Building a Javron Cub

Bill Rusk said:

Paul

I have the fuel pod and that gives me (when installed) 68 gallons of fuel. My burn is approx 7.2 to 7.5 an hour. That gives me around 8 to 9 hours of endurance and my cruise is around 104MPH. So....all that said.....I flew from Lynden WA (on the border north of Bellingham) to Ketchikan non-stop. Thus I overflew Canada and did not have to worry about their restrictions. It is about a 6.5 hour flight and I still had 17 gallons when I landed. Yes, that is long and it gets pretty tiring but it beats clearing customs twice, and the covid mess. I have self quarantined in the Forest Service Cabins.
It is nice to be able to remove the fuel pod when not needed to save the weight. Some folks prefer to use a cargo pod, and stop to refuel, but it is certainly nice to just pump it up in flight. This is especially helpful when on floats. Dragging a 35 pound fuel bag up on the wing while bobbing around on a lake, hoping you don't drift into a shore, or tree, in the rain, and wind, while standing on a wet slippery float, is not as easy as being on firm ground in a wheel plane. There are advantages to each concept. This one works well for my situation. YMMV and all that.



Hope this helps

Bill

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The floorboards and wet feet.....am I the only one to use a deep ribbed car floor mat that captures all the crud, sand, and melted snow before it runs down the inside of the plane? It's been one of the best small mods I've made on my S-7, and I like the traction it gives my heels, instead of sliding around on the plywood. I landed a sandy beach just the other day and getting back in made me appreciate the mat once again. Your description of standing on a float to refuel with a bush bag made me laugh, sounds like fun, and for sure that belly pod and a pump is the only way to....go. I have similar endurance in my S-7S, (with half the capacity but also half the burn rate) also with electric pumped fuel transfer, easy and safe, in flight or on the ground. Carrying a outboard motor makes perfect sense, to this ebike carrying pilot.

Paul
Airglass does make a combo (part fuel and part cargo) pod for the PA-12. It holds 18 gallons of fuel. I don't think the fuel pod for the PA-18 would fit. They are molded pretty specifically to fit a particular shape. I will stop by and look next week. Good to hear from you.

Courierguy
It certainly might help but I'm not sure how it would work with heel brakes. I'm guessing you have toe brakes and a different floor configuration. One of the things I would do different is to put a metal belly under the front cockpit area to allow easy clean up/out. All summer getting in the airplane with wet boots/waders, often with gravel and sand on them, is pretty hard on the airplane. The belly area gets cleaned at annual but it is a pain to take the front floor boards out. Remove the seat, remove the torque tube, remove the rudder pedals, etc....all of which are a pain to get in and out. Sounds like you have your airplane set up to fit your mission. It is great when you get everything dialed in. Sure makes it fun to fly. I will look you and lowrider up when I get settled in this fall. Best regards

Bill

Does your cub weigh 1388 lb with your Whip's? What is your gross? thanks

NoCub

Empty weight on Wip 2100A amphibs is 1325 and gross is 2300. Thus useful load is 975. (Empty weight on 31" bush wheels is/was 1052) Gear weight was roughly 127 and the floats weighed roughly 400 the way I installed them (hand pump only)

Hope this helps

Bill

Folks

I was Blessed to have a great summer, in spite of all the Covid drama, and here is a little video of my Alaska summer. About 3 1/2 minutes.

https://youtu.be/bWd9wcu4_28

I hope you enjoy it


Hope this helps...... motivate

Bill

Awesome, thanks Bill

Hey Bill,

How does your airplane perform fully loaded to 2,300 lbs. in real world conditions? Is it mushy, more squirrelly, or heavy on the controls?

Have you noticed a sweet spot for CG and weight and loading where the plane feels “just right?”

Are you at all concerned about operating at gross?

What a great way to wake up in the morning to a scenic trip to SE Alaska in you magic carpet ride!
Thanks Bill.
I’m getting very close to joining you in the sky with my build.
Bob

Thanks for posting. Looks like you had a great summer.

Bob - Thanks and I look forward to seeing you this summer. I look forward to seeing your latest and greatest. It should be quite the workhorse.

