Plan to build a bungee installation tool ?

Thanks guys for your answers.
Now I have a very stupid question... I know that is stupid but as I am still stuck I will be brave and ask my dummy question.

If you extend the shock strut, but the triangular legs of the pipercub remain the same, then it should just spread the wheels on both sides, and extend the distance between them, but the airplane would not be "higher".
Some dummy like me could even conclude that it would rather reduce the clearance between the prop and the ground than increase it.

So I know this is not the case, but I do not understand why.
Do you also modify the cabane vee when you install extended struts?

Alexandra

Larry G said:

With the 3" extended gear you would need longer bungee system you could order them with the bungee cords on already.

Click to expand...

Not true.

The stance and prop clearance both increase. Not a lot though. I like the wider wheel base. The cabane is unchanged. You simply bolt on the new gear. You reuse the old hydrasorb/bungee units after installing the longer struts.

Your questions are not "dumb."

Naaalex said:

Thanks guys for your answers.
Now I have a very stupid question... I know that is stupid but as I am still stuck I will be brave and ask my dummy question.

If you extend the shock strut, but the triangular legs of the pipercub remain the same, then it should just spread the wheels on both sides, and extend the distance between them, but the airplane would not be "higher".
Some dummy like me could even conclude that it would rather reduce the clearance between the prop and the ground than increase it.

So I know this is not the case, but I do not understand why.
Do you also modify the cabane vee when you install extended struts?

Alexandra

Click to expand...

Thanks Eddie.
Fairly simple... now let's check on the Univair website to answer the bad question... "how much?"

Check with airframes also they ship a lot overseas and should have a good ideal on how long it will take and the price.
DENNY

Planning to add bigger tires? My friend has 3" extended gear and 8:50 tires, I have flown his airplane a few hours. A real bugger to climb into because the tire is so much further from the fuselage. My experience only, Jim

Check your fittings over too

Waouuuwww ! Not nice...

Alexandra:
Just a few thoughts / comments on your project.

1st thought is.... You are not "dumb". You appear to be very intelligent with a lot more experience and skill than you let on, and not afraid of new challenges. I know lots of guys that would not tackle what you are trying to get done. So Atta Girl!

2nd is I would agree that you may have corrosion in the lower tubes. But inspect them before throwing them out. But having said that, new ones could be good insurance and add "peace of mind".
If you can't see clearly get a borescope, as they are cheap nowadays.

3rd: The idea of extended heavy duty gear is a very popular idea for those that are seriously working the airplane hard. It is also popular for many that will never leave the traffic pattern but they like knowing that they could if the notion hits them. Your airplane is a very light weight cub with maybe a 1500 lb gross weight. You are also running small tires and original gear so I can't imagine you getting to far into the rough stuff on purpose.

To convert to the heavy gear vees is one thing but to extend 3 inches it may be an expensive proposition in that it may require hydrasorb gear. I have not heard of an "extended sleeve type strut" as you have. (someone else may have better knowledge on this.)

To go to all of the heavy gear stuff you would also want to check the cabane vee as I think your airplane uses smaller 1/4 inch bolts. The higher gross weight cubs will have 5/16 bolts. Not sure if the fittings are thinner on yours as well. And of course big tires are always wanted....

All of this cool stuff will require a big pile of money and if I am reading between the lines correctly that may not be an option.

4th: Installing the cords.... The Stewart system tool is a good one but it appears to be only for loading hydrasorbs. which will not work for you. I tried to find more info on this but their web site is down.

The option of using the hoist that you have is your best approach as you have said you are not very strong and may want to avoid the "flip over technique. Can't blame you as I also avoid that one as well.

I used the hoist method today to load a set of hydrasorbs with 1280hd and 1380hd cords. It was abit sporty with the heavy cords but all went well.
Your most likely using 1080HD cords and these would be a "non event". Just don't use cheap rope or straps like the guy suggests. I broke a smaller strap with a 1280 cord and it was no big deal. Nothing went flying across the shop or anything. Have some help available for this.

5th When you get the new cords on. Install the Atlee Dodge safety cables and go fly, but don't try to do any of that Bush Pilot stuff.

Take Care

Thank you Ed !
Well I do not know if I deserve so much but I must say I am flattered

Ok I will inspect the tubes with my borescope as soon as I remove the bungees. At least I will see if there is any corrosion. But as you say a 65-year metal fatigue is still a reality even with no visible corrosion. In case it looks good I may use them for some more 6 months so that I get the money to replace the whole thing. The safety cable are also something I discovered recently but I really think about it.

And you are right : I love landing in rough terrains in the middle of nowhere but I still have to remember my plane is an old 65-year lady with 65-year old bones, and I need to moderate my ambitions. Moreover, I have no flaps (old military version) and the 95-hp engine was replaced by a 100-hp continental but it remains quite a small engine.
The absence of flaps is quite a limitation for STOL operations, I really need to be careful sometimes depending on the wind.

