New kid on the block - Smith Cub

[Buzzcola777]

Skywagon,
Yeap! Just a bit late for this! You're right, all the Pa-18s have seen so far do have the cable riding on the side. If it becomes a problem, I'll open up the inspection hole (I'll have to do it for the annual anyway) and fix it! On my control horns I twisted it already and does make a difference for alignment. I'm glad you like the felt over the leading edge because I have not seen too many of them...

 

[Steve Pierce]

I have an aileron bellcrank in my covering box for aligning the teardrop grommet and fairing during cover from the pulley above the rear spar to the cable attachment on the bellcrank.

 

[Buzzcola777]

The top aileron cable does not run parallel to the rib. However during covering the grommet and cover are often misplaced with the cable slot parallel to the rib. It should be angled to match the cable. Once it is on the usual fix is to simply cut/grind/bend on side of the cover slot so the cable does not rub. My cub has a perfect example of the quick fix mod!! With the covers you are making you could adjust the cover slot to fit the cable (looks like you may have done just that in one photo) and it would look great!! Excellent work as always. DENNY

View attachment A3250017.pdf
Denny, If you look at the attachment (Drawing #A3250017) from the blue prints, the cover is installed a bit sideways to accomodate the aileron cable that is coming at an angle. So you are right, I have enlarge the opening large enough in the cover to be able to take different angles. So, no rubbing and the cover stays align with the ribs! :lol:

 

[Buzzcola777]

I have an aileron bellcrank in my covering box for aligning the teardrop grommet and fairing during cover from the pulley above the rear spar to the cable attachment on the bellcrank.

Hey Steve, can I see a photo of this bellcrank?
Thanks!
Dan

 

[Buzzcola777]

Antennas - ELT & COM

Before, I begin this post I would like to thank Steve Johnson our Web Master for helping me out to debug my computer! I just could not upload photos and Steve fixed the problems by working his magic. Thanks again Steve, very appreciated!!!

ELT Antenna Installation

Excerpt from the FAA AC43,13-2B:

‘’When the antenna is not mounted to a conductive surface capable of providing a required ground plane for operation, a ground plane must be fabricated.
Most antennas require a ground plane size of approximately 24" by 24". While the rule of thumb is to provide a minimum of 1/4 wavelength of the operation frequency, larger is better and ground plane symmetry is critical. Gaps in antenna coverage or performance may occur if a ground plane is not symmetrical.’’

I also know that ELT antennas ONLY transmit from a vertical position. I understand that if you place an antenna inside a fuselage with a metal frame and/or metallic coatings (silver dope), it could dampens/deflects the signal.

All antennas need a ground plane. Bigger is better but due to the layout of the structure it is not easy to go with the recommended 24’’ x 24’’ based on the quarter wave length design. There is also the ‘’Faraday cage’’ where placing an antenna inside a metal structure WILL degrade the signal.
And the famous question about the location to install the antenna…

Lots of stuff to take into consideration especially for someone like that is no expert in this field.

So, I decided to go half & half. Half of the antenna inside the fuselage and the other half outside and supported by a ground plane made of aluminium (No. 4 on the list(out of 12 items) of conductivity relative to copper). Here we go...

Ground Plane


Making a template with max surface.


As you can see half of the antenna is inside the fuselage and the whip will be through the fabric with a bit of play inside the rubber grommet. If the aircraft is flipped on its back, it should be protected by the tail (crossed fingers) due to its location.


I choose the Kannad Integra 406 AF ELT GPS built-in (antenna & receiver)

VHF Antenna:


For this installation I bought the antenna from Advanced Aircraft Electronics. They advertised that silver dope is not a problem with this antenna and you don't need a ground plane...For Max sensitivity you must try to install it as vertically as possible.


Here is the best location I found for the antenna.


Piece of foam to secure the top. Strips of rubber to minimise rubbing





Next Metal Belly

Dan

 

[Buzzcola777]

Under Floor Metal Belly

Under Floor Metal Belly:

When I researched infos about this Metal belly, it seems that the main concern about this modification was scooping water(floatplane) or snow (on skis) into the belly causing all kind of problems. Here is what I suggest...


