1/8th Scale U-95 Hydro.

[785boats]

Our Club is starting up a 1/8th Scale Hydro Class next year, so I thought I'd build the U-95. A fascinating boat with a fascinating story. I built one many years ago powered by a Profi .60 Nitro engine. It was a fast, stable hull, so I thought it should run well as an Electric. The last one was totaly scratch built, but I'm older & lazy now so I bought a kit from ML Boatworks & the cowlings from R/C Boat Company. Both excellent products & service.

The framing kit went together perfectly. Did that last week. After adding the stringers & sanding to shape I added the bottom skin of the main tub last night while my youngest boy's 18th birthday party was happening.:rockon2:
There's a bit of a drop down section in the middle of the tub at the front. I'd be interested to know what the theory is behind it if anyone knows.
I employed my usual method of using cans of drink for weights & squares to hold the bulkheads & frames while the epoxy sets, & then weights to hold the skin down while the epoxy sets.
Here's a few pics of the story so far.

[785boats]

Here's the rest. The thread would only allow me to upload 5 photos in the first post.

[nobbiworld]

Hey Paul, well done. Will be a lot of fun. I have a Dumas Circus Circus hydro in eighth scale waiting for this. See you next Sunday. Steve

[785boats]

Thanks Steve. I'll de there for sure.
I forgot to post a couple of images of the full size boat so here they are. This is what it should look like when it's finished.
8125481255

[siberianhusky]

Very cool! Almost did this one in 1/12 to run on spec power, you're right cool boat that was ahead of it's time.
I ended up doing a Pay N Pak turbine. Took the easy way out, much simpler cowling to build on the Pak. Runs great on a UL-1 motor, just shy of 30" long.
Might have to do this one in 1/10, was looking over the list of framing kits a few hours ago. LOL just dreaming, at the moment I have a backlog of unfinished boats. Winter is for building them, summer is for runnin' & repairin' them.

[JimClark]

Nice Choice that is a great looking hull

[tryinotocrash]

I believe the "drop down" is to help it get up on step better and faster. Nice work so far.

[JimClark]

My guess is clearance for batteries

[785boats]

A cool looking boat indeed Siberianhusky. I too have a few unfinished projects that should have been completed first. But here in sunny Queensland there is no winter. It's boating 52 weeks a year. So time for building is a bit limited.

Jim.
I thought you'd appreciate this one. The drop down certainly allows the batteries to fit more easily, & further forward too.

tryinotocrash
Getting up on the plane faster is more than likely the case with the original boat.

Cheers.
Paul.

[785boats]

Well, I've glued on the bottom & side skins of the sponsons & the side skins of the tub.
Now to seal the inside, then add the foam.
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[Scott T]

Looking good Paul!

[785boats]

Thanks Scott.
Well I've sealed the insides & added the foam. I only put in about 3/4" in the bottom of each section to allow it to grow. After a few hours I pierced each section with a pencil a few times to allow air to get at the foam inside to make sure it was fully cured & wouldn't grow again in the future. It was till a bit moist & sticky in the centre of most of the sections. In some places it then grew out of the pencil holes. Then I cut off the excess above the deck line.
Yesterday (as you saw Scott) while at our clubs race day the hull spent the day sitting on the roof of my car 'baking' in the sun to encourage any more growth. But nothing happened. I pierced the sections again with a pencil & every thing was crisp & dry on the insides of all the sections. There's a few places where the foam didn't grow all the way up to the deck line, so I'll add a bit more there, sand it all to shape & then add the decks.
Here's a couple of pics. The first couple are when it was a bout half expanded, & the last one is with the piercings & the tops cut off.

815888158981590

[cybercrxt]

Looking really good so far! Glad you like the kit. One thing I might suggest is to cut out some of that foam towards the rear of the hull. The weight of it may make it that much harder to get your balance where you want it.

