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Author Topic: vosper ferocity !  (Read 10009 times)

triumphjon

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vosper ferocity !
« on: June 29, 2010, 08:29:42 pm »

a freind has just bought an unfinished model on fleabay , currently running a single shaft but not after this weekend as its being put right ! the shafts arent a problem as we are going for a pair of m4 12" ones (perkins ) fitted with oilers . has anybody got any photos of the correct profile of the rudder blades please ? the standard available off the shelf ones arent very scale like ! ive tried to find links via google , unfortunaatly  vospers arent very helpfull & im still waiting for the historic dockyard ( portsmouth ) the military power boat trust is now amalgimated within this .  as a scale boat it would be good to be correct below the waterline as well as above it ! jon
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triumphjon

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Re: vosper ferocity !
« Reply #1 on: July 11, 2010, 09:50:21 pm »

too late , ive copied the profile of a pair of brave class rudders ! the motors have now been delivered , ordered a pair of 700 size & got a pair marked as 975 s ? same can length  as a 700 & about 3mm bigger in  diameter , amps draw on the bench using a 7.2 volt nicad is around 8 amps each ! off to the lake this week to run the pair together for further test ( dont fancy flooding the flat downstairs as they empty our bath tub ! ! ) this boat is the vosper that never got ussed by our own navy for more than 3 weeks !
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Perkasaman2

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Re: vosper ferocity !
« Reply #2 on: July 12, 2010, 01:13:29 am »

Hi jon, A 2 sheet plan is available seperately from Fleetscale (Calalogue No.  VOS95)  titled  'VOSPER':

www.fleetscale.co.uk/system/index.html

The Ferocity type was developed by Vosper from the 'Brave' Class to provide a less expensive, but similar performance alternative. Your Veron is based on an entirely different Vosper vessil, although the bridges of both craft appear  to be very similar.......... hence the confusion. There are substantial differences in hull design and the true Ferocity was much faster ( twin gas turbines - 50knots )than the Trinidad & Tobago 'Patrol' design on which the Veron is based ( diesel powered 30 knots ,or less?)
I have owned and converted the Veron and twin 700BB will give a good performance, although the large 52" hull is by no means lightweight or shaped for speed although it will 'plane' to some degree on powerful motors and high output batteries. (I used twin large 12v 7amp s l atype). The original model was not highly detailed and I had to cut'n trim frames ets to fit twin shafts/motors and also lighten the hull.  :-)
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triumphjon

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Re: vosper ferocity !
« Reply #3 on: July 12, 2010, 06:19:14 pm »

thanks ,  id realised there are many differences twix the two vessels , i had been useing the information id been given , ive now fitted the shafts / rudders useing the dimensions listed for the more common perkasa models , ie 13" shafts ' 5" centres with the rudders fitted about 1" from the transome , the only internal cutting was to drill a pair of holes for the shafts to pass through a bulkhead , the motors are fairly close to the hull floor thus keeping the shaft angle as shallow as i can . as you say its a heavey model so will be lightening it wherever possible which is a little trickey as its already biult in the hull & basic superstructure . we are looking to run on nimh high capacity battery packs at either 9.6 or 12 volts , using a pair of pack to also increase the amp rates ! jon
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Perkasaman2

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Re: vosper ferocity !
« Reply #4 on: July 13, 2010, 02:25:39 am »

Hi Jon, Looks like you've cracked it!  ;) The stern of the veron is wider than the slightly shorter Perkasa so there's plenty of room. In my experience scale size rudders mean  scale sized turning circles. but deeper/larger  patten rudders can be more effective in deflecting propwash to assist turning. I was sorely tempted to strip back the forward hull and  re-shape the bow/first frame but later decided that preserving the original 'veron look' was more important.  :}
 

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triumphjon

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Re: vosper ferocity !
« Reply #5 on: July 13, 2010, 11:18:41 pm »

the way ive set it up now most of the weight is from midships to stern ! working the theory that the bows may unstixk from the surface tension of the pond quicker , time will tell ? motive power being 9.6 nimh sub c cells which happen to fit nicely between the keel & the relocated propshafts ( the keel stops them moveing one way while the propshaft keeps them from going the other way. jon
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triumphjon

