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J-4 project-3.14159265359

Back in the late 60's and early 70's when I was starting out with aircraft at 4B9 Simsbury CT there was a pile Sea Bees along one border of the field. Guess a previous "elder" mechanic as in Mr Myers had a soft spot in his heart and built a number of them and of course many pilots kept rolling them up on him.
Interesting and cool planes, I was at the time not aware of the Twin Bees but that extra power must have been a wonderful thing.
 
The twin was basically the same as the single with increased wing span of 68", fuselage stretch of 36", each flap lengthened 4 feet with an IO-360 B1D on each wing for which we received the Type Certificate in 1965. It changed a streamlined anvil to a Helio beater. An amazing transformation. The first few were made at the Canton Mass airport before moving to Norwood.
 
The twin was basically the same as the single with increased wing span of 68", fuselage stretch of 36", each flap lengthened 4 feet with an IO-360 B1D on each wing for which we received the Type Certificate in 1965. It changed a streamlined anvil to a Helio beater. An amazing transformation. The first few were made at the Canton Mass airport before moving to Norwood.
Pete,
My Dad bought an old standard "Bee" back in 71 from an old fella up in Shin Pd named Arthur Augustine. It had the
Miller wing extension on it. Very underpowered outfit. But after watching you at Greenville in the late 70's ........what an eye opener! [emoji33] A few years later while working at Kenmore I saw one with the Helio engine, GO480 with 3 blade prop. I fueled him up and as he left a Kenmore 185 on 2960's departed and I noted where he broke water, the SeaBee took of right behind him and got off in the same spot.........looked like the ROC was 3X what it was with
the old Franklin.
Charlie you are doing a great job on this Cub Coupe, keep up the great work. Interesting thread.[emoji6]

Sent from my LM-X210 using SuperCub.Org mobile app
 
I have just passed 30hrs in welding on the fuselage, not even to the point of mounting the frame onto the rotisserie.
I think I will machine parts for the elevators and rudder for awhile.
 
More and more welding, the frame is Starboard side down and will be for another day or so. Crouching on the floor inside the frame with my knee on the pedal limits my dutycycle a bit. But it's moving forward.
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One of my favorite welding toys is my Miller wireless pedal. It seems frivolous until you get spoiled not having to fool with that cord. I've worked it with my knee, my elbow etc. As you know, fuselage welding is for contortionists even with a rotisserie.
 
I have not worked with the wireless, it would be nice to have one less cable in the way. I have yet to dig my rotisserie out of the snow, I can see the top of them now, still a few feet of snow to melt away since they got left outdoors this year.

One thing I am thinking of changing is parking the Syncrowave, I have a Thermal arc Inverter Tig with an ultra flex cable. I normally do not do much with aircooled torches but I am currently using a CK 20 torch that has the 3 hoses combined, those hoses are heavy and not what I would consider very flexible. I do not have much use of my right thumb and working on the inner structure is a contortionist act. Plus the Thermal arc is just about silent as well. Not like we need allot of cooling on this type of work.
 
Unfortunately very little has been done, some ugly aspects of life have been eating away at me.

Last night though I did machine the pivot for the elevator bellcrank that installs under the floor aft of the seats. First part I have made in months.


I have not been able to relax enough to weld thin tube so I felt it was best to walk away. Frustrating when one's 64th birthday goes by and you know you are not moving forward on a long term project.

Closeup of the pivot pin slid in place. Fuse is hanging on it's side.
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The split in the tube was done so I could install an internal doubler since this is an .028 wall tube.
 

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so for the elevator it will be a solid linkage with no cables?

Push-pull under floor to a horizontally mounted bellcrank under baggage area. Cables run back half way under floor allowing for long baggage space, then rise as needed to get to elevator.
The control sticks and all bellcranks mount on ball bearings and cable ends utilize aviation REP bearings so there is very little chance of friction.
The control surfaces themselves are also hinged on ball bearings.
 
The control sticks and all bellcranks mount on ball bearings and cable ends utilize aviation REP bearings so there is very little chance of friction.
The control surfaces themselves are also hinged on ball bearings.

Looks good Charlie--

I'm really interested in these various bearings. I searched REP bearings and couldn't find anything. And I'm wondering how the control surface bearings mount. Last I recall (long ago--I know) you were talking strap hinges.

Vic
 
Yes my original intention was to utilize strap hinges. I made the spars for the elevator in stainless to reduce the chance of corrosion within the hinge area. And with the greater selection of low friction engineering plastics as well as the ability now to 3D print extremely complex shapes strap hinges are of great interest.

But I also like ball bearings, no stiction, yup a tough word for me to spell but low static friction, the break free force in low movement pivots.
I had already designed ball bearings in the early parts I made. I have not taken any pictures of the bearings installed, primarily since they go against the grain in some circles, I will get some shots.

What I do have,
Control stick pivot, there are bearings inside the relay rod as well.
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I will take pictures of the mounts for the torque tube since they have bearings inserted as well.

Bottom of rudder, the control horn has two bearings inserted, these are 3/8 ID flanged bearings, the lower sets over a stainless pivot pin, the upper is primarily there for support but prevents the rudder from lifting off the upper or lower pivot pins.
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The control cables will have threaded ends swaged in place that will be fitted into FAFNIR REP3 Bearings. There are many different sizes available, I am now over $1500 of these bearings in this project alone. The elevator horns to the left have these bearings in place.
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Thank you Gordon for that link above.

