Differences between high end ESC's and cheap ones for Lehner motors?

[TRUCKPULL]

I’ve also noticed that when setting the hull on an even table surface —some of the steps don’t exactly match the opposite side in height. Primarily the 2nd step before the last on one side which causes the last step (before drives) on one opposite side to have like 4-5mm of air while other one is perfectly touches the surface. I doubt that helps given how sensitive these hulls are after all. I’ll need to sand it down and see if it helps at all...

Sounds like you need to blueprint the bottom of that hull, to be out 4-5mm is way to much.

Larry

[RaceMechaniX]

The scale cats are notorious for the low speed transition wobble. Most people point and squeeze to get up on plane quickly. These seems to work better than slowly motoring up.

[srislash]

The scale cats are notorious for the low speed transition wobble. Most people point and squeeze to get up on plane quickly. These seems to work better than slowly motoring up.

That’s what I figured Tyler. I just need to get to another lake instead of the close test lake with all the waterski markers in it. Lol

[srislash]

Yea that’s the one. Well then, I’m glad it might not be a symptom of the castle edge/ice throttles differences. Could it be that there is too much lift being created on the rear near props? I think I’ll play around with the drive angles and CoG a bit. Perhaps there’s not enough prop in water...

I’ve also noticed that when setting the hull on an even table surface —some of the steps don’t exactly match the opposite side in height. Primarily the 2nd step before the last on one side which causes the last step (before drives) on one opposite side to have like 4-5mm of air while other one is perfectly touches the surface. I doubt that helps given how sensitive these hulls are after all. I’ll need to sand it down and see if it helps at all...

Btw, have you tried playing around with the angle of rudder blade? What angle is yours set at currently

If I remember correctly, Don’t all of the SF300 lite versions have data logging capability?

I got these from Keith with no logging. The only thing I’ve played with so far was CG. Moved it back some and spun it out and flipped it. Hoping next weekend to get it out again. Way too much on the plate this weekend.

[srislash]

In my case anyway I doubt if it is a prop lift issue. I’m only starting off with 447’s. My Daytona hull does this too. And curious about the ride surfaces, my pal up here had a 99 and never could get it going good. I’ll try to check mine at some point over the weekend.

[dmitry100]

It's strange that i have never really seen that wobble in any of the SAW videos of small or big cats ... but perhaps they all are starting off fast to begin with.

i think that the fact the HPR99 is soo thin in terms of width and tall compared to every other cat of it's length -- the wobble is probably that much more obvious in this particular hull

[srislash]

It's strange that i have never really seen that wobble in any of the SAW videos of small or big cats ... but perhaps they all are starting off fast to begin with.

i think that the fact the HPR99 is soo thin in terms of width and tall compared to every other cat of it's length -- the wobble is probably that much more obvious in this particular hull

I tend to agree with you Dmitry, that same friend aforementioned also has a MHZ 185 that does it somewhat too. Just the hull, they are good once at speed just takes some driving skills. Here is a pic of the last step and the rudder for you

C4AAB39A-EBBA-4418-8616-EA0B30A71F80.jpg

[dmitry100]

Is it an Aluminum or stainless steel rudder?

Looks good either way. I’m using the previous version of the rudders that Werner would make... they bend so darn easy. I could probably fold one up with one hand lol. Not sure if it’s intentional or not but at $15 per blade it will get expensive lol. So I want to find someone who makes a sturdier steel version of the blade

[srislash]

It is aluminum rudder Dmitry. It is from Kent (natatorun) Customcfparts.com

He dare me to break/bend it. Haha. Another option would be a custom knife builder. There is a guy near me that I keep saying I’m going to stop at.

[dmitry100]

must be made from a stronger type of aluminum than mine then

any ideas how much is he selling replacement blades for?

[dmitry100]

Tyler, is there such as a thing as too much gear oil (amount) or too thick of a gear oil? I'm using some 75W-140 Full Synth gear oil but I feel it might be a little too thick of a consistency. The stuff sticking on the flex cable once taken out after a run is almost a grease like consistency. Though, the good thing so far is that even without any load this stuff has completely quieted any rattles, noise, or vibration in the drive line...

Figured it might help if there was any water, but drive line is sealed well anyway

[RaceMechaniX]

Yes there is. 75W-140 is too thick. I would try chainsaw bar oil if you prefer oil or use some Klotz 2-cycle engine oil. For most flex cables running in brass stuffing tubes I stick use grease especially for heat racing boats. Apply the grease and work it into the valleys betweens strands. Squeegee off the excess grease. It's important to not over grease the cable. A little grease is all that is needed. If you are running flex cables in Teflon lined stuffing tubes try the chainsaw bar oil or some ATF. Again just apply enough oil to coat the cable and wipe off excess.

[srislash]

must be made from a stronger type of aluminum than mine then

any ideas how much is he selling replacement blades for?

I have no idea on the rudder blades Dmitry, but the complete with hydraulics was $200.

[dmitry100]

Man, these LMT 1950 motors pull some crazy power especially for being so small ...

