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Pros' & Cons' 912UL vs 912ULS

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dh5465(at)cox.net
Guest

Posted: Wed Jan 09, 2008 6:27 pm Post subject: Pros' & Cons' 912UL vs 912ULS

Speaking of the Rotax 912...........  I have a  newby question.  I don't own a Kitfox yet, and I'm still considering buying  a flying one.  I'm thinking about a model IV with a 912.

  

 What are the Pro's & Con's of the 912UL vs the  912ULS?  Of course the obvious, the 912ULS has 20 more hp.  Are there  any down sides to having the 912ULS?  Is it a HUGE performace difference  between them?   I have run across more 80hp models than 100hp models  forsale.

  

 Thanks,

 Dale Herseth

 Mesa, Az

  

  

  

 [quote]   ---

cliffh(at)outdrs.net
Guest

Posted: Wed Jan 09, 2008 7:14 pm Post subject: Pros' & Cons' 912UL vs 912ULS

I have a model 4 Speedster. When I bought it, it  had a 912 UL. I installed a 912 ULS a couple of years later. 

 The 912 ULS cut my takeoff run by about 100  ft.

 My rate of climb increased by about 400 Ft per  minute.

 The cruise speed is about the same at 105  mph.

 Floran Higgins

 Helena, Mt.

 Speedster

 912 ULS

 [quote]   ---

runwayrex(at)juno.com
Guest

Posted: Wed Jan 09, 2008 7:42 pm Post subject: Pros' & Cons' 912UL vs 912ULS

Dale, 

  The big difference to ME is the fuel. The 80 horse burns unleaded regular while the 100 needs premium. Right now, they're about twenty cents per gallon difference. I'm concerned about a few years from now.  

I also hear from a Rotax repair guy that the S is prone to more problems from the added power. He claims that the UL is smoother, shakes less when starting and stopping and is more "relaxed" when running. But, to each his own, and I'm guessing that others will have different opinions. I have 650 hours on my UL and like it a lot. I've never felt the "need" for more power with my Model 3. My plane weighs 660 empty. I'm interested if I'd still be happy with 80 HP in a Model 7. I've got some research to do. Good luck with your search. 

Rex Phelps in Michigan / Warp Drive 



-- "Dale H" <dh5465(at)cox.net> wrote:

 Speaking of the Rotax 912...........  I have a newby question.  I don't own a Kitfox yet, and I'm still considering buying a flying one.  I'm thinking about a model IV with a 912.

  

 What are the Pro's & Con's of the 912UL vs the 912ULS?  Of course the obvious, the 912ULS has 20 more hp.  Are there any down sides to having the 912ULS?  Is it a HUGE performace difference between them?   I have run across more 80hp models than 100hp models forsale.

  

 Thanks,

 Dale Herseth

 Mesa, Az

  

  

  

 [quote] ---

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Thu Jan 10, 2008 2:44 am Post subject: Re: Pros' & Cons' 912UL vs 912ULS - 3000 hours TBO ?

The cost difference of reg to premium here in Canada is about 10 to 15 cents a litre so that translates into 40 to 60 cents a gallon more. You getting a good deal there Rex   



There are flight schools getting over 3000 hours out of the 912 UL . These are getting regular maintenance and use Rotax oil filters.  Some will tell you different but for 16$ the Rotax filter is a few dollars more than the after-market ones that will fit. BUT , there are many differences including pressure relief valve. The after-market will just open and your oil will not be filtered and you will never know.  There have been cases where the pressure relief spring has actually worn right through the oil filter resulting in a total oil loss.  



One another note on oil and 912s is that  having your oil sender mounted off the engine like on the firewall with a line from the existing sender hole might  make them last longer.  The Diamonds certifieds are done this way.   Also Rotax tried to make them stronger by using a brass band around there as a damper for vibration but firewall mount is the best cure.





 	  Quote: 	
		  Dale, 

The big difference to ME is the fuel. The 80 horse burns unleaded regular while the 100 needs premium. Right now, they're about twenty cents per gallon difference. I'm concerned about a few years from now. 

I also hear from a Rotax repair guy that the S is prone to more problems from the added power. He claims that the UL is smoother, shakes less when starting and stopping and is more "relaxed" when running. But, to each his own, and I'm guessing that others will have different opinions. I have 650 hours on my UL and like it a lot. I've never felt the "need" for more power with my Model 3. My plane weighs 660 empty. I'm interested if I'd still be happy with 80 HP in a Model 7. I've got some research to do. Good luck with your search. 

Rex Phelps in Michigan / Warp Drive 



-- "Dale H" <dh5465> wrote: 

Speaking of the Rotax 912........... ?I have a newby question. I don't own a Kitfox yet, and I'm still considering buying a flying one. I'm thinking about a model IV with a 912. 



