J-4 project-3.14159265359

A few days ago I just made it halfway through my 64th, I at least want this plane to outlast me. Not knowing what my end date is.

Yes the wheels were tight. The two phenolic wheels on the outside should have higher flanges, I did cut them deeper when I saw the flanges start to wrinkle. But it was either too little or too late. I have more material such that I could cut the rollers deeper still and go for it again. Gut feeling is the material is just to stiff for this simple method.
First step is to get time on the Pullmax and see what that does, if the dies will do inside work. I can make an inside die if needed.
Heck I might go downstairs and see if I can grind a groove in my shrinker dies to pass the flange through. I can learn to accept the rough finish since this gets a bottom cap anyway that can hide the tool marks.

Maybe, just maybe I am fretting something that is simple. I tried modifying my shrinker, that was a joke. it just took the bend out of the part, just the opposite of what was desired.
So after listening to an hour or two of the Allman Brothers and some newer Warren Haynes music my mind relaxed and got creative and thought of the simple things.

I turned the working side of the rollers around on the mill, loaded the strip and started working the high spots with the rollers supporting the curve. This is working.


Far from finished but it is something I can do in house.

I needed to confirm just how wide the firewall needs to be since when I clamped the fiberglass rod to the side of the fuselage so I could confirm the arc the door will get built to since I am going to start forming those parts. Something did not look right, I either made the front cabin structure taper down to much at the base of the windshield or my aluminum proof of concept firewall was too wide. I had not brought the camera down for this session.
So, bolt on the engine mount, get some mount bushings at hand and bring the motor over.


Turns out the FW aft of the cylinders can be 3" narrower than I made the aluminum template. Dang glad I did not go straight to Titanium with this.
Heck it feels nice to hang an engine for the first time and measure things to compare to my drawings. All looks sweet although I do not know where the error in the FW template came from.
Definitely going to make use of the swing out mount with the engine moved back this far.

The FW does get boxed in to allow room for legacy componants to be utilized on the engine.

Looking things over while the engine is hanging in place, looks like I missed giving myself clearance if I want a rear mount Prop governor. Oh well, could always change it but probably not going to.

CharlieN said:

Looking things over while the engine is hanging in place, looks like I missed giving myself clearance if I want a rear mount Prop governor. Oh well, could always change it but probably not going to.
View attachment 45881 View attachment 45882

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Maybe a “pocket” in the firewall? My plane has one for my oil filter.

I will be building a 2½ or 3" deep pocket in the FW, but what I did here was to place both the cross tube on the mount as well as the X brace in the FW structure right where the Governor goes.

I have not mounted either Mag but they look like there is no restriction for them.

More than likely I will go with an electric prop from Airmaster.

CharlieN said:

I will be building a 2½ or 3" deep pocket in the FW, but what I did here was to place both the cross tube on the mount as well as the X brace in the FW structure right where the Governor goes.

I have not mounted either Mag but they look like there is no restriction for them.

More than likely I will go with an electric prop from Airmaster.

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Ah, gotcha. I didn’t realize there was a tube in the way!

It is just an irritant at this point, I think back I was considering making the X brace tubes asymmetric to relieve the interference but I expect it was just not worth it. Now if an engine-prop package comes my was for decent money I will gladly rework a few tubes. I am not expecting that to happen.

Three little tubes, well control sticks that is, The lower being from my original J4, the aluminum ones are for my plane. The center one came out sweet. I will more than likely scrap the upper since I did not have the sleeve in the die set right and the tube deformed early in the bend.

The knobs are 3D printed and contain both a trim switch and a PTT. The yellow parts are switch retainers that fit up inside the knob.
The grip is printed in flex foam, they feel great and I do not want to fit them onto the sticks till the time is right, I do not think I will get them off easily.



The dimensional differences between original and mine are two things, One my control assembly is considerable more compact resulting in the system all being aft of the carry through tube at the lift struts.
Two, my cabin is 7" lower top to bottom.

Charlie, Is that extra length just slid on to increase the wall thickness in the lower end?
This is reminding me of long ago in the early 60s (1963?) at GBR. There were a half a dozen 450 Stearmans which were spraying for Gypsy Moths just over the border in New York. One of them didn't return. I went with the NTSB to inspect the wreckage and found that the aluminum stick had had a V cut out of it, bent and welded back together in order for the stick to clear the hopper. The weld had peeled back rendering the stick useless preventing the elevators from raising the nose. The trees won. The pilot did not.

