• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

Bungees too tight

Things are slow. Even if you leave the leather bumper out and miss the slider with your bolt, it wouldn’t bring the gear in that far. I took a shortie apart this afternoon, and it wouldn’t collapse much further, because the ears hit.

The difference between the shorties and the good struts is a full inch!

We had a Cub come to town with struts that looked like the OPs. A new set was an inexpensive cure.
 
I don't remember seeing any leather bumpers so I suspect they are gone. Here are some photos with the boots removed.



IMG_6811.jpg
IMG_6812.jpg

And here is is with the old shock cords, 8.00 tires, and all the same strut pieces and the tires are straight up and down, not canted in at the bottom.

IMG_6800.jpg
 

Attachments

  • IMG_6811.jpg
    IMG_6811.jpg
    47.1 KB · Views: 188
  • IMG_6812.jpg
    IMG_6812.jpg
    70.4 KB · Views: 180
  • IMG_6800.jpg
    IMG_6800.jpg
    90.1 KB · Views: 185
Last edited:
Looks like your shock struts have been repaired/modified. Maybe your old shock cords were sagging and allowed the wheels to be perpendicular to the ground?
 
Slow here, too. I was trying to look closely at the before and after photos. It almost looks like a sleeve was put over the original lower shock strut. It's hard to tell, but the original strut looks narrower than the current one.

Did someone splice a sleeve on it and maybe shortened it a little?
 
No metal work has been done on the struts in over 30 years so no. I only stripped them, epoxy primed and repainted when I installed the bungees last year. That welding work was done before I bought it 30+ years ago. It is possible the old cords were stretched enough to make everything fit correctly over time. Not sure what to do at this point other then take measurements and try and compare to another similar year Cub.

Question: When sitting on the ground, unloaded, are the struts and cords typically fully compressed? If so, then clearly mine are wrong.
 
Question: When sitting on the ground, unloaded, are the struts and cords typically fully compressed? If so, then clearly mine are wrong.

Looking at online images of them in flight, and thus fully compressed, most look of them look like the wheels are close to vertical. I don't know enough about J-3s, but my project, a Wag 2+2, uses the same design. Fully compressed the wheels are close to vertical, just slightly canted.
 
My former PA-11 never extended the similar struts unless moving over uneven terrain. The wheels were close to vertical.

Gary
 
You cannot use these on a certificated aircraft, but they are so inexpensive that you could buy one just to look at it and compare. I highly recommend that experiment. Costs about what a good dinner for two with wine costs.

https://expparts.com/products/piper-j-3-style-shock-strut-assy

Even when mine get so old that one of them “necks” they are still potent enough to keep the shock struts fully closed when sitting empty.
 
You cannot use these on a certificated aircraft, but they are so inexpensive that you could buy one just to look at it and compare. I highly recommend that experiment. Costs about what a good dinner for two with wine costs.

https://expparts.com/products/piper-j-3-style-shock-strut-assy

Even when mine get so old that one of them “necks” they are still potent enough to keep the shock struts fully closed when sitting empty.
I wouldn't recomend EXPParts for a static display. for reason stated in the link in my previous post. When I called the owner aout alignment issues his responce was they were experimental like that was an excuse for misaligned parts.
 
I wouldn't recomend EXPParts for a static display. for reason stated in the link in my previous post. When I called the owner aout alignment issues his responce was they were experimental like that was an excuse for misaligned parts.

That subject of 'but it's experimental', alone, would make a great thread, but it might get me in trouble.

Web
 
That subject of 'but it's experimental', alone, would make a great thread, but it might get me in trouble.

Web

Ha, I could tell you a pretty long drawn out story about the return of parts and him not crediting my customer etc. He didn't realize I took a picture of the open box on the scales when he tried to say I didn't return everything. Needless to say I think he is a POS.
 
I have a strut for the early and the later J3, both 28 1/4" center to center on the bolt holes. The early one is considerably lighter. One pictured came of my wall of shame and has a bend to it that was straightened to get another Cub off the runway.
IMG_20200824_072508.jpg
View attachment 50777
 

Attachments

  • IMG_20200824_072508.jpg
    IMG_20200824_072508.jpg
    75.1 KB · Views: 138
Last edited:
Thanks for the measurement, I will grab a tape tomorrow and measure mine.
 
Went to the airport, took these shots, did four landings, came home. As soon as my stomach recovers, I am going back for six slow rolls.

Anyway, look for two different strut lengths, two different bungee lengths, and understand - I just became aware of all this in the last six months, when a bunch of spares arrived and two buddies noticed a problem on their J3s

I took some actual measurements of my strut length versus what they should be to get the tires plumb up and down. I believe my struts are 1 5/8 inches too short. Based on the struts you have there is that the approximate difference in length between short and long struts about 1 5/8? Is the length difference all in the lower piece or will I have to replace all four parts of the struts?
 
One inch difference. Not a precision measurement. Replace everything - I re-use new bungees, but getting them off safely requires a special tool and great care. Not counting bolts and leather bumpers, two parts per side.
 
One inch difference. Not a precision measurement. Replace everything - I re-use new bungees, but getting them off safely requires a special tool and great care. Not counting bolts and leather bumpers, two parts per side.

does anyone know if the serial numbers prior to 7xxx had the long struts or the short struts?
 
To change the subject slightly Steve, when you inspect the shock cords what do you see that might cause you to change them? Ours are 5 years/900 hours old but still look like new. The wheels sit vertical on the ground.

cheers Bill
 
Swelled up knots in the outside fabric cords. The individual bungee strands break and knot up. Met a Husky guy at the gas pump recently who's mechanic want to change his bungees because the cotton covering had some tears. I told him that his bungees looked plenty tight and that cotton covering gets torn when installing.
 
Swelled up knots in the outside fabric cords. The individual bungee strands break and knot up. Met a Husky guy at the gas pump recently who's mechanic want to change his bungees because the cotton covering had some tears. I told him that his bungees looked plenty tight and that cotton covering gets torn when installing.


Thanks very much Steve, I’ll leave them and monitor.
I have new ones on hand but my friend who owns the tool I use is not that keen to do it more than we need to 😀

cheers Bill
 
When one "necks down" I change them all. Happens about once every 15 years, with 75 tach hours per year/pavement.

I cannot answer for operating in rough stuff - I operate 99%+ on paved surfaces. I did break all four on a memorable takeoff in the Arizona desert half a lifetime ago - did not realize it until I touched doown at Cochise, and felt a lot lower than usual on taxi-in. The cure was some clothesline from the local market.

Those big safety cables are for when you break something made of steel. The shock struts will save you if you are careful.
 
Back
Top