The center pan on the kits is really something I add to help out the FE guys as it gives you extra depth for the batteries we run. Another benefit is the lower angle you have on the bottom pan, the less likely a blowoff will happen. I strive to make 0 degrees on the hulls as much as possible, but certain kits don't allow it. Some of my older designs have more angle too as I just have not had the time to update them, but only a few are left with that issue. Not sure if the U-95 has been majorly modified to be honest. I will have to look at my plans! Mike

[785boats]

Thanks for you insight on the drop section of the centre pan Mike. Much appreciated.
I've laid out the motor & batteries,ESC & some hardware in the hull & it will be tail heavy especially when I add the wing & fins so I'm going to be adding weight anyway. That foam is as light as a feather & I don't think it will account for much. Due to the rules here in OZ, we can't run 2P packs. So it's 1P only. I'll be running it on 8s with this motor
http://shop.rcboatbitz.com.au/index.php?main_page=product_info&cPath=47_45&products_id=782
But I would appreciate it if you could advise me as to where the best COG should be, in relation to the rear of the sponsons.
Cheers.
Paul.

[cybercrxt]

Paul, You are going to find most scales need the CoG around 1-2" behind the sponson heal. Now as I start to incorporate my sport hydro design into future scale kits, that number will be 2-3" behind due to ever increasing stability in what we are finding out with those hulls. Just remember, even if the foam only weights an ounce or so, the counterbalance to counteract that extra weight makes you add a LOT more to the front of the hull to bring it back into check. I use to think it was not a big deal till I really started seeing what the numbers came out to be! Hope this helps, Mike

[jcald2000]

Yep, that lever arm really make a difference.

[785boats]

Yep. I understand about moment arms & lever arms etc & I have to keep that in mind when building the fins & wing. Hopefully the two ply skirts that run down the length of the hull almost to the transom (see photos) will keep more air packed under the hull to help lift the rear end. I'm sure that's the reason for them on the original boat. A bit of positive angle on the wing might help too.
Cheers.
Paul.

[785boats]

I got a bit of time to glue the top skins on over the last couple of days. I used 24hr Araldite around all the edges, frames & stringers, with Shoo Goo on all the foam sections. This gave me plenty of time to get each section lined up & taped down. Then the weights were stragegicallly placed to keep the edges sealed. I should have used 1mm ply instead of 1.5 as there was a lot of resistance to the bending. Unfortunately I didn't tape the rear corner of the second skin down well enough & it lifted. You can see it in the pic. It won't push down with all that epoxy set there. Not sure whether to get a blade in there & cut the glue away & then re glue it , or just fill it & move on. The gap is about 3/32" on the corner. The other corner on the first skin lifted a smidge too, but not that much.
Before I glued the skins on, I epoxied in an extra bit of ply in the rear sections at a slight angle to give some support to the tongues of the fins when they are glued in. I also added some more thickness to the rear of the right sponson to take the turnfin bracket.
Total weight at this point is 2.7kg or 5.7 lbs in American speak. I don't know if that's heavy or light for a bare 42" hydro hull.
Here's some visuals. The decks still need to be trimmed & shaped yet. I'll do that today.
Cheers.
Paul.

[785boats]

I know it's been a while since I've posted anything on this build. That's because, unfortunately, I hadn't done anything on it until a couple of weeks ago.
But in the interim I've built up a 33" rigger, a 26" hydro, an Osprey & a 25" boogieman(for a fellow club member).

Over the last couple of weeks I've fitted & shaped the leading edge of the main hull. Also shaped the fins & wing from some 4mm aircraft ply & fibre glass.
Then I had to trim out the deck of the centre section of the hull with some 1/4" basswood, to take the sub hatch.
Also the cowlings were cut to the shape of the deck. This meant that I had to add some extra decking at the front & rear of the centre section so that the sub hatch didn't extend out past the cowling where it tapered.
The slots at the rear of the hull were cut through the deck to accept the fins & the centre fin has been glued into the cowling. More bracing blocks will be added under the cowling to strengthen it later.

The shaft & tube has just arrived as has the strut. Once I get the motor mount, I'll set all that up.
Should get a bit more done next week during the Christmas holidays.

Here's a few more pics.
Cheers.
Paul.

[Scott T]

Very nice Paul, looks great with the cowl in place.

[785boats]

Thanks Scott.
Still a bit more trimming & fitting to do on the cowls yet. But they are close to being finished.

[cybercrxt]

Looking really good!!! Mike

[785boats]

Thanks Mike.
Feeling too sick to go to work today, so I should get a bit done on the driveline this afternoon.

Paul.

