VansAirForceForums  
Home > VansAirForceForums

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

- Today's Posts | Insert Pics


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

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 08-24-2017, 08:05 AM
WingedFrog's Avatar
WingedFrog WingedFrog is offline
 
Join Date: Mar 2010
Location: Raleigh, NC
Posts: 854
Default A little gem about the Rotax 912

Coming from Mike Busch, a guru on GA engines, this is big!

https://www.youtube.com/watch?v=jOsCBrQMzWY
__________________

Builder's name: Jean-Pierre Bernoux
Sport Pilot
Kit # 120395 N124BX
Flying as of 9/11/2013

Builder's Blog:http://vieilleburette.blogspot.com/
EAA 1114
Reply With Quote
  #2  
Old 08-24-2017, 05:14 PM
waterboy2110 waterboy2110 is offline
 
Join Date: Jul 2010
Location: SF Bay Area
Posts: 164
Default

I would agree with pretty much everything FAA Inspector says in his comment. There are many down sides to this little engine.
__________________
http://jimsrv.blogspot.com
PP - ASEL
Instrument Rating
A&P / Rotax iRMT 9 Series Maintenance
RV12 Flying.
Reply With Quote
  #3  
Old 08-24-2017, 06:02 PM
DaleB's Avatar
DaleB DaleB is offline
 
Join Date: Sep 2012
Location: Omaha, NE (KMLE)
Posts: 1,722
Default

I think if "FAA Inspector" is that concerned, he should probably not buy a Rotax 912 series engine.

The 912 series have been around long enough, and there are enough in production (and flying) that I think if the so-called "downsides" were real issues, we'd be hearing a lot about them. I think there are some real misconceptions "Inspector's" epistle, like his understanding of the alternator and regulator and whether you can design an engine to run reliably at higher RPM than a desk fan. But, as he says, it's all his opinion and everyone is welcome to theirs.

Yes, they are different than Lycomings and Continentals. The overhaul and repair procedures are different. The design philosophy is certainly different. That doesn't mean they are something to regard with fear and trepidation, but if you do, well, by all means go buy an O-200D. For the rest of us, despite their obvious differences from more traditional GA piston engines, it's hard to argue with the demonstrated success over the past few decades.
__________________
Dale
Omaha, NE
RV-12 # 222 N980KM "Screamin' Canary" (bought flying)
Fisher Celebrity (under construction)
Previous RV-7 project (sold)
-=VAF=- 2017 dues paid
Reply With Quote
  #4  
Old 08-24-2017, 06:08 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,024
Default

Decent overview on the 912 engines if a bit long.

Couple points on the video:

The Continental O-200 is not a dry sumped engine, it simply has an odd shaped oil pan.

The maximum boiling point of a water/ EG mix is not reached at 50/50, it's reached at 100% EG 0% water. Evans non-aqueous PG coolant is little different in characteristics from 100% EG coolant but a ton more expensive.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW- 416.6 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 08-25-2017 at 09:25 PM.
Reply With Quote
  #5  
Old 08-24-2017, 06:26 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,024
Default

Quote:
Originally Posted by DaleB View Post
I think if "FAA Inspector" is that concerned, he should probably not buy a Rotax 912 series engine.

The 912 series have been around long enough, and there are enough in production (and flying) that I think if the so-called "downsides" were real issues, we'd be hearing a lot about them. I think there are some real misconceptions "Inspector's" epistle, like his understanding of the alternator and regulator and whether you can design an engine to run reliably at higher RPM than a desk fan. But, as he says, it's all his opinion and everyone is welcome to theirs.

Yes, they are different than Lycomings and Continentals. The overhaul and repair procedures are different. The design philosophy is certainly different. That doesn't mean they are something to regard with fear and trepidation, but if you do, well, by all means go buy an O-200D. For the rest of us, despite their obvious differences from more traditional GA piston engines, it's hard to argue with the demonstrated success over the past few decades.
Well said. The piston speed is not much different between a Lyc 360 at 2700 rpm and a 912 at 5500 rpm. Combine this with similar barrel and piston expansion rates, Nikasil bores and liquid cooled heads which keep the heads well below any temperature where strength may be affected and guess what? They last just fine as Lockwood said.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW- 416.6 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


Reply With Quote
  #6  
Old 08-24-2017, 10:24 PM
Jim T Jim T is offline
 
Join Date: Jan 2005
Location: Independence, OR
Posts: 169
Default

I haven't watched the whole presentation yet, but I wonder if this FAA inspector might be like a lot of motorcyclists that think that Harley Davidson (Lycoming/Continential) is the only "real" motorcycle. After all their design is about the same vintage. And yes I have owned a Harley and I loved it! Along with a lot of the "less vintage" motorcycles that I've owned.

