skylarkmk1

Bob,

To look right and to be scale, both the top and bottom wings have 2° on each side. This is also on Paul Matt's drawing (Historical Aviation Album) of NC 14031, the Pica subject plane.

BOBFI

My Feedback: (5)

I am going to start this project and have Pepino plans so this thread has given me insperation much needed information. Great job guys.. As I have never built a bi-plane before, Is building washout into the wings of a bi-plane a common practice or not?

obo

My Feedback: (37)

Thanks John I was perty sure it did but I wasn't sure that it needs 2 degrees in the top wing I was afraid it look funny. But if that be the case then I feel ok to put the 2 degree in THANKS.

Bob
Waco Brotherhood # 35

mango12

Bob, Ken nor I are building washout in the wings. I don't think the washout is necessary on a model like this. I think the purpose of it is to prevent tip stalling on landing, which I am sure none of will do anyway.In looking at the plans, the washout is formed using the inner-plane struts. I am not sure how this is accomplished. It seems to me that trying to do this would pull the trailing edge of the bottom and top wins together, which would in effect cancel out the washout, and probably cause a whole new set of problems worse than tip stalling. Ken, correct me if I am wrong please. "Skylark" or some of the guys might be able to tell us if the Pica kit or the ARF has any washout in them. I have never had a biplane that did. Hope this helps, and good luck. Keep us posted!!!
Scott

skylarkmk1

BOBFI,

The PICA wings are built flat. The last 3 ribs in the tip (W-6, W-7 and W-8 on the Pica plans) are where any "washout" occurs. The last W-6 needs to be shortenened in hieght slightly along the bottom (tapered) at the trailing edge to be correct. The tops of W-7 and W-8 are nearly level with the rest of the ribs (along the spar/high point), while the bottom angles up and the result raises the trailing edge in that area. The aileron curves up in the same area and the curve up actualy starts between the last 2 W-6 ribs. The YKS and YMF wings are similar in construction (they use the same aileron) and I have had access to the YKS while it is being restored.

P1 Covered full size YKS top wing
P2 Uncovered full size YKS top wing, you can see how the last 2 ribs are "tilted", raising the trailing edge.

Big_Bird

My Feedback: (1)

I have never intentionally put washout in a biplane wing. I really don't think it needs it. I did put washout in the two Ziroli corsairs that I built per Nick Ziroli's instructions. Warbirds are a different story.

Here is the way the tip came out on my Pepino Waco. Unfortunately Pepino doesn't give much information on the way the tip should look. Does it look alright or how would you change it if you could?

skylarkmk1

Ken,

It looks ok, don't mess with it. On the next build I would raise the trailing edge and center of the tip a little. The full size when measured along the spar/high point has the rib W-7 (second from tip) about 1/4" lower and the W-8 rib (last rib) about 5/8" lower. This makes on a 1/4 scale, W-7 about 1/16" low and W-8 about 5/32" low. Compare your picture to the uncovered wing in my last post.

P1 Trailing edge of wing at aileron hinge line. Note upsweep on lower edge start well inboard (between last 2 w-6 ribs) and just the last little bit of the top curves down.
P2 Leading egdge of aileron with matching curves
P3 Aileron bolted in place, note the last few ribs of the top of the aileron (between the end of the hinge and tip) curve down, just barely.

JoeAverage

I appreciate your dialog on the Pepino. I'm making notes for my build. Yours and others remarks will help greatly.

mango12

Joe Average, that is an interesting article. Do you have it in it's entirety?
Scott

JoeAverage

Yes. I didn't know the whole thing would load. Enjoy.

mango12

Thanks! Printed it to add to my collection.

JoeAverage

Your very welcome. If I come across any more similar material I will post it as well. This stuff is not very plentiful. Once it a while something just comes up from an old periodical.
Wm. John

Edit: I should include that that page came from Raymond H. Brandley's "Waco Aircraft Production "1923 - 1942"

Mr. Lucky

Great article. I had trouble printing it though. It kept chopping off on the sides for the margins. I just saved it to my pictures/documents and then printed it from there. I only wish the pictures could be printed larger. I'll have to work on that.

Makes you want to build a big one doesn't it? Like my dad always told me. It's just a giant model, you just want to make sure everything is perfect and built to withstand a cataclysmic event keeping in mind weight.

JoeAverage

I just posted them like I got them. It's been a while since I've printed anything but I think there is a % tool for centering image on page from the print menu. I once printed everything, put it all in document holders, made covers and realized it was just eventually going on the fire when I expire. Who will want a lifetime collection of Pitts, Bucker, Travel Air, Stearman and Waco documentation when I'm gone?

mango12

Ken, have you been able to do much on your Waco? Between out of town trips and football games, I haven't acomplished much. I did get my dummy engine in finally, and have started working on the headrest/ dorsal fin.
Scott

Big_Bird

My Feedback: (1)

Scott, I haven't done anything lately. I hope to start on the second wing panel this week. Which dummy engine did you order?

mango12

I went with the Bob Dively 1/4 scale version. I know it's not the correct engine, but it will be close enough for my purposes. Can you give me the dimensions of your head rest/ dorsal fin? The height, and width at the rear of the cockpit would be very useful. Mine looks tall and skinny. Thanks

