That 235hp was with stock pistons which should be able to run mogas fine. He did say he recommended against mogas and with 100ll could turn up the compression and get even more power. They have dyno proof of that 235hp from a IO360.

I need to clarify; they never said the IO360 would run on mogas just that the 8.5:1 compression ratio was mogas compatible.

whee wrote:So after talking to Lycon it just makes sense to stick with my IO360 plan. They can build me a 235hp IO360 that weighs ~350-360lbs that will swing a 86" Mac and still be a certified engine/prop combo. I don't really care about the certified part but it does make the phase 1 test period 25hrs instead of 40. He also said it doesn't cost any more to overhaul a 360 than it does a 470 or 520.

That sounds like a great plan. Does the BH have better CG envelope / elevator authority with more weight out front?

Either way, better power:weight and 2 less cylinders to maintain sounds like the way to go!

I'm also looking at building a "forever" plane in a few years and am looking forward to your build.

I fly a Maule behind the TCM IO360 and find it to be very well balanced. I like the "feel" of it more than the larger engined Lycoming 540 Maules. I have always wondered why I don't hear about more Bearhawks with the IO360. It has a great power to weight ratio. I have also heard of guys regularly running mogas on experimental TCM IO360s with compressions as high as 11 to 1.

Chet

TradeCraft wrote:

whee wrote:So after talking to Lycon it just makes sense to stick with my IO360 plan. They can build me a 235hp IO360 that weighs ~350-360lbs that will swing a 86" Mac and still be a certified engine/prop combo. I don't really care about the certified part but it does make the phase 1 test period 25hrs instead of 40. He also said it doesn't cost any more to overhaul a 360 than it does a 470 or 520.

That sounds like a great plan. Does the BH have better CG envelope / elevator authority with more weight out front?

Either way, better power:weight and 2 less cylinders to maintain sounds like the way to go!

I'm also looking at building a "forever" plane in a few years and am looking forward to your build.

The TCM IO360 still has 6 cylinders I'm pretty sure...
But I like your plan Whee. Sounds well thought out and makes a lot of sense.

Much like a Maule the Bearhawk gets aft CG easily with the Lyc O360. With more weight up front you have more usable CG for putting stuff in the baggage and the elevator is powerful enough to compensate for the forward CG when empty.

The TCM IO360 is a six cylinder engine so it is heavier than a Lyc O360. I think the extra weight will be the right balance between not enough too much.

whee wrote:Much like a Maule the Bearhawk gets aft CG easily with the Lyc O360. With more weight up front you have more usable CG for putting stuff in the baggage and the elevator is powerful enough to compensate for the forward CG when empty.

The TCM IO360 is a six cylinder engine so it is heavier than a Lyc O360. I think the extra weight will be the right balance between not enough too much.

Random question... What's the weight difference between the TCM motor and a lyc with equivalent hp?

I don't have the engine manuals for the Lycoming engines so I don't know what "dry weight" means but the IO390 (210hp) weight is ~308lbs and the O540 (235-260hp) is ~400lbs, actual weights for the "O" are 387-415. As with all engines their weight varies with specific model so there are lighter and heavier 540 engines but I've been told to just plan on 400lbs.

Weight info for the TCM IO360:

whee wrote:I don't have the engine manuals for the Lycoming engines so I don't know what "dry weight" means but the IO390 (210hp) weight is ~308lbs

The Lycoming O-360 making 200hp tends to run around 310-320lbs, for 180hp it's 285-300lbs, but it varies with the engine block model.

Those are "dry weights". I understand dry weight to including carburettor, mags, ignition harness, engine baffles, spark plugs, tach drive, starter, and alternator.

http://www.lycoming.com/Lycoming/PRODUCTS/Engines/Certified/360Series/EngineData.aspx

Whee if you have a chance go and buy one of those digital load cells/scales for $199.00 That will be the most used device in your home build program. I bought one at the start of our Bearhawk build and I still use it all the time on my Cessna 175 project. We needed to know what the real weight of a running O-540 with all the stuff attached really weighed when you just undid the motor mount bolts from the firewall and moved it forward. We needed to know this weight and the CG from the firewall so that we could match those numbers with the Land Rover V8 package. I was lucky enough to have access to Langley Aero Structures and he does lots of motor removals etc. and as the motors came off we would weigh them. I was only focused on the big six cylinder motors so I did not weigh and of the 4 cylinder motors or the small six's. What I found was the O-540 with a two blade prop was the lightest at 560lbs and the CG 20" ahead of the fire wall. The next lightest was the TCM IO-550 then the IO_520 and the heaviest was the O-470 at 612 lbs. We did a lot weighing and designing to match the 540 numbers. We came within 5lbs and the CG was right at 20".
My current project is a Cessna 175 with a chevy LS3 v8 conversion and my goal is to match or better the O-470 numbers as that is a common conversion to that plane and it seems to work.
What I am saying is do not believe any of the factory numbers because it gets real confusing and that is done on purpose. I swear that some of those motors must have helium poured in the blocks. Go get one of those scales and find out where you can weigh one of the running motors you want to use. I think that TCM IO-360 might make a real good package for the Bearhawk.

175 magnum wrote: What I am saying is do not believe any of the factory numbers

Really??? I was with you until that statement.

It's a great idea to weigh the engines as they come of aircraft. That would tell you a lot about complete installs. But for comparing lots and lots of different engines, it's not terribly practical.

