Is 40 too much to ask for???

[tiqueman]

Well, Im spent... I got a X640, as well as a 437/3 and the LHS owner let me borrow a V937/3 he had S&B lying in the back. I spent a hours last night sharpening and balancing thinking in the back of my mind that the 640 was going to be the ticket. Nope, I was wrong. I tried the 640 first, adjusting the strut at each lap and turned a best 38.7mph. I went to the 437/3, adjusted it till the batts died, recharged and adjusted some more. I didnt reset the gps (probably should have), but non the less, it did not exceed the previous max speed of 38.7. I then wanted to see how the V lifting prop would do. Ha, it was nuts. The boat, once it got on plane and hooked up (about 30 feet) it was hopping all over the darn place, pushing itself completely out of the water. Couldnt hold full throttle as it would have turned over. With the batts getting close to the cut off voltage, I changed back to the 442 and ran a 39.1. Recharged again, adjusted the strut back to where I ran the 40.2 and decided set it this time about 1/32 deeper. I threw it in the water and ran a 40.5. I reset the gps and ran a 40.4. Lil more each time... I think the 442 is where its at. I may try a 440/3? But probably not for a bit. I gotta slow down on my expenditures while not working

I left it at that setting, taped the lid back down and ran the hell out of it for 4 minutes or so. I let off the throttle once because a duck thought the boat wasnt coming that fast. Other than that, I was at least 95% throttle the entire run. I brought it in, pulled the hatch and SMOKE! Then I realized, the wire motors were against the flotation on the lid and melted the foam. The motor was at 126F (exposed can next to cooling jacket), batts at 144F and ESC 123F on the caps and 122F on the anodized aluminum. I think maybe higher C rating batteries may be in need???

[domwilson]

You're running the Turnigy 5000 mah 20C's right? The higher "C" will give more available current, but might not help with the temps on the motor/ESC. As saving money is priority, I would continue with strut adjustments and COG. Also shorten the run time to 3 mins. Each time. Give things a chance to cool down. Maybe a little scuff to the bottom of he sponsons. Ya know, try all the things that are "free" first. Read up on prop mods that you can do. These might help.

http://rcprops.com/TechNotes/rcprop_tech_info.htm

http://www.rcboat.com/prop.htm

[tiqueman]

You're running the Turnigy 5000 mah 20C's right? The higher "C" will give more available current, but might not help with the temps on the motor/ESC. As saving money is priority, I would continue with strut adjustments and COG. Also shorten the run time to 3 mins. Each time. Give things a chance to cool down. Maybe a little scuff to the bottom of he sponsons. Ya know, try all the things that are "free" first. Read up on prop mods that you can do. These might help.

http://rcprops.com/TechNotes/rcprop_tech_info.htm

http://www.rcboat.com/prop.htm

Im running the Reedy 5000 mah 20 C's. But basically yes, all the specs are the same. I had been doing so many 30 second and one minute runs, I figured Id dog on it to see how things went. Other than the batts being in the 140s, everything else was in opperable temps wernt they? Thats funny you mentioned scuffing the hull. I thought about that this am. Ive always shyed away from learning prop mods. Maybe now is the time....

Overall Im quite happy though. I wanted 40 so bad and I got it. I was hoping again to get some vids today but it didnt happen. I will try and get some soon. The hulls ride attitude is beautiful. To think where this hull started, to where it is now, makes me VERY happy.

Thank you everyone who got me to where I am... and will continue to help make it even better. I will keep you posted if I do anything amazing.

[domwilson]

Not too bad on the temps. The best way to show your appreciation is to share what you've experienced and learned with others. Keep tuning. I hear a solid 45+ mph coming on...

[tiqueman]

#1 tip: Have more than 1 set of batteries..... Cause right when you think your getting close to figuring something out.... youll find yourself waiting several hours to see if it worked. Its just amazing how the smallest fraction of an inch change can make such a difference, good or bad. And a lot of which I thought would be an improvement, ie adjustments, props etc, I found myself wrong a lot of times. Adjustments and what not that I thought were going to be a negative impact, a lot of times were more positive than I could have imagined. ie, I never would have thought a 442 would be my prop. When I couldnt accomplish what I wanted on a 642 and went to a 442, I would have bet the boat that a 640 was going to be it. Glad I didnt... I wouldnt have anything to do this weekend.....

[domwilson]

Just wait till you figure out modding props. Just as strut adjustments, a little goes along way. Start out a little at a time. I think you'll be happy. Not just in speed, but in what you learn.

[tiqueman]

Just wait till you figure out modding props. Just as strut adjustments, a little goes along way. Start out a little at a time. I think you'll be happy. Not just in speed, but in what you learn.

