Delta Force Sniper 45 - Gas Mono

[Darin Jordan]

Looks good. Mine would bow steer and was little darty in the mill but would settle down once I got her to heat racing speed. I played with the EPA and dual rate on my transmitter and she behaves much better in the mill now. I have my stinger mounted dead center and a bit lower with no ill effects. What prop are you using?

Mine was REALLY bad in the mill, and was OK if you kept the throttle PEGGED the whole time, which wasn't really drivable in race conditions. The second you'd try to slow down an bit, ZING, around it would go... violently whipping around at times.

My CG is measuring to be about 31%... 13.75" from the transom without any fuel onboard. Seems pretty close to where it's suppose to be, but it COULD be too far forward.

There were two LARGE hooks on both sides between the transom and the ends of the strakes. I have those almost completely filled in and the bottom is pretty flat in this area now. Took a lot of filling and sanding. I have a layer of 6oz Carbon Fiber in the bottom inside, and the sides and bow are filled in with 2-Part expanding foam, so the boat is rigid as can be now.

I have the strut and the tabs set to neutral right now.

Prop I was running was an ABC 2614/3. I also have a 2514/3, and an X470. I might try to borrow and X472 this weekend, per your suggestion, and see how that works. It has been suggested that the 2614/3 might have had too much lift and been contributing to the issues I was having.

REALLY like driving these big gas Monos, so I'm hoping I can get it setup well enough to have some fun with.

[Chilli]

Cool. Let us know how it works out. I started out neutral on everything also. The only thing I have adjusted is going down a 1/2 turn on the strut and packing the IV bag full of fuel to settle the bow down a little bit more. But like you said, she likes to ride high on the water and that sometimes gets the boat in trouble in sloppy heat racing water. Good luck!

[sailr]

Darin,
I feel like a complete idiot! Disregard my comments about the offset. I went back and looked at your pic again and your are offset to starboard! I must have been lookin out my bad eye!

I've never seen a boat with the offset on the port side. The prop rotates CCW, just like an FE boat. With it offset to the right (starboard), it puts more lift on the right of the hull, countering prop torque, which would try to roll the hull to the right. That's how I've always seen it done. I didn't install this hardware, it was on the boat when I got it, but it's consistant with every other Mono I've built in the last several years.

V-Ing the keel is the big experiment here. The Delta Force hulls ride way up out of the water, and the 45" Sniper has a HUGE rounded keel on it, which, in my opinion, makes it unstable at speed. The boat rides way out of the water on the surface, making it more susceptible to surface "irregulatirities". The better handling boats I've seen have V-d keels, that stay in contact with the water, stablizing the boat. Might not be QUITE as fast, but I'll take handling over sheer speed, especially when racing closely with other boats. Thinking that "slicing through" will proove to be better than "riding on top of"... We'll see!

[Chilli]

You just needed to be upside down.

[sailr]

Upside down, backwards, and on wacky juice!

[Doug Smock]

Doug,

Thanks... Yes, I'll have my sanding blocks with me. In your experience, do you think it'll need some rounding?

I have a Speedcraft mono that had a keel as sharp as yours and the boat just couldn't find a happy place on the straight away. It would lay on one side or the other but wouldn't ride on the keel.
A couple of strokes with a pocket knife (I know , sounds terrible doesn't it?)lol
And some finishing touches rounding it off with a sanding block and it was a different boat.
You know how it is though, your Sniper may do fine just like it is.

Let us know how it does.
Good luck!
D.

[Darin Jordan]

I have a Speedcraft mono that had a keel as sharp as yours and the boat just couldn't find a happy place on the straight away. It would lay on one side or the other but wouldn'd ride on the keel.
A couple of strokes with a pocket knife (I know , sounds terrible doesn't it?)lol
And some finishing touches rounding it off with a sanding block and it was a different boat.
You know how it is though, your Sniper may do fine just like it is.

Let us know how it does.
Good luck!
D.

I'll keep that in mind. I've heard that before. Sanding blocks will be at the ready!!

