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Building an Experimental PA11

J-3 was built under the CAR 4 regulations. Not sure if CAR 3 is applicable. .
Understood, I didn't have Part 4 in front of me. However I doubt there is any or much difference in this requirement.
Supercrow is correct on your other question. Some people seem to think they can get away with that thought process, they are wrong. They just haven't been caught.
 
It would be nice if some of that type of thing could be done, and no harm in most cases, but it would be most difficult to do with a straight face.

It can be done, either as a field approval, or as a DER approval as a deviation to the STC. In any case, each STCis only applicable to the specific model or models if an AML STC, and in some cases, specific serials within a model.

You will find a lot of STCs for J3C-65, but they can’t be used (by themselves) for J3L or J3F series airplanes since they aren’t listed on the STC.

All that said, the topic of this thread is building an experimental PA-11, and in that case, since it isn’t a Standard certificate the OP doesn’t need to concern himself with compliance with STCs and such.


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I had hoped the new proposed weight increase for Light Sport would have become effective by the time I certified this airplane since the plans allow 1400lb gross weight, but as it stands, I guess I should probably certify at 1320. I'm a Private Pilot, and Basic Med is still a thing..... but I do have a CFI-SP, so if I wanted to instruct my Children (who are now grown), or grandchildren down the road should they become interested, I could....It's too bad though....that extra little bit would be nice....I mean, I'll never fly it at 1400lbs....no way ahem. If I really believed it would happen....I might go ahead and give myself that extra 80lbs useful, but I won't bank on the FAA getting it done.
https://generalaviationnews.com/2020/09/03/the-latest-on-the-faas-proposed-changes-to-lsa/

That being said, I got some usefull stuff done today...I installed a 3 position switch for my master, off/batt/alt, all in one nice little toggle switch that cost less than $5 bucks....it's an idea I got from a Kitplanes article....I like it. I drilled out the .125 copper buss bar for my breakers and the darn screws are too short....typical, I should have found some .0625 thick bar i guess. New scews coming up. I fooled around with that corrugated platic I bought for the interior...I think it's going to work out nicely. I glued some fabric on a piece and really kicked it around....pretty tuff, and very light. I only have the one fuel line feft to make (the flex line from the steve's gascolator to the carb)....do you guys put fire sleeve on?? I didn't on my J3...just wondering if it's worth grabbing some? I put a rubber windshield strip on (I read a bunch of threads on here) and chose to do it that way, but I have a rubber L shaped strip rivited all along the inside with the rubber channel like a Zenith uses around the bottom of the windshield. I saw a few that didn't do the inside L piece but I like having that contained all the way around, If later I don't like it, I'll put the traditional strip in there (or I'll play with fiberglass and lay one up)...I think it will be fine though. I have surplus Piper Colt fuel tanks that are in nice shape, but they need new gaskets for the fuel senders...I ordered them up today and was wondering if I should do some testing on the senders....are these a common problem area? I should hook them up and see if they move with the darn float, and make sure the float floats....I've got quite a bit of time in a colt and don't remember my buddy having trouble with his in the last 30+ years....just wondering? A leak would be crappy. As I said before, I have the headerless system so ports on front and back of tanks....I will leak check all of this, and do FAA flow test which I'm sure will be fine....Thanks for the info on the caps....the pressure one's I was going to get were $45 each..the plain vented caps are about $10....good stuff.
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Senders can be checked with an ohmmeter. If you have brass floats, dunk them in fuel for a few days, then shake them to see if they slosh. If they do, they leak.

Web
 
I had hoped the new proposed weight increase for Light Sport would have become effective by the time I certified this airplane since the plans allow 1400lb gross weight, but as it stands, I guess I should probably certify at 1320. I'm a Private Pilot, and Basic Med is still a thing..... but I do have a CFI-SP, so if I wanted to instruct my Children (who are now grown), or grandchildren down the road should they become interested, I could....It's too bad though....that extra little bit would be nice....I mean, I'll never fly it at 1400lbs....no way ahem. If I really believed it would happen....I might go ahead and give myself that extra 80lbs useful, but I won't bank on the FAA getting it done.
https://generalaviationnews.com/2020/09/03/the-latest-on-the-faas-proposed-changes-to-lsa/

