.21 hydro propellors, and the magic

[Mike Larson]

Lets stimulate an otherwise boring day..... Why... is it that the cup ratio from 3.2 to 3.6 seems to be the magic numbers commonly run on current .21 props?.... Power to weight on the hull, motor to power to weight, all functions combined, what?...

reason asked is.... I've this box of props..... and while i've tested, retested, thrown, rowed, puked, needled, and otherwise ran my hulls, i'm always back stuck on the 3.4 prop for the best reliabilty... ie, throw it, and it goes, and fast......

While i'm not at all ignorant and constantly learning, a factory 1450, or 50x69, H5 or 7, will of course move something, and possibly well, with a range of props, stock, backcut, and prepared, what is it with the 3.2 to 3.6 46mm range that does it?.....

All else being equal, boat A pulled a 3.8 this spring in great air, with not much speed gained..... Boat A then degenerated through the test season, puking on 3.8, and pulling 3.4 all season long with ease, and consistent speed as always had recorded.....

having a small range of propellors, while nice, and a given pitch/cup doing well is nice, things ever changing is frustrating at best........

would you, do you..... cup them all around 3.2 to 4, and finite test from there, save up that massive 4.0 just for the spring, and fall, or work from around 3.2 to 6, and find THE magic one...... and copy it?......

question arising, that, as i'm sure we all have a little box of props that have little use ... ie; it wont pull that one, it wont pull that one, well it pulled that one this spring in great air, that one is junk, and wasting effort and time better spent trying to gain.......

winter's coming.... i'll be looking to fine tune a bunch of berylium junk..... searching for the magic, looking to gain.....

what is it, around that possibly being, most given .21 hydros weigh in around 4 lbs, and the given power output of a common .21 inboard motor that 3.2 to 4 or 6, are the norm.... how do you look for your pinnacle in any given prop/boat combination?...

Boat A ended the test season right back on 3.4 where I struggled all around it with little gain...... heat raced OK, but, as far as i was concerned it's a middle of the pack boat, ( great!)... but all i really accomplished was a little more wear on the motor, a lot of burned nitro, and some time and enjoyment invested.....

i'd like to come out in the spring with a positive jump in testing, a reworked box of little razor blades to spin, AND GAIN.......

otherwise.... i'm just burning nitro...... lotsa serious .21 guys around.... help me keep up..... mike

as a genera

 

[Scott Schneider]

.21 nitro riggers are about as tough a class to excel in as it gets. The smallest details remain small and **** near undiscerning in the big picture looked at individually .... So

Start with the hull and sponsons, ride surfaces flat and true, alignments spot on, aero & hydro dynamics delt with to your best ability and access to learning and understanding really good from great ?

Know you engine !! ...If your frosting up plugs, combustion chambers and pistons your losing power !! lean may be mean, but an efficient running engine does neither !!

Prop load engine so ENGINE can pull the load consistently giving your best average, then learn to get better starts and drive the low lanes kissing boeys

Last is pipe choice, with it's internal back pressure adjusted and played with and overall operating temperatures of the entire engine package dealt with and made stable as you can.

* Those who seem to have a magic bullet in a lot of cases actually do !! ... they have mastered all the little things that once added up best those who have not

 

[shoboat]

Mike,

It is the motor,pipe,and propeller combinations that make them go.

A great set up is very important though. Most are running too much

propeller on their motors, which never allows them to get to the RPM level

that it takes to go faster. The RPM and Center Of Blade Pitch is going

to determine your set up and the speeds that you will achieve with your

model. I can tell you that there is still a lot of performance in the

motor and fuel system that you may still be missing. We constantly test

new ideas and(old ones again)and we are starting to make big gains once

again. I can tell you that the JAE 12 and 21 boats will help you get more

out of your set up than most other hulls on the market. Glad you are back

having fun in the hobby. We have a friend up in Canada

that tells us: "It ain't as easy as it looks" and I can

tell you that is a very accurate statement. Good Luck!!!

