Tire inflation pressure

Mark Hickey wrote:


Consider that a pneumatic tire supports the weight by the air pressure
that's in it - and that the contact patch of the tire is approximately
the weight on the tire in pounds divided by the pressure in psi. That
means on the hypothetical plane above (2,250 pounds, 15psi), the
contact patch (total) for the three tires would be around 150 square
inches. That's 50 square inches per tire, which on a 5.00 tire is
otherwise known as "a flat".

Mark Hickey

Agreed. More accurately, however, for this airplane there would be
about 1000 lb on each main at gross weight which, as you note, would
result in very flat 5.00-5 tires at 15 psi. The 45 psi recommendation
is correct.

- anon

"VideoFlyer" wrote in message
...
45 lbs??? 55 lbs for the nose gear??? That seems awfully high.
Those tires
will be hard as a rock. I guess I'd prefer a little softer tire to
land on. I
rarely put in more than about 15 to 20 lbs. 5 lbs will "get the
sidewall off
the ground."


It would depend on the all up weight of the aircraft, our Rallye 100
weighs in at a gross weight of 1700 lbs and the tire pressures are 21
in the nose wheel and 25 in the mains.
--

..
--
Cheers,
Jonathan Lowe
whatever at antispam dot net
No email address given because of spam.
Antispam trap in place

Ben Haas wrote:

Hey, that BOb is sooooo happy he is using my name ....I will post the
thread where BOb got honest with us about 50 years of accident free
flight.It is titled HI VIS Paint, For your reading pleasure and a good
laugh read the whole thread to see BOb unravel and back peddle. I
cannot wait to see what new heading he will use with my name in it.
G.....
B. B. wrote in message . ..

Lets see what airplanes have you have built and fly? Would love to see a picture
of them. A single engine Private Pilot. How much IFR do you fly Ben? Lets hear
some of your riveting stories...ok? You seem overly obsessed with Bob. Maybe a
little jealous or are you just infatuated with him and afraid to show how you
really feel? Maybe you have a really strong crush on him.

Jerry

Well....you're right, -anon. I obviously have no experience with 5:00-5 tires
on a 2250 lb gross weight canard aircraft or I wouldn't be "spewing" such
ignorance. But you might notice that I didn't say in my post that 15-20 lbs was
the correct, or even recommended, pressure. I am sorry to have contaminated
this group with an opinion, an observation and personal experience. Mea culpa,
mea culpa.

My experience with 5:00-5 tires is on much lighter aircraft. And while I
didn't mean to be "spewing ignorance" my experience nonetheless is that
pressures of 45-55 lbs makes the tires on my Rans pretty hard. If you would
like to tell me that my experience is not valid somehow, feel free.

To the original poster...if you want truly accurate information on this
newsgroup, "anon" is the person you want to consult. If you're looking for
feedback from other people interested in this hobby, better check with "-anon"
as well...just so you don't get splattered with more "spewed ignorance."

Flyer (foot firmly implanted in mouth)

anon wrote:

Peter Dohm wrote:

n o t n e c e s s a r i l y

Trivial in this case, as the tires were not alleged to have gone flat.
However, it is a frequently employed method to protect the wheels, and
sometimes the tires, while the parts (tubes in this case) are obtained.

IIRC, no assertion was made that this was an adiquate temporary service
for flight, or even ground operation.

Peter

My bad. I incorrectly assumed that his #1 response was his reply to
the first question about correct tire pressures and his #2 response
was his reply to the second question about flat tires. His reply
makes perfect sense now that I realize, thanks to you, that both
answers were in response to the flat tire question. Apologies to all
concerned. My pressure recommendations stand. I will now slither
back under my rock.

- anon

I really was not trying to be that much of a prick.

Especially for a canard aircraft, for which there is probably not a formal
POH, the tire manufacturer may be of some help.

My recollection, admittedly as a student-pilot twenty years ago, is that a
Cessna 150/152 with the optional 6.00x6 main tires (5.00x? was standard IIRC)
had generally better balanced handling with around 25 psi in the main tires
than with 30 psi; which I believe was recommended for the standard tires.

The problem that it corrected was not so much that the mains were "bouncy",
at the higher pressure, although they were and the lower pressure corrected
it nicely; but that the plane did not gain excessive speed on the taxiways
at just above idle. Therefore, you could reasonably warm up the engine and
taxi out at the same time without additional wear on the brakes. In other
words; it was practical to be kind to the FBO, even when renting by hobbs
time.

