Forum: F-16 Design & Construction

According the manual, the F-16 tire dimensions are the following:

Main Gear
Tire size 27.75 x 8.75 - 14.5 24 Ply
Stroke 10.5 in
Static Rolling Radius 11.9 in

Nose Gear
Tire size 18 x 5.7 – 8 18 Ply
Stroke 10 in
Static Rolling Radius 7.5 in

Can somebody explain to me how these dimension figures can be explained? For example lets examine the main gear tire sizes. Can somebody refer the "27.75 x 8.75 - 14.5 24 Ply" to each letter appeared into the following sketch?

Thanks in advance for any possible help

F-16.net Sponsor

I learned that in Tech-school, but damed if i know now

BTW there are two different tire sizes

Shortcut wrote:

I learned that in Tech-school, but damed if i know now. BTW there are two different tire sizes

These dimensions are for the "CJ" Block 50 version. What I really need to know, are the external diameter (measure A into sketch) and tire width (measure C into sketch) dimensions. Any other data is always welcome...

Static Rolling Radius is the distance from the middle of the wheel to the surface when the aircraft is still. (not on your chart)

Tire Stroke is how much the tire can "deflect" or bend under load from what I understand.

According to Michelin the Block40/50 MLG tire is 27.75x8.75R14.5 and the NLG tire is 18x5.7-8/18

So the MLG has a 27.75" Outside Diameter (A), with an 8.75" Side Wall height (D), on a 14.5" rim (F).

The NLG is an 18.5" Outside Diameter, with a 5.7" Side Wall height, on an 8" rim.

At least that's my stab at the question... Shrug

(As an Engine Guy it's not truly my thing)

Ref: http://www.airmichelin.com/pdfs/MIL_F16X.pdf

Keep 'em flyin' Thumb

TEG

"27.75 x 8.75 - 14.5 24 Ply"

(A) 27.75''
(C) 8.75''
(F) 14.5''
24 is bias tire ply-rating

'Static Rolling Radius' is as TEG said.
'Stroke' I don't know.

There is no such thing as "tire stroke", as stroke refers to the extension and retraction of the shock strut. Look at the stated main gear stroke of 10.5 inches. No way the tire could compress or deflect that much.

That_Engine_Guy wrote:

So the MLG has a 27.75" Outside Diameter (A), with an 8.75" Side Wall height (D), on a 14.5" rim (F).
The NLG is an 18.5" Outside Diameter, with a 5.7" Side Wall height, on an 8" rim.

Thank you all for quick answer! Regards Very Happy

johnwill wrote:

There is no such thing as "tire stroke", as stroke refers to the extension and retraction of the shock strut. Look at the stated main gear stroke of 10.5 inches. No way the tire could compress or deflect that much.

I agree that the "tire stroke" of the MLG on the Viper can't be 10.5" as the sidewall is only 8.75" But there IS a term called "tire stroke" and it does refer to the "deflection" of a tire. I never said the Viper had a "Tire Stroke" of 10.5", simply defined "tire stroke" as he was talking about the tires...
Guess I wasn't thinking about the MLG as a whole? Shrug

The diagram didn't show the gear.
(Next time I'll have one less beer and go into further detail... Rolling Eyes

)

I also agree that "Wheel Stroke" or "Gear Stroke" would be the distance the "Wheel Assembly" can move in a vertical motion. This may or may not be the stroke of the strut. (IE, the strut may compress 4" but travel of the wheel may be 6" due to the mechanical leverage of the gear as a whole)

The strut on the Viper may have a 10.5" stroke, but doesn't the MLG have a lot more vertical travel when the leverage of the entire suspension is considered? (At least it looks like more than a foot when they're landing...)

Keep 'em flyin' Thumb

TEG

In the engineering community, tire deflection is never called "tire stroke", but in your world, evidently it is. I didn't intend to say you said tire stroke was 10.5 in. I was referring to "Stroke 10.5 in." in the first post, then you defining "Tire stroke is how much the tire can "deflect" or bend under load.."

You are right that the F-16 main gear geometry results in the wheel displacement being greater than the shock strut "stroke", but it's not much different. I don't have the equations, but would guess it is maybe 15% greater. The nose gear wheel stroke is also close to the shock strut stroke.

If 8.75'' is the sidewall of the MLG (''D'' in the fig.) then ''A'' must be equal to ''F + 2 x D''. It does not add.

I think 8.75'' is ''C''.

If you refer to the PDF file referenced above, 8.75" is clearly the "Sidewall" height, not the tread width.

After doing some "Googling" I did manage to find a reference to "tire stroke": PG 104 in the following document?
http://books.google.com/books?id=XMpdOe ... ear+design

(Though I may be reading it wrong?) Shrug

Keep 'em flyin' Thumb

TEG

There is indeed a reference to "tire stroke" on p104. However, the ref is "tire stroke (deflection)" and the meaning is the contribution of "tire deflection" to total gear stroke. On pages 80, 81, 83, and 128, the same quantity is called "tire deflection".

Sure, we're both nit picking, but that's part of the fun of this conversation.

Respects,

That_Engine_Guy wrote:

If you refer to the PDF file referenced above, 8.75" is clearly the "Sidewall" height, not the tread width.
........

Is the 'SW' stand for Side-Wall or Section Width?

I think it is Section Width.

For example from the link:
http://www.goodyearaviation.com/resourc ... itions.pdf

In the table it is said that the second number is for ''Nominal Section Width''.

r2d2 wrote:

That_Engine_Guy wrote:

If you refer to the PDF file referenced above, 8.75" is clearly the "Sidewall" height, not the tread width.
........

Is the 'SW' stand for Side-Wall or Section Width?

I think it is Section Width.

For example from the link:
http://www.goodyearaviation.com/resourc ... itions.pdf

In the table it is said that the second number is for ''Nominal Section Width''.

Good point, I think you're correct! Cheers

Guess that's why I don't change tires? Shrug

TEG

Forum: F-16 Design & Construction

F-16 tire sizes