Paul - It seems to fly great even at 2300 which I am at a lot in the summer. 400 pds of pilots, 200 pounds of gear, and 300 pounds of fuel. Takes about 20 seconds to get off the water when at gross. As the GW goes up the CG envelope gets smaller until at gross it is only one inch. I am using the CC 2300 gross Top Cub TCDS weight and balance envelope. Using the prop face my CG range is 70.5 to 80" The sweet spot seems to be around 75. It requires the least trim and the harmony feels best right about there. At full gross the CG is at 79". It does not feel squirrelly at that CG probably because I am only at that CG when I am at 2300 pounds. I have figured out my loading system so I think I am pretty close. At gross you can tell if the CG is off because it can be harder to get up to the high plow point (second rise), or harder to push over on to the step if the CG is not right. I have never had a problem getting to the step, but I can feel when it is harder to get there.
Like most amphib cubs it is at the forward CG limit (most are over) and that allows me to load the baggage compartment pretty aggressively and not go out the aft end of the envelope. When just playing around the local area, ie not full of camping gear, I put 30 pounds of lead in the tail to bring the CG closer to the sweet spot and it makes the airplane handle much much better.
I have full confidence in the structural integrity when at gross. I have seen some pretty bad turbulence in the late fall in the SE and it has done fine so far.

Hope this helps

Bill

Bill Rusk said:

Folks

I was Blessed to have a great summer, in spite of all the Covid drama, and here is a little video of my Alaska summer. About 3 1/2 minutes.

https://youtu.be/bWd9wcu4_28

I hope you enjoy it

Hope this helps...... motivate

Bill

Click to expand...

Bill,
Beautiful video!
Thanks for sharing
Dan

Folks

Thought I would post a little from my 1000 hour annual.


Just a nice picture of Sandpoint Idaho




Airplane in front of the hangar



On the hoist. It is a LOT easier to work on when it is on small tires and lower to the ground.



I like to remove the entire tail assembly every year. This area is pretty much totally inundated with water every takeoff.



Along with cleaning and regreasing, it is a good time to look for cracks at the welds. In a perfect world you would not lift on the horiz stab to beach the tails of the floats but it is not a perfect world. So a thorough inspection of all tail parts is in order.



Looking for cracks here as well, and on all the tubes on the fuselage.



It is a good time to replace hardware that is showing wear. Hinge clevis pins.



It gets pretty nasty under the floorboards. And it is a pain to get them out so...... as I've said before......next time I would have a metal belly in this area.



Everything comes out so I can check every inch of the cables. They were excellent.



I decided to try to make a better hydraulic fitting mount this year. Before, I had them coming out of my brake cover panels. It was less than optimum and I was not very happy with it. If you order a kit from Javron now, and get the float kit option, he will have welded in mounting plates. When we did my kit, I/we, did not know where to locate them so I have been kinda doing "on site engineering" that was workable but not the best. Once again, this is the best I can do without ripping fabric off and welding in tabs. I think it will be better than what I had, but still not as good as the new stuff from Javron.



From the inside. The aluminum .040 plate was riveted to the c channel with cherrymax rivets then another plate was used to sandwich the fabric. I just used cheap pop rivets for that part so I could easily drill them out if and when necessary. The fittings are 1" apart (center of hole to center of hole) and that spacing seems to work well.



Close up shot from the inside. Folks - if you did not know this......the male part of the hydraulic fitting is VERY sensitive to scratches. Even a little nick will create a leak.......so......



You need a good supply of these parts. The blue ones are good to seal off the lines and I like them. The red plastic male works well but the red plastic female is pretty useless, except to prevent scratches. What happens is when installing the floats the lines will bang and scrape if you are not careful (and maybe even if you are) and again it only takes a very small scratch to allow a leak.



So what to do if you get a leak?......this is called a conical seal. It is a very thin, and soft, aluminum hat you can put on the male end of the fitting........



Like this.....and it will form fit and distort to seal the fitting and stop the leak. It is worth a try when replacing the fitting is too big of a Job. Here is a link to conical seals from Summit Racing Supply https://www.summitracing.com/search...tch&SortOrder=Ascending&keyword=conical seals


More to follow as I do this annual. But so far I am well pleased with things. Just normal wear and tear from an airplane with 1000 hours of hard use.


Hope this helps

Bill

Very nice, Bill! Nice hangar too! We missed going to Sandpoint last year.

sj

Many thanks Bill. I would have never thought of taking the tail completely off. Good suggestion, even though I’m never in the water . Maybe every other year. Thank you also for the Summit Racing link. I previously got on the male end with 7447 ScotchBrite and did a couple hundred round and round “sands” with my fingers until it was once again smooth. Now I can buy a supply of conical seals!

