Hi folks,
What is the current opinion on the McCulloch 72 and 90 hp drone engines?
I’ve read just about every reference to them here and over on the Rotary forum I could find.
General consensus is:
“A Mac only comes with one guarantee. It will quit. Most likely when you need it most.”
And:
“A Mac? Put it on an airboat or some other application that won't ever carry living things off the ground. Or, use it as an anchor for a bigger boat. They were designed to carry an unmanned target drone high enough to get shot down, but not expected to last through a landing, and certainly not man-rated. If there were a competition for engines most likely to quit when least convenient, it would take best in show.”
On the other hand, two quotes I found on the forum here stand out:
and
Someone wants to sell me a good running Mac 90 at a reasonable price. He states:
“Already got the Mac engine upgraded. I use a VW distributor and coil for ignition. I use VW bug exhaust baffles. I use two Harley 40mm clone carbs for the 90. Mikuni clones are cheap from Amazon. Starts and runs great… Bensens with Mac engines have done a lot of cross country flights. Some designs use ducting over the exhaust ports instead of open air with mufflers like the original Bensen design, to make the prop pull air through the cylinder fins, maybe that prevents overheating? The gyro trainer I flew did the same thing with a Lycoming aircraft engine to keep it cool, it works. So I have low cost ignition, low cost prerotater, low cost carbs … And I can use a WWI wood propeller that costs $200 new.”
So has he addressed the concerns in the first screen capture image above? Or does the engine need torn down to inspect and replace the bearings, if necessary?
He would be selling it to me with a pusher ultralight I’m considering buying from him. It’s certainly within the engine weight limits for the aircraft but twice the necessary hp. But I’m a big guy so he says the extra hp wouldn’t hurt, especially since I wouldn’t need to run it hard in this application in general.
I told him to get the Mac mounted and send me a video of it running and him flying it in that ultralight and I’d buy it.
If I don’t feel comfortable with it, I can always resell it as some folks are still looking for running Mac 90s apparently.
What is the current opinion on the McCulloch 72 and 90 hp drone engines?
I’ve read just about every reference to them here and over on the Rotary forum I could find.
General consensus is:
“A Mac only comes with one guarantee. It will quit. Most likely when you need it most.”
And:
“A Mac? Put it on an airboat or some other application that won't ever carry living things off the ground. Or, use it as an anchor for a bigger boat. They were designed to carry an unmanned target drone high enough to get shot down, but not expected to last through a landing, and certainly not man-rated. If there were a competition for engines most likely to quit when least convenient, it would take best in show.”
On the other hand, two quotes I found on the forum here stand out:
and
Someone wants to sell me a good running Mac 90 at a reasonable price. He states:
“Already got the Mac engine upgraded. I use a VW distributor and coil for ignition. I use VW bug exhaust baffles. I use two Harley 40mm clone carbs for the 90. Mikuni clones are cheap from Amazon. Starts and runs great… Bensens with Mac engines have done a lot of cross country flights. Some designs use ducting over the exhaust ports instead of open air with mufflers like the original Bensen design, to make the prop pull air through the cylinder fins, maybe that prevents overheating? The gyro trainer I flew did the same thing with a Lycoming aircraft engine to keep it cool, it works. So I have low cost ignition, low cost prerotater, low cost carbs … And I can use a WWI wood propeller that costs $200 new.”
So has he addressed the concerns in the first screen capture image above? Or does the engine need torn down to inspect and replace the bearings, if necessary?
He would be selling it to me with a pusher ultralight I’m considering buying from him. It’s certainly within the engine weight limits for the aircraft but twice the necessary hp. But I’m a big guy so he says the extra hp wouldn’t hurt, especially since I wouldn’t need to run it hard in this application in general.
I told him to get the Mac mounted and send me a video of it running and him flying it in that ultralight and I’d buy it.
If I don’t feel comfortable with it, I can always resell it as some folks are still looking for running Mac 90s apparently.
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