Thorp Air Command - T18.net

That may be harder than you think - they've banned those big round bails in many states. The politicians were afraid the cows wouldn't get a square meal!

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John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE

"Let them eat cake !"


RB

Cubes, do you carry Heim F-31-14 rod end bearings as shown on the left end of sheet 501 (Aileron actuator tube)? Mine needs replaced and Aircraft Spruce doesn't seem to have it in their catalog.

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John Twigg N12055 SN.79 Pittsburgh, PA (KFWQ)

Actually, no. I've been looking for those for quite some time. If someone has a source, I sure would appreciate some insight.
Cubes

Even Van's has had to substitute.

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Bob Highley
N711SH
SN 835
KLAL

What are they using?
Cubes

Funny...can't find a listing for the Heim F31-14 bearing , but I did find what I think is a cross reference for the little bugger ! I came up with MS21152 , but you will have to sell your blood to pay for it !

RB

It is a non-aviation commercial rod end. It has a brass looking bearing with no balls or rollers. Don't recall if it has a witness hole or not. Needs to be lubed often.

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Bob Highley
N711SH
SN 835
KLAL

That rod end looks like the same rod end Cessna uses (S1581-4) but the shank on the Cessna is only 3/8 diameter so it isn't of any use in this application. The last Cessna rod end I bought came from Aurora (replaced the Heim several years ago as the supplier) with the part number MW-4M-5 ink stamped on the end. Thinking it might be a good starting point, I tried to look it up in the Aurora catalog but I didn't find that part number let alone a part number for the correct size. Maybe someone else will have better luck.

I wouldn't want to use a hollow shank rod end like the MS21152. The shank should be solid with no threads in an application like this. Seems to be very hard to find. Would it be acceptable to replace the aluminum tube with some smaller 4130 to fit the Cessna rod end?

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

Wow - that MS21152 rod end is expensive... My existing rod end is very hard to rotate/spin. The other end is perfect. No rust or anything - just stiff. I put WD-40 and regular machine oil in it which helped a little. Maybe I need to grease it better... I once was browsing and came across a rod end "regreaser" that somehow pushed out the old grease while pushing in new. Have you guys ever heard of or used those?

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John Twigg N12055 SN.79 Pittsburgh, PA (KFWQ)

The rod end in question is not adjustable per the drawing. The F-31-14 rod end is riveted in. If yours is threaded, it was likely done that way because the rod end desired could not be located. Not many applications use an adjustable rod end on both ends because it could conceivably come undone. The only push rods adjustable on both ends I have seen in aviation were safety wired using special keyed washers with safety wire holes to secure the jam nut to.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

Jeff J - sorry, bad grammar on my part. My actuator tube and the rod ends are built correctly. It's the bearing inside the non-adjustable rod end (left side of sheet 501) that is not as free to move as it should be. I'm hoping to force new grease into it to make it move more freely.

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John Twigg N12055 SN.79 Pittsburgh, PA (KFWQ)

You can buy rod end greasers from most AV parts houses . Spruce has them for about $15 if I remember right . I have one , but have not tried it yet .

RB

John, Not bad grammar. My mind was stuck on the MS21152 rod end when I read your post. I don't consider WD-40 a good choice. I know a lot of people use it for a lube but it wasn't designed as such and I have seen it gum things up. For what it is worth, I prefer Aerokroil or PB Blaster for working things loose. I use LPS 2 or Rem Oil for a light weight oil.

I sent Aurora Bearing Company an email last night asking them if they build a rod end for this application. I will post the results when/if they respond. I expect if they make one it will have to be ordered from an aircraft manufacturer (Cessna, Piper, Mooney...).

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

The MS21150 is close. http://www.aircraftspruce.com/catalog/a ... kkey=45921 May not have to ream the tube to make it fit since the shank is only .430. It would be pretty loose for anyone just replacing an end if the tube was previously reamed to .437-.438.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson