and it weighed about a pound. I assume it was there just for the weight. It's no wonder they needed so much nose weight with the CG mis-identified. Balancing the plane will be the last step before I fly it.
I also removed the fuel tank to make sure the tubing was flexible and the clunk was moving like it should and that it was free of junk. After reinstalling the fuel tank, I couldn't help myself. I put some gas in the tank, pumped the prop several times to get fuel to the carb and started flipping the prop. After about 5 flips with the choke on, it fired up and surprised me. It ran rough with the choke on but, it ran. I shut the engine down and turned the mechanical choke off, flipped the prop a couple of times and the engine blasted to life full power. I almost had to change my shorts on that one. So, I shut it down again, reversed the throttle, and started her up. This time she needed idol and throttle curve adjustments which were easily done as I listened to the sweet sound of the engine running with pitts style muffler. I think this engine actually starts easier and idols a bit better than my other one. I haven't tried the smoke system yet but, all is hooked up and looks like it will work. It has the Sullivan Skywriter for a pump. I need to focus on getting the plane flying correctly before messing with smoke.
Once I get the CG worked out on this plane I think it will be a really good flyer. A few years ago I lost my favorite 50cc IMAC bird after both elevator servos burned out at the same time ( suspect it was caused by a failure in the Smart Fly). I don't have to describe the carnage from that. It was ugly. The Edge was from the same company (Goldwing) and flew really, really, well. It made me look like a much better pilot than I am and I'm hoping to get some of that back with this Sbach. We shall see.

Last edited by rowdyjoe; Mar 27, 2018 at 09:16 PM.
Mar 29, 2018, 07:32 AM
Registered User
Capt. Roll's Avatar
Awesome Garry! Sounds like you are on the right track to get the Sbach back in the air. Would continue to check every system on the plane, especially electrical to make sure there is no corrosion in the plugs and connectors.
Mar 29, 2018, 09:22 AM
Nose down, you're gonna stall
rowdyjoe's Avatar
Roger that. So far, all is looking good but, I'm still looking
Aug 03, 2018, 05:28 PM
Nose down, you're gonna stall
rowdyjoe's Avatar
The SBach flies great ...a lot better than I can. It's one of those birds that makes a good pilot look like a great pilot. Just wish I was a good pilot. Everything checks out but, I've made a few minor improvements. New gear, new alum. wheels & tires, and new shiny aluminum spinner. Now it looks as good as it flies.

I have not tested the smoke system as I wanted to get the rest of the plane in shape first. Now, I think it's time to tinker with smoke.
Aug 28, 2018, 12:54 AM
Nose down, you're gonna stall
rowdyjoe's Avatar
Denton Swap Meet treasure. There's Gold in them thar piles of stuff.

Treasure no. 1. picked up an "OLD" 1/4 Sig Cub airframe that I plan to strip and recover. It currently has the remains of a fabric covering I "think" might be Solartex but, since I've never covered in fabric I'm just making a guess based on what I've read. The airframe is solid and needs very little repair but, it does need some clean up. So far, I've stripped the cover off the fuselage, horizontal, and vertical. Now, I need to prepare the bare parts for reapplication of fabric. I've ordered a few feet of Ceconite Lite fabric to try out. This is my first attempt at covering an airplane in any kind of fabric but, I'm getting lots of help from an on-line forum I ran across while browsing. The guys on this forum are magicians when it comes to creating scale aircraft. I'm in awe.

Treasure no. 2. - I recently acquired a 38.5% (that's what the manual says) 81" WS ARF of an Australian Corby Starlet. A low wing monoplane replica of a very popular homebuilt in Australia. The airframe is in rough cosmetic condition but, structurally sound. While at the swap meet I discovered that Tom Blakeney had a Brand New (no box) complete ARF of this very airplane. (could have knocked me over with a feather) One thing led to another and I bought the ARF plus an extra fuselage from Tom for an excellent price. I'm still in semi-shock over finding this ARF here in the DFW area in like-new condition for sale by a club member. They are no longer in production and the odds of finding this plane in this condition on this side of the equator are astronomical ....and I just happen to have an engine that will fit it like a glove.
Last edited by rowdyjoe; Aug 28, 2018 at 07:05 PM.
Aug 28, 2018, 07:23 AM
Fort Worth Thunderbirds
Sunbyrd's Avatar
I haven't covered a plane with fabric covering for years but it's been my experience that solartex went around compound curves very nicely; better than films such as monokote. I covered an astro-hog and a telemaster in fabric and loved working with it. One of the projects in my queue is an old astro-hog airframe that I intend to cover in the same scheme as the first one I built.
Last edited by rowdyjoe; Aug 28, 2018 at 11:00 AM.
Aug 28, 2018, 11:00 AM
Nose down, you're gonna stall
rowdyjoe's Avatar
Originally Posted by Sunbyrd
I haven't covered a plane with fabric covering for years but it's been my experience that solartex went around compound curves very nicely; better than films such as monokote. I covered an astro-hog and a telemaster in fabric and loved working with it. One of the projects in my queue is an old astro-hog airframe that I intend to cover in the same scheme as the first one I built.
I've read comments like yours about fabric from quite a few folks and I'm looking forward to trying it.

Don't know if you've heard but, Solartex is out of business and there's no replacement for it ....yet. Balsa USA still has a few colors in stock but, it's going pretty quick. They also have a simple to use material called Planetex.

There are a couple Solartex replacement candidates and one is Oratex made by a company in Germany and sold in the US by a company in Alaska. It's intended for full scale and it's uncertain if they want to sell to the modeling community.
I've decide to use Ceconite Lite coupled with either "Poly-Tak" or "StixIt" heat activated adhesive. I have access to a small amount of Coverite and I may try using it but, not sure yet if there's enough to cover the entire plane.

Keep us posted on how your bipe recover project is going.
Sep 25, 2018, 06:42 AM
Fort Worth Thunderbirds
Sunbyrd's Avatar

Need Some Advice??

I started work on my second Polaris. It's been sitting in the box that it came in for two years. I'm finally getting around to building it, but ran into a problem.

As you can see from the picture, the motor thrust line is offset to the left. My first Polaris has no such offset, so I'm guessing that the foam has warped over time.

I'm also guessing that with the thrust line pointing left, the airplane is going to want to turn right. I don't see any way to straighten this out without damaging the foam.

I'm looking for opinions and possible suggestions. Should I shim the motor to the right a few degrees? Or, maybe just offset the rudder to the right?

Any advice will be greatly appreciate it. BTW, I posted a similar message in the Polaris Ultra group, but no one has responded and it looks like that group may dead.

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