That being said, I got some usefull stuff done today...I installed a 3 position switch for my master, off/batt/alt, all in one nice little toggle switch that cost less than $5 bucks....it's an idea I got from a Kitplanes article....I like it. I drilled out the .125 copper buss bar for my breakers and the darn screws are too short....typical, I should have found some .0625 thick bar i guess. New scews coming up. I fooled around with that corrugated platic I bought for the interior...I think it's going to work out nicely. I glued some fabric on a piece and really kicked it around....pretty tuff, and very light. I only have the one fuel line feft to make (the flex line from the steve's gascolator to the carb)....do you guys put fire sleeve on?? I didn't on my J3...just wondering if it's worth grabbing some? I put a rubber windshield strip on (I read a bunch of threads on here) and chose to do it that way, but I have a rubber L shaped strip rivited all along the inside with the rubber channel like a Zenith uses around the bottom of the windshield. I saw a few that didn't do the inside L piece but I like having that contained all the way around, If later I don't like it, I'll put the traditional strip in there (or I'll play with fiberglass and lay one up)...I think it will be fine though. I have surplus Piper Colt fuel tanks that are in nice shape, but they need new gaskets for the fuel senders...I ordered them up today and was wondering if I should do some testing on the senders....are these a common problem area? I should hook them up and see if they move with the darn float, and make sure the float floats....I've got quite a bit of time in a colt and don't remember my buddy having trouble with his in the last 30+ years....just wondering? A leak would be crappy. As I said before, I have the headerless system so ports on front and back of tanks....I will leak check all of this, and do FAA flow test which I'm sure will be fine....Thanks for the info on the caps....the pressure one's I was going to get were $45 each..the plain vented caps are about $10....good stuff.
View attachment 53907

You are likely looking at at least another 5 years before they change the Sport Pilot rules. It hasn’t been out as an NPRM yet, and they typically take about 3 years to adjudicate the comments.


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I always wondered what the term “Pay the Piper” Meant...Wife walks into the hanger while I’m up on a ladder wiring lights as I install new ceiling metal....she walks around the giant pile of insulation and says: “You’ve been buying lots of airplane parts and hangar material lately”...I look down at her thinking...uh oh. Her: “I think you should come down and take me furniture shopping this afternoon”.....Me: “Yes Dear” gotta pay the Piper. Lol
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I could have bought a lot of airplane parts with what we ended up spending. Cheap in the long run though.
 

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When my wife got into sewing and quilting, I exhibited some surprise when her new machine rang in at around $4,000. A few months later, she mentioned she was going to buy a surging machine. When I asked how much those were, she looked at me and said “well, they’re expensive, but not AIRPLANE expensive”... I don’t ask anymore.......
 
This year after a friend let me take my wife for a ride in a cub on floats she said you know, I think we need anfibs. Yes dear. Happy wife happy life right?


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I had hoped the new proposed weight increase for Light Sport would have become effective by the time I certified this airplane since the plans allow 1400lb gross weight, but as it stands, I guess I should probably certify at 1320. I'm a Private Pilot, and Basic Med is still a thing..... but I do have a CFI-SP, so if I wanted to instruct my Children (who are now grown), or grandchildren down the road should they become interested, I could....It's too bad though....that extra little bit would be nice....

Dan,

You could do it at 1320 now, and will always have the option of raising the gross weight later if you so choose. Your operating limitations will include a provision for incorporating a "major change". A gross weight increase would constitute a major change and would involve some additional flight testing, but it can be done. So if they up the gross weight for sport-pilot operations at some time in the future, or if you just want to go BasicMed and forget sport pilot, you will always have that option. We will discuss this when we do your inspection.
 
I have read many posts on upside down or right side up mounting of master and starter relays (solenoids) and I have a couple of additional questions...one is, can the relays be mounted sideways without performance issues? And what are everyone’s thoughts on mounting relays to the firewall (engine side)vs mounting inside? My battery is mounted inside on the firewall....don’t worry, I have a plan for my cabin heat which will route it such that it doesn’t blow right on my battery. ( work in progress).
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I always mount master and starter relays straight up or straight down. I don't have engineering data to back it up, but it seems to me that a round plunger in a round bore should work better that way than scraping back and forth on its side.
When I do a rewire on Cub types, I like to place the start relay in a bracket mounted near the cockpit side of the firewall. It's not an item that gets replaced often and I like it protected from the weather and engine heat. And ALWAYS place the master relay as close to the battery positive post as physically possible. Keep that hot lead short.
Also, place a spike diode across the coil connections on each relay installed. This will help protect your electronics.

