Bluebird k-7

By jumpugly 21 entries 3 Jun 2025 — 16 May 2026
216Likes
93Comments
Chapter 01 / 21

21 chapters · Page 1 of 3

jumpugly Opening post 7

Bluebird k-7

Hello all! Before my two week sojourn out to California starting tomorrow...

Here she is, all 31 inches and 4.8 pounds of 3D printed 1/10th scale madness. And the questions are starting arise after more than a few hours spent in research. How to get her to plane even close to scale?
1) EDF? Probably not, actually I don't think even a 90mm fan, (which will, in fact, push a faomy jet) will ever get this boat to plane.
2) Prop? Maybe with dual 6s and a killer motor, monster cooling etc. But, nowhere near scale with a big prop hanging out the back.
3) Turbine? probably yes, but way out of my league in mechanicals and $$. There will be tons of head-scratching my quickly balding head on this experiment.

This is going to go on the shelf for the long haul as my freighter needs finishing and the big Sterling Chris Craft Corvette is screaming at me. But, off to Cali for now...I will drop some pix from time to time of our travels.

Best to all!
👍😉😊
Liked by peterd and EdW and

Like a gargoyle...

There she sits staring at me like a gargoyle from some old cathedral parapet. Too much to do and not enough time, but have started experimenting with plastic epoxies to best hold the sponsons in place, I am not sure exactly which adhesives will work best on 3D printed plastics in such a large scale. But, so far a fast setting 2 part seems to work well; JB or Devcon are about equal.
I've also shelved the idea of a ducted fan moving this beast; which is almost exactly 5 pounds empty. So, I stumbled upon an old Traxxas Spartan for parts; meaning hi-performance lipo set-up with water-cooled brushless etc. which I will try to modify even further. It will take more than a bit of bashing to marry the Traxxas mechanicals into this beast.
For now she sits and stares balefully at me. To placate the beast (and Donald) I will try to set her up for a float test. That's if she will even float at all!
A crucifix and garlic to hold off the monster may be in the offing!
Just kidding.
More to follow, albeit in drips and drabs.
😉
Liked by GaryLC and Commodore-H and

Frankenstein!

Colin Clive here with a general update!

I managed to find partially destroyed Traxxas Spartan that had 50mph speeds and managed to salvage (or rescue from the grave 😂) the water-cooled brushless motor, drivetrain, and water-cooked ESC, plus the rudder and associated controls.

It looks like they may just fit as an r/c jet turbine is way beyond my means as I my wife and I just managed to clear up our girl’s graduate school loans before the jack-booted masked men show up this month, as threatened, and demand that we pay up or else. The nice loan guys are now gone…sadly.

So, as I can’t play nice with this monster and give it the Rolls Royce
treatment, it’s prop drive for now.

Hopefully, I can scream, “it’s alive!” someday this year!
😂
Liked by BOATSHED and peterd and

Good Lord it FLOATS!!!

Well, that's one hurdle down. Now the butchery begins to figure out a way to add the Traxxas guts.
😂
Liked by Commodore-H and Len1 and

Follow-up

As for butchery...After an all-nighter I managed to cut, chisel, sand, hammer out enough of an engine bay for the Traxxas Spartan guts. Working with 3D plastics is not for the faint hearted and I made a promise to myself never to embark on such a venture again. Be that as it may, I'm in too deep to quit now. There is so much more to fabricate to help this power plant from vibrating itself and the boat all to hell.
More to follow.
😉
Liked by Len1 and RNinMunich and

Paint color success!

Dave at the Bluebird Supporters Club was kind enough to share the correct color used on the real Bluebird restoration. It is (now) called Azure Blue code # 5009. Now the trick is getting a sample or a color card. I don’t think a can of spray paint can be shipped across the Atlantic. Suggestions appreciated! I guess I can contact MBP.
😉
Liked by SimpleSailor and EdW and

Paint and Micro Balloons

Hey there gang and a huge thanks to Doug as I went to my local auto-paint store and the whipped up a rattle can of RAL 5009 Azure Blue Spray Paint. As mentioned the Bluebird Supporters Club used that color in the actual K7 restoration. I ran a this group of tests (my usual obsession) on three different primers and had good results all-around with a grey automotive primer giving me a nice even result.

Also, I've been fighting with the large joins on this printing and have gone to a two-part Z-Poxy finishing resin mixed 3:1 with Deluxe Products "Micro Balloons." This worked better than expected in filling joint seams as it sped-up the drying time of the resin from 24 hours to under an hour. It makes a great workable paste and sands much better than this horrific heavy 3D plastic.

It's still early, but onwards and upwards!
👍😉
Liked by jbkiwi and hermank and

More Bashing

Dr. Frankenstein here. Most of the Spartan transom has been implanted into the K-7 with as much 10 ton epoxy and micro balloons I could mix up quickly. The drive shaft and rudder (minus the plumbing and servo arm) are trial fitted for a leak test tomorrow.

I really don't love all this hardware, but have no choice right now as the Spartan set-up is more likely to get this (now) 7 pound beast to move at any appreciable speed than any size ducted fan could do...and as you know I can't justify the cost of the whole turbine thing. Maybe someday...if I can go this far I can go back to a more scaled out business end. Ernie Lazenby's K7 is still my inspiration.

Updates to follow and forgive the mess!
😉
Liked by jbkiwi and Len1 and

Ballast and leak check...

Well, back at my bosses' pool and she passed the ballast test, but is taking on water. I will have to remove the drive train and do a large tub test with some sort of dye to find the exact spot. I have some ideas, but no proof.
A complete base coat of automotive primer may be of assistance as I cannot see the hull joins as much as I'd like too. My epoxy and Micro Balloon concoctions are too similar in color to the printer plastic.

Much more to do. 🙄

ps: The Traxxas hardware, while unsightly, will produce a sizable rooster-tail some day. I hope.
😂
Liked by Mike Stoney and jbkiwi and

Not the bosses’ pool

Stripped her down and found the leak… I hope. It’s not the prettiest location, but the driveway works as well as pool...well not quite.
But, I was getting desperate to find a way to shore her up.
👍🏻😉😁
Liked by jbkiwi and JOHN and

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