RysiuM

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I'm buildng 23% PZL 104 Wilga 35/80. Quite big plane 100inch span and 1500sq inch wing area. The estimated weight is going to be around 15 lb. I was planning to use converted Poulan 25cc. It runs MA 16x8 classic at 7400 rpm. Is is enought for that plane?

I put all the parameters of my Wilga to RealFlight G2 (based on Cesna 182) and then I simulated the engine torque based on the rpm I measured on my Poulan 25. I was surprised this 'combo' flew very well on RF G2 (better power than the full scale).
I used RF G2 to simulate my other planes and it was quite accurate in the flying envelope. But I'm sill not sure how accurate it is.

So this is the question to your experience with scale giant flying . I fly mostly acrobatic and experimental planes, so I'm not sure how the engine/plane combination shuld be for scale flying of planes like Wilga. Will 25cc do the job? Will it be enough to tow small (2-3m) gliders? Or do I need to look for something like 40cc-50cc ?

RysiuM

sir-crash-alot

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hey nice to see you again if you look in the crash picture and discussion you will see my edge lol! good news is that plh is sending me a prototype plane to test out!

Crusty

Rysium, are you sure about that target weight?, they are usualy closer to 20lb and flown on 50-60cc engines, maybe youu have soom serious weight reduction plans eh?

RysiuM

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I believe I can get it around 15 lb. Of course it is to early to say for sure, but I'm doing all to get to that target. I have the whole fuselage tramed up, stab + elevator framed and custom made scale landing gear. That's what I know for now:

1. Scale landing gear (with wheels) 26 oz (13 oz each). I don't see any way to reduce that - one DuBro 5inch wheel weights over 4 oz.

2. Fuselage frame is 36 oz. With balsa sheeting and covering it should be around 3-3.5 lb. I modified original plans so the fuse frame is made of all hollow light ply formers and carbon fiber tubes (except the enginebox-langing gear mount-wing mount part).

3. Horizontal tail is 10 oz now. All it needs is covering and hinges.

I estimate that the build up wing should be around 3 lb. I'm going to make it as light as possible using carbon fiber spars and CF LE/E inserts. The finished tail should be around 1 - 1.5 lb. My goal is to have the ARF around 10 lb. I don't expect to have more than 5 lb of engine-radio stuff in there.

This is my goal. I tested this setup on RF G2 and I really like the way it flies. But even at 20 lb it behaves great with that power. But can I trust RF G2?

BTW here is the small Wilga I built a couple years ago. 36 inch span weights 24 oz powered by Norvel 0.061 (recently I converted it to electric gaining a lot more power and reducing the weight to 20 oz)


RysiuM

Crusty

Rysium, when you brake it down like that it doesnt sound too optimistic..good luck.
I have g3 and have been trying to emulate a ultra stick with it but Ive fiddled with it too much now and its not even close. at one point It did seem to be getting there,...sometimes I think some of the parameters behave in unexpected ways, but I am still learning how to use it.
Oh and personaly I just cant see how anyone could think a Wilga is ugly

RysiuM

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It is my beloved plane. It is beautifull Not only that. It flies great.

RysiuM

Boogie

Wilga is beautiful!! I have few planes locally here (they are polish designs). The best one there is, is the Wilga 2000. It looks so d@#$n nice!!

RysiuM

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I believe PZL did a great job upgrading the old 35/80 for all the benefits of full scale flying. However it did loose some STOL parameters (stall speed increased by 20 km/h, and twice longer take-off and landing run) but what is most important for us, modelers, it does not look as good as the old one. The new one looks more like common Piper or Cesna, but there is no other aircraft in the world, that looks like Wilga 35/80

RysiuM

cheechukranch

Where did you get your plans? I like this idea...

RysiuM

My Feedback: (1)

I got them from UK (magazine). However they don't sell them any more as plans are totally screwed up. So many errors - in example the wing has 12 inch chord, but the wing mount on the fuselage is 15 inch, fuselage formers don't fit fuselage, impossible wing mount, wrong horizontal tail incidence, LG doesn't hold up, and many, many other small gliches.

As I'm building the plane I'm fixing these plans. Hopefully they may make them abailable again.

RysiuM

Crusty

AAh...those plans, good luck with them,...youll need it

RysiuM

My Feedback: (1)

What do you men; 'those plans'???

I admit, the task is challenging, but not impossible. Here are some fuselage pictures taken over a month ago (I need to take some new pictures for update). You can see that from the plans I took only the shape of the formers but the construction is quite different. The landing gear mount and enfine box are different to. They are mounted to the main former (not the floor like the plans show) that is carying the whole plane all together.