Jim
__________________
RV-12 kit no.: 120647
Working on finish kit
http://www.mykitlog.com/JimT

2006 Rans S-6S Coyote (flying)
Reply With Quote
  #7  
Old 08-24-2017, 11:38 PM
DaleB's Avatar
DaleB DaleB is offline
 
Join Date: Sep 2012
Location: Omaha, NE (KMLE)
Posts: 1,722
Default

Quote:
Originally Posted by Jim T View Post
After all their design is about the same vintage.
Kinda sorta but not really. The general layout may show its heritage, but at least Harley has advanced their technology. Even my 14 year old H-D has electronic fuel injection, and a few years later they started using water cooling in the hot parts of the heads. It's driven by emission requirements. They have to burn leaner and leaner to meet emission regs, and that makes it run hotter and hotter (here we go with that again, right?) and requires better control of mixture and timing. I haven't kept up enough to know if they now run closed loop; mine is open loop.

My pickup is a full size crew cab land yacht that will seat six in glorious comfort and weighs over 2-1/2 tons empty. They manage to get 365 HP out of a 3.5 liter V6 with twin turbos, and the speed limiter is easy to hit if you're, umm, "spirited" with it. Times change. It's been 100.0% reliable with zero repairs or adjustments since the day I bought it new in early 2011. If you'd told me that in the 80s I'd have laughed at you.

The presentation was Mike Bush talking about how, by golly, this new Rotax engine is pretty good. Welcome to 2017, Mike. The other stuff was just some anonymous guy posting his opinions on Youtube.
__________________
Dale
Omaha, NE
RV-12 # 222 N980KM "Screamin' Canary" (bought flying)
Fisher Celebrity (under construction)
Previous RV-7 project (sold)
-=VAF=- 2017 dues paid
Reply With Quote
  #8  
Old 08-25-2017, 09:18 PM
Tommycat's Avatar
Tommycat Tommycat is offline
 
Join Date: Feb 2017
Location: North-western Illinois
Posts: 85
Default Prop drag?

I enjoyed the presentation, thanks for posting. I found it a helpful instructional as to what the Rotax, maintenence, and it's install is about.

But which does create the most drag with a damaged engine? (No power)
A freewheeling prop...or one that's stuck in one position?


Regards,
__________________
T.C.

VAF Supporter
Reply With Quote
  #9  
Old 08-25-2017, 11:17 PM
DaveWelch DaveWelch is offline
 
Join Date: Mar 2005
Location: Huntsville, AL
Posts: 288
Default

Quote:
Originally Posted by Tommycat View Post
I enjoyed the presentation, thanks for posting. I found it a helpful instructional as to what the Rotax, maintenence, and it's install is about.

But which does create the most drag with a damaged engine? (No power)
A freewheeling prop...or one that's stuck in one position?


Regards,
My understanding has been that, although perhaps counterintuitive, the best strategy is to try to get the prop stopped (stalled) if you have a dead engine. Reason is that it takes energy to keep it turning (think of the effort needed to start by hand propping). That energy is coming from the air against the prop (drag) and is stealing your airspeed and altitude at the worst possible time while you're trying to get max glide. Seems like I recall at least one POH that said if no luck restarting, then pull up to slow down in an attempt to let the prop stop. Kind of a twofer, you (might) gain some altitude (don't stall!) and get a better glide after it stops.
__________________
Dave
RV12 N951DZ
First Flight 9/23/16!
No paint yet. Working on a scheme with John Deere colors or accents.
Reply With Quote
  #10  
Old 08-26-2017, 07:27 AM
vic syracuse vic syracuse is offline
Super Moderator
 
Join Date: May 2005
Location: Locust Grove, GA
Posts: 2,032
Default

Yes, I have practiced complete engine out landings in the kitfoxes and RV-12's. Letting the prop come to a complete stop does make a difference in drag, and it's considerable smoother, allowing you to concentrate on the landing.
There is no doubt that the engine is NOT producing power.

Vic
__________________
Vic Syracuse

Built RV-4, RV-6, 2-RV-10's, RV-7A, RV-8, Prescott Pusher, Kitfox Model II, Kitfox Speedster, Kitfox 7 Super Sport, Just Superstol, DAR, A&P, EAA Tech Counselor/Flight Advisor, CFII-ASMEL/ASES
EAA Homebuilt Council Chair/member EAA BOD
Van's East Coast Representative
www.Baselegaviation.com
Reply With Quote
Reply


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 03:32 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.