DIY Boat Propeller - Part 10 - Tested at 600 rpm

this is a variable pitch control propeller system  so it's actually made up of two shafts this one   works in and out and both of them spin so what  happens is this inside shaft can move three   inches in and out and as it does this pin has  a block that rides on it and the block slides   in a groove that's in the base of each propeller  so as it moves in and out the propeller changes   this angle of attack or its pitch pitch like  this on a motor boat it would just be spinning   around or feathered it wouldn't be pushing any  water this direction or that direction for our   sailboat this is considered feathered because as  we sail forward water passes by the propeller and   there's not a lot of drag but the cool thing is we  can change this to any desired pitch so we can mix   engine power with sail power in other words we  can be sailing along at four knots put a little   bit of engine power into it pitch the blades  appropriately and pick up another two knots   and we've cast two sets of these propeller blades  this set though i haven't yet ground down i got   a nice sharp edge originally i didn't have a  shroud on the boat but then i added a shroud   and so i've cut these so that they fit just  inside that shroud now this round piece of   metal back here that wraps around where the prop  goes is our shroud some people refer to them as   court nozzles but this really isn't a core nozzle  a cord nozzle would have a an aircraft wing shape   design to it here and it works a lot like an  aircraft wing it helps build a low pressure   here and accelerates the water before it even  gets to the propeller they work great and better   than a shroud but they also have more drag so when  we're just sailing this will be a little bit more   efficient than a quartz nozzle and we might modify  it later on it would be really interesting to see   the contrast between a shroud and a court nozzle  you know given everything else remains the same   inside the boat is where this gadget down here  sits that's our 100 dead variable pitch control   unit drive shaft attaches to this end propeller  shaft comes through the shaft log attaches there   a push pull cable will attach to there and it  changes where that brass fitting down there rides   along and that changes to where oil is either put  on this side or this side of a big piston that's   right there and when that piston moves that inside  shaft there moves and that changes the propeller   and the hydraulic oil that will be supplied to  it will just come off the power steering pump on   the engine so whenever the engine's running  the hydrostat will have oil supplied to it   so the first thing i need to do is put that  shaft in the boat and set this set in there   mark them off and trim them down appropriately  take the seal off i'm going to push out ah cutlass bearing and the next thing to go in is  the cutlass bearing it's just a brass tube with uh   rubber on it it's got grooves in the rubber  and that's where water can go through because   it's water lubricated and the water will  actually flow back through and fill the whole   shaft log yeah it's going to take a little bit  of force but that's okay what the water will do   is it'll flood the whole shaft log but there's a  seal at the other end that stops flooding the boat   fresh coat of paint in there so if it's too tight   i'll have to take it back out  and sand down some of the paint no too much friction so i get to use my  cutlass bearing puller before i ever imagined   i would and one of my neighbors little girls  brought me a cupcake merry christmas to y'all yeah i think was just too much for it gummed it up that's much better there we go yeah okay that's good enough all right  that was pretty easy gracias amigo   no get us a fee here we go it's cold out this  morning christmas day merry christmas everybody   not gonna have to take off much just a little  bit that's a little too close right there   a little shake or a bump in the flange  and it'll strike it i don't want that i've got two sets of these blades those  i know fit so i'm just going to make sure   that these are actually no taller than those be  careful handling them without gloves the edges   here are really sharp well i guess they're all  within a sixteenth of an inch no more than that   now the goal is to get them balanced and and  we've talked a lot about that uh the first step   is just a way of see where we're  starting fourteen thousand and 544 grams so more yeah great so you ready for tacos man  i'm getting hungry over here   i didn't think i'd get ever get  hungry again after yesterday   yeah i pigged out i probably ought to put some  trying to get my propeller system oh there it goes   you know you start cussing at something and it  just all sudden works for you i got my pellet i'm   gonna balance the propeller today yeah some guy  gave me this comment that i should spin it with   a drill and i just thought that was the nuttiest  thing in the world and the more i thought about   it the more i kind of like the idea so i'm gonna  spin the prop with