Sabaru vs Rotax 912 UL

[Bartman1959 12]

I keep hearing how much heavier the Subaru is than the Rotax, but I haven't seen any actual numbers.  Does anyone know the actual weight difference in the two engines?

Edited 16 Aug 2018 by Bartman1959

[TJay 1041]

http://www.aeromomentum.com 

I would also like to see one of these fly I bet it would beat the soob 

[Bartman1959 12]

http://www.aeromomentum.com 

I would also like to see one of these fly I bet it would beat the soob 

With the same horse power but lighter weight, I'm sure it would beat the soob.  But, what is their reliability like?  What is the cost of repairs like? Can you take one to your favorite auto mechanic to have it rebuilt?  How much is the FWF kit?

[Yamma-Fox 403]

My NSI manual listed my old Subaru E81 at 225 lbs (total FWF weight).  I never weighed it myself but am pretty sure they wouldnt have overestimated it.

[Bartman1959 12]

My NSI manual listed my old Subaru E81 at 225 lbs (total FWF weight).  I never weighed it myself but am pretty sure they wouldnt have overestimated it.

Thanks, I appreciate the info.

[Av8r3400 1179]

After parting out a buddy's Subaru powered Kitfox, the weight of his setup was closer to 260#. 

I don't know the brand of the conversion, but it used a Ford planetary gearbox.

[Bartman1959 12]

Thanks for the info Av8r3400.

[Allen Sutphin 705]

My NSI/Subaru weighted 235 lbs when I removed it for the new owner. That's flying weight with all fluids. The 912 actually comes in at about 215 flying weight and that's the 912ULS. Everybody kinda underestimates the flying weight or don't add the extras that are required. As far as performance, depends on what phase you are talking about. Take-off roll, climb ability, top speed, etc. Reliability relies more on proper maint and operation than the engine.  I don't care what the book says, you hoist a 0-200 Cont off a C-150 and it will bump about 260 lbs. A long way from the 198 lbs per the book. Horsepower is another misquoted figure that's thrown around a lot. An 0-200 for example is only pushing about 85-90 hp since they dropped the timing from 28 deg back to 24 deg to save cracking the heads.  Most horsepower ratings are for a new engine, at max power with a min pitch prop or club prop. We have had the wool pulled over our eyes about horsepower ratings for many, many years.  Horsepower numbers is what sells engines.

[Bartman1959 12]

My NSI/Subaru weighted 235 lbs when I removed it for the new owner. That's flying weight with all fluids. The 912 actually comes in at about 215 flying weight and that's the 912ULS. Everybody kinda underestimates the flying weight or don't add the extras that are required. As far as performance, depends on what phase you are talking about. Take-off roll, climb ability, top speed, etc. Reliability relies more on proper maint and operation than the engine.  I don't care what the book says, you hoist a 0-200 Cont off a C-150 and it will bump about 260 lbs. A long way from the 198 lbs per the book. Horsepower is another misquoted figure that's thrown around a lot. An 0-200 for example is only pushing about 85-90 hp since they dropped the timing from 28 deg back to 24 deg to save cracking the heads.  Most horsepower ratings are for a new engine, at max power with a min pitch prop or club prop. We have had the wool pulled over our eyes about horsepower ratings for many, many years.  Horsepower numbers is what sells engines.

Thanks for the info Allen, I appreciate it.  20 lbs doesn't seem like a lot of additional weight for the massive price difference. 

[wypaul 448]

Can't speak for others but my 912 comes in at about 160 lbs ready to roll out the hangar and ready to fly fluids included. 

[Yamma-Fox 403]

Yeah I think most 912 I've heard are more in that 160 lb area..  FWF minus radiator.

That question comes up a bit with people looking into Yamaha (which come in around 175 lbs FWF).

 

[lv2plyguitar 172]

I replaced my 582 with a 912 uls.  The 582 had a lot more weight in terms of mounts and stuff than the 912.  The 912 is a cleaner install.  When I picked up the 582 off the ground with everything attached firewall forward it felt heavier than the 912 firewall wall forward.  My CG did not change.  I recently purchased the zipper kit and that decreases the 912 weight by 4 lbs as well.

 

[Av8r3400 1179]

My NSI/Subaru weighted 235 lbs when I removed it for the new owner. That's flying weight with all fluids. The 912 actually comes in at about 215 flying weight and that's the 912ULS. Everybody kinda underestimates the flying weight or don't add the extras that are required. As far as performance, depends on what phase you are talking about. Take-off roll, climb ability, top speed, etc. Reliability relies more on proper maint and operation than the engine.  I don't care what the book says, you hoist a 0-200 Cont off a C-150 and it will bump about 260 lbs. A long way from the 198 lbs per the book. Horsepower is another misquoted figure that's thrown around a lot. An 0-200 for example is only pushing about 85-90 hp since they dropped the timing from 28 deg back to 24 deg to save cracking the heads.  Most horsepower ratings are for a new engine, at max power with a min pitch prop or club prop. We have had the wool pulled over our eyes about horsepower ratings for many, many years.  Horsepower numbers is what sells engines.