That is why I will probably keep small wheels despite my dreams, to make sure I do not have too many temptations :roll:
I have the opportunity to fly D140 airplanes (French wood&fabric plane) on rough strips and on snow/ice in a flying club so that removes some of the frustration.

I still wonder if I could put skis on my Piper, not sure because I would need retractable skis (departing from a runway) and I am afraid that it would be quite some weight added to the plane, and also some stress on the gear. Definitely not something I should do with the old shock struts !

Well I will send you borescope pictures as soon as I have some
I wonder if the tubes really move one along the other, because I tried to move them with the bungees on and that seems to be stuck. But it is probably caused by the heavy pressure of the bungees.
When assembling the tubes back together, what kind of lubricant would you add, if any ?

BTW, I bought 1280HD shock cords (Univair ref U31322-005 ).

Happy landings,

Alexandra

1280s for a 95hp cub?

Yes.
The parts Catalog gives this reference : 31322-05
The corresponding reference on the Univair website is U31322-005.
It also corresponds to my airplane S/N.
And it seems like it also corresponds to the 1280HD reference (unless the Univair website is wrong on their description for this reference).

My airplane is a former 95hp plane modified with a O-200 engine, so 100hp (not much more).

tempdoug said:

1280s for a 95hp cub?

Click to expand...

1 1280HD and 1 1280 works great on a 850 to 900lb Cub

Glenn

I have read that on the forum recently, the idea of mixing the bungees for medium piper like mine.

I must say that when I ordered my bungees some months ago, I just went the simple way : check the reference on the parts catalog, find it on the Univair website, then grab your credit card...

So I ordered 4 rings of this :
www.univair.com/piper/piper-j-3/view-all/u31322-005-piper-shock-cord/

My aircraft S/N is 18-1429 so it corresponded to the description.
Is that wrong ?

Alexandra

By the way, a guy has a bogert bungee tool in the hangar next to mine (they never used it).
Is it okay for non-hydrasorb struts ?

It may require some muscles to operate so I am still considering the hoist

Naaalex said:

I have read that on the forum recently, the idea of mixing the bungees for medium piper like mine.

I must say that when I ordered my bungees some months ago, I just went the simple way : check the reference on the parts catalog, find it on the Univair website, then grab your credit card...

So I ordered 4 rings of this :
www.univair.com/piper/piper-j-3/view-all/u31322-005-piper-shock-cord/

My aircraft S/N is 18-1429 so it corresponded to the description.
Is that wrong ?

Alexandra

Click to expand...

you did the right thing, some of us fudge a little.http://www.sbcindustries.com/products.htm 4-HDs starts out a little stiff on a light plane.

tempdoug said:

4-HDs starts out a little stiff on a light plane.

Click to expand...

As in not ever moving for the next 5 years.

Glenn

To be fair, I am getting a little confused now about this bungee story
:roll:

So you mean the documented reference is not appropriate, as far as the community is concerned by their "hands on stick" experience ?

cubdriver2 said:

As in not ever moving for the next 5 years.

Glenn

Click to expand...

Hi Glenn

In case you put one HD and one non-HD on each strut, which one do you put first (central position) and which one in second (external position) ?

Naaalex said:

Hi Glenn

In case you put one HD and one non-HD on each strut, which one do you put first (central position) and which one in second (external position) ?

Click to expand...

As long as you don't put the same ones on the same side I don't think it matters. If I was paying attention at the time of installation I don't remember.

Glenn

In that case if I were to choose I would but the HD first
My best guess.

Hi guys,

So... I have removed my old bungees. I could have just cut them but I decided to remove them with the hoist to see if the technique works fine, as a first experience before I manipulate the new bungees

Well, it works fine ! Even for a woman alone (well, if you do not count the dog. The dog is the supervisor).
The ropes I used look thin but those are very strong little ropes used for sailing boats (competition stuff). And I used heavy chains and boat fittings.

It was important that I put a piece of wood between the ropes to spread them appart, and I gently applied some pressure with a screwdiver to help the bungee slide on the other side of the strut's ear.




So I opened my struts.
Obviously one of them was replaced at one time or another in the airplane's life, and the other one is probably 65 years old. You can see the old dark-green military color of the paint and some reinforcement welded that are probably an "improvement" from the French Army (as they have this tendency to always think that they absolutely have to improve things even when they do not need to be improved...).

The newest one could slide freely and still had some grease. I do not see evidence of a corrosion concern.

The old one... was like stuck, I had to force to separate the two parts (but I finally could do it by hand). I could see some rust even without removing the bolt. The bolt was a nightmare to remove, I needed penetrating oil, vice, tools, hammer... When I finally removed it, is was rusty, bent, damaged.



The female part of this old strut may be still ok. This is something I will make sure tomorrow after a night with penetrating oil to clean it and a borescope inspection.
But the male part is very rusty and will be discarded.

I could not even remove the stuff from inside the tube as it is so rusty !



I need help from the Supercub community for 2 things.

Inside, the leather bumpers are still there (well I will replace them of course).
There is a metal part that is sliding inside the tube, between both leather bumpers, in which there is a hole for the fastening bolt.
I want to order it as well but it does not appear on the parts catalog ?

