Lycoming vs Continental in a SS 7 ??

[southwind32]

I asked this a few weeks ago, on the engine forum, but thought I'd put it here to see if I could get a little more feed back.
First off, I know most go with the Rotax engines, nothing against the Rotax, but I'm old school and prefer a Lyc or a Cont.
So my question is, O-200 or Lyc O-235 (or other Lyc size) which is better, preferred, best or whatever for the Kitfox SS 7.
Pros and cons are greatly appreciated.
Thanks
Brian

[Av8r3400]

They will all perform well.

I'd look at weight as a major deciding factor. The Lycoming O-235 is heaviest, but makes a little more power, with the Continental O200 and Lycoming O-233 very close to one another.

There are some Continental IO-240s on the forum. These make even more power at the penalty of some more weight.

And of course now we have some Lycoming 320 and 340s going into Kitfoxes...

[southwind32]

I think the Io-240's are out, just because they are so few, and the O-233 is very rare also. I don't want to go to a bigger engine, then is typically used, so I think generally I'm looking at an O-200 or O-235. Another reason is I'm going to be buying a used low time or a core for overhaul, I can't afford a brand new engine.

[dcsfoto]

I went with the Rotax 912iS as I saved $8000
and the FWF Package is more complete.

David Kelm

[Blain]

They will all perform well.

I'd look at weight as a major deciding factor. The Lycoming O-235 is heaviest, but makes a little more power, with the Continental O200 and Lycoming O-233 very close to one another.

There are some Continental IO-240s on the forum. These make even more power at the penalty of some more weight.

And of course now we have some Lycoming 320 and 340s going into Kitfoxes...

What mods if any are needed to hang a -320?

[SS7Flyer]

A Cessna 172 flies good on a 320.. A Kitfox that was designed to weigh in at 700lbs empty not so much. Why ruin a perfectly good airplane with a giant boat anchor on the nose? 1940's technology doesn't belong on modern day experimentals when there are so many other reliable options out there that offer much more performance. With literally 10's of thousands of Rotax motors out there I still can't figure out why people aren't on board. A light weight 912 powered fox will literally fly circles around one with lead in the tail and a anchor up front and burn half the fuel.

[efwd]

We prefer airplane sound instead of snowmobile sound. But when I flew it I didnt really hear it the same way. Noise cancelling headsets do work effectively and I had to heed advice of many that the performance and economy was great and I agreed so Rotax it was.
Eddie

[Esser]

I don't know if you guys have seen the teaser clip that John McBean posted on Facebook on July 19 of the Speedster flyby but I think that pretty much puts the nail in the coffin for the argument that it doesn't sound like a plane.

[efwd]

I dont have facebook! Aargh.

[jrthomas]

SS7Flyer hit the nail on the head. Hang an O200 or an O235 on a Kitfox and loose performance, loose half your rate of climb, add a bunch to your take off roll and see the load you could have carried with a 912 disappear. But it'll sound like a real airplane. I like the sound of the old engines too but the 912's are 10 time more efficient. I can't think of a single area where the 912's are not superior. I wonder if those 1st Mustang and Spitfire pilots complained that their water cooled, geared Merlins didn't sound like an R2800. Don't let the sound bother you. You'll be spoiled to its smoothness and economy. James Thomas

[southwind32]

From my research the Rotex 912 installed weighs about 150lbs, the ContO-200 with accessories weighs about 220lbs, so it appears there's about a 70lbs difference give or take a little.
As far as fuel burn, again, research shows, basically no difference. Both engines come in about 4.5 gallons per hour........again give or take a little.
As far as adding weight in the tail for the Cont, seems most compensate by relocating the battery, so no need to add addition lead weight.
Rotax @ 150 lbs @ 100hp = 1.5php (php= pounds per horsepower)
Cont @ 220lbs @ 100hp = 2.2 php
Cont @ 220lbs @ 125hp (high comp pistons, port and polish) 1.76 php
I plan on 125hp for my O-200 with above mods.
So in summary, fuel burn difference is minimal and not a factor for me.
The difference in weight is a consideration, but factor in the hp mod I plan on doing and the difference in pph isn't much, certainly not enough to cut the rate of climb in half and double the take off distance.
From what I've read, the Rotax has come a long ways as far as reliability and TBO. It's great that many of you love your Rotax's, I have no problem with that.............I just would prefer a Cont or Lyc, and I'm leaning more towards the Cont...............not here to start the great debate which is best............just looking for opinions and experience with the Lyc and Cont powered SS7's
With that said, I do appreciate everyone's input.
Brian

[airlina]

