Anti-stumble blocks

[Zimmerman]

Do anti-stumble blocks on F1 hulls really work that well? Any theories on size, shape, placement or effect regards c/g considering hull length?
I am really curious, Rich Z

 

[Carl Van Houten]

You should search that topic on IW. You will quickly learn that there are topics on this forum that gets some people heated up fast. Nobody can agree on if they are needed or not. LOL it gets comical sometimes. Looks like you joined this forum in 2003 so you should already know this.

 

[Grimracer]

Rich.. hope you are well.. They work quite well. The idea that the hurt more then help is not all that strong. In the END, as you know.... its about the 6 laps on the course.. get to the end with minimum hickups.

Grim

 

[Kris Flynn]

To me, they 'feather' the boat in the corners and add some 'fudge factor' when crossing other boat wakes or wakes in rougher water.

 

[Zimmerman]

Rich.. hope you are well.. They work quite well. The idea that the hurt more then help is not all that strong. In the END, as you know.... its about the 6 laps on the course.. get to the end with minimum hickups.

Grim

Doing well Grim. Sad that so many events were cancelled this year. I haven't been interested in F1 type hulls since the 70's, but have recently ordered a Thongfiber inboard gas F1 to play with. There is a video on their facebook page () showing one that will turn on a dime and give 9 cents change. If you stop the video in the right spot it apparently does not have stumble blocks. Do you think c/g is a critical factor?
Thanks all for your comments.

 

[Mike Starrett]

There are no Stumble blocks on a Thongfiber F1

 

[Zimmerman]

Hey Mike!
Yes, I know they don't come with them. John B and Jeff H have given me their thoughts on the matter as they are both running them. I did not get to see yours run, etc. since it got wrecked. Mine is due in about 2 weeks so I'm gathering setup info if you are of a mind. The one in the video really handles, but after many views it appears to me it may be because I don't think the driver ever lets off the throttle. What do you think?

 

[Samuel Hagan JR]

If Jeff Henderson doesn’t use a stumble block on his then I wouldn’t add them. His runs fantastic.

 

[Zimmerman]

Both Jeff and John B use stumble blocks and there is considerable difference in the way their boats handle. Jeff's runs a lot like the one in the video whereas John's is very touchy on the rudder (spins out easily). The straight away attitudes are very similar. That is why I think there is something else at work here. The tunnels we ran back in the day (21 and 45) did not use blocks and I cannot remember either my son P.J. or myself ever getting spun out. We seemed to be more susceptible to blow offs.

 

[Samuel Hagan JR]

I would say the setup has to be different between Jeff and Johns. Jeff’s boats seem to be the best handling boats I’ve ever seen.

 

[Mike Starrett]

Hey Mike!
Yes, I know they don't come with them. John B and Jeff H have given me their thoughts on the matter as they are both running them. I did not get to see yours run, etc. since it got wrecked. Mine is due in about 2 weeks so I'm gathering setup info if you are of a mind. The one in the video really handles, but after many views it appears to me it may be because I don't think the driver ever lets off the throttle. What do you think?

I didn't use any but found the prop makes a huge difference.. I never had to let up in a corner.

 

[Zimmerman]

Was the prop a 3 blade by any chance?

 

[Mike Starrett]

So far, I preferred a 2 blade. I don't see much comparison between this boat and my smaller tunnels.

 

[john v]

the other post on tunnel hull design talkes about stumble blocks a bit.
something like 150 replys and wow, i love ob tunnels but i was a bit dazed by the amount of info there was !
if you really want some serious tech info on design this is a great article.
i think i will have to call rod and have him explain this to me but an awesome post

 

[Kris Flynn]

The boat (thongfibre) in that video is running pretty tight on the water and is also an inboard. I do not know many inboard tunnels that run stumble blocks.

 

[Mike Starrett]

Mine ran like that. VERY easy to drive.

 

[jken1995]

I noticed on mine that on the first turn of the race or on calmer water my thongfiber was a little too unpredictable when it would take a set and make a nice corner. It tended to snap on me. As Mike S. suggested the prop choice can have an effect on this as well. As the race progressed and the water churned up it is much better. I am also running a stock setup and I believe Mike runs a mild mod. There could be a difference with the speed in the corners as Mike's definitely has more speed. It might be best to start without them and see how it works. Can always add them later. Looking forward to seeing you this weekend in St. Anne.

Jeff Henderson

 

[user 21992]

Hi Rich, the F1 hull from Thailand runs a weird course and they are set up for a one pin turn. With that said, I don't believe the stumble blocks are needed on our course set up either. Jeff started playing around with stumble block and I did also, it did help !! We both where using the CoCor SIM3/3 blade Prop and both hulls ran well with stock 26cc Zenoah's. As Mike S. stated the prop, will make a big deafferents. Rich, if you study Thongfibers site, you will see they don't deal with tree blade props much. You will also notice Thongfiber are using, what mostly looks like a copy's of the Prather P275, or, are Prather Props (thinking they bought Hyperformace out In Ca. ??). Looks like a lot of work went in to doing what they called the Peak Prop and making tons of them for the F1's and the P45 Mono's. Dan Pralle ordered a couple of Peak Props, one for his P45 Mono and one for the F1 tunnel (think his was Peak H and mine was Peak X ??). My F1 I believe dose not need the stumble blocks anymore, and runs very nice in the turns with a mid mod 26. HAPPY RACING !! Here's Peak the Prop running at Evansville, MAN !! Keenan Pralle gave me a good run !! Watch this video to the end, this was a blast !!

 

[Zimmerman]

Thanks for the info Stitch!

 

[user 21992]

Rich or any other Gas F1 Cat user, You have to get used to a new style of driving on this hull and you will have to use your transmitter functions to adjust your servo end points L-R, which will be very little travel and the most important aspect is to control the speed of your servo in relation to your transmitter wheel, slow it up !! ( or stick ). like days of old, I just cranked the wheel and boom it's gone, whip around on me. Set just a bit of negative on the strut, that will push the front of the sponsons down in the straights and turns. I also use a 1" Speed Master Rudder ( full length ) and pull back the bottom tip of the rudder back about an 1/8" at the bottom, also helps push the nose down. Another thing I have learned, is to let off the throttle slowly and slightly going into the turns, letting the right sponsons grip the water better with out hooking. Do not go into a turn at full speed, and let-off the throttle to quick, it will let the nose down to fast and spin-out. Hope this helps, the F1 Cat is fun to drive. Rapid Fire and HAPPY RACING !!