Project X Build Log - Belated - RC Groups
Shop our Airplanes Products Drone Products Sales
Thread Tools
Oct 24, 2008, 01:13 AM
Grumpa Tom
Kmot's Avatar
Build Log

Project X Build Log - Belated

I first hinted about Project X here, when I posted these two teaser photos:


I had a leftover sheetboat hull and was wondering what to do with it. Then I thought it might be interesting to convert it into a powered boat.

Then an incident at Lake Balboa started the process of making a 'fantasy' boat that would be a "sheetboat hunter-killer".

Now that Project X is finished and has been revealed, I thought it might be interesting to some of you to see how it evolved from a Mini Soling sailboat into the monster boat known as Project X. Since some of you have encouraged me to do so I am happy to oblige. More pictures!
Sign up now
to remove ads between posts
Oct 24, 2008, 01:27 AM
Grumpa Tom
Kmot's Avatar
I looked real hard at the keel, and how it was apparently installed. I then figured out it had two pieces of wood sandwiching another. So I was able to chisel those two outer pieces off and then remove the keel without damaging the hull.

The top of the keel looked as if the entire assembly was solidly filled with epoxy. NOT!!!

When I placed it on my bandsaw to cut the keel in half, out poured a bazillion trillion million micro lead balls all over my shop floor and out the door....
Oct 24, 2008, 01:44 AM
Grumpa Tom
Kmot's Avatar
The next phase was gluing the keel back into place and attempting to fair the keel to the hull. This was a learning phase for me, and I was learning that Bondo glazing putty is not good for anything other than the lightest touch-up spots. When applied thick it cracks badly. I eventually started using epoxy mixed with micro balloons.
Oct 24, 2008, 02:00 AM
Grumpa Tom
Kmot's Avatar
The filling and sanding finally came to an end. The hull was sparyed with primer, and it was starting to look good again.

While working on the motors and gear train, I discovered the plastic Graupner used was very soft and brittle and it cracked under the stress of lightly snugging the screws. I glued it to reinforce the cracked areas.

You may recognize some of the photos as having been seen before. That is because the "Project X" teaser photos were all just crops of regular photos, with the color removed and a poster type finish applied to them.
Oct 24, 2008, 08:41 AM
AndyKunz's Avatar

Jr. Branham sent me some green automotive putty a while ago that blows away Bondo. It would do what you needed - maybe on the next project. I forget the name but I'm sure you could ask him. It was a bit pricier than Bondo but well worth it.

Oct 24, 2008, 11:50 AM
Registered User
Wow, Kmot! A lot of effort went in to getting it to that point! Nice work!
Oct 24, 2008, 12:23 PM
Grumpa Tom
Kmot's Avatar
Everything is an extremely tight fit in this boat. And when you have large stubby hands and fingers it ain't easy to work in tight spots!

I installed the motor system into the hull, and using a syringe with a silicone tubing extension I reached waaaaay into the stern and poured the epoxy over the stuffing tubes. I used tie-wraps to secure the gearbox housings to the wood motor mount.

To install the rudder horn, I had to make a custom horn from a model airplane bellcrank, and then use a hemostat to reach in and secure it to the top of the rudder post.

I never expected I would ever have to pull a motor out of this thing. Both units were brand new in the box before I installed them in this hull.

Well guess what? In the first testing in the pool, one of the motors burned up. ALso, scored the prop shaft and stuffing tube. I discovered the motor was at fault due to a manufactuing defect. The armature was out of round. It was rubbing one of the magnets inside the can. The out of round condition caused the propshaft and stuffing tube to score and gall each other.

Did I say it was a tight fit? You should have seen how tight a squeeze it was to get a motor out of there without taking apart the entire assembly. But I did it. It was impossible to find another Graupner Speed 600 8.4V bushed motor anyhere at the online retailers. I put out a wanted ad and fortunately another RCG member had a NIB motor he sold me so I was back in business.

The next test in the water went well. Too well.......
Oct 24, 2008, 12:43 PM
Grumpa Tom
Kmot's Avatar
So, with both motors working as they should, the boat had power. Way too much power, because under full throttle the hull would rise up toward the sky, and then fall and roll over to the right. It was basically uncontrollable. Something had to be done, and I came up with the idea to use outriggers.

Nothing was available commercially, so I had to make them from scratch. I looked around my shop and saw a piece of styrofoam flotation that I had removed from my Atlantic tug hull. The edges of this piece of foam looked like they would work as outriggers! So I cut the edges off and started making my pontoons.

While creating this fantasy boat, I had to keep in mind that it would have been built by a 'monster creature' and so would not have been built with exacting dimensions and precision. Uneven surfaces, non-symmetrical parts, etc would be the norm. Actually, this suits my building style to a "T" because I basically build like a dumb monster.
Oct 24, 2008, 12:56 PM
Grumpa Tom
Kmot's Avatar
I did some trimming of the epoxy around the tubes and then painted the ponoons in primer. I wanted to keep it light at the rear and used aluminum and carbon fiber tubes. I placed them where I thought would give then best advantage to control stern squat as well as rolling trendency. I taped them in place and tested the boat in the pool. It completely solved the problem of rising up and falling over. Instead it accelerated brutally and turned like a Formula 1 racer. I liked it!
Oct 24, 2008, 12:58 PM
Grumpa Tom
Kmot's Avatar
Jr. Branham sent me some green automotive putty a while ago that blows away Bondo.
Thanks Andy!

Wow, Kmot! A lot of effort went in to getting it to that point! Nice work!
Thanks Aero!
Oct 24, 2008, 01:11 PM
Sea Dragon-Lover
Umi_Ryuzuki's Avatar

Great build up shots.
Perfect launch timing for Halloween...
Oct 24, 2008, 01:43 PM
Capt.Crash's Avatar

Verrrrrrrrrrrrrrry interesting Tom!

You get a "A" for creativeness!

I will be very curious about how those pontoons work. I would l think they might work ok at slower speeds...but at high speeds if they catch a wave wrong? got any more info on the green putty? Does it smell better than bondo?

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Poll Stryker F27-X Build Log Taoweiji Flying Wings 53 Jun 18, 2010 07:42 PM
Build Log Build Log - ARK X-500 series build thread cfrank2005 Electric Heli Talk 30 Jun 29, 2009 01:27 PM
WTB: Matney Models Project X JFisher304 Aircraft - Electric - Airplanes (FS/W) 3 Feb 05, 2005 03:14 PM
Project X... or what happens when you strap an 010 onto a MSW? Tres Wright Parkflyers 114 Nov 17, 2003 05:06 PM
Project X Chris True Electric Ducted Fan Jet Talk 6 Nov 10, 2001 10:58 PM