radiator hose on front struts of Cherokee?

Aaron H

Aaron H

Pre-takeoff checklist
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Aaron
I've read about some people putting a radiator hose on the front struts of there Cherokee if they fly grass strips to stop the strut from fully collapsing.

Anyone have a pic or can explain this further?

Thx
Aaron
 
It is a pretty common mod in Alaska on 182s and 206s as well. It prevents or at least reduces the bottoming out of the nose strut. The FAA has been trying to stop the practice for a while now but it does actually work, so there you go.

You can see it installed on this 182.
182nose strut.jpg
 
Thx Stickman,

Couple more questions if you don't mind.

Do u measure the diameter of the strut and match that with the inter diameter of the hose or do u want some extra room?

Hose clamps on top and bottom?

How tall is the hose?

Do you take the wheel off to install it or cut a slice in it?

Why does faa want to stop it if it works?

Thanks
 
The hose should have the same inside diameter as the struts outside diameter. The planes I've seen up close the hose was split and trimmed to fit. The hose in the picture is actually taller than most, I picked it because it was the easiest to see detail.

The FAA is concerned with the hose clamps shifting and causing damage the the strut seals is what I was told. I think that fewer pilots are using this method than a number of years ago. These days it seems like most just over inflate the struts.
 
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I added about 2” of radiator hose to the strut of my old Hawk XP about 20 years ago to maintain flat strut prop clearance minimums. I did it as part of a field approval to install an 80” seaplane prop when on tires. My strut was disassembled and the hose put on. No worm clamps. The inside of the hose got a coating of grease to reduce corrosion. The FAA didn’t take any exception to doing it then, and in fact a friend with a similar plane did the same thing on a different plane.
 
Thx Stewart,

That was going to be the next question, how big of a piece.
I like the idea of removing the tire instead of sitting it and using hose clamps
 
Stewartb said:
I added about 2” of radiator hose to the strut of my old Hawk XP about 20 years ago to maintain flat strut prop clearance minimums. I did it as part of a field approval to install an 80” seaplane prop when on tires. My strut was disassembled and the hose put on. No worm clamps. The inside of the hose got a coating of grease to reduce corrosion. The FAA didn’t take any exception to doing it then, and in fact a friend with a similar plane did the same thing on a different plane.
Click to expand...
That’s a good point, it’s not the rubber hose the FAA objects to but the clamps.
 
Sounds like a good cheap way to increase the odds of not having a prop strike on a hard landing.
 
One of the drawbacks of using that hose is the shortening of the overall stroke. That can place extra forces on the nosegear attach points when the hose bottoms out on a hard landing. Some airplanes, notably the 172, sure don't need any more stresses on that flimsy attachment.

Anybody that gets a prop strike on a hard landing in a trike needs to learn to fly all over again. Airplanes are designed to have some prop clearance with the strut fully collapsed and the tire completely flat.
 
Good point dan, wonder why it is such a common practice in certain areas, like Alaska?
 
Long props. Limiting a collapsed strut is necessary to
maintain clearance.
 
Aaron H said:
Thx Stewart,

That was going to be the next question, how big of a piece.
I like the idea of removing the tire instead of sitting it and using hose clamps
Click to expand...

Removing the tire wouldn't do it, you'd have to take the strut apart. Even then I don't know how one would fill the strut with hydraulic fluid without fully compressing the strut.
 
Dan Thomas said:
One of the drawbacks of using that hose is the shortening of the overall stroke. That can place extra forces on the nosegear attach points when the hose bottoms out on a hard landing. Some airplanes, notably the 172, sure don't need any more stresses on that flimsy attachment.

Anybody that gets a prop strike on a hard landing in a trike needs to learn to fly all over again. Airplanes are designed to have some prop clearance with the strut fully collapsed and the tire completely flat.
Click to expand...

I'm not sure the "extra forces" theory stands up to critical thinking, Dan.

I gotta think that the hose is going to give...substantially...and cushion the "smack. If you land hard enough to over stress the assembly by smacking on the hose, then I gotta think that you would have also completely bottomed out the strut had the hose not been there...and in that case there is no give, it's solid...and overstress is just as likely?
 
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The hose doesn't provide much give. In my case I had 26" mains and an 800x6 nose tire. The point of the big tires was to make off airport ops better, and I never had a problem. The 80" CS prop was approved on floats only so factory XP seaplanes were delivered with ferry permits. I didn't want to buy or use a 76" prop so getting the 80" prop approved was important. I'd be surprised if there aren't 182s running around on tires with 88" seaplane props. They likely have the same issue.
 
One can achieve the same thing as the hose by filling the strut with fluid while it's extended a couple of inches. That keeps it from bottoming out, and the gas, as it compresses, limits any shock loading on a hard landing.

But with a long prop, any loss of fluid means a loss of prop clearance.
 
I like the practice, all the 206s I’ve seen on wheels had them.

I’d put one on too (no clamps), but I have never owned a trike ;)
 
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