I think I would trust the numbers used by the factory to certify the engine. I would like to think they are checked and controlled to meet those weights within a certain tolerance.

I bet if you added up all the weights of the things installed, you'd get within a few percent of the actual measured weight, using a calibrated scale.

For instance, 560lbs for an -540 with all the trimmings, oil, and a prop. That sounds right.

What I found was that so often when a weight was given it also stated: does not include starter/exhaust etc.etc. or some variation on that theme. The weights that were being quoted were going to make it almost impossible to match using an auto engine. I decided that I needed to find out what a real life running aircraft engine weighed and once I started actually weighing engines I quickly realized that we could match those weight numbers.
Because I was getting so many different answers this was my way of getting everything on a common playing field.
When the props, spinners, baffles and motor mounts were removed and the oil drained the motors always weighed more that the weights I was given.
All I am saying is really do your home work on these motor weights and confirm exactly what is included because you might not be saving as much weight as you thought you were.

I'm reviving this thread because of some info in the IO470 vs Pponk thread Halestorm started. The Norland STC removes the injection system from a IO470 and let's you put a carb on it and put it back on your 182 using the same engine mount you have before. Previously I was told the IO wouldn't fit on the same mount as the O470. Avipro makes a mount for the O470R which I thought wouldn't work for the IO but now I'm thinking it will.

Also, I've seen some really good deals on IO470 engines and only one ok deal on a IO360.

Do the IO and O 470 use the same cylinders, i.e. do the O470 cylinders have the fuel injection nozzle port but plugged with a removable plug?

whee wrote:Do the IO and O 470 use the same cylinders, i.e. do the O470 cylinders have the fuel injection nozzle port but plugged with a removable plug?

http://www.superiorairparts.com/millennium-cylinders/application/
Here is a superior application chart.

Yes some are the same.
The hole is used for prime on an O-470.
There are different cranks for some models. Not sure exactly what is different though other than some do have different balance weights.

You can install the induction opposite on a continental. Being an experimental mounting/fabricating the induction throttle body mount between cylinders 1 and 2 is doable. Might be a OEM manifold that'll work. I need to weigh my prop...my IO520 weighs 462 pounds loaded...less the baffles. What's a three blade square tip McCauley from a 207 weigh? Also on the CG issue. Originally Bob Barrows set the prop flange 58-1/2" ahead of the datum line. Then changed to 56-1/2". Folks were installing heavy interiors....creating aft CG problems. Bob changed the prop flange to datum back to 58-1/2" Now I'm thinking I'll have an aft CG problem....the O-540 weighing in at 560+ I know my prop doesn't weigh 100 pounds. My cowl weighs 18 pounds... 54-1/4" ahead of the datum line.....my engine is to far aft..... And.....my counterweight arrangement prop combination can be operated continuous at any RPM under 2700. Bob ran his O-540 at 1900 RPM. I'm hoping the Gami injectors, lean of peak at 1900 rpm will be more fuel miserly.

whee wrote:Carb ice isn't a concern for me, I know how to pull the carb heat knob. I'm not set on FI but I do want mogas and <10GHP. A IO470K is 225hp, reasonable weight, approved for mogas, and at LOP will burn 9.5gph at 60%power. Sounds pretty good to me.

Like I said earlier, I'm burning about 11 gph at 21"/2300 (about 62% per the power chart) in my 180, and it's good for around 140 IAS (probably about 135 mph groundspeed) down low. I lean very conservatively, I could probably knock off another 1/2 gph by getting more aggressive with the red knob. Considering how many O-470's are available vs IO's, I think I'd just stick with a carburated version and just accept the extra 1 gph burn as the cost of keeping it simple. I think there's probably fair to say that there's a lot more O-470's available used than IO's. And no frankensteining required.

I'm not scared of Frankenstein either

Need to let some of this info soak in a little.

Trouble with frankensteining is that unless you're very knowledgable, you might unwittingly end up mis-matching some engine components together. Or not knowing whether a certain prop will be compatible with your mongrel engine.

m_moyle wrote:... Now I'm thinking I'll have an aft CG problem....the O-540 weighing in at 560+ I know my prop doesn't weigh 100 pounds. My cowl weighs 18 pounds... 54-1/4" ahead of the datum line.....my engine is to far aft..... And.....my counterweight arrangement prop combination can be operated continuous at any RPM under 2700. Bob ran his O-540 at 1900 RPM. I'm hoping the Gami injectors, lean of peak at 1900 rpm will be more fuel miserly.

That sounds too heavy for an O-540. Around 400# per Lycoming website:
http://www.lycoming.com/Lycoming/PRODUC ... eData.aspx

TIO-540 will be near that weight.

marcusofcotton wrote:

m_moyle wrote:... Now I'm thinking I'll have an aft CG problem....the O-540 weighing in at 560+ I know my prop doesn't weigh 100 pounds. My cowl weighs 18 pounds... 54-1/4" ahead of the datum line.....my engine is to far aft..... And.....my counterweight arrangement prop combination can be operated continuous at any RPM under 2700. Bob ran his O-540 at 1900 RPM. I'm hoping the Gami injectors, lean of peak at 1900 rpm will be more fuel miserly.

That sounds too heavy for an O-540. Around 400# per Lycoming website:
http://www.lycoming.com/Lycoming/PRODUC ... eData.aspx

TIO-540 will be near that weight.

He is talking about total weight ready to run, prop and all, not dry weight.