HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Feb 03, 2011, 11:37 AM
Registered User
Farnham Common, UK
Joined Oct 2009
247 Posts
Build Log
Touchwood Bluebird K7

Hi all!

Having just completed the Billings Slo-mo-shun (build log on the scale boats forum), my new project is the conversion of the Touchwood 1/12th scale kit of Bluebird K7 to radio control powered by a brushless electric motor.

The kit consists of a GRP hull and sponsons with other components made of resin. The challenge is to reduce the weight as far as possible which means binning most if not all of the resin parts. I will base my conversion closely on the successful experience of George Thomson a model builder in Scotland who has been kind enough to give me a lot of detailed advice. You can see in the U-tube clip that his Bluebird goes like the wind so, if mine doesn't it will be down to poor construction and not bad design.

brushless bluebird K7 G Thomson (3 min 16 sec)


The drive system for the boat will be a brushless 2750 kv motor with a 70 amp water cooled E.S.C.

I have started with the sponsons and binned the heavy resin planing wedges supplied with the kit. I filled most of each sponson with expanded polystyrene and inserted a planing wedge made of balsa wood. This is then skinned in thin plasticard (styrene) as are the forward and trailing sections of the sponson. The width of the sponsons is 1 inch but I have angled the planing surface out to 1.4 inches at the rear - this may be more than is needed but it will be easy to cut it back if required.

That's it for now but I will keep adding to the log as the build progresses. Comments and advice along the way would be gratefully received.

I have to decide whether to use a rigid propellor shaft as George did or whether to use a flexi shaft which may be easier to fit. Any thoughts on this?

Jeremy
JeremyBB is offline Find More Posts by JeremyBB
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 03, 2011, 12:07 PM
Registered User
rotorkilla's Avatar
Stoke-on-Trent, UK
Joined Nov 2010
1,113 Posts
Looks like a nice piece of kit, the one in the Youtube vid seems to run well but i think you could get more speed out of it still

The Bluebird K7 is a hydro, one of the fastest hulls ever designed you should be able to get good results.

Nice project, keep us informed

BTW i'd say flexi shaft, www.Astecmodels.co.uk should do what you need
rotorkilla is offline Find More Posts by rotorkilla
Reply With Quote
Old Feb 03, 2011, 02:52 PM
RELAX. You'll live longer
785boats's Avatar
Brisbane- Australia
Joined Jul 2007
3,289 Posts
Hi Jeremy.
Now you've got me inspired to get stuck back into mine. I started a scratch built 1/8 scale version some time ago & it's just been sitting on the shelf in bits for too long.
I'll be watching yours with interest.
Here's where I got to with mine.
http://www.rcgroups.com/forums/showthread.php?t=1106122
Cheers.
Paul.
785boats is offline Find More Posts by 785boats
Reply With Quote
Old Feb 03, 2011, 03:29 PM
Registered User
ooyah's Avatar
GLASGOW
Joined Feb 2011
306 Posts
Touchwood K7

Quote:
Originally Posted by rotorkilla View Post
Looks like a nice piece of kit, the one in the Youtube vid seems to run well but i think you could get more speed out of it still

The Bluebird K7 is a hydro, one of the fastest hulls ever designed you should be able to get good results.

Nice project, keep us informed

BTW i'd say flexi shaft, www.Astecmodels.co.uk should do what you need
rotorkiller,

This is my first posting just joined.
I am the builder of the K7 and in the you-tube video the boat is cracking on at 35 mph on a windy day, if you look at the 3 pass L>R you will see it nearly taking off.
Yes you can make it go faster by using LIPO's I use Nimh 8.4v x 4300mamp. but you must remember it's a straight runner and will not turn at speed.
I am a member of Glasgow Richmond boat club and on our lake I can only get a 8 sec run.
I live near Loch Lomond and on a flat calm day I can send it as far as I can see it to my right and then run it past me until nearly out of site and BOY does it fly, so to get the best out of it you need plenty of water. This was my first attempt at an electric boat as steam engine building has been my passion.
George.
ooyah is offline Find More Posts by ooyah
Last edited by ooyah; Feb 03, 2011 at 03:30 PM. Reason: adding
Reply With Quote
Old Feb 12, 2011, 04:24 PM
I SEE NO SHIPS
dunc2504's Avatar
Somerset England
Joined Feb 2007
1,234 Posts
Nice !
I have been building Torchwood's Bluebird K4 over on the scale forum.
Nearly ready to run now.
Dunc2504
dunc2504 is offline Find More Posts by dunc2504
Reply With Quote
Old Feb 16, 2011, 10:29 AM
Registered User
Farnham Common, UK
Joined Oct 2009
247 Posts
The main structure of Bluebird K7 now complete. The sponsons will be removed for painting before gluing in place.

