Big_Bird

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Are you following the incidence settings from the plans or are you setting up the wings differently?

No, I'm not using the plans incidence. I have a friend who has built 3 of the Pepino Wacos. The first one was built like the plans showed. He said that, with all of that incidence, it took off like a home sick angel. It required additional down trim and the trim changed with different engine RPM. The next 2 he set the wings and stab at zero and the planes flew great.

I set the bottom wing at zero and the stab at zero. The top wing will be set at -1 degree. To set up the cutout that I built into the fuselage wing saddle, I took the pattern of a full size wing rib and placed the ends of my Robart incidence meter on it. I drew a straight line from the point of the V on the leading edge of the incidence meter to the point on the trailing edge of the meter. This was then transfered to the center section wing rib and the plans. The same was done for the top center section. As you can see from the first photo, the fuselage wing saddle required extra bass wood above the saddle to allow for a larger cutout than was shown on the plans. If the additional cutout were not made the center section would be below the contour of the fuselage.

Did you take any of these items into consideration or did you build yours by the plans?

mango12

Ken, I did indeed follow your recommendations on the lower wing saddle, at least I think I got that from you. I added a piece of 3/8 bass to the top of the wing saddle for the extra support. I have been really curious about all of the incidence built into this model. I never even checked it on my FlyBaby, but the two Ultimates I have had were both set at zero and I loved the way they flew. A Goldberg and a Dave Patrick, liked the Goldberg best.
Scott

Big_Bird

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Yea Scott I think I mentioned it much earlier in the thread. Of course, even a modified Clark Y airfoil still has lift when the incidence is set at zero. I sure hope it flies like I think it will. Another good friend built the 1/3 scale Balsa USA Fokker D-VII. He has a lot of experience in aircraft design. He said all of the BUSA D-VIIs that he had seen did not fly as good as he wanted his to fly. He did the same thing and took the extra incidence out of the wings and stab. Man does it fly good. Here are a few photos. Note the elevator position in photos 2 & 3. Note the incidence in photo 4.

mango12

I hope to finish the bottom wing panels over the next couple of days, then I'll start setting her up. netural on the bottom wing and stab, -1 on the top. Guess we will see how it works out. That D-VII looks great by the way.

Big_Bird

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Hi Scott,

So far the most difficult thing to work out on this plane has been what to do with the fillets on the wing saddle. You can't imagine how many hours I have spent looking at my plane and looking at photos of the full scale. As it turns out it is impossible to accurately duplicate the full scale because the lower wing is not deep enough into the fuselage even though I moved it in some. Poor design.

Here is what I did so far. I used 1/64" ply to line the wing saddle and add the parts that I thought it needed. It was put a part on and stand back and say "that looks about right" or "nah". After the parts were glued on I started putting in a little DAP super light spackling. Here are the rough photos. It will look a lot better after I do a bunch of sanding.

What did you do?

skylarkmk1

BB,

It is a bit late for you, but the photos may help. They are of a 1987 YMF Classic, NC 14081, that was at the AWC Fly In, July 14-17th. On the original 1930s YMFs the fillet seems to be one fuselage stringer lower and extends a little further back along the fuselage. My reference for that is the National Waco Club web site photo section.

Big_Bird

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Thanks a lot John. These photos confirm that I do have generally the right shape.

mango12

Hey Ken, you are ahead of me just a bit !!!! What I had thought about doing is this. I was going to cover the model before adding the fillets. That way, when I add the filler and do the sanding, the panel line should already be there. All I'll have to do is prime and paint. I figured that would be easier than trying to cover that inside curve. Have you ever tried this, or do you think it is not such a wise idea?
Scott

Big_Bird

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Scott I believe the fillets on the full scale, as shown in John's post above, are metal and screwed on. Regardless of the type of filler that you use there will be a lot of sanding and I am afraid that I would sand into the covering. I don't think the full scale fillets were fabric covered. I plan to fiberglass and paint the fillets when the plane is painted.

skylarkmk1

BB,

You are correct, the fillets are metal and screwed to the wing on top with a "rub cap" along the fuselage. Look at the underside photo and you can see a line of screws running fore and aft with a few more in stratigic locations. The trailing edge is riveted, similar to the ailerons. The upper side photo shows the few screws on top along the wing and at the overlaps and that the fillet panels are mounted rear panel first, then the middle, then the front.

mango12

You know, I didn't even think about sanding through the covering!! Sometimes I think too far ahead. Your plan sounds like the way to go.
Scott

Big_Bird

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I plan to fiberglass first and then carefully trim the covering before I stick it down.