Eggs and "Elk Sausage" for breakfast. Thank you!!!.... Dan!
Life is good

Folks


Been a busy spring so I have been remiss in posting. Hope this helps. The annual went well. It took about 160 hours and there are things that still did not get done. I did get the ADSB installed. Since I go through Canada and spend a fair amount of time up there I got the 1090 freq set up verses the 978UAT freq. Now it looks like Canada might even go to "diversity" so I might have to upgrade in the future.
I am using a Trig T22 transponder that runs through the GRT EFIS display unit and a Safe-Fly WAAS enabled GPS module. That set up took several days to get installed and running. I had to call tech support to get a little help. I had serial port conflicts and could not figure it out. My issue was not in the manual so I was not going to ever get it without tech help. GRT was great as always. Seems to work like a charm now.

Overall I am quite pleased with the way things are holding up. Nothing unusual to report except........


This is what a normal flared fitting looks like.



This used to look like the picture above. Note, no flare left. This fitting was leaking (gee what a surprise). If you over tighten a flare fitting this is what eventually happens. Vibration and time will flatten it out. It does not take much pressure to get a good seal. Don't over tighten things.



This is what a normal, used, clean, plug looks like (I run automotive plugs)



This plug has lead deposits called "clinkers". The arrow points to little balls of lead that accumulate over time and cause fouling. You can dig them out (carefully) with a dental pick.


So.....this is how I rig my floats.....I'm sure I will be told that I'm doing it all wrong but here goes......



Get the floats on and the wires installed and at least firm enough to hold things in place. Without the wires the whole rig becomes a parallelogram and the airplane will list to one side and damage things. Now....run a string under the leading edge of the wing from one wingtip, over the top of the floats, to the other wingtip. I try to get it pretty much directly under the spar. Make sure the string is exactly parallel to the top of the floats. Don't let it touch the top of the floats because it will be hard to tell if it is being deflected. Measure REALLY carefully how high it sits above each float and make it EXACTLY the same from one float top to the other float top. You are dealing with a long lever arm, so to speak, so getting each distance above the float is critical. This establishes the angle of the floats from side to side. The fore/aft line is fixed by the rigging, sometimes referred to as the fish mouth angle.


Now you can measure from a common fixed point on each wing to the back of the respective float. By adjusting the wires you can move the floats left or right a little to get the floats to line up with the longitudinal axis of the fuselage. ie the floats are going the same direction as the fuselage. They should be pretty close to start with and you can't make say.....a 3" change..... but you can move it an inch or so....(at least on Wips) ....and you would like to get this within a 1/4 inch or less.



Next we will try to get the tops of the floats parallel to the lateral axis. ie they are lined up with the wing. Measure down from a common point on each wing, in this case where the spar connects to the last rib, to that string. Adjust the wires to get the same measurement. I shoot for 1/8" here. You will also have to check the longitudinal measurement (mentioned above) to make sure you don't get it out of whack while doing this one. By using the string you eliminate an un-level floor, or unequal tire pressure, etc.



Because of the threads being both left and right, and the fact that I am easily confused, I find it helpful to put a little tape with an arrow to tell me which way to turn to tighten while I am doing this.

Once you have the rigging set in this manner you can tweak things by adjusting the water rudders a little to finalize and perfect your in- flight handling. Fly it......adjust the water rudders to negate turning tendencies....fly it again.....adjust....fly ....adjust etc. You will then have a clue.....depending on how much offset they are......to the fact that you left them down in flight. The airplane will fly different from the up and down positions.....if you are sensitive enough to pay attention and also if the air is smooth enough. Obviously you won't notice in turbulence. If you get it right you will be able to fly hands off for long stretches. Note:......The airplane needs to fly straight before you put floats on. Get that rigging first. You must get it right, straight, rigged on wheels BEFORE you add the floats.



Bottom line.....it was a good annual and I am back in Alaska for the summer.....over Prince William Sound.



At the Big Shaheen Cabin......




No place else......going to be a great summer.....


Build that dream airplane.......you won't regret it.

Hope this helps

Bill

You are the most fastidious person I have ever known. Your attention to detail and pursuit of precision is remarkable. I’ll bet no one at Southwest ever worried when they gave you the keys to the big iron.

