What new engine?

[spinner2]

If you were going to choose an engine for an experimental Cub project today, what would you go with? This would be a big Cub with 1000 pounds+ useful load. And probably a constant speed prop. I'm thinking a minimum of an O-360. And probably compression in the 8.0/8.5:1 area so that car gas can be used. And electronic ignition.

Titan seems to have the best information on their offerings online. I see their X-360 180 hp, X-370 185 hp or 195 hp at high compression.

Lycoming Thunderbolt: O-360 and O-390

Superior: XP-360 180-185 hp

And there are custom builders like Ly-Con and Aero Sport with an O-375.

What would you guys go with and why? Thanks.

[DENNY]

When I called Titan almost a year ago they would only make a 0340 or 0370. I wanted a 0360 to assemble it myself so went to Superior. I like there sump design but had to find a crankshaft as they had none. Since the time of order they also had issues with roller lifters and problems supplying cylinders. All the big parts are ready to ship just waiting on a few small ones. I heard Lycoming is also having problems with parts supply chain and price increase in a month or so. I am doing Bendix mags due to my travel plans and the repetitive high CHT issues with electronic ignition. I would fly behind any of the three, just get your order in early because it could be a long time getting one. Looking for a set of DLC lifters for a 0360 if some one knows of a set let me know.
DENNY

[stewartb]

Thunderbolt IO-390 with Whirl Wind 200A and SAP cold air induction. Best suited with an extended airframe. I wouldn't be happy with anything smaller on my plane. If I was using a standard length airframe I'd stay with a parallel valve 360 and a fixed pitch.

Base model compression for the 390 is 8.9-1, so not a good candidate for mogas. With that in mind, I went 10-1. No regrets except when trying to do a compression test by myself.

[Colorado-Cub]

I have been waiting on a Titan 340 for 15 months now with no end in sight. You may want to avoid them until they get their lead times down a bit...

[phdigger123]

I ordered an O-320 from Superior in early November. They said 12 weeks. I got it in eleven.

[Colorado-Cub]

I ordered an O-320 from Superior in early November. They said 12 weeks. I got it in eleven.

If I only knew then what I know now...That is the route I should have gone long ago.

[Olibuilt]

I had interest in AC-AERO IO-409. https://www.ac-aero.com/legion-kits/





Quote from AC Aero:

''The Thunderbolt 390 is an Angle Valve engine with Dynafocal mounts. Therefore this engine will incur additional cost and work to install new motor mount, exhaust system, ~ 35 weight and balance adjustment, Fuel system to run mechanical fuel injection, and likely cowling mods as engine is wider than parallel valve engine.
Other stroker engines. Less Cubic inch, either not available, or recalled due to component failure issues.
409 engine using AC-Aero Components:

• Same foot print as the O-360 Parallel valve engine, so no additional costs associated with motor mount changes, cowling change, exhaust, etc.
• Uses Standard bore Lycoming or Lycoming clone 0-360 wide deck cylinders (or for additional costs, lightened Cylinders [- ~ 8lbs]).
• New AC-Aero counterweighted stroker crankshaft, new light weight rods, pistons, rings, wrist pins, clips, and conrod bearings. Although Pistons and conrods are lighter, the stroker crank is heavier. The combined components increase engine weight by about 19 lbs ( light weight cylinders could reduce that increase by 8lbs for a total increase of 11 lbs).
• We recommend using piston oil squirters to help transfer heat from increased horsepower into the oil to better keep CHT under control (therefore, we recommend a larger oil cooler).
• Although ASAP is fine with carbureted engines, ASAP recommends a custom intake to ensure that horsepower gains are realized.

''

[stewartb]

When you get into big displacement hot-rod engines you need to have a plan on how to keep them cool. Angle valve heads make more power and have more cooling fins. I enjoy not fighting high CHTs for the first time in my flying life. Since I had capacity for more oil temp I went to higher compression, and now my dual coolers are running full open where my old IO-400 never needed it. Planning for temperature management should be on every builder’s mind, and having a knowledge base like what’s represented here should be a useful asset. Displacement, compression, horsepower, prop, cowling, oil cooler…. Lots of nuances. This is one of the fun parts about creating an airplane.

