Michael Gannaway

Michael Gannaway

Member
Has anyone ever done this to create their own 344 ci engine? With the 135mm bore and 98mm stroke it would be a screamer up top. Thoughts?
 
Welcome to VAF!

Michael, welcome to VAF:D

Your idea may not work, due to piston availability issues------also bore size to crankcase hole size may come into play???

Dont really know if it is possible, just thinking of the possible pitfalls.

As to the high RPM potential, dont forget to consider the prop realities involved.

Anyway, good mental exercise:D

Good to have you aboard.
 
Mike S said:
Michael, welcome to VAF:D

Your idea may not work, due to piston availability issues------also bore size to crankcase hole size may come into play???

Dont really know if it is possible, just thinking of the possible pitfalls.

As to the high RPM potential, dont forget to consider the prop realities involved.

Anyway, good mental exercise:D

Good to have you aboard.
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From all the searching ive done the io-390 is just a 360 case using io-580 cylinders. The only real difference in the 320/360 is the crank stroke and rod length.

As far as the prop goes. Guys turn o-200s to 4000+ rpm and they find props somewhere. So why wouldnt you be able to find a prop ?
 
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Michael Gannaway said:
As far as the prop goes. Guys turn o-200s to 4000+ rpm and they find props somewhere. So why wouldnt you be able to find a prop ?
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A metal prop would be the biggest potential problem, since you'd be dealing with completely unknown harmonics... which have been known to crack blades in flight. A wood or composite prop wouldn't have any such issues, and since you're starting off with an O-320 as the base engine, the new Sensenich composite ground adjustable prop might be a choice too.
 
Michael Gannaway said:
As far as the prop goes. Guys turn o-200s to 4000+ rpm and they find props somewhere. So why wouldnt you be able to find a prop ?
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I did not say you would not be able to find a prop, just said not to forget the realities of the prop.

The prop must absorb a certain amount of HP. And it must keep the tip linear velocity under control.

Your proposed parts combination should be capable of overspeeding a prop designed for a 320, and the prop designed for a 4000 RPM O-200 will most likely not absorb the HP your engine should create.

All a balancing act.........................
 
The F-1 guys turning their props to 4000 RPM is a need for horsepower, not because they work well. Yes, the 4000 RPM O-200 makes 150+ HP, but the 2700 RPM 150 HP Lyc would provide a bunch more practical thrust.
 
Although the 320 and 360 jugs have the same bore, they are different length. So, you would need way taller pistons or longer rods. Don't know if either of those would work, or are available. Nice thought though.
 
aerhed said:
Although the 320 and 360 jugs have the same bore, they are different length. So, you would need way taller pistons or longer rods. Don't know if either of those would work, or are available. Nice thought though.
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well if you used a 360 case and eci 4.5" stroke crank with 580 cylinders. you would just need to use the same rods as the eci 370, but with a larger bore piston having the right compression height from the piston face to the wrist pin. I am sure there is a company that could produce a set of pistons for it if none are available currently.
 
Mike S said:
I did not say you would not be able to find a prop, just said not to forget the realities of the prop.

The prop must absorb a certain amount of HP. And it must keep the tip linear velocity under control.

Your proposed parts combination should be capable of overspeeding a prop designed for a 320, and the prop designed for a 4000 RPM O-200 will most likely not absorb the HP your engine should create.

All a balancing act.........................
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Toobuilder said:
The F-1 guys turning their props to 4000 RPM is a need for horsepower, not because they work well. Yes, the 4000 RPM O-200 makes 150+ HP, but the 2700 RPM 150 HP Lyc would provide a bunch more practical thrust.
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I was never saying that it made more thrust just stating that if there are props out there for that type of combination then I would assume something could be found for a 3100-3200 rpm lycoming io-400 if you managed to get the right parts to build the engine.
 
Yes, BUT...

You are quickly going to run into critical tip speeds for faster aircraft. Not such a big deal on a C185, but an RV at high speed cruise may be a problem.

Quick story found on the Web: guy is cruising along at altitude in his Glassair 3 on the way to a meeting. Decides he's going to be late, so he cranks the prop up from 2400 to 2700RPM...

...and losses 15 knots.

Since tip speed is a function of cruise speed of the aircraft as well as RPM, the tips went transonic and the thrust fell off big time.
 
Toobuilder said:
Yes, BUT...

You are quickly going to run into critical tip speeds for faster aircraft. Not such a big deal on a C185, but an RV at high speed cruise may be a problem.

Quick story found on the Web: guy is cruising along at altitude in his Glassair 3 on the way to a meeting. Decides he's going to be late, so he cranks the prop up from 2400 to 2700RPM...