a drill here a little while   that's walking down the  beam oh it's gonna come off the whole propeller shaft and the  prop i gotta figure out a way of   getting it not to walk down the shaft though actually come over half tacos okay okay all right yeah there's a little  bit of wobble here but not much it's starting to wobble that's working fine it's not moving  so this sand starts to rock back and   forth but it hardly has anything on  it i think we shim it a little bit all right i think that's about 100 rpm i  don't know what we're supposed to see is   it supposed to like shake apart more or i  mean because it's sitting on the stand here   and it's not like the most solidly based thing the  only thing i notice is it clicks one blade clicks there you hear it i heard it yeah  so one of them is terribly tight that one there that was loose this is my second  set this is my that was a little loose too your   spares yeah yeah that's the only one that's  really snug they're just not greased but they   have just wd-40 on okay this is this is stable  up here now i don't know that shim underneath it go for yep lunch oh lovely stuff you're going to pack all that  fuel aggression anyway yeah okay all right that was easy yeah oh yeah grease helps a lot my ex-wife  taught me that what use plenty of lube don't you have one of them rpm  thingies i do let me see if i find it   oh it's even got a little laser light you see wow that's 95 already 95 rpm 108 yeah i  bet we had it up to a few hundred last time oh man that is flying now 210 213. yeah there's a bit of a wobble right there if i throw it down a little bit  i can just get wobble out of it   the question is how do we tell  why it's wobbling you know 200 there's no wobble going up i wonder if the wobble  will go out of it at a higher rpm   you think it would get more and  more pronounced the faster it goes   it doesn't look like it's getting any  worse in fact it looks smoother now this back one's got a little more wobble in  it now no i don't think the shaft has been i   think it's just out of balance a little bit it's  wobbling hold on take it on up now remember if   it comes out it's going to hit the dirt  and it's going to fly off that direction   now this definitely has more  wobble on the backside here and i think that's because the stand posts are so well my question is if it was if  we were going to try and balance it   how would we know which blade to add weight  to or take weight off of i mean with we   just i think we just have to experiment but i  don't think that's enough wobble to sneeze at   these things are just sitting on dirt and boards  so they're springy as hell i mean look at that i   can shake it around by just putting five pounds  on it we moved these stands close further apart well there's no weight on this stand back  here hardly at all right it's only most of   the weights on that forward all the  wobble is right back here it's not   up there it kind of started up there  and then it came back this direction so i don't know i think if i took  lead bars and weighted that down more   i'll [ __ ] them on the frames yeah that's  where it was taking it last time wasn't it   you can see a little bit of it  not much dirty there's some wobble maybe this is what it feels like now the bearings are sealed  they're probably all right can't wait it's consistent i mean it  starts rocking and then it stays there   get about 230 to 240 and it's bouncing all right  one's down here this is our second set of blades   this one's out by a hundred grams on weight  so we're going to see what the difference is   try to wiggle man there it goes  yeah that helped a lot okay you ready aren't you well  ready now oh how about now oh no okay ready to rock and roll we  tore the last one apart at 420 rpm   so we'll see if this holds together and this  blade sets a hundred grams difference between   the blades the last one was only 24 grams so  we'll get a very non-scientific measurement   here but we'll see how bad it shakes more or less  i guess this is going to shake more grab the meter oh yeah queens that's really not taking any  more than the last one isn't it 2 30. yeah   that's taking more it is sticking on 235  248 242 it looks like it's smoothed out look at that look how smooth it's  running down 30 50 360 360 80. 430 440 50. 4.90 500. five forty five  fifty five sixty five seventy   five ninety five six hundred that's our max all  right the grill's getting hot i'm coming off slow 6 30. all right there's three right  in the house rotating with six   five eighty five seventy five sixty  that's fantastic still going over 500 i think it has to do with the residence resonance  residence yeah i think it's a residence problem   yeah let's stop it 240. well i don't think 100 grams is a big  deal anymore yeah i feel real good about   that well no i mean i wouldn't do anything  because there's only 123 grain grams right   okay just to give you an idea of how much 124  grams is that's stainless steel stuff 122 grams   124 grams between the three blades i could take  that off right out here on the edge if i wanted to   but i