I had tabs welded by Nick when he built the fuselage.







So the metal belly goes under the metal plate. The metal belly is sealed with the foam. The metal plate is sealed with a rubber strip against the fabric (when installed) and snow will not be able to be scooped inside. Can't wait to try this!

More to follow

Dan

 

[Buzzcola777]

Floats - Mounts & Brackets

Before I start covering the fuselage, I noticed that the plates welded to the frame for rudder & balance pulleys were offset! It would have been a nightmare to fix this with the fabric on! So, I had to make an extension to one of the bracket to realign them.


I don't know if you can see but the top plate and bottom plate are offset by about an inch.




Now the floats water rudder & balance pulley mouts & brackets are aligned correctly.

More to follow

Dan

 

[skywagon8a]

View attachment 60227 View attachment 60228
Now the floats water rudder & balance pulley mounts & brackets are aligned correctly.

More to follow

Dan

Where is the tail of the airplane? To the right or the left? The way you have the pulley mounted it should be to the right. The load path of the two cable directions should be centered on the pulley bracket.

 

[Steve Pierce]

Hey Steve, can I see a photo of this bellcrank?
Thanks!
Dan

My daughter cleaned up and now I can't find it. :roll: It is a the center hinge/bellcrank from a Cub aileron.

 

[Buzzcola777]

Skywagon,
Tail to the left.
The pulleys should be flipped 180 degrees?

 

[skywagon8a]

Skywagon,
Tail to the left.
The pulleys should be flipped 180 degrees?

Yes.

The right hand one for the balance cable should not have the pulley offset from the center as is the left pulley, since the angle of the cable will be the same from both directions.

 

[Buzzcola777]

Thanks Sky!

 

[Buzzcola777]

Fuselage - Grommets & Inspection Windows

Before covering the fuselage, I took all measurements for the grommets and inspection windows thus avoiding guessing their locations. I downloaded the blueprint and reproduced these parts using 2024-T3 (.032) except for the one that goes around the elevator which I extended about 1'' inch.




A jig saw did the job




Also, all covers were cut and fitted. they will be held in place with metal screws and tinnerman nuts.

Dan

 

[skywagon8a]

View attachment 60240 Dan

Looks good. Did you allow for the arc defined by the leading edge of the stabilizer when you cut the slots in those cover plates?

 

[Steve Pierce]

I sell those water jetted. https://www.freewebstore.org/pierceaero/PA-18_Aluminum_Grommet_Set/p158560_304825.aspx

 

[Buzzcola777]

Yes Sir I did!

 

[Buzzcola777]

Steve! If I had know about it!!
Well, next Cub!

 

[Steve Pierce]

I got tired of the Pyralin grommets cracking, breaking and holes wallowing out and drew them all out and had them water jetted. I drill them with a #45 drill bit and install #4 PK screws. When the wallow out I install #4 Tinnerman nut plates.

 

[Bill Rusk]

As a customer, and user, of Steve Pierce’s inspection reinforcements, I can tell you they are the best. Much much better than the plastic. Thank you Steve!! I will probably be ordering another set very soon.

Bill

 

[Buzzcola777]

Plexiglass - Doors & Windows

I took a look at a lot of photos about how the plexiglass was attached to the lower door and there were all fixed with screws into the frame. It must be a tedious job to replace when it cracks... I think that, by encapsulating the window into a light aluminium frame, it would be better and easier if you have to replace it...Slide out the broken window, slide in the new one...


I started to drill holes into the frame... I stopped and decided built an aluminium frame for the window...I grabbed my 3-in-1 and made many strips.




Testing it with a piece of plexiglass


Tool used for cutting long pieces. Once cut, I used the bandsaw to bring it to the desired shape.


All parts cut and ready to assemble




Upper window - Once the plexiglass cut, I built a cap to seal the front area. Not to forget to use the proper drill bit for plexiglass.




Job done!!

More to follow.

