Can an aircraft engine be inverted or must you use special engines?

Not quite sure what you're looking for.  The usual reason for inverting an engine is to put the thrust line in a different place.  This sort of thing can really make a difference with a straight-4 or straight-6 engine (like a Ranger) but a conventional horizontally-opposed aircraft engine is quite a bit less deep.  Mounting it inverted just doesn't buy much.

I don't think you'd be able to flip a run-of-the-mill Lycoming or Continental.  You'd probably want something with fuel injection (vs. a carburetor), and the oil tank would be on top.  Companies make aerobatic versions of stock engines (such as the AIO-360) and you might have better luck with one of those.

If you're looking for a new-production version of an inline four, the Walter Mikron (aka LOM) is the only thing that comes to mind.  I hear differing opinions as to whether they are really available or not....

You'll probably need to go for an aerobatic version of whatever version you're talking about. A regular engine that's inverted will need a special type of oil system because gravity will be causing the oil to go somewhere other than where it need to be.

Even inlines and v powered fighters that had inverted engines required some mods to keep the oil (and actually fuel for that matter) flowing correctly (reversed oil rings, etc)

A few engines (Lyc O-540 & Franklin O-330) started out in airplanes and later adapted by helicopter companies to be mounted pointed straight up. Thats "half inverted." A little tinkering was needed with the oil scavenging and induction so that the carb stayed upright.

If you were used to the RPM limit in a Stinson or Comanche, you would be shocked to see the same engine at 3100 - 3200 in a Bell or Hiller.

Bob

As mentioned by others, Lycoming makes aerobatic engines that are made to run inverted, at least for a time. The AEIO-360 engine is a currently-made popular model. I don't think it would work well to run it inverted all of the time, however.  A better choice might be the older AIO-360 which is a dry sump engine. It needs a remote oil tank, but saves you the problem of figuring out how to put oil in an upside down engine. 

There are old Ranger engines available that are designed to be run with the cylinders pointing down (inverted). LOM also makes new inverted engines that some homebuilders have used with modest success.

err..... why?

 http://www.deltahawkengines.com/

The delta Hawk engine can be had in an "A" or "V" form to accommodate crank placement.

Other than 2 cycle ..... and I will say air-cooled (i.e. chain saw) running inverted as produced will cause a very quick and violent end to the engine.

All of the oil control, drain back from heads, cylinder wash from rod and crankshaft spray is planned for and dependent on gravity to return it to the oil pump. Cooling systems have high points manufactured to "burp" air out. Block failure would be a give to run a skidoo / seadoo type engine inverted due to air build up. (even with the 40-50 psi in block)

Nothing is impossible,,,,, Cost Prohibitive........

How many of each type are currently flying?

What i mean is an inline 6 or 4 cylinder engine that is permanently inverted and mounted that way in an aircraft.

NO!... Belt "Redrives" have been very sucessful in relocating Prop placement. Many airboats run bigblock V8's. Power is not your issue. Gravity for the $ saved. [early bi-planes did fly on model A and T 30hp flattie's]  Iron blocks and heads with water, radiator, etc. are too heavy by comparison to aluminum 4 cylinder / V-6 with a belt under drive to keep the prop tip speed sub-sonic. Guessing that you would have to hire this done, expiremental, very few make e-lsa, Cost Prohibative.

VW / Corvair remanufacture for A/C $7-10K , Very good used A/C starts in that area.

Again this is just what I have leared about planes..... Auto's I have been a master mech.

Daniel, Tom said it well.  Another thing not mentioned is a thing called hydro static lock. Thats when, on shut down, un scavenged oil drains from the crank case, down the cylinder bore, past the rings and collects in the combustion chamber. This happens in radial engines. You have to pull the prop through and if it hits a solid slug of oil, you need to remove a plug and drain it out. This would be irritating if you had 4, 6 or more plugs to pull on an inverted engine. I have no experience with Rangers,or Gypsies so I don't know if they have this problem. I would have to think that a homebuilt engine could be more likely. I could be just imagining a problem that may not exist.