[785boats]

Got a bit done on the drive line set up today

The motor mount that I ordered was too big to fit in the hull so i had to make one from some Aluminium angle. I bent the angle to to what was required & then drilled some 1/4" holes in it the base to give the epoxy a bit more to grab onto. Then I epoxied it into place & added some 1/8th ply braces at the sides. Solid.
The whole drive line & motor is offset to the right 7mm to counteract the prop steer. These boats will still be running the clockwise oval course at our club.
The strut was fitted temporarily to allow the stuffing tube to be bent & cut to shape.
I'm using a 1/4" flex & Speedmaster strut.
I won't glue the tube into place yet as there is still plenty do do on the preparation of the hull & I don't really want the tube in the way.

Here's a couple of pics.
Cheers.
Paul.

[cybercrxt]

Dang, that TP 56 series motor is huge! haha. I have never owned one, so I didn't realize how big in diameter they are! Mike

[785boats]

It was bigger than I thought it would be too Mike. Perhaps I should have stayed with the 40mm size motors.
Just as a matter of interest, & for the guys in our club that haven't decided on a power setup yet, what is a good motor/prop setup to get these 1/8 scale hydros up to competitive speeds?
Come to think of it. What is considered to be a 'competitive' speed?
Cheers.
Paul.

[785boats]

Had a tedious but productive morning.
I finished trimming & fitting the cowls. Then added a 1/4" bulkhead into the rear cowl for strength & for the front cowl to glue to. After that was set I cut away the front of the air intakes creating a recess back to the bulkhead. The spray shields were then cut & epoxied into place. As these will have the hold down locks in them I made them as strong as I could by using the old tongue & slot system, both into the bulkhead & the side of the cowl, to firmly fit them into place.

Now a bit of filling & sanding over the whole boat & she will be ready for paint.

Here's some pics of this mornings fun.

[Richie the shipwright]

In my professional opinion the stepdown at front is obviously so you can hold a bigger esky....... Great work so far man. Love these big girls. I have a triwing u-99 exide 1/8 in carbon/vinylester hanging in the shed unfinished....peer group pressure may force me to drag her out next year and finish her off. So is this boat number 786 for you then mate??

[785boats]

Thanks Richie.
"A bigger esky always results in the best professional opinions".:biggrin: I think that quote deserves to be on a T shirt.
I sincerely hope you do dust off the U-99 & finish it off.
I'm glad to say that I don't have that many boats. Yet!
The '785boats' refers to the old Johnson 785 brushed motor that I use in most of my scale boats, like cabin cruisers, PT boats, destroyers, etc.
Merry Christmas to all.
Paul.

[Scott T]

Coming along nicely Paul, if I ever get a 1/8, I'll send it to your place!

Have a great Christmas mate.

[785boats]

Thanks Scott.
But I've got no where to put it. I've got to sell some boats. There's no room to move in the workshop anymore. And there's precious little room on the workbench to build.
All the best.
Paul.

[785boats]

Well I hope you all had a Merry Christmas. Now it's just the New Years festivities to get through safely.

Last night I did what I'd been dreading every time I thought of it.
I had to cut the nose & the tail off the cowling so they could be fixed to the hull.
Surprisingly, all went well & the resulting joins look OK.

So they were epoxied on to the hull & the underside nose piece was also installed.
Then all the dings, scratches & chips were filled with Auto blade putty and sanded ready for sealing.
Here's a couple of pics.

Cheers.
Paul.

[Scott T]

Thanks Scott.
But I've got no where to put it. I've got to sell some boats. There's no room to move in the workshop anymore. And there's precious little room on the workbench to build.
All the best.
Paul.

That's why we have dining tables and kitchen benches! :smile:

[785boats]

So that's what they're for Scott.
I always had a feeling that it was an urban myth about them being used for food & social gatherings. A whole new world opens up now that you've shown me the light.

[785boats]

Just a quick catchup on the last few days. Not much really.
Firstly, I've given the whole boat a coat of Epoxy sealer.
I've added some 1/32 ply stiffeners to the ends of the cowl sections. Then a tongue was added the front of the cowl to locate it to the fixed section. And then a tongue was added to the rear fixed section to support & locate the rear of the cowl.
A fastener will be needed there, also either side of the air intakes. So I ordered some of these. Nice & streamline & won't spoil the scale look.
http://www.dzusfasteners.net/products/Steel-Buttons-with-springs.html

Then I made up the tail fin brace from some 440 threaded rod, a couple of aircraft clevises and some aliminium tubing over the rod for the bling factor. The brace sits in a slot at the top of the centre fin & will be glued into place after the hull is painted. The clevises are fixed to the transom with screws.

