1:35 Schnellboot S-131

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1:35 Schnellboot S-131

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5 January 2010 at 23:09 #24874
Roel
Participant
@roel
Good evening.

I’m Roel, living in a small village in Holland.

One year ago I started building the type S100 Schnellboot (called E-boat by the Allies).

I equipped her with 3 Speed 400 motors, the outboard motors propelling two 3-blade 25mm props from Dean’s Marine on 7,2V, the middle motor propelling a 32mm 2-blade Graupner speed prop on 9,6V.

The inboardmotor has its own ESC, the outboardmotors share another.

The two “Effect-rudders” are mixed with a V-mixer to achieve the “Lürssen-Effekt”, wich was a technical innovation on the S-boats.

The centreline rudder has its own servo, but, when the “Effect-rudders” are engaged to port or starboard, the centreline-rudder goes with them.

The craft is fast and agile.

When on full speed and making a sharp turn, the hull goes nearly 45 degrees aside.

Its funny to see that the “Lürssen-effekt” works on scale too! The bow goes down and she rides more flat on the water. If she is faster, I don’t know, can’t measure that. And on the real thing the difference in speed was only about 1 or 1,5 knots… In 1:35 scale difficult to see!

I placed a movie of her on youtube:

http://www.youtube.com/watch?v=1Di11LuII1k

The next Schnellboot is under construction:

She will be equipped with tho BL-motors (Port & starboard) for attackspeed and a Speed 400 on the centreline for cruisingspeed.

That’s because I noticed the rudders are not so effective when the centrelinemotor isn’t working.

So I worked the other way around as with the S-131.

The new boat will be equipped with a movable 20mm gun in the bow and a soundmodule with dieselsound. No opening torpedodoors, as with some of our German Modelfriends… That was too fiddly for me!

In Holland we have also a Modelforum, (“Het Modelbouwforum”) together with planes, cars and so on.

There is a very lange amound of talking and foto’s of the S-100 from Italeri in this threat:

http://www.modelbouwforum.nl/forums/bouwverslagen-schepen/72708-bouwverslag-8ste-schnellboot-flottille-italeri-1-35-a.html

Some of the Dutch S-Boot builders on the “Modelbouwforum” organised themselves in the “8th (RC) Schnellbootflottlle” with their own fanion:

http://img201.imageshack.us/img201/826/logo8e.jpg

The original 8th Schnellbootflottille had its harbour in IJmuiden, the seaport of Amsterdam. So we chose for that flottille. And no, there are swastika’s flying from our ships…
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5 January 2010 at 23:09 #6014
Roel
Participant
@roel
The Italeri kit made RC
6 January 2010 at 07:47 #24876
Bob Abell 2
Participant
@bobabell2
Hello Roel

Welcome to the Modelboats forum!

Your Schnellboot looks very impressive and fast and nicely constructed

What is the…..”Lurssen Effekt”……..I`ve never heard of this, please

Bob
6 January 2010 at 10:56 #24880
Roel
Participant
@roel
Hello Bob.

The “Lürssen-effect” was invented’by coindidence:

If the Schnellboot was travveling at speeds beynd the 28 knots, the small rudders were both set (by hand) on 30 dregrees outboard. This created a smaal hole of air behind the props, making them more effective. The speed increased by 1,5 knots, with the same RPM and fuelconsumption, thus making the S-boats faster. After obtaining the effect, the both outboard rudders were set at 28 dregrees outboard and stayed that way.

The effect stayed if the boat ran at more than 28 knots.

If the boat slowed down, the rudders were set “normally”, parallel to the centreline rudder.

This whole operation had to be done by hand, in the small, dark and messy space behind the machinerooms and galley, with the engines running at high RPM, and often in the midst of a firefight…

Not a job I would like to do!
6 January 2010 at 14:18 #24885
Francis Macnaughton
Participant
@francismacnaughton39461
Hi Roel,

Did you use the hull as supplied in the kit or did you do anything to lighten it? I would also be interested to know what your total weight of the finished model was and does the model at full speed plane over the water surface or is it still in displacement mode?

