Prop position?

[dwilfong]

I need to not talk so much..........................LOL

Could you balance the eng with a small rotational mass with the different pitch of the prop??????????????

How about a screew prop that loads the eng proportionally in the rotation with very small rotational mass...................................

O crap here we go again time to pull it out from under the bed.........................LOL

DING DING DING round two...............................

Andy don't answer the phone please......................I need to finish my Vector first.............................

 

[KenOlvis]

I was told about indexing the prop in the 70's when running hard shafts to help the motor. Wasn't given the theory behind it I figured it was to find a good balance point.I always set the prop blades at 3 an 9 with piston set at bottom of the stroke that way I had the same refers when testing.

 

[stan simpson iv]

Ok...next question on the prop position. Would it be "ANY" different between a "High" lifting prop versus the new ABC props??

 

[Alan Elzer]

Guy's I cosine myself STILL a beginner..... But I'm very glad I started this thread....it's been very interesting at ALL the comments.

THANKS GUYS FOR ALL THE TECHNICAL STUFF.

Sent from my SAMSUNG-SM-N900A using Tapatalk

 

[Michael Caruso]

Guy's I cosine myself STILL a beginner..... But I'm very glad I started this thread....it's been very interesting at ALL the comments.

THANKS GUYS FOR ALL THE TECHNICAL STUFF.

Sent from my SAMSUNG-SM-N900A using Tapatalk

Guy's,

I am along for the ride and a once was a simple hobby, has turned into the Physics class that I missed 50 years ago. I love and thank you all for sharing.

Mike

 

[Marty Davis]

Charles & Christian,

Thanks for two very good post explaining what takes place.

JA

Yes, Christian and Charles hit the nail on the head.

The inertia of the rotating elements impart a relatively smooth and even power flow to the prop and keep the crankshaft speed relatively constant in one revolution.

It is correct that crankshaft speed is not constant in one revolution. In a single cylinder engine the rotating mass effects that ever changing crankshaft speed.

More mass = more constant.

Marty's theory would hold more water (no pun intended) if the rotating mass was extremely small.

And to that degree I do believe there is merit in his theory, if the rotating mass was very small.

Sounds like my friend David Wilfong has been talking to Andy Brown on the phone.

Ah yes, I remember now! We had this complete conversation on the phone about a year ago and my conversation

to David included Marty's theory, variable crankshaft speed, very light rotating mass

and how I think a single bladed prop could take advantage of Marty's theory.

I do have experience with single bladed props.

A side point.....

When I ran SAW back in the 70's and 80's we ALWAYS used a heavy flywheel. Don's question about how to help launch is also solved to a large extent by a heavy flywheel. Probably would not be the greatest for a small pond and quick acceleration needed.

Marty,

I noticed that as well. I had a few ops 67s that had brass flywheels. With the brass my ops 65 seemed to keep on trucking at speed where the aluminum flywheel did not seem to be as smooth. I experimented with all kinds flywheel weights by turning down the brass flywheel on a lathe. I wish we had radar guns back then.

John

I compared aluminum to steel back in the late 70's in a Pinckert Gator. Steel carried much more corner speed while running tight on the buoys. The aluminum would drop a lot of speed in the corner and sometimes fall off pipe near the exit buoy.

The effects of gyroscopic precession on hull handling is also a consideration.

Andy:

Back then our turn fins and turning ability were VERY poor and a lot of rudder deflection was needed to turn. Now with great turn fins, maybe this is not nearly as important.

 

[Andy Brown]

Charles & Christian,

Thanks for two very good post explaining what takes place.

JA

Yes, Christian and Charles hit the nail on the head.

The inertia of the rotating elements impart a relatively smooth and even power flow to the prop and keep the crankshaft speed relatively constant in one revolution.

It is correct that crankshaft speed is not constant in one revolution. In a single cylinder engine the rotating mass effects that ever changing crankshaft speed.

More mass = more constant.

Marty's theory would hold more water (no pun intended) if the rotating mass was extremely small.

And to that degree I do believe there is merit in his theory, if the rotating mass was very small.

