FE Wantabe Virgin Sports Hydro Run

[questtek]

Since Brad left the lake before he could pick up a DVD of the day's run, I thought I would post a UTube video of this cosmic event. (He also missed the fatal demise of Wolf V's Elan since he to leave early)

http://www.youtube.com/watch?v=wqFQ-lqAI9s&feature=youtube_gdata

I will let Brad lie,.............err, I mean explain the fantastic run with 80+ speeds (well in centimeters per mili-farthing), and his below ambient Motor and ESC temps.

Take it away Brad.......................and tell them about the mono you are holding

[RandyatBBY]

Since Brad left the lake before he could pick up a DVD of the day's run, I thought I would post a UTube video of this cosmic event. (He also missed the fatal demise of Wolf V's Elan since he to leave early)

http://www.youtube.com/watch?v=wqFQ-lqAI9s&feature=youtube_gdata

I will let Brad lie,.............err, I mean explain the fantastic run with 80+ speeds (well in centimeters per mili-farthing), and his below ambient Motor and ESC temps.

Take it away Brad.......................and tell them about the mono you are holding

It looked good, Did you put the ride pads on the boat?

[FE Wannabe]

Joe,
Thanks for posting the video. I didn't notice it until this morning. I had a great time wish I could have stayed longer. Thanks again for allow us to run at your place, it is an awesome place to run.

Randy,
Yes this hull has your pads on it. This was the boat I showed you at the last LA SAWs in November.
Since I was experiencing a lot of bow lift on this first run I made a few changes for the second non-video'd run that was much better than the first run.
I lowered the strut down 1/8" and changed out the x438 for a high lift 38x55 Grim Racer prop and it ran 46.2mph on the Feigao 6L on 2s2p. The UL1 ran a lot more stable and turned awesome. I was able to run full throttle all the way around the oval. The only problem was that when I brought it in I was 170 degrees on the ETTI 150 caps! The external cap bank I had was at 130 degress and the batteries were 110 degrees. Unfortunately, I forgot to measure the temp of the 6L. The data logger showed that I was peaking at 131 amps which is too much for the 6L, so I may have to take it down a notch. Too bad because the hull seem to like that speed.
Hopefully you will be at Joe's (QuestTek's) place on Monday to watch it run. Maybe I can get some setup tips from you.
Thanks,
Brad

[FE Wannabe]

Randy,
Regarding the mono in the picture, it is the 36" flatbottom that I had asked you about some setup help on before. It is the same hull that Wilmer has, just bigger.
Here are the specs on it.

Hull: 36" Flatbottom with a 14" beam
Motor: KB45 8XL 1700kv
ESC: HiModel 200A no bec
Batteries: 4S1P - 2ea 2S in series
Prop: Graupner K42
Prop strut mounted to transom with prop shaft below transom so I am running 3/4 submerged

The big problem I have when I ran this boat for the first time is that the hull hops so bad I can't run it over 1/4 throttle, as the hull comes completely out of the water on each hop. I am not sure what more I can do without adding a lot of weight to the bow since I am at the max on negative angle on the strut and the COG is already close to 40% from the transom. I may have to make some major changes to get it to run at planing speeds. I will bring this boat as well on Monday.
Hope to see you Sunday at the SAWs at Legg.

[sporthydrofan]

Randy,
Regarding the mono in the picture, it is the 36" flatbottom that I had asked you about some setup help on before. It is the same hull that Wilmer has, just bigger.
Here are the specs on it.

Hull: 36" Flatbottom with a 14" beam
Motor: KB45 8XL 1700kv
ESC: HiModel 200A no bec
Batteries: 4S1P - 2ea 2S in series
Prop: Graupner K42
Prop strut mounted to transom with prop shaft below transom so I am running 3/4 submerged

The big problem I have when I ran this boat for the first time is that the hull hops so bad I can't run it over 1/4 throttle, as the hull comes completely out of the water on each hop. I am not sure what more I can do without adding a lot of weight to the bow since I am at the max on negative angle on the strut and the COG is already close to 40% from the transom. I may have to make some major changes to get it to run at planing speeds. I will bring this boat as well on Monday.
Hope to see you Sunday at the SAWs at Legg.

im having the same problem my sport hydro is 32" ... i get massive hopping at 1/4 speed if i push it past 40 it goes airborne and blows over... ive tried everything that can be done with the strut up down full positive full negative.. i even taped a 1lb bag of sand t the front spoiler..and it still hops!!! what did you do to fix that hull from hopping.....? here some pics of my setup

[FE Wannabe]

I still haven't fixed my Flatbottom hull's hopping problem, but I haven't really put anymore time in it either. These hulls are very different so what might work for one might not work for the other.
I am by no means an expert on hydro hulls. I have just started setting up the Hydro in the video, and it runs fairly well now, but I am definitely still learning.

