Mark Landoll Harmonic Dampener question

[RVbySDI]

Originally Posted by Dmadd

Mine was the solid ring. He had both available, and my understanding (from Mr Landoll) was wood props only needed the low tech version. It just added a bit a mass to the prop arc, which smoothed it out. Without it, for example, the prop would stop instantly when shut down. (not specifically WHY I used it, but an indicator of how it reacted)
I installed it because I didn't like the "bang bang bang" of the power pulses at idle... Even in the pattern at idle it did it. (MT prop weighed almost nothing) Metal props would NOT have this issue...
It did not slow down engine acceleration or deceleration at all. (very fast response with light prop)
The hollow ring, with the material inside it, was for prop balance issues as well as the harmonic component.
I liked the product. It did exactly what he said it would.

Hope this helps...

Originally Posted by Sdemeyer

I installed one on my mustang ii not too long ago strictly for w&b reasons. It weighs 11 pounds and bolts to the flywheel. I did not notice any difference in vibration or smoothness but it allowed me to be able to carry baggage. The bolt heads are very close to the starter so if one ever comes loose, it's going to be a bad day for sure. Overall I am happy with it. My M2 has an o320 and sterba wood prop.

Mark is an active member of our EAA chapter (EAA UL98). He discussed his dampener with me prior to my build completion once I told him I was installing a 3-blade Catto prop. He had mentioned all of the issues posted here and others as to why I would need a dampener. My prop weighed in at 12 lbs. the Sabre spacer weighed in at 8.5 lbs. I decided against adding the plate as it would have added additional weight on the nose of my 'A' model. The very place I could least afford to have more weight. Might I say the least of which anyone building an 'A' model could afford additional weight. in 5.5 years of flight I have never missed it. The Catto is extremely smooth. It does not BANG-BANG-BANG at shutdown. It idles smoothly with no noticeable pulsing. The prop/engine does not display any of the negative aspects that others have reported.

I am happy with the decision I made in NOT installing additional weight on the nose with Mark's dampener. I personally think it a bit crazy to strive toward building as light as possible and then throw some chunk of metal or some such item to add weight and increase the weight and alter the C/G after carefully building light and balanced.

Originally Posted by Wally

I also have a Catto 3 blade prop. Do you by any chance have instructions for installation? I know the dampener bolts to the ring gear but I also have a steel plate that seems to belong on the front of the dampener with the center against the ring gear. However, talked to Mark Landoll and he said it had something to do with the spinner. My guess is I wasn't communicating very clearly.

Wally

If you have not already flown with the Catto 3 blade prop I suggest you do so before installing Mark's dampener. As I attest above my experience with my 9A is that with the Catto 3 blade it is not needed.

[Wally]

May just do that. I bought from a friend who had a 4. He added not only the harmonic dampener but a 12 lb steel ring to get is CG where he could stay within envelope with a rear seat passenger. I also have the steel ring but do not plan to add that until and if it is deemed necessary. The steel plate I have is a total ?????

He sold his -4 to a guy who planned to use a metal prop so they removed it before sale. Unfortunately, he is now suffering from dementia so unable to answer my question.

[Wally]

Thanks Steve! I think I will go with your suggestion. My guess is that the CG on an A model is not as big an issue as on a 4.

Talked to Mark but he was not able to help with the steel plate. Could well have been my communication. Was great to talk to him! Met him at Oshkosh probably 15 years or so. Also talked to Inovators West, who manufactures them but they have never seen on installed on an aircraft. Big in racing engines.

Wally
RV-4 getting close!

[Neal@F14]

My 6 was built with the solid ring and originally an Aymar-Demuth wood prop. I left the ring on when I installed the Sensenich GA prop because I need the weight up front for CG reasons. It sure is smooth with this prop, like "turbine smooth". I like it.

[RVbySDI]

Originally Posted by Wally

Thanks Steve! I think I will go with your suggestion. My guess is that the CG on an A model is not as big an issue as on a 4.

Talked to Mark but he was not able to help with the steel plate. Could well have been my communication. Was great to talk to him! Met him at Oshkosh probably 15 years or so. Also talked to Inovators West, who manufactures them but they have never seen on installed on an aircraft. Big in racing engines.

Wally
RV-4 getting close!

You may be surprised at how smooth Catto props are just bolting them on and flying. They are indeed a work of art!

[glenn654]

Wally,

The steel plate you have is the "Aerobatic Plate".

I had a Landoll Harmonic Balancer with the aerobatic plate on my -4 which I flew for 10 yrs before selling.

The aerobatic plate attaches to the front of the balancer and behind the prop hub and will bolt to the ring around it's perimeter. I believe the point is to strengthen the balancer by sandwiching it that way.

I think it was a good addition but no scientific evidence.

Glenn

[uk_figs]

I have the landoll ring and the sabre steel spacer with a Catto 3 blade prop on my -7 primarily for the CG reasons mentioned in this (and other threads)

The -7 tends toward aft CG with two up and 100lbs of baggage as the CG moved aft with fuel burn. The -7 was targeted for a typical Hartzell CS prop which weighs 40+ lbs and my original sensenich metal prop assembly weighted 42lbs. When I switched to the Catto which weighs about 12 lbs it made a big difference to the W&B calculations if fully loaded as the weight all came off the nose. In my case I went with the landoll and sabre crush plate rings to put the weight back on and I have not regretted the decision, the Catto is very smooth anyway but my motor also runs smoothly at 800 rpm at idle.

As far as the CG/W&B last year we had two big guys and full camping gear etc for oshkosh and we were good down to 10 gals inside the aft CG limit which is good for 4 hour legs (at which I would need a bio break anyway)

Like everything on the RV there are many choices and I am happy with mine.
Figs

[sibriggs]

I have a Landoll Balancer with the bolts and a round disc that seems to fit over the entire unit after it's bolted to the flywheel. The disc has small holes that correspond to the prop hub bolt pattern.

I seen pictures of Landoll installations that did not include this disc and another that did.

I don't have any instructions on the Landoll installation or the disc, can anyone help me understand it's purpose and if it's needed.

Thanks, Steve Briggs

[sibriggs]

I have a Landoll Balancer with the bolts and a round disc that seems to fit over the entire unit after it's bolted to the flywheel. The disc has small holes that correspond to the prop hub bolt pattern.

I seen pictures of Landoll installations that did not include this disc and another that did.

I don't have any instructions on the Landoll installation or the disc, can anyone help me understand it's purpose and if it's needed.

Thanks, Steve Briggs