Home > VansAirForceForums

-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

Go Back   VAF Forums > Model Specific > RV-12/RV-12iS
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Thread Tools Search this Thread Display Modes
Old 11-22-2016, 09:31 PM
RFSchaller RFSchaller is offline
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 2,916


I don't know if a flat would ruin a wheel pant, but I suspect it might. I helped a guy with a tire that went flat in his hangar. We had to jack up the wing just to get to the wheel pant bottom screws to get it off.

The wheel pants look great, but from a practical stand point they don't seem to be worth the expense and maintenance complications. --- And yet mine are still in place. I guess it's like my bad comb over --- looks good to me!😜

Reply With Quote
Old 11-23-2016, 05:47 AM
todehnal todehnal is offline
Join Date: Jan 2005
Location: Kentucky Lakes area in KY
Posts: 947

Thanks John. Desser has both, and the 6 ply is only $5 more, but the 6 ply tires are on a short 7 day waiting period. I guess I will just wait for the 6 ply. My thoughts were that I could run just a bit more pressure, and still retain the cushion with the 4 ply tires. My guess is that the 4 ply would be a tad lighter as well. Appreciate your thoughts.........Tom
2013- RV12, Kit #119. N123M First flight Nov21. It's a keeper!
1998- RV-9 tail kit, built and sold
1989- RV-6 tail kit, built and sold
Reply With Quote
Old 11-23-2016, 06:41 AM
Dave12 Dave12 is offline
Join Date: Oct 2010
Location: Elkton, Md.
Posts: 1,674

Originally Posted by RFSchaller View Post
I guess it's like my bad comb over --- looks good to me!😜

I hear these are becoming fashionable?
Wag Aero Sport Trainer built,sold and wrecked
N588DF RV12 #336 built, sold and alive and well in New York
N73DF RV12 #244 built, sold and alive and well in Florida
N91 RV RV9 I wish I could say I built this one! Mark Santoleri hit the ball out of the park on this gem.
Reply With Quote
Old 11-23-2016, 08:32 AM
Piper J3's Avatar
Piper J3 Piper J3 is offline
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,230

Originally Posted by Dave12 View Post
I hear these are becoming fashionable?
I didn't know Alec Baldwin flew a 12...
Jim Stricker
EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 633

LSRM-A Certificate 2016 for RV-12 N633CM
Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father & CFI) - USAAF 1st Lt. Captain B-17H
Reply With Quote
Old 11-24-2016, 08:51 AM
n82rb's Avatar
n82rb n82rb is offline
Join Date: Jan 2007
Location: fort myers fl
Posts: 991

Just a little thinking here, pressure sensor, Bluetooth module, now to get it to talk to the dynon and garmin units..... fun project to work on on overnights......

Bob burns
Rv-4 n82rb
Reply With Quote
Old 11-24-2016, 08:59 AM
JPalese's Avatar
JPalese JPalese is offline
Join Date: Apr 2011
Location: KHXF
Posts: 143
Default RV-12 Maintenance Manual on Tires

[quote=Jetguy;946169]I recently put on my third set of main tires at 632 hrs. I thought I would
try something new and changed from the Desser Aero Classic All Weather tire to the Desser Elite retreads.


Page 5-8 of the maintenance manual (Rev 4) specifies "All three tires are 5.00 x 5 size, either 4-ply or 6-ply tube type aircraft tires are acceptable."
John Palese
1) AAL Captain & Check Airman (ret)
2) USAF LtCol & Command Pilot (ret)

2) Adjunct Professor-Aviation Science
3) MKE FSDO FAAST Lead Rep & Remedial Trainer.

RV-12 Transition Training, Rental & Instruction.
RV-6/6A, RV-7/7A, RV-9/9A transition training
RV-7 Transition Training LODA.
Drone Detection & Counter-measures
Reply With Quote
Old 11-24-2016, 11:58 AM
DanH's Avatar
DanH DanH is offline
Join Date: Oct 2005
Location: 08A
Posts: 9,797

My go-to reference for aircraft tires is the Michelin Aircraft Tire Databook. Most of what is found there will apply to other brands in the same sizes. I winnowed the little chart below for 5.00-5 main tires.

Note that inflation pressures may be adjusted downward in proportion to load. For example, a 5.00-5 4-ply has a 31 psi max pressure when unloaded. Max static load is 800 lbs per tire. If we assume 90% of the load is on the mains, an RV-12 at 1320 lbs would load each tire...

(1320 x 0.9) / 2 = 594 lbs


(594 x 31) / 800 = 23 psi minimum pressure to achieve design spec, which is mostly a matter of how much the tire can compress before the rim and bead mash into the carcass. See the "bottoming load" values.

For an RV-12 at 1320 lbs, a 4 ply rating is more than enough. An 1800 lb airplane could maybe use the 4 ply rated tire, but it would be right at the maximum allowable load...

(1800 x 0.9) / 2 = 810 lbs

and thus would need a slight boost in tire pressure:

(810 x 31) / 800 = 31.3 psi

A 6 ply tire on an 1800 lb airplane can run an unloaded tire pressure as low as....

(810 x 50) / 1285 = 31.5 psi minimum pressure to achieve design spec

Note that minimum pressures for both 4 and 6 ply are (as a practical matter) the same, given the same load. That's not a coincidence; they're dimensionally the same. The difference is burst pressure (maximum strength, if you will), not operating pressure.

Remember two details. First, these are unloaded pressures. Add 4% for rated load.

Second, these are tire manufacturer's numbers. An airframe designer or wheel engineer may specify something different for reasons of their own, and as an EAB operator, you also have a say. For example, as Scott noted recently, a higher than specified tire pressure may increase airframe component load, given a maximum smash into the runway. A landing gear analysis says running tire pressure at max (for example, a 6-ply at 50 psi) does in fact increase component load, but the actual difference is not large. Me? I'll take the higher pressure and try not to crash into the runway with maximum gusto.

Dan Horton
Barrett IO-390

Last edited by DanH : 11-24-2016 at 07:17 PM.
Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -6. The time now is 02:23 PM.

The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.