I get very nervous if I see a weld across a stick without adequate reinforcement. If you are entertaining welding there, do a bunch of rosettes instead of along that joint. I have never forgotten that day. In fact I dreamed that it was going to happen a couple of hours before it did. That part is really scary.

Those days suck, the premonitions are with us forever.
Yes they are a doubler. I originally planned to weld around the top but there are times something tells me to not do it. Obviously 6061 goes soft with the weld. I do not trust home heat treating and have no local resources here to properly do so. I might glue these.
These do get another lower tube added inside the very bottom. It will be there to simply index the stick in place with a pip pin retaining them. Left side might be through bolted while the right has clips on the floor to stow while removed.
That third layer of tube will be rosette welded way down low well beyond any stressed region.

This image shows what the stick fit into. The open hole is for the pin. Top of assembly gets a slit in it allowing the red bicycle seat clamp to snug things up.
The sticks will have a hole drilled above that clamp where the wires pass through which plug into a 6 terminal quick connect.

I like the glue idea as all it will be doing is to take up residual slop.

The stick for the EAB -12 I'm working on will be 4130. Not a place to scrimp, in my opinion. Not saying CharlieN is scrimping - looks like he's given it a lot of thought. But, even very thin wall 4130 will bend, not just break off .......

Along those lines, here's a story that ended up fine, but might not have - - A crappy weather day in Juneau, and a buddy and I were staying in the pattern in his -12. He was in front. Well, we were horsing around, doing stalls and who knows what else, cuz nobody else was out there. The tower inquired whether we were a student pilot; and good ol' Al responds naah, we're just bored. Well, I was flying from the back. We were on short final (keep in mind here that we had been horsing around so unusual attitudes were usual) and the darn stick came out of its socket. I'm yelling hey Al, your controls, but he couldn't hear any better then than I can now (no intercom in those days). No response. So I frantically tried to put my stick back in place and succeeded at the last moment.

Yeah, having an effective control stick is kinda nice.

I will stay with aluminum on these as all my builds before have used. The doubler reduces most all chance of material failure. This plane also utilizes ball bearings on all control pivots which is not a first for me. The reduction of friction build up under higher loadings reduces forces within the system.
Personally thin 4130 needs to be sleeved at stressed areas as well and can be seen in my fuselage and every stressed part I build. Things like my longerons vary from .093 wall down to .028 in areas.

Now I have two good control sticks, the upper one I scrapped since my stepped die was not set up right.
The two good sticks have a different bend deliberately since I do not really know which will be more comfortable to me. I have little to no side flex in my right hand and not knowing which side of this plane I will prefer to fly from I want the choice of control shapes to pick from.

Almost but not quite. I am working on the front of the lower door frames, these are being made from ¾-.035 mild square tube.
I almost got a decent bend, it does match the vertical tube it needs to hide behind. But it has a bit more tool marks than I care for. But maybe I am being overly picky.


I am thinking I will build a new die for my bender that can have elements changed to allow better support for small square and rectangular tube.
The bottom of the lower door I would like to make from a very thin 10X20mm rectangular tube which buckles to damn easily on previous attempts. I just might be able to win if I commit to some new dies.

It is interesting sitting here at my computer, closing out the night after another session doing design revisions. This time on the trim jackscrew and related brackets and mountings.
The mounting points are fixed being they are all completed structure on the fuselage.
The jackscrew itself is also fixed in that it is an industrial ball screw with a coupled electric motor and worm drive. The interface to the horizontal Was drawn and machined a few years ago.
But the interesting thing about drawing on CAD is this is the 14th of 15th redesign of the assembly. Might actually be well more than 40 since each redesign is a renamed drawing and once I have a half dozen near current versions they get moved to an old drawing storage file. There are many of those files since they pertain to the many generations this project is evolving through.

It is getting simpler and lighter, everything, the plane as a whole, not just the trim jack. And this is not a simple plane, nothing I have built has been.

In thing I am realizing with this build, my timesheet is all but bogus at this point. I am not logging my time at the computer and I expect I have well more than 4 times the hours drawing than building. Probably well more than that. I truly do like to make changes to a drawing rather than scrap parts. Especially if the part was just not designed as well as it needed to be.

