M.A.S. 562 Torpedo Boat – Just finished with cool video !

[Ruben VasconcelosParticipant @rubenvasconcelos52946]

[Ruben VasconcelosParticipant @rubenvasconcelos52946]

Hi,



I'm an rc plane guy but after a few builds, decided to build my first rc boat. It was that or an hydroplane…



Having a crush for torpedo boat's, after a google search, found an excelent free plan of a MAS italian boat. I've printed it for a 1:24 scale. The boat has a 84 cm length.

The plan can be found here:

**LINK**



It was built during past 4 months and I've used just scrap wood from past plane builds.

Also used objects that normaly would be trash, like bottle caps, pins, plastic cases, credit cards (expired), etc.



Power is from a speed 480 brushed motor coupled with a 4:1 gearbox, plus a 30 amps ESC and a 2200 3s lipo.

With a plastic 3 blade 40mm propeller, I think it achieves a very scale speed.

With this setup, can play for 10 to 15 minutes.

The ESC hasn't reverse so I built a system using a servo and a switch to reverse rotation in motor.



First time in water was two weeks ago and it was a success !

I've made a cool video that can be found here (with sound please !):

**LINK**

[Ruben VasconcelosParticipant @rubenvasconcelos52946]

Some pictures:

[Bob Abell 2Participant @bobabell2]

Hello Ruben

Congratulations!……..Excellent model build……..Very neat and tidy

Excellent photography……..I like the black background!

Very creative video…..With interesting story line!

Keep up the good work

Bob

[Ruben VasconcelosParticipant @rubenvasconcelos52946]

Hello Bob !

Thank you very much !

This build was great fun and a lot diferent from building planes…

Best regards,

Ruben

[shipwrightParticipant @shipwright]

Ruben,

Very skilful and impressive build considering you are only using scrap material. What is the displacement weight of the model (including batteries etc) ? With regard to full scale speed your video says that the actual torpedo boat was capable of 42 knots. Scaling for speed you take the square root of the scale factor (ie square root of 24 for your model) to arrive at the appropriate scale max speed for your model. Do you estimate that your model travels at 42/5 = 8.4 knots when going full speed – that is quite fast and I would have expected the boat to be "up on the plane" (ie bow out of the water). I have a scale (1:24) MTB (HMS Biter) which is similar size to your boat and it has 2 x Graupner Speed Eco 600 dc brushed motors consuming about 9 amps each at 7.2 volts when at maximum speed and the bow is planning. Another point is where is the balance point – midship or aft of midship ?

Regards

Ian

[BanjomanParticipant @banjoman]

First of all, please let me join in the well-deserved praise of a very nice-looking and impressively built model!

When it comes to scale speed for the specific scale, of 1:24, a useful rule of thumb for veryfying that one's model travels at the right is to divide the full scale speed in knots by 10 — the resulting figure will be sufficiently close to the corresponding scale speed in metres per second!

To take the case of an MTB doing 42 knots full scale, the sqaure root of 24 = 4.898979485566356, which when used to divide 42 gives a scale speed in knots of 8.573214099741124 which in its turn is equal to 4.41044236 or, rounded off, 4.4 m/s — which I think is close enough for practical purposes to the rough approximation you would get from diviing 42 by 10, namely 4.2.

The advantages of this rough-and-ready method of calculating the scale speed at 1:24 in m/s are twofold: it is a very simple calculation that most anyone could do in his or her head, while a metres-per-second speed is much easier to verify at the pondside.

Alas! The division-by-ten rule only happens to work at 1:24, but in my view it is nevertheless quite useful to convert the scale speed from knots to metres per second when checking how fast the model is travelling over the water, as this lets one work with distances and lapses of time more easilly established and measured at the pond than nautical miles and hours …

/Mattias

[Author]

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