Have Fun Testing,

Mark Sholund

 

[TERMINATOR]

Mike,

It is the motor,pipe,and propeller combinations that make them go.

A great set up is very important though. Most are running too much

propeller on their motors, which never allows them to get to the RPM level

that it takes to go faster. The RPM and Center Of Blade Pitch is going

to determine your set up and the speeds that you will achieve with your

model. I can tell you that there is still a lot of performance in the

motor and fuel system that you may still be missing. We constantly test

new ideas and(old ones again)and we are starting to make big gains once

again. I can tell you that the JAE 12 and 21 boats will help you get more

out of your set up than most other hulls on the market. Glad you are back

having fun in the hobby. We have a friend up in Canada

that tells us: "It ain't as easy as it looks" and I can

tell you that is a very accurate statement. Good Luck!!!

Have Fun Testing,

Mark Sholund

mark you did a prop for me i think it was at 3.8 cup and i think we can go 4.0 on my nova 5 port, mine pulls like hell so let me know when we can do that one..1450 that is 4.0 . mike i have a limited amount of knowledge but chris and i tested one day and saw marginal gains from props ranging from 3.2 to 3.6 and i tried that 3.8 and it still launched with ease and hauled the mail, i did find with my sport 20 and a a 1450 with 3.6 would run it till it blew off at around 65 -68 range or till it took a plug.. put the same needle setting and a 1445 cupped up and it would run all day probably 4 mph slower but it would go like hell , hoping the same combo works on my new sport 20 im building..learnign how much a prop loads and unloads a motor is amazing and i look forward to making new discoveries next season.

tk

 

[shoboat]

Terry,

When you and Chris were testing the 1450's @ 3.21" to 3.60" cupped propellers,

did you run the same pipe length? You need to shorten your pipe with less cup

or you will not see any difference. Shorter pipe, richer needle settings.

I was out testing today and found quite a bit more speed with more C.O.B. pitch

in the blades. I had my Nova 28 running mid 80's with great acceleration and top

end punch. I can tell you an OPS 29/40 pipe made that engine sing RPM like never

before. I tested:ABC S-15's,1914,2014,2114, and 1452's all day long with a whole

lot of different pitches and cups. When the day was over I can tell you the S-15,

2014 and 2114 were all in the mid 80's on my Stalker radar gun. I should probably

run some oval times soon, just to see what the newest 21 boat will do.

An Awesome Day Of Testing At The Lake Today,

Mark Sholund

Props-4-U

 

[Chris Wood]

we did some testing today that was very interesting.. there is multiple ways to unload the motor with props.. i have one that winds up like a sewing machine.. but it makes the boat terrible loose.. why.. it takes all the lift out.

we tested a pipe today that is showing to be the real deal.. ask wallster.

mike,, i am going to try and do the prop class this winter.. we can discuss what you got and try to get you going in the right direction.

one thing i have learned over the yrs is you can take something that runs really fast on one.. put it on another and it is JUNK!!

terry said he would like a 4.0 1450.. i put one on mine today it was a turd. i put a 3.6 it was much better.. but them numbers are only 1/2 of it.. blade area and shape play a TON into the prop.

the best guy to discuss this with is chris grimm. maybe he will chime in on this.

chris

 

[shoboat]

Chris,

You may need to adjust your sponson angles for the faster set up.

You will find the boat will go through the turns much better with

less angle of attack on the faster set up. I had a few GREAT SET UPS

today that were almost unbelievable. Water and air were good as usual

here for the day of testing.

Thanks for Reading,

Mark Sholund

 

[Mike Larson]

All right!.... Learning and thinking and testing results, are what keeps me in it..... thanks guys....

Chris, the prop class would be awesome, as, stated in my post I have a box of berylium junk, that, I'd surely like to convert to use....

My approach to testing varies from the norm i'd think as, I'm not into changes and tweaks as infinite as most...