I think back to when I started Engineering drawing followed with Architectural training. I got bored with Architecture early on, stupid mistake, well I don't count them any more either.
Soon I bought an 8' drafting table and a Vemco V track Drafting machine. I marvel when I sit at it still.
Built some neat stuff that was drawn on that. No where near as many revisions in those days. Heck the revisions were done in, wood, composites and metal. Rare the revision ever got back to paper. I think of the 3 houses, two boats. Motorcycle frames and both tube frame and monocoque chassis race cars that came off my drafting tables.

But those days we did not need to convert the drawing to an STL file and send it to a machine that spits out parts.
No wonder I have never had any TV service. I do own a TV, heck it even claims to be 3D not that my drawings look to be when viewed on it.
I can view a wing rib in full size on it.
Well just wandering about in words here, 4AM will be around soon enough and I will be back here to look at this trim system with a fresh mind, again.
OK how many read all the way though that?
I am not sure I have.

CharlieN said:

OK how many read all the way though that?
I am not sure I have.

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LOL. I read through it all. I've had similar thoughts and experiences except I've never really gotten into designing on a computer. I have SolidWorks from my EAA membership, but I haven't done more than install it.

But I do have an 8' drafting table. No TV. I quit watching when Gunsmoke went off the air.

Nice to hear of other large drfting tables out there,
Solidworks is interesting to me. I also have the EAA gifted version. I am still most productive on an antique version of Autocad, as in the 1997 version E14. I still prefer R12 DOS but never could draw surfaces well on it. The change that R13 &14 brought were great. Any newer version is just fat. Yes they dimension easier but they suck to draw on.
This past summer at OSH I got a few hours of training with Solidworks. I finally recognize the similarity in process between ACAD and SW. They really are similar in approach, just done in a different language.
After the first hour one rep recognized the pattern I worked in and marked me as an ACAD user, which 8 out of 10 of us were.
I pulled out my tablet which has plenty of screenshots and photos of this build, many of which are in this thread.
His comment when looking at the engine cowl and other surface work, Oh you use Solidworks.
Me, no this is Acad R14.
Him, you can not draw that in ACAD.
Me, I wish someone told me that before I drew it.
He showed me steps to guide he to learn the different Language to come up to speed in SW.
The problem I have though is the rather expensive new Dell with it's 4K display and Win 10 OS.
The OS will not let me save files and drawings, tools where SW requires them. I dug into the background of Win 10 and was close to making it work well when my computer guru who is down in Tx says "Oh you need the latest upgrade,it is much better" Well it F'ing wiped all my work to turn off the automated crap. To me a computer is a tool, not a toy. Win 10 is for children, it is not a work tool if you can not place a file where it needs to be.

Gee, after my long post about drawing which brought up the subject of updating drawings.
As I am still doing detail design on the horizontal trim system. What I was drawing was not fitting the fuselage.
I go down in the shop and measure, the 34th time, check the part drawing. Heck each part is a layered import of many other parts. But it does not fit the main fuselage, "drawing" Well, WTF, I never updated the main fuselage drawing aft building the fuselage and installing many tabs and brackets.
The biggest issue are the brackets that the tailwheel and trim jack mount to was built to what was needed but never had a specific drawing for it.
Oh well, a long session last night making revisions and things fit on the drawings now.
Turns out the horizontal stabilizer will have a longer cord between front a rear spars than the drawings were trying to guide me.

I can not even imagine managing 100+ draftsmen all on separate tables back in the 30s drawing a B-17 or a Lancaster. I can see why they drank.

Hah! Now you know why we as mechanics are always complaining about why the engineers did something a certain way! And as you pointed out, they didn't even have the advantages of computers as today's engineers have in their quiver.

I reminisce back, way back for me, 50 years ago I built the little Glen L 8' hydroplane that Popular Mechanics magazine introduced many people two. Fair bit of curved plywood work involve that if those simple plans had any issues to them I do not recall them being an issue. That project started my transition from art to engineering. I also started volunteering at motorsports events and my first flight lessons, allot of growing up that summer for a 14 Yo.
It was not real long that I was building things from my own drawings but they were so damn simple back then. Or at least I think they were simple.
Thinking back to '87 when I did my first Cad drawings so I could print multiple wing templates so my employees could make multiple Waco ribs at the same time, even that seems like it was simple.
Yes I have drawn a few "difficult to build" structures over the years, but they have all turned out well.
Heck I still would like to go back and pull out my massive paper drawing files for a high performance two seater that I designed to utilize a C-402 firewall forward assembly. I know I can not fund the project now, I could back then but never went there. Humm, never know.