A couple of brackets were made to fix the ends of the wing to the side fins, & the wing is screwed down into the centre fin with 40mm screws. The wing is adjustable to both positive & negative by a few degrees each way.

Old mate Trev at our club gave me a turn fin from a 36" Whiplash kit to try so I made up a bracket for that & temporarily fitted it. Looks about right to me. I'll have to pay him for it when he lets me know the cost.

The only other thing I've done is set up & dry fit the rudder.
Once I set up the servo bracket & servo I can strip it all down & glue in the strut & start painting.

Oops. I just remembered, I'll have to drill the holes for the safety loop & the water outlets first. I hate drilling into a finished painted hull.

So here's a few pics to make it all clear.
Have a safe New Year.
Paul.

[785boats]

Can any one offer a picture of the dashboard or gauge layout for this, or a similar hull, of the era.

I've searched the web to the best of my ability, which is pretty limited, & can't find anything. I've also contacted the Hydroplane & Raceboat Museum. They've helped me out on a couple of things but not this one yet.

Any help would be appreciated.

Cheers.
Paul.

[CornelP]

Try this:

http://www.jalopyjournal.com/forum/showthread.php?t=130864&showall=1

Very long read, but it has images like the one below...

[785boats]

Thanks for that CP.
What a great site.
I've had a quick partial glance through. Some fantastic photos & links on that site. Plenty of shots of the dashboard on vintage wooden boats & shovel nose hydros.
Haven't found anything on the one I'm looking for yet. But I'll keep looking through.

[785boats]

It's been a while since posted anything but that's because I haven't done anything for a few weeks. I hate it when 'real life' gets in the way of building model boats.

Firstly, the Dzus fasteners arrived & they were much bigger than I remember them from years ago. Too big to look right. So I opted for some wooden blocks with a 3/16" nylock nut recessed into the underside & then the blocks recessed into the hull with the splash guards sitting flush. Then a mushroom head bolt was used to fasten the cowlng down. That was for the front. The rear was the same principal but the wooden block was glued to the underside of the rear fixed cowl.

I've also added the 8mm safety loop connectors , as required for racing in Australia.
I'm trying out a set of these.
http://www.espritmodel.com/jeti-afc-anti-spark-connectors-8mm-300a.aspx

The two water outlets have been added & they exit the hull behind the left sponson.

The last thing I've done is to add some foam under the exhaust outlets & carved out the openings. I'll add some fiber glassin there & then carve most of the foam away. The holes will also be blocked off inside the cowl.

The whole thing has also had a couple of coats of primer/filler & sanded back almost ready for paint.

The weather has not been good for painting for a while now. Either too windy, too humid, or too wet (as in floods).

Here's a few pics

[785boats]

Due to some good weather & some time off work I've finally managed to rattle some cans & paint the bottom of this boat. Also did the cowl too.
A guy by the name of Pete at the Hydroplane & Raceboat Museum sent me over a pic of the original dashboard. Love it.
I've also found a driver to replicate Leif Borgensen.
More painting today if the wind stays down.

Happy Easter.
Paul.

[785boats]

Just finished the paint on the top deck . Came out all right.

I forgot to say in the previous post that my sister created some decals of the dashboard for me.
Here's some pics.

[Hydro111]

Looking great Paul, can't wait to see it run.

[nobbiworld]

Paul, looking good. I have been painting my U-4 and Artie's shovel today. Both are looking good for a run in mid May. Will be great fun and quite a spectial on our track. Steve

[785boats]

Thanks guys.

I can't wait either Chris.

There's quite a fleet now Steve. At least 6 that I can think of.
I've got this week off & I'm aiming to have it on the water at this Sundays' practice day. Hopefully. All depends on how far I get with the detailing.

[Scott T]

Coming along really nicely Paul!!

What type of paint did you use? The finish looks quite good.

[785boats]

Thanks Scott.
Yep, it came out pretty good.
It is 'White Night' rust guard epoxy enamel. In a rattle can. You don't even need a primer for it. Although I already had sealed & primed it. Just a light dust coat & then a full wet coat about 5 minutes later. No sanding takes 6 hours to touch dry though & 16 hours for re coat.
But the finish on this first coat is good enough to leave.
Just got to make sure that the trim colours don't attack it. The ones I've got are acrylic so I can't use them. I'll have to get some enamels.
Cheers.
Paul.

