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Rotax vs UL Power

J

johnr9q

Member
I know that the UL Power engine is not supported in the RV-12 (why not - that really isn't my question but an aside question) what other information should I use to compare the engines if I wanted to install one in a CH 650? (Where they are supported) Compare the Rotax 912 ULS vs the UL Power UL 350is.
The following are what I have discovered:
1. The Rotax is $2092 cheaper
2. The UL Power has fuel injection
3. The UL Power has 30 more HP
4. The Rotax is a more proven engine (Many more out there)

What other things am I missing?

I am not a pilot but am interested in home built. I live near Sacramento (any partners out there)
 
I am in the process of building a RV-12 with the UL260is.
The guys in the hanger next to me built a CH650 about two years ago and installed the UL with 130 hp and love it. It has about 230 hours on the engine and they are very happy with it.
It can get to pattern altitude or higher by the end of the runway.
If you would like more info you can contact Robert Helms who is in charge of the US division.
He is great to talk with and get help

[email protected]
 
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johnr9q said:
What other things am I missing?
Click to expand...

It may not be the case now (and I may be remembering incorrectly since it was more than 8 years ago now), but during initial RV-12 development, I think the configuration of the UL engine at that time was that it was aircraft power system dependent for ignition and fuel injection operation (I.E. could not produce its own power to continue running in the event of an aircraft electrical system failure.
This can be over come with additional electrical system design, but statistics show that it still induces more opportunity for failures caused within the system and by the operator (higher complexity).
 
The ROTAX seems to be a tough little engine, and some of the issues like sensor failures and VR failures seem pretty minor flaws in a reliable power plant. Some guys enjoy experimenting during their builds, so I can see why they might want to try another engine as a challenge, but I doubt there is an option that supplies the balance of performance and reliability that makes it clearly superior o the 912 ULS. I just wanted to complete my plane with the minimum hassle, so the stock 912 ULS seemed the hands down choice.
 
Wikipedia says "Rotax produced its 50,000th 912-series engine in 2014"

In the same line as the Canadians saying:
"Eat Caribou, 10,000 wolfs cannot be wrong"
I would be inclined to say:
"Install a 912, 50,000 pilots cannot be wrong"

;)
 
The UL also has more power output on its alternator.

Although I hear there is a 40 amp alternator you can add that is belt driven to the Rotax.

Bob
 
The UL turns its propeller at shaft speed, I think, rather than gearing it down like the Rotax does. A slower-turinng prop is more efficient, and that might affect the long-term fuel usage.

Dave
 
UL Power RV12

We installed the 260iS in our RV12 almost 3 years back. We have very satisfied with this power plant. Yes the 30 amp stock alternator can run the engine. We pull 18 to 20 amps during normal operation. UL does have other alternator options available. A Firewall Forward package is now available contact Robert Helms for details. Aircraft Wicks has taken over the sales of ULPOWER spares.
 
rvbuilder2002 said:
It may not be the case now (and I may be remembering incorrectly since it was more than 8 years ago now), but during initial RV-12 development, I think the configuration of the UL engine at that time was that it was aircraft power system dependent for ignition and fuel injection operation (I.E. could not produce its own power to continue running in the event of an aircraft electrical system failure.
This can be over come with additional electrical system design, but statistics show that it still induces more opportunity for failures caused within the system and by the operator (higher complexity).
Click to expand...

Since I think info shared by others here on VAF should be backed up by data and personal experience, not here-say.... the same applies to me.

I finally got a chance to research a bit (as anyone considering any engine instead of the 912 for their RV-12), and do a memory refresh.

The engine driven alternator on the UL engines has an output of 30 amps, but ~15 amps of that capacity is required for the power used by the ignition and fuel injection systems. That leaves ~ 15 amps for aircraft systems.

Using info available on the UL engine web site, it is not possible to determine if the engine will run on it's own if the aircraft electrical system has to be shut down for some reason but based on other info that is on the web site, I think it would not.
They do have info regarding a test they did to simulate an alternator failure. Based on that test data, the engine will run for about 1 hour on a battery equiv. to what we use in the RV-12 (16 Ah battery with an approx. 15 amp draw from the engine systems). That is assuming you shut off all other electrical equipment. Anything left on will reduce the time to engine stoppage depending on the current draw of the device.

