J-4a Info and Brake pedal 337

[Staggerwingse17b]

Hi All,

How come I can't find out much about the J-4a cub coupe on the internet.
Anyone have any ideas? I would like to find out more about its history, specs and its current market value. I may be purchasing one and would like to find out more than what is on the Type Certificate Data sheet.

Also, does anyone know if there is a 337 or STC that I can use for installing brake pedals on the rt side.

Thx
John

 

[d.grimm]

J-4

Have instructed in a J-4 with a A-75. A lot heavier than a J-3 and depending on the year not much interchangeable with a J-3. Real docile on the ground. I remember Clyde Smith saying not to put Cleveland wheels and brakes on because the mounting of the gear won't stand up to heavy braking. This airplane sold for about 2/3 the price of a J-3.

 

[Steve Pierce]

Jim Dyer at Univair is rebuilding a J4. I got to see it recently. It was assembled, almost ready for cover after all the boot cowl and sheet metal are fit. It is a much more complicated airplane to rebuild than the J3. Lots of compound curves, it has 10 stringers, different trim and hardly any parts or STCs available.

 

[Dan2+2]

Well they only made 1250 or so of them and from what I gather less than 100 are flying now. At oshkosh 2 years ago not a single one showed up. Some smart%&# said they were so slow they dont get here till its over. Mine cruises at 80ish. So not as much info. Prices are going up due to sport pilot but always 20% less than a J3. Cub club has some stc,s for bigger engines, and several drawings. Mine was a devil on the concrete, landing good on grass. the rt landing gear had been pranged in a ground loop in the 60,s. the repair was good except it was toed out a little which we didn't notice until the tire wore uneven. After straightening the gear leg it lands and taxis much better. Sighting down the centerline of the tire should point to the tailwire bolt on the hor. stab. Most of the trim pieces are not available. I flew yesterday and still love my J4.

 

[Longwinglover]

John,

It's all a matter of numbers.

Piper built a total of ~1258 J4's of all makes. The FAA lists ~371 still registered. ALL were built before WWII.

Piper built a total of ~20,000 J3's of all makes. The FAA lists ~5500 still registered. Piper built ~6600 before WWII.

The more obscure the subject, the more difficult to find information. There are several books published about Piper history/airplanes One of the most thorough is Piper Aircraft The development and history of Piper designs by Roger Peperell ISBN 0 85130 253 X (where I got the above information).

Piper Cubs by Peter Bowers ISBN 0 8306 2170 9 has information about the J4.

Current market value is probably what you are willing to pay for it. I don't think there is much demand for the J4. As a result of all this, parts are not as readily available for the J4 making maintaining one problematic.

STC's available for the J4 can be found here:
http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/MainFrame?OpenFrameSet

Click on "By Make" then click on "P" then Piper Aircraft then J4.

A quick review of Univair's online catalog http://univairparts.com/pdfs/piper_j4_pa_17.pdf shows available PMA'd parts limited to wing struts, strut forks and windshields.

John Scott[/url]

 

[Steve Pierce]

The other difference to consider is the comonality of parts. Piper only built 726 Clippers but a lot of the parts are comon between J3s to Tri-Pacers. Looks like a very challenging airplane to rebuild.

 

[cubunltd]

We have a J4A here and it's fun to fly. Nice and docile. reminds me of driving a '49 Merc with my arm out the window. trim didn't work and as someone said, trim pieces are non existent. We installed an Aeronca Champ trim system on it with a field approval. Works great and not a difficult conversion.

John

 

[Josh]

Just purchased a 1941 J4E what a really neat flying plane! I know...... its the bastard child but its still a cub right?.... Ferry flight permitted from Wisconsin to Florida, brakes didnt work till I got it here just pumped fluid from the bottom up and presto BRAKES!!!! Did I tell you it dont need brakes except for run up? .......with the help of this site thanks guys! Theres no mixture knob gotta turn the engine off by the mags normal??? Any guys here with a J4 that I can ask novice questions to? I have 30 year cotton thats going to be stripped soon but can you figure the only damage is where some !@!@ took a knife to the top of the fueselage about a few inches .......ohh wait is that where they did the fabric check? dunno its coming off anyways. and 2 ring worms on the gear leg thats it!!! So if you got a J4 or know much about them let me know I may need parts when the COUPE gets COVERED...... JOSH

 

[Dan2+2]

Josh, congratulations on the J4. I have a 40 J4 that I rebuilt with my dad. I love flying it. Parts are harder to come by for sure. Hopefully it sounds like you have all the parts though since you flew it home. Feel free to ask here or pm me. The continentals shut down with the mags. Most do not have a mixture control or it is wired shut at the carb.

 

[behindpropellers]

Josh-

Let me know if you need help with the wings, they are essentially the same as a J-5. Sounds like a great project, wish I had bought one to fly home!

Tim

 

[rrb]

John and/or Josh,

Send me a pm. If I recall correctly, the guy who did the prebuy for me on my J-5A had rebuilt or owned a J-4 for a while. Send a message and I'll see if I can find his contact information.

 

[d.grimm]

J-4

The J-4 is right next to the J-3 I fly If you have any questions. I annualed this plane a couple times and remember fighting with the trim and the tailwheel bungee. I think on a rebuild I would install a J-3 type tailspring and tailwheel. This one had Champ gear installed by 337 from John Hatz
of Hatz bi-plane fame. Also Porterfield exhaust system that was pretty nice. Nice flying airplane, have fun.

 

[Ruidoso Ron]

I have 30 year cotton thats going to be stripped soon but can you figure the only damage is where some !@!@ took a knife to the top of the fueselage about a few inches .......ohh wait is that where they did the fabric check?

About 40 years ago, my brother and I listed our T-Craft L-2 for sale in the Dallas newspaper with the remark......."needs recover". We might as well have said "come tear up what's left of this airplane!" Every jerk that came to see it poked a big hole through the fabric to see if we might have been lying about it. Took two rolls of hundred mile an hour tape to get it ready to ferry to Denton.