I don't know what you are including to get 215 pounds for a 912.  Maybe with a prop, engine mount, all fluids, battery and a sand bag you can get there.  165-175 with radiator, exhaust and fluids is realistic for a ULS.  198 is what Continental advertises their lightweight O200-D at, not the "standard" O200-A.

Engines are a very personal choice.  There are plenty of Subaru's flying.  They work, no argument.  It's all what you want.

 

[Bartman1959 12]

"Engines are a very personal choice.  There are plenty of Subaru's flying.  They work, no argument.  It's all what you want."  That is a very true statement Av8r3400.  I'm not looking to be a "Flying Cowboy," I'm just wanting to get into a KF 5 at an affordable price, for me, and to be able to afford the upkeep on the airplane on my retirement income.  Thanks for all the info guys, I appreciate it.

[Allen Sutphin 705]

Engine weights are like most things, they are up for debate. I really don't care what a 912 weighs. I don't care for them and probably will never own one.  A good engine from what everybody says, a bit pricey, but I can't put a 20K+ engine on a 8K airframe to fly 50 or so hours a year. If you fly 100-200 hrs a year, it makes a little more sense.  I don't work on 912's and it has cost me a little business which I no longer want anyhow.  I will on occasion, tinker on a Taylorcraft or Champ, or EXP just to keep refreshed and the A&P license oiled. But hey, its America, your free to use whatever engine you choose.

[Bartman1959 12]

Allen, I absolutely agree with you.  Although I'm not an A&P, an auto mechanic, or any other kind mechanic, I do know how to wrench on engines, I do have a good grasp on what makes these airplanes fly.  I don't have tons of money, but being retired, I do have tons of time.  With all that being said, I think the Subaru is the way to go for me.

[nlappos 413]

My 670 puts out at least 92 HP, and it added a total of 20 lbs to my 582 Mark IV, engine, prop, belly radiator and Highhwing gear, all  actual flying weight. And it cost a bunch less than a 912, $3400 and a turn in of the 582 to Rotax Rick.

[PW_SD 1]

My 670 puts out at least 92 HP, and it added a total of 20 lbs to my 582 Mark IV, engine, prop, belly radiator and Highhwing gear, all  actual flying weight. And it cost a bunch less than a 912, $3400 and a turn in of the 582 to Rotax Rick.

You have me curious about the 670. Do you have a link to any posts on the improvements you have found and what the conversion from the 582 involved? Thx.

[nlappos 413]

 I posted a bunch, with photos at :   http://www.avidfoxflyers.com/index.php?/topic/5734-new-rotax-670-install/

[wypaul 448]

Allen just curious what you are putting in your plane to replace the NSI.  I am guessing not a new O-200 due to the cost. 

[Allen Sutphin 705]

Either a Hirth 3202 55 HP two-stroke or depending on the weight of the airframe, a 3002 Hirth 80 HP two-stroke (probably used low time). The 3202 is around 98 lbs RTF and the 3002 is 138 lbs RTF.  But due to the power/torque curve of the 3002, it'll leave a 912 eating dust. (The advantage of a two-stroke, instant power when you throw the juice to it.)  The 3002 runs a little smoother due to 4 opposed cylinders.  Of course, unless a 150 HP engine that burns 2.5 GPH and weighs 100LBS comes along, but I am not holding my breath.

[Bandit 286]

Engine weights are like most things, they are up for debate. I really don't care what a 912 weighs. I don't care for them and probably will never own one.  A good engine from what everybody says, a bit pricey, but I can't put a 20K+ engine on a 8K airframe to fly 50 or so hours a year. If you fly 100-200 hrs a year, it makes a little more sense.  I don't work on 912's and it has cost me a little business which I no longer want anyhow.  I will on occasion, tinker on a Taylorcraft or Champ, or EXP just to keep refreshed and the A&P license oiled. But hey, its America, your free to use whatever engine you choose.

I agree, I would never spend that kind of money on a engine installation when you could buy a T-craft or Chief for $15000 or a nice Champ for a few thousand more. Most people don't  fly 60 hours a year.  

[wypaul 448]

It is nice that we have different options to fit our needs.

[Yamma-Fox 403]

It is nice that we have different options to fit our needs.

I count our freedoms in the EAB world high among those that we still have left!

You imagine it...  create it...  fly it.

And if you think about it, there's not really a lot of oversight or regulation hancuffing or confining us.

I think that is so damn awesome!!

Funny though how some people are appalled by the thought of things not being regulated or limited and are just beside themselves in angry attempts to take freedoms away from others.  Really pisses me off.

OK...  hijack and rant over.

[BryceKat 125]

Allen,

Your the first person I’ve known to ever consider a hirth! Do you have experience with them? Are they good?  I’d love to look into a Hirth, but have yet to find anyone that has positive experiences with them. Thanks, Bryce