Hey me hearties! Stuart Delf at Touchwood was kind enough to send along a nice reply to my query.
He has not produced a K-7 in two years and has no plans to do so in the future. He suggests eBay searches as my/our only outlet.
Bummer!
However, I appreciated Stuart’s reply.

hi there

A Plan for a Jet X powered semi scale Bluebird is available from a Company located in Canada who may be producing the plans.

Next picture Don Walkenshaw's gas turbine driven Bluebird K7 - early version.

john

Shucks🤔
Just cancelled my Jetex order.
Found exactly the same parts (same pictures) for ca £39.52 instead of £99.00.😮
Now cooled off on the whole idea.
Ciao, Doug😎

Doug, no luck yet with Stuart. But, have to love those Jetex pix!!!
Commodore! The jet turbine idea is a great one, but you'd have to pony-up mucho $$$. A cheap one on Ali is $750. Yikes!

BTW: here's an r/c ready 1/8th scale Bluebird made by Gia Nhein aka: woodenmodelships.net in Vietnam . I've inquired about price on a lark. We'll see.

Good luck with Stuart Jump, keep us informed please.
Doug😎

"effects of connecting aluminum electrolytics backwards"
More memories brought back RP.
We used to fire them, like mini mortars, over the partition between our test dept. to the girls in the production dept. at the other end of the room😁They create wonderful snowstorm effects as well.😂🤣😆

Back to Jetex.
Shame the Jetex forum fuel discussion seemed to fizzle out (damp fuse?☹️) and vanish in the desert. Made me curious though so hunted around a bit.
Have just ordered from Eb a complete Jetex 50, but more importantly, a box of 15 Sebel pellets with gauses and washers etc.😉 Wish me luck🤞💥😭
Cheers, Doug😎

Bluebird K7, very cool I'd like to see someone do it with a real turbine

Interesting discussion here on formulating the Jetex propellant in the Mojave desert:

However, guanidine nitrate CH6N4O3 (GN)?
Birdsh*t? Really? I guess why not, the crystals make really good gunpowder. As a youngster, I'm surprised that I didn't blow my fingers off and lose my eyesight. Very Darwinian. I used to build plastic boats, fill them with 4" cannon crackers, push them off and ... BOOM. My neighbour called the cops one night. I almost killed his cedar. He threatened to tell my dad.
I became a responsible citizen, joined the airforce, became an engineer and taught EEE and physics for almost 40 years.

However, I never really got over blowing things up and loved demonstrating to first year EEE students the effects of connecting aluminum electrolytics backwards and why we wear safety glasses in the lab.

https://www.jetex.org/index.php/jetex-forum?view=topic&catid=8&id=4

Doug!
Thanks for this, I'll give Stuart a try!
😊

Hi JP, herewith some clarification!
Try contacting Stuart. Maybe he still does one off special orders.🤞
Cheers, Doug😎

https://www.touchwoodmodels.com/

Hi Ed!
My 1/12th scale Touchwood K-7 was a very early version made of a casting resin that weighed a ton and didn’t seem suited for rc at all to me, but I do believe that later incarnations were of a lighter material and the hulls were bored out more properly for r/c equipment and motors, and (most importantly) the sponsons were lighter (hollow maybe?). My sponsons were solid and were like bricks!
😉
However, it was awesome in the museum scale department, with rivets and panel lines, and made a beautiful display piece. It broke my heart that it melted to a lump under it's Lexan case in my shop in our horrible house fire. Oddly enough another Lexan case with a 1/8th scale Lotus 72D in it melted too, but lifted off the kit and the car was still pristine; go figure. I guess the spirit of Colin Chapman was watching over that one.

It's a shame that Touchwood seems to have packed it in. Some folks in the hobby press said it was a Brexit thing, but I can't attest to that.
However, I think old Touchwoods can be had in the large scale, but they are now made to order (if at all) and are quite pricey; just not sure. Clarification on these points is appreciated gentlemen.

Which scale did you pick up Ed? Also, send Pix!
👍😉

I’ve got an unbuilt Touchwood Bluebird that I am planning to build with a conventional prop. I have got an article from Model Boats Magazine that covers the build.

Never had Jetex but I had a bottle rocket powered free flight glider….it hit a tree…🤣

Oh Man!
That brings back memories RP👍
I still have my Jetex 50 somewhere (🙄), but where to get the fuel pellets today?☹️
I used it in the '60s to power a Kiel Kraft Hawker Hunter, which eventually crashed and burned😭One of the reasons I turned to model ship building and built my 1/72nd scale H class destroyer Hotspur. As built shown in pic 1 on her maiden in Radnor Park, Folkestone ca 1966.
Pic 2: refitted with RC some 20 years later, alongside Type 1A U 26 to same scale.
Both still 'seaworthy'😊
Cheers All, Doug😎

Great stuff RP! Ah, those were the days I’m sure. Thank you for sharing these!
But, honestly where can we find asbestos paper these days?!
😉😊