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Re: vosper fast patrol boat
« Reply #6 on: August 30, 2010, 09:27:50 pm »

the biuld is progressiing slowly , we have now got a set of veron plans , and found some useful photos of some of the malaysian vessels that give better details of deck fittings . we have decided to make the guns both front and rear able to train up/ down and rotate although not able to fire ! , unfortunatly the first motor choice wasnt as good as we origanally thought as when installed they were drawing almost 16 amps each and thats while on the test bench ? its now awaiting some new lower drain motors , should any body have any sugestions that dont cost the earth please let me know  ? ? sorry for those who would like to see pics ive been unable to upload any !
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triumphjon

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Re: vosper ferocity !
« Reply #7 on: September 14, 2010, 10:32:25 pm »

new motors were supplied last saturday , a pair of park 450 brushless ones , the mountings are bolted to some slightly modified brushed type 400 mounts ! the esc provided me with a slight headache to set up as i was unable to get the setting for boat use (sorted now after a call to logic ) ive also disabled the bec side as im running a spearate receiver pack . the wirering has taken the best part of two days to biuld a loom , install everything for the working systems , all useing different coloured cables ( except the negative which has a common colour ) and securing the loom inside the hull neatly !  i hate looking at a rats nest of wires ! ! and while ive made the loom ive also recorded the colour codes for the whole job for future referance . the boat is starting to look like a working ship , as the foward gun now works in two directions ie ; rotation of the gun and barrel elevation . the radar is also motorised , along with working search & navigation lights , most of the fittings have been fabricated from brass . i will attempt to add some photos soon , when my partner can load them for me .
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triumphjon

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Re: vosper ferocity !
« Reply #8 on: September 20, 2010, 07:40:23 pm »

to all that have been watching , the boat had its first and second "sea trials " this weekend , the first trial on saturday lunch time was running on my pair of 7.2 volt nimh packs  (one per motor ) performance wasnt as quick as we would have liked ! after a trip into the local model shop with the boat , a 12 volt 7 ah gel battery and charger were purchased , more modifications to the compartment between the rudder and motor sections were needed to secure the new bigger battery , this was done useing more 3mm ply , and some 25mm pine square for support / spreaders along the hull floor . afteer some trying times on sunday morning when the 2.4 ghz radio wouldnt respond to anything ? with everything now operating it was off to the lake for more testing . results were much more pleaseing to watch , the model now gets onto the plane , and had a run time of almost an hour !
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Perkasaman2

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Re: vosper ferocity !
« Reply #9 on: September 21, 2010, 08:21:04 pm »

Excellent  :}
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triumphjon

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Re: vosper ferocity !
« Reply #10 on: September 21, 2010, 08:47:12 pm »

thank you , im still waiting for wokingkev to post the photos ! 
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wokingkev

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Re: vosper ferocity !
« Reply #11 on: September 22, 2010, 05:59:38 pm »

Hi Jon and All
Many thanks to Jon for all his hard work ,.my hands are not up to much owing to arthritis. As Jon Said with luck I have uploaded some pictures, the build has continued for this I will take my camera and get some latest shots.





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Shipmate60

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Re: vosper ferocity !
« Reply #12 on: September 22, 2010, 08:21:10 pm »

She looks tidy now and slightly unusual from the usual Perkassas.
I might have to pop down and see her run!!!

Bob
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DickyD

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Re: vosper ferocity !
« Reply #13 on: September 22, 2010, 08:33:35 pm »

Wish you lot would post your pictures the right way up, it dont do the old neck any good at all.

Nice job by the way. :-))
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triumphjon

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Re: vosper ferocity !
« Reply #14 on: September 22, 2010, 09:32:09 pm »

sorry dicky , it wouldnt fit in the lens of my camera any other way !
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RaaArtyGunner

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Re: vosper ferocity !
« Reply #15 on: September 22, 2010, 10:37:50 pm »

sorry dicky , it wouldnt fit in the lens of my camera any other way !

It's OK they look perfectly fine from down here  O0 O0 %) %)
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wokingkev

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Re: vosper ferocity !
« Reply #16 on: September 25, 2010, 07:07:40 pm »

Hi All
I have posted the boat on her second trip out, it was taken on a i phone so it is not of the best quality, but shows her running.