What are the Pro's & Con's of the 912UL vs the 912ULS? Of course the obvious, the 912ULS has 20 more hp. Are there any down sides to having the 912ULS? Is it a HUGE performace difference between them? I have run across more 80hp models than 100hp models forsale. 



Thanks, 

Dale Herseth 

Mesa, Az

_________________
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rjdaugh

Joined: 30 Aug 2006
Posts: 195

Posted: Thu Jan 10, 2008 6:49 am Post subject: Pros' & Cons' 912UL vs 912ULS

Might toss out one other thing to think about.  



My strip is at 4400'.   At this altitude the 912S is making about 80 hp.  I

find this preferable to the 64 hp that the 912 makes at this altitude.



Randy

_________________
Randy
Kitfox 5/7 912S
Black Hills, South Dakota

kerrjohna(at)comcast.net
Guest

Posted: Thu Jan 10, 2008 10:24 am Post subject: Pros' & Cons' 912UL vs 912ULS

........and Florin, what about fuel burn?  Seems that there exists a fairly fixed relationship between power and fuel burn.  The relationship between power and speed is exponentially less productive.

  

 Are we chasing absolutes?  What flight profile is desired? Darin is configuring his 7 for the same flight environment as I have for my Classic IV. His resulting profile will likely not vary much from mine because of the difference in weight; 820# vs 640#.

  

 The Saturday before OSH I took off from LGU 4450' in my 160hp RV9 (longer wings) with an RV7 and an RV8 both with 180hp engines. I arrived at cruise altitude about 10 minutes and several miles ahead of them but they soon caught up and passed me.  All three weigh in at 1050+/- pounds.  Design affects performance.

  

 John

  

 [quote]-------------- Original message -------------- 

From: "floran higgins" <cliffh(at)outdrs.net> 

    I have a model 4 Speedster. When I bought it, it had a 912 UL. I installed a 912 ULS a couple of years later. 

 The 912 ULS cut my takeoff run by about 100 ft.

 My rate of climb increased by about 400 Ft per minute.

 The cruise speed is about the same at 105 mph.

 Floran Higgins

 Helena, Mt.

 Speedster

 912 ULS

 [quote] ---

darinh

Joined: 20 Apr 2006
Posts: 327
Location: Utah

Posted: Thu Jan 10, 2008 12:19 pm Post subject: Re: Pros' & Cons' 912UL vs 912ULS

 	  Quote: 	
		   Darin is configuring his 7 for the same flight environment as I have for my Classic IV. His resulting profile will likely not vary much from mine because of the difference in weight; 820# vs 640#. 	




John,



I think our performance envelopes will vary significantly, at least I hope they will...Keep in mind the turbo lets me produce the rated 115 hp up to 10,000' and 100 hp up to 20,000.  So even though I will weigh in close to 200# more than you, my weight to hp is significantly less.  On a standard day (72 degrees, and 29.92) at 4450' you are producing around 84% of your rated power or roughly 67 hp.  At 10,000' its about 64% of rated assuming standard conditions.  That puts you around 9.55 lbs./hp. on the ground and 12.5 lbs./hp at 10k.  On the other hand, I will be producing rated power up to 10k so I am at 7.39 lbs./hp on the ground and 8.5 lbs./hp at 10k.  I've also got he CS prop so that should add to my climb and cruise.  



Somebody check my math but I think this is pretty accurate.  Now, this is not a contest with John by any means, simply an analysis for me to justify the amount of money I have in this project!  I don't want to regret this project if I could have accomplished the same goals for half to 2/3 the costs by going with a Classic IV.  



I flew a model 3 with a 912UL and the performance was great but nothing compared to what Mark Miller is getting in his 914 Series 7.

_________________
Darin Hawkes
Series 7
914 Turbo
Kaysville, Utah

dgolden(at)golden-consult
Guest

Posted: Thu Jan 10, 2008 3:14 pm Post subject: Pros' & Cons' 912UL vs 912ULS

darinh wrote:

 	  Quote: 	

> Darin is configuring his 7 for the same flight environment as I

> have for my Classic IV. His resulting profile will likely not vary

> much from mine because of the difference in weight; 820# vs 640#.

 John,

 I think our performance envelopes will vary significantly, at least I

 hope they will...Keep in mind the turbo lets me produce the rated 115

 hp up to 10,000' and 100 hp up to 20,000.  So even though I will

 weigh in close to 200# more than you, my weight to hp is

 significantly less.  On a standard day (72 degrees, and 29.92) at

 4450' you are producing around 84% of your rated power or roughly 67

 hp.  At 10,000' its about 64% of rated assuming standard conditions.

 That puts you around 9.55 lbs./hp. on the ground and 12.5 lbs./hp at

 10k.  On the other hand, I will be producing rated power up to 10k so

 I am at 7.39 lbs./hp on the ground and 8.5 lbs./hp at 10k.  I've also

 got he CS prop so that should add to my climb and cruise.