Sounds like my friend David Wilfong has been talking to Andy Brown on the phone.

Ah yes, I remember now! We had this complete conversation on the phone about a year ago and my conversation

to David included Marty's theory, variable crankshaft speed, very light rotating mass

and how I think a single bladed prop could take advantage of Marty's theory.

I do have experience with single bladed props.

A side point.....

When I ran SAW back in the 70's and 80's we ALWAYS used a heavy flywheel. Don's question about how to help launch is also solved to a large extent by a heavy flywheel. Probably would not be the greatest for a small pond and quick acceleration needed.

Marty,

I noticed that as well. I had a few ops 67s that had brass flywheels. With the brass my ops 65 seemed to keep on trucking at speed where the aluminum flywheel did not seem to be as smooth. I experimented with all kinds flywheel weights by turning down the brass flywheel on a lathe. I wish we had radar guns back then.

John

I compared aluminum to steel back in the late 70's in a Pinckert Gator. Steel carried much more corner speed while running tight on the buoys. The aluminum would drop a lot of speed in the corner and sometimes fall off pipe near the exit buoy.

The effects of gyroscopic precession on hull handling is also a consideration.

Andy:

Back then our turn fins and turning ability were VERY poor and a lot of rudder deflection was needed to turn. Now with great turn fins, maybe this is not nearly as important.

Yes Marty. For the last 2 or 3 years I have been testing "microscopic" aluminum flywheels (pully) with good success with normal heat race prop set ups.

But if I try to run the biggest possible prop for oval record set up the engine will fall off near the exit of the turn.

My mind has momentarily revisited the thought of a heavy flywheel, but my better plan is to reduce cornering drag.

However, corner drag will always be greater than SAW drag so in the end there could still be merit in heavy flywheel.

 

[Marty Davis]

Charles & Christian,

Thanks for two very good post explaining what takes place.

JA

Yes, Christian and Charles hit the nail on the head.

The inertia of the rotating elements impart a relatively smooth and even power flow to the prop and keep the crankshaft speed relatively constant in one revolution.

It is correct that crankshaft speed is not constant in one revolution. In a single cylinder engine the rotating mass effects that ever changing crankshaft speed.

More mass = more constant.

Marty's theory would hold more water (no pun intended) if the rotating mass was extremely small.

And to that degree I do believe there is merit in his theory, if the rotating mass was very small.

Sounds like my friend David Wilfong has been talking to Andy Brown on the phone.

Ah yes, I remember now! We had this complete conversation on the phone about a year ago and my conversation

to David included Marty's theory, variable crankshaft speed, very light rotating mass

and how I think a single bladed prop could take advantage of Marty's theory.

I do have experience with single bladed props.

A side point.....

When I ran SAW back in the 70's and 80's we ALWAYS used a heavy flywheel. Don's question about how to help launch is also solved to a large extent by a heavy flywheel. Probably would not be the greatest for a small pond and quick acceleration needed.

Marty,

I noticed that as well. I had a few ops 67s that had brass flywheels. With the brass my ops 65 seemed to keep on trucking at speed where the aluminum flywheel did not seem to be as smooth. I experimented with all kinds flywheel weights by turning down the brass flywheel on a lathe. I wish we had radar guns back then.

John

I compared aluminum to steel back in the late 70's in a Pinckert Gator. Steel carried much more corner speed while running tight on the buoys. The aluminum would drop a lot of speed in the corner and sometimes fall off pipe near the exit buoy.

The effects of gyroscopic precession on hull handling is also a consideration.

Andy:

Back then our turn fins and turning ability were VERY poor and a lot of rudder deflection was needed to turn. Now with great turn fins, maybe this is not nearly as important.

Yes Marty. For the last 2 or 3 years I have been testing "microscopic" aluminum flywheels (pully) with good success with normal heat race prop set ups.

But if I try to run the biggest possible prop for oval record set up the engine will fall off near the exit of the turn.

My mind has momentarily revisited the thought of a heavy flywheel, but my better plan is to reduce cornering drag.