[Richie the shipwright]

Beautiful work paul! What power systems can we use in 1/8 scale here in oz...?
Btw... I dusted off my 94 Exide hull... looks heaps faster without cobwebs!. :-)

[785boats]

Thanks Richie.
Yep. I've got a few boats covered in cobwebs & they do look awfully slow in that state.
I think most guys are running 10s Some run 12s I think. Not sure on the rules. But I'm running 8s in this one. Mainly because it's a bit smaller, & hopefully lighter, than most at only 42". Also, I've got lots of 4s packs but no 5s.
Cheers.
Paul.

[Richie the shipwright]

Mines a bit porky... i was originally building it for nitro. Its a 45" all vinylester carbon/glass build. 4.5kg bare hull. Ill do a build thread when i finish my current project. (soa)

1/8 scale is not really raced anymore here in sa, hopefully one day soon things will change... its so great that you guys have a few on the build, be awsome to see em all let loose at once...

[785boats]

It certainly will be good to see them on the water together.
I'll have to weigh mine again now that the bits & pieces have been added & the paint is mostly done. It's still drying after todays' little effort.
A build thread on the Exide would be great.

Well over the last few days I've been adding some detail in the form of numbers, Air Force decals, dashboard & paint to the hull. The fins & the cowling around the exhausts were given a coat of grey.I think I picked a grey that was too dark in hindsight, but it's going to stay as it is.
Then the exhaust ports were given a coat of Aluminium.
Next, it was the job of masking up the whole boat for the red & orange stripes. The whole stripe was painted red & allowed to dry. The rear wing was done at the same time.
Not being a painter, the only way I could think of getting the red/orange blend line was to make a cardboard template & fix it down the middle of the stripe held up off the hull about 1/4". This was so the orange half would have a soft blend line like the original.
Well it seemed to work but the first one I did I ended up with the orange too wide. :sad: So I repainted it red & did it again. Much better. :biggrin:
The other stripe came out alright the first time, much to my relief. Neither of them are perfect, but like I said I'm no painter.
I still have the blue stripe over the cowl & down the sides to do yet & then it's the clearcoat.
Here's a few pics.
Cheers.
Paul.

[785boats]

Woohoo!!!I managed to get hold of a mobile auto pin striping guy & he came around & gave me a few meters of 12mm blue stripe for just a few bucks.
Man that saved a lot of masking & painting.
Just finished it & here's the results. Sets it off nicely.
A few more decals to get yet & then the clear coat.
Won't be ready for Sunday as I'd hoped though.

[JimClark]

Looks great can't wait to see it on the water

[785boats]

Thanks Jim.
Neither can I. It gets a bit closer each day.

[Scott T]

Looking great!! Can't wait to see it hit the water sometime soon.

[785boats]

It's been a long time coming but she finally got wet.
Over the last couple of weekends we've been testing her in less than ideal conditions. Windy & Choppy. Haven't been able to open her up in the straights yet.
Might need to drop the strut a tad because she 'feels' a bit light in the front into the wind.

Here's a video.
The pic is of Damien retrieving it for me after its first run.


http://www.youtube.com/watch?v=oyxuUZSCsTk&feature=c4-overview&list=UUmckFCp5vHpw83p9Hn-l1hg

[785boats]

Here's a video of the ol' girl at Sippy Downs last weekend.
Many thanks to Dave at Joker R/C Productions.

https://www.youtube.com/watch?v=421v9hx7_lM

[cybercrxt]

Sweet Camara work, and great looking hull Paul! I am definitely gonna have to get that video on the website! Mike

[ron1950]

your right mike id sware that is the real boat there if it had jet noise lol

[cybercrxt]

haha, very true!

[785boats]

Thanks chaps.
Yep Dave does some great videos. If you are into Off road R/c check out some of his Videos down the side bar of the link above. Anything with "Joker RC" in the title is his.

Here's a bit of a taste.
https://www.youtube.com/watch?v=8LdjSoH7sAI&list=UUqSyxHvF32NWzjXhV7SQsYA

https://www.youtube.com/watch?v=lW5JWt0thtw

Bear in mind, he drives the cars while he films them.

Cheers.