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Updating an A-65?

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Pops

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Is there a sneaky way to hot rod an A65? Maybe drop in a longer throw crank out of something? I ask because there’s a homebuilt Champ at my home field that just walks away from all the other A65 powered planes, including other Champs. It even out-revs an 85hp Cub on the same prop. We know where the engine came from (another Champ crushed in a hangar collapse) but apart from giving strong oil pressure and not making metal we haven’t dug too deep into the engine itself.
Look at link in post #12.
 

Armilite

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Is there a sneaky way to hot rod an A65? Maybe drop in a longer throw crank out of something? I ask because there’s a homebuilt Champ at my home field that just walks away from all the other A65 powered planes, including other Champs. It even out-revs an 85hp Cub on the same prop. We know where the engine came from (another Champ crushed in a hangar collapse) but apart from giving strong oil pressure and not making metal we haven’t dug too deep into the engine itself.
===========================

Since everybody uses different Brand Name & Lenght and Number of Blades Props, everything you do can gain you some more hp. Most Upgrades are done during a Rebuild.

1. Raise CR. Bolt-On New Pistons!
2. Better Cam. Bolt-On!
3. Porting & Polishing. Labor & Grinding
4. Bigger Valves. Machining and Bolt-On Parts.
5. Use Higher rpm.
6. Use the different Engine Coatings.
7. Use EFI.
8. Add a Turbo. Bolt-On Item.
 

TFF

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You put a A-75 prop on it. A-75 prop is slightly less diameter which lets it spin faster. The gain in thrust with more rpm is more than the loss of the diameter. A-75 is updated to handle the RPM. Technically it’s not legal, but you have to put all the pieces together to catch it.
 

n3puppy

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You put a A-75 prop on it. A-75 prop is slightly less diameter which lets it spin faster. The gain in thrust with more rpm is more than the loss of the diameter. A-75 is updated to handle the RPM. Technically it’s not legal, but you have to put all the pieces together to catch it.
Yup - that's what the local guys do - A75 prop for more rpm. My Aeronca Chief had a "Climb Prop" that was suspiciously like a A75 prop if you measured it - but was marked as a "Legal" A65 prop

Continental service bulletin lists all the parts needed to "Officially" turn a A65 into a A75. Most felt the item on the list worth swapping were the drilled rods for better oiling at higher rpm
Some guys went with the pistons too but not always
6B026F8B-346D-44E3-A961-ACCFDD10BFFE.jpeg
 
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Pops

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I think I have a set of 80 hp pistons, but everyone says they are heavy and best not to used them. Also might have a set of 75 HP rods. Oil holes in large end.

Dan
 

PTAirco

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I think I have a set of 80 hp pistons, but everyone says they are heavy and best not to used them. Also might have a set of 75 HP rods. Oil holes in large end.

Dan
I have also heard that those people who own an A85 (not many) are quite happy with the way it runs. I'd be curious to build one just to see how it does.Stritcly experimental, of course....
 

crkckr

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I may be sticking my foot in my mouth here but if I remember correctly (tain't necessarily so, it's been a long, long time) to upgrade an A-65 to an A-75, all that was needed was new pistons, which had more rings than the A-65 pistons. Also, you had to drill a small hole in the rod caps (I believe it was .125 but my memory isn't what it was last week!) for better oil slinging. This would raise your RPM limits, which was about all it did, but it gave you a few extra HP. I did the upgrade in A&P school on my own A-65 way back in the stone ages (early '70's) instead of tearing down an IO540 the school had a bunch of. You should have seen the administration hit the ceiling when they found out I was hand propping the thing on an old engine stand the school had way, way out in the back! But I convinced them I knew what I was doing (with help from an instructor, of course) and I actually got the thing running pretty good. I don't know squat about IO540's but I redid everything on that A-65/75 and got her down to new specs!
Cheers,
crkckr
 

rv7charlie

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You put a A-75 prop on it. A-75 prop is slightly less diameter which lets it spin faster. The gain in thrust with more rpm is more than the loss of the diameter. A-75 is updated to handle the RPM. Technically it’s not legal, but you have to put all the pieces together to catch it.
My choice would be same (or more) diameter; less pitch. Unless the plane is some kind of 'unicorn' (150kt+ on 65HP), the diameter will never hurt cruise, and giving up diameter may well offset most of the HP gains for climb (low speed mass flow issues). With max rpm in the 2400-2500 range, there's not a lot of risk for the tips going transonic. ;-)

Charlie
 

TFF

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My examples are props certified to various Aeroncas. Certified switcheroo. They are on the type certificate, just wrong model. Although big diameter is nice, reducing pitch on something like a champ gets close to binary speed range, stall or not stall.
 

rv7charlie

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Interesting. The Luscombe 8A that taught me to fly must be a lot cleaner. IIRC, rated rpm of an A65 is 2300 rpm. I flew it on cross countries at well north of 2400 rpm & over 100 mph on a regular basis, and would reach pattern altitude near mid-field on a 5400' runway.
 

Pops

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My grandson received a share in a Luscombe 8A project when he was 16 years old and helped restore it with an A-I that also owned a share. It would fly 105 mph at WOT on the A-65. I did the finish painting on the project . If you can shut the doors, it will haul it. Fun airplane.
 

Tiger Tim

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I played safety pilot in a Luscombe this summer and I have to say I was really impressed by it. I was expecting an experience similar to a Cessna 150 and somehow just a little worse but I found it was a delightful little performer for what it was.
 

Pops

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I played safety pilot in a Luscombe this summer and I have to say I was really impressed by it. I was expecting an experience similar to a Cessna 150 and somehow just a little worse but I found it was a delightful little performer for what it was.
And there is an STC for a Lyc- 320 engine. A Cont- 0-200 non-electric would be nice.
 

rv7charlie

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There was a 320 powered Luscombe local to me back before I started flying. Word was it ruins the plane. I agree about the O-200, though it's hardly needed. :)
 

Pops

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The Luscombe and the T-Craft does a lot with a Cont A-65 engine.
 

rv7charlie

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The only thing that comes to mind that benefits from that kind of HP increase is a Swift. But that's because it was so radically underpowered 'out of the box'. I was a partner in a 200 HP version for a while (great plane) and flew a 210 HP, and rode in a stock 85 HP. Once. Don't really want to do it again. 220 lbs & 160 lbs in it, and it barely cleared the trees at the end of a 4800' grass strip.

Charlie
 
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