32" Wild Thing build thread

[Dirk Jan Cozy]

@XtremeRcBoats : yes, I have looked at the plans and Jeff's article for inspiration. Actually, Jeff converted his original Wild Thing from the article to electric and beat a few records for oval and SAW if I'm not mistaken.
It is a great boat and I have a lot of fun with it.

After a few crashes I decided to reinforce the deck and hatch. Added another rib under de deck, left and right:



Laminated a 200gr/m2 carbon weave under the hatch:



The hull can take quite a beating now. I know from experience . I ran it last weekend and had 4 crashes and flips. I even managed to land the Wild Thing on the shore. Luckily no damage. The wooden rudder bracket holds up as well .

Here's the video of the last run.



Above approx 50mph the hull becomes unstable. I think it could use a little more down trim on the stinger. Also, I will add trim tabs to try reducing the prop torque.

By the way, I gained 5 km/h with the same setup, just by finishing the bottom hull and sanding it with 600 grit sand paper.


97 km/h with a 443 prop and B-grade 6S lipo.
I got 113 km/h this run with the 644 prop and CNHL 6S 5200mAh lipo.

 

[Dirk Jan Cozy]

I installed trim tabs to see if I can improve the hull stability (reduce prop walk). It was a tight fit and I had to cut the trim tab bracket a bit.



Last weekend I ran the Wild Thing with the trim tabs for the first time. It definitely makes the hull more planted. I have to experiment a bit more on the angle and the height, to find the best balance.
I made a video of the test. I also run a 3 blade 44mm 1.4 pitch prop for testing:

 

[john v]

Thanks John. The wooden rudder bracket is an experiment to see if it holds up. It does have a few layers of glass to reinforce it. So far so good, it survived a few crashes already.
Im interested in your setup; did you run trim tabs? How about strakes? I experience some instability, mainly due to torque roll. I don't use trim tabs and strakes yet, but I'm now in the process of making strakes.

sorry for the late reply, i built my wild thing in 1999 and set up the boat per john finchs pictures, stuffing tube extended beyond the transom, aluminum sheet metal trim tabs and no strakes, john said strakes might cause lift which i did not want, in my case i think weight up front would have calmed the boat down, last time i ran it was powered by a nova rossi 35 plus 21 nitro motor with a sholund 1614 cleaver prop, it was fun running a hull that is almost 25 years old!

 

[Dirk Jan Cozy]

After many flips, crashes and hard landings, the wooden rudder bracket finally broke. It lasted longer than I expected.



I made a new bracket from aluminium. I made it with basic tools, from a solid bar of aluminium. Its 20mm longer than the old bracket. I hope to improve the cornering by placing it behind the prop.

 

[john v]

i like the aluminum bracket but the wood one, work of art!

 

[Dave Gilles]

i like the aluminum bracket but the wood one, work of art!

agreed. beautiful....

 

[Dirk Jan Cozy]

Thanks! I might make another wood bracket. It was actually quite durable and also very light.
I made so many flips and crashes before the bracket finally broke..

Or I might make one from carbon fiber, just for the fun of making a bracket from 3 different materials .

I will try the aluminium bracket this weekend.

 

[john v]

different length brackets will affect the handling of the boat, havnt tried this but you will see the results

 

[Dirk Jan Cozy]

Yes, I am curious what the longer bracket will give. I will make a video about it.

 

[Dirk Jan Cozy]

Here's the video of making the bracket. I also made a bigger rudder blade and smaller turn fins. I will test them all soon.

 

[XtremeRcBoats]

Looks great, you're very skilled.
Normally you make mostly right hand turns, so the left turn fin can be smaller then the right side turn fin.

 

[Dirk Jan Cozy]

Thanks Xtreme, also for the turn fin advice. I might try that, as I have long and short fins now.

 

[Dirk Jan Cozy]

I tried my new rudder setup with great success. Cornering improved by using the longer rudder bracket and the wider rudder blade.

I also broke my speed record, reaching 116km/h.

Here's today's video of the testing and tuning:

 

[Dirk Jan Cozy]

Hi guys, I improved my Wild Thing again by installing a high precision motor collet. This ER8 collet is originally intended for CNC milling, but it works great for boats as well. The vibration of the coupler/ flex shaft has been reduced now. You can see the difference in slow motion video recording and the boat became more quiet as well.



I took the Wild Thing out for some speed runs and finished the run with some oval running. I got a PB with 117km/h or 73mph.




I love this boat. Runs like a bullet in a straight and corners well too. Thumbs up for John Finch his design

Here's the video of that run:

 

[john v]

seeing that you changed the length of the rudder bracket you can try to shorten the rudder blade length, this will affect the speed and tuning ability. this does make a difference!

 

[Dirk Jan Cozy]

Good advice John, thanks! I will definitely try that next time. Making a carbon fiber rudder blade is easily done.

 

[Peter Wibe Enevoldsen]

the wooden rudder bracket was amazing!

 

[Dirk Jan Cozy]

seeing that you changed the length of the rudder bracket you can try to shorten the rudder blade length, this will affect the speed and tuning ability. this does make a difference!

You were absolutely right John. I made some speed runs this week. I got 73mph with the default rudder.

I then installed a 20mm shorter rudder and I got 77mph!
The shorter rudder caused more bow lift though (I could have figured, less drag against the rudder) and I made a major crash. Luckily the damage is not too bad. This boat will be running soon again!

Here's the video of that run:

 

[Dave Petrich]

You were absolutely right John. I made some speed runs this week. I got 73mph with the default rudder.

I then installed a 20mm shorter rudder and I got 77mph!
The shorter rudder caused more bow lift though (I could have figured, less drag against the rudder) and I made a major crash. Luckily the damage is not too bad. This boat will be running soon again!

Here's the video of that run:

The pond is too small to get peak speed! Its still going faster when you get to the end of the pond.

 

[Dirk Jan Cozy]

You are right Dave, I felt the same. Being able to hold the throttle longer, will probably give me a few more mph. Actually, the pond is bigger towards the left, but it is full of water plants in this season. I will definitely try it when the pond is clear again.