Conical vs Dynafocal

[Rupester]

In one of Tony Bingelis' books, he says some folks feel the dynafocal mount does a better job of isolating engine vibration from the rest of the structure than the older conical style. Bingelis himself doesn't seem to offer an opinion. Do any of you RVers have experience flying behind both? Could you tell the difference in vibration level between the two mounts?

(I'm just starting my engine search, and I'm wondering if the difference in isolation should push my engine selection toward dynafocal ...all other things being equal.)

Terry Ruprecht
Mahomet, IL
RV-9A QB fuse

[jclark]

Originally Posted by Rupester

In one of Tony Bingelis' books, he says some folks feel the dynafocal mount does a better job of isolating engine vibration from the rest of the structure than the older conical style. Bingelis himself doesn't seem to offer an opinion. Do any of you RVers have experience flying behind both? Could you tell the difference in vibration level between the two mounts?

(I'm just starting my engine search, and I'm wondering if the difference in isolation should push my engine selection toward dynafocal ...all other things being equal.)

Terry Ruprecht
Mahomet, IL
RV-9A QB fuse

Obviously either will work fine but if you have a CHOICE, go Dynafocal.
The bigger donuts seem to absorb more vibration.

With a perfect engine prop of ZERO vibration, it won't matter. But perfection is hard to achieve.

James

[Mel]

It's impossible to get an apples to apples comparison since no 2 engines have the exact same vibration characteristics. But the dynafocal definitely is better. How much, is anyone's guess. If you find a good deal on a conical mount engine, I wouldn't let that be a deal killer. Just have you prop dynamically balanced and fly on.

[combat404]

Is it possible to extend the exhaust pipes so they end behind the passenger compartment, rather than under your feet?

In a 2006 issue of the EAA magazine, there was a story about a man who spent 12 years restoring an old C-182. The article noted that he made a one inch thick fire wall, using two layers of ceramic and 1" of foam sound proofing. Has anyone done something like this?

The noise level in the cabin was 75 decibels, at cruise, with a 275 hp engine.

[gmcjetpilot]

Originally Posted by Rupester

In one of Tony Bingelis' books, he says some folks feel the dynafocal mount does a better job of isolating engine vibration from the rest of the structure than the older conical style. Bingelis himself doesn't seem to offer an opinion. Do any of you RVers have experience flying behind both? Could you tell the difference in vibration level between the two mounts?

(I'm just starting my engine search, and I'm wondering if the difference in isolation should push my engine selection toward dynafocal ...all other things being equal.)

Terry Ruprecht
Mahomet, IL
RV-9A QB fuse

Simple, first do a search of the archives in these forums on Dynafocal, Conical, Lord. I have wrote a few things on it.

Dynafocal is best, BUT if bargain hunting and you find a good deal in a conical mounted engine, that is NOT a show stopper. Again do a search on dynafocal, conical and Lord. If you are overhauling a conical engine you can have it converted for about (?) $500-$600.

I had a Conical mounted O320 in a RV-4 and a Dynafocal in another. Dynafocal is better.

Originally Posted by combat404

Is it possible to extend the exhaust pipes so they end behind the passenger compartment, rather than under your feet?

In a 2006 issue of the EAA magazine, there was a story about a man who spent 12 years restoring an old C-182. The article noted that he made a one inch thick fire wall, using two layers of ceramic and 1" of foam sound proofing. Has anyone done something like this?

The noise level in the cabin was 75 decibels, at cruise, with a 275 hp engine.

Good question, may I suggest you start a new thread with that question, or like I suggested to Terry Ruprecht above, SEARCH the archives. Play around with the search word or words: exhaust, floor vibration, vibration or combo of these or other words. Lots of info. If you find a thread and you like it but still have a question to ask, post it on that thread. That old thread will will appear as a new thread with all the previous posts. The beauty is it keeps the data base related to one topic. Happy info finding.

Some do complain of floor vibrations, but my input is added exhaust pipes hanging out and floor insulation adds drag and weight. If you have not flown a RV, than a head set is needed, probably louder than a typical 110 mph Cessna or piper.