Cleaver cutting

[Tyrone Biggums]

I read out here that there is another member out here with an Aquarius with a 50 tldi running a 11X18 hill cleaver so I ended up buying one.
I can only 5100 rpm at neutral trim. I can trim the motor out more and get 5200-5300 but the angle is excessive IMO.
With only being able to go 1" on pitching, cutting diameter obviously is my only option ?
If I were to try to reduce diameter would the proper way be to follow the original radius to point B, all the way to the root or stop around point A and contour it from that point ? Also will this totally mess up the blade geometry and would pitch be affected?
"assuming" it really is an 18 and get it repitched to 17 and remove 1/4" at a time is it feasible to make this prop work ?


The boat is an Aquarius 50 TLDI 15" with prop shaft about 5mm above hijacker centerline - A whopping 43mph was best I could get monkeying around hydraulic trim.
I did raise the motor one hole up and was able to get 5500 with trim jacked out but having the large tldi motor bracket I'm not comfortable with that mass up so high on transom and would rather put it back at the 5 mm setting... Maybe it's just me but I would rather keep the CG low (yes plenty of pisser water coming out).


59873

[zul8tr]

What is the reduction in diameter with that proposed cut line?

What are you shooting for with the performance, more top end, acceleration, etc.?

Don't know about cleavers (Ron Hill needs to chime in here) but I have trimmed the non cleaver 2 and 3 type blades (for hydro) like you are proposing from A to B. Your cut design will increase rpm but will loose blade area but with all prop mods testing is the only truth. Average prop pitch will not be significantly affected with the cut line you propose.

If you do the cut ONLY blend grind the non push side (facing forward) to get the new sharp edge to be same as the original. You will have to rebalance the blade. To help that once you cut the first blade make a pattern to mark the other blades to be cut to keep same shape and keep near balance. Gram weigh the prop before any cutting. To help with balancing cut one blade and blend grind an weigh note difference from original, repeat with 2nd blade weigh and shoot for same weight difference from 1st blade, etc. You have to be consistent with the grind blend area when doing this.

Then final balance and finish the surface.

[Tyrone Biggums]

I am trying to get some top end out of it and get the rpm's up where they should be and not make a paperweight either.
I made a template of the original blade ear and made the shown proposed cut using that.

It comes out of the hole normally per a cleaver ( minimal throttle fuss) and other than that acceleration is good everywhere else.
The markings I have shown is .250"
I also was wondering about removing some cup and if so, where along the blade should it be cut? Whole length, 70% from blade root?
Once I get the prop close to where it needs to be and knowing I can have an inch de-pitched, it will get sent out to the prop shop for the final cleaning up/balancing. Frank and Jimmy's prop shop is fairly well known down here but they have a crazy 2 week lead time.
If anyone knows of another good shop down in southeast Fl area I would be open to try them.

[zul8tr]

Are you going to cut it and blend grind it?
If so before you depitch it try it the pitch it has may be OK for the engine height you run. I would leave the cup alone at least till after you trim and grind blend it and try it. Removing diameter will free up a prop. What is the existing diameter?

I would cut the blade starting where point B is and make a smooth transition from the remaining curve. Not following your 70% statement.

[Beale Tilton]

Try Jeff Titus in Lake Placid Performance Propellers 863 465 9438

[fs5]

you got to raise the motor right up as high as it will go and still pump water mate. cleavers don't like to run to deep .
if you want the boat to be fast , you got to jack that motor up!
check this site out, plenty of info . most guys just run the carby 50 tohy.
http://www.thundercatinflatable.com.au/forum/forum.php

[fs5]

also i wouldn't cut on the prop just yet . most guy's run from 11 to 12 inch diameter.
i'd get get the prop scanned to see what pitch it is first before cutting on it.

