Tire pressure monitor

[Phil King]

Has anyone tried using a tire pressure monitor cap in place of a regular
dust cap on a glider tire?

There are at least two types - simple pneumatic ones that show
green/amber/red or ones with wireless technology to display remotely.

I'm thinking the simple one would be really useful provided it will fit
within the wheel fairing. I think it would be a non-starter for most
glider tail wheels but probably OK for the main wheel.

I would appreciate any constructive advice about this especially from
someone who has tried it.

[[email protected]]

Phil, do a quick search for TPM. There are good threads with info from 2008 and again in 2017.
I tried three different version and while they worked ok most of the time, all three systems would lose the signal at times.

[AS]

On Sunday, August 11, 2019 at 10:07:27 AM UTC-4, wrote:
> Phil, do a quick search for TPM. There are good threads with info from 2008 and again in 2017.
> I tried three different version and while they worked ok most of the time, all three systems would lose the signal at times.

Michael - I think Phil is talking about this style:

https://www.amazon.com/Pressure-Monitor-Valve-Sensor-Indicator/dp/B071K8R6P8/ref=asc_df_B071K8R6P8/?tag=hyprod-20&linkCode=df0&hvadid=242055650048&hvpos=1o4&hvnetw=g&hvrand=3478731346319408487&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9010627&hvtargid=pla-456066788116&psc=1

and not the RF style which would monitor all of your vehicle's and trailer's tires remotely.

Uli
'AS'

[Phil King[_2_]]

At 14:07 11 August 2019, wrote:
>Phil, do a quick search for TPM. There are good threads with info
from
>2008 and again in 2017.
>I tried three different version and while they worked ok most of the
time,
>all three systems would lose the signal at times.

The only threads I found were about trailer tires rather than glider
tires. Anyone any experience of using a monitor on a glider tire?
Phil King

[Ken Fixter[_3_]]

At 13:31 13 August 2019, Phil King wrote:
>At 14:07 11 August 2019, wrote:
>>Phil, do a quick search for TPM. There are good threads with info
>from
>>2008 and again in 2017.
>>I tried three different version and while they worked ok most of the
>time,
>>all three systems would lose the signal at times.
>
>The only threads I found were about trailer tires rather than glider
>tires. Anyone any experience of using a monitor on a glider tire
>Phil King
>
> Just a thought if the tyre deflates in flight knowing that fact
>will it help on landing, you will know what the vibration and >noise is
about.
>KF

[bumper[_4_]]

On Tuesday, August 13, 2019 at 6:45:05 AM UTC-7, Phil King wrote:

>
> The only threads I found were about trailer tires rather than glider
> tires. Anyone any experience of using a monitor on a glider tire?
> Phil King

The problem with most TPMS systems, at least as they might be applied to a glider main tire, is they screw onto the tube's valve stem. In the limited number of gliders I've owned, there is no clearance for them.

I have them on my motorhome and can monitor the glider trailer as well. In that application they make a lot of sense as both tire pressure and temperature are displaced and have set points to trip an alarm. Then I can pull over, check things, and hopefully make necessary repairs before tire pieces depart.

The potential advantage for a glider seems about nil to me. In the unlikely event you have a leaking tire, you are going to land with it anyway, one way or another. You are probably not going to roll the emergency vehicles in any case, so the only advantage would be knowing you've got a low tire or flat in advance. Given that unlikely eventuality (I've only ever had a tailwheel go flat), it doesn't seem like a TPMS would be worth the bother, even if the sensor did have clearance to fit.

Once had a brake caliper freeze to the rotor on my Husky after playing in the snow off road. I knew about it as the Husky veered off a fair amount on take off from the snow covered road and I glanced at the wheel to see it wasn't turning, basically a ski. Landed back home on the unpaved runway at Minden on one wheel, when the locked-up wheel came down it broke free without fuss.

[Phil King[_2_]]

I guess I've not made it clear why I would want a TPM on a glider tire.
My thought is that when checking the glider before flight one action
should be to check the tire pressures. This is a time consuming process
- find pressure gauge, maybe find extension, take off dust cap, fit
gauge (and extension), read pressure, (remove extension,) replace
dust cap, repeat for each tire (three tires on some types). Each time
you do this you remove some air from the tire and with a small tire this
can be significant.

Much simpler to look at the TPM and check that it is showing green!

For a glider I can't see any advantage in having the wireless sort with a
read out in the cockpit. Of course for a trailer it's a great idea.