[john schwamm]

When you get into big displacement hot-rod engines you need to have a plan on how to keep them cool. Angle valve heads make more power and have more cooling fins. I enjoy not fighting high CHTs for the first time in my flying life. Since I had capacity for more oil temp I went to higher compression, and now my dual coolers are running full open where my old IO-400 never needed it. Planning for temperature management should be on every builder’s mind, and having a knowledge base like what’s represented here should be a useful asset. Displacement, compression, horsepower, prop, cowling, oil cooler…. Lots of nuances. This is one of the fun parts about creating an airplane.

Stewart,
Wonder if there is any way to lighten up the IO-390 motor? Flew an experimental Husky with one, climbed like crazy, went fast if one did not care about fuel burn, but nose heavy.
Maybe magnesium sump if one made? lightweight flywheel? Not sure what could be done to make much lighter?
John

[JohnnyR]

As of last week's report from their sales manager, Titan will only do 340 and 370 stroker engines (no 360's).

When I called Titan almost a year ago they would only make a 0340 or 0370. I wanted a 0360 to assemble it myself so went to Superior. I like there sump design but had to find a crankshaft as they had none. Since the time of order they also had issues with roller lifters and problems supplying cylinders. All the big parts are ready to ship just waiting on a few small ones. I heard Lycoming is also having problems with parts supply chain and price increase in a month or so. I am doing Bendix mags due to my travel plans and the repetitive high CHT issues with electronic ignition. I would fly behind any of the three, just get your order in early because it could be a long time getting one. Looking for a set of DLC lifters for a 0360 if some one knows of a set let me know.
DENNY

[stewartb]

Stewart,
Wonder if there is any way to lighten up the IO-390 motor? Flew an experimental Husky with one, climbed like crazy, went fast if one did not care about fuel burn, but nose heavy.
Maybe magnesium sump if one made? lightweight flywheel? Not sure what could be done to make much lighter?
John

If you want a lighter IO390? Look at the Cubcrafters IO-393i. When money’s no object they can make it lighter. They quote 10# heavier than an o-360, but I doubt they’re including mechanical and electric fuel pumps in that claim. And they don’t mention the CS prop. With the X Cub I question what benefit does added horsepower provide when the airframe isn’t adapted to utilize the power? The same question would apply to a Husky. Is improved rate of climb worth the added weight on the nose? Obviously it is to some guys. On the flip side those guys may scoff at my Cub. To each their own.

[stewartb]

Nephew just bought a new custom SQ that has a 379. Never heard anything about this one. An IO-375 with monolithic cast aluminum cylinders like the ACE 409s. He says it rips.

[Olibuilt]

Nephew just bought a new custom SQ that has a 379. Never heard anything about this one. An IO-375 with monolithic cast aluminum cylinders like the ACE 409s. He says it rips.

And who is that engine builder?? Need some specs and info!! Please let us know.

[stewartb]

I’m traveling but will try to get details when I get home. I know you’re hip on the “new” 409 but that engine doesn’t use the aluminum cylinders that I can see. I don’t know who’s making them.

[skywagon8a]

My curiosity is up. What is this " monolithic cast aluminum cylinders"?
Then I found this: https://european-aluminium.eu/media/1575/aam-applications-power-train-3-cylinder-linings.pdf

A lot of reading, but informative.

[Olibuilt]

I’m traveling but will try to get details when I get home. I know you’re hip on the “new” 409 but that engine doesn’t use the aluminum cylinders that I can see. I don’t know who’s making them.

Yes the "new Ac-Aero 409" is very tempting. And I don't understand why we don't see it more ??



240hp @ 2700rpm for 270lbs according to Ac-Aero:

[eskimo77]

AC-Aero monolithic, liquidcooled cylinders.
https://www.ac-aero.com/gladiator/

[stewartb]

I know a few guys with monolithic aluminum cylinders and none are water cooled. Kevin Eldridge’s ACE 409s had them. AC Aero’s are different.

[1934A]

AC-Aero monolithic, liquidcooled cylinders.
https://www.ac-aero.com/gladiator/

This is the first i've heard of this engine. Looks interesting, for sure. Anyone here have any experience with them?