[Tyrone Biggums]

The motor was already 5mm above the highjacker center line which I see most run about level with the cl.
I do understand the more weight the higher you can go and the TLDI is slightly "porky" compared to a carby 50 (30-40 lbs). I did go up the next hole and got 5500 trimmed out but it just feels wrong with the tiller/powerhead so high up- could just be me though.
I raised it to the third hole down and my prop shaft cl is 35mm above the inflation tube cl ... again with the extra weight it may work?? It just seems the clamp bracket is WAY high off the top of the transom even down at 5mm. ( yes it is a 15" mid)
Another question I have and will make a separate post - Are the dimensions/size from a carb or manual trim tldi bracket radically different ?

I agree on having the prop scanned but it is what it is and am stuck with it for now, so if I already get the lower end of the recommended rpms I figure between removing 1" pitch and trimming diameter I could get it a little higher.

I have been to the thundercat site and there is a ton of good stuff there.... seems I am stuck in a league of my own with this TLDI... may be time to start looking for that 70 yammy!

[fs5]

i forgot to ask are you running 1up or 2up ?
1up you should easy get well over 50mph .
if your 2up maybe the 18 is to much pitch .
guys like to run a 16g yam or powertech 16p on stockish motors for topend stuff.the lighter crews can run an 18p.

rolfhat and rwn on here run 50 tohy's on there cats they maybe to help you more.

[Tyrone Biggums]

Normal running compliment is....
126 lbs wife + 3 lbs of breasts lol
me 209 lbs
25-30 lbs adult beverages/ food
and I don't expect to see my highest numbers with all that.

So Friday I lifted the motor one more hole up which came to 35mm above the hijacker cl.
Placed 120lbs ballast ( I didn't have anyone to go with me and Fri PM on the creek there is hardly anyone out there so didn't want to entertain the aspect of a blow over with no one around) and my best speed playing with trim 46.6 mph @ 5970-5980 rpm maybe bounced the rev limiter here and there going down wind which is odd ( ballast was moved aft in middle of floor). Plenty of water pissing also.
Doing the math my slip came out to 17% which I think is a little too much for a cleaver.
Coming out of the hole was not too terrible but I also have a TH marine 5 degree wedge and a 2.5 stacked so I do have some negative trim.

Saturday I removed the 2.5 wedge, slotted the engine bracket between the second and 3rd holes and fabricated a jack plate of sorts to allow me to do changes at the sandbar.
Full running weight as noted above - semi bitch getting out of the hole and I am only seeing 45mph - about the same speed I get with my yammi 15g semi cleaver at lowest engine height which seems to be my good surf prop as it launches out of hole and hits no matter what speed.

[Tyrone Biggums]

59905
I thought about trying to go even higher but as you can see that thing is waay up there and stress to the transom is my concern. Mind you the TLDI has the big motor bracket but the dimension from the "hook" of the clamp should not be different than a manual trim as we measure shaft length from hook to cav plate.
You may notice too that my transom is built up 2" - The person I bought the setup from tried to make a 20' shaft setup and even with that the motor was way low. The powerhead height was just too weird up high for my taste and probably one of the reasons APBA will never allow a 20" to race.
I found a 15" Nissan 40 tldi for $300 and dropped the powerhead on it - talk about night and day in general with handling and feel!
At this point I think it's time to have the prop scanned to see what it really is and go from there, I didn't want to send it out right away without testing as they have a 2 week back log.

[zul8tr]

How much to scan prop + 2 way ship?

I have a relatively easy and inexpensive way to measure pitch along the radius and at any radius on the blade. If interested PM me for my email and for Ho To make the simple device. Certainly not equal to a digital scan to map the entire blade surface but good enough to see where you are at. Been doing this since my APBA hydro race days back in the 1970's for relative comparisons between props.

[Roflhat]

I wouldn't go cutting that prop mate, your TLDI should easily spin 11x18p to the limiter when set up right.
As Jake said you need to raise the motor until you find a sweet spot, test different heights and write down your results

[Fastjeff57]

Was thinking that as well. As the carpenter says: "You can cut it shorter, but you can't cut it longer!"

Jeff