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Charlie’s Super Cub project

Someone thought this was a good idea on a Super Cub....

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Picked up the rest of the project today. After owning 4 PA-12's over the years this is my first PA-18.

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Full IFR panel. (That'll go away!)
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Boat anchor. (I'll go back to a fixed pitch.)
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Remote indicating compass. (I've never seen that in a Cub!)
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In the old days when you had to rely on a compass the further north the more need for it to work. You will see them up here in the old cubs from time to time.
DENNY
 
So the mission of this airplane will be to tow my glider, basic transport around the Puget Sound with occasional forays into Alaska to visit family and friends. I would also like to explore more of Alaska.

The mods I am thinking of off the top of my head-
*Gross weight increase.
*Extended baggage.
*Cubcrafters 3x3 gear 1.25”
*ABW wheels and brakes with probably a set of 31” tires.
*Rebuild the O320A2B into a 160 hp engine. (I think this is legal)
*Borer prop
*Simple instrument panel CGR30P, Trig comm probably a Stratus transponder.
*Tost tow hitch
*Poly Fiber covering with Aerothane finish.
*Dakota Cub fuel tanks.
*Cubcrafters header tank deletion.
*Folding seat and under seat battery.
*Maybe an AOSS gear system.
*Gear safety cables.

That’s all I can think of right now. My goal is to have the project done in one year. (We’ll see how that goes.)
 
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I like my buddy Mike’s paint job and instrument panel. I’ll probably do something similar except with blue instead of green.

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So the mission of this airplane will be to tow my glider,....... with occasional forays into Alaska to visit family and friends. I would also like to explore more of Alaska.

The mods I am thinking of off the top of my head-

*Cubcrafters 3x3 gear 1.25”
*ABW wheels and brakes with probably a set of 31” tires.
*Rebuild the O320A2B into a 160 hp engine. (I think this is legal)
*Borer prop

That’s all I can think of right now. My goal is to have the project done in one year. (We’ll see how that goes.)
Charlie, My thinking differs from many of the others so take it with a grain of salt.
Large tires create low down drag which in turn requires more nose up trim, thus lower cruise speeds.
3x3 gear lowers those tires, further increasing that drag. Sure perhaps some may not notice this drag but it will require more nose up trim which is drag.
The purpose of the 3x3 gear is to provide an increased wing LE angle to the ground for slower take off and touchdown speeds. The large tires do the same thing. Do you need both? With the associated increased drag? I would keep the stock gear with the big tires. That should be more than adequate for most situations.
The engine can be changed to a 160 via parts book minor alteration. To be used in the PA-18 an STC or a field approval placarding the tach to 150 hp would be required. I have one of these field approvals. With a fixed pitch prop there is no actual penalty since the red lined rpm will not be reached on take off.
Since you already have the prop governor installation use a Hartzell trailblazer constant speed prop. You will have full power available for towing the glider and a reasonable cruise speed for your cross country trips to Alaska. You will appreciate the higher cruise speed, particularly when coupled with excellent take off performance.

Replace the pulleys which have friction bearings with ball bearing pulleys. Then you can keep the cable tensions tight and the control responses crisp. Many seem to slack off the aileron cables to lighten the pressures. This prevents the aileron from going to full travel in flight since much of the stick movement is just taking up the slack, reducing roll authority leading one to believe that he needs VGs.
 
Charlie, My thinking differs from many of the others so take it with a grain of salt.
Large tires create low down drag which in turn requires more nose up trim, thus lower cruise speeds.
3x3 gear lowers those tires, further increasing that drag. Sure perhaps some may not notice this drag but it will require more nose up trim which is drag.
The purpose of the 3x3 gear is to provide an increased wing LE angle to the ground for slower take off and touchdown speeds. The large tires do the same thing. Do you need both? With the associated increased drag? I would keep the stock gear with the big tires. That should be more than adequate for most situations.
The engine can be changed to a 160 via parts book minor alteration. To be used in the PA-18 an STC or a field approval placarding the tach to 150 hp would be required. I have one of these field approvals. With a fixed pitch prop there is no actual penalty since the red lined rpm will not be reached on take off.
Since you already have the prop governor installation use a Hartzell trailblazer constant speed prop. You will have full power available for towing the glider and a reasonable cruise speed for your cross country trips to Alaska. You will appreciate the higher cruise speed, particularly when coupled with excellent take off performance.

Replace the pulleys which have friction bearings with ball bearing pulleys. Then you can keep the cable tensions tight and the control responses crisp. Many seem to slack off the aileron cables to lighten the pressures. This prevents the aileron from going to full travel in flight since much of the stick movement is just taking up the slack, reducing roll authority leading one to believe that he needs VGs.