Ignorance, and/or laziness.... I have my hull SET.... have a board that i keep it SET...... the setup, has the boat heat racing ok, stable and little/none quirks in the turns or otherwise..... IMO... if its good keep it there?...

My pipe... starts out the SAME measurement, assembled each saturday before test day... granted, i'll jump to a longer pipe when I pull out the big iron.... ie: test platform normal boat, running well, piping up, doing good....

Then, I go to changing props and looking for gain.... which wherein the problems and the solutions need to be addressed....

I've pulled 3.8's and a 4.0 a few times.... speed gain was noticeable, but the boat launched on the edge, and struggled into the turns...... on plane... great guns.....

Hence the theory: lengthen the pipe, to pull the big iron, right?... What about reducing the diameter of the thing a little?.... maybe a little more tongue off?.....

Of course, I leave myself at the negative end because I balk at moving a strut, or changing boat attitude, stuck, because, going back to the basic 3.4, and the boat set as it was allows me the freedom to at least run it?.....( heat race, and finish)

Puking launches, and two red hot runs all day on a test session make me feel a fool at the lake... with the question of... if my particular test platform is consistent with the 3280 @ 7 5/8ths, and the 3.4, would you, do you, keeping all else the same, cup and pitch your box of junk ranging around this 3.4 mark, and see which one gives gain....

Make the range in diameter change?... or have the cup ranges different, and commence to look at which ones puke and which ones go?...

I only have maybe a dozen 21 hydro props, and i guess the overall goal would be in the most part to narrow down/eliminate the junk, and fine tune/optimize on a given known setup that works, and gain from there......

I only have a coupla pipes.... tested on the same hull for seasons..... while it's OK.... and i'll feel comfortable with the basic test platform at any race, getting a little more competitive, ie: watching Chris and Ron lap me again this year is something I can work for and solve, lets do it...... lotta time on my hands..... thanks for answers, as, as much as I hate beryllium dust, i'm going to have to work on some props.....

PS:... Mark!.... the 50x69 @ 3.4 you did for me 9 years ago ( lol) happens to be the test constant residing on this particular hull.... I'm currently working around this prop.... Nice work then, and it's still nice.... thanks, man.....

thanks to all the respondants.... big time.... lets learn.... ... thanks.... Mike

 

[Chris Wood]

mike,

you are right for leaving the boat where you feel it works ok for you.

this is how i do it.

i set the boat up for whatever. I test ALL my props.. i find 2 that work the best on that set up. then i go back and change the boat.. try again..

then i get the next 2 best props.. change the boat.. and so on.

alot of times you have to change the boat to make the prop happy and visa versa.. some props do certain things.

my suggestion is to work with the props.. once you feel like you have hit the wall so to speak.. then change the boat.

or if you feel you need to change the boat to make that prop work better.. go for it. Me and wally ran sunday.. I ran at least 12 or more props.. revisited some old one's that i thought i would never use again. come to find out they seam to work on my current set up.. need to refine some stuff but it gave me an idea on what direction to go from there.

bottom line.. you have to be willing to play with set up on the boat.. don't be scared to change something.. but before you DO.. TAKE NOTES on where the boat was.. that way if it don't work, you can go back.

i know you stated that your motor is on the weak side.. well if that is the case you won't be able to run a prop that may be faster. you may have to look at freshing up the motor.. and that pipe lenght is a little on the short side for me..

chris

 

[shoboat]

Guys,

There are many ways to go faster, you just need to decide which way is for you?

RPM and C.O.B. pitch is going to make you faster for sure. I think the pipe and

what length you run has everything to do with your end result. You need to make

great power and good RPM in order to pull enough propeller to go faster. You can

run longer pipe settings and try to pull bigger propellers or you can reduce the

propellers and go for more RPM. If you keep the same pipe and length you will not

vary your speed much at all. I can tell you I have tried quite a few different set

ups over the 20 years in the hobby and I still think the best way to go faster is

to try and get maximum RPM out of your motor and pull as much pitch as you can.