[Martin Gregorie[_6_]]

On Wed, 14 Aug 2019 08:31:30 +0000, Phil King wrote:

> Much simpler to look at the TPM and check that it is showing green!
>
A search on "tyre pressure monitor cap" shows that shops on Amazon UK
sell them - a four-pack costs less than GBP 2.00. They look as though
they are a bit fatter and longer than the brass tyre caps on my glider,
but at the price its probably worth trying them, even if they do end up
on your car or trailer.


--
Martin | martin at
Gregorie | gregorie dot org

[Phil King[_2_]]

At 11:17 14 August 2019, Martin Gregorie wrote:
>On Wed, 14 Aug 2019 08:31:30 +0000, Phil King wrote:
>
>> Much simpler to look at the TPM and check that it is showing green!
>>
>A search on "tyre pressure monitor cap" shows that shops on Amazon
UK
>sell them - a four-pack costs less than GBP 2.00. They look as though
>they are a bit fatter and longer than the brass tyre caps on my glider,
>but at the price its probably worth trying them, even if they do end up
>on your car or trailer.

Thanks Martin.

There are several different types on the market. I was looking for
anyone with experience of using them on gliders who could save me the
time required to try different ones and find a good one. I've actually
bought some rather more expensive ones off eBay (3 quid each).
Some of the cheap ones have had very bad reviews because they don't
seal well and let the air out of the tyre. If anyone is interested to know

how I get on then I can post the results back here in a few weeks time.

[Dan Marotta]

I believe you are over complicating this.Â* My advice:Â* Just look at the
tires.Â* You can tell if they're too low to fly.Â* That's worked for me
for almost 50 years.

On 8/14/2019 7:45 AM, Phil King wrote:
> At 11:17 14 August 2019, Martin Gregorie wrote:
>> On Wed, 14 Aug 2019 08:31:30 +0000, Phil King wrote:
>>
>>> Much simpler to look at the TPM and check that it is showing green!
>>>
>> A search on "tyre pressure monitor cap" shows that shops on Amazon
> UK
>> sell them - a four-pack costs less than GBP 2.00. They look as though
>> they are a bit fatter and longer than the brass tyre caps on my glider,
>> but at the price its probably worth trying them, even if they do end up
>> on your car or trailer.
> Thanks Martin.
>
> There are several different types on the market. I was looking for
> anyone with experience of using them on gliders who could save me the
> time required to try different ones and find a good one. I've actually
> bought some rather more expensive ones off eBay (3 quid each).
> Some of the cheap ones have had very bad reviews because they don't
> seal well and let the air out of the tyre. If anyone is interested to know
>
> how I get on then I can post the results back here in a few weeks time.
>

--
Dan, 5J

[[email protected]]

I once took off OK but the glider's main tire was totally flat when I landed. Surprise! Rollout was very short. Must have hit some sharp object in the air?

I've had problems with the tire leaking over months, 3 tubes & valves later it seems solved. Whew! With fixed gear and a wheel fairing covering the rim, checking the pressure is a chore. Of course I can look at the tire once the full glider weight is on it, even bounce the wingtips up and down, although with the stiff tire I used to have that was not sufficient to detect partial loss of tire pressure.

[Phil King[_2_]]

At 14:19 14 August 2019, Dan Marotta wrote:
>I believe you are over complicating this.Â* My advice:Â* Just look at the

>tires.Â* You can tell if they're too low to fly.Â* That's worked for me
>for almost 50 years.

Not so easy to check by looking at the tire on the nose wheel of a two
seat glider such as a Grob Twin II or Duo. And main wheel tires often
look OK until you load them up with pilot and water ballast.

[Martin Gregorie[_6_]]

On Wed, 14 Aug 2019 08:19:20 -0600, Dan Marotta wrote:

> I believe you are over complicating this.Â* My advice:Â* Just look at the
> tires.Â* You can tell if they're too low to fly.Â* That's worked for me
> for almost 50 years.
>
Dan, that's not often quite so easy on a grass field, especially as I
have a strong suspicion that grass on a UK glider field is somewhat
thicker and lusher than it might be in NM.

>> how I get on then I can post the results back here in a few weeks time.
>>
Phil, I'd be interested to see what you find out.

I was thinking only yesterday that, after all the rain we've had
recently, it was getting hard to see if there was still a tyre on my main
wheel, let alone how much air was in it. There is very little space
between the bottom of the open wheelbox doors and the grass tops.