I went through the links you posted above about prop mods etc. Some of it makes sense... I "de-tongued" a prop once. It was a Prather 270 on one of my gas deep V's. It didnt do what I read it would do. Maybe I did something wrong. It ran the hull a lot more wet. Ever since that, Ive never tried or even considered modding a prop again.

What would be some considerations for modding a prop for this 32" cat hull. The tongue of the prop is used for out of the hole and acceleration correct? Should I consider removing a little bit of the tongue on the x442? One of the links stated this is one of the top mods for the X series props. Im not quite following cupping. I know its the bending of the trailing edge but which way. Kinda hard to explain but, lets say you have the prop mounted on a shaft, on a drive dog and turned it so that the shaft is running verticle (ground to sky). The trailing edges of the prop are facing skyward. Is cupping bending it so the tips are more skyward? Because in my mind, if you bent them as in twisting the trailing edge towards the leading edge, now your changing pitch.. right? Ive also never thinned a blade any more than just to balace a prop out after sharpening. I think I may do that first.



Its crazy to me that all the years I ran gas (sport boating) no racing other than with friends, I only time trialed 2 of them in one afternoon of running. Stop watched them between 50' bouys if I remember correctly... might have been 100'. And I was content on how they performed. They were both in the ballpark of where they should be and that was that. As long as they started and ran well...thats all I really cared about. NOW, Im wanting to go back to my gassers and see what I can accomplish. I based all my adjustments I did on them with eye and ear. You could tell if the motor didnt like something you did by how it sounds. And its very easy to tell when a 50"+ boat has a bad ride attitude...

EDIT i just re-read about removing tongue. After re-reading it, it said that removing tonge increases speed AS WELL AS ACCELERATION. Whats the purpose of tongue then? If it doenst help in acceleration and limits your rpm, why does Octura put so much tongue on the x series???

[domwilson]

To me, that X640 or X642 would be the most likely candidates as you are getting your top speed with the X442. But before you start, I would ask Egneg (forum member) a price for him to do it and/or some advice. That way you would have a good jumping off point. He has been recommended by alot of forum members. For me, I started out with a damaged prop (ran to shore). I straightened it and figured I had nothing to lose. Then I detounged it and bent the trailing edges just slightly backwards. Turned out pretty good. But I had nothing to lose by experimenting with that prop. I've done a few more since. But, I do suggest asking Egneg questions before you start.

[domwilson]

Oh, I do reccommend getting some playdoh so that you can compare blades. My first attempt I used paper templates to keep the blades even in size. Too much work. Darin Jordan I believe posted something about this some time ago.

[domwilson]

http://forums.offshoreelectrics.com/...hlight=playdoh

[tiqueman]

Ha, I made some playdough yesterday. It was great at first, but after a coulpe hours it turned into a mash potato like substance. Got all sticky and fell apart. Im going to make silly putty today and try that out.

I played around with the x640 (didnt want to mess up my 442). I ran it only sharpened and balanced first for a reference, peaked fresh batts ran a 38.7. I then went to the bench and removed some material across one of the entire blades until it fell rather quickly to the heavy blade. I then re-sharpened that blade spending a bit more time than usual finishing it w/ 400 grit paper. I then went to the other blade and removed material in the same fasion until it was balanced. I took a little extra time, assuring that I could place the blade at any position and it would remain there. I also spun it several times to be sure it would stop willingly in any position. Once I got it to that point, I went over the entire blade with a soft wire wheel on the dremel to clean things up a bit more. I re-checked balance and all was well. I ran it again on freshly peaked batts and ran a 38.9. .2 MPH faster. Im not sure how much I lightened it or thinned it. Just a little bit though. Nothing drastic. In any event, .2 is .2! Then, back to the bench and I removed a little bit of tongue. Not much at all, I want to take baby steps in doing this. I took off a heavy 1/16". I ran it this am, again on freshly peaked batts and ran 39.0mph. At .1 faster, Im not sure completely if it was the slight detongue or what. Possibly? I dunno.

I did not change anything on the strut during these tests to be sure it was all prop and nothing else.

Heres what the prop looks like now... Should I continue to remove more???

[domwilson]

It could be the angle, but the blade on the right looks like it has more tongue than the blade on the left. Use the playdoh to verify. If it is even, try the strut adjustments.

[tiqueman]

Its the angle. They are exactly the same.

[domwilson]

From the pic, it looks good to me. Is the face of the blades polished?

[tiqueman]

Having a hard time getting a perfect pic... but heres a better one anyway. The right side of the blade it towards the light source (window) so the left side has more shadowing...