Pa-18 io-360 200hp

[kaio_rangel]

Hey Guys !
I'm building my PA-18 in Brazil (North Land blueprints), and I'm doing a lot of upgrades on this project.
But I would love to hear from you guys about some of these modifications.

First of all, I'm building the Pa-18 with a Lycoming IO-360-A3B6 Angle Valve 200HP.
My first concern about this is weight and balance. The point I'm doing this is because I already have this engine I was going to use on a RV-7 and I changed plans.
Has anybody here built a PA-18 with this engine ? it is 33lbs wavier than a 180hp.
To help on the "weight" matter, I used all 4130 in the whole fuselage, probably saved a couple pounds.

I'm also planning to use the MT Propeller, composite, or a fixed pitch Catto Propeller, to help with w&b. But I'm not a huge fan of fixed pitch airplanes, there is no point that much power on a fixed pitch (my opinion) if you have to reduce the rpm right after take off using the throttle.

So, I need help guys. Would love to hear from somebody who have installed this engine. I have many questions about the engine mount as well.

Fly Safe Everyone!

[stewartb]

I have an IO-390 and constant speed on a dynafocal mount. My solo CG is a little forward. It behaves better with about 40# of tools and gear stuffed in back, which I’d carry anyway.

[skywagon8a]

I have an IO-360 180 hp with a dynafocal mount, plan on installing permanent ballast as far aft as possible. Using the ballast will give you better overall performance. The further aft, the less you will need. Yes, use the constant speed prop.

[aktango58]

Holy cow, that should be a climb monster!!

Bill Rusk has quite a write up on his build which included lots of engine weight loss items. Might be a good place to look.

[stewartb]

The 30# is attributed to larger cylinder heads (said to add 5# each) and a beefier crank and counterweight assembly. You can throw money at lightened ring gear support, lightweight sumps, etc, but the biggest weight impact those make is in lightening your wallet. Lots of guys add removable lead weights aft. Some have filled their tail posts with lead shot. I didn’t build my plane to fly empty so I prefer to balance with useful cargo, but there are many ways to skin that cat. In the end the added power usually overcomes the added weight and then some. Bottom line, if you want a plane to fly like a PA-11? Build a PA-11. If you want 200hp and a CS prop? Go for it. Just don’t expect it to feel like an -11.

[bob turner]

Got that right. They go straight up, but lose all their charm. Heavier is often not better unless your mission is straight up.

As I recall, the actual takeoff roll for a 180 fixed pitch Super Cub was quite a bit more than an 85 hp J-3. Once off the ground the deck angle was exhilarating!

[Bill Rusk]

"Has anybody here built a PA-18 with this engine ? it is 33lbs wavier than a 180hp".

Heavier than what? According to the TCDS the 0-360 can weigh from 258 pounds to 303 pounds.

I just spoke to a gent that did just what you are thinking about. He is so unhappy with the performance he is either going to sell it, or completely rebuild it.

If you are 33 pounds heavier than 303, then you add a dynafcal mount (20 pounds), FI (20 pounds), CS prop (20 to 50 pounds). You will quite likely be over 100 pounds heavier FWF than a more conservative lightweight set up.

In my humble opinion, don't build around the engine you have, build around around the engine you want. You can sell your 0-390 and use the money to buy the engine that will best meet your mission. If you really want the 390 just be advised you will want to build in a place in the tail to bolt in lead weights.

I have yet to meet the builder/pilot that was sorry he built it so light. Met a ton of guys that wished their cub was lighter.

Bill

[skywagon8a]

I have yet to meet the builder/pilot that was sorry he built it so light. Met a ton of guys that wished their cub was lighter.

Bill

Yes a light Cub is great. However, just put the proper ballast in the tail, it will fly great. It's all about CG control.

[stewartb]

I know a few guys with 240hp Cubs. None wants to go back to a standard Cub as their primary plane. Maybe for a fair weather flyer. It isn’t unlike Cessna 180s. What are the popular mods? More power, more prop, more wing, in that order. Ask the guys with stock 180s? They talk trash about the others. Internet 101. Separate the wheat from the chaff.

[bob turner]

That’s true. If your mission is carrying a load out of remote, very short strips, the more power the better. If your mission is to simulate such endeavors, you may get away with less power.