Hmmm? I wonder how that little Glenn L hydro would work with a 5 hp Tohatsu outboard?
This one?

It wont be very invigorating. I doubt you will be able to get the hull to fly but then the 5hp on that Tohatsu might be pretty close the 14Hp the boat was intended for. I ended up with a Mercury Mark 20H on mine that my dad brought home from the power station, and I do not think it was stock.
In time with guidance from a retired racer I learned how to properly rig the hull with it eventually running in the low 60s, according to a policeman's radar. That was damn cool for a kid that was yet to get my drivers license. But heck I had soloed a plane before I could legally drive a car as well. It was allot of learning for me and my few friends that ran the boat.
With that picture above I doubt you cold get the boat on plane when sitting with a race prop on it. It took allot of body english to get mine out of the hole. You had to crawl out on the foredeck to get it to climb over the wave it generated, but when it came over you never needed to climb back in, it put you there in a hurry.

I built mine from whatever wood I could coax my parents to bring home from the lumber yard. It never got properly protected or if I had it was just not maintained and rotted away over the decades. I do still have the CW race throttle and steering rigging in storage here. But with my knees as they are now I would never get in a fast kneeler at this point. A high performance canoe is enough for my bad leg now and my current boats which are faster than that one I started with are good enough. They keep my attention.

19 more fresh drawings of my horizontal trim mechanism, back on Monday I ordered some material which should have been here yesterday, and still not this evening but Fed Ex no longer delivers one day packages in, well one day. Seems to take 3 to 4 days now. Sure get your moneys worth these days.

But I have started building the trim system. If I am a good boy I will even bring my camera into the shop tomorrow and log the process.

I did order in a new to me motor for this so I can not say I am done with design work.

With many mornings and evenings drawing and redrawing the trim jack system I am moving forward with a build. Which of course means I will think of a simpler or lighter way to do this.
Here is a screen print of where I am going,


A few of the parts being roughed out, These are being made from rectangular tube simply because they are essentially self jigging and although not the lightest way to go they have plenty of reserve strength.


And the lower mounting points with the final jigging before final welding.

Well, both bottles of Argon are empty so I am done welding till next week. I am happy with progress on the trim system. There will be little tweaks to the design as I move forward but it is time to move onto other tasks, like haul in another trailer load of wood for the boiler and prepare for the house to fill with people for our annual end of year party.

Trimming the lower section of the trim mounts.


Lower section of trim on it's jig.

Wow, cool. 50,000 views in 3½ years for my humble little project. Thank you everyone who has shared interest in my design & build.

CharlieN said:

Wow, cool. 50,000 views in 3½ years for my humble little project. Thank you everyone who has shared interest in my design & build.

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Thank you for posting! I always get ideas looking over what you are doing. Steady as she goes!

When I first wrote my note I thought I have been posting here for 2 ½ years. Humm time flies when your having fun.
Vic I enjoy your thread since you are not afraid to buy a tool you need to get the job done right. That is enjoyable to watch. It shows the growth of a man and his project rather than the just get it done even if it is one step from scrap that I see online. Granted I do not see much of that here but it can be seen aplenty on a few homebuilt forums.
This forum exhibits a much higher professionalism than the online average.

CharlieN said:

Vic I enjoy your thread since you are not afraid to buy a tool you need to get the job done right. That is enjoyable to watch. It shows the growth of a man and his project rather than the just get it done even if it is one step from scrap that I see online. Granted I do not see much of that here but it can be seen aplenty on a few homebuilt forums.
This forum exhibits a much higher professionalism than the online average.

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Thanks Charlie. That's the whole point of Experimental, right? At least for me, the project is so I can learn and grow in knowledge. Certainly not for me to show off. If I get a decent shop out of it, so much the better!

I agree. I'm continually blown away by the knowledge and skill here. It encourages me to reach higher.

Vic