--
Martin | martin at
Gregorie | gregorie dot org

[JS[_5_]]

On Wednesday, August 14, 2019 at 8:30:05 AM UTC-7, Phil King wrote:
> At 14:19 14 August 2019, Dan Marotta wrote:
> >I believe you are over complicating this.Â* My advice:Â* Just look at the
>
> >tires.Â* You can tell if they're too low to fly.Â* That's worked for me
> >for almost 50 years.
>
> Not so easy to check by looking at the tire on the nose wheel of a two
> seat glider such as a Grob Twin II or Duo. And main wheel tires often
> look OK until you load them up with pilot and water ballast.

Agree with Dan, just look at them!
In my experience, the nose wheel on a Duo never touches the ground unless you have the CG wrong. Two pilots and chutes with no tail ballast will often do it.
Perhaps 99% of flats are on rigger, tail wheel, tail dolly and wing wheel.... all thin walled. Tost 400x4 and similar mains are pretty thin walled too.
Try Mr. Tuffy or similar material (an old cut up inner tube is better than nothing) on the other wheels.
Look for a high quality main wheel tire and tube. 500x5 seems the easiest to find these for. The beefiest example I've used:
Goodyear Flight Custom 3 with Michelin Airstop tube. Aircraft Spruce has them.
But check if the FC3 fits with the gear retracted!
Jim

[Bob Kuykendall]

On Wednesday, August 14, 2019 at 1:45:05 AM UTC-7, Phil King wrote:

> This is a time consuming process - find pressure gauge...

Any sort of thing you add to the valve stem increases complexity and potential failure points and reduces reliability. In some situations that approach pays off. I think this is not one of them.

My advice: Fill the tire with an air chuck that has a gauge at the beginning of the season, while the glider is standing on it. When you do that, look at how much it bulges at the bottom. As long as the tire looks about like it did when you filled it, it probably is about right.

--Bob K.

[Dan Marotta]

Well, ya got me there... :-D

On 8/14/2019 10:23 AM, Martin Gregorie wrote:
> Dan, that's not often quite so easy on a grass field, especially as I
> have a strong suspicion that grass on a UK glider field is somewhat
> thicker and lusher than it might be in NM.

--
Dan, 5J

[krasw]

On Wednesday, August 14, 2019 at 7:39:56 PM UTC+3, Bob Kuykendall wrote:
>
> My advice: Fill the tire with an air chuck that has a gauge at the beginning of the season, while the glider is standing on it. When you do that, look at how much it bulges at the bottom. As long as the tire looks about like it did when you filled it, it probably is about right.
>
> --Bob K.

This is what most probably would do (me included). However, it's impossible to see if you have pressure little bit on low side. Flight manual tire pressure is not maximum number, it is THE recommended pressure. Tube chafes with tire if pressure is short of this. Enough pressure and you really do not suffer from flat tires, at least that is my experience.

[Jim White[_3_]]

Lessons what I have learned: Never check the tyre pressure on the way to a
competition grid. Pump if obviously low and dangerous but otherwise leave
well alone.

In 2005 I did check the pressure at the 15s. Tyre went down and could not
be re-inflated as valve was jammed. Valve could not be replaced. Had to
replace the entire wheel. Got to the start, landed out in a penalty zone
took 500 point penalty. Altogether a bad day!

Jim

[[email protected]]

"If it ain't broke, fix it until it is."

[Steve Koerner]

As it turns out, I just recently addressed this issue for the JS3 tailwheel.. The retractable tailwheel is quite small. The air volume is such that any attempt to put a gauge on it will drop the pressure quit a lot. Also being so small, I found it hard to judge by eye.

The method I came up with uses a machinist outside caliper to measure tire bulge. It's easily understood with these pictures:

https://photos.app.goo.gl/uyt8BgJWRSKKHuj6A

There's a certain skill required to use the machinist caliper -- the key is zero spring pressure. Accuracy is about 5 PSI.

I was able to accomplish the calibration without any reference to dimensional measurements (inches or mm).

Since this was just devised a couple weeks before the OP came on with his question, it hasn't had much field testing. We'll see if this is a good solution after I've used it awhile.