Dan

 

[Steve Pierce]

Nice glass install on the lower door. I welded tabs to the top tube so no fasteners in the door window junction. I then layed out my holes in the square door frame tubing. Drilled and then using a nut plate jig drilled the rivet holes. Used a washer on a piece of safety wire to pull the nut plates through the tubes and maneuvered into place with a scribe, clecoed, 3/32" stainless countersunk pop rivets for the nut plates and it is all installed with screws for easy replacement later. Also welded an Allen head cap screw head to the outside of the door latch so the door can be fastened from the outside with an Allen wrench.
Pictures in this thread. https://www.supercub.org/forum/showthread.php?58562-Windowed-lower-door

 

[CamTom12]

Under Floor Metal Belly:

When I researched infos about this Metal belly, it seems that the main concern about this modification was scooping water(floatplane) or snow (on skis) into the belly causing all kind of problems. Here is what I suggest...

View attachment 60214
I had tabs welded by Nick when he built the fuselage.

View attachment 60215 View attachment 60216 View attachment 60217

View attachment 60218 View attachment 60219 View attachment 60220

View attachment 60221 View attachment 60222

So the metal belly goes under the metal plate. The metal belly is sealed with the foam. The metal plate is sealed with a rubber strip against the fabric (when installed) and snow will not be able to be scooped inside. Can't wait to try this!

More to follow

Dan

My metal belly mounts very similar to yours. Nice work!

 

[Hardtailjohn]

Dan, is that com antenna running up through the center of those ribs? If not, it's gonna stick out like a sore thumb and get beat to death by the fabric in flight......

John

 

[Buzzcola777]

John, it is outside. Thanks for pointing that out!

 

[Buzzcola777]

FABRIC - Part 4 - Fuselage

At last, it is now time to take care of the fuselage.
Started with the fuselage bottom and went with the ceconite heavy duty fabric. Easy to install due to the flat surface.




In anticipation of the overlap I marked the 1'' line using a gauge.

For the rest of the fuselage, I chose the Superflite medium fabric.




To insert the fabric into the window channel...You do what you have to do :lol:
This little iron from Top Flite is probably one of the best tool while covering.






I've glued wooden blocks and inserted them into the channels in order to hold the fabric firmly.


Time for grommets & tapes.


You don't want to run out of paper towel when gluing long tapes...


You can see here the Comm Antenna through the fabric.


Seaplane grommets / Bottom


From a dripping pan, I made the fairings for the rudder cable exit




Glued couple strips inside fuselage for the screws. Cheap fairings and easy to make.

Dan

 

[Buzzcola777]

Seats & Seat Belts

SEATS
I have flown a number of years with the cushion base / lumbar combo manufactured by Oregon Aero and really liked it. So, opted for their seats and bought 2 RV-7 / RV-9 seats from them and trimmed them to fit the cub.










SEAT BELTS
I bought the Crow restraint systems aimed at the RV Aircraft. Also got a set of retract mechanism on eBay that needed a bit of TLC...






Changing all belts with new ones...Measuring / Cutting & Sewing, thanks to my lovely wife!!

Here, I made a support for the retract belt (Pax seat)

...and connected the shoulder harness with the retract belt

I let somebody else do the recovering of the seat cushions. A skill that I don't have...

More to follow!
Dan

 

[Buzzcola777]

Upholstery

Leather & Tweed material were used for the upholstery. I might not be loading a hind quarter of a moose in the cabin for now. I'll wait a couple years...


Started with the cabin roof. Notice that I made a slot cover for the Pax retract belt.

Using a heat gun, I was able to curve the leather enough to fit the shape of the ''D'' window.














Upholstery is pretty well done! Ouf!!

More to follow.
Dan

 

[Buzzcola777]

Wheel - Hub Cap Cover

I wanted to buy a set of hub caps but the price was ridiculous. Just for the kick of it, I beleived that I could make them using my 3D printer. Here is what I did:[h=2][/h]

Hub Cap sold by Aircraft Spruce


Little drawing...





Voilà, for a minimal cost.

More to follow!
Dan

 

[Buzzcola777]

Baggage Doors

Now was the time to attack the baggage doors.

















More to follow!
Dan

 

[Scott A]

Looking good! Thanks for the update. I have read through your whole thread of course.

What is the width of your 3 in 1 shear? (sorry if you said and I missed it).

Any of the big tools you bought back at the start that you have found you didn't really need? Silly question, one can never have too many tools.

Scott