Very general engine question for Whee.....

[fairchild]

I was reading Whee's post (on another forum) about using a cont IO-360--- which crank and which case and 2000$ main bearing set. I am
maybe thinking the same thoughts about the contenental IO-360 instead of a lycoming of some kind.
I expect you engine is all done and been running for some time now-----
How is your satisfaction level with the Cont. on the bearhawk ? Did the overhaul give you any particular headaches ? Did you find a cheaper source for bearings ?
In short---- would you do it the same again ? or would you go for a Lyc. o-360 ? or a Lyc. 540 ? (now that you can stand way back and look at the experience from far off,,,,,)
Tim

[whee]

I wish my engine was done and running! haha. There are two other Bearhawks with the Conti IO360, one is flying in South America and the other is in Canada. Glenn Patterson, got yours flying?

I still think I am going to be happy with the Conti IO360 and I don't think I'll have any more into it than someone with a Lycoming engine. I needed oversized bearings and Continental is the only source for those thus the high price. A standard set of bearings is reasonable, ~$800 if I remember correctly. Nothing I've encountered so far would cause me to change my mind.

You have a long time before you need to think about an engine though. That is something you don't have to decide on till you cut the check to purchase whatever engine.

[fairchild]

Thank you for your reply !
I am surprised there are as little as two others with the cont. ( i wonder why--- your choice seemed completely straightforward to me..... )
I guess builders want to keep certain things in alignment with the designers pre-planned engine mounting scheme-- thats all i can think of....)

I looked on barnst@rmers as a test--- and I see there are quite a few more Lycoming 360's than conti 360's. I expected the reverse.

I am only thinking about it in the context of trying to decide between 2 place and 4 place---- because it appears that the 4 place would be
in its happy place with a Lyc. 540. My cousin had a conti O-300 in his 56 172 and it WAS an extremely smooth running thing. Much less airframe
vibration than a Lycoming.

I guess It would save 1000$ if one could find a conti. with a crank that didnt need grinding. But I dont see how you'd ever know that until NDT time came.

I wonder how many 4 place planes have flown using a 180 hp lycoming ? The stories I have read so far sound like you dont get all the "goodness" of
performance that you would have with the 540. Seems to me if you are going to the trouble to build from scratch--- part of the satisfaction of that
is to be able to do what the big factories dont.... (or wont)- and... have it the way you want it. (instead of henry ford's black)

Tim

[Glenn Patterson]

Hi. I have been away from the forum for a quite while. We are waiting for our final inspection that should be completed soon. The Continental IO-360 is a solid engine and is respected in our area. Our BH has a Continental IO-360G that was a front engine off a Cessna 337. We bought the engine from a 337 owner that wanted to install Corvette based engines. The engine had 800 hours,is in excellent condition and has full compression. The Cessna 337 series engines are often used for power up grade STC's. The prop is an 82" McCauley C203 constant speed that is a very common prop as they are used on 170s with STC's,172's, 180, 182 & 185 & Stinson STC. The 82" blade tips at full rpm operate run just below Mach1 and an efficient. There are a lot of 82" props on IO-360's so a comfortable decision.The prop hub is the same for the C203 with the blades simply trimmed to the application. We bought a first run prop & had it rebuilt for half the price of a new prop. Q1 Aviation did the overhaul and said the prop required less work than anticipated so they came in well under their quote. We bought an obsolete Cessna 337 rear engine bed mount for $100 and reworked it for our BH. Bob Barrows assisted with the tube sizes for the mount. We needed a spinner assembly and picked one up from a local company for $200 which was a deal. The original exhaust was not going to work with our set up. We had Aircraft Exhaust build a pair of 3 into one header exhausts that left a good wide open lane for cooling air to exit the cowl. I read a lot on cooling & tried to use some of the principles of the pressure cowls & racing cowls. We used the old baffles to make patterns to build tight fitting baffles to the engine with rubber to seal it to the upper cowl and the nosebowl. The upper engine cavity is sealed to keep the air pressure over the engine. We used an MC3A bowl that was modified a fair bit to fit the engine. The air inlets were narrowed about an inch to cover the fuel pump & fuel lines. The lower half shape was mocked up with the MC3 bowl then a mold made to make a new lower half with fiberglass. The air inlets are ducted to project the air up into the upper engine cavity. The exit opening on the fire wall has the half bulb shape on the corners to reduce the turbulence of the exit air. The cowl has a good taper under the engine from the front to the firewall that may also help allow the air to flow fairly uniform through the engine. We took great care to keep the space open under the engine and have a direct path to the exit. We have run the engine on the ground a quite a bit. The cylinders are all within a few degrees of one another and stay cool so hopefully the cooling has worked out.

The Continental IO-360's provide the full 210hp as advertised and are miserly with the fuel. A couple pilots with Bushmasters say they have lots of power and easy on the fuel. We went with the engine because it was local, decent power, good remaining life and bought at a fair price. We installed the header tank the similar to certified aircraft that simplifies the fuel system. We have friend that is an airline pilot that owns a Bushmaster powered by a Continental IO-360 with the 82" prop. He really enjoys his airplane and loves the engine. The engine starts quick and runs extremely smooth. The Bushmaster had a small return tank mounted on the firewall that was a nice arrangement. The cowl has a line without the air box.