Web
 
Ok, I already did put in the diodes...I was just figuring out final placement of these relays. It sounds like you prefer inside the cockpit... makes sense. Now, I have my master relay configured so my master switch goes to ground an the relay picks up, my mag/start key switch switches S to 12v (bat) when turned to the start position...white stripe on diode toward 12v source.
 
The only rationale I've heard for mounting relays "sideways" is in aerobatic aircraft, where high negative-G maneuvers could cause the "plunger" to close at a very inopportune time. For the "rest of us" I suspect we'll never pull enough Gs to make a difference. BWTHDIK?
 
I have read many posts on upside down or right side up mounting of master and starter relays (solenoids) and I have a couple of additional questions...one is, can the relays be mounted sideways without performance issues? And what are everyone’s thoughts on mounting relays to the firewall (engine side)vs mounting inside? My battery is mounted inside on the firewall....don’t worry, I have a plan for my cabin heat which will route it such that it doesn’t blow right on my battery. ( work in progress).
View attachment 54696

Your master and starter relays should be as close to the battery as possible. The wire from the battery to the master is unprotected, and so is the wire from the master to starter relay. You want unprotected (especially high current unprotected) wires to be as short as possible, preferably with no bulkhead penetrations. The shorter they are, the less chance of insulation fraying and the wire shorting out.


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I’ll mount my relays right above and to the right of my battery. On another note...Wayne from Southern Aero finished up my strut fittings...once they arrive with the streamlined aluminum material He’s sending with it, I can build my aluminum lift struts. He does nice work.
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I have been working hard at finishing the hangar Too, I got the ceiling up, lights in, and blown in insulation done too.
time to focus on finishing the Cub!
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getting some wiring done...should be close by the end of the week. Planning to build new aluminum lift struts this weekend.
 

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I’ll mount my relays right above and to the right of my battery. On another note...Wayne from Southern Aero finished up my strut fittings...once they arrive with the streamlined aluminum material He’s sending with it, I can build my aluminum lift struts. He does nice work.
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I can't wait to see how these go together for you.
 
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The front struts are together..I have the rear struts drilled and have only to drill the eye bolt holes at the jury strut locations...I’m doing this instead of strut clamps.
 

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....and have only to drill the eye bolt holes at the jury strut locations...I’m doing this instead of strut clamps.
I have been made aware recently of an issue with using eye bolts for the jury struts rather than the old Piper clamps. It seems that removing the flexibility of the clamps causes the rivets which hold the upper jury strut fitting to the wing spar to loosen. Will you be looking at those rivets during every preflight? Then if you beef up the rivet attachment with bolts, the eye bolts break in the strut.

Airplanes flex in many places where most of us don't think they flex. When one makes an "improvement" which stiffens that flexibility location, it is not unusual for that "improvement" to fail. By removing that flex location you are stiffening the whole flexible wing/strut assembly so that the flexing is concentrated on your eye bolt.
 

I have another question. It appears the wall thickness of those struts is the same around their entire circumference. Has anyone done a calculation as to the bearing load carrying capability of the bolts in the strut wall?

Why do I ask? Long ago a friend bought a J-3. The lower end of the wing struts had been cut off with an alternate fitting bolted in as shown in your pictures. One day Mr. FAA came by, spotted it and placed a red tag on the Cub. Fortunately I had a friend who was a DAR stress analysis specialist. He looked at it and agreed with Mr. FAA. The fix was to weld on two steel straps (both sides) which doubled the wall thickness of the strut where the bolts went through.

Your struts are aluminum, the J-3 struts were steel. The bearing strength of aluminum is lower than steel.
 
The profile cannot be seen well in the picture...the inner view shows thicker “flats” in the center area and the extrusions themselves are substantial. I believe the tensile strength of these extrusions exceeds that of a steel strut...the steel struts are substantially thinner wall thickness. I don’t have the numbers at the top of my head... but I sure do appreciate feedback on this. I also am going to take your comments on the jury mounting to heart and do some research before I drill the hole. Jay is doing this on his Aluminum struts...are Javron jury upper mounts the same as Pipers? Does the clamp method introduce flexibility by spreading the load along the clamp? Or doe the clamp flex enough to add this flex into the system? Is it the single point that adds stiffness causing the issue you describe? This is interesting. Thank You Pete. I always pay attention when you respond.
 
This pic is grainy, but you can see how I mounted my jury strut tab to the spar
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