I got away from epoxy a long time ago for fiberglassing when I discovered Minwax Polycrylic clear satin. I use it straight with a brush to put the first coat down. I then mix talcum powder with it for filling the weave. This combination works great. Best of all, you can wash the brush out with water. Just don't wait too long.

I was really hoping to have this plane ready for Bomber Field in mid September but I really don't see how I can. Time is really flying. Fortunately I have 3 other big birds that I can take down.

mango12

Just can't build 'em fast enough. Our field has been shut down since this past November for renovations and the addition of softball fields by the locals parks and recreation authority.I was hopeing to have mine finished for opening day, but I don't know. They say our field is going to be the premire site in the south. Maybe I can talk them into a Waco fly-in !!!
Scott

Big_Bird

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WOW, an all Waco flyin. If it's there like it is around here you might get 4 or 5 Wacos and I live in a big metropolitan area. Dallas/Ft. Worth.

You know, all of that sheeted area in front of the cockpit and around the front end should also be fiberglassed. Uh oh, that means lots of panel lines and screws. And then there is the ................. Definitely won't make Bomber Field with it.

Here is the color scheme that I plan to use. A Canadian registered Classic Aircraft.

Big_Bird

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Here is the final on the wing fairing before I add the fiberglass.

mango12

I see you do not have the anti-rotation dowel at the rear of the wing. What method are you using? And yep, if there was an all Waco fly-in here we may reach a dozen pilots, at least ten would be flying ARF's !! But if all of the "Brotherhood" were to show...........

Big_Bird

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One piece wing. Top and bottom

old git

Pure aluminium has a higher melting temperature than Al alloys. The material used to braze aluminium is an Aluminium alloyed with 10-12% silicon. This has a slightly lower melting temperature. It must have an Aluminium Flux, Chlorides and Fluorides of Sodium, Lithium and Potassium. These are spoiled if allowed to remain damp for any length of time. I have some Al flux but guess it has spoiled with time. The flux is very corrosive and must be removed with hot water. The aluminium job needs support while heating because the Al gets soft with heat. The flux is best mixed with alcohol and applied as a paste before any heat is applied.

Immediately before welding the Aluminium and the filler rod must be vigourously cleaned (typically Stainless Steel-wool is used). Support the job on a refractory material and with a soft slightly carburising (smoky) flame the Oxy-Acetylene flame is waved across the job, NEVER stationary. The flux paste protects the Al from excessive oxidation as the heat of the flame warms the flux and job. If the job shows slight wrinkling while being heated you are about to loose it as a puddle of Al. As the Al brazing rod gets hot and melts it should run around the joint using capiliary attraction.

Aluminium welding or brazing removes any work hardening and leaves the job fully annealed. Brazing Al is probably the most delicate of the thermal procedures. Try it on scrap first, not Al alloys can be brazed. You can probably not braze Al pistons, cylinders, crankcases or most castings. They are robably made of the same high silicon alloy that the brazing rod is made. Leave Magnesium alone. They can all be welded with the correct rod and flux.

There is a prorietary Zinc rod that can produce a joint of slightly less strength. The rod is heated while in contact with the Al job. It scratches the oxide on the job allowing a bond between the Al and the filler metal. It does not require as high a temperature as welding and no flux is required.

It is possible to resistance (spot) weld many aluminium and other alloys together using a resistance (electrical) spot welder. The heat is not generated in the copper electrodes because they have good electrical conductivity. Placing the Al job between the copper electrodes roduces little heat because the Aluminium is also electrically very conductive. placing a small amount of steel between the copper electrodes and the aluminium job enables heat to be produced and a Non Fusion weld to occur. The difficult oxide layer is broken up by the deformation of the interface.

I am pretty sure full sized aluminium cowls are still welded using Oxy-acet and flux because it gaurantees nice penetration and no cold shutting. It is then hammered to shape losing the lump of the reinforcement bead and hardening the material by work hardening. NOTE again aluminium and its alloys are softened by fusion (melting) welding and to regain the strength of a typical Duralumin the WHOLE job must be heat treated to regain the original strength.



WACO Brotherhood No. 14.

old git - - - - - - aka John L.

JoeAverage

snip
I discovered that the horizontal stab and elevators were not drawn symmetrical. I copied one half on my light box and used it as the pattern for both sides. On my plans, if you lay a straight edge on the horizontal trailing edge, it curves off.

Looking forward to seeing how your mount works out.
[/quote]

The issue of symetry is very important of course but I don't think enough people are aware of the lack of it. I'm glad you mention it but not that it was a problem for you. I was commisioned to build a big expensive kit for a fellow many years ago and before construction I always trace the bulkhead or whatever, and then flip it over and retrace it using the top line for reference.