The pitch is the fun part, you need to reduce the blade area ratio to aprox. 30%

so you can get the RPM that you need to go fast. Another way with Hydros is to run

your leading edge pitch and cup closer together. Remember .010" of change on the

trailing edge can reduce your RPM by 500 RPM. Recently we have increased the Center

Of Blade Pitch and reduced the cup and we have improved our speed and the ability to

launch and throttle more consistantly. Boat set up is another big topic to consider

also. If you run more angle in your front sponsons it is going to run lighter on the

water and use less HP to go faster. You have to learn to adjust the strut to compensate

for the more angle of attack on the front sponsons or use more lift in your propellers,

which is exactly what we do with our S.A.W. set ups. This is just a start of some things

to think about before you go run your boat next time. I usually just take 24 propellers

to the lake and keep working with the ones that show the most potential.

Have Fun Testing,

Mark Sholund

 

[Andy Brown]

All right!.... Learning and thinking and testing results, are what keeps me in it..... thanks guys....

Chris, the prop class would be awesome, as, stated in my post I have a box of berylium junk, that, I'd surely like to convert to use....

My approach to testing varies from the norm i'd think as, I'm not into changes and tweaks as infinite as most...

Ignorance, and/or laziness.... I have my hull SET.... have a board that i keep it SET...... the setup, has the boat heat racing ok, stable and little/none quirks in the turns or otherwise..... IMO... if its good keep it there?...

My pipe... starts out the SAME measurement, assembled each saturday before test day... granted, i'll jump to a longer pipe when I pull out the big iron.... ie: test platform normal boat, running well, piping up, doing good....

Then, I go to changing props and looking for gain.... which wherein the problems and the solutions need to be addressed....

I've pulled 3.8's and a 4.0 a few times.... speed gain was noticeable, but the boat launched on the edge, and struggled into the turns...... on plane... great guns.....

Hence the theory: lengthen the pipe, to pull the big iron, right?... What about reducing the diameter of the thing a little?.... maybe a little more tongue off?.....

Of course, I leave myself at the negative end because I balk at moving a strut, or changing boat attitude, stuck, because, going back to the basic 3.4, and the boat set as it was allows me the freedom to at least run it?.....( heat race, and finish)

Puking launches, and two red hot runs all day on a test session make me feel a fool at the lake... with the question of... if my particular test platform is consistent with the 3280 @ 7 5/8ths, and the 3.4, would you, do you, keeping all else the same, cup and pitch your box of junk ranging around this 3.4 mark, and see which one gives gain....

Make the range in diameter change?... or have the cup ranges different, and commence to look at which ones puke and which ones go?...

I only have maybe a dozen 21 hydro props, and i guess the overall goal would be in the most part to narrow down/eliminate the junk, and fine tune/optimize on a given known setup that works, and gain from there......

I only have a coupla pipes.... tested on the same hull for seasons..... while it's OK.... and i'll feel comfortable with the basic test platform at any race, getting a little more competitive, ie: watching Chris and Ron lap me again this year is something I can work for and solve, lets do it...... lotta time on my hands..... thanks for answers, as, as much as I hate beryllium dust, i'm going to have to work on some props.....

PS:... Mark!.... the 50x69 @ 3.4 you did for me 9 years ago ( lol) happens to be the test constant residing on this particular hull.... I'm currently working around this prop.... Nice work then, and it's still nice.... thanks, man.....

thanks to all the respondants.... big time.... lets learn.... ... thanks.... Mike

Mike,

You have consistant 50X69 3.4" Horsepower. When the air is good you can pull more....when the air is bad you'll need less. So to pull more prop consistantly you need more power and/or a lighter, cleaner running boat. If you don't improve one or both of those two items you can not go consistantly faster. Yes, there may be a prop that is consistantly a little faster, but it won't be much considering that you have tested with a fairly wide range of props.

