Eagle Flyer

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For those interested I thought I would post some pictures of my 4* 60 on the sheeting job.

Eagle Flyer

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Here are some of the wing's leading edge and also I sheeted the outer wing rib to protect it. You can also see where I added a thick piece of balsa on the outer rib in case I need to install some screws later for lateral balance.

rwright142

Very nice. What technique did you use to soften the wood so you could bend it so much?

Eagle Flyer

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Actually I didn't have to do anything. It bent all the way with out breaking. But it felt like it was getting VERY close to doing so. So I rough cut them out then applied them with no glue, just a lot of rubber bands. But used a heat gun to help bend the 1/64th plywood. That let it lay right over. Then let it cool to help hold it's shape. After cutting and sanding till I was happy with the fit then I would reapply with rubber bands to insure proper placement. Then apply CA. The heat helped eliminate the under frame from reflecting thru the sheeting as it would round it out. Also I used a full sheet of fine sand paper and very easily sanded it by pulling the whole sheet over the turtle deck at one time. This takes the high spots off the edges of the balsa stringers so they don't show thru.

Kmot

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Wow, that looks great! So, the sheeting is 1/64 plywood?

Eagle Flyer

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Yup. 1/64th ply. Not the cheapest way to go but the thinnest I figured. Since those pictures were taken the wings are done with the sheeting as is the fusealage. I have enlarged the elevators and rudder. About the only thing left to do is finish straightening the ailerons. They were warped. About done with that though. Then start on attaching the wing and control surfaces without glue to fit them properly.
The balsa sheeting on the inner part of the wing I recessed a little with sand paper to lay the plywood into then blended it in with sand paper.
I will get some pictures of it with the finished sheeting.
I also enlarged the F2 and tank tray just enough to allow a Dubro 16 oz. tank to slide thru. Then I built doublers for the weakened parts to bring the strength back. I already had a 16 oz. in my old 4* and wanted to stay with it. It had a removable raised tank cover. Which worked nice as I could inspect my fuel level or tank components at any time.
And I put a true fiberglass cloth with epoxy over the wing joit.

blw

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I used probably the same wood to cover a foam turtledeck. It came out really nice like yours. I soaked mine in water and bleach for a while before using Probond with rubber bands.

Eagle Flyer

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Here are some pics of it's current stage. Also you can see the hardwood blocks on the landing gear plate in stead of balsa. And some added balsa between the one turtle deck joint to give a little more support between the stringers.

Deadeye

Looks nice, and I'm sure ou will be happy with the finished product. Just a FYI, the leading edge on the 4 Star contains 'turbulators' (or so I was told by a fellow RCer) They are designed to 'mix up' the air, especially at slower speeds, to stabilize the wing. As much as a floater as the 4 Star is, though, sheeting the LE will probably help with the landing. Full scale Ag planes actually use turbulators attached to the wing in all sorts of crazy looking configurations. This is to help them evenly disperse chemical.

blw

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I asked Bruce Tharp if he designed the 4*40 wing to use the spars as turbulators. He said that he did not; he used that method to keep the parts count low and to save weight. He said that he was sure the spars did act as turbulators due to the performance of the wing.

4*

Hey, that's great! I did the same thing. Nothing flys like a 9 1/2 lb .60 size plane!
My second one was built stock. Flew great at 8 lbs. Go figure.

Eagle Flyer

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Well after a summer of everything else going on I finally got back to work on it.
I doubt I added 1 and 1/2 lbs. of 1/64th sheeting and glue, though there must be a couple ozs. there. But I also clipped the wing 1 bay each side.
Got most of the covering done. Also added a couple extra balsa stringers for support under the front top cover. I can see myself grabbing too hard there. That is a Dubro 16 oz. tank. Fit fine and is easily removable with a couple simple mods. See pics.
I am looking for the info and pictures on how people turned the canopy around for a different look. But can't find it. Can any body help me there? Or ideas on others that fit?
Still debating on going with the fiber glass cowl. That Cap 21 cowl looks nice. Have a Saito 125 sitting here.
I was thinking of enlarging the ailerons. Some one suggested just putting the large end to the outside. Any one ever tried that?

blw

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Enlarging the ailerons on the tips could promote flutter since they are strip ailerons. The Sig Kavalier has that problem at high speeds. Also, the tips is where you will be vulnerable to either tip stall problems, or vortices for sure. The best bet is to narrow them at the tips and widen them towards the wing roots. The flutter possibility is remote, but vortices interferring with aileron control isn't.