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cdsc123

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Re: vosper ferocity !
« Reply #17 on: September 30, 2010, 07:25:22 pm »

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triumphjon

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Re: vosper ferocity !
« Reply #18 on: September 30, 2010, 10:49:34 pm »

thanks for the link , weve got an original veron plan , although have chosen the malaysian navy to base the build on as there are more reference pics available , the forward gun has been scratch built with a micro servo hidden inside the body that enables the barrel to elevate , rotation is now via a metal geared servo mounted below deck & transmission through an alloy tube to the base of the gun unit , currently the rear gun is static , but that may change in time ! most of the fittings have been scratch built using brass , or wood . its still however an unfinished project although it is undergoing " sea trials "  as its the first vessel that ive fitted brushless motors into , its currently running a pair of park 450 outrunners through huco couplings onto some m4 shafts & turning 40mm dia 3 bladed graupner plastic propellers , last weekend it run for about one and a half hours  continually around the lake , both the motors , escs & battery were still cold !  although a little cavitation is seen behind the vessel at anything above 1/4 throttle ?
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cdsc123

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Re: vosper ferocity !
« Reply #19 on: September 30, 2010, 10:57:06 pm »

Intriguing, perhaps the shaft angle is too steep for so much power?
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triumphjon

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Re: vosper ferocity !
« Reply #20 on: October 01, 2010, 09:33:10 pm »

the shaft angle is as shallow as it can be , its not far from horizontal ! next time wokingkev & i go to the lake together we should be able to get some better photos of the vessel underway , its a possibility that the props dont have enough pitch or maybe too small in diameter ?
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Perkasaman2

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Re: vosper ferocity !
« Reply #21 on: October 12, 2010, 12:32:50 pm »

Hi triumphjon, it might be worth testing/comparing performance with your batteries wired in  both parallel series. Your low kv BL higher torque motors may just need more voltage if the prop sizing  is adaquate.What is the spec of the brushless esc?
Experimenting with various prop sizes using inexpensive 2 blade plastic props (supplied in S and  the X steeper pitch versions) may help tol  indicate over/under 'propping'.
Undersized props willl certainly cavitate (egg whisk) and fail to exert sufficient thrust to ensure the hull is moving forward quickly enough to enable an adequate flow of 'solid' water to the props. Weight placement in the hull needs care to avoid excessive 'stern deep' trim which results in the hull 'snow ploughing', a condition which slows the hull and wastes precious thrust and battery power.   
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triumphjon

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Re: vosper ferocity !
« Reply #22 on: October 12, 2010, 10:23:07 pm »

the current set up is as follows ;- a pair of e flite park 450 motors rated at 890kv , direct driving to m4 shafts turning 40mm 3 bladed plastic props , speed control is a pair of fusion tornado bl 30a hv escs , currently we are runing on a single 12 volt 7 ah gell battery , ive fitted the boat so that the rudder servo and steering gear are in the rear compartment , the next compartment has the main 12 volt battery , and the 2.4ghz receiver , it also has a bank of master switches ( radio , main radar motor , nav lights , search lights ) , both the rx and the switches are just below deck level , in the third compartment ive got both motors , and the receiver battery , the foward two compartments are empty , the model is giving a reasonable battery duration and the speed doent seem to bad considering the size of the boat , at full throttle on a fully charged battery the bow lifts out of the water as far as where the bow fairs into the keel ! the model was tested with a cross wind and a three to four inch high chop ! . i ws going to try different props in an effort to see if it would improve the performance ?, do they sell two bladed props in oposing hands , as this model has contra rotating shafts , which currently rotate away from the keel ( port , anti clock  starboard clock wise when veiwed from the stern !
 jon
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Perkasaman2

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Re: vosper ferocity !
« Reply #23 on: October 13, 2010, 01:42:22 pm »

Hi jon, your extra info/feedback is  helpful and very encouraging. The hull is planing nicely on your current spec and this is achieved on moderate voltage (12v) from a single s.l.a. and your BL motors are running without cooling. Well done!
 
I suspect the props are'nt cavitating. It would be interesting  to fit/trial a pair of  black 45X plastic props and compare performance, if clearance allows. These very coarse pitch props may suit the motors and give a thrust/efficiency advantage. I don't think these inexpensive props are available 'handed' and some small side or lateral thrust is unavoidable, which would be cancelled out with twin outwards or inwards running props.   
 
Performance Nimh battery packs are expensive, however, doubling any of the 7.2v, 8.4v, 9.6 or 12v packs available will enable a range of higher voltage choices for trial, although motor cooling coils may be required. Doubled packs must be identical in ALL respects including 'state of charge' to minimise mismatch issues. A pair of borrowed 'matched' 7.2 buggy packs could allow a trial  of 14.4v running.
 

 




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triumphjon

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Re: vosper ferocity !
« Reply #24 on: October 17, 2010, 10:52:29 pm »

due to my local shop not having any other props at present more tests havnt been done , unfortunatly now the 12 volt gell battery is fitted it doesnt make swaps easy without removing a large section of the deck ! 
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