So, in conclusion, for next season don't go out and burn alot of fuel testing more props, but rather try to learn this Winter what will give you more power and/or less hull drag. Once you improve those areas than you can go back to testing props again. It's always full circle like that!

 

[Mike Larson]

Thanks guys... Chris.... what pipe, what measurement, feel free to share man... lol.... maybe santa....

andy, i may have the lighter drag hull scenario solved for the spring, for sure, which was the intent of the post, as, testing is over here, and I plan on a re-engineering all the little beryllium turds through the winter.... come out and test on a new build, and be in the ballpark... ie: good, better, best, shazam!.....

I could possibly gain in the power range too, as I run still, a little milder nitro than most do, comfortable with performance vs reliability.....

Basically, and this while not an oddity, from the first ninja I had, to a current hummingbird, and a blackbird, when you ask a designer/manufacturer/owner.... everyone's answer from 10 years ago, and current is "a 1450, 46mm, cupped around 3.2 to 6".... with this in mind, I've a bunch at 3.2, ( slow)... some @ 3.7 to 4, ( quick), but the motor's workin for it, and so on....

How far, to achieve a semblance of pinnacle for the boat?.... Cup the 3 2's up, in a range, and test?.. have a reduction in diameter looking for a little better top end?, range that too, say 46 to 44?.... Uncup (!) the huge pair of 4.0's I have to bring them into better phase?..... If working/having around a 3.4 boat is my optimum constant, it makes sense i'd guess, as, to take what I have around that constant.....

I've a prop box, as everyone has.... thing is,looking at it, at the test pond, knowing that 7 of the 11 hydro props I have dont really perform, and I have the ability to make them at least an option, searching for THE ONE is where it's at..... I think I can do the work, I get to compete with the best of the best around here..... maybe making a little better showing on the water is the goal, but, just testing and burning nitro gets redundant, to me, is wasting time.... I look to gain each time out.... pinnacle? maybe... prop work, possibly..... engage brain, a must.... thanks for your input, guys, i'm gonna narrow the margin............ Mike

 

[Marty Davis]

Thanks guys... Chris.... what pipe, what measurement, feel free to share man... lol.... maybe santa....

andy, i may have the lighter drag hull scenario solved for the spring, for sure, which was the intent of the post, as, testing is over here, and I plan on a re-engineering all the little beryllium turds through the winter.... come out and test on a new build, and be in the ballpark... ie: good, better, best, shazam!.....

I could possibly gain in the power range too, as I run still, a little milder nitro than most do, comfortable with performance vs reliability.....

Basically, and this while not an oddity, from the first ninja I had, to a current hummingbird, and a blackbird, when you ask a designer/manufacturer/owner.... everyone's answer from 10 years ago, and current is "a 1450, 46mm, cupped around 3.2 to 6".... with this in mind, I've a bunch at 3.2, ( slow)... some @ 3.7 to 4, ( quick), but the motor's workin for it, and so on....

How far, to achieve a semblance of pinnacle for the boat?.... Cup the 3 2's up, in a range, and test?.. have a reduction in diameter looking for a little better top end?, range that too, say 46 to 44?.... Uncup (!) the huge pair of 4.0's I have to bring them into better phase?..... If working/having around a 3.4 boat is my optimum constant, it makes sense i'd guess, as, to take what I have around that constant.....

I've a prop box, as everyone has.... thing is,looking at it, at the test pond, knowing that 7 of the 11 hydro props I have dont really perform, and I have the ability to make them at least an option, searching for THE ONE is where it's at..... I think I can do the work, I get to compete with the best of the best around here..... maybe making a little better showing on the water is the goal, but, just testing and burning nitro gets redundant, to me, is wasting time.... I look to gain each time out.... pinnacle? maybe... prop work, possibly..... engage brain, a must.... thanks for your input, guys, i'm gonna narrow the margin............ Mike

Mike:

You said that you were running lower nitro to keep reliability up on your engines.

Consider this: You run 50% and run with a crisp needle to get all the performance out of your engine.