I have closely followed OOYAH2's example. Specifically
1. Sponsons attached using 2/5ths inch alu tube. Fairings over the tubes will be made from balsa and thin marine ply - much lighter than Touchwood's resin parts.
2. Distance between the inside faces of the sponsons is 8 inches. The tops of the sponsons are parallel to the water line and the planing points are 3/4 inch below the water line.
3. The tail fin is made of 1/32nd marine ply on a balsa frame - again much lighter than the resin fin supplied.
4. Access to the hardware will be through the removable centre section of the engine cover. The front and rear sections will be glued in place once the hardware is installed. 1/4 inch lips will be added to the inside faces of the front and rear sections to help keep water out. The centre section will be secured with waterproof tape when running, although I will look at an alternative using Velcro.
5. I have cut out the air intakes and put a plasticard former behind which will be glued to the hull along it's bottom edge - currently white, it will be black when finished and hopefully create the impression that the air intakes go somewhere.

So far, so good. The difficult bits are yet to come...

Hi Dunc2504
I've been watching your build but could never even dream of achieving your quality of finish. I look forward to seeing how it goes.
JeremyBB is offline Find More Posts by JeremyBB
Reply With Quote
Old Feb 16, 2011, 12:59 PM
Registered User
ooyah's Avatar
GLASGOW
Joined Feb 2011
306 Posts
Bluebird K7

Hi Jeremy,
Your build is coming along nicely and the air intakes look much better than mine . As you can see K7 at 35 mph is right out of the water.
As I said this project was a diversion from my Flash Steam exploits as OOYAH was getting too fast and it only needed a radio glich at 40 mph to create a disaster, the boat is in moth balls until I decide what to do with it.
I have just completed a D10 with reversing gear for my tug CERVIA so I am trying to get the engine shoe horned into the boat for the summer season.
Here is my first try at posting pics of K7, and my flash steamer OOYAH at 40 mph on the last pic this is what happens with a radio glich--hard left --hard right and then hard left to straighten up, quite frightening.
George.
ooyah is offline Find More Posts by ooyah
Reply With Quote
Old Feb 16, 2011, 01:04 PM
Registered User
ooyah's Avatar
GLASGOW
Joined Feb 2011
306 Posts
Bluebird K7

Hi Jeremy,
Your build is coming along nicely and the air intakes look much better than mine .
As I said this project was a diversion from my Flash Steam exploits as OOYAH was getting too fast and it only needed a radio glich at 40 mph to create a disaster, the boat is in moth balls until I decide what to do with it.
I have just completed a D10 with reversing gear for my tug CERVIA so I am trying to get the engine shoe horned into the boat for the summer season.
Here is my first try at posting pics of K7.
George.
ooyah is offline Find More Posts by ooyah
Reply With Quote
Old Feb 17, 2011, 03:19 AM
I SEE NO SHIPS
dunc2504's Avatar
Somerset England
Joined Feb 2007
1,234 Posts
Hi.
That build is going great !
The boat is going to look very nice for sure.
George , that picture of K7 on the plane is fantastic , well done sir !
I am going to have to get some pictures of my K4 at speed this summer .
I am just finishing the detailing of my third Speedline 1/24 scale K7 with brushless power, so I think a touchwood could be next (if I ever get time to finish my steam projects )
Dunc2504
dunc2504 is offline Find More Posts by dunc2504
Reply With Quote
Old Feb 17, 2011, 11:46 AM
Registered User
ooyah's Avatar
GLASGOW
Joined Feb 2011
306 Posts
Hi DUNC,
I have been building engines since I retired 12 years ago and have done some experimentation with Flash Steam, the boat that is shown below the K7 is a Flash steam powered boat at 40 mph.
The engine is a copy of R Kirtley's Flash steam record holder around the pole at 120 mph.
What is your interest in steam ?
Now that I have mastered posting pics would you like to see some of the Flash Steam engine build ?