The bulkheads were routed and out by a mile. From the firewall to the one in front of the tailpost. It got more expensive to build as I had to cut all new formers. I have done this checking method since then. Most parts from most sources unless laser cut, hence mirrored for a cut file, are usually out. When building I always pick the best looking side of a pattern and mirror it with a pattern. When designing I draw one side so the builder can make a symetrical part. I haven't seen any other references to this problem so I am glad to see you forwarned readers. It is a universal problem/concern.

Cheers, John

Big_Bird

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Hi John,

Glad you dropped in here. Are you building a Pepino Waco?

I have done quiet a bit of building from plans including Hostetler's PT-19 (2 each), and 1/3 scale Super Decathlon. Also Ziroli Corsair (2 each) and B-25. I never gave symmetry a second thought on those plans. They were dead on. These Pepino plans have been a pain in the a**. I have listed a lot of the problems in this thread so that readers, who are contemplating building one, would be aware of some of these mistakes.

The plane can be built into a nice one. It's just a shame that Jim's drawing skills and lack of accurate measurements had to spoil such a nice project.

Here is what the belly pan cover looks like. Of course it was not shown on the plans because the wing would have been so far below the fuselage that it wouldn't need a belly pan. As is my wing is not deep enough in the fuselage to be scale. I quit worrying about scale a while back.

skylarkmk1

BB,

I am glad to see that you are adding the belly pan, it is often overlooked and/or forgotten. A few pictures of the belly of YMF Classic, NC 14081;

P1 Front view
P2 Side view
P3 Side view of the front area

JoeAverage

Big Bird,

I'm real glad that you have taken the time to point out some of the quirks in the plans. To tell you truth I was going to abandon the project most likely but with the help you have provided I may proceed. Would you do it all again? Anyway, like I said, I'm a lot more likely to do it having your thread to refer to. I'm sure there are other in the same boat.

I have the glass parts and plan, couldn't get the wing joiners from Iron Bay but I wasn't sure about them anyway. I like the one piece idea and have a good trailer. Had I not been so anxious initially I may not have bought the parts so quick.

I would really like a bigger YMF. I did the Platt and Pica thing back when. I really didn't think the Pepino would require so many corrections. I looked over the plans and figured that the use of a string or "batten" being my preferred tool, a long small dimesion stick, a throw back to the boat building I did years ago, was going to be essential to locate stringers.

I have a Bucker and a couple Pitts among a couple park flyers to finish off. I'll let you know if I start one. In the meantime I will closely watch your excellent progress. It's these problematic designs where a building thread is a huge benefit to the modeler.

Cheers, John

Big_Bird

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John, thanks a lot for the photos. Does that Waco belong to you? It sure is a pretty one.

Big_Bird

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John, after buying the glass parts and the plans I guess I trapped myself into building the plane. I did get very discouraged after closely examining the plans. However, I'm very glad that I pushed forward and I think this will be a very nice plane when I finish.

Here was my last big project, a 1/3 scale Bucker Jungmeister. It took a second place award in 2004, a first place in 2005 and a second place in 2006 at Bomber Field in Monaville Texas.

skylarkmk1

BB,

Don't I wish, it belongs to Robin Williams from Michigan. He was the only YMF that attended the American Waco Club Fly In at CCA/HARM back in June and I tried to get the detail shots modelers need. I have about 180 pictures that show most parts of this plane. It is a 1987 YMF Classic, serial # F5-009, NC 14081, built by Waco Classic Aircraft Corp. in Michigan. Since it is a modern version of the 1935 YMF, some details do differ (wing fairings, cockpit instrmentation and exhaust ports for example) but the outlines and general construction is almost a direct copy of the original. Alot of the pictures have been posted on the WACO YMF thread in Vintage and Antiques as the area in question comes up.

I am fortunate to live about 50 miles away from Creve Coeur Airport near St Louis, MO. It is home to the Historic Aircraft Restoration Museum (HARM). It has about a dozen Wacos in the collection, but no YMFs. Most of the 60-70 museum aircraft are maintained in flying status or are being restored to fly and many are one of a kind or few. The most recent aircraft restored to flying status is the De Havilland Model 4 or DH-4 for short, the only one currently flying in the world from over 4000 built during WWI. There are many other interesting aircraft based at CCA (there are about 95 hangers total) from Wacos, Pipers, Travel Airs, a Pete"N"Pual, Stearman PT-17s to a Mustang, AT-6s, the big 6 passaenger Skyraider and a T-28 in S. Vietnam Markings.