Big_Bird

My Feedback: (1)

I have not installed the head rest/dorsal fin. Have not even shaped it. Here is a photo of that area currently. I assume that you bought the 7 cyl. P&W 7" diameter dummy engine. How does it looked taped into your cowl. Can you make a photo of it and the dorsal fin and post it? Photos mean a lot more than descriptions. Here is a photo of the Dively 11" dummy engine in my Jungmeister. It might be too large for the Waco.

mango12

Wow, that looks pretty darn good !! I'll have to get it trimmed up tonight and place it in the cowl. I'll try to get some pictures and post them in the AM. Don't know if I can get it painted first but will try.
Scott

JoeAverage

Considering my options. I don't compete or get out much so if I have no dummy engine I have a cool engine. The DE-502 is shown with the flash at the TE of the Pepino cowl. This dummy is a maybe in this cowl The OA Dia. of the engine is 10". 10.5" with the flash flange left attached. A 25% R-760 would be 10.62" in Diameter. If I shaved the heads and Dremelled out the blisters, it might fit.

The DE-502 will fit any of the 1/4 scale cabin cowls easily. I'll need more. Large smooth cowl is one of many I have for Waco's and 25% Behrens Travel Air 4000D, maybe the Pepsi Skywriter version. 12.25" X 8.5". It will be nice to have some room for a change.

John

mango12

Ken, actually I bought the 10" P&W that Bob Dively produces. I got it sorta painted and the flashing trimmed, was about to put it in the cowl, and realized there is no front opening cut out of my cowl. Here's what I did, and an interesting discovery I made.
Since I stopped working on my Ziroli Texan to build the Waco, I had the Texan cowl laying in the way and stuck the dummy engine it just to see if it fit. Not only does it fit, but the cowl is nearly perfect for the Waco!! It is only 1/16" deeper than what is required and doesn't have the blisters, but that will be a simple fix. The Texan cowl is MUCH sturdier than the one I have for the Waco, so I am going to use it. I took pictures of the headrest/ dorsal fin and the engine/ cowl last night, but the batteries died before I could get them downloaded, so I'll post them Friday AM. Have a great Thanksgiving.

JoeAverage

Scott,
May I ask what the diameter and depth of the Texan cowl is. I have been wanting to hang onto the Pepino cowl for a 1/4 UIC, UKC as it would make it distinctly seperate it it from the genre of 1/4 scale cabins that exist now.

I am leaning towards a smooth cowl for my Pepino. There are a bunch that had no blisters and with an 3.25" AT-6 spinner would look really sharp. I' like the little larger a diameter cowl to maybe put a spare twin in as well. AT least a G-62. I like the breathing room around the larger cowl. With a big spinner I may even pass of the dummy engine. A 3WB2 has it's appeal as well. By that I mean I like still model airplanes that look like model airplanes. It my scalitis in check.

Thanks, John

Big_Bird

My Feedback: (1)

Very good info that you two have come up with. I ordered a DE-502 dummy engine from Dively today. It will get cut down a little more than the same engine that I used on the Jungie but I still think it will look good. Please ignore the Zinger prop. I'm saving it to stir house paint.

I have actually started back on building. I'm working on the second wing panel.

mango12

John, I'll have to remeasure it when I get home, but I believe it is 5&3/4" deep and just slightly over ten inches in diameter. I'll post the exact deminsions Friday along with pix.
Ken, glad you got going again.
Scott

JoeAverage

Looking good Ken, That looks like one of Ed's Precision cowls. Am I close? The models I see here lok straight and true but I have seen the odd Pepino model with stringer issues.

I have an approach that I use a lot for subjects where accuracy in drawing and building is req'd. A technique I learned at my daddy's knee. While he flew for a living and didn't assist me much with my modelling he did teach me a lot about building boats.

Having gathered a few tips on where the Pepino needs attention I am thinking that when I place the formers on the fuselage box I am inclined to employ the use/method of a "Batten" to get the fuselage halves true and symetrical side and side alike. Notches increase the strength and being there, by Jim's design, lend excess standing thickness to work with in achieving the accuracy and symetry desired, whether the notches are in the right location or not, there is that bit extra height. I had thought of just tacking the formers onto the fuselage "sides, top and bottom" were applicable, temporarily, and then once having them accurately lofted, to then be removed, redrawn for future ease of assembly, then permanently replaced in order to be able to simply glue the stringers in the right position longitudinally again using the "Batten" and know that the stringers will right the height as well.

The stringer being in a notch can't hurt but I think in the example of the "Ikon N' West" UPF-7 with its accurately outlined formers, which require the builder only to locate the stringers on the formers where indicated is a good method. To be assured that it's longitudinal position is accurate as well as it's standoff height without any guessing must be a treat.

For the benefit of those not familiar with the Batten I will add a couple pages from an invaluable hard cover titled "Small Boat Construction" by Robert M. Steward. published 1954.

The complex, pleasing and purposeful lines of a ship or an airplane are derived at using many of the same techniques. If I am building a scale model from scratch I will often use a Guillow's like half fuse to establish my shape. It works well.