That 115 HP is takeoff only (5 min) and I believe that the 100 HP

continues to about 16,000', but that is still significant power at

altitude. I would still like the 914 for my M IV Speedster (I'm from

Colorado originally), but the cost may put it out of the picture.

Dennis

-- 

Dennis Golden

Golden Consulting Services, Inc.

darinh

Joined: 20 Apr 2006
Posts: 327
Location: Utah

Posted: Thu Jan 10, 2008 4:39 pm Post subject: Re: Pros' & Cons' 912UL vs 912ULS

Dennis,



You are correct, it is for 5-minutes but the 912UL and ULS are also only rated for full power for 5-minutes.  You may also be right on the 16,000'.  I need to read through my owners manual to get the exact specs.  The 20,000' reference came from the Pulsar list about 2 weeks ago and I didn't take the time to verify its accuracy.  Even so, 100 hp at 16,000 is more than a non turboed O-360 is generating.



I am also adding the intercooler that Bell intercoolers puts out.  The purpose for this is simply to decrease the temps of the inlet air in hopes that it will prolong the life of the engine.  But an added benefit is that cooler inlet air means a little bit more power.  Only time will tell how it will perform...I am betting it is pretty good.

_________________
Darin Hawkes
Series 7
914 Turbo
Kaysville, Utah

dgolden(at)golden-consult
Guest

Posted: Thu Jan 10, 2008 5:04 pm Post subject: Pros' & Cons' 912UL vs 912ULS

darinh wrote:

 	  Quote: 	
		   

 

 Dennis,

 

 You are correct, it is for 5-minutes but the 912UL and ULS are also

 only rated for full power for 5-minutes.  You may also be right on

 the 16,000'.  I need to read through my owners manual to get the

 exact specs.  The 20,000' reference came from the Pulsar list about 2

 weeks ago and I didn't take the time to verify its accuracy.  Even

 so, 100 hp at 16,000 is more than a non turboed O-360 is generating.

 

 I am also adding the intercooler that Bell intercoolers puts out.

 The purpose for this is simply to decrease the temps of the inlet air

 in hopes that it will prolong the life of the engine.  But an added

 benefit is that cooler inlet air means a little bit more power.  Only

 time will tell how it will perform...I am betting it is pretty good.


	


Is there online information for the Bell intercooler?



-- 

Dennis Golden

Golden Consulting Services, Inc.

cliffh(at)outdrs.net
Guest

Posted: Thu Jan 10, 2008 7:04 pm Post subject: Pros' & Cons' 912UL vs 912ULS

With the 912UL I burned about 4.5 GPH.

 With the 912 ULS I burn about 5 GPH.

  

 Floran Higgins

 Helena, Mt.

 Speedster

  912 ULS

 [quote]   ---

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Thu Jan 10, 2008 9:27 pm Post subject: Re: Pros' & Cons' 912UL vs 912ULS

 	  Quote: 	
		  With the 912UL I burned about 4.5 GPH. 

With the 912 ULS I burn about 5 GPH. 



Floran Higgins 

	


And you said at 105 mph cruise ?   not bad but you could likely see 10 to 15 mph  more . What have you done for fairings etc ? What size tires do you have and what prop are you running ?

cliffh(at)outdrs.net
Guest

Posted: Fri Jan 11, 2008 5:50 am Post subject: Pros' & Cons' 912UL vs 912ULS

It has the plastic fairings on the struts.

It has 8.00X 6 tires. I have removed the wheel pants as they tend to fill up 

with snow.

I have the GSC prop. I know the warp prop is more efficient but I an old 

fashioned enough to like the looks of a wood prop on an airplane with a 

round cowl.

This 105 figure is the GPS reading.



Floran Higgins

Helena Mt.

Speedster

912 ULS

---

darinh

Joined: 20 Apr 2006
Posts: 327
Location: Utah

Posted: Fri Jan 11, 2008 9:04 am Post subject: Re: Pros' & Cons' 912UL vs 912ULS

Dennis,



Try www.bellintercoolers.com

_________________
Darin Hawkes
Series 7
914 Turbo
Kaysville, Utah

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Fri Jan 11, 2008 9:58 am Post subject: Re: Pros' & Cons' 912UL vs 912ULS

 	  Quote: 	
		  It has the plastic fairings on the struts. 

It has 8.00X 6 tires. I have removed the wheel pants as they tend to fill up 

with snow. 

I have the GSC prop. I know the warp prop is more efficient but I an old 

fashioned enough to like the looks of a wood prop on an airplane with a 

round cowl. 

This 105 figure is the GPS reading. 



Floran Higgins 	




Well I like the GSC props too and on 2 strokes they are within a few % of most other props in my testings.  On the 912 though  I think the IVO props can give you more cruise. Seriously you could likely see 10 to 20 mph gain in cruise speed   -- 115 to 125 mph.   