Thanks

Francis Macnaughton
6 January 2010 at 14:28 #24886
Francis Macnaughton
Participant
@francismacnaughton39461
Sorry Roel,

Having now watched the You tube I can see that the hull is definitely planing! It certainly heels a lot on the turns – does the Lurssen effect on the rudders increase the heel? Finally what total battery power are you using?

Francis
6 January 2010 at 16:51 #24888
Roel
Participant
@roel
Hello Francis.

She heels indeed…

Some friends of the 8th (model) Schnellbootflottille accusing me of my crews volunteering for the Eastern Front!

And yes, the Lürssen effect increases the heel a lot.

My batterypower:

Middlemotor: 9,6V NC battery 3200 mHh

Outboard motors 7,2 V NC Battery 2400 mHh

I can drive her for about 1 hour.
6 January 2010 at 17:07 #24889
Roel
Participant
@roel
Sorry, I forgot: the total weight (Including batteries) is 3,4 kg.

The hull is the hull supplied in the kit, made waterproof by 2 component cement in the keel.

In my 2nd Schnellboot I’ll have LiPo-batteries:

Outboardmotors 11,1V, inboardmotor 7,4V

Both accupacks delivering 3.400 mAh.

Benefit is the weight: 2 LiPo’s are less in weight than 1 ,6V NC-pack.

So the boat lies highter on the water and that means more speed.

So it’s important to keep the accupacks as low in the hull as possble.
7 January 2010 at 09:17 #24900
Francis Macnaughton
Participant
@francismacnaughton39461
Thanks for all that info Roel – it will help me get my version right although I doubt that I will be as adventurous on the rudders!

Francis Macnaughton
7 January 2010 at 19:48 #24904
Roel
Participant
@roel
If you have a computer transmitter, such as a FC16 or something like that, it’s just a matter of mixing things up! It’s worth a try!

It was some “trial & error”, but after a few hours button-bouncing even I succeeded.
10 January 2010 at 19:44 #24969
Roel
Participant
@roel
You can see here some members of the 8th (model) Schnellbootflottilje with their ships om a modelmeeting near Heemskerk:

[IMG]http://img193.imageshack.us/img193/5323/8e4.jpg[/IMG]

It’s very nice to see that the same model is treated in so many different manners:

one builder builts her for speed only, the other tries to put as much electronic gadgets in her as possible, another one goes for a historic correct ship…
11 January 2010 at 15:07 #24993
Francis Macnaughton
Participant
@francismacnaughton39461
Hi Roel,

Did any of the 8th flotilla try using the Italeri figure set to man up their S Boote and if so does the figure intended for the bow 20mm gun actually fit – it looks very cramped in there?

Francis Macnaughton
11 January 2010 at 21:59 #24998
Roel
Participant
@roel
Hi Francis

I do own the Italeri crew set for the S-Boot, but I didn’t take the crew out of the box yet.

I know the figure manning the front 20mm gun doesn’t sit in the proper way; he seems to sit on the deck.

I intent to play surgeon and somehow modify the figure so that he sits in the proper way iIN the gunpi… Not as a tourist on the deck…

If you look at this link

http://puffin.smugmug.com/Model-boats/S100-vaardag-21-09-2009/9944999_kokn9#678833290_JKq3S

you see 3 boats of the 8th.

The most right boat is from Maarten Flederus, a friend of mine, an his bowgunner sits indeed on the foredeck.

Enjoy the other pics…
12 January 2010 at 07:58 #25003
Francis Macnaughton
Participant
@francismacnaughton39461
Thanks Roel,

As you say – more like a tourist rather than someone intending to do something dangerous with the gun! Plastic Surgery must be the answer.

Francis
17 January 2010 at 23:39 #25113
Roel
Participant
@roel
These weeks, while the water was very “hard” in Holland, there was a slow progress in building the S-Boat.