Ran the hpr99 on 6s yesterday with only a 1715 (42mm) and my external sensor showed a max current of 401 amps and 8,400 Watts before violently crashing...





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[dmitry100]

Tyler, something like this would work? https://www.amazon.com/Klotz-KL-100-.../dp/B001BHI5J4



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[RaceMechaniX]

Yes. If you are running Teflon liners and want max speed try ATF. You will have to re-oil every third run though. Klotz will last longer, but has more drag.

[srislash]

Man, these LMT 1950 motors pull some crazy power especially for being so small ...

Ran the hpr99 on 6s yesterday with only a 1715 (42mm) and my external sensor showed a max current of 401 amps and 8,400 Watts before violently crashing...





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Holy *!***!***!***!** Dmitry, you do need something stronger in the rudder department.

[dmitry100]

Yea tell me about it. These rudders must not be intended for anything heavy duty... they bend like soda cans. I’ll see if Manuel wenny or nata2run has something better of the same size

Gonna try my ABC 1717 cut 42mm props...
Could only imagine how much more amps it will pull. Though this is only burst current which probably doesn’t mean much yet

[dmitry100]

If you’re in need of some logging you should try the Unilog 2 ... it’s very featureful and has lots of support/comparability amongst all transmitters as well (For live telemetry like for spectrum xbus)... It’s reasonably priced compared to others I think. You can even buy any P1000 temp sensors for like a dollar or 2 from eBay to save $ instead of the $10 or 15 each they sell. They have 400 amp current sensor which I’ve seen others use to go over 600a

Don’t you have the eagle tree telemetry tho?



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[srislash]

If you’re in need of some logging you should try the Unilog 2 ... it’s very featureful and has lots of support/comparability amongst all transmitters as well (For live telemetry like for spectrum xbus)... It’s reasonably priced compared to others I think. You can even buy any P1000 temp sensors for like a dollar or 2 from eBay to save $ instead of the $10 or 15 each they sell. They have 400 amp current sensor which I’ve seen others use to go over 600a

Don’t you have the eagle tree telemetry tho?



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Yes EagleTree. I’m trying the magnetic ring amp pickup this time. Says it’ll read 300.

[srislash]

Dmitry what Kv are those little suckers?

[dmitry100]

2508kv ... so about 73k unloaded. From what I can tell about 59k loaded before it flew out of the water

[srislash]

Man that makes a nice readout on that UniLog.

[dmitry100]

Yea plus it’s already compatible with major TX/Rx, so I’m thinking to pull the trigger on a Frsky qx7 or x9d stick transmitter. For the live telemetry from Unilog with 1.5km range and 9ms response time... which is great compared to everything out there at that price range. Plus the Frsky receivers are $20 each. It’d be nice to have some amp and temp readings for a change before/after a SAW pass. Plus I’ll be able to use it for drone racing if need be lol


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[dmitry100]

Tyler, you think this kind of a wedge blade would work for a SAW rudder? Versus the stock one ... I’m replacing it due to the bending issues I have... seems like super weak aluminum.

Its certainly a thinner wedge by a good bit and really sharp(er). But just worried it might affect handling

[RaceMechaniX]

That will work, but not that great. You want a pure wedge, having the flat section on the back half of the blade does nothing.

Also keep in mind it may be better to have the rudder bend than break your bracket. If you run a steel rudder blade be prepared to start breaking the mount. I would advise against. You are better off findind a source of 7075 rudder blades or ask a machine shop to make you some. I know Brian Neal had to make about 50 blades for his big cats and replaced the blades when they bent or broke. That’s just part of running those cats at high speed.

[dmitry100]

Would a thinner wedge like that technically increase the speed a tad bit? I've read 5mph+ more can be possible... with a similar knife blade.

[Lone-Wolf]

I had the exact same bending issues on my HPR99's rudder, same rudder and bracket as you. I would bend it back and could get away with it a few times, I had alot of trouble finding the stock replacements, if I still had the boat I would find a machinist and order a dozen of them at least! I do think these rudders are intentionally weak because of what Tyler mentioned above, to save the bracket and transom.

BTW Do you by chance have any video of your 99 running yet? I would be really interested in seeing it in motion, I had nothing but troubles with mine I swear it was possessed!

[Fluid]

This thread has been terribly jacked, but here goes. I watched a lot of 130+ passes from several cats at the LA SAWs in 2014, and it was clear they had rudders which were too small. Most would hook out terribly at the start of each pass, spinning around and taking a lot of effort to obtain a straight pass. All had true wedge shaped rudders but they were too short both IMO and in their results. It is only the rudder which supplies resistance to provide directional control on a SAW pass, and had they added an inch to the length they would have gone straighter and thus faster. Reducing drag is important, but so is control.


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[dmitry100]

The knife blade appears to be made out of a very strong yet flexible metal... with that in mind... I think it would act as a good shock absorber on impact

But handling-wise would handling characteristics be similar to the stock wedge? That is... If I kept it slightly longer or same length.