Another interesting fact is that other than the 97 HP version of the engine, the minimum fuel octane (using the U.S. standard of RON+MOM/2) is 93.5. 93.5 AKI auto fuel is not readily available here in the U.S which means you would have to use avgas ( the 97 HP engine can use 91 Oct.)

Because the UL 260 engine is direct drive it will not have the same prop efficiency as the 912. To get the same level of thrust as the Rotax you would have to use an engine slightly higher in HP. The 107 HP version would probably get somewhat close, but that is higher compression so requires the use of avgas 100% of the time. The only other option would be the low compression 6 cyl UL350i which is 118 HP. It could use premium auto fuel but is more expensive, and weighs 13 lbs more than the 912.

The recommended TBO for all the UL engines (except aerobatic model) is 1500 hrs compared to the 912 at 2000 hrs.
.
 
No Mogas, no thanks.:p I just went and bought 110 gallons of premium at $2.45 per gallon non ethonal. :D After my fixed cost, insurance & hangar rent. Fuel is my biggest expense.;)
 
UL Power - Robert Helms... the UL Guy

Hi everybody,

A Van's owner suggested I join this forum to respond to the posts. I'll scroll through them and answer to the best of my ability.

We believe in choices. There are many choices. We are just one of the choices. Our sales style is "consultative." We will give you advise about your choices but we are not forceful and not offended if you chose another engine.

The first subject I was asked to address is the fuel requirement. All of our engines can use automotive gas with up to 15% ethanol. On our "i" model you can use 91 octane. On the "iS" model, because of the higher compression you should use 93 octane. You can use 100LL but the lead is not good for the engine so you should add decalyn, TCP, Marvel Mystery Oil, etc. to deal with the lead.

Some have commented about the literature saying 95 or 98 octane... this is the standard in Europe that converts to our 91 and 93 (we use the AKI method and they use ROM or RON).

Feel free to post more questions on here or email to me at [email protected].

Regards,
Robert
 
Welcome to VAF!

Robert,
welcome.gif
aboard the good ship VAF.

Great to have you here, always nice to have folks from the industry to keep things accurate.
 
rhelms said:
Hi everybody,

A Van's owner suggested I join this forum to respond to the posts. I'll scroll through them and answer to the best of my ability.

We believe in choices. There are many choices. We are just one of the choices. Our sales style is "consultative." We will give you advise about your choices but we are not forceful and not offended if you chose another engine.

The first subject I was asked to address is the fuel requirement. All of our engines can use automotive gas with up to 15% ethanol. On our "i" model you can use 91 octane. On the "iS" model, because of the higher compression you should use 93 octane. You can use 100LL but the lead is not good for the engine so you should add decalyn, TCP, Marvel Mystery Oil, etc. to deal with the lead.

Some have commented about the literature saying 95 or 98 octane... this is the standard in Europe that converts to our 91 and 93 (we use the AKI method and they use ROM or RON).

Feel free to post more questions on here or email to me at [email protected].

Regards,
Robert
Click to expand...

Robert,
I think I am the only one that has posted in this thread about octane requirements, and I didn't say anything about 95 or 98. A posted that the requirement for teh lower compression models was 91 AKI and 93.5 AKI for the higher compression.
So thanks for affirming the octane requirement info I posted.
The web site says that the higher compression engines require 93.5 AKI. So you are saying 93 AKI is close enough? A slight problem with that is 93 is not readily available everywhere (not here where I live in the pacific north west anyway ).

Can you confirm whether the UL engines will continue to run if the aircraft electrical system has to be shut down? Or whether an independent power source needs to be designed / isolated from the main aircraft system?
 
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UL Power - Alternator

Hi rvbuilder2002,

I'm not sure if I'm "responding" correctly but I'll give it a shot.

Rotax makes good engines. We are not in competition with Rotax. We are just another choice.

We have an optional 50 amp alternator if 30 amps is not enough. We also have a dual 15 amp alternator if you want two alternators.

The alternator has magnets so you can indeed shut down the battery and the engine will continue to run.

The 350 series engine is a 4 cylinder; not a six.

You don't "need" 100LL for any of our engines. They will all run on 100LL but automotive gas is preferred. The "i" model uses 91 octane. The "iS" uses 93 octane.

A longer slower turning prop does typically provide more thrust at slow airspeeds but a lot more drag at higher airspeeds. It all depends upon the goal of your plane. Do you want STOL or cruise? The RV12 with the UL260iS performs about the same as that stated on the Van's website.