There was a very small increment in the take-off roll on smooth concrete,
which probably would have been an equally slight decrement on turf or very
well maintained grass, when compared to the higher pressure. And, of course
much less braking was required after landing...

Peter

(VideoFlyer) wrote:

Well....you're right, -anon. I obviously have no experience with 5:00-5 tires
on a 2250 lb gross weight canard aircraft or I wouldn't be "spewing" such
ignorance. But you might notice that I didn't say in my post that 15-20 lbs was
the correct, or even recommended, pressure. I am sorry to have contaminated
this group with an opinion, an observation and personal experience. Mea culpa,
mea culpa.

My experience with 5:00-5 tires is on much lighter aircraft. And while I
didn't mean to be "spewing ignorance" my experience nonetheless is that
pressures of 45-55 lbs makes the tires on my Rans pretty hard. If you would
like to tell me that my experience is not valid somehow, feel free.

While your experience is of course valid, in this case it wasn't
relevant to the poster's question. The poster's 5.00-5 tires must
support about 1000 # each at gross weight. That fact dictates the
minimum tire pressures. And let's not pretend to be the wounded
innocent. Your post was written in direct rebuttal to my post and
called my pressure recommendations into question. Yours wasn't the
innocent ancillary informational post that you now pretend. In
retrospect, however, I should have used more tact. For the record,
here is your post:

45 lbs??? 55 lbs for the nose gear??? That seems awfully high. Those tires
will be hard as a rock. I guess I'd prefer a little softer tire to land on. I
rarely put in more than about 15 to 20 lbs. 5 lbs will "get the sidewall off
the ground."

- anon

anon wrote:
(VideoFlyer) wrote:


Well....you're right, -anon. I obviously have no experience with 5:00-5 tires
on a 2250 lb gross weight canard aircraft or I wouldn't be "spewing" such
ignorance. But you might notice that I didn't say in my post that 15-20 lbs was
the correct, or even recommended, pressure. I am sorry to have contaminated
this group with an opinion, an observation and personal experience. Mea culpa,
mea culpa.

My experience with 5:00-5 tires is on much lighter aircraft. And while I
didn't mean to be "spewing ignorance" my experience nonetheless is that
pressures of 45-55 lbs makes the tires on my Rans pretty hard. If you would
like to tell me that my experience is not valid somehow, feel free.


While your experience is of course valid, in this case it wasn't
relevant to the poster's question. The poster's 5.00-5 tires must
support about 1000 # each at gross weight. That fact dictates the
minimum tire pressures. And let's not pretend to be the wounded
innocent. Your post was written in direct rebuttal to my post and
called my pressure recommendations into question. Yours wasn't the
innocent ancillary informational post that you now pretend. In
retrospect, however, I should have used more tact. For the record,
here is your post:


45 lbs??? 55 lbs for the nose gear??? That seems awfully high. Those tires
will be hard as a rock. I guess I'd prefer a little softer tire to land on. I
rarely put in more than about 15 to 20 lbs. 5 lbs will "get the sidewall off
the ground."


- anon


How about this that I learned from the Dodge Dakota newsgroup a while
back? Forget about tire pressure for now. Load up the plane to what
you expect to be the normal operating weight. Pump up the tire untill
you get full tread and no sidewall contact. Take the tire pressure and
use that from then on.

How do you know when you've got full tread contact? Pour some water
just in front of the tire and pull the plane through it, letting the
wheel turn completely over a couple of times. It'll leave an 'imprint'
on the second time around that will be a mirror image of the tread
pattern. If you can read sidewall numbers, you need more air. If it is
just a thin strip, you need to remove some.

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber

My pressure recommendations stand. I will now slither
back under my rock.

- anon
++++++++++++++++++++++++++

You anonymous recommendations stand?
Whoopee for you and your rock, brave heart.


Barnyard BOb --

*Barnyard BOb* wrote:

You anonymous recommendations stand?
Whoopee for you and your rock, brave heart.


Barnyard BOb --

You are a foolish foolish man.

- anon

My pressure recommendations stand. I will now slither
back under my rock.

- anon

You anonymous recommendations stand?
Whoopee for you and your rock, brave heart.


Barnyard BOb --

You are a foolish foolish man.

- anon
++++++++++++++++++++

Sorry, pathetic one.
As an anal tight-ass coward...
your words have no weight.

Your rock awaits.
Go for it.


Barnyard BOb --