There was a website with mods to the 4*60 but I think it is down now. This is where the guy shows how to carve a nose cone block. He turned his canopy around and angled it to make is smaller, if you can visualize that. It did look good. The site was www.renderwurx.com/rc/sig4star.

Eagle Flyer

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I figure there is a reason why you never see it done that way.
I'm pondering leaving the trailing edges of the ailerons square. The manual says to round them off. An older 4* I have that was built by some one else is done that way. He built several over the years. It always flew and landed fine.
As far as the turbulator thing goes, if that is the case then loosing a little lift is ok. My stock 4* is a bear to get down if there is much wind. I've even landed it with the wind cause going into it, it simply just won't stop floating. That's one reason I clipped the wings.

ChuckW

When I widened the ailerons on my latest 4* 40, I rounded the tips and there has been no problems with fluttering or tip stalling. The clipped wing also gives a much better roll rate with not much affect on the landing speed.

MormonMike

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Chuck and Eagle, Hmm..... Quite impressive, matter of fact, very impressive. MM

blw

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Chuck,

Nice looking plane and aileron ends. That should give a slight advantage aerodynamically.

Eagle Flyer,

The wing span is most likely the main thing keeping the 4* floating. The turbulator provides better lift across the entire airfoil. You can think of it as helping the air to stick to the wing instead of being pulled away just past the leading edge. When this happens, the air usually reattaches to the surface at some unpredictable point like near the ailerons. Small turbulator devices on the British Harrier jet allowed the pilots to pull an extra G in tight maneuvers, such as dogfighting. The plane will handle better at all speeds and your stall characteristics will be better with the turbulator, but I also agree that sheeting the wing looks much better. I haven't decided what to do with my kit yet.

I wrote Bruce Tharp, who designed the 4*40, and asked him about the wing. He said that the stringers probably did act as turbulators, but that he designed it this way to keep the weight down. He is a nice guy and likes to talk with people who build his kits.

If anyone sees the Blade CX electric coax helicopter, look at the rotor blades. You will notice a zigzap pattern raised on the rotor blades. That is a turbulator. I don't know if the new CX has those, but my original version does.

Eagle Flyer

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All but finished with the covering. Just have to trim the wing some and do the ends of it. OK I know it looks a little bright but that is just what I wanted. I'm not too artistic. The balance came out nice. All I had to do was move the servos all the way forward and add a heavy hub using my old engine mount. I could have got a new one and moved the engine forward about 1/4 " but decided not to mess with it. Also found that my new Saito 125 will bolt right in and weighs the same as the TT 91 in it now. So later in the summer I may advance to that. I went with a removable servo tray so I could remove the oversized 16 oz. tank if need to. Also by putting it all the way forward it holds the tank in place with some foam in between. For some reason pictures won't work at the moment so I will post later. OK pics are working. I was pondering the canopy thing and remembered one I had. It came from an expired Futana 40. It's turned around backwards and trimmed a whole bunch. I kind a like the looks of it except it has a few scratches on it. But that doesn't bother me too much. They are always scratched it seems like by the time I get them mounted. Several coats of wax will do wonders for them.

Eagle Flyer

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It's all done. Just waitin' for spring like weather now. Will probably put in the Saito 125 later if this shows good promise. So now I can move on to the next projects, finishing up a couple other planes. A CMP Katana 140 that needs some final little things and then hopefully either Great Planes Yak 1/4 scale or Byron Extra 28%.
A couple pics of it.

Eagle Flyer

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I finaly got the job finished, and did a maiden this morning. After a final check and tune job, up it went. All it needed was 2 clicks of down trim. No surprises and flew great. Only did the one flight as there were some realy strong and weird currents at the end of the runway on the way in. Up/down then lay left and right etc. All when it was only about 10 foot up. Been flying there for several years and have never seen that before. And the Avistar did the same thing. Decided not to test my luck any further. Besides, it was the first time out this year for me! Now all I need is more time on a better day.

Eagle Flyer

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Memorial day weekend I went out Sunday. Was out for several hours. Flys great. No surprises all day long. Only thing now is to move the cg a little. And maybe later put in the bigger 125 engine. Another winner in the 4 Star book.

Mustang Fever

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Eagle:

Everyone should have a 4*. Yours sure looks great.