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Old 05-16-2021, 12:16 PM
EdH's Avatar
EdH EdH is offline
Join Date: Jun 2010
Location: Wiltshire, UK.
Posts: 267

Rotax certified the 916iS last summer, 157hp for 5 mins then 134hp max continuous from sea level to 23,000ft. No fanfare... for a covert client.
RV-3B G-LILB - Ex-N159SJ UK import Sept 2022
RV-3B G-CCTG - Purchased May 2020
RV-8 G-MIRV - Finished July 2019 - sold
RV-6 G-BZRV - Finished July 2002 - sold
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Old 05-16-2021, 08:36 PM
tjo tjo is offline
Join Date: Dec 2009
Location: La Center,wa
Posts: 258

The problem with the Rotax 915 from my perspective:
- weight and balance
- high cost
- could run mogas, but impractical due to on airport availability (or lack of)
- limited or expensive constant speed prop availability
- roll your own FWF package

If you can overcome these, or they are not an issue for you, then do it. Performance should be fine. My choice, though, is a Lycoming.

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Old 05-16-2021, 09:41 PM
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jliltd jliltd is offline
Join Date: Sep 2013
Location: Rancho San Lorenzo
Posts: 1,387

Originally Posted by NinerBikes View Post
Need to add some weight to the nose? Get a constant speed prop for the 915iS
My understanding is that the 915is needs a constant-speed prop to operate properly. It has something to do with how the oil circulates through the crankshaft. At least that was what Rotax stipulated four years ago when the 915is was hitting the real production market. That was one of the "no go" items for USA-based by LSAs as constant speed props ae not allowed. Plus having one could easily have pushed the slicker LSAs past the maximum allowed. Perhaps there has been an accommodation like a crankshaft oil bypass valve for fixed-pitched propellers in the last 4 years.

Jim Ivey
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Old 05-17-2021, 08:30 PM
NordicDave NordicDave is offline
Join Date: Oct 2020
Location: KSNS
Posts: 33

An STC is now available for the Rotax retrofit to a Cessna 150.
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Old 05-17-2021, 09:00 PM
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jliltd jliltd is offline
Join Date: Sep 2013
Location: Rancho San Lorenzo
Posts: 1,387

That's an amazing development for the Cessna 150. A Rotax 915is with constant-speed prop STC. Add a tailwheel conversion to an early model and it would be a great bush plane.
Jim Ivey
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Old 05-18-2021, 05:34 AM
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Major-Tom Major-Tom is offline
Join Date: Jul 2018
Location: Templin (Germany)
Posts: 72

Originally Posted by Diego9 View Post
combination of moving the engine FW and adding some mass in the engine area

A ballistic parashute system would be a nice extra mass for many builders! The european version of the CH650 has ist BRS firewall forward.
D-MDYZ ICP Savannah-S built, flying, sold
D-ERVM RV-12iS #121128 flying since March 2022
RV-14A #141053 endless waiting
PAID...of course
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Old 04-02-2022, 11:32 AM
ccast04 ccast04 is offline
Join Date: Sep 2020
Location: Omaha NE
Posts: 12

I'm sure this has been posted before, but seems like the mothership is thinking the same thing and it works. Would be interested to hear what they have done to fix potential W&B issues.
Chris C.
Private Pilot
RV-9A Emp Ordered - Feb '22/ Rcv'd May '22
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Old 04-03-2022, 04:58 PM
Dreamin9 Dreamin9 is offline
Join Date: Aug 2016
Location: Near Buffalo, NY
Posts: 77

The Rotax engines are a different breed. Might want to be sure you have a local “wrench” who is knowledgeable/experienced in their quirks.

Resale might be an issue, much smaller market for buying a used plane with what many consider, right or wrong, an oddball engine.

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Old 04-13-2022, 12:14 AM
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hpmicrowave hpmicrowave is offline
Join Date: Nov 2007
Location: Fort Walton Beach, FL
Posts: 139
Default Rotax 915is upgrade for RV9 in the works

In a discussion with a reliable source at the end of Sun n Fun this past weekend I was told about an ongoing flight test program with a RV9 and a Rotax915is. The source said the upgraded RV9 can easily keep up with the RV fleet at 9k and above. The conversion package his company is working on will be complete with prop, cowling, and firewall forward and will be brought out soon when all the testing and details are complete.

On the other hand this might just be a Rotax POC working with Vans Aircraft developing the firewall forward design details for the RV15??

From my experience with the 915is I believe it's one, if not the most sophiscated reciprocating aircraft engine available today. It's fully computerized with redundant computer, fuel and ignition systems, turbo charged and inter cooled, gets full power to around 15k, computer will always work to get the most efficient fuel power combination with the single power lever. Burns mogas including ethanol mogas as well as avgas. And uses oil like a modern car engine does. Oil changes every 100 hours using unleaded fuel and 50 hours with leaded avgas. It's not cheap but it's operating costs will make it a good option for many folks.
Cecil "TRON"
RV8 N95CH Flying !!
RV6A Flying with Son Chris
Member, FlyOnSpeed Team
Sling 4 TSI 90% Complete
2022 Dues Paid, Home Field 18FD

Last edited by hpmicrowave : 04-15-2022 at 12:06 AM. Reason: Additional thoughts
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Old 04-21-2022, 04:48 PM
GeoffM GeoffM is offline
Join Date: Dec 2012
Location: Marin, CA
Posts: 3

Updated 9 kit with final-size holes, more pre-fabed parts, updated plans, etc. and the option for a 915is? Sign me up.

That's the RV I'd build. Simplicity of the new kits with modern engine and kit would be amazing.
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