The main flaw in the plans is a lack of strong key points. All the forces loading the plane are from the engine, landing gear and the main wing. The plane I'm building is designed around the main former (thick and strong plywood). It conects the wing, landing gear and engine box. The rest of the construction just needs to be stiff.

I will post new some pictures soon.


BTW I read some info about the guy that used 1/4 Piper for towing 3m gliders. Piper was electric power spinning 10x8 at 5k rpm. This is the same power and static thrust I got from my Poulan 25. So maybe it will work.
RysiuM

RysiuM

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I'm almost done with the Fuselage frame. I need only stringers for sheeting, but I will wait with that when I will know how I'm going to mount the tail. It will be much easier for me to do something inside the fuse without the whole net of thin squares. But entire 'construction' is done. It is strong and stiff. And weights only 2.5 lb.

Here are the pictures showing the frame with details on the strong points. You can see for example a 'scale' tubes behind the windshield. In fact they hold the front of the center wing with the engine box.

The home landing heas with gas springs (30 lb each) will hold even rough landing. The full deflection will be at about 20-25 lb on each wheel. It is quite heavy, but there is no way to lighten it up without loosing structural integrity. Even these 4.5 inch Du-Bro wheels are heavy.[]

The stab (my son is working on that) will have scale hinges. The same will go with rudder, ailerons and slotted scale flaps. The only 'scale' element that will be missing is the LE slot.

RysiuM

Crusty

looking good Rysium, I have not tried the plans myself, I considered them, then heard the stories and finaly read the apology that the magazine had to make and thought no-ill leave it
hats off to you for accepting the challenge.
I am sure you will end up with a beautifull wilga..dont forget the picss

RysiuM

My Feedback: (1)

Believe me, the plans ane not the best quality in the world. I have scratch built a couple planes already, and this one is the toughest. Even 36" span Messerschmitt BF-109 from expanded Guillow's balsa model plans was easier. Guillow's plane were much more accurate and much easier to work with.

Before I've seen Wilga's plans I was expecting something like I used to see in AMA magazine but with some errors or mistakes I could easy correct. I was a little surprised when I got them, however I accepted the challenge. If I was able to build [link=http://m.modelersinc.home.comcast.net/bee/bee.html]3/4 size Lazy Bee [/link] (original plans shrunk to 72%) I could build Wilga too .



After looking more detail into the plans I found, that actually all the pieces I wanted were there: formers, templates cabin design, wing and tail airfoil. I had to double check everything (comparing the measurments on each view to make suer they fit) and some needed corrections, but I got the general idea what to do and how the plane supposed to look like. Guys from the magazine attached also two issues of their magazine: the one with original plans and the other with the review by the guy, who actually tried to build the plane based on that. It was very helpfull too. I believe his 'mistake' was that he tried actually to built that Wilga exactly like the plan shows

Please, don't get me wrong. I don't complain. Even more: I'm very thankfull to Andrea, who let me buy these plans, even they were removed from the market. I was aware thet plans had errors and I was willing to correct them myself. It's just kind of funny, that some guy could create such thing. I believe, plans were created as a revers engineereing, and many components or corrections were not included. What I mean, if you built the plane exactly like the plans show, it wouldn't fly for sure. But I hope, my plane will[8D]

RysiuM

RysiuM

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Update.... Hmmm, there is no any. Before I started the wing I decided to get some practice building GS wings. I got wing kit from OMP for GS Edge 540 (80" span) that I'm converting for H9 Edge. I see now, how big boys are doing that, and now I have some idea how to make a wing for Wilga. Now the building board is still occupied by OMP/H9 wing so I will start Wilga's wing when H9 is done.

Today I got CF wingtube from CST. I needed 3ft for H9 but 3ft of T170 at CST (3/4" CF tube) cost the same as one piece of T170-6 (same tube 6ft long). So I got T170-6 and for the shipping CST cut it in half. 3ft goes to Edge, 3ft will be in Wilga.

RysiuM

RysiuM

My Feedback: (1)

It's been a while since I updated this thread

OMP wing is flying on my Hangar 9 Edge 540, so I got back to Wilga. I have entire frame almost done and now I hit the proplem. The wing will have sloted flaps. I still didn't figure out how to make right hinges. So far there are some pictures of the first put-together

RysiuM

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Many things happened since the last post. Wilga got wings finished, new stab and elevator, and the fuselage is sheeted with depron. Tail wheel is powered by its own servo and wing got working landing lights and custom made tow release for gliders. Slowly but surely work is going on.