[Eric Greenwell[_4_]]

Steve Koerner wrote on 8/15/2019 4:59 PM:
> As it turns out, I just recently addressed this issue for the JS3 tailwheel.. The retractable tailwheel is quite small. The air volume is such that any attempt to put a gauge on it will drop the pressure quit a lot. Also being so small, I found it hard to judge by eye.
>
> The method I came up with uses a machinist outside caliper to measure tire bulge. It's easily understood with these pictures:
>
> https://photos.app.goo.gl/uyt8BgJWRSKKHuj6A
>
> There's a certain skill required to use the machinist caliper -- the key is zero spring pressure. Accuracy is about 5 PSI.
>
> I was able to accomplish the calibration without any reference to dimensional measurements (inches or mm).
>
> Since this was just devised a couple weeks before the OP came on with his question, it hasn't had much field testing. We'll see if this is a good solution after I've used it awhile.

Clever! But, are there solid tire wheels that could replace the pneumatic one? Or
get it filled with foam?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

[Steve Koerner]

> Clever! But, are there solid tire wheels that could replace the pneumatic one? Or
> get it filled with foam?
>

I know some owners have talked about having the tailwheel foamed. I don't really know if foam is good enough or not. A key function of the tailwheel tire is to protect the structure against hard impacts. Spring and damping dynamics of foamed tires certainly differ from air. I'm willing to make little design deviations like that only when I'm personally very sure that there won't be adverse consequences.

[Bob Kuykendall]

On Thursday, August 15, 2019 at 4:59:03 PM UTC-7, Steve Koerner wrote:
> The air volume is such that any attempt to put a gauge on it will drop the pressure quit a lot.

One of the best real-world application of the Observer Effect I've heard of in a while.

--Bob K.

[Dan Marotta]

Another application of Heisenberg's Uncertainty Principle.

On 8/16/2019 10:35 AM, Bob Kuykendall wrote:
> On Thursday, August 15, 2019 at 4:59:03 PM UTC-7, Steve Koerner wrote:
>> The air volume is such that any attempt to put a gauge on it will drop the pressure quit a lot.
> One of the best real-world application of the Observer Effect I've heard of in a while.
>
> --Bob K.

--
Dan, 5J

[Eric Greenwell[_4_]]

Steve Koerner wrote on 8/16/2019 9:09 AM:
>
>> Clever! But, are there solid tire wheels that could replace the pneumatic one? Or
>> get it filled with foam?
>>
>
> I know some owners have talked about having the tailwheel foamed. I don't really know if foam is good enough or not. A key function of the tailwheel tire is to protect the structure against hard impacts. Spring and damping dynamics of foamed tires certainly differ from air. I'm willing to make little design deviations like that only when I'm personally very sure that there won't be adverse consequences.

A flat tail wheel has different dynamics, too :^)

Perhaps the tail mount is designed to absorb the energy and crumple before the
structure? I'd contact the factory with a list of substitutes (foamed, solid
rubber/urethane, etc) you'd like use, and get their blessing. I suggest a
polyurethane scooter wheel, which are available in several sizes, and work well
with the ASH 26 E steerable tail wheel, based on the owners' group experience:
strong and good shock absorbing.


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

[Steve Koerner]

On Friday, August 16, 2019 at 1:15:10 PM UTC-7, Eric Greenwell wrote:
> Steve Koerner wrote on 8/16/2019 9:09 AM:
> >
> >> Clever! But, are there solid tire wheels that could replace the pneumatic one? Or
> >> get it filled with foam?
> >>
> >
> > I know some owners have talked about having the tailwheel foamed. I don't really know if foam is good enough or not. A key function of the tailwheel tire is to protect the structure against hard impacts. Spring and damping dynamics of foamed tires certainly differ from air. I'm willing to make little design deviations like that only when I'm personally very sure that there won't be adverse consequences.
>
> A flat tail wheel has different dynamics, too :^)
>
> Perhaps the tail mount is designed to absorb the energy and crumple before the
> structure? I'd contact the factory with a list of substitutes (foamed, solid
> rubber/urethane, etc) you'd like use, and get their blessing. I suggest a
> polyurethane scooter wheel, which are available in several sizes, and work well
> with the ASH 26 E steerable tail wheel, based on the owners' group experience:
> strong and good shock absorbing.
>

Eric, Quite sure the factory isn't interested in blessing a chinese scooter wheel when the design presently calls for an aircraft wheel with aircraft tire. Anyway, there's no actual problem with the present wheel that I know of, so I haven't a motive for pursuing an alternative. The challenge of measuring air pressure is a small matter and hopefully I've got that put to bed.