...and losses 15 knots.

Since tip speed is a function of cruise speed of the aircraft as well as RPM, the tips went transonic and the thrust fell off big time.
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I would want this engine in a midget mustang not an rv but the same still applies. If tip speed becomes and issue thats when you run a shorter prop with more pitch correct?
 
Michael Gannaway said:
I would want this engine in a midget mustang not an rv but the same still applies. If tip speed becomes and issue thats when you run a shorter prop with more pitch correct?
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Yes, BUT low speed thrust falls off. Like most thing in aviation, it is a balancing act. The short stroke, high RPM engine may get killed in overall performance by a lower HP engine simply because the high speed prop is wasting much of the "extra" HP on heat and noise.

For highly specialized situations the undersized props can generate efficiencies in cruise, but for the real world, that is usually a different story. Looking at the takeoff and climb performance of the F1 racers is an example.
 
Angle valve cylinders will work on an O-320. Its been done successfully. For custom pistons call these guys:http://www.combustech.com/Products/Lycoming Pistons.html If you wanted to run at a higher RPM you can shorten the prop and increase the pitch. Simple math to determine the tip speeds. Paul Lipps designed a prop for a V8 conversion without a gearbox and as I recall it ran somewhere around 7000 RPM at takeoff.
 
rocketbob said:
Angle valve cylinders will work on an O-320. Its been done successfully. For custom pistons call these guys:http://www.combustech.com/Products/Lycoming Pistons.html If you wanted to run at a higher RPM you can shorten the prop and increase the pitch. Simple math to determine the tip speeds. Paul Lipps designed a prop for a V8 conversion without a gearbox and as I recall it ran somewhere around 7000 RPM at takeoff.
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Awesome thanks. I actually think id rather use a 360 case, io370 eci crank and rods, custom pistons for 10:1 comp using the io580 135mm bore. Making it a 400 ci engine. With HP likely around 240-250.

And to respond to all the previous comments about not knowing what will happen because it hasn't been done. Isn't that what experimentals are all about?
 
Any time you run the hp up the prop will take a beating. A friend of mine has an IO-360 in his RV8A with an MT prop, 10:1 pistons, dual Lightspeeds, 230hp. Every couple of hundred hours his MT 3 blade has to get overhauled. The shank bearings and races don't hold up well.
 
rocketbob said:
Any time you run the hp up the prop will take a beating. A friend of mine has an IO-360 in his RV8A with an MT prop, 10:1 pistons, dual Lightspeeds, 230hp. Every couple of hundred hours his MT 3 blade has to get overhauled. The shank bearings and races don't hold up well.
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You have to pay to play. I never said dreams were cheap
 
Michael Gannaway said:
...And to respond to all the previous comments about not knowing what will happen because it hasn't been done. Isn't that what experimentals are all about?
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For many of us, yes.

...But you still have to obey the laws of physics, and success rarely follows the "let's throw it against the wall and see what sticks" approach.

There are a LOT of failures in aviation. Learning from the past is and then taking an enlightened, measured approach is the best path for future success.
 
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Toobuilder said:
For many of us, yes.

...But you still have to obey the laws of physics, and success rarely follows the "let's throw it against the wall and see what sticks" approach.

There are a LOT of failures in aviation. Learning from the past is and then taking an enlightened, measured approach is the best path for future success.
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Well the io-390 works well with the larger 5.319 bore and smaller 4.375 stroke and the io-370 works well with the smaller bore 5.125 and a larger 4.5 stroke. Why cant you have both? You end up with a 400 ci 4 cylinder that will make great power down low and up high. This isnt just a throw it at the wall and hope it sticks approach. Id say the guys who ever considered some fantasy 200 hp motorcylce engine turning 13,000 rpm are the ones who are throwing it and hoping it sticks.
 
Michael Gannaway said:
Well the io-390 works well with the larger 5.319 bore and smaller 4.375 stroke and the io-370 works well with the smaller bore 5.125 and a larger 4.5 stroke. Why cant you have both? You end up with a 400 ci 4 cylinder that will make great power down low and up high. This isnt just a throw it at the wall and hope it sticks approach. Id say the guys who ever considered some fantasy 200 hp motorcylce engine turning 13,000 rpm are the ones who are throwing it and hoping it sticks.
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Not saying it wont work at all. But there are things you need to consider like:

- A whole new TV signature

- Efficiency trades (HP vs RPM vs TAS)

- Mission objective vs cost

And just so you know, your questions are a little outside the comfort zone of this forum (especially since your airframe of choice is not an RV). I'd suggest you visit this forum, which lives for the theoretical discussions like this. You will get a lot more traction over there.
 
