Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1] 2 3   Go Down

Author Topic: Prop for deep v??  (Read 12811 times)

Lt. Raen

  • Guest
Prop for deep v??
« on: April 22, 2010, 03:38:36 AM »

G'day I'm from Sydney Australia an am currently looking for a prop for the 1.2m deep v I'm building out of ply.

I am looking for advice on what size prop to match to the 25cc blower/vac motor i going to run in it.

also any advice on good suppliers for a prop would be welcome

Cheers, Raen
Logged

HS93 (RIP)

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,949
  • I cannot spell , tough
  • Location: Rainhill UK
Re: Prop for deep v??
« Reply #1 on: April 22, 2010, 04:27:11 AM »

you may find what you need
hear



http://www.prestwich.ndirect.co.uk/

Peter
Logged

w3bby

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 773
  • Location: Helsingborg, Sweden
Re: Prop for deep v??
« Reply #2 on: April 22, 2010, 08:34:37 AM »

Octura 470, 475 or 480 should be a good start I would have thought.

Check out the AMPBA site for your local suppliers http://www.ampba.asn.au/links.htm and don't forget your local club for help and advice http://www.modelboatclubofnsw.com/

Lt. Raen

  • Guest
Re: Prop for deep v??
« Reply #3 on: April 22, 2010, 10:18:20 AM »

Thanks for all the help guys i think i have everything i need to get this baby on the water now %%
cheers, raen
Logged

BJ

  • Guest
Re: Prop for deep v??
« Reply #4 on: April 30, 2010, 08:31:16 PM »


I am looking for advice on what size prop to match to the 25cc blower/vac motor i going to run in it.

also any advice on good suppliers for a prop would be welcome

Cheers, Raen

IAs a guide, it might be old (1992) but the charts are still valid. Prop Shop have however changed the description of some of their props.
See the attached Charts
Logged

Lt. Raen

  • Guest
Re: Prop for deep v??
« Reply #5 on: May 04, 2010, 07:09:00 AM »

After a lot of thought on this i have decided to go with surface drive over submerged drive
I was originally going to go with a submerged drive however engine mounting really only will allow for a surface drive set up.

Anyay i want to pick your brains on what hardware set up i should go with
i was thinking the SF2 or SF3 from this site: http://www.prestwich.ndirect.co.uk/surfacedrive.htm

but i just wanna make sure on my choice before sinking anymore money into this project
 :-))
Cheers
Logged

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,502
  • Location: Blackpool
Re: Prop for deep v??
« Reply #6 on: May 04, 2010, 07:47:54 AM »

You would be best getting your gear from Aus wouldnt you? theres a few good dealers over there that stock all you need.Heres one my mate in Perth uses a lot.Good prop for a weedy engine is the prather 280 or octura 480,another is the p275,basicly you need a big prop because weedys dont rev high enough to spin the smaller props fast enough so you take advantage of the torque by using a big prop.Stick a walbro wa 167 carb on it and it will improve quite a bit also,thats about the best carb for these motors but anything with similar size intake would work better than the stock carbs.
http://www.hobbydepot.com.au/
Logged

HS93 (RIP)

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,949
  • I cannot spell , tough
  • Location: Rainhill UK
Re: Prop for deep v??
« Reply #7 on: May 04, 2010, 12:40:24 PM »

You would be best getting your gear from Aus wouldnt you? theres a few good dealers over there that stock all you need.Heres one my mate in Perth uses a lot.Good prop for a weedy engine is the prather 280 or octura 480,another is the p275,basicly you need a big prop because weedys dont rev high enough to spin the smaller props fast enough so you take advantage of the torque by using a big prop.Stick a walbro wa 167 carb on it and it will improve quite a bit also,thats about the best carb for these motors but anything with similar size intake would work better than the stock carbs.
http://www.hobbydepot.com.au/