Hi Brian, Nice well educated post on your engine research. The beauty of homebuilding is that you build the airplane you want and are comfortable with. There are some wild exaggerations on some of the previous posts by the Rotax camp. I have a Continental IO-240 in my Series 5 that I have flown happily for 14 years and 800 hours . While it is certainly true that my empty weight is heavy at 950 lbs, the airplane performs great. Climb rate at a mid weight is 1200 fpm , takeoff distance off a grass strip 350' , cruise at 120 mph if I am trying to get somewhere, and if I am flying for the sake of it fuel burn is 4.5 gph (6 gph if trying to get somewhere.) I still have 600 lbs of useful load above my empty weight and I have never been limited with passenger and baggage. (a testament to the kitfox design) So I guess what I am trying to say is listen to all (some with a grain of salt) then do what is right for you. Put this guy in the happy with his heavy continental column. Bruce N199CL

[DesertFox4]

Rotax 912 uls weighs 124.5 lbs.
Add overload clutch. +. 3.7 lbs. ( not installed in early 912 uls engines now standard)
Add exhaust. +. 8.8 lbs. ( rarely included in weight comparisons)
Add airbox. +. 2.8 lbs. ( not installed on majority of 912 uls engines)
Add engine mount. 4.4 lbs. ( rarely included in manf. engine weights)
Total =. 144.2 lbs.

Optional equipment:

Add external alt. 6.6 lbs. ( rarely needed on a Kitfox)
Total = 150.8 lbs

You can see we just hit the previously mentioned weight of 150 lbs. including a few items never listed in engine weights advertised by manufacturers.

Rotax needs a coolant radiator yet and most times a small oil cooler with related plumbing for both. Obviously the Continental and Lycombings need some of the same above items but not all. Engine fluids are not included in the above weights. Oil content in the Rotax is 3.2 quarts. Coolant not possitive but not much more than a gallon total. Maybe less. Someone will know exact quantities.

What ever engine you chose , enjoy making your Kitfox the way you envision it. Remember, the factory supports more engine choices than any other kit aircraft in history. The most versitile kit going. Soon the 915 Rotax will be added to that list. Just get a kit and mount your favorite engine to the front and start building lifelong memories.

[jiott]

Yes, I am solidly in the Rotax camp so my biased opinion is: Nearly all this discussion has been about weight and performance, but I don't think nearly enough has been said about many other high tech factors which I consider very important. Gearbox clutch which protects against prop strikes; Water cooling which keeps engine temps steady in optimum range; Modern close tolerance design which uses essentially no oil between changes; Ability to use Mogas at about $1 per gallon savings; No need for carb heat or mixture control; By far the quietest and smoothest engine out there-I fly occasionally in a friends Super Cub with a Lycoming and find the cockpit noise and vibration to be far above my Rotax. Every passenger I ever take comments on the quiet vibration free ride; Very inexpensive automotive type spark plugs (have you priced out Lyc/Cont plugs lately); Electronic ignition comes standard; Built-in generator so no external alternator/belts/pulleys required on most Kitfoxes; Cabin heat with a small heater core-no danger of CO leakage and exhaust heat muffs that crack; probably a few more that I have missed. Many of the above items may tend to be overlooked by someone who is evaluating engine choices.

[Danzer1]

Pounds per hp of the engine alone is of minimal consequence. To be realistic, you need to look at pounds per hp of the total package. Lets say your normal loaded weigh is 1000lbs with a 912uls at 150lbs. The 912uls continuous hp (5500rpm) is 93hp. Matter of fact the Rotax hp chart for the ULS doesn't even reach 100hp at 5800rpm for the 5 min. max. stated.

1000/93=10.75 lb/hp

Go to a Cont. at 220 lbs (+70lbs) and 100 hp and you have:
1070/100=10.7 lb/hp

Go to a Cont. at 220 lbs (+70lbs) and 125 hp and you have:
1070/125=8.56 lb/hp

I'm still in the UL Powwer camp personally!

YMMV, Greg

[jmodguy]

Brian,
Go with what you know/like/feel comfortable with.
The Rotax is a good engine but has it's own issues, i.e. carb sync, expensive rubber replacement every 5 yrs, expensive ignition modules etc. Some guys have these figured out and do good preventive maint. Some don't.
For what its worth you can equip a Lycoming or Conti with electronic ignition and fuel injection (flyefii.com) and have a lot of the same "benefits" of a Rotax. No mixture, uses automotive spark plugs etc etc. The system cost is similar to buying a couple mags plus gears spacers, spark plugs etc and a carb. Yes its a little more complex than mags but the engine will run smoother and start easier. Also there's no 500 hour mag overhaul requirement (not that many do it), The Rotax built in alternator is limited in capacity and expensive to upgrade. You can add an external alt but be prepared to pay heavy just for the mount.
Are the Lyc/Conti engines heavier than a Rotax? Yup. Easy to work on? yup. Lots of people out there with experience on these engines also.
As for fuel burn, I personally don't care if my KF has a 6 hour endurance because I can't sit for that long.

