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Old 03-24-2019, 08:47 PM
E. D. Eliot E. D. Eliot is offline
Join Date: Dec 2005
Location: San Pedro
Posts: 975
Default Rotax warm up ops - your suggestions please

First off, I want to say that this question is posted only to gain answers - not in any way to disparage or be critical of anyone or anything - please understand - I seek info only.

Background - I'm in the early stages of my quest to obtain a Sport Pilot Certificate so that I may fly my RV-12 after completion and certification this year. I'm flying a Sling with a Rotax 912 ULS - pretty much the same engine that the RV-12 uses. Of course, there differences in the FWF install but it looks pretty much the same as the RV-12 install.

Situation - My Flight Instructor and I taxied out to the active runway at 2000 RPM, pulled into the warm-up area, and began the process of waiting for the engine to get up to the mandatory 122 degree temperature prior to take off.

The engine never got above 120 degrees F and then, only briefly as it hovered around the 118 mark. Wind was calm -OAT was about 68 degrees - altimeter was 30.12. Clouds overhead at 2000 - sky broken. Nice sunny day. We kept the RPM at 2000 degrees during the warm up attempt. After more than 1/2 hour, we decided to cancel my flying and I taxied back to the flight club. Please understand - we are not allowed to exceed 2000 RPM until the oil temp reaches at least 122 Degrees F. Water temp got up to 158.

Suggestions please - and thanks.
Building finally
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Old 03-24-2019, 09:38 PM
Mich48041 Mich48041 is offline
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 2,962

Verify the oil temperature via some other means. How about removing the dip
stick and inserting a thermometer or temperature probe in its place?
Joe Gores
RV-12 Flying
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Old 03-24-2019, 09:54 PM
DHeal DHeal is offline
Join Date: Sep 2006
Location: Windsor, California
Posts: 848

At @ 68 degrees F outside temp my RV-12 Rotax 912 ULS engine warms up past 120 degrees OT very nicely. You are allowed to run the engine up to 2,500 rpms during the pre-120 degree OT warm-up period. At only 2,000 rpms it is no surprise that it might take a long time to get a rise in your OT. I suggest that you read the airframe and engine operating manuals applicable to your aircraft -- the information is all there.
David Heal - Windsor, CA (near Santa Rosa)
EAA #23982 (circa 1965) - EAA Technical Counselor and Flight Advisor; CFI - A&I
RV-12 E-LSA #120496 (SV w/ AP and ADS-B 2020) - N124DH flying since March 2014 - 870+ hours (as of Jan 2020)!
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Old 03-25-2019, 03:56 AM
crashley crashley is offline
Join Date: Jun 2009
Location: hazelwood north vic
Posts: 174
Default warmup

I have found that on colder days if I run the engine for a few minutes and then shut it down and let it heat soak for a few minutes then restart i get to the minimum oil temp quicker than just sitting at 2000 to 2500 rpm
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Old 03-25-2019, 04:37 AM
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mike newall mike newall is offline
Join Date: Jan 2005
Location: Yorkshire, England
Posts: 1,850

We have resorted to a blanking plate on the oil cooler and the main radiator.

Much better ops, in flight temps are bang in the middle and you don't need a flask and sandwiches for the warm up
"I add a little excitement, a little spice to your lives, and all you do is complain!" - Q

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Last edited by mike newall : 03-25-2019 at 05:05 AM. Reason: snaps added
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Old 03-25-2019, 07:11 AM
BigJohn BigJohn is offline
Join Date: Nov 2008
Location: Gloversville, NY
Posts: 1,587

What Dave says. Is there a reason you are attempting to warm up at only 2000 RPM? That is little more than an idle.
John Peck, CFII, A&P, EAA Tech Counselor, Flight Advisor.
“Master Pilot” Award, UFO Member.
RV-12 N37JP 120176 Flying since 2012.
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Old 03-25-2019, 07:54 AM
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Piper J3 Piper J3 is offline
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 1,652

I believe your best option is to pre-heat the engine before starting. This is best for the engine and significantly reduces warm-up run time. I have E-Z HEAT 912 engine pre-heater which I control with a cell phone relay switch.

Jim Stricker
Hinckley, Ohio (1OA2)
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
RV-12 E-LSA #120058 AWC July 2012 N633CM
RV-12 Bought Flying Oct 2015 with 48TT - Hobbs now 522

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Old 03-25-2019, 11:07 AM
N456TS N456TS is offline
Join Date: Aug 2017
Location: NC
Posts: 30

68F is a nice day. You should have warmed up fairly quickly. Absolutely no need for preheating. You should be able to warm up in 10 minutes or faster at 32F. I've always found warming up at 1,800 RPM is quicker then at higher RPM. I suspect that will shift based on the specific airframe. You have an instrument issue or some other abnormal problem. You shouldn't need to block the oil cooler off in that warm of weather. I would also take the time to download and read the operator's manual directly from Rotax. It's always good to cross-check anything you have been taught/read/heard. In an S-LSA, the POH overrides it, but it's how Rotax wants you to operate.
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Old 03-25-2019, 11:10 AM
NinerBikes NinerBikes is offline
Join Date: Dec 2018
Location: Granada Hills
Posts: 380

You spent .5 Hr at Zamparini field on the Hobbs Meter, paying $65 to sit there idling and not flying, for your lesson?

OAT not being that cold, I am certain if you'd seen up to 2500 rpm, which you are allowed to do on a cold motor, you'd have seen 122F and the green light on the dash for the temp being OK.

I have seen this same symptom numerous times just 35 miles up the road from you in my friends RV-12 at Whiteman Airport.

Give the engine 2500 rpm in the warm up area until you clear 122F for your oil temperature, then proceed to check the A and B rpm drops at 4000.

I've seen the temp just get stuck at around 118F. 5 to 15 seconds at 2500 rpm seems to get the temp to get at 122F or above, so far, every time, here in Southern California, where we are at, where the temperatures are mild.

Read the Rotax operators manual, 2000 rpm, first 2 minutes, after that time frame, 2500 rpm is allowed, show that to your instructor.

Last edited by NinerBikes : 03-26-2019 at 01:11 AM.
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Old 03-25-2019, 11:11 AM
E. D. Eliot E. D. Eliot is offline
Join Date: Dec 2005
Location: San Pedro
Posts: 975
Default Thank you all

I'll read my engine manual and then show it to my CFI. He was acting as per flight club regulation so well see what the outcome is. Thanks again, ED.
Building finally
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