ckovacs

I've seen some Pica WACO's with gassers but they seem to all be of the side carb / side exhaust type. Has anyone mounted a rear carb gas engine on one of these? Is it even possible? I looked at the plans last night and things look pretty tight in there. I think I might be out of luck with my current ryobi conversion project as far as this plane goes but I thought I'd ask anyway. Might just try to find a homelite to convert for it.. The ryobi is a 31cc if that helps.


Corey

Stickbuilder

I think that you are going to be disappointed with how much engine is hanging out in the breeze with that much engine on the fifth scale WACO. I did my first one with the Maloney 1.25, and that was a tight fit. Not much power either. Mine now is getting the OS 1.60 twin (I know it is overkill, but it does have a throttle, and will all be inside the cowl.

Nothing looks worse (IMHO) than a pretty WACO with the engine hanging out of the cowl.

RCVFR

My Feedback: (7)

I'll second that!

ckovacs

Yeah, the more I look at the plans the more I agree. There is simply no "clean" way to do it on a waco this size.

Now, that being said Does the pica plans lend themselves to being scaled up to say 1/4 scale?

After seeing some of the larger waco's (33%) I'd be interested in a bigger plane.

Stickbuilder

Since the PICA plan does not have a parts call-out or take off, It won't be as easy as plans with the parts sheet to scale. If I were to blow the PICA to 1/4 or 1/3, I think I would trace all the parts, and have the plans blown, and get the parts tracings blown at the same time. Plan on spending some time here, since the parts are not identified, except on one page of the manual. Take your time and go piece by piece. clean up the die crunching on the parts (you don't want to transfer all the Fubars to the tracings). I've done this, and I think it's worth the effort. You will need to make allowances for things like spars and stringers, because when you blow from 1/5 th to 1//3 scale you are going from 1/4 X 1/4" stringers @ 20% to about 7/16 X 7/16" stringers, and these sizes are not readily available. Most of the time you can get by using the next size up, which will be 5/16" square or 3/8 square. Also the sheeting becomes a nightmare, because the length will require some serious splicing or you will have to buy odd size sheets. Don't let this intimidate you though. The WACO should be a great model in any of the larger scales. You will have to do your own thing on the ailerons to match the corrugations and such. I would consider finding an aluminum mixing bowl at Wally-World for the Cowl. You would be surprised what you can do with a 2 dollar hunk of aluminum from the housewares section.

Everything is going to be bigger. Even the silly Grin on your face after the first flight.

ckovacs

Wow, thanks for the reply Stickbuilder! If I am reading this correctly, you mean I should trace the actual parts as supplied by PICA? That make sense, and it's easy enough. Now I want to go look at the plans again, as I guess I don't recall seeing any
areas where parts are drawn, which is what you said above, just never realized it...

Doesn't sound all that difficult, and yes I am sure it would be well worth the effort. And besides, I've always got a silly grin on my face when flying my planes so whats one more.

To scale them up from 1/5 to:

1/4 do I just blow them up 125%

or 1/3 165% ?


finally, I've read that the PICA WACO builds heavy, where would you "lighten" things up? Seems like firewall and stringers, maybe tailfeathers and formers... Any more suggestions?

For a firewall, have you ever used a "torsion box" construction mehod?

Anyway, thanks again for that great reply to my question. I've never scratch built anything before and this looks like a good challenge.


Regards.



Corey

Stickbuilder

Yes, I used the box mount to get the Maloney 1.25 into my first WACO. No, the WACO does not build heavy. Check the wing area, and you will see that it is pretty lightly loaded. It just feels heavy for the Span of one wing (remember this puppy has two of them. You will loose a little weight if you don't use the box and beam motor mount that the kit came with. I've bought 2X4 wall studs that are lighter than the engine bearers. I'm going to run an OS 160 twin on this one, so I'll probably make a plywood firewall out of 1/2" aircraft ply. and use it instead of the first former. Also get a new cowl from Fiverglass specialists. It's lighter, and the rocker box blisters are more scale. While you're on the horn with them, get a set of fiberglass wheel pants. They are lighter than the built up wooden ones, and they last longer. I make the mount blisters for them out of fiberglass cloth and resin. I use an old kitchen spoon for a plug and lay them up over that, and sand them to shape. Lookks right, weighs next to nothing, and I glass them to the wheel pants. You can take a little (very little) neat out of the ribs, but the weight savings is minimal. Same with the formers. Remember, this thing has better than 1500 square inches of area, and at 10-12 pounds the loading is pretty light.
That 's about it. Talk to you later.