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Author Topic: MFA Piranha Mk II  (Read 5694 times)

Nige52

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MFA Piranha Mk II
« on: April 01, 2011, 11:59:01 am »
We are discussing starting a new class of club racing boat, faster than the Club 500's, maybe even using brushless motors, nothing decided yet. But we are looking for a boat that is economical, tough and widely available, so have come up with the MFA Piranha Mk.II
Does anyone know if these boats are self righting in case of er...accidents?
Thanks
Nige
 :-))
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BigA

  • Guest
Re: MFA Piranha Mk II
« Reply #1 on: April 01, 2011, 12:13:34 pm »
Never had to test the self-righting but the design doesn't look to be capable - quite a broad, flat hull moving towards the stern, with chines like small 'pontoons' - unlike the hull design of the 500. The Piranha, however, is VERY stable especially in tight turns. I found it to be quite heavy (thick/large fibreglass hull) and, consequently, comparatively slow (I ran a couple of Graupner 500-600 size motors with 9.6V pack) - it quickly drained a 3800mAh pack (less than 10min).

Some shots of my boat (now sold) here: http://www.modelboats.co.uk/albums/member_album.asp?a=8861

 :-)
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Nige52

  • Guest
Re: MFA Piranha Mk II
« Reply #2 on: April 01, 2011, 12:30:03 pm »
Very nice boat there  :-))

Hmmm, heavy eh? What we're looking for is something a bit more modern looking (And faster) than the aged Club 500....but the ability to self right after a collision would be a bonus. There are plenty of fast electrics out there which would do the job but....moneywise are too much for novices and fun boaters.
Thanks
Nige
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BigA

  • Guest
Re: MFA Piranha Mk II
« Reply #3 on: April 01, 2011, 01:00:44 pm »
The jet-boat conversion (your website) might lend itself to a good race series!
( http://www.nuttynige.com/Jet%20boat%20rebuild.htm )

Interesting that you do vinyl decals - I may be in touch!
 :-)
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Nige52

  • Guest
Re: MFA Piranha Mk II
« Reply #4 on: April 01, 2011, 01:41:24 pm »
I should have added on the site that the Tear Into is no longer running..... {:-{ We had previously considered it but the cost in converting them plus the cheapo water jets that are installed don't make the boat very robust....they go very well to begin with, but the quality soon shows it's true colours, plus of course, they are not self righting..
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balders

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Re: MFA Piranha Mk II
« Reply #5 on: April 01, 2011, 11:01:18 pm »
Hi,
   We run a 500 series of racing at our club and we too found we wanted to step it up a notch.After several trials we settled on MFA Pirahna.We started with the recommended set up and then over a12 month period we finally settled on a brushless set up driving a graupner 31mm S Prop on 8.4v  nimh.They run really well and fast but are not built to be self righting.We have tweaked ours by removing the kit bulkheads and put polystyrene in where we can and make sure the tops taped down and so far they mostly self right.Another mod to improve handling is to alter the shape of the rudder.

All these little wrinkles came from our fast electric secretary who has raced at national level so knows a thing or two and was keen to build on the interest generated by the 500 class,We now run both classes.If you would like more specific info about these let me know and I will take some pictures and find out exactly what motor and s/c we use and show the rudder with dimensions.(motor and s/c came from giant cod)

                                                                                                                                    Regards Andy
                                                                                                                                    (Balders)

                                                                                                                                                                                                                                         
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Martin (Admin)

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Re: MFA Piranha Mk II
« Reply #6 on: April 02, 2011, 03:41:20 am »
Have you got any picture of the modified MFA Pirahna's Andy?



     http://www.modelboatmayhem.co.uk/My_models/01%20piranha.htm
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Nige52

  • Guest
Re: MFA Piranha Mk II
« Reply #7 on: May 23, 2011, 10:57:06 am »
Yes, have you taken any photo's yet Andy?

 :-)
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balders

  • Guest
MODIFIED PIRANHA PICTURES
« Reply #8 on: May 24, 2011, 11:05:55 am »
Hi,
   Sorry for the long delay :embarrassed:Wanting to step up from club 500 racing we chose the MFA PIRANHA after testing several other boats.

   12 months tinkering at the waterside and we chose the following as the best for our location :- Brushless motor which came from GIANTCOD but am unable to tell yuo exactly which it is!
                                                                                                                                        HOBBYWING Pentium 40 opto brushless speed controller turning a Graupner 31mm 2 blade prop on 8.4 NIMH battery.

  This set up gives great speed and is ideal for the 4 minute heats we run.

  As you can see the original deck and cockpit has changed.The factory version with the pull off cockpit is too flimsy for repeated lifting on and off at the waterside on race days.Ichose to fit a new deck with a large opening and the original supplied deck and cockpit are fitted together with additional bracing insde the cockpit so it will stand pulling about.I also chose to epoxy some nuts on the underside of the fixed deck and bolt the top on prior to the race.It works and no water gets in but is fiddly in winter when it's cold and tiddling down at the waterside.

This led to a further development on a friends Piranha where a false deck was fitted and the supplied deck with cockpit mounted was slid into a channel from the stern.This proved to be much simpler and less f.f..f..fiddling about when its cold!I will get some pics of it later and post.

Hope this helps and apologies for the big delay.Hopefully you should have a few pics to peruse below.

                                                                                                                                              Regards Andy :-)) :-))











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Nige52

  • Guest
Re: MFA Piranha Mk II
« Reply #9 on: May 24, 2011, 01:41:14 pm »
WOW!!
Exactly what I'm looking for Andy, thanks very much and I'm looking forward to any more pics you may upload  :-)) :-))

Cheers
Nige
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Patrick Henry

  • Guest
Re: MFA Piranha Mk II
« Reply #10 on: May 24, 2011, 01:53:44 pm »
Food for thought, eh Nige?
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Nige52

  • Guest
Re: MFA Piranha Mk II
« Reply #11 on: May 25, 2011, 09:49:32 am »
Yes it sure is Rich.....
We are now in discussion as to what power plant to use, brushed/brushless/NiMh/Lipo etc...or even water jet. I think that it has been decided to adopt this boat as the one we'll be using, but we have to make sure that our members are in agreement as to what the internals will be. Have you built yours yet?
 :-)
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Patrick Henry

  • Guest
Re: MFA Piranha Mk II
« Reply #12 on: May 25, 2011, 09:54:57 am »
Made a start on it Nige...motor mount/rudder/ installed, made a start on the radio installation, and in between that I'm trying to decide whether to fit the top moulding or just cut the access hole a bit smaller and fit a tape down flat top.

Decisions, decisions...


Rich
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balders

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Re: MFA Piranha Mk II
« Reply #13 on: June 12, 2011, 03:39:41 pm »
Hi Nige ,
           Pictures of the slide version of Piranha.This is the prototype and can no doubt be improved upon.If the photo's don't explain then I will be happy to try and help further.I forgot to mention in the original post that we also made alterations to the supplied prop.This was a tip shared by our race sec. who used to race nationally. I have made and photgraphed two diagrams which will help more than several paragraphs of text.If you do this and tweak the rudder throw it is possible to run it flat out around the bouys.
                                                                                                                           If you need any help you are welcome to pm me.

                                                                                                                           Cheers Andy
                                                                                                                           Derby M.B.C
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Nige52

  • Guest
Re: MFA Piranha Mk II
« Reply #14 on: June 13, 2011, 08:10:20 am »
That's absolutely great Andy! Thank you very much for your time and trouble to take those pictures, it'll help us in the club enormously in deciding which way to go ahead with the builds  :-)
Thanks again  :-))
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