OR

You run 65-70% and run a little richer needle, also to get all the performance out of your engine. Which fuel is delivering more lubrication to your engine? YES, the higher nitro mix set a little richer.

Your easiest performance gain is in higher nitro fuel if you are running around 50%. The small engines LOVE nitro and will perform much better.

Marty Davis

 

[Andy Brown]

Thanks guys... Chris.... what pipe, what measurement, feel free to share man... lol.... maybe santa....

andy, i may have the lighter drag hull scenario solved for the spring, for sure, which was the intent of the post, as, testing is over here, and I plan on a re-engineering all the little beryllium turds through the winter.... come out and test on a new build, and be in the ballpark... ie: good, better, best, shazam!.....

I could possibly gain in the power range too, as I run still, a little milder nitro than most do, comfortable with performance vs reliability.....

Basically, and this while not an oddity, from the first ninja I had, to a current hummingbird, and a blackbird, when you ask a designer/manufacturer/owner.... everyone's answer from 10 years ago, and current is "a 1450, 46mm, cupped around 3.2 to 6".... with this in mind, I've a bunch at 3.2, ( slow)... some @ 3.7 to 4, ( quick), but the motor's workin for it, and so on....

How far, to achieve a semblance of pinnacle for the boat?.... Cup the 3 2's up, in a range, and test?.. have a reduction in diameter looking for a little better top end?, range that too, say 46 to 44?.... Uncup (!) the huge pair of 4.0's I have to bring them into better phase?..... If working/having around a 3.4 boat is my optimum constant, it makes sense i'd guess, as, to take what I have around that constant.....

I've a prop box, as everyone has.... thing is,looking at it, at the test pond, knowing that 7 of the 11 hydro props I have dont really perform, and I have the ability to make them at least an option, searching for THE ONE is where it's at..... I think I can do the work, I get to compete with the best of the best around here..... maybe making a little better showing on the water is the goal, but, just testing and burning nitro gets redundant, to me, is wasting time.... I look to gain each time out.... pinnacle? maybe... prop work, possibly..... engage brain, a must.... thanks for your input, guys, i'm gonna narrow the margin............ Mike

Mike:

You said that you were running lower nitro to keep reliability up on your engines.

Consider this: You run 50% and run with a crisp needle to get all the performance out of your engine.

OR

You run 65-70% and run a little richer needle, also to get all the performance out of your engine. Which fuel is delivering more lubrication to your engine? YES, the higher nitro mix set a little richer.

Your easiest performance gain is in higher nitro fuel if you are running around 50%. The small engines LOVE nitro and will perform much better.

Marty Davis

Dang Marty!!....You weren't suppose to tell Mike the easy way to go faster!

But then again... when Mike's been running fast all Summer on 70% and then has Fall race

with a 45 degree morning and his boat dies just out of reach on the launch of his first heat...then what? hehehe And yes more nitro carries more lube considering equal amounts of oil in the fuel....however the extra lube does not protect bearings from the BIG BANG that the 70% supplies over the 50%.

Just some things to think about!

 

[LarryConrad]

Thanks guys... Chris.... what pipe, what measurement, feel free to share man... lol.... maybe santa....

andy, i may have the lighter drag hull scenario solved for the spring, for sure, which was the intent of the post, as, testing is over here, and I plan on a re-engineering all the little beryllium turds through the winter.... come out and test on a new build, and be in the ballpark... ie: good, better, best, shazam!.....

I could possibly gain in the power range too, as I run still, a little milder nitro than most do, comfortable with performance vs reliability.....

Basically, and this while not an oddity, from the first ninja I had, to a current hummingbird, and a blackbird, when you ask a designer/manufacturer/owner.... everyone's answer from 10 years ago, and current is "a 1450, 46mm, cupped around 3.2 to 6".... with this in mind, I've a bunch at 3.2, ( slow)... some @ 3.7 to 4, ( quick), but the motor's workin for it, and so on....