With respect to TBO... it's just a recommended number. We encourage prospective buyers to talk to owners, service centers, etc. What's nice about our engine is you can pull the pan off in about 15 minutes and do a real good visual inspection of the inside of the engine. If the compression is good, oil analysis is good, visual inspection is good.... keep on flying.

I hope this helps.

Regards,
Robert Helms
UL Power


rvbuilder2002 said:
Since I think info shared by others here on VAF should be backed up by data and personal experience, not here-say.... the same applies to me.

I finally got a chance to research a bit (as anyone considering any engine instead of the 912 for their RV-12), and do a memory refresh.

The engine driven alternator on the UL engines has an output of 30 amps, but ~15 amps of that capacity is required for the power used by the ignition and fuel injection systems. That leaves ~ 15 amps for aircraft systems.

Using info available on the UL engine web site, it is not possible to determine if the engine will run on it's own if the aircraft electrical system has to be shut down for some reason but based on other info that is on the web site, I think it would not.
They do have info regarding a test they did to simulate an alternator failure. Based on that test data, the engine will run for about 1 hour on a battery equiv. to what we use in the RV-12 (16 Ah battery with an approx. 15 amp draw from the engine systems). That is assuming you shut off all other electrical equipment. Anything left on will reduce the time to engine stoppage depending on the current draw of the device.

Another interesting fact is that other than the 97 HP version of the engine, the minimum fuel octane (using the U.S. standard of RON+MOM/2) is 93.5. 93.5 AKI auto fuel is not readily available here in the U.S which means you would have to use avgas ( the 97 HP engine can use 91 Oct.)

Because the UL 260 engine is direct drive it will not have the same prop efficiency as the 912. To get the same level of thrust as the Rotax you would have to use an engine slightly higher in HP. The 107 HP version would probably get somewhat close, but that is higher compression so requires the use of avgas 100% of the time. The only other option would be the low compression 6 cyl UL350i which is 118 HP. It could use premium auto fuel but is more expensive, and weighs 13 lbs more than the 912.

The recommended TBO for all the UL engines (except aerobatic model) is 1500 hrs compared to the 912 at 2000 hrs.
.
Click to expand...
 
rhelms said:
Hi rvbuilder2002,

I'm not sure if I'm "responding" correctly but I'll give it a shot.

Rotax makes good engines. We are not in competition with Rotax. We are just another choice.

We have an optional 50 amp alternator if 30 amps is not enough. We also have a dual 15 amp alternator if you want two alternators.

The alternator has magnets so you can indeed shut down the battery and the engine will continue to run.

The 350 series engine is a 4 cylinder; not a six.

You don't "need" 100LL for any of our engines. They will all run on 100LL but automotive gas is preferred. The "i" model uses 91 octane. The "iS" uses 93 octane.

A longer slower turning prop does typically provide more thrust at slow airspeeds but a lot more drag at higher airspeeds. It all depends upon the goal of your plane. Do you want STOL or cruise? The RV12 with the UL260iS performs about the same as that stated on the Van's website.

With respect to TBO... it's just a recommended number. We encourage prospective buyers to talk to owners, service centers, etc. What's nice about our engine is you can pull the pan off in about 15 minutes and do a real good visual inspection of the inside of the engine. If the compression is good, oil analysis is good, visual inspection is good.... keep on flying.

I hope this helps.

Regards,
Robert Helms
UL Power
Click to expand...

Robert,
Thanks for the clarification regarding the type of alternator installed (perm. magnet that will run the engine independently).

And it sounds like 93 is ok, even though the UL web site says 93.5 (I realize it is a small difference, but still a difference)
 
While designing my electrical schematic and integrating with existing Vans systems, I was made aware that the factory (UL) underrates the dual 15 amp alternators by about half. (Unsure why they choose to do this) They do propose the proper wiring size for the 30 amp rating. The actual numbers from factory testing is

Rpm | output(V) | output(Amps) | output( Watt)
-------------------------------------------------------------------
| gen 1 gen 2 | gen 1 gen 2 | gen 1 gen 2
1050 | 12.1 12.2 | 7.8 7.3 | 94 89
1200 | 12.4 12.3 | 11.7 12.1 | 145 148
1500 | 12.5 12.7 | 18.9 19.0 | 236 241
1800 | 12.8 13.1 | 23.5 23.7 | 300 311
2100 | 13.2 13.6 | 26.0 26.8 | 343 364
2400 | 13.5 13.8 | 27.9 29.0 | 377 400
2700 | 13.7 14.0 | 29.4 30.6 | 402 428
3000 | 13.8 14.1 | 30.4 31.7 | 419 446

I have chosen to install a more efficient rectifier/regulator, experimenting with two types, that should offer higher voltage at all RPM until max voltage output is attained. However, amperage will suffer slightly from these listed numbers.
 
skydiverlv said:
While designing my electrical schematic and integrating with existing Vans systems, I was made aware that the factory (UL) underrates the dual 15 amp alternators by about half. (Unsure why they choose to do this)
Click to expand...