Tired Old Man

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Excellent work!

Back to the original question of engine size. First, I would not put too much faith in the comparative accuracy of G2 or G3 to simulate your plane, weight, engine combo. If you can keep the weight below 14 pounds then I believe that a 25 to 26cc gasser will fly scale just fine. Above 14 pounds with your wing area I believe you would need to come up just a bit in engine size.

RysiuM

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Because I decided to use this plane as a tug for gliders, 25cc is not enough. At the same time, 2.5lb in the nose (the weight of my 25cc engines) is not enough to balance the plane. So I decided to go with Fuji 43EI. Ready to fly weight is about 4.5 lb (with everything, that I can put in the nose) and 7k rpm with 20x8 prop will give enought thrust tor the plane with 7-10 lb glider attached.

Engine is on its way

RysiuM

My Feedback: (1)

I decided to use Fuji 43EI and it works great for balancing the plane. I made my own spinner nut for kind-off like Wilga looking. I still need to design and order custom exhaust system (header and can muffler).

Still a lot of work with the plane, but I got all wings and tail done including servo installation. Now I'm working on covering the fuselage. Here it is, how the plane looks now. Because the fuselage's tail is sheeted with depron it is a little tricky to put a ultracote on it. Depron stays OK up to 210F, that is the temperature for the glue, but it will melt whe you try to heat shring the covering.

JeffH

My Feedback: (43)

Here is mine. It's a Frisch Kit with a G-62. It weighs 26lbs dry, and more than enough power. I will be able to tow 5-6m sailplanes when done. It will haul a 4m almost straight up. You should be able to fly yours on 25cc EASILY. I could put a G-38 on mine and still fly it with comfort. Mine will take off in about 10 feet now, and land in about 20 with full flaps.
I admire your tenacity to scratch build like that.
Jeff

RysiuM

My Feedback: (1)

Thanks, but I had no choice. I had limit for the lenght of the plane (the size of my truck). The smallest Frish is stil to big for me. The plans I got were also to big, so I shrunk them to 90%

Few months after I started this plane I found 20% Wilga (fiberglass ARF), but I was to deep into the project already. And building from scrach gave me a chance to do some personal touch (like landing and strobe lights).

I put Fuji also for additional reason - balancing. I need 4-5 lb in the nose to balance it right. The whole tail is built light but all tiny things easy added up.[]

RysiuM

My Feedback: (1)

The project is going for over year and half now, but still going. Right now it is in the phase of installing equipment in ARF. My next deadline (the third one already) is New Year Flying. Not much time left, but if nothing wrong happens, not much work left either.

I modified Texan-like cowling made by [link=http://www.fiberglassspecialtiesinc.com/]Fiberglass Specialities[/link] by adding cowl louvers and this changed the appearance 100%.

Because I couldn’t install remote choke, I installed remote ignition switch as an alternative way of killing the engine. This way I have everything related to the ignition under the cowl in front of the firewall. Far away from he radio.

I couldn’t fit any reasonable size fuel tank in such way, that would be hidden inside the plane. Finally I decided to use two DUBRO 16oz tanks connected I series. 32 oz gasoline should be enough for long, long flights.

I tried the plane with the prop I had (mejzlik), but the scale-like props are on the way to California. They are made specially for me by [link=http://www.smigla.com/index.htm]Grzegorz Biela[/link] (you probably heard about “Smigla Biela” or “Biela Prop”). He makes many scale props including props for [link=http://www.smigla.com/mak1.jpg]Frisch Wilga[/link] (like a real one)

However he didn’t have the size I wanted. So he made a scale-like prop painted (in the plug) like original Wilga’s prop.

Finally because with these stick-like landing gear the plane looked funny, I installed balsa pants. Now it is much better

Plane is still missing all radio and power connections (but all servos are already installed) and of course I need to design and make some kind of interior. The last thing I will do is installing the windscreen. Right now I have very easy access to the plane.

The last weight estimation placed this plane in the vicinity of 20lb (hats to you, Crusty) . More than I thought, but still acceptable.

Pictures below.

RysiuM

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Wilga is finished. Today was the first flight., This is just giant scale trainer

[link=http://www.rcuvideos.com/view_video.php?viewkey=e02287c374fd26835d87]Video from the first flight available on RCU [/link]

Few pictures just before the flight and from the video below.