I have several different WARP blades and they are the cats ass for Floatplane ops with the near indestructible  nickel leading edges.  If you notice my youtube videos last week I put up , I said we hit a tree doing "pipe line inspection"  .. it was about 1/2 to 1" around at 100 mph   <snicker>  not a mark anywhere. 

I just ordered some props this week for customers and if anyone looking for WARP this season better get going they are running up to 12 weeks for delivery.

clint_bazzill(at)hotmail.
Guest

Posted: Fri Jan 11, 2008 10:41 am Post subject: Pros' & Cons' 912UL vs 912ULS

I am one of the very first 912ULS Drivers.  Have a Model IV-1200 with orig 912UL with IVO.  At 375 hours changed it out to 912 ULS also with IVO but newer and longer blade.  Zero Plus 72 inch 3 blade.  I have almost 1300 hours and would guess that almost 800 area cross country.  I fly the 912ULS different that the 912UL.  At cruise I used to use full throttle at 5500 and my fuel burn was between 4.1 and 4.2 GPH.  With the 912ULS I use 23 to 24 inches MP and try to keep the RPM'S around 5000 and above 5000 ft always have the throttle back about an inch.  This keeps my fuel burn almost exactly as the 912UL only flying 10 mph faster.  Some changes in landing gear, but the increased compression that gains you 10 hp is free.  Clint

[quote] Subject: Kitfox-List: Re: Pros' & Cons' 912UL vs 912ULS

 From: dave(at)cfisher.com

 Date: Thu, 10 Jan 2008 21:27:19 -0800

 To: kitfox-list(at)matronics.com

 --> Kitfox-List message posted by: "dave" <dave(at)cfisher.com>

 > With the 912UL I burned about 4.5 GPH. 

 > With the 912 ULS I burn about 5 GPH. 

 > 

 > Floran Higgins 

 > 

 And you said at 105 mph cruise ? not bad but you could likely see 10 to 15 mph more . What have you done for fairings etc ? What size tires do you have and what prop are you running ?

 --------

 Rotax Dealer, Ontario Canada

 Flying Videos and Kitfox Info

 http://www.cfisher.com/

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=157395#157395

 ======================

   	  Quote: 	
		  [b]

av8rps

Joined: 05 Jan 2008
Posts: 33
Location: Central Wisconsin

Posted: Mon Jan 14, 2008 6:07 am Post subject: Re: Pros' & Cons' 912UL vs 912ULS

(Dale says "Speaking of the Rotax 912...........  I have a  newby question.  I don't own a Kitfox yet, and I'm still considering buying  a flying one.  I'm thinking about a model IV with a 912.

  

 What are the Pro's & Con's of the 912UL vs the  912ULS?  Of course the obvious, the 912ULS has 20 more hp.  Are there  any down sides to having the 912ULS?  Is it a HUGE performace difference  between them?   I have run across more 80hp models than 100hp models  forsale....")

  

 

Dale,



A really economical way to get the best of both worlds is to buy that 80 hp Model IV and then install the high compression pistons in it that Mastercraft has available for the 912 (I believe Lockwood also sells them now)



Here's a copy of a post off the forum a while back on this subject;



--> Kitfox-List message posted by: "Clifford Begnaud" <shoeless>



> Clint,

> Is it possible to modify the 912UL into a 912 ULS?



I can help with this question...

The short answer is; not entirely.

You can install these high compression pistons and get a nice boost in 

power: http://www.masterkraft.com/



In our first kitfox, we installed these at about 250 hours. The engine and 

pistons now have well over 1000 hours and is still running great. We did an 

overhaul at about 1000 hours because the engine ingested some washers and 

damaged two pistons, but two of the pistons installed at 250 hours are still 

in there. Lockwood said that other than the washer damage, the engine was in 

great shape, showing little if any wear. They even had the Masterkraft 

pistons in stock.

What you won't get with this mod is the different gear ratio used on the 

912ULS. You may not get the full extra 20 hp of the ULS, but you get close. 

On a model 4, it would be awesome!

The only downside that I can think of is that you may get some oil seepage 

from around the rocker covers after several hundred hours. I don't know if 

that was really the fault of the pistons or not, but the fix was for 

Lockwood to resurface the rocker covers. That stopped the leaking. It may be 

that many 912's without the high compression pistons suffer this leakage 

also, I just don't know. (though I have heard of some 80 hp 912's with this 

problem)



I hope this info helps.

Best Regards,

Cliff

Erie, CO

S5, Lycoming 0-235

****** end of original message*****

Paul Seehafer

_________________
Model IV-1200 912ul Amphib
Avid Flyer Sn#1 and Sn#26
Highlander 912s taildragger
Lake Amphibian
Central Wisconsin
paul676@tds.net

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