don't know where they're not balanced  that's the other thing is we're not finding   center of gravity and this to me when you  spend it if the weights out here on the end   and all this weight's in here close that's  going to throw it off because this has more   pull force right because it's your weight's  further out yeah yeah yeah the centrifugal   force would mess it up so i don't just need to  get them in the right weight if i was going to   get them better i need to get them with the  center of gravity in the same spot right   that's so smooth that's that's smoother than  the other one was yeah and this is why this is   my first set yeah not my second set you  know i i could i think what we do is we   put it in the boat we mess with it we have a  vibration and then we can take them back off   while we're in the water it's no big deal and  we i don't think it's worth messing with now   i only have one set of these square  little blocks and it's just the kind   of thing you could drop into the drink  when you're changing out a propeller blade   in the mississippi so i'm gonna get  measurements off before it goes in   and draw up some just so i can make some spares  now i'm not great at cat i just have functional   skills but i can draw these pieces up and  then we can machine them out on the cnc and   we even did that to design the prop i started  with mathematical formulas to give us the   degree of offset of these various chords and  then we put a skin over that and that becomes the   pattern that we cast from so if you want to see  videos on the making of these propellers uh i got   a whole series of them and most of the information  is in a great book called uh propeller handbook by   dave ger and a great book for how to calculate  all this stuff it even has a section here on   uh variable pitch control propellers so you  ever want to know anything there's a book on it that may be the final installation  so i'm going to jam it full grease   it goes oh yeah that's a nice sound it  is still bizarre to see it floating yeah   sitting up in the air like that okay that's  it next video we'll hook it up inside the boat   so fortunately it looks like we don't have to do  anything further to balance our blades but if we   did or if we find that it's got too much vibration  on the water there's some things that we can do   and one of them is to suspend the blade like this  with a clamp but we'd want to put a real sharp   point on the clamp on this side and this side and  that would give the blade the ability to find its   balance on those points then we get a spirit  level and we put a line straight down the blade   that's perfectly vertical it's orientation and  weight this direction then we unclamp the blade change its orientation about 90 degrees out  and we draw another line straight down the   blade vertically where those two lines cross  that's center of gravity and what we'd be after   is we'd want to get the center of gravity for  each blade in the same spot and so by taking   some measurements we could see okay this center  of gravity is much higher up than this center of   gravity so if we take some weight off the bottom  of this blade that center gravity will move up and   if we got them all matched perfectly they'd be  much better balanced so it's not just a matter   of their overall weight it's also a matter of  where that weight is actually located on the blade   and as we saw in the cad drawings each of these  blades is made up of a series of airfoils that   skinned over and if those air foils are a little  different between one blade and the next then   the performance of the blade might be a little  different it could be pulling a little harder or a   little less so that could cause a balance problem  it's not likely because they're all good castings   from the same pattern but it could be an issue and  if it comes down to that we can put it over on the   cnc machine and have it probe the whole surface of  this and get a mathematical plotting of this blade   do the next blade compare the two sets numbers  it'll tell you where this blades foil is a little   bit different than this blade then you find  the heavier of the two blades and you grind   it down a little bit until they're perfect  in truth i've seen propeller blades that were   plates of steel welded onto solid steel shafts  and they were working okay so you don't have   to have everything down to spacex technology a  lot of the in between stages will work just fine   so that's it the blades on what did you make  today send us your photos and remember our travel   to the port date is august 12th and our launch  date is august 21st come join us for a tragedy say but i will show all of you   the past is what i know the  future is where i'll show yes say goodbye to what i used to know how fast  time will come and go but i will show all of you the best is what i know the future is you

Channel: SV Seeker

Views: 1,202,008

Keywords: Sailboat, Welding, Metal Fabrication, Boat Building, Plasma Cutting, MIG, Sailing

Id: b15Z90hcfYI

Length: 24min 54sec (1494 seconds)

Published: Thu Jan 07 2021