I put two bulkheads in the model, one at te bow and one in the stern. So I will keep the central part, with the batteries and the electronics dry if there is any leakage in the bow or in the stern.

The S-131, my first S-Boat, suffered from some leakage in the bow section, around the torpedotubes and the gunmount, so I learned my lesson.

Also I cemented the reardeck now completely.Acces to the servos and the rudders is by two hatches: one over the depth-charge-rails. The other one is the higher part over the rear compartment. I sawed it from the reardeck, using a razor-saw, and put some styrene sheet vertical in it as a water-barrier.

Also I used a servo-slow to reduce the speed of the forward 20mm gun while traversing:

http://www.youtube.com/watch?v=2DSiMVYZjRY

Under the machineroom-cover I placed a ventilator to give the motors some fresh air. The air is drawn inside by the aft machineroom cover, wich I modified bij cutting the slots open. I also cut the front machineroomcovers open to let the air out.

http://www.youtube.com/watch?v=XAbGqNhVKWI&NR=1

Beneath the front machineroomcovers I placed a small speaker for the Dieselsound.

I think you cannot hear it when the boat is running, but that doesn’t matter; it’s just for fun, when the boat is on display.

http://www.youtube.com/watch?v=eZt3WF1pK2Q&feature=channel

Now it’s time for putting all the small, fiddly things on the model and give it the right coat of paint.

When I finished that, I think the water will be in its original form again, so she can have here maiden-trip…
26 January 2010 at 19:17 #25257
Roel
Participant
@roel
I started up my compressor this weekend and used the airbrush to give my 2nd Schnellboot some colors.

As with my first Schnellboot I will give her a number of a boat that is not documented.

So I can use my imagination for her camouflage or the armament.

I’m in doubt: shall I give her the 37mm “standard”gun on the reardeck, or a 40mm Bofors? Or perhaps a Vierling 20mm?

We will see…
14 August 2010 at 18:48 #28087
Iran Ausley
Participant
@iranausley59879
Roel,

Incredible work. Is there a diagram/kit for the linkage for the Lurssen effect or perhaps a website that has the geometry or the linkage diagram.

Thanks,

Iran Ausley
25 September 2010 at 01:50 #28446
Andy Hustler
Participant
@andyhustler32076
Dear Roel i have just started to buld the E boat and would like to know what colours you have used as i cannot find it on my Humbrol paint conversion chart . I would like to use tamiya paints ,but will bow to your better knowledge

                                            Many thanks



                                                  Andy
18 October 2010 at 19:35 #28634
Roel
Participant
@roel
Iran and Andy

Sorry I reply so lately… I’ve been in Bosnia for a few months, working for EUFOR as a Warrant-Officer in LOThouse Travnik.

@ Iran: I did it this way:

The middle rudder is activated by a standard servo, both the Lürssenrudders have their own miniservo.

[img]http://img139.imageshack.us/img139/4797/aansturingroerencg1.jpg[/img]

On my transmitter:

Central rudder on channel 4, Lürssenrudders on channels 1 and 2.

I mixed channel 1 and 2 with a V-tail-mixer. Easy!

@Andy:

The “Schnellbootweiss” is nowhere for sale.

It is the better “judging”: I use Tamiya Acryl also, so I mixed a complete flask Matt white with 3 tiny blobs of matt black.

And remember: it was war-time! Boats were used very intensively, there was ample time for maintenance of painting…

Some people build their boats as if they came that day of the slipway… I don’t.
21 October 2010 at 18:15 #28658
RedPanda
Participant
@redpanda
Hi Roel,

Excellent model, thanks for sharing.

I’ve flown model aircraft for many years but I’m new to model boats so please forgive a dumb question!

I’m a bit confused about how you have set up your radio. You say that you have the Lürssen rudders on a V-tail mixer. In an aircraft, that would be the rudder and elevator but for this application, I think it would be rudder and an ‘elevator’ channel controlled by a three position switch so you could preset the necessary 30 and 20-ish degree outward deflections?

