RE: Jim Pepino's YMF-5 Waco  
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RE: Jim Pepino's YMF-5 Waco - 7/10/2007 9:33:53 PM   
Big_Bird



Posts: 3148
Joined: 12/18/2001
From: Arlington, TX, USA
Status: offline 		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?

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Ken
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RE: Jim Pepino's YMF-5 Waco - 7/10/2007 10:10:54 PM   
mango12


 

Posts: 206
Joined: 3/19/2007
From: duncanville, AL, USA
Status: offline 		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


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Scott
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RE: Jim Pepino's YMF-5 Waco - 7/10/2007 10:32:07 PM   
Big_Bird



Posts: 3148
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From: Arlington, TX, USA
Status: offline
quote:

ORIGINAL: 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

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.

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< Message edited by Big_Bird -- 7/10/2007 10:36:18 PM >

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Ken
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RE: Jim Pepino's YMF-5 Waco - 7/10/2007 11:35:59 PM   
mango12


 

Posts: 206
Joined: 3/19/2007
From: duncanville, AL, USA
Status: offline 		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.


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Scott
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RE: Jim Pepino's YMF-5 Waco - 7/15/2007 3:33:03 AM   
Big_Bird



Posts: 3148
Joined: 12/18/2001
From: Arlington, TX, USA
Status: offline 		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?

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Ken
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RE: Jim Pepino's YMF-5 Waco - 7/15/2007 4:17:54 AM   
skylarkmk1



Posts: 1112
Joined: 9/25/2004
From: Festus, MO, USA
Status: online 		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.

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< Message edited by skylarkmk1 -- 7/15/2007 4:19:51 AM >

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John F Howard (aka skylarkmk1)
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RE: Jim Pepino's YMF-5 Waco - 7/15/2007 3:09:15 PM   
Big_Bird



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From: Arlington, TX, USA
Status: offline 		Thanks a lot John. These photos confirm that I do have generally the right shape.

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Ken
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RE: Jim Pepino's YMF-5 Waco - 7/15/2007 11:29:24 PM   
mango12


 

Posts: 206
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Status: offline 		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


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RE: Jim Pepino's YMF-5 Waco - 7/16/2007 12:49:00 AM   
Big_Bird



Posts: 3148
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From: Arlington, TX, USA
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quote:

ORIGINAL: 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

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.

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Ken
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RE: Jim Pepino's YMF-5 Waco - 7/16/2007 1:28:21 AM   
skylarkmk1



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From: Festus, MO, USA
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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.

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John F Howard (aka skylarkmk1)
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RE: Jim Pepino's YMF-5 Waco - 7/16/2007 7:28:22 PM   
mango12


 

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From: duncanville, AL, USA
Status: offline 		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


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RE: Jim Pepino's YMF-5 Waco - 7/16/2007 9:55:18 PM   
Big_Bird



Posts: 3148
Joined: 12/18/2001
From: Arlington, TX, USA
Status: offline 		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.

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Ken
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