How far, to achieve a semblance of pinnacle for the boat?.... Cup the 3 2's up, in a range, and test?.. have a reduction in diameter looking for a little better top end?, range that too, say 46 to 44?.... Uncup (!) the huge pair of 4.0's I have to bring them into better phase?..... If working/having around a 3.4 boat is my optimum constant, it makes sense i'd guess, as, to take what I have around that constant.....

I've a prop box, as everyone has.... thing is,looking at it, at the test pond, knowing that 7 of the 11 hydro props I have dont really perform, and I have the ability to make them at least an option, searching for THE ONE is where it's at..... I think I can do the work, I get to compete with the best of the best around here..... maybe making a little better showing on the water is the goal, but, just testing and burning nitro gets redundant, to me, is wasting time.... I look to gain each time out.... pinnacle? maybe... prop work, possibly..... engage brain, a must.... thanks for your input, guys, i'm gonna narrow the margin............ Mike

Mike:

You said that you were running lower nitro to keep reliability up on your engines.

Consider this: You run 50% and run with a crisp needle to get all the performance out of your engine.

OR

You run 65-70% and run a little richer needle, also to get all the performance out of your engine. Which fuel is delivering more lubrication to your engine? YES, the higher nitro mix set a little richer.

Your easiest performance gain is in higher nitro fuel if you are running around 50%. The small engines LOVE nitro and will perform much better.

Marty Davis

Dang Marty!!....You weren't suppose to tell Mike the easy way to go faster!

But then again... when Mike's been running fast all Summer on 70% and then has Fall race

with a 45 degree morning and his boat dies just out of reach on the launch of his first heat...then what? hehehe

And yes more nitro carries more lube considering equal amounts of oil in the fuel....however the extra lube does not protect bearings from the BIG BANG that the 70% supplies over the 50%.

Just some things to think about!

Mike's setup with his Hummingbird is very competitive as it is, but he is very reluctant to run higher nitro, or a different pipe than his spp. If he would try even a conservative setup with a 3280 and 60% i don't think he would ever look back.

 

[Marty Davis]

Thanks guys... Chris.... what pipe, what measurement, feel free to share man... lol.... maybe santa....

andy, i may have the lighter drag hull scenario solved for the spring, for sure, which was the intent of the post, as, testing is over here, and I plan on a re-engineering all the little beryllium turds through the winter.... come out and test on a new build, and be in the ballpark... ie: good, better, best, shazam!.....

I could possibly gain in the power range too, as I run still, a little milder nitro than most do, comfortable with performance vs reliability.....

Basically, and this while not an oddity, from the first ninja I had, to a current hummingbird, and a blackbird, when you ask a designer/manufacturer/owner.... everyone's answer from 10 years ago, and current is "a 1450, 46mm, cupped around 3.2 to 6".... with this in mind, I've a bunch at 3.2, ( slow)... some @ 3.7 to 4, ( quick), but the motor's workin for it, and so on....

How far, to achieve a semblance of pinnacle for the boat?.... Cup the 3 2's up, in a range, and test?.. have a reduction in diameter looking for a little better top end?, range that too, say 46 to 44?.... Uncup (!) the huge pair of 4.0's I have to bring them into better phase?..... If working/having around a 3.4 boat is my optimum constant, it makes sense i'd guess, as, to take what I have around that constant.....

I've a prop box, as everyone has.... thing is,looking at it, at the test pond, knowing that 7 of the 11 hydro props I have dont really perform, and I have the ability to make them at least an option, searching for THE ONE is where it's at..... I think I can do the work, I get to compete with the best of the best around here..... maybe making a little better showing on the water is the goal, but, just testing and burning nitro gets redundant, to me, is wasting time.... I look to gain each time out.... pinnacle? maybe... prop work, possibly..... engage brain, a must.... thanks for your input, guys, i'm gonna narrow the margin............ Mike

Mike:

You said that you were running lower nitro to keep reliability up on your engines.