As a youngster living in Lee-on-the-Solent, Hampshire and a Navy Dad working at the Admiralty I received a copy of the Eagle book of Balsa Models which coincided with Campbell's Bluebell trials in Scotland. Inside were directions for the construction of a Jetex powered surface skimmer which I promptly built and powered across the boating pond in Gosport. Scans:

And Cobb's Crusader to boot! Great stuff John!
Thanks so much for these posts and vids they are very helpful and eye-opening at the same time. I can't help but think that the Crusader would be a much more difficult tune and trim out considering it's aft heavy design. Although I suspect Reid Railton would get aggravated with me!
However, once you've got it tweaked just right I'm sure it will fly.
After all, Mr. Cobb did get it to go over 200mph.
The cg, and weight to EDF thrust ratio seems to be the rub. If I do decide to jump in with both feet or sponsons, as it were, tackling these issues will be key. I just hope I've got your guts and patience.
😁😉

Hi there

I think the maximum speed I would be able to achieve with this model of Bluebird would be possibly 45 to 50 mph that would really be stretching it.

Long story - but I don't fancy the idea of taking more yachts out at the lakeside 😊😮

For the novice; the basic principal of a ducted fan is a propeller in a tube - what volume of air & speed is pushed out at the back end. It is not increased in volume - it is just whatever goes in the front - comes out at the back - at the same volume and speed.

Unlike a jet engine - where the air is expanded in a gas form and accelerated at a greater speed.

Therefore, with a ducted fan, your critical factor is the power to weight ratio, so, the all up weight of my model Bluebird is just over 4 llb and that is with the batteries in the model. The thrust of the ducted fan is roughly about 6 - 7 llb. Giving a ratio of about 1.75 llb.

To get more speed, I would somehow have to drop the weight of the vessel, or, increase the thrust.

If you want a good headache, my next model which I am in the process of testing further is John Cobb's Crusader (1955). This has 100 mm ducted fan and is a running on 44 volts. It refuses to plane properly - when she starts off she creates such a spray it sucks a lot of water into the fan and therefore flooding the model.

I have sent off for lighter batteries and I am thinking about repositioning the centre of gravity & all sorts. Later this year I think for retesting.

John

I think in 1/8th scale your K-7's scale speed would be close to 60mph (96.5 kph)? Although I forget how the formula is calculated exactly. So I completely understand the need for a bigger lake!
😉

My model is 1/8 scale - and the ducted fan is 80 diameter - with 12 blades. Running on 2 voltages for testing - the first was run on 14.8 batteries just to find out the characteristics of how she handled. Then when I was happy and ironed out a few faults, I upgraded the batteries up to 11.1 giving a total voltage of 22.2 volts. Now all I need is a BIGGER lake, to allow the model to achieve its top speed. As I was having to throttle it down 1/3 of the way down the length of the lake cos she ran on 'no power' for a good distance.

I am very envious of you i to love the blue bird does he make and sell or is it a one of because I would love one
Philuk👍

This is great John! What scale is your K-7?

new vid of Bluebird K7

JOHN

John!
Thank you so much for sharing your thoughts and video!
I, for one, am skeptical about my ability to make a 3d printed Bluebird work. I feel prop driven would be an easier way to go, but not as rewarding.
CG, balance, weight distribution seems like a huge deal and I love that you got it to work. Certainly no mean feat. And to get it to plane! Wow! The inspiration is certainly appreciated.
👍😊

hi there

a ducted fan driven Bluebird is not a simple matter - I myself spent a good few years doing a lot of research -collecting plans and data from all over the place. Any person who is confessing to have built or is building an exact scale of Bluebird K7 to be driven by a ducted fan - I myself would be very sceptical. The reason I come up with this statement is I have done it myself and built the model. My model is pretty successful. My model is driven by a 80 mm ducted fan and I think it was 2 x 6S lipo batteries. The model is made basically from very lite ply and balsa wood. I had to think of a way to increase the flow of air into the ducted fan as on the model the canopy (if it is solid) will restrict airflow (only on a ducted fan and not gas turbine).

The way I worked around it, the canopy is of a mesh, and under the canopy is a hollow tube which runs to the fan and either side of the canopy there is an opening in the deck to allow more airflow.

The model I built achieved approximately 37 - 38 mph. However, the size of the lake restricted me from keeping the power on. I do have a couple of photographs which I will put on.

Also, if you go onto my 'harbour' have a look at the short video and couple of pictures of the build which I put on Mayhem.

There are a set of plans for her which are available on the web also, you may be able to obtain a set of plans from the Bluebird Society which is in the Lake District (Ruskin museum).

john

Hey Cash!
I asked the printer/builder for weights and measures and will use that info for research.
It'll be a long trip down my usual modeling rabbit hole.
😉😂

All kidding aside Jump, before you decide to pull the trigger on this, do some searches on RCG and Google, and this site too, on EDF hydroplanes. You also might look at the aircraft EDF section too, to give you ideas. Does the kit list any specs on the EDF diameter or power? THAT would be helpful.
Cash

little voice in your ear.............DO IT!!! GIVE THE GUY SOME MONEY!!!😂