That being said, where is your COG at in comparison to the trailing edge of the front sponsons? Are there any positive or negative angles on the front or rear wing that could be causing any lift or downforce? I can't really tell what the Angle of Attack is on your front sponsons, but from what I have heard around 3.5 degrees is optimal.
Just trying to help from my limited knowledge.
Brad

[sporthydrofan]

COG is about 2" from the sponson. there is a neutral angle on the rear spoiler, and a slight positive angle on the front spoiler.. how do i measure angle of attack? and how do i adjust it?

[FE Wannabe]

Well I just learned about how to measure it this past weekend from Randy from BBY. To measure the Angle of Attack do the following:

First get your self a perfectly level and flat surface to set your hull on.
Next, hang a sponson almost all the way off the surface, enough so you can place a digital protractor down the centerline of the sponson, making sure it touches the trailing edge. Then measure the difference in angle between the sponson and the level surface.
This angle should be around 3.5 degrees.
Adjust the strut up or down to achieve that angle.
Video of the boat hopping might help to determine the cause.

[Ub Hauled]

Well I just learned about how to measure it this past weekend from Randy from BBY. To measure the Angle of Attack do the following:

First get your self a perfectly level and flat surface to set your hull on.
Next, hang a sponson almost all the way off the surface, enough so you can place a digital protractor down the centerline of the sponson, making sure it touches the trailing edge. Then measure the difference in angle between the sponson and the level surface.
This angle should be around 3.5 degrees.
Adjust the strut up or down to achieve that angle.
Video of the boat hopping might help to determine the cause.

Keep in mind that 3.5 degrees is for SAW passes in flat water, add a little for oval setup or sport runs in rough waters...

[sporthydrofan]

measure the angle how far away from the table edge? As my sponsons extend forward they have thier own natural arc up. The measurment spot should be the flat part of the sponson pad near the sponson Stern correct?

[FE Wannabe]

measure the angle how far away from the table edge? As my sponsons extend forward they have thier own natural arc up. The measurment spot should be the flat part of the sponson pad near the sponson Stern correct?

Yes that is correct.

Thanks Jan for correcting me on the AoA. I don't want to spread any mis-information. When Randy was talking about a 3.5 degrees, I misunderstood that it just applied to SAW setups only.
Have a good one.....
Brad

[RandyatBBY]

Not true. I use 3.5 for all my oval stuff. On the low power motors I set the SAW sponsons at 5.5. like Wilmer's Novak motors and back in the day with Hackers and Nimh I used up to 6.5 degrees.

[sporthydrofan]

ok guys great news!!! i got the hopping to go away! i am very happy with the performance!

[FE Wannabe]

Great, good to hear.

What did you do to get rid of the hopping?

[sporthydrofan]

Great, good to hear.

What did you do to get rid of the hopping?

Good news!! i completely fixed the hopping! couple of issues fixed, from talking to numerous people on here and looking at everyones responses..

1. the turn fin was straight.... I put it in a vice and gave it a 20 degree bend inwards towards the hull about 1.5 inches down... result turns great and probably helps keeps the bow from hopping at higher speeds..

2. adjust the AoA to about 3.5 degrees.. that seems to be the general consensus...

3. dumped a whole can of crack filling expanding foam into the sponsons added about 1lb to the front. in my opinion the boat was too light.. cog is about 1.5 inches from the sponson transom.

over all results the boat has a slight hop at slow speeds of 15-30 mph then planes out and hugs the water as it reaches 40 mph... I think the turn fin helps stabilize that bow... i didnt get to radar it but it looks as if its getting 45-50 mph right now and i was doing laps at about 80% throttle even in the turns!

now i have another issue... i keep blowing the esc! i had 2 of them a 90a hobbywing seaking that toasted and majic smoked while testing the hops and just blew a 120 amp seaking after about 5 minutes of laps at 80% throttle the capacitors just bulged and cracked open and leaked out yellow fluid.... i get very good water flow it shoots out at least 6 inches before it hits the water.... the capacitors keep bulging and then bust open and the esc fails...

my setup incase anyone forgot

feigao 580l motor ~2400kv
hobbywing seaking 120 esc
5S1P 5 amp
octura x640 prop

why does the esc's keep failing after such little use? and what do you recomend that will take the abuse without spending over $100 .... Id hate to test out a $200+ esc and blow it...

some last advice from you guys you have been really helpfull so far! and im very happy I became a member on this forum!