Consider this: You run 50% and run with a crisp needle to get all the performance out of your engine.

OR

You run 65-70% and run a little richer needle, also to get all the performance out of your engine. Which fuel is delivering more lubrication to your engine? YES, the higher nitro mix set a little richer.

Your easiest performance gain is in higher nitro fuel if you are running around 50%. The small engines LOVE nitro and will perform much better.

Marty Davis

Dang Marty!!....You weren't suppose to tell Mike the easy way to go faster!

But then again... when Mike's been running fast all Summer on 70% and then has Fall race

with a 45 degree morning and his boat dies just out of reach on the launch of his first heat...then what? hehehe And yes more nitro carries more lube considering equal amounts of oil in the fuel....however the extra lube does not protect bearings from the BIG BANG that the 70% supplies over the 50%.

Just some things to think about!

Andy:

Seems like a good tradeoff to me

I replace my engine bearings twice a year so this is not a concern to me.

A little detonation on a .21 is more of a challenge though.

 

[Andy Brown]

Thanks guys... Chris.... what pipe, what measurement, feel free to share man... lol.... maybe santa....

andy, i may have the lighter drag hull scenario solved for the spring, for sure, which was the intent of the post, as, testing is over here, and I plan on a re-engineering all the little beryllium turds through the winter.... come out and test on a new build, and be in the ballpark... ie: good, better, best, shazam!.....

I could possibly gain in the power range too, as I run still, a little milder nitro than most do, comfortable with performance vs reliability.....

Basically, and this while not an oddity, from the first ninja I had, to a current hummingbird, and a blackbird, when you ask a designer/manufacturer/owner.... everyone's answer from 10 years ago, and current is "a 1450, 46mm, cupped around 3.2 to 6".... with this in mind, I've a bunch at 3.2, ( slow)... some @ 3.7 to 4, ( quick), but the motor's workin for it, and so on....

How far, to achieve a semblance of pinnacle for the boat?.... Cup the 3 2's up, in a range, and test?.. have a reduction in diameter looking for a little better top end?, range that too, say 46 to 44?.... Uncup (!) the huge pair of 4.0's I have to bring them into better phase?..... If working/having around a 3.4 boat is my optimum constant, it makes sense i'd guess, as, to take what I have around that constant.....

I've a prop box, as everyone has.... thing is,looking at it, at the test pond, knowing that 7 of the 11 hydro props I have dont really perform, and I have the ability to make them at least an option, searching for THE ONE is where it's at..... I think I can do the work, I get to compete with the best of the best around here..... maybe making a little better showing on the water is the goal, but, just testing and burning nitro gets redundant, to me, is wasting time.... I look to gain each time out.... pinnacle? maybe... prop work, possibly..... engage brain, a must.... thanks for your input, guys, i'm gonna narrow the margin............ Mike

Mike:

You said that you were running lower nitro to keep reliability up on your engines.

Consider this: You run 50% and run with a crisp needle to get all the performance out of your engine.

OR

You run 65-70% and run a little richer needle, also to get all the performance out of your engine. Which fuel is delivering more lubrication to your engine? YES, the higher nitro mix set a little richer.

Your easiest performance gain is in higher nitro fuel if you are running around 50%. The small engines LOVE nitro and will perform much better.

Marty Davis

Dang Marty!!....You weren't suppose to tell Mike the easy way to go faster!

But then again... when Mike's been running fast all Summer on 70% and then has Fall race

with a 45 degree morning and his boat dies just out of reach on the launch of his first heat...then what? hehehe And yes more nitro carries more lube considering equal amounts of oil in the fuel....however the extra lube does not protect bearings from the BIG BANG that the 70% supplies over the 50%.

Just some things to think about!

Andy:

Seems like a good tradeoff to me

I replace my engine bearings twice a year so this is not a concern to me.

A little detonation on a .21 is more of a challenge though.

Yes me too Marty LOL, but not eveyone wants to make that trade.