50" Thunderbolt with twins

[bill34207]

You're welcome Pate. I think 3 mm to the stinger base would probably work out for you. Should help keep the nose down a little better too. At least that's how it's worked on my Falcon single. It rides really well with the strut bottom at 3/8" above the sponson bottoms. Just loose enough to be fun to drive and still doesn't blow over at 70 mph.

[FastVee]

Thanks again Bill, This is a winter build but I started a bit early lol.

Just cut some motor/servo mounts, next I need to decide what bolt pattern to use etc... Maybe 25mm and 30mm 2 of each. (I dont trust that I can make more bolt holes that would match the motor bolt pattern lol ) no cnc here just basic hand tools and I have one motormount that I could use as a guide to drill the holes. http://www.offshoreelectrics.com/pro...od=ose-drmount

Will post pics later of the mounts

[FastVee]

Sorry about the bad pics, misplaced my camera and used my phone.

I could not find thicker then 2.5mm carbon plate anywhere and did not want to use stainless or aluminum plate so I got some cloth and laminating epoxy and thought this cant be to difficult... -well it was not too bad but it is not perfect finish but it will do. (some pinholes in the finish, maybe I will clearcoat them but it is not that really shows anyway when installed to sponson).

This has about 25 layers of carbon cloth.

The 7.5mm thickness should be enough -wanted something strong cause the outrunners are mounted from front so no rear support.
Still needs some filing and sanding to make perfect but not too bad result for first time mount building from the ground up.

Now I need to get the drill and make the mounting holes. -Still thinking if I should install the motors extremely close to the sponson floor or leave enough of space to fit bigger motors someday... but it would raise the cg a bit.

-Pate

edit. 8mm actually forgot to zero the caliper...

[FastVee]

Ok.. just drilled the transoms full of holes.

The sponsons are not 100% even , the left sponson is more "open " then the other one so I installed one stinger first same angle as the ride pad and using alloy"straight angle" managed to get the other one at same angle as the other stinger.

The stingers are quite high from bottom but it should still be ok. (the stinger base is at 3mm but the axles center point is about 11mm from bottom. these are really massive units and it cant be lowered much from this.

The props will be close to ~54mm so this should be ok I hope...

now I need to true the other sponson to match the stinger angle(if that makes sense)


Also got the motor mounts drilled,made the center hole big enough to get coupler throug if needed. 25 and 30mm pattern to match the outrunners I have planned and since the motor also has both 25 and 30mm it will be perfect for them and still will work with bigger motors later on if needed using 2 holes.

The motors will sit higher then needed on these mounts but with any water jacket etc this mount will fit even the biggest motors .

shame the finish is not 100% pretty on the surface but I guess it wont get noticed that much cause the coupler/motor kind of hides the issues...

Will post pics later

[FastVee]

The pics. See the adjustable stingers, left is at the shortest and right is at the longest setting.

The props are 5517/3 propshop ones. (55mm)

As you can see the stingers cant be lowered much so I hope this will work despite the height.(the telescoping stingers makes the propshaft go quite high)

[FastVee]

Just did some calculations...

-The stingers can be lowered 2.7 mm IF no positive angle is needed on the stingers. If some is needed then about 2mm is what can be done.

Since I have not yed drilled the stuffing tube holes should I lower these? <the center of shaft would then be 8.5mm above the bottom of the sponsons -would you guys say that 8.5mm is better then 11mm for the shaft height? -thinking the cavitation would be much bigger problem with 11mm...

(I should have checked b4 I drilled the holes... -that 3mm I was thinking of mounting these abobe the bottom was based prior builds and I forgot these stingers have the bushings quite high cause the telescoping action takes so much room)


-Pate

[FastVee]

I will countiune to talk by my self abit here...

Like I wrote I have never used teflon liner, but since I allready have the tubes and the inner bore of the brass is 8mm w/o the liner and 5/16" brass tube is 7,9mm then in theory I could change the liner to 5/16 brass if I want later .