My other problem is the bolt itself. I want to replace it on both struts but I could not find it on the parts catalog either. It looks like an AN4-something.
Does anyone knows ?

(Piper 18, year 1951, S/N 18-1429, no hydrasorb, used to be equipped with a 95hp engine)





Some would say that I am not lucky to discover this.
Well I consider myself as very lucky !
At least the disassembly was not useless, and today I may have saved myself from an off-airfield nightmare with prop strike and big damage
So that's cool 8)

Happy landings to all

Alexandra

Your doing great. I used a 1" wide strap instead of a rope on the new bungees because the strap spreads the load out and doesn't sink into the bungee as far. Nice Job

Glenn

I would be that brave if I was part of a free health care system,Glenn is from the home of the BRAVE.the FREE part we gave up. but now you see you could have and should have bought all new at once,plus 60 dollars to install ,shipped all together plane down one day.and the new bolt would have been included.This is called insurance. Those cords will be stiff. used two hds on 160hp cub land only on black top took 5 years to get them to move.

Hi !
Thanks

I was afraid that a wide strap gets stuck below the bungee, didn't you have this problem ?

Naaalex said:

Hi !
Thanks

I was afraid that a wide strap gets stuck below the bungee, didn't you have this problem ?

Click to expand...

Just make a loop and hook both ends and after you get the bungee on release one side and it will pull right out

Glenn

That metal sliding piece is not replaceable as an individual part, that is why it is not shown on the diagram. The bolt is an AN4-14, maybe a 15 if you use 2 washers as shown in the diagram.

Hi guys,

Glenn : thank you, yes that makes sense with the wider rope, I will do that to install the new bungees !

Cruiser : Yes you are right, the sliding part is trapped-welded inside the tube. This was not possible to notice on the first short strut because the end was very rusty, but I could see that on the second one. The Univair team also confirmed that they sell the whole part fully ready-to-use with sliding part + leather bumpers inside.


So I opened the second short strut.
When I started turning the wrench on the bolt I expected it to be a bit stuck, but in fact the bolt broke (inside the nut) at the first attempt with the very first light effort.




I was a bit surprised... and happy again that I decided to take care of this landing gear !
Then the bolt came off easily from the hole, with no corrosion at all.

Appart of that, this short strut looked good, no pitting, not bent, the sliding part moves freely.




(on the above picture I removed the remaining paint with MEK on the sliding area)

Nevertheless I decided to buy my peace of mind and replace both short struts by new parts.
At least they will be both new, both straight, both reinforced on the ears, and I would guess that it is always better to keep things symmetrical on an airplane.

Now I will clean, sand and inspect the long struts. I already performed a borescope inspection inside but it needed to be cleaned more thoroughly so that I can really see the condition.
I will probably remove all the paint and perform a dye penetrant inspection too (peace of mind again).

Questions from a newbie to the aces :
How would you paint the new short struts ? They come with a layer of primer already but no paint.
Of course I need to protect the sliding area inside the short strut from paint, but I noticed that most of the paint outside was gone on the part of the tube that slides inside the long strut.

And for the assembly, what grease would you use inside the short strut if any, and outside between the long strut and the short strut ?
I would have said ASG 17 or 64 maybe for the sliding property with molybdenum disulphide ?

Happy landings

Alexandra

Hi guys,

I was travelling for some weeks + got the flue, so the Cub remained half naked in the hangar
Now I'm back on this stuff !

So I finally ordered 2 new short struts from UNIVAIR and painted them.
Here they are, ready to get their new bungees, with some molybdenum grease inside :



Yesterday I tried to install the bungees with the hoist, but the fastener broke because of the tension.. Let's conclude : there is some tension in those bungees



Today I resumed the work with stronger stainless fasteners.
In fact after a short brainstorming and one or two attempts, I found the perfect configuration so that the operation becomes fairly easy...

The bottom fastener is only there for safety, once the bungee is under tension, it can be removed if needed to help pushing gently the strut towards the bungee to put it in place.

The only annoying thing is that the new bungee is preshaped with the sewed area located exactly in the middle, so it requires some efforts to position it so that it does not end where the bungee will be folded (not recommended).



Above pictures : Bungee number one... apply tension, push gently... it's on !
The hardest is to remove the ribbon trapped in the bungee
The dog supervises to make sure the human does not make anything silly...



Second bungee : same method, same result : it works !
Quickly and easily done... in fact the hardest was the brainstorming before the work

The covers are ready to be put on with grommets (in fact there was no grommets when I removed them... so the covers were moving freely and they started to damage the struts and cause some superficial corrosion + some superficial wear on the previous bungees).



Okay, now everything is ready !
I guess those legs will soon be back flying and bouncing in the mountains

Done ! Ready to fly.

I wanted to thank you all guys for your help during the brainstorming.
That was really helpful.

I must say also that the picture that Glenn posted really helped me to find the best way to play with the hoist

Happy landings to all,

Alexandra