Nautical Marine Models Vosper Perkasa

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Nautical Marine Models Vosper Perkasa

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2 October 2009 at 21:56 #23361
Aridlands
Participant
@aridlands
Hi,

I like the look of the Nautical Marine Models Vosper Perkasa P150 but the pictures from the recent review in Model Boats suggest that the model is significantly overweight. This shows itself because as it sinks so low at the back as the speed builds up (a typical characteristic of overweight longer planing hulls). The slow shots also indicate that the freeboard is low.

Has anyone else built this model and achieved a lower running weight?

Where is all that weight coming from, is it the resin castings?

Thanks,

Al
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2 October 2009 at 21:56 #6003
Aridlands
Participant
@aridlands
Vosper Perkasa P150 kit
17 September 2011 at 14:34 #31812
Howard
Participant
@howard79726
Hi Al,

Just trawling the site and noticed your posting from near enough 2 years ago!

I’m now close to completing this model and, like you, have become suspicious of the weight of some of those castings, to the extent that I have cut a fair amount of (unseen) resin from some of them, one or two others I have rebuilt in styrene for lightness.

Performance on the water will deliver the final verdict however, and that’s still 3 or 4 weeks away.

So, having seen your post, I wondered if in fact you did go ahead with this model and, if so,

how did the build go? I’ve encountered a few brain teasers along the way and gone my own way with some of the more cosmetic elements.

Regards,

Howard
17 September 2011 at 16:15 #31817
Aridlands
Participant
@aridlands
Hello Howard,>>

No I did not buy and build the model in the end. I do
however have a built Precedent Perkasa and that turned out to be very light and
takes very little power to get it to plane nicely.

Good luck with you model. Keeping the model light is a
good idea.

Regards,>>

Al>>
17 September 2011 at 16:29 #31818
Aridlands
Participant
@aridlands
Hello again Howard,

My 37″ Perkasa model has a running weight of around 3kg.

Hope this helps.

Al
18 September 2011 at 16:05 #31830
Howard
Participant
@howard79726
Al,

Thanks very much for the responses; from the photo your model seems to run very nicely (I’m curious about what appears to be clinging to the starboard rear torpedo) and I’m sure

your choice of kit was a good one.

However, keep an eye on this thread and I’ll post a pic of my completed model, hopefully running nicely, in a few weeks.

Also, your indication of a running weight gives me a useful guide – thank you!
19 September 2011 at 00:22 #31838
Aridlands
Participant
@aridlands
Hi Howard,

Well spotted! The thing tied to the torpedo is an LCD “PowerPanel” display for the onboard Eagle Tree data logger. This was installed for test purposes as I could see the speed as measured by the onboard GPS, the prop RPM as well as the main battery voltage and current. In my high resolution copy of the photo I can see the following:

Battery voltage: 7.92 Volts

Battery current: 8.4 Amps

Propeller revs: 4437 RPM

Speed: 8.4 mph

So since watts = Amps x Volts the motor power is 66 Watts. So this is 22 watts per kg of weight. This is about the minimum it needs to plane.

The motor is a robbe unit with a gearbox.

The model has a single prop shaft (this help keep the weight down and is “simpler” to install and wire up). The prop is an old 4 blade brass one with a diameter of about 42mm.

I’ve now got the Jeti Duplex system so now have a display attached to the transmitter that tells me these things.

The model now has a brushless motor fitted and is much faster (about 11 mph) at the same motor power.

Cheers,

Al
12 November 2011 at 17:49 #32415
Paul Swainson
Participant
@paulswainson22480
I have built this model back in 1998/99 all the the materials was wood and a fiber glass hull. I used a single drive motor and then a 12 v gel bty. All the fitting was wood. I would like to upgrade the fitting as some off the torpedo stands are poor build, could some one advise me where I can get some castings to change with the wood ones I made.
13 November 2011 at 10:56 #32418
Howard
Participant
@howard79726
The Nautical Marine model included all the castings (resin and white metal) for the torpedo racks etc. and, with the usual care and preparation these produce a good result that can be added to and embellished as required. They sell items such as Bofors and Oerlikon gun assemblies separately so they may well sell these items separately. They’re nice people to talk to – certainly worth a call I’d say on 01704 894 006.

Work and family matters have slowed my progress on this project but it’s at the detail and painting stage now so, weather permitting, we could have a launching in the next few weeks ( or Springtime if it’s the promised harsh Winter down here!).
13 November 2011 at 16:03 #32420
Paul Swainson
Participant
@paulswainson22480
Thanks for the info will give them a call and see if they can help me inprove my old model.
11 October 2012 at 18:07 #36978
Howard
Participant
@howard79726
Very belatedly I thought I should round of my contributions to this thread by mentioning that I finished the NMM Perkasa early Spring 2012, and have been sailing her a fair bit, plus trying out different batteries, engines and propellors. The performance is now OK-ish but there's a lot of weight in some of the resin details and I've made some lighter torpedos to help.

I'm now well into building a 1/32 Higgins PT boat from Peter Miller's plan in Model Boats – I'm hoping this will be quite spritely. Also, I have a Thunder Tiger Voyager 2 yacht lurking, as yet unassembled, in the spare bedroom!
17 November 2012 at 11:20 #37635
captainslog
Participant
@captainslog
Hi Paul, re your torpedo racks. For my 48" I scratch built mine. I managed to get some quality fotos of the full size ones and scaled them down. It also helps when your uncle worked on a full size perkasa many moons ago.Iff you are interested I can post some fotos of them and I think (not certain) that I filed my drawings somewhere. They take a long time to makemind, due to the large no. of parts involved let me know ok keith
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