Your fabulous scenic photos look like they were taken by a professional with expensive equipment. Thanks for posting....everything!!!

Bill Rusk said:

View attachment 55576
Because of the threads being both left and right, and the fact that I am easily confused, I find it helpful to put a little tape with an arrow to tell me which way to turn to tighten while I am doing this.

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Bill,
It is easy to confuse this step. I place the right hand threads on the right side of the plane/floats and the left hand threads on the left. This keeps me from being confused with no need to write notes each time.

Excellent idea. I will incorporate that in the future. Thank you


Thank you for the kind words Paul. I have been very blessed


Bill

When we take floats off of a rigged plane we only loosen the wires on one side 5 to 8 turns and mark it. Makes it easy to reinstall in the spring, just tighten those wires back up the same number of turns

Glenn

Yeah, but he has a 5 gallon pail of marbles!

Paul Heinrich said:

You are the most fastidious person I have ever known. Your attention to detail and pursuit of precision is remarkable. I’ll bet no one at Southwest ever worried when they gave you the keys to the big iron.

Your fabulous scenic photos look like they were taken by a professional with expensive equipment. Thanks for posting....everything!!!

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Does anyone paint the aluminum spars and ribs?

Flyinwild said:

Does anyone paint the aluminum spars and ribs?

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It depends on the atmospheric conditions where you live. Lot's of salty seashore fog ... definitely. Keep it away from the seashore in a dry environment ...... optional.

skywagon8a said:

It depends on the atmospheric conditions where you live. Lot's of salty seashore fog ... definitely. Keep it away from the seashore in a dry environment ...... optional.

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For structure enclosed inside the wing, what's your opinion of etch/alodyne alone vs painted?

Web

Most Cubs spent a lot of their life tied down outside. Corrosion in the wings, though it does occur, has not been a significant problem. Is your aircraft going to be tied down outside in a corrosive environment (like the Gulf Coast), and do you expect to be alive in 50 years? For most of us the answers are “no” so I fall back on the keep it simple, light, and build for 90% rules.
Most of the experimental Cubs are always hangared and corrosion is just not going to be an issue in our lifetimes. If you live in the Bahamas and intend to fly it on floats in salt water all the time……well…..that changes EVERYTHING.


just my opinion

Bill

wireweinie said:

For structure enclosed inside the wing, what's your opinion of etch/alodyne alone vs painted?

Web

Click to expand...

Not my opinion but from my personal observation. Originally the Colonial Skimmer and Lake amphibians were alodined and zinc chromate primed with reasonably good corrosion resistance success. Along about the early to middle 60s they decided to just alodyne and skip the chromate primer. The engineering specs for alodyne suggested that alodyne alone was sufficient. I saw the inside of some wings of an alodyne only Lake which was only one year old, yet had been based in the very corrosive atmosphere of Teterboro New Jersey. These wings inside were covered with surface corrosion. Once this was brought to the attention of Aerofab (Lake manufacturer) they began the zinc chromate on top of alodyne process again.

Just etch/alodyne alone isn't as corrosion proof as the tests indicate.

I have etched, alodined and epoxy primed the spars and ribs. Piper did the same from at least the early to mid 70s on.

The flared AN fitting loosing it shape and going back to straight again does not make sense to me. I have seen over tighten flares and they just get bigger and thinner. The design of the ferrel should keep it from straightening out. I am not saying that tighter is better, but I don't think you would end up with the result shown if flared properly in the beginning.

It would be pretty easy to prove the premise so I will try it when I get a chance and post the results. Flare end of sample and then start to tighten more. Then taking it apart maybe every 1/4 turn until it fails and take a picture each time.

The oil return tubes on a Lycoming usually get reused and I have seen first hand over time how that flare becomes larger so I am curious to see what happens when a guy just keeps going to failure.

Thank you Greg. It didn’t make sense to me but I just couldn’t figure out anything else. I know darn well when I put that together it was a normal flare, so either I’m doing something wrong, or something weird is happening. So if anybody can shed more light on it I’m certainly willing to learn.

Bill

Hi Bill,
I am just getting started on a Javron wide super cub. I am enjoying all the posts and opinions this thread has generated. Did you put all of the weight information in a spreadsheet? Also did you make a parts list of your choices?