[southwind32]

Thanks Jeff, and everyone else for your comments. I use to fly 500 hours in 6 months. but the last few years I flew for fun in my Super Cub, I was averaging about 50 hours a year..........I'm 67 and if I fly 5 yours a year for the next 10 years, I'll be well into my 70's...........so probably won't reach that 500 hr mag overhaul LOL.
I like simplicity..........that's another reason I like the Cont. I've worked on a lot of O-200 and although I wouldn't attempt an overhaul, I do feel comfortable on doing a lot of various maintenance on them. I've also have several thousand hours sitting behind them, and not one has ever let me down......literally. :)
Thanks again, for your input.
Brian

[jmodguy]

Good luck Brian! The O-200 is a solid engine and pretty darn reliable. Nothing wrong with KISS methodology!!

[PapuaPilot]

FYI the 500 hour inspection mentioned on the magnetos is not an overhaul, it is just an inspection. I can do a 500 hour inspection on a set of mags in 2-3 hours. The mechanic opens the mag up and and inspects all of the internals. Personally I don't remove the condenser or coil unless there is a good reason. If nothing is bad with the points, condenser, impulse coupling, etc. then the only parts that are replaced are a cotter pin and the woodruff key (which holds on the drive gear or impulse coupling). This inspection can get expensive if there are problems with the impulse couplings, bearings or rotor; or corrosion/pitting of parts. Sometimes the points/condenser need to be replaced, but that isn't too expensive.

And yes, these engines are very easy to work on.

[n85ae]

I'm with Bruce, I've got an IO-240, I'd say the negatives against it are from
people who haven't flown one, my airplane flies great, and performs very
well. Plus it doesn't sound like it's powered by Cox.

I think the weight argument, is also something that comes from not having
flown one either. I've never felt my airplane was nose heavy, or didn't feel
light an nimble. I fly a Super Decathalon some times, and the IO-240 Fox
makes the Super Decathalon feel like a dump truck

However, ANY of the mainstream engines are a good choice, it's really a
matter of money and preference.

Jeff



Hi Brian, Nice well educated post on your engine research. The beauty of homebuilding is that you build the airplane you want and are comfortable with. There are some wild exaggerations on some of the previous posts by the Rotax camp. I have a Continental IO-240 in my Series 5 that I have flown happily for 14 years and 800 hours . While it is certainly true that my empty weight is heavy at 950 lbs, the airplane performs great. Climb rate at a mid weight is 1200 fpm , takeoff distance off a grass strip 350' , cruise at 120 mph if I am trying to get somewhere, and if I am flying for the sake of it fuel burn is 4.5 gph (6 gph if trying to get somewhere.) I still have 600 lbs of useful load above my empty weight and I have never been limited with passenger and baggage. (a testament to the kitfox design) So I guess what I am trying to say is listen to all (some with a grain of salt) then do what is right for you. Put this guy in the happy with his heavy continental column. Bruce N199CL

[jrevens]

... Plus it doesn't sound like it's powered by Cox. ... Jeff

I sure wasn't exactly taken by the sound of the first Rotax powered airplane I heard, especially being a diehard Lycoming guy, but I've come to tolerate... maybe even appreciate (gasp!) the Rotax sound. Something that immediately comes to mind is the performance by Kyle Franklin in the Speedster at OSH. While standing on the flight-line, thoroughly enjoying it, it really struck me how pleasant the sound of that little Rotax was, especially compared to the extreme noise of the typical performing aircraft during the show. I like airplane noise, but the comparison was striking, and it really was nice IMHO.

[jmodguy]

FYI the 500 hour inspection mentioned on the magnetos is not an overhaul, it is just an inspection. I can do a 500 hour inspection on a set of mags in 2-3 hours. The mechanic opens the mag up and and inspects all of the internals. Personally I don't remove the condenser or coil unless there is a good reason. If nothing is bad with the points, condenser, impulse coupling, etc. then the only parts that are replaced are a cotter pin and the woodruff key (which holds on the drive gear or impulse coupling). This inspection can get expensive if there are problems with the impulse couplings, bearings or rotor; or corrosion/pitting of parts. Sometimes the points/condenser need to be replaced, but that isn't too expensive.

And yes, these engines are very easy to work on.

My bad... yes it's an inspection - not overhaul :o