My 1/4 Scale DPI Tunnel Running Pics

[Mike Luszcz]

Went to the pond last night, and a friend of a friend brought his camera out..really nice camera I must say, and got these pics. The Blackjack 55 is doing 52mph consistently, and my Cal Spas is is running right at 40. I have the proper size prop on its way and a tuned pipe on its way, so I hope to see more speed soon. I give many props to the previous owner for the quality of the paintwork. The boat is just looks fantastic to me. I usually like to build my own stuff, but couldn't pass up this boat..not to mention its hard to get the BIG Tunnels it seems..Well, Enjoy!

 

[steath assassin]

That's cool. I like to see those big boats running good. How do they both turn?

D

 

[JoseBaquero]

cool pics bro

 

[Pete Markese]

Mike, you shouldn't be asking me questions about set-up on a 3.5 tunnel...from what I see in these pics of your 7.5 DPI, it appears that you know what you're doing...I should be asking for your advice!

Pete

 

[Mike Luszcz]

Mike, you shouldn't be asking me questions about set-up on a 3.5 tunnel...from what I see in these pics of your 7.5 DPI, it appears that you know what you're doing...I should be asking for your advice!
Pete

Pete,

Believe me, I am no expert..just starting in this whole Outboard scene..and I love it! I got my tuned pipe on it a couple days ago..ran it and tuned it last night..now its doing at least 50mph..gonna radar it on sunday, but I cannot keep the front down. I have lowered the back of the outdrive to create downforce, but the boat is just so light it wants to ride up, then catch a little wind and its over. I am going to add some weight to the front, but its crazy. I would have never imagined the fine line these boats have. I know its fast tho!

I do have a question for the guys in the know....Stumble blocks..Do they help keep the front down because they limit air flow under the boat, or are they mainly to stop turn hooking..which this boat does bad as it is! Also, how do you determine the size blocks you need? Any help would be great...Also, if anyone has any 11cc pistons and sleeves, and rods, or any other various 11cc parts they want to let go, please run that by me, as I have no extras, and I am worried that this engine is going to run threw parts rather quickly. I could be wrong about these K&B's but they seem rather violent at full rpm, and I cannot imagine their run life to be overly long.

Thanks guys, Mike

 

[ryan_t888]

That's an excellent looking hull.

The recovery pads/stumble blocks IMO do not help keep the nose down. Adding weight to the front of the hull will help. I find tunnels to run best when the CofG is around 30-35%

As for size, it ranges from hull to hull as some don't need as much as others. I find the recovery pads work best when their length is about 15-20% of the total hull length.

Ryan

 

[moparbarn]

from looking at the first pic, i'm not sure you have much down adj. left. but, that being said, lowering (not tilting/trimming) the motor down will help keep the nose down. but, at the same time, it will run "wetter", more of that fine line thing. i would try to keep the tilt/trim as close to level as you can, maybe 1 degree down, & do the rest with motor height & balance/cog. sweet looking paint scheme! that's what i enjoy about tunnels, they're never "dialed in", constant adjusting for wind & water. more of a challenge than just fire it & run it. but then, i like to tinker & play with the limits..................

 

[SayMikey]

from looking at the first pic, i'm not sure you have much down adj. left. but, that being said, lowering (not tilting/trimming) the motor down will help keep the nose down. but, at the same time, it will run "wetter", more of that fine line thing. i would try to keep the tilt/trim as close to level as you can, maybe 1 degree down, & do the rest with motor height & balance/cog. sweet looking paint scheme! that's what i enjoy about tunnels, they're never "dialed in", constant adjusting for wind & water. more of a challenge than just fire it & run it. but then, i like to tinker & play with the limits..................

When your ready for another hull i have a new one that needs to go.................

 

[steath assassin]

from looking at the first pic, i'm not sure you have much down adj. left. but, that being said, lowering (not tilting/trimming) the motor down will help keep the nose down. but, at the same time, it will run "wetter", more of that fine line thing. i would try to keep the tilt/trim as close to level as you can, maybe 1 degree down, & do the rest with motor height & balance/cog. sweet looking paint scheme! that's what i enjoy about tunnels, they're never "dialed in", constant adjusting for wind & water. more of a challenge than just fire it & run it. but then, i like to tinker & play with the limits..................

When your ready for another hull i have a new one that needs to go.................

A DPI???