But if you enjoy flying for fun, and do not need to be “on the edge,” the monster Cubs and 180s are a lot less fun to fly.

Reminds me of the Helio - very good slow speed short field load hauler, but flew a lot like a truck without power steering.

[stewartb]

A young friend just bought a Helio. He’s over the moon. There are a lot of missions for pilots. To each their own.

[mam90]

Yep. Bob, everyone knows how you feel about cub mods, light cubs, etc… Just because you think they fly better light doesn’t mean everyone agrees with that line of thought. I’m one that doesn’t agree, but your years of voicing your opinion are duly noted….

[cubdriver2]

Yep. Bob, everyone knows how you feel about cub mods, light cubs, etc… Just because you think they fly better light doesn’t mean everyone agrees with that line of thought. I’m one that doesn’t agree, but your years of voicing your opinion are duly noted….

Said the guy with a lite Pa11

Glenn

[mam90]

Said the guy with a lite Pa11

Glenn

With every mod and STC I could find!

[supercrow]

I have owned quite a few over the last 50 years, including the light ones, and I love them. But if balanced correctly, the higher horsepower heavier ones fly just as nicely it’s all about balance.

[bob turner]

I can see I will have to go back to saying “opinion” on each post. I really don’t have all that much experience with heavy aircraft, and admit to only flying two CC 180 Cubs. So, not an expert. I do have 5000 tach hours in my own Cub.

I have barely enough experience that I just refused to instruct a low time tailwheel pilot in his 450 Stearman, mostly because of weight and inertia considerations. I am sure it flies fine - but weight and inertia affect handling, and I shall not even try. I am fairly low time in the 220 Stearman, barely closing in on a thousand hours - but it is plenty heavy enough.

I stand by my opinion -the mission should drive the power plant choice- and indeed the airframe choice.

Opinion.

[stewartb]

The OP asked for pireps about installing an angle valve Lycoming on a Cub. Simple question. Those who have, say aye.

Aye.

[peterdillon]

If your not in certified territory its easy to get over 200hp with basic mods out of a 320 without sacrificing reliability, put a CS MT on it and win every battle Lighter than a cub with a borer, better TO performance than a 180 with any prop, less fuel burn per mile than a std cub while cruising at well over 100 mph.

[Olibuilt]

If your not in certified territory its easy to get over 200hp with basic mods out of a 320

I would like to know if my 360 can be modified has easily? What mod are you talking about?

Thanks for sharing

[stewartb]

Find a shop with sketchy dyno practices. Your 360 can make as much horsepower as you want to pay for.

Angle valve heads use a better combustion chamber shape and better valve positioning. They breathe better. That’s why they make more power. The added number and size of cooling fins were needed to keep the cylinders cool. The best way to add power with a typical direct drive engine at 2700 RPM is to add displacement or increase manifold pressure (supercharge.)

[peterdillon]

If you are just having fun flying around the patch the larger displacement engines are the easiest and cheapest way to get better take off performance.
Our experience if your doing some serious distances the poor range of a cub with 36 gal fuel just gets worse with the 360's.

[Olibuilt]

Our experience if your doing some serious distances the poor range of a cub with 36 gal fuel just gets worse with the 360's.

Mine has 61 gal, so I’m in for a long ride…

But I would really like to know what easy mod would make a 320 to 200hp?

[peterdillon]

Thats great you have the big tanks. The old aircraft engines designs are antiquated technology as Stewart talks about in a previous post. 75 year old tractor technology at best. Just improving the intake and exhaust port flow in the cylinders and balancing all the components properly allows you to raise the compression and max rpm and still maintain full tbo. Obviously all not legal in a certified engine. The real high performance 320 engines like the big name racers are running 3500 rpm with special light weight pistons making 240 hp. Properly done with all the right components fully matched you only need to run around 2850 rpm to make 200hp. According to the people in the know a properly built 320 running at 3000 rpm will probably outlast a certified one. The smaller the displacement the easier it is to run higher rpm so the bullet proof 320 is a perfect one to mod. So its not just bolt on a blower but at rebuild time get a rebuilder that really knows what he is doing an get the full meal deal like roller tappets, o-ring cases, light weight rods, cylinder rework, special valve springs etc etc etc.