My control torque tube rides on these these thin wall bearings, they are available in assorted sizes.

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I am getting some welding done once again. I am welding inside structure in the aft section of the fuselage. This used to be pretty easy when I was young and did not need glasses to focus on the arc. Frustrating part is depending on the reader I wear I can get a near perfect view of the weld, but only within a few inch depth of view.
Trying to get one's helmeted head partially withing the structure allowing for the proper viewing angle and distance while allowing both arms to be positioned as needed with the precision to weld at the very low power that .028 and .035 wall tube requires.

Dang this is kind of slow going one might say.
 
I am getting some welding done once again. I am welding inside structure in the aft section of the fuselage. This used to be pretty easy when I was young and did not need glasses to focus on the arc. Frustrating part is depending on the reader I wear I can get a near perfect view of the weld, but only within a few inch depth of view.Trying to get one's helmeted head partially withing the structure allowing for the proper viewing angle and distance while allowing both arms to be positioned as needed with the precision to weld at the very low power that .028 and .035 wall tube requires.Dang this is kind of slow going one might say.
I feel for you, Charlie! I'm using gas, but I have three different drug-store readers for whichever task is at hand. I'm using a face shield after a few times of bumping my cheek with a hot rod tip while contorting through the airframe. It also makes it a little easier to change glasses.
 
Thinking about the glasses, I stack the readers :oops: Kind of sounds stupid but I tend to wear a pair of very large lens general distance glass that works well at 3 to 8 feet or so, about a 1.5 for me. These would be considered the safety glasses. Then I slip closeup glasses under these, under as in from the top between the general ones and my eyes. This combination my focal length is 8" to a foot or so.

But yes, when you blast a hole through a tube or burn back an edge, it does not matter what torch was in your hand, ya still got to fix it.

I think back, I have not done much torch work in recent years but I have some to do, my go to torch is a set of Purox 200 "aircraft" torches my dad brought home from work when I turned 14. They still run well now fifty years after I got them used.

There are times the softer flame is easier to work than the higher energy of the TIG rig.
 
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Interesting, a friend of mine lives 6 miles from his listed location. There is another rafter rat hanging on Bob's Island near here as well.
In many ways, for the money it would not be worth my time to finish the rebuild of my original one.

But scrolling down that FB listing the Swift at $26K caught my eye.
 
As I am picking away at the small hard to get to welds, when I step back I keep getting an illusion something just Ain't right.

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My mind playing tricks on me since the fuse is hanging upside down from the ceiling, but the curve of the longerons looks like it is upright, but missing the vertical spar.
 

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Charlie, Looking forward there is a horizontal tube which ends. It looks like a mid partial longeron and is the same on both sides. Above that end cutoff there is a vertical which goes to the bottom longeron, top of picture. Why is one of these verticals bent in the middle and the opposite one not bent?
 
Good eye Pete,
Not sure I really like this mid longeron but I wanted substantial shoulder height structure to mount the shoulder belts too. The structure adds allot of torsional strength which just may not be needed. I am used to the cars I have built where each one is stiffer than 10,000 Ft-Lbs in torsion. The plane has no need to be but it is hard for me to back down.
I have yet to measure this frame in torsion or bending since there are a number of critical diagonals in the last bay near the tail that are not installed yet.

This mid structure also imitates the original J-4 shelf behind the seats.

The asymmetry you see is where on one side is a lower baggage door with upper on the other side.
The bent tubes are where a mid stringer will terminate while eliminating the need for additional tin work around the door openings.
Intention is the fabric will directly wrap the tubes around openings with either V or D seal gaskets on the door edges. Simple with fewer parts and especially greatly reduced cavities for rust to start.
 
Charlie

Dunno if you have ever seen these or not but great for gas welding, you put whatever "cheater" lens in that you need and don't have to stack your glasses.

Wouldn't help RV from poking himself with a hot filler rod tho!


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https://www.ebay.com/itm/MAGWELD-IR...m=372474586722&_trksid=p2047675.c100010.m2109


A friend turned me on to them years ago................ work great. I still have to use 2.5 cheaters for tig work. The glasses seem to work better for me than the inserts for the helmet
 

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Wouldn't help RV from poking himself with a hot filler rod tho!

There is no help for me. If I weld long enough my hand goes numb and I can't feel what direction the rod is heading after I stop. People at work have started looking for the latest interesting brand marks on me. The face shield helps a lot!
 
Those glasses look allot better than the glasses/goggles of the past. I have had clear wrap arounds that technically had correction but either I did not know how much correction I needed at the time since I grew up as a hawkeye, the transition to lenses took me some time.
And I have burnt my cheek more than once.
Heck a few decades ago I was doing some torchwork, hot summer day wearing shorts. I was one of those muscle bound weight lifter types that wore short shorts.
I fumbled and dropped the torch, tip went down right into my inner leg, that mark is still there.
Vic, I now have a new to me pinched nerve in my neck, makes my left arm and hand go numb. I have motor control but the full arm tingles. Not every weld but is a half dozen times a day. I am going to have to give in and go for PT.
 
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