Len's Czmelak "Smellyak" build

[lenb]

Len's Czmelak "Smellyak" build

Pete Goldsmith designed this airplane primarily as a tow plane for aerotowing of both large and small scale sailplanes. The prototype is powered with a DA 150 on standard mufflers. The prototype was constructed in about 6 weeks, from drawing to test flight and since then, the Czmelak, which we all affectionally call the "Smellyak", has performed flawlessly



My Smellyak build

This build started back in the middle of the summer, this large cardboard box contains all the wood, gear and cowl to build the plane.

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Start by gathering all the part for that particular task. Here the rudder template, ribs ( for both sides), the tailpost and caps are all ready to go.
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Fin posts are thick balsa, well designed to help eliminate excess weight

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Peter designed the control surfaces to be build over a pre-cut 1/64 ply template. You frame over each side of the template and the result is a strong stiff control surface or in this case the vertical fin

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In this photo you can see how the 1/2 ribs are glued right to the ply template.

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Flip it over and do the same on the other side


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Here we are installing sheer webs to help support the vertical fin spar

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Sub LE and TE are installed


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[Stew2]

How do you like the "Speed Bond"? I haven't used any of the fast drying alphatic glues, yet.... Waiting for a CA allergy to develop apparently.

[JimD]

Len bought two lifetime supplies of Speed Bond adhesive, so he sold some of his stock to me. Having used it now for a substantial amount of structural work, I can say that I am impressed...probably going to be a fanboy!

[Sinkhappens86]

Looks good now that we can see all the photos Len! Looking forward to Steve K starting his!

[ErichS]

Like the Ply skin method. Hope the 1-26 will be like this.

[lenb]

Im sure it will, the Swallow is the same way,

[lenb]

I cleaned up the thread a bit, thanks for the help with the photos guys.


Onto the Stab and Elevator.

Non of the building I have done is over the plans, its all done with using the pre-cut parts and making the spar straight on a piece of sheetrock or just the table.

The Stab is assembled over the lower spar. Use the sheer webs for rib spacing and make up the center section using all the ply ribs Peter has in the kit.
Pay attention to the sheer webs, keep the pieces held tight to the ribs and the ribs 90 degrees to the table. Its pretty simple construction.

[lenb]

The elevators were built on a pre-etched skin also, again-very clever.

Nothing magical here, pretty straight forward. You'll need to sand the LE off the angled ribs to get everything to fit perfectly.




Glue on the LE sub spar, use a straight edge to make it perfectly straight from the start.





They appeared a bit long, no big deal, I'll sand them down before adding the top sheeting. It's balsa, sand and trim until its the way you want it.










Here are the parts roughly sanded. I'll put these aside now and start the wing. Final sanding will be done at the end.

[ARUP]

Noyce! Fast building, too!

[lenb]

Thanks Mike,
This build started a while ago, I'm just now getting to post the progress.

The wing center sections are next.

Again, I did not build any parts over the plans, just using the pre-cut parts as the guide.

The center starts with gluing up the joiners. Take time fitting and testing the parts together as there is always a logical reason and process for the way it's designed.
When in doubt, walk away and come back later for a fresh look.

[kjkavaney]

Thanks Len for posting these pictures as they are timely as I am at this point now...there are no side views on the plans so I was very confused as to where the spruce spars went and where to cut them, but now with your photos I get what needs to happen next...
kevin

[Mosquito]

Len, what's the status of your build? Your followers need a fix!

[lenb]

Hi Tim.

My computer had to go in for a new screen, luckily apple's warrantee covered it, but I didn't have my photos for a while.
The plane is much further along than this thread indicates, but I'll post photos in sequence.

The main wing panels were next

[ARUP]

I see two pilots guys in the background, waiting!

[kjkavaney]

Len, your pictures are timely as I am about to start work on the outer wing panels and your photos are worth ten thousand words...I can finally "see" what I could not see before...
I frequently feel over my head on my build but am glad you are there to rescue me when I am almost out of air...
kevin

[lenb]

Random Photos of Peters Prototype​​​​​​​

[lenb]

At this point I have set the wings and tail aside, I still need to build the ailerons and finish the flaps, but since Kevin is moving along on his build and time may become and issue for me shortly, I wanted to build the fuse and get the photos posted.

The fuse is built by starting with the cabin area. Lay out the side pieces and start fitting the parts.

Advice:
Take your time and pull out all the fuse formers and parts you can identify. Lay out the side panels and dry fit everything. Once you've marked locations with a pencil and your sure of the location and fit, then start cementing thing in place.

I started with the rear anti-rotation double. Since all the pieces seemed to be based on that doubler, I started there and worked forward.

You will be framing the edges with spruce, so once you're happy with the location of the anti-rotation double, fit the spruce around the perimeter and glue all those pieces in.







Thinking ahead.

You will be joining together the main spruce spar that runs all the way to the tail, instead of fighting with it now sticking out there and waiting to get broken, I went ahead and made the scarf joint cut now on the pieces that will join, numbered them and set the two rear strips aside until later. The BOTTOM stringer will be joined later and can be just left a little long at this point.