So I think I will try the teflon. (if you guys dont have anything too bad to say about it)

I just pulled the motors and esc´s out of my other big boat so I can test fit the stuff in this one and check the cg. -and maybe even test drive this before the winter strikes.

-Pate

[FastVee]

I was thinking of better way to secure the lipos then velcro, wanted something good looking and easy to use.

here is what I tried.

First I laminated some carbon cloth to make about 2mm plate, then I took some measurements of 6s lipos and took the rotary tool out(for the carbon not lipo lol) .


The packs will be held using shrink tube(only had tape now, but I have ordered the tubing) and this allows some cog adjustments also.

This is what they look now, should be strong enough and 1 thumbscrew is all that is needed to remove the pack.
The front "slot" is glued with 30 min epoxy and stainless bolts&nuts makes sure it stays in 1 piece even in worst flips.

The trays will be glued in sponsons.

The thumbscrews were only available purple (not really my fav color...) so I removed the anodizing and polished also.

These screws are held with o rings over and under the plate so it wont vibrate loose.

-Pate

[bill34207]

I will countiune to talk by my self abit here...


-Pate

Sometimes you when want to have an intelligent conversation, that's the only way to go.

Looks like you're coming up with some pretty good ideas along the way.
I would try to make the stingers as short as possible. The rudder has much better turning authority when it's behind the props instead of in front of them.

[FastVee]

Haha thats so true Bill!

Actually if the rudder wont work well short I have a plan to make rudder standoff of carbon and I can make it any lenght.

Thinking the stingers should be about 110mm? -I can flip that telescoping bit so I can make it about 100mm if that is not too short...

Ordered the motors, 1250kv and the color is right also with these...
(interior will be all black and silver when I´m done with this build)
SK3-helidrive(5).jpg
http://www.hobbyking.com/hobbyking/s...dProduct=42794

-Thinking outside will have black/HD orange/dark silver paint soon...

-Pate

[FastVee]

Got the primer and black base coat on. Not any major issues with the paint so far, but painting with rattle cans and outdoors is a lottery...(bugs,dust ,rain,wind, cold etc crap) Will wait for few days and mask it off and spray the silver and clear next.

Notice the window groove/frame and the 3 air intake holes are missing...

Ordered some decals also, this boat will be known as FBRacing (fat boy racing) ,since I am not that tiny

Still trying to do the colors I planned from the beginning, black and silver paint and orange decals. Will see how this turns out.

The motors also arrived.


-Pate

[FastVee]

Got the silver and clear on + some of the decals. ALOT of wetsanding and polishing done also.
Still waiting for the orange stripes for separating the silver/black.

Got the servo/esc mount done the servo will be hidden with the esc´s -trying to make this really clean looking so no messy wiring etc.

The transom felt a bit thin so I added 2mm carbon "transom doubler".

Did the "hatch holding nut mounts"(thats a weird sentence lol) ,and used knurled black nylon nuts(looked for these for days...) and stainless bolts to do the hatch holding screw thingys.

Also got the couplers and connectors etc small stuff so soon I can install everything.

So it is starting to look like there is a smallish chance that this will be ready for next summer...

-And the deck without the 3 air vents I removed looks much longer and better now and the filled windshield grooves and modified window design suits this well imo(and it will soon have vinyl frame also) . ,any1 can disagree though.

-Pate

[Chrisg81983]

Looks good some advise is to use silicone when gluing in the lipo system. It will hold up much better than epoxy in a crash. Silicone has survived many 100 plus mph crashes where epoxy did and will keep letting go.

[FastVee]

Hi, funny you mentioned that, I already have good marine grade polymer glue(thicker then reg. silicone and holds better but can be removed and it also flexes some)that I had planned of using. My thought was just using enough so it can be removed since the lipos will be under the deck at least some length the trays would be really hard to remove later if needed and epoxy was used. but great to hear it is also used by others to do the same thing and holds.

[iridebikes247]

Really nice man. The thunderbolt is such a great looking cat and it handles like a way smaller boat too.