I think your proposed IO-400 would be too heavy for a Midget Mustang. Check with Chris Tieman at Mustang Aeronautics.
o-290 cases have been bored to make O-320s, by fitting the larger cylinder, which must be a older narrow deck cylinder. This is not uncommon with air boating. It's cheaper than buying hard to find expensive O-290 piston rings, and gains about 25 HP. So this kind of work has been done successfully.
In any event, a dead stick landing in a Midget Mustang would be a harrowing experience.
 
experimental can become 'certified' at some point!

I like to think from the Wright bros. on, every development started as an experiment, right? Wright? :)

.....usually a quick answer to some theoretical questions can be found if you exaggerate the parameters. Look at the new Hercules, or the AN-70, where they hang another couple thousand horsepower on the same wing, the same distance from the ground! The prop has to transfer a LOT of torque.

Check out the Grumman E-2C with the eight blade scimitar propeller !
http://travelforaircraft.wordpress.com/2012/10/01/e-2-alpha-alpha-write/


the truth?.....
could turn out that you will only go 150 kts, with a 7000 fpm climb! :)
 
SHIPCHIEF said:
I think your proposed IO-400 would be too heavy for a Midget Mustang. Check with Chris Tieman at Mustang Aeronautics.
o-290 cases have been bored to make O-320s, by fitting the larger cylinder, which must be a older narrow deck cylinder. This is not uncommon with air boating. It's cheaper than buying hard to find expensive O-290 piston rings, and gains about 25 HP. So this kind of work has been done successfully.
In any event, a dead stick landing in a Midget Mustang would be a harrowing experience.
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There are already io-360 and one that i know of hio-360 midget mustang. I dont think increasing the bore by .181" and the stroke by .125" would increase the weight of the engine significantly
 
Michael Gannaway said:
Exactly and when those type of people succeed, everyone else stands around wishing they had done it first. You are your own limit. Don't hold yourself back.
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Well said, just go into it with your eyes open, and gather as much info as you can from those who went before you.

Good luck, please report back as things progress.
 
Mike S said:
Well said, just go into it with your eyes open, and gather as much info as you can from those who went before you.

Good luck, please report back as things progress.
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im in the information gathering stage at this point. I am like most people, I can not afford to just go buying parts and hope they fit.
 
I may be one of the old timers here but if you go find one of the old timers older than I am that were around in the early 60's when there were a lot of 290-G's around being converted to work in T-18's, you should find some info on what has been done to these engines. I have seen a Long Ez (or was it a VariEze) that had a 320 with 470 or some other cylinder that gave him a larger engine with more HP.

If you can find someone with the OLD T-18 newsletters dating back to day one, you should find some engine answers on mods to get more power by bolting on different parts from other engines.
 
Gary is correct,
I have a T-18 which came with a pile of newsletters. Can anyone conceive of a time before forums? When newsletters were copied on mimeograph and mailed out to the members? Then passed around within a group or club to control costs?
My Thorp newsletters have name lists which are checked off as each person reads it then hands it on...
The O-290G is a lot like an O-235 solid tapped cam case. It has 2 standard main bearings at the front instead of the long single piece main bearing. O-320 E2 models with the 2 Piece front main bearings were not allowed the STC to upgrade from 150HP to 160HP with the high compression piston upgrade, although Mahlon says many experimental class engines of this type have upgraded with no problems? No hydraulic propeller control on this type.
Anyway, back to the T-18 newsletters: the O-290 shares components with the O-435 six cylinder. My T-18 has O-435 parallel valve cylinders. Installing GO-435 angle valve cylinders supposedly added power. I guess the nomenclature would be IO-290, they called it the O-290G-Wiz.
The O-320 shares bore & stroke with the 480 six which only came in the GO or SGO-480 configuration, with angle valve heads, narrow deck. So my Pile-O-Parts O-290 project waits on me to find a set of Go-480 cylinders...an O-320 crank with its stronger flange, and a pile of work to bore the cases to accept the bigger bore cylinder, and other work to marry them. It's the cheap way of doing to an O-290G what the original poster suggested for an O-320. Mine will always be a wood / composite prop type engine.
I still think an angle valve O-360 variant would be a fright in a Midget Mustang, I hear the O-320 parallel valve engine equipped ones are wild enough.
 
SHIPCHIEF said:
I still think an angle valve O-360 variant would be a fright in a Midget Mustang, I hear the O-320 parallel valve engine equipped ones are wild enough.
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Maybe thats why the one I saw with a hio-360 angle valve engine only has 18 hours on it.....wild or not. I want one. We all have our dream plane and thats mine. But they want too much money for that bird. I would rather build my own slightly different from how they built N205HP
 
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