 

[SayMikey]

from looking at the first pic, i'm not sure you have much down adj. left. but, that being said, lowering (not tilting/trimming) the motor down will help keep the nose down. but, at the same time, it will run "wetter", more of that fine line thing. i would try to keep the tilt/trim as close to level as you can, maybe 1 degree down, & do the rest with motor height & balance/cog. sweet looking paint scheme! that's what i enjoy about tunnels, they're never "dialed in", constant adjusting for wind & water. more of a challenge than just fire it & run it. but then, i like to tinker & play with the limits..................

When your ready for another hull i have a new one that needs to go.................

A DPI???

Yup a DPI no holes drilled need it?

 

[moparbarn]

derrick prolly don't NEED it, but i'll betcha he WANTS it .

 

[Mike Luszcz]

Yeah, I would like to have it to, I just cant swing it right now. I ended up getting this boat instead of your hull. Hence why I never got back up with you about it....Sorry about that by the way. Mike

Yeah, I have it trimed all the way down. I have some stick on wheel weights I am going to try next time I get it out..hopefully in a day or two. A tuned pipe has been added now and from what I have seen, if it was doing 38 mph without the pipe and a huge oversized prop, it is doing every bit of 50+ with the pipe and a P235 and P240. Anyone know what a setup like this should be running?

 

[Body Guard]

Hi People,

I have built many rc tunnel for years and never really like to add weight to the bow. In all my build I have incorporated calculated hooks of varying length and shape. It has worked really well for me with true horizontal prop shaft trim to maximise power output.

Please click on this link below to see the effect of such application. Need only a small amount for IB but relatively more for OB.

Just my two cents worth.

 

[Body Guard]

Hi People,

I have built many rc tunnel for years and never really like to add weight to the bow. In all my build I have incorporated calculated hooks of varying length and shape. It has worked really well for me with true horizontal prop shaft trim to maximise power output.

Please click on this link below to see the effect of such application. Need only a small amount for IB but relatively more for OB.

Just my two cents worth.

http://www.youtube.com/watch?v=VuPZxIF4mVY

 

[Mike Luszcz]

Hi People,I have built many rc tunnel for years and never really like to add weight to the bow. In all my build I have incorporated calculated hooks of varying length and shape. It has worked really well for me with true horizontal prop shaft trim to maximise power output.

Please click on this link below to see the effect of such application. Need only a small amount for IB but relatively more for OB.

Just my two cents worth.

http://www.youtube.com/watch?v=VuPZxIF4mVY

Could you explain "hooks of varying length"? What are hooks? Please show a pic, or explain what that term means. Thanks, Mike

 

[Body Guard]

Hi People,I have built many rc tunnel for years and never really like to add weight to the bow. In all my build I have incorporated calculated hooks of varying length and shape. It has worked really well for me with true horizontal prop shaft trim to maximise power output.

Please click on this link below to see the effect of such application. Need only a small amount for IB but relatively more for OB.

Just my two cents worth.

http://www.youtube.com/watch?v=VuPZxIF4mVY

Could you explain "hooks of varying length"? What are hooks? Please show a pic, or explain what that term means. Thanks, Mike

Attached is a sketch I have just drawn to show you the meaning of the term. The first one is just a normal hook while the 2nd and 3rd are hook and transom lift incorporated together. It makes the hull stay at a low and safe alpha angle when in full flight lessening the risk of a 'blow over'.

Tunnel_Kline_hook.ppt

 

[SayMikey]

Hi People,I have built many rc tunnel for years and never really like to add weight to the bow. In all my build I have incorporated calculated hooks of varying length and shape. It has worked really well for me with true horizontal prop shaft trim to maximise power output.

Please click on this link below to see the effect of such application. Need only a small amount for IB but relatively more for OB.

Just my two cents worth.

http://www.youtube.com/watch?v=VuPZxIF4mVY

Could you explain "hooks of varying length"? What are hooks? Please show a pic, or explain what that term means. Thanks, Mike

Attached is a sketch I have just drawn to show you the meaning of the term. The first one is just a normal hook while the 2nd and 3rd are hook and transom lift incorporated together. It makes the hull stay at a low and safe alpha angle when in full flight lessening the risk of a 'blow over'.

Cant open it try using PDF not ppt

 

[Body Guard]

I'm trying to load the file different format. Doesn't work as yet after 4 trys. At the moment I don't have explanatory pic.

 

[Body Guard]

I'm trying to load the file different format. Doesn't work as yet after 4 trys. At the moment I don't have explanatory pic.

Mike,

You managed to get the sketch downloaded ? I can see a lot of downloading done already.

Hope it is of some use to you or anyone else for application on their high alpha running attitude. If you need more info just shout

Body Guard

 

[steath assassin]

Some also call one simular to one of the drawings a pencil roll.