Hotrod Delta Force Mini-Sniper

[properchopper]

After building one boat for Dave, he trusted me enough to build him a "hyper" 23" Mini-Sniper to replace his last one which had an unfortunate encounter with the Archimedes Principal. He collected and sent me just about everything except a motor, motor mount, and strut. Having a very positive experience recently with a TP Power motor, I elected to go with a TP Power 2935 6Y motor of 2270 KV to run on 4S with his Seaking T-120. Figured it'd be just right to run at a good rpm with his razor sharp 435/3 prop.

With Keith out setting SAW records I couldn't ship him the hull and hatch to lay in the CF so I had a go myself. While a fun extravaganza, I'd much rather occupy my time with a considerably easier and less frustrating task like teaching my dog to twerk while accompanying himself on the accordian

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[properchopper]

Next up was to shorten the Speedmaster stinger to get the drive dog even (or close) to the rudder leading edge.

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Then, time to install the rudder, which had two out of three bolts of the "blind hole" variety so I broke out the Silly Putty and marked the drill locations.

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To make life easier when torqueing down the rudder, I made rudder mounting studs from some 3mm x 35mm bolts so they could be "nutted" from the inside. Felt pretty clever after that, PLUS the rudder base had such a tiny footprint so I made a cf-plate gasket to better distribute the side-torsional loads should they occur Did the same for the stinger base 'tho not really needed Added the nicely tapered tabs and did the turn fins which I laser aligned with my extravagantly priced super Hi-tech $3 HK laser

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[properchopper]

After a full component mock-up I decided to go with a rear motor layout [Randy taught me that years ago] so the shorter drivetrain has less friction and batteries can be used to adjust cg.

Planning several steps ahead to tighten up the servo & waterlines I prepped the motor mount with side holes to hold epoxy better, larger holes to pass servo wire underneath, and holes to run waterline under motor. Pre-made epoxy dams for a better motor mount-to-hull bond.

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Also installed 3mm threaded studs into the motor to make nutting in the motor nice and convenient rather than fussing with trying to get allen bolts started in the limited space of the rear motor location

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[properchopper]

My next fun-filled extravaganza came when I discovered I was sent a MICRO servo with the mount for a slightly larger MINI servo. After several hours of head scratching trying to source a top-load micro-mount (needed for the cramped space the servo would occupy) I gave in and fabbed a mount to fit with parts from the bigger mount

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Made battery trays from 3/32" birch ply with shims underneath to allow one-wrap to encircle trays and batteries. Yeah I know, CF are Mo' Trick but 'Mo expensive and are largely unseen once installed and velcroe'd.
OK so I used a CF ESC platform, Happy ?

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[rickwess]

Next up was to shorten the Speedmaster stinger to get the drive dog even (or close) to the rudder leading edge.

I've always wondered why manufacturers don't match their components. SM doesn't make a rudder bracket to match their 3/16" stinger.

• Did you use a cutoff wheel and a grinder to camfer the edge?
• How far is too far to cut a stinger? To the first step?
• Do you shorten the bushing by the same amount?

I hope you don't mind the questions as you post your build. I'll be starting my first from scratch build soon and am eager to learn.

[properchopper]

To retain the hatch, given the occasional warp-speed acrobatic manuevers these little hulls are capable of, I made some aluminum base pieces to be epoxied under the rear deck and tapped for quick-to-operate thumbscrews to work in concert with a solidly strong tab on front.

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[properchopper]

Here's a little mod you'll love if you've ever spent an entire entertaining afternoon trying to thread a Rx antenna under the deck up inside the tiny antenna tube that's permanently mounted. I press-fit the antenna base nut into a piece of ply, epoxy under the deck, allowing the antenna to be fed up the larger (now threaded) hole, and inserted into the antenna base/mast which gets screwed in betwixt thumb and forefinger

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There's so much more but my typing finger is getting tired SO here's the interior shot

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[properchopper]

Finally : The "Beauty Shots"

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[properchopper]

The Last Word

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Thanks for looking,
Tony
rcboatbuild@hotmail.com

[properchopper]

I've always wondered why manufacturers don't match their components. SM doesn't make a rudder bracket to match their 3/16" stinger.

• Did you use a cutoff wheel and a grinder to camfer the edge?
• How far is too far to cut a stinger? To the first step?
• Do you shorten the bushing by the same amount?

I hope you don't mind the questions as you post your build. I'll be starting my first from scratch build soon and am eager to learn.

I just hacksaw the tip off the stinger & dress on the face grinder of my belt sander.

I usually go as far as in the picture. You'll want to have enough length to support the propshaft as much as you can

Yes, you need to shorten the bushing

[ray schrauwen]

Nice job Tony. I learned a few good ideas for my next build on a boat any size

[rickwess]

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Lots of good info indeed. I understand the blind nuts epoxied in for the thumb screws, but what the part on the top? How does the hatch sit flush with that there?

[properchopper]

Nice job Tony. I learned a few good ideas for my next build on a boat any size

Hey Ray,

You gave me some good input on motor choice before I got started

[properchopper]

Lots of good info indeed. I understand the blind nuts epoxied in for the thumb screws, but what the part on the top? How does the hatch sit flush with that there?

Not sure I understand your question - but if you're asking about the clearance issue, the hatch has a raised edge which lifts it above the tapered thumbscrew guide

[Rocstar]

Also installed 3mm threaded studs into the motor to make nutting in the motor nice and convenient rather than fussing with trying to get allen bolts started in the limited space of the rear motor location

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Tony, what keeps the studs from turning while installing the nuts, just Loctite?