Also, do you have the main direction control, ailerons in an aircraft but your channel 4, mixed to the Lürssen channels so all three rudders turn together when the main rudder is used?

Thanks for your assistance,

Richard
24 October 2010 at 22:39 #28671
Roel
Participant
@roel
Hi Richard..

I can program my transmitter with the V-tail-mixer on channel 1 and 2 (Right hand stick)

With “servo end point” on the transmitter I can stop the servo’s at the desired position.

So I programmed them to give the Lürssen rudders 30 degrees max.

And with the “master” on channel 4 and the “slave” on channel 2 the Lürssen rudders move together with the central rudder. This makes the boat extraordinary agile.

I can even turn on the spot at slow speed, by giving the central motor dead ahead and the rudders max to port of starboard. With the outboard motors slowly backwards the boat stays on the spot or moves very slowly forward, but turns in place.
27 October 2010 at 13:34 #28696
RedPanda
Participant
@redpanda
Dank u wel Roel, very useful information!

I thought about your advice but with my aircraft radio, a JR DSX9, my right hand stick is spring loaded to the centre on Ch2 (elevator) and I really wanted to have the Lürssen rudders on a 3-position switch.

I decided to use a program mixer and set the Flap channel (Ch6) as the master, as it is a switched function already, and the Gear channel (Ch5) as the slave. This gave too much movement at first so I changed the sub trim and end point settings as you suggested and all now works well.

I then used two further program mixes to make the Aileron function, Ch1, a master to both Ch5 and Ch6 so that all three rudders turn together.

I am almost there now but I hope you will bear with me for two more questions!

You say that you can turn the boat on the spot, partly by having the central motor ahead and the outer motors astern. I was wondering how you did that as the FC16 seems to have a single throttle stick?

Also, I saw earlier in this thread that you have the Lürssen rudders first at 30 degrees and then at 28 degrees. From the research I have done on the Net, there seems to be complete agreement on the 30 degree value but, once the effect has been achieved, above 25 knots, there seems to be a range of values quoted for the lower angle, right down to 17 degrees. Is the lower value critical do you know or is “a bit less than 30” ok?

Thanks again,

Richard
27 October 2010 at 16:31 #28697
Roel
Participant
@roel
Hello Richard.

The “gas throttle” for the middel motor is a sliding switch in the middle of the FC-16 or

(on my new 2,4 gHz transmitter) a rotary switch on the right hand upper side of the transmitter.

That’s the way I command my engineroom.

About the Lürssen effect:

As the boat is on scale and the water is not, we modelbuilders cannot achieve the true Lürssen effect. I canot see any increase of speed. On the original boats however this was only 1,5 knots, so the difference on 1:35 will be so small we can’t see it.

I sweep my Lürssen rudders on a angle of 25 or so degrees and keep them there at full speed. What i can see is:

The boat will level on the watersurface; the bow goes deeper in the water.

When taking sharp corners the difference is very clearly.

Without Lürssen effect the boat steeply heels to the inner circle. The outer prop sometimes comes above the water.

[IMG]http://img26.imageshack.us/img26/3356/58484531.jpg[/IMG]

With Lürssen effect the boat keeps staight on the water. No heeling whatsoever. The corner is just as small as without Lürssen effect, but the boat looses some speed.

http://img263.imageshack.us/i/16967536.jpg/
27 October 2010 at 16:49 #28698
RedPanda
Participant
@redpanda
Thanks very much Roel, that was exactly what I needed to know. Your assistance is appreciated.

So…when do we get to see your next Schnellboot? Is next week too early?

Richard
27 October 2010 at 20:06 #28701
Roel
Participant
@roel
I think so… I just finished the “engineroom”:

Speed 500 in the middle, brushless BMI Spitz 85562 as outboardmotors.
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