However, corner drag will always be greater than SAW drag so in the end there could still be merit in heavy flywheel.

How about mixing the Rudder with the Mixture control. I have been doing that for exactly that reason (exit of the turn).

 

[Andy Brown]

Charles & Christian,

Thanks for two very good post explaining what takes place.

JA

Yes, Christian and Charles hit the nail on the head.

The inertia of the rotating elements impart a relatively smooth and even power flow to the prop and keep the crankshaft speed relatively constant in one revolution.

It is correct that crankshaft speed is not constant in one revolution. In a single cylinder engine the rotating mass effects that ever changing crankshaft speed.

More mass = more constant.

Marty's theory would hold more water (no pun intended) if the rotating mass was extremely small.

And to that degree I do believe there is merit in his theory, if the rotating mass was very small.

Sounds like my friend David Wilfong has been talking to Andy Brown on the phone.

Ah yes, I remember now! We had this complete conversation on the phone about a year ago and my conversation

to David included Marty's theory, variable crankshaft speed, very light rotating mass

and how I think a single bladed prop could take advantage of Marty's theory.

I do have experience with single bladed props.

A side point.....

When I ran SAW back in the 70's and 80's we ALWAYS used a heavy flywheel. Don's question about how to help launch is also solved to a large extent by a heavy flywheel. Probably would not be the greatest for a small pond and quick acceleration needed.

Marty,

I noticed that as well. I had a few ops 67s that had brass flywheels. With the brass my ops 65 seemed to keep on trucking at speed where the aluminum flywheel did not seem to be as smooth. I experimented with all kinds flywheel weights by turning down the brass flywheel on a lathe. I wish we had radar guns back then.

John

I compared aluminum to steel back in the late 70's in a Pinckert Gator. Steel carried much more corner speed while running tight on the buoys. The aluminum would drop a lot of speed in the corner and sometimes fall off pipe near the exit buoy.

The effects of gyroscopic precession on hull handling is also a consideration.

Andy:

Back then our turn fins and turning ability were VERY poor and a lot of rudder deflection was needed to turn. Now with great turn fins, maybe this is not nearly as important.

Yes Marty. For the last 2 or 3 years I have been testing "microscopic" aluminum flywheels (pully) with good success with normal heat race prop set ups.

But if I try to run the biggest possible prop for oval record set up the engine will fall off near the exit of the turn.

My mind has momentarily revisited the thought of a heavy flywheel, but my better plan is to reduce cornering drag.

However, corner drag will always be greater than SAW drag so in the end there could still be merit in heavy flywheel.

How about mixing the Rudder with the Mixture control. I have been doing that for exactly that reason (exit of the turn).

I do that Marty. It helps but not the complete cure.

 

[JoachimRuess]

Does anybody think about lengthening the pipe in the corners??

The endurence guys here in Europe do so. Especially in the smaller engines category.

Joachim

 

[Marty Davis]

Does anybody think about lengthening the pipe in the corners??

The endurence guys here in Europe do so. Especially in the smaller engines category.

Joachim

Joachim:

I have known about this for 30 years + but decided that it was to much of a mechanical exercise for me. I know it works and have seen it done, just more complexity than I want.

I can't keep up with all the complex items to add more....

 

[Michael Costanzo]

tried a remotely operated pipe 25 years ago and was not worth the hassle. if you build a fast,good handling boat and you can drive,you will be very succesfull.

 

[JoachimRuess]

Marty and Michael:

I hope that my friend is posting here his simple construction in his endurance boat and showed some pictures.

In this time it is easy with mixing the steering servo with the pipe servo.

Our experience is worth to give it a try.

Joachim

 

[Mark Stein]

Guess I am gonna have to get rid of the square drive on my boat so I can hang with you fast guys.

 

[Mark Stein]

You guys got me thinking about all the sq drive collets or shims or clocked cables I would need to clock with my set up.. wow

 

[Terry Keeley]

You guys got me thinking about all the sq drive collets or shims or clocked cables I would need to clock with my set up.. wow

Don't touch that boat! Lol!