I was dead set on going back to a fixed pitch prop but looking at the Hartzell Trailblazer prop has me very interested! I already have a governor that will probably work and the CGR30P has a manifold pressure gauge. I like the field repair you can do. I am going to look seriously at it!

As far as the 3x3 gear goes I’ll probably do it for a couple of reasons. When I am not up in Alaska I am going to run smaller tires. Maybe as small as 8.00”. There’s also a possibility that the airplane might be used for training. I like the idea of putting more weight on the tail wheel and better ground clearance.

I am going to replace the cables and pulleys. Where do you get the ball bearing type? Has this been signed off as a minor alteration? Does the FAA have any issues with doing it?
 
My ball bearing pulleys came with my Backcountry kit. You might inquire of them as to the source. Since my plane is Experimental I didn't approach the FAA approval aspect of them. Though I can not imagine why they could not be considered to be a minor alteration.
 
So the mission of this airplane will be to tow my glider, basic transport around the Puget Sound with occasional forays into Alaska to visit family and friends. I would also like to explore more of Alaska.

The mods I am thinking of off the top of my head-
*Gross weight increase.
*Extended baggage.
*Cubcrafters 3x3 gear 1.25”
*ABW wheels and brakes with probably a set of 31” tires.
*Rebuild the O320A2B into a 160 hp engine. (I think this is legal)
*Borer prop
*Simple instrument panel CGR30P, Trig comm probably a Stratus transponder.
*Tost tow hitch
*Poly Fiber covering with Aerothane finish.
*Dakota Cub fuel tanks.
*Cubcrafters header tank deletion.
*Folding seat and under seat battery.
*Maybe an AOSS gear system.
*Gear safety cables.

That’s all I can think of right now. My goal is to have the project done in one year. (We’ll see how that goes.)

Atlee Dodge has a big weld in extended baggage that is nice. They also sell Butch Cavaghna's big baggage door STC which makes baggage access very nice with the diagonal tube replaced with an inverted dog leg.

Dakota will give you their headerless STC when you buy their gascolator, fuel valve and gas caps.

I have been installing the Hawker battery in the stock location to keep the CG more manageable when not fully loaded.

Upper deck X brace?
Seat belt attach to the floor?
Bushing in the tail spring fitting, X or H in the tail and a 1/4-28 nut welded to the rear carry-thru tube. Metal panel on the belly from the jack screw back to the tail post.

I take it they had a big dich in the firewall for the prop governor?
 
Atlee Dodge has a big weld in extended baggage that is nice. They also sell Butch Cavaghna's big baggage door STC which makes baggage access very nice with the diagonal tube replaced with an inverted dog leg.

Dakota will give you their headerless STC when you buy their gascolator, fuel valve and gas caps.

I have been installing the Hawker battery in the stock location to keep the CG more manageable when not fully loaded.

Upper deck X brace?
Seat belt attach to the floor?
Bushing in the tail spring fitting, X or H in the tail and a 1/4-28 nut welded to the rear carry-thru tube. Metal panel on the belly from the jack screw back to the tail post.

I take it they had a big dich in the firewall for the prop governor?

I am going to go with mostly Cub Crafters stuff as I can drive over and get it. Maybe convince them I want to buy a Carbon Cub and go for a test flight. ;)

Good idea on the battery install especially if I stay with a constant speed prop!

I'll probably do the upper deck X brace and maybe L-21 windows. I am debating both. I am not familiar with the seat belt attach to the floor. Yes on the aft belly close out and H in the tail. What's the 1/4-28 nut on the carry through tube for?

The ditch in the firewall is for the prop governor. It's actually a valve cover.
 
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Pilot seat belt to the floor and top deck X brace are a must on every Super Cub I have rebuilt. Here is a thread with pictures of the seat belt mod. The pictures of the instrument panel will make a believer out of you but I chose not to post them. https://www.supercub.org/forum/show...-attachment-floor-vs-seat&p=764588#post764588

There is an oil hole on the rear carry-thru fitting where the stabilizer pivots when trimmed. I have found these rusted and sometimes rusted to the centerless ground hard nickel plated liner tube thus bowing the stabilizer when the trim is manipulated. By welding a 1/4"-28 nut over the oil hole you can install a grease zerk and grease that pivot.
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I install the stabilizers and elevators and verify full nose up and nose down trim on the stabilizers and control deflections on the elevators. You would be surprised how many Super Cubs do not meet the type certificate data sheet in this regard and have never been bent or repaired. Same with the angle of incidence of the wings.
 