[sailr]

"back in the day" when I ran nitros with Herb Stewart, he put a flat spot about an inch either side of the keel at the stern on the glass boats he made and sold. That really settled the boats down and stopped the 'hunting' by giving it a pad to ride on

"Something" like this

[properchopper]

Darin,

Just caught this thread ; maybe watching the ride attitude/cg setting on Bill's boat may shed some light. Pretty sure the bottom of his boat is untouched - boat IIRC was built for Bill by Paul Pachmeyer. I've seen this boat heat raced; hips get to rockin' but stays unaffected in general.

http://www.youtube.com/watch?v=-8_HW7Derv4

[Punisher 67]

Very nice build Darin , hey the turn fins where did you get those . I am going to be starting my second Sniper build with a 3080/7 and have those turn fins on my first Sniper , I would kind of like to keep the running hardware the same on both boats .

I cannot remember where I bought my first set .

[Chilli]

Peter, those look to be the Speedmaster gas mono turn fins if not a similar design.

Darin, I replaced the Zen grey coil with a RCMK unit. Works great and it has a longer spark plug wire. I now have the coil mounted on top of the pull start using the relocater bracker and have plenty of length for the spark plug boot to approach the plug from the rear. Much less of a PITA now when I have to pull the motor.

[Punisher 67]

Thank you..................................

[Darin Jordan]

Well, after some wild rides early on Saturday, and having to have Brian Buaas thrash on the carb on Saturday night to replace a bent throttle shaft (and do one of his custom carb mods which REALLY boosts drivability!), I got the boat out there on Sunday and WOW!

Started out with everything neutral, and the boat was WAY too flightly and loose. Starting turning down the inner tabs, which, frankly, on mine I think are too small, and mounted up too high off the bottom of the hull. After putting about 4-turns into them, and putting some negative into the stinger, AND moving the stinger down in it's slots, the boat became drivable and predictable. Still a little bit of chine action in rougher water that I need to sort out, but overall, it was a great improvement. Every now and then it'll still take a hop and come down on the bow and dart. We'll have to see if I can tune that out.

I think the boat is actually too small for the power available, and it needs to have more weight added along the keel at the CG. Am going to tinker on it and see what I can do.

I may also look into geting some larger tabs. Mine are fairly narrow compared to the ones pictured above, and are also a little shorter.

I have some video of the boat in action that I'll get posted shortly. I'm completely sold that the V'd bottom makes for a MUCH better driving boat, and much more racable. Time will tell...

[Darin Jordan]

Here is the only video I got this weekend. There was some confusion at the start. I went a little wide through one, and then the boat took a terrible hop through two, and almost drove into the infield, but I caught it. Meanwhile, if you look carefully, you'll see that the boat in lane two at the start, jumps out across the bow of the yellow cat in lane 3, washing it down. The cat was forced to dive into lane 2, and I may have washed him down a bit as well. Felt really bad, but watching it back, SLOWLY frame by frame, other than going a little wide, and having the bad hop which I had not control over, I don't think I did anything REALLY terrible. I'm sure I'll get better as I get the boat settled down and get some time.

The way the club works is that if you are the only boat running, after 3 laps, your done... that's why I only do the three...

[RaceMechaniX]

Darin,

A couple of suggestions: of the few non-FE sniper's I have seen run there were some common tricks that seemed to work well.

1. 2 pairs of long wide trim tabs. At least the SM 1.5"x1.5" ones. Tabs set with a little negative and about a 1/32" above the transom. Training wheels on the inner two helped. It looks like you are running N2 tabs on a T size boat.
2. 5" or 6" offest rudder. In rough water a rudder flag using 4" of your favorite radio box tape afixed below the water inlet. This helps keep the nose from lifting too much. 4" of tape from the trailing edge seems pretty good. Shorter and the effect is less, longer and attitude should be pretty consistent, but slower.
3. Use at least a 500mL or 1000mL or equal size hard tank just in front of the started cup and top it off. Or add 12-16oz of lead in front of the starter cup.

Octura X series seem to work well. X472, X467 pitched up or a X670 if your motor has some grunt. I have alsoe seen a 2914 and 3014 work too, but these were with stump puller motors without much high RPM.

Tyler