4 prop expresscraft 60inch

[ScarabChris]

Excellent! I love out of the ordinary boats.

[ron1950]

after watching your vid i see u have a fleet of giant boats...must grow em big in VC

[calcagno45]

Very nice choice on electric components! Top of the line is the way to go!

[ojb]

cant wait to see it go top job

[rearwheelin]

Your week is up......video please !

[bedrock]

Randy

Have not got this baby out yet - been windy....... busy at work

will try this week... - Hope she goes - got no idea what speed to expect??

Dean

[andym]

Come on Dean, enough teasing mate. Just be careful when you get the dog to ski behind it !!

[derektheshop]

wow unbelievable great build

[rearwheelin]

Randy

Have not got this baby out yet - been windy....... busy at work

will try this week... - Hope she goes - got no idea what speed to expect??

Dean

I think she should be in the 70 mph range, but she is going to want to move there super fast so watch for a light front end ! Even if your moving at 50 mph + and then hammer it she can get light and a big boat like that can pack some uplift and go over......I have done it a few times trying to pop wheelies ! Its going to get crazy fast !!!!!!!!!!!!!! P.S. You will need to watch the turns when accelerating through them because the thrust footprint on the transom is wide and the boat has a tendancy to straiten out so don't push it to hard close to a bank ! Late apex then throttle up 3/4 into the turn and watch her fly !

[Old School]

Bringing an old thread back to life. My son recently purchased this bare hull on eBay and it arrived today. Considering the phases this hull has been through with its checkered history, the hull was in surprisingly good condition with nothing major wrong with it. No longer did it have its multiple Scorpion motors or its dual EDF propulsion units. The hull was received bare.

Odd that the hull did not initially receive a gasser motor as the original purchaser fitted the four Scorpions, however, even with no evidence that rails had been fitted, the hull interior looked like a gasser had been used. The interior looks to be greasy as if fuel and oil stained.

As received the upper half of the hull was painted red. Upon removal from its packing the colour turned out to be a painted matte red vinyl overlay and was peeled off extremely easily revealing a hull in surprisingly good condition.

I set about removing some of the blobs of 5 minute epoxy and RTV sealant used to fill in the holes originally drilled for the four struts. It is intended to inlay the hull with a carbon fibre inlay as the hull is surprisingly thin for such a large boat. Remember this is a 60" hull.

My son has sourced Speedmaster 1/4" nitro stingers for it. The plan is to fit the two spare Turnigy (Proteus) T20 motors that I have as well as the 1/4" flexshafts and motor mounts originally purchased for a stillborn project. I have seen a You-Tube video of a similar Expresscraft 60" hull with the same two stingers and performance was more than acceptable. The hull in the video did bounce around a lot like a cork bobbbing on the water so ballast weight with multiple batteries is obviously needed.

I took a couple of images to give an idea of the hull in its current configuration. This, no doubt, will be a long term project. It is good to see that old boats never die.


Edit: I believe that the hull is now called an Expresscaft Supercat.

http://expresscraft.com/supercat.htm

Edit 2: this is the same style hull with different canopy

https://www.youtube.com/watch?v=cCOgKRUVRKo

[Beaux]

Bada$$ boat. Where did you find the lock down pins for the cowl.?

[Old School]

Bada$$ boat. Where did you find the lock down pins for the cowl.?

The pins were supplied with the hull so unfortunately I have no idea where they were sourced.

[CraigP]

Wow, never seen someone run an RC boat so close to kids in water... I bet I’m not the only one questioning that decision! But a beautiful boat and twin screws look more than enough to get that lady going!

[Old School]

Craig,
there is a part 1 video on his You-Tube site where he goes even closer to the children at even faster speeds before turning about. Nice boat but definately unsafe operating practices. My son advises the motors and ESC on the boat are extremely expensive offerings from Europe. The part 1 video description states the hull weighs in at 36 lb so I am surprised how bouyant the hull is. It seems too light.

