VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


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

Reply
 
Thread Tools Search this Thread Display Modes
  #21  
Old 03-16-2017, 07:40 AM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 5,516
Default

I am sure Petehowell has posted this on VAF, but here is a link (access Dec2013) to his graph of 100LL and mogas mix. Also, note his test apparatus for Reid Vapor pressure. This should be of interest for those flying with a fuel system without tolerance to high vapor pressure fuels. Carry some test equipment and know your temp/altitude limits.

The RV drivers need to know what the limits are for the fuel/fuel system combination. It is just too risky "hoping" it is ok. Especially if locked into using mogas.
__________________
Bill

RV-7
Lord Kelvin:
“I often say that when you can measure what you are speaking about,
and express it in numbers, you know something about it; but when you
cannot measure it, when you cannot express it in numbers, your knowledge
is of a meager and unsatisfactory kind.”
Reply With Quote
  #22  
Old 03-16-2017, 07:42 AM
rgmwa rgmwa is offline
 
Join Date: Feb 2010
Location: Perth, Western Australia
Posts: 1,647
Default

Quote:
Originally Posted by David-aviator View Post
At that time the Hodges tester was sold by Petersen with the mogas STC kits for various engines..... In fact I believe he stopped selling the tester, maybe because of liability issues....
I understand that general reductions in the volatility of US fuels resulted in reduced demand for the testers to the point where Petersen decided to send their remaining stock back to Dr Hodges in Australia.
__________________
rgmwa
RV-12LR 912ULS
120346
Reply With Quote
  #23  
Old 03-16-2017, 07:57 AM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 5,766
Default

I've seen some boiling point comparisons of winter mogas and some were as low as 105F at SL- lower at several thousand feet. Food for thought on a warm engine with heat soaked carb float bowls.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 441.0 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm


Reply With Quote
  #24  
Old 03-16-2017, 08:15 AM
rvbuilder2002's Avatar
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
Default

Quote:
Originally Posted by Piper J3 View Post
It?s not the seasonal vapor pressure blend of the auto fuel, but rather the residual heat after engine shutdown that causes the fuel to boil off in the carburetor float bowls as I described in my post #10.
Actually it is both.

The vapor pressure of the fuel definitely has an influence and is a variable so operators need to keep it in mind in warmer temps in the spring early summer.
Particularly with specialty fuels (non ethanol) that could have a low sales volume and have been sitting in the retail tank for quite a while.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #25  
Old 03-16-2017, 08:20 AM
rvbuilder2002's Avatar
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
Default

Quote:
Originally Posted by DonFromTX View Post
IF using Decalin or TCP, does that mean you can change oil at non leaded intervals, and none of the bad things from lead will happen to your engine?
No, the same leaded fuel maint. intervals are recommended regardless of whether you use a lead scavenging additive or not.

BTW, use of 100LL doesn't cause any "bad things" to happen with a Rotax, but if you are looking for something to push the Viking higher on the "benefits" chart I guess this might be one. Though with so few engines in service, does anyone actually know what the long term (many hundreds of hours) effects of 100LL is on a Viking installation?
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #26  
Old 03-16-2017, 09:00 AM
David-aviator David-aviator is offline
 
Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
Default

Quote:
Originally Posted by rgmwa View Post
I understand that general reductions in the volatility of US fuels resulted in reduced demand for the testers to the point where Petersen decided to send their remaining stock back to Dr Hodges in Australia.
Robert,

Is the Hodges test kit available in Australia?
__________________
RV-12 Build Helper
RV-7A...Sold #70374
The RV-8...Sold #83261
I'm in, dues paid 2019 This place is worth it!
Reply With Quote
  #27  
Old 03-16-2017, 09:05 AM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 5,766
Default

Quote:
Originally Posted by rvbuilder2002 View Post
BTW, use of 100LL doesn't cause any "bad things" to happen with a Rotax...
Oil change intervals are reduced using 100LL and Rotax techs tell me that gearboxes on engines using 100LL are pretty gunked up with lead, even with the shorter oil drain intervals.

Lead isn't good for a Rotax but the characteristics of the 100LL fuel itself is superior in hot and high conditions from vapor lock formula consistency perspectives.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 441.0 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm


Reply With Quote
  #28  
Old 03-16-2017, 09:24 AM
LettersFromFlyoverCountry's Avatar
LettersFromFlyoverCountry LettersFromFlyoverCountry is offline
 
Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
Default

The one negative about having to go from an IO-360 to the Rotax in the RV-12 I'm building is having to go back to a carbureted engine.
__________________
Bob Collins
St. Paul, MN.
Blog: Letters From Flyover Country
RV-12iS Powerplant kit
N612EF Builder log (EAA Builder log)
Reply With Quote
  #29  
Old 03-16-2017, 09:26 AM
LettersFromFlyoverCountry's Avatar
LettersFromFlyoverCountry LettersFromFlyoverCountry is offline
 
Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
Default

Quote:
Originally Posted by AZLeeJay View Post
Thanks for the info Bob, I think I'll add a little 100LL next time I add some gas. Do you know when they change to the summer blend here in Az?
Although I have a friend here who works at the local refinery and gives me heads up (I'm in MInn), the best way to know when they've switched to the summer blend is when your car picks up about 4-5 mpg on a tank.
__________________
Bob Collins
St. Paul, MN.
Blog: Letters From Flyover Country
RV-12iS Powerplant kit
N612EF Builder log (EAA Builder log)
Reply With Quote
  #30  
Old 03-16-2017, 09:34 AM
Piper J3's Avatar
Piper J3 Piper J3 is offline
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,065
Default

Very good conversations here. Thanks for chiming in Scott...
__________________
-
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 622

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
Reply



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 04:34 AM.


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.