George.
ooyah is offline Find More Posts by ooyah
Reply With Quote
Old Feb 17, 2011, 03:35 PM
I SEE NO SHIPS
dunc2504's Avatar
Somerset England
Joined Feb 2007
1,234 Posts
Hi.
I build slow launch type stuff over on the steam boats forum. When I want to go fast , I tend to go for brushless electric . that is something to do with fear of flash steam .
Posts on your flash steam projects would be of great intrest to me and the other guys on that forum for sure.
Dunc2504
dunc2504 is offline Find More Posts by dunc2504
Reply With Quote
Old Feb 28, 2011, 12:22 PM
Registered User
Farnham Common, UK
Joined Oct 2009
247 Posts
Hull now painted so it's beginning to look more like the real thing. If my pics look suspiciously like OOYAH's, that's because I am basically copying his approach. When the paint is completely dry, I will follow Touchwood's recommendation and buff it up to a shine with T-cut.

Cockpit occupied by one of Pete's pilots, painted mainly in pale blue to replicate the overalls worn by Donald Campbell. Canopy not yet fixed in place. I have run a half circle section of electrical flex insulation along the front of the cocpit cut-out and will use clear silicone to create a seal between this and the front of the canopy. I have used the resin canopy runners and instrument panel from the kit but have ditched the heavy resin seat in favour of one made of polystyrene foam. I have also used the resin transom and jet pipe surround cutting off the section which would have required making a hole in the aft end of the hull. The jet pipe will be formed from aluminium sheet and will sit recessed into jet pipe surround.

Next job will be to make the fairings over the sponson arms with balsa covered in 1mm ply sheet. And then on to the installation of the hardware which will be a lot more challenging.

Hi Paul (785 boats) - I look forward to seeing progress on your 1/8th inch scratchbuild K7. It will be awesome when finished.

Cheers!

Jeremy
JeremyBB is offline Find More Posts by JeremyBB
Reply With Quote
Old Mar 11, 2011, 12:57 PM
Registered User
Farnham Common, UK
Joined Oct 2009
247 Posts
The aluminium tube connecting the sponsons to the hull now encased in fairings made of balsa and ply. Now on to installation of the hardware. That's where the fun begins!
JeremyBB is offline Find More Posts by JeremyBB
Reply With Quote
Old Mar 11, 2011, 01:16 PM
RELAX. You'll live longer
785boats's Avatar
Brisbane- Australia
Joined Jul 2007
3,289 Posts
Looking really good Jeremy.
Those pics give me a great layout of all the rivets I'll have to simulate on mine when I finally get back to it.
I always enjoy the process of installing all the hardware & drive line.
Do the instructions give a COG point for a surface drive setup? I know where the one is for the Jet drive, but I'm not sure for the surface drive setup.
Cheers.
Paul.
785boats is offline Find More Posts by 785boats
Reply With Quote
Old Mar 12, 2011, 10:06 AM
Registered User
Farnham Common, UK
Joined Oct 2009
247 Posts
Hi Paul

The photo of a full sized K7 mock-up shows up the rivets better than on my model, particularly in the outriggers for the sponsons which on my model will be rivet free.

I don't know about the COG as there are no instructions for the RC conversion. I believe that the model should float level in the water when not under power. I will adjust the fore/aft position of the batteries to trim as necessary - trial and error. OOYAH may be able to give you a better answer as his model is up and running.

Cheers

Jeremy
JeremyBB is offline Find More Posts by JeremyBB
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion K7 Bluebird drawings. 785boats Dock Talk 27 Jul 31, 2012 02:03 PM
Cool Bluebird K7 bluebell Scale Boats 4 Jan 12, 2009 12:18 PM
Build Log Speedline BLUEBIRD K7 dunc2504 Scale Boats 4 Nov 29, 2008 05:09 PM
Plans for K7 Bluebird Symmbian Racing Boats - Electric 9 Oct 18, 2006 03:37 PM