[hughb]

Bada$$ boat. Where did you find the lock down pins for the cowl.?

http://www.rcboatbitz.com/index.php?...oducts_id=1205

[Old School]

It is amazing what a little elbow grease can achieve. When received yesterday the interior was very dirty. An hour of scrubbing, removing loose 5-minute epoxy and RTV sealant and the surface is now much better.

The port side sponson tip had about 1/4" missing so this has been built up. The port side forward corner of the hatch cutout had a 1 cm crack. I sanded back through the gelcoat to the base fibreglass and the crack was still evident, so the area was ground out and now filled. I cannot detect the crack going all the way through the skin but will reinforce the underside later just to be sure.

[Old School]

Some progress has been made however a severe medical emergency in the family has meant that I have been visiting a close relative in the hospital most of the last four weeks. A carbon fibre inlay has been accomplished plus carbon fibre vertical struts fitted under the forward deck with install to be finished by my son (it is his boat).

Today I set about fitting the stuffing tubes. Perhaps by sheer luck, alignment is less than 5 mm apart over a distance of almost one metre, inferring that the tubes are parallel. I check with two lengths of one metre 6 mm carbon fibre rods shimmed inside the stuffing tubes and extending aft beyond the transom. After the motor mounts have cured then I will remove the motors and then finish the install on the stuffing tubes, cutting them to length.

When installing stuffing tubes I like to use the next size up brass tubing (in this case 3/8" O.D.) and bond this in the transom. Once cured this acts as an anchor to enable setting up the 11/32" stuffing tubes. I finish the larger 3/8" tubing sleeve flush with the transom outer face. The stuffing tube then extends approximately 2 - 3 mm beyond this, acting as a solid point to attach the Speedmaster nitro stinger. The stinger mount is drilled to accept the 11/32" tubing, still allowing the stinger shaft to be adjusted for either positive or negative attitude.

Before the stuffing tubes are finally installed I need to work out where the water cooling inlets will be fitted, whether mounted to the sponson aft lower surface or transom mounted.

The Turnigy T20 (Proteus) motors do look very tiny indeed in this hull. Hopefully, the motors will be run with a "Y" winding (730 kv) on either 10s or 12s. Balance (CoG) will be an issue with this hull due the long overhang at the bow and foredeck. I did add epoxy and two-part foam to the tips plus additional carbon fibre around the nose of the hull. The batteries will need to be located aft of the motors to attain a 32-34% CoG. Attaining a 40% CoG for speed runs should not be an issue. Unless parasitic weight is added to the aft end of the hull then I do not believe a 30% CoG to be possible.

[Old School]

I have progressed the drives with the stuffing tubes installed and the 1/4" flex drives cut to length and the cut ends soldered. A downside of the Turnigy T20 cooling jacket is that it is not able to be reversed and be able to positiion the cooling outlet nipple at the high end of the right motor because the inlet nipple would foul on the sponson inner wall. The jacket would need to be drilled and a nipple inserted at the 12 o'clock location. Given the difficulty removing and replacing the jacket without damaging the o-ring I do not wish to go there again.

My son has the stinger drives over 1000 klms away so I based the flexshaft length on the stinger installed on my Osprey build. The flexshafts are contra-rotating and are reduced to 3/16" at the propellor end. I have no idea what suitable props will be required but as I am doing just the basic build my son can research that at a later date.

While I do admire the beautiful all black interiors on the masterful creations of those master builders, I build more for functionality rather than aesthetics so do not pigment the epoxy used. The build has a long way to go yet but hopefully I have made the final task a little simpler for my son.

The view of the transom shows the battle scars this hull has endured in its previous life with the multiple strut drives.

[rol243]

as long as the water outlet on jackets are at the top [ 12 o,clock ] doesn,t matter where the inlets end up. not doing counter rotating props hey ?

[Old School]

Fortunately I was able to rotate the jacket to get the outlet almost at 12 o'clock with the inlet just above the tunnel floor. The left motor is set up with a reverse rotation flex and locking collet.

It is up to my son how he sets up the boat in the future. I believe inward rotating props give better directional stability at the expense of cornering speed. Since my son is a fan of outright speed then cornering speed is not that much an issue.