Lift Strut Data

[kmisegades]

I am searching for the coordinates of the profile used for the wing lift struts for C-170s. Noone seems to have this, not even Cessna. I can measure the coordinates from the strut on my plane, however this is not as accurate as I would like. My searches of online airfoil lists have also yielded nothing. I'm simple looking for 20 points or so from the leading to the trailing edges in standard percentage of chord values. Can anyone help me? Kent

[GAHorn]

WD Thompson wrote that the struts were not "streamlined" (probably an economy measure) and that is evidenced by the water droplets which build up and hang around aft of the mid-chord when flying in rain. It is probably symetrical however.

[cessna170bdriver]

WD Thompson wrote that the struts were not "streamlined" (probably an economy measure) and that is evidenced by the water droplets which build up and hang around aft of the mid-chord when flying in rain. It is probably symetrical however.

George isn't your airplane fast enough to blow the water off the struts?


Kent,

I'm assuming that you are talking about 170A and B lift struts? I've always assumed they used standard streamline tubing stock. That would seem to have been more economical that designing and manufacturing something special. Maybe someone has an unairworthy strut laying around that can be sectioned and compared to a standard cross section. The standard streamline dimensions should be avialable from a tubing supplier.

Miles

[kmisegades]

Miles, I contacted Cessna on this, but they wouldn't give me the coordinates and in the end claimed they didn't know them either. I guess they don't make much use of CAD yet at Cessna.... They would also not reveal the name of their tubing supplier, which indicates to me that Cessna is run by lawyers now. (Well, duh, this makes sense as Russ Meyer, Cessna's long-time former president, was originally Arnold Palmer's attorney from PA, according to the book "The Legend of Cessna") As far as I can tell, the same strut tube stock has been used on every single-strutted Cessna since the early 1950s, from the 150 to the 210. Any idea who supplies this stuff? I want to try my hand at making some improvements on streamlined fairings where the strut mates with the wing and fuselage. I know that others offer these already and I'll need FAA approval. I used to do this kinda stuff for a living, and simply want to see if I can apply my old knowledge to my C-170. Kent

[GAHorn]

I have two used struts in my hangar which belong to TIC170A. Feel free to make an offer.

[Bruce Fenstermacher]

George I'm curious. Are they A or B model struts?

[cessna170bdriver]

Kim,

For your purposes, a cheaper way than buying struts might be to use a contour gauge on your own airplane. You should be able to find a 6-inch one for less than 10 bucks.

If you are looking for coordinates for computer entry, take the top and bottom contours of the strut using the gauge and scribe them on metal on either side of a centerline, then take measurements. If you want an algebraic formula to generate the curve, send me the coodinates and I'll help you out.

Keep us posted on what you come up with.

Miles

[GAHorn]

George I'm curious. Are they A or B model struts?

Believed to be B-model struts. (Simple tape measure shows them to be the same length as my B-model.)

[kmisegades]

Miles, I have used a profile gauge and taken measurements from these with an accurate caliper. However this is not sufficient, even using some fancy spline fitting I still get undesirable waviness that is simply not there in the actual extruded profile. A laser scanner would do the trick, and I know where I can get some scrap struts. However, surely someone must have these darned coordinates. Dave Lednicer of AMI has the world's longest list of airfoils but alas not the simple and ubiquitous Cessna lift strut. Kent

[cessna170bdriver]

Kent,

If you don't mind, send me the coordinates you have and let me play with them a bit.

Miles

[N170BP]

Miles, I contacted Cessna on this, but they wouldn't give me the coordinates and in the end claimed they didn't know them either. I guess they don't make much use of CAD yet at Cessna.... They would also not reveal the name of their tubing supplier, which indicates to me that Cessna is run by lawyers now. (Well, duh, this makes sense as Russ Meyer, Cessna's long-time former president, was originally Arnold Palmer's attorney from PA, according to the book "The Legend of Cessna") As far as I can tell, the same strut tube stock has been used on every single-strutted Cessna since the early 1950s, from the 150 to the 210. Any idea who supplies this stuff? I want to try my hand at making some improvements on streamlined fairings where the strut mates with the wing and fuselage. I know that others offer these already and I'll need FAA approval. I used to do this kinda stuff for a living, and simply want to see if I can apply my old knowledge to my C-170. Kent

While I empathize (and agree) with your sentiments, not all lift struts
were the same up through the 210. The 185 and 206 (probably others,
205?) had bigger / fatter struts (same length, maybe, but the overall
profile was larger / thicker plus the wall thickness was likely thicker).

[kmisegades]

Bela, You are surely correct on this as my observations have only been that and we don't see too many of these A/C in our parts. How do you know this about the struts of larger Cessnas? Do you perhaps know who makes these for Cessna, something Cessna won't tell me. Kent

[N170BP]

Bela, You are surely correct on this as my observations have only been that and we don't see too many of these A/C in our parts. How do you know this about the struts of larger Cessnas? Do you perhaps know who makes these for Cessna, something Cessna won't tell me. Kent

A buddy of mine owns a company that recovers crashed/wrecked
aircraft, and I've taken more of them apart than I'd care to remember!
Sorry, don't know what Cessna's source was for the extrusion...

That being said... Tierney Metals in Southern California is the "Walmart" of
extrusion houses. If I was an "investigator" and had absolutely
no leads, I'd start there.

[N4005V]

The 210 does not have struts. The 170B strut is the same as the 172. It is .083X3.5 Basic round tube streamline formed on a die at Cessna.
Cord Thickness
.255 .955
.825 1.565
3.040 1.470
3.755 1.070

[N170BP]

The 210 does not have struts. The 170B strut is the same as the 172. It is .083X3.5 Basic round tube streamline formed on a die at Cessna.
Cord Thickness
.255 .955
.825 1.565
3.040 1.470
3.755 1.070

The 1960 - 1966 Cessna 210 in fact did have wing struts.

In 1967 (G model and later), the 210 went to a cantiliever wing
design.