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From your description I don't know what cross tubes you are referring to. The only issues I have seen with fuselages have been in the tail where they get twisted between the jack screw and the tail post. Every other issue structurally that I have seen has been environmentally or pilot induced and the tail is pilot terrain induced but that is what we use them for.
 
A model fuselage in for repairs right now. Diagonals to the tail post are twisted one has a repair. The two diagonals from the jackscrew down to the lower longerons were installed in all of the A models I have worked on and in the last of the Lockhaven Super Cubs. I have never seen or noticed the tube between the two bottom longerons and the diagonal in front of them going between the two handles but they are shown on the A model fuselage drawings I have.
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I have had to drive quite a few out. Had a PA16 come through here with a PK screw through that hole after a fresh rebuild. This one a few years ago takes the cake, brand new Airframes fuselage.
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I have had to drive quite a few out. Had a PA16 come through here with a PK screw through that hole after a fresh rebuild. This one a few years ago takes the cake, brand new Airframes fuselage.

How were the trim pulleys after that?
 
A model fuselage in for repairs right now. Diagonals to the tail post are twisted one has a repair. The two diagonals from the jackscrew down to the lower longerons were installed in all of the A models I have worked on and in the last of the Lockhaven Super Cubs. I have never seen or noticed the tube between the two bottom longerons and the diagonal in front of them going between the two handles but they are shown on the A model fuselage drawings I have.
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So a 180 hp engine caused the need for the tube over a tube repair and the addition of the vertical tube or was there a wreck in it's past. Have seen the longeron crack behind the rear horizontal fitting on 160 hp Super Cub that had been wrecked. Never seen any issues there on anything I maintain. The Husky has a solid tube there, non-moveable stabilizers. Aviat issued a service bulletin that mainly effects banner and glider tow aircraft for increasing the wall thickness of this tube.
 
So the mission of this airplane will be to tow my glider, basic transport around the Puget Sound with occasional forays into Alaska to visit family and friends. I would also like to explore more of Alaska.

The mods I am thinking of off the top of my head-
*Gross weight increase.
*Extended baggage.
*Cubcrafters 3x3 gear 1.25”
*ABW wheels and brakes with probably a set of 31” tires.
*Rebuild the O320A2B into a 160 hp engine. (I think this is legal)
*Borer prop
*Simple instrument panel CGR30P, Trig comm probably a Stratus transponder.
*Tost tow hitch
*Poly Fiber covering with Aerothane finish.
*Dakota Cub fuel tanks.
*Cubcrafters header tank deletion.
*Folding seat and under seat battery.
*Maybe an AOSS gear system.
*Gear safety cables.

That’s all I can think of right now. My goal is to have the project done in one year. (We’ll see how that goes.)
Add belly pod tabs to that list if you’re going to AK
 
Give the folks at Dakota Cub a call about ball bearing pulleys. They are a really nice upgrade! 605-757-6628

—Amy


Sent from my iPhone using Tapatalk
 
- Lift handles on both sides like in Steve's photos
- weld tabs on door opening bottom tube to attach interior panel
- 3rd seat STC. Even if you never intend to put someone back there, it increases your baggage area legal load and adds a couple of good cargo tie downs points.
- welded on float fittings?
- what are your plans to mount shoulder harness? Note that many add a small cross tube when they add the upper X-brace, to run the pilot's shoulder harness through. Improves the angle of the strap on your shoulders and keeps it out of the passengers face.

I know, every little bit of metal adds weight. All depends on the mission.

Jim
 
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Order all 4 not just the two in the wing and say you’ll order the other two when your close to finishing the project. They changed suppliers and didn’t have them when I went to order at the end of the project. You will also need the cages as well, they are different. The pulleys make a huge difference. Put just the one on the struts and wow. So much smoother


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- Lift handles on both sides like in Steve's photos
- weld tabs on door opening bottom tube to attach interior panel
- 3rd seat STC. Even if you never intend to put someone back there, it increases your baggage area legal load and adds a couple of good cargo tie downs points.
- welded on float fittings?
- what are your plans to mount shoulder harness? Note that many add a small cross tube when they add the upper X-brace, to run the pilot's shoulder harness through. Improves the angle of the strap on your shoulders and keeps it out of the passengers face.

I know, every little bit of metal adds weight. All depends on the mission.

Jim

I am trying to keep it light. No intention of putting it on floats so I am not going to do the weld on float fittings. I’ll figure out somewhere to attach shoulder harnesses for both seats. Probably just weld on a couple of tabs. Hadn’t thought of doing a 3rd seat. I’ll take a look at it.
 
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