Bob

Hi,

How many aircraft are currently flying with DeltaHawk engines? One is flying (Velocity with upright engine in pusher configuration), and two are nearing flight test (a Cirrus SR20 with inverted engine in tractor configuration and a helicopter with a vertical model).  A commercial customer has flown another upright pusher in a Velocity.

Why aren’t there more DeltaHawk powered aircraft flying publicly? We’re waiting for production level engines before expanding the flight program.  We’re working with partners to develop installation packages in anticipation of having tested production engines available at the beginning of this year.

Thank you for your interest in DeltaHawk engines. If you have further questions, please let me know.

Sincerely,

Rip Edmundson

DeltaHawk Engines, Inc.

Racine, Wisconsin USA

http://www.youtube.com/watch?v=n_hyZBYiSvw&p=9F2CBA8F31113EBA&playnext=1&index=19 

"

First flight of a DeltaHawk engine (the company Velocity) was over seven years ago.  According to a 2005 release on their web page, "The first pre-production engines rolled off the line at Kurt Manufacturing in Minneapolis in August and are being sent to OEM customers for testing in their new products."

That's August of 2005.  Since then, only one other airplane has flown.  None have yet flown in the inverted configuration, despite installation in a Cessna test bed that, curiously, was not mentioned in the above response.

http://www.deltahawkengines.com/DH160A4%20Running.shtml 

The company should be applauded for their tenacity...certifying a new aircraft engine is not a simple process.  The fact that they've stayed in business for over ten years without a product on the market is a testimony that they've got the solid financial backing that is necessary for an endeavor like this.  The product is a needed one...there are lots of countries that need GA aircraft that can run on Jet-A.

However:  With a dearth of flying examples, I wouldn't really recommend them to the average homebuilder quite yet.  It's nice that the company has an inverted configuration like the OP wants, but the fact is, it hasn't even flown yet.

That is a very interesting engine.   All kind of possibilities.  How much fun would it be to taxi your RV or what ever over to the Jet A pump,  or tell the fuel man to take the 100 back and get the Jet A truck.

The detail not shown in the video is the cylinder heads screw in and out for other fuels. Huge need for the forign market. Multi-fuel for military really has a draw for all.

Resleaves for rebuilds will be far less expence, Rod / main brg... supercharger and oil pump.... Major overhaul, Done.

How long is the build going to take? What power is desired? more than 100hp if we are talking 6cyl. Just information the OP, and many may not be aware.

LOM Praha still produces their LOM inverted 4 and 6 cylinder engines just outside of Prague C. R. They are not actively marketing them in the west, but can supply anything one needs from any parts to a complete engine.

I have been running the LOM M332A 140 hp., inverted 4 cylinder for the last three years and have enjoyed it.  It will not produce the thrust of an O-320, but is very economical (7 gph) and smooth. It has been bullet proof and I have not needed any parts from the factory so cannot speak from personal experience, but have heard good things from the other guys running them.

Luke

I had the pleasure of owning a Zlin 526F for a couple of years, it had the 6-cylinder inline inverted 180 hp LOM 137A engine.  It was one of the smoothest-running and reliable engines I had ever flown.  Also sounded very cool, I am told, although I never heard it from the ground!! 

If you can get one I would highly recommend it, did lots of aerobatics with it.  The oil reservoir was in the left wing root, the only thing you had to watch was that somebody didn't mistake it for the fuel tank and fill it with avgas.

        Cheers, Tony

Steve Whitman of "Tailwind" fame  sold plans for converting an aluminum V-8 (Oldsmobile) for inverted use in his Twailwind.

Chris Beachner also sold plans for converting an aluminum V-8 (Buick), These were of the 1964 era and later, as the same Buick engine was later used in the LandRover.

I believe the Moony-Mite used the 4-cylinder Crosley engine inverted. That same engine was used by Homelite, on end, as an outboard (boat) engine. The Crosley auto had it in the normal head-up position.

I once owned a Fairchild 24-R with the inverted Ranger, and never had any problems with that.

EAA should have information on Whitman and Beachner conversions. Perhaps Aircraft Spruce has them in addition to the Tailwind plans they sell.

Hope this helps.    Tom Carpenter