[eskimo77]

Apparently the air-cooled AX40 and AX50 cylinders were previously made by the same outfit, but are discontinued. And there are a couple Service Bulletins for them. Might pass the link on to your nephew Stewart.

https://www.ac-aero.com/legacy-service-bulletins/

[stewartb]

I know a few guys with ACE 409s. My nephew’s engine is more of a bastard as far as I can tell. He’s already wary of the cylinders. Experimental aviation. I will pass it on but I suspect those guys know more that me so are already familiar.

[hotrod180]

A guy I know used to have an experimental he built with a 360.
After it had been flying a few years, he decided to pull the sub-500 hour engine,
which was still running great, & have it rebuilt into a 375 stroker.
He raved about it afterwards, but IMHO it seemed like a lot of time & $$$ for a minimal improvement.

I'm curious if all these newfangled 375/390/formula 409 engines are really that much bang for the buck vs the tried & true 360?

[skywagon8a]

I'm curious if all these newfangled 375/390/formula 409 engines are really that much bang for the buck vs the tried & true 360?

One thing I've noticed is, more emphasis is placed upon souping up engines without much thought going into improved propeller blade shapes. With the modern CAD-CAM capabilities some extremely efficient propellers can be designed which could give as much improvement without extra fuel burn and high CHTs.

How about a simple controllable (not constant speed) modern highly efficient prop? Perhaps a two position prop? A prop which allows maximum rpm for take off and reduced pitch for cruise would likely produce at least as much if not more than a souped up engine alone.

[stewartb]

These big output engines and modern CS props allow us to use bigger airframes, bigger wings, higher gross, etc. I’m a fan.

[fishhook]

I ordered an O-320 from Superior in early November. They said 12 weeks. I got it in eleven.

I had called Superior back in october and november and they told me they quit making the 320 and 360 for the time being due to "crank issues". I have been hunting around for an engine for over a year now, and with Titan being 12-24 months out according to the sales guys. I would have gone with a superior 320 in a heartbeat, and it bewilders me why they would tell me no 320s, but now I find out they were available. I will be calling them again monday, maybe the person I was talking to with Superior was misinformed due to the 360 crank debacle.

[stewartb]

Just got a message from a friend. A factory 0-470 is $60K. $17K for a core. 12 months delivery time. Holy sh-t. I dream about building another plane but I probably won’t. Lucky me.

[Kahles56]

One thing I've noticed is, more emphasis is placed upon souping up engines without much thought going into improved propeller blade shapes. With the modern CAD-CAM capabilities some extremely efficient propellers can be designed which could give as much improvement without extra fuel burn and high CHTs.

How about a simple controllable (not constant speed) modern highly efficient prop? Perhaps a two position prop? A prop which allows maximum rpm for take off and reduced pitch for cruise would likely produce at least as much if not more than a souped up engine alone.

An Aeromatic hub with modern carbon fiber blades would fit the bill, now to find or build carbon fiber blades I have the hub for a a2b 320.
Another project , Dam!

[john schwamm]

Saw where Aerosport just received 6 new stroker cranks to build what they call the 0-375 motor. So short turnaround there it appears.
John

[JohnnyR]

Saw where Aerosport just received 6 new stroker cranks to build what they call the 0-375 motor. So short turnaround there it appears.
John

I put in with them for an IO375 in early Feb ‘22 and they reported then a minimum 12 mo turnaround. Who knows at this point…?
J

[john schwamm]

Just got that info from them today on 6 new stroker cranks in stock now. And got another 0-375 delivered in April, ordered late last year, so great delivery times for me.
John

[ron]

Saw where Aerosport just received 6 new stroker cranks to build what they call the 0-375 motor. So short turnaround there it appears.
John

Have had the Aerosport power 0-375 for 7 years and logged 500 hours on it.Half bush/mountain territory and half cruise gentle flying.For cruise with a Prince 74” prop I run at 2100 RPM and get24litres/hour fuel burn.Engine has massive torque.I have 29” bush wheels and still cruise at the above figures at 78K GPS average.Have had no problem with the engine after sorting out the fuel jet initially which was too rich.Aerosport power were great on that occasion and sent me a brand new carb no charge.Static RPM 2375.Still minimum oil burn, maybe 1 litre/ 10 hour .With that prop I am well aft of the forward C of G limits and never run out of trim.Aircraft Javron /Backcountry cub.

[thaefeli]

See my Experimental O-320 ad in classifieds.
Tom