A lot of time was spent shaping the nose bowl otherwise the installation is fairly reasonable. I think if a person wants a Continental IO-360 then investigate the engine thoroughly &go for it.

Hear are a few photos of our build. I could not find a good side shot of the engine

[whee]

The plane looks great Glenn! It's comforting that our engine mounts look basically identical. Either both our engines will fall off or not😆 Though I'm considering modifying mine so the factory Hawk XP exhaust fits without modification.

I can't wait to hear about your first flight. I'll be slinging a longer version of the same prop so it will be interesting to compare notes after I'm flying.

[Glenn Patterson]

Whee. Thank you. Credit for the paint scheme goes to George Maddux's patrol. The emerald green & off white with a very fine metallic was the only colours that we all could agree on. George's airplane was a great example of green paint on an airplane.

We lucked out on the engine mount. Barrows spec'd some heavy tubing for attaching the bed mount to the attach points. My welder partner was upset with the weight of a couple of them so I think our engine mounts will stand the test of time. Reworking the Cessna 337 rear mount certainly made the installation easy. An aircraft engine overhaul shop in Winnipeg gave us an empty cracked block that was perfect for the mock up work. The spinner flange almost got us with the nose bowl. I did the plywood disc support for the nosebowl & thought I was good on setback. Some tense moments fitting the cowl on after mounting the prop & the nosebowl cleared the back of the spinner by a 1/4". I wanted to seal around the prop hole on the engine side but did not manage it so the close fit is good. I read while researching pressure cowls to learn that a bad fit around the prop hole can lose up to 20% of the cooling air through the propeller hole. I think that if your exhaust goes right & left to leave a good clear run under the engine that you should have no issues with cooling. We added the aluminum half bulb or half tear drop radius on the firewall cooling exit. I read on one of the aircraft racer sites that this makes the exit air flow more laminar to assist the airflow. The sharp corners on the outlet creates turbulence that hinders air flow.

I don't know what the XP exhaust costs. We went with Aircraft Exhaust and that owner has taken back his original company Experimental Exhaust. http://www.experimentalexhaust.com/
The owner Chris was great to work with and the work is first rate. My partner is a red seal welder and was impressed with the craftsmanship. They sent us the mock up parts and we routed the exhausts trying to keep all the runners about equal in length. We made an error on the cuff outlets as the heat duct crossed in front of the cowl cooling exit. We windowed the piece with the outlet with an offset the spun it 180 and TIG welded the piece back in. The exhaust was competitive & I can tell you what it was with a PM if that helps. The mock up parts are purchased & when the mock up is returned then the mock cost is fully credited to the completed exhaust. We had the skills to put an exhaust together but life is only so long and the airplane needs to get done. I also went out west as a part time hired gun for a three years so I paid for the exhaust in lieu of my absence. The header exhaust improves engine exhaust flow that could to give a percent or three improvement on hp. If it is 4 or 5hp then that is a plus.

We had planned to go to an electronic ignition that gives about 5-6% hp gains by the computer controlled variable timing plus the fuel savings. Between the exhaust and the electronic ignition that would put the engine around 225hp which is not bad. IO470 territory for power w/o the weight. Budget got in the way on the electronic ignition plus the delay on E-Mags 6 cylinder electronic ignition roll out. We had our name on the list but let it go.

I did a lot of modifications on the MC3A nose bowl & can give some detail if you are not there. I set the bowl in place and developed a template for the lower half. I then reshaped the bottom half of the purchased bowl with body putty and templating the left to right to stay symmetrical. Once I was happy with that then I waxed it the piece and then fiberglassed it to make a female mold, Added cushion foam for void stiffeners to the fiberglass mold and glassed those over to create a good stiff female. I then made a new fiberglass bottom with the mold. The top flange needed to go up about 1/2 an inch or so. I run a jig saw across the upper half and relocated the top with aluminum strips and clecoes. I glassed in the missing strip and it worked out well. I did not like the shape across the top so I sliced it in several places. The top shape was held with a plywood template backer then the cuts repaired to give me the new shape. I sanded it down on the inside and put a thin layer of glass on to restore its original thickness. Put the old fiberglass and body work skills to work. The white showing on the final assembly is the untouched areas. I enjoyed the creative process.

We weighed in on going with an 84 in. A lifetime of pump and fan laws got in the way. The PPonk tip speed calculator showed that at max rpm the 82 was just squeaking under the Mach1 tip speed for best efficiency. There was not enough knowledge in the team to know if going over Mach would put any bad harmonics into the engine. We are 2 hours between communities here that are in a line along the TransCanada hwy and the rest is thousands of square miles of empty bush or water with no walking home. We leaned to the max length on the known & proven side of the equation. I spoke to one AME had done many STC conversions and he upgraded his personal Cessna to the IO-360 power plant with an 86" prop. He said it was a scream but his neighbours hated it. It will be fun to see how yours works out.

[Glenn Patterson]

I sent you PM on the details and cost for our exhaust. The fabricated exhaust is competitive to purchasing a certified exhaust. It may even be less. We are happy with the quality of the exhaust system that we purchased. The fabricated exhaust allowed the wide open space under the engine for the cooling air to exit efficiently without any interferences. That is one good bonus of the COntinental IO360 is that the fuel system and air induction is on top of the engine out of the way. I think it makes for a lot cleaner cooling air flow.