On their web site it says the standard alternator is rated at 30 amp output, but that ~15 amps of that is used to operating the ign. and fuel injection systems.
 
Ul Power

We have ran our engine with just the Alternator successfully on the ground for 5 minutes.
With sky view 10" and their Transponder, aero led strobes Icom radio and landing light we.see 20 to 22 amps. Without the landing light it drops to about 18 to 20 Amps.
 
UL Power

With all do respect to the over 50,000 rotax flyers. Some of them are my friends. Keep in mind, There are now 50,000 more carburetors in the air and 1,000,000 less carburetors on the ground. I am always amazed and amused by the "proven reliability" comments of old engine technology.
I am willing to bet that pilots who religiously defend the fifties carbureted engine technologies for their rliability, would not consider for a minutes driving (or let their wives/kids) a car with such old technology. Yet, they are willing to fly in one.
UL Power has been flying in Europe for as long as Rotax been flying in the states.
I have one installed on my aircraft and I will never consider anything else.
The 30 amp alternator is more than enough for a modern aircraft. My v6 UL390is engine draw less than 10 amps. turning on every instrument and light in my plane draw less than 15 amps including the engine ECU/Ignition.
The UL Power guys and their engineers would be very happy to help you design and fabricate a mount for your RV.
Check them out.
 
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Which airplane?

myaghi said:
..........UL Power has been flying in Europe for as long as Rotax been flying in the states.
I have one installed on my aircraft and I will never consider anything else.
The 30 amp alternator is more than enough for a modern aircraft. My v6 UL390is engine draw less than 10 amps. turning on every instrument and light in my plane draw less than 15 amps including the engine ECU/Ignition.
The UL Power guys and their engineers would be very happy to help you design and fabricate a mount for your RV.
Check them out.
Click to expand...

Mike, I'm strongly considering a UL for my -12 and a friend of mine is a rep for them. He told me that they already have a FWF for the -12.

What airplane do you have the UL engine in?

Best,
 
myaghi said:
With all do respect to the over 50,000 rotax flyers. Some of them are my friends. Keep in mind, There are now 50,000 more carburetors in the air and 1,000,000 less carburetors on the ground. I am always amazed and amused by the "proven reliability" comments of old engine technology.
I am willing to bet that pilots who religiously defend the fifties carbureted engine technologies for their rliability, would not consider for a minutes driving (or let their wives/kids) a car with such old technology. Yet, they are willing to fly in one.......
Click to expand...

Please, come on! There appears to be an implication that carbs are dangerous. You wouldn't allow the family to drive a carb equipped car? Really?

Okay, fuel injection might be more efficient (by a percentage) but carbs were never replaced because of them being dangerous.

Personally, I consider non-electric carbs and self-generating ignition systems a more comfortable option in a light aircraft than electronic FI and an ignition system that relies on a working alternator/battery system.
 
myaghi said:
UL Power has been flying in Europe for as long as Rotax been flying in the states.
Click to expand...

I think you're being a bit loose with the facts. First UL to fly in Europe was in 2006, if this factory posted info is correct. The first 912 was produced 26 years ago. Hard to believe it took until 2006 for the first one to show up in the US.

EAA Experimenter did an article on UL Power engines 3 years ago.

Tony
 
The UL information is pretty biased.
I know very few unhappy Rotax users and in ratio to the amount in the field many unhappy UL users.
Support is pretty poor and very sloppy on SB's, whilst we live at a two hour drive from the factory.
I know at least two users who kicked it out of their plane having less than 500 hours.

To me based on track record and oerformance alone the choise is obvious.
I am not always happy with the sync requirements of the carbs but powerless operation without electronics is a definite pro.
 
UL Warning

Hotscam, you are more correct than you realize. From experience as a UL Power owner, the vast majority of published information concerning UL power engines is biased. It's always best to do research on both sides of the fence before spending thousands.
 
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