I have just spent the last month in Perth Aus and the cost of parts is 50% more than the uk I went around a few shops and met with some boaters over there (and had a great sail) and they all said the same it is cheaper to buy from the uk for a lot of stuff,in Perh there is very very little available for RC boats, plenty for helli's planes and cars
there was one excellent shop that I spoke to the manager who said there was the call for boats but they Had not been able to find a boat person to work for them, which is a shame because they where a very professional outfit
http://www.perthrc.com.au/
Peter
Logged

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,502
  • Location: Blackpool
Re: Prop for deep v??
« Reply #8 on: May 04, 2010, 01:32:05 PM »

HMM thats odd as my mate lives in Perth and has no problems with finding parts for boats ,prices arent too bad either check the link out and compair prices not much difference to be honest def not 50% difference on the items i looked at.The place ive linked is a great place for gas boat gear hes well respected and reliable.
Mart
sturt 40 aus$ or 24 versus about 20 in the uk so asaving of 4 quid but then you got shipping costs.

http://www.hobbydepot.com.au/product_info.php?cPath=37_58&products_id=147

Logged

w3bby

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 773
  • Location: Helsingborg, Sweden
Re: Prop for deep v??
« Reply #9 on: May 04, 2010, 02:45:13 PM »

...strut 40 aus$ or 24 versus about 20 in the uk so asaving of 4 quid but then you got shipping costs.
Take off the VAT from the UK price for a foreign sale. Also have to look at the whole picture, 32,90 (less vat) for the SF2, Oz price for just the strut and the flex http://www.hobbydepot.com.au/product_info.php?cPath=37_90&products_id=438 is up there, 52 Aus$ for the flex...... 92 Aus = 55............

HS93 (RIP)

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,949
  • I cannot spell , tough
  • Location: Rainhill UK
Re: Prop for deep v??
« Reply #10 on: May 04, 2010, 02:46:35 PM »

HMM thats odd as my mate lives in Perth and has no problems with finding parts for boats ,prices arent too bad either check the link out and compair prices not much difference to be honest def not 50% difference on the items i looked at.The place ive linked is a great place for gas boat gear hes well respected and reliable.
Mart
sturt 40 aus$ or 24 versus about 20 in the uk so asaving of 4 quid but then you got shipping costs.

http://www.hobbydepot.com.au/product_info.php?cPath=37_58&products_id=147



http://www.heliguy.com/Extras/Radio-Transmitters/Spektrum-DX6i/?gclid=CPaJ3u3NuKECFReX2Aodxx3xEQ

http://www.stanbridges.com.au/shop.DX6I
this was of the items I priced asPaul had just bought one a aus dollar is about 60 p , you have to rember the pound has just plumeted since xmas, no doubt the person I met over there may come on and tell you more

Peter
Logged

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,502
  • Location: Blackpool
Re: Prop for deep v??
« Reply #11 on: May 04, 2010, 04:03:17 PM »

Theres allways Hong kong thats where all that hardware comes from anyway  %).
Mart
Logged

BJ

  • Guest
Re: Prop for deep v??
« Reply #12 on: May 04, 2010, 08:42:15 PM »

After a lot of thought on this i have decided to go with surface drive over submerged drive
I was originally going to go with a submerged drive however engine mounting really only will allow for a surface drive set up.

You might to take a look at http://www.modelboatmayhem.co.uk/forum/index.php?topic=23457.msg232305#msg232305 to go full surface drive. What you were thinking about the late Millar Agnew used to call "semi surface". There is nothing wrong with that - most of my boats are "semi" surface.
You may also want to use the attached chart to select a suitable turned exhaust length for your engine.
Logged

Lt. Raen

  • Guest
Re: Prop for deep v??
« Reply #13 on: May 05, 2010, 04:43:30 AM »

Thanks for that BJ sould com in handy

Martno1fan i believe that i am using th same hull as one of your boats i cant remember which build thread i saw it but im fairly sure it was yours  :-)
Also any idea of good sites from Hong Kong matrno1fan?

The prices here in aus seem very . . . ah extravagant compared to other places around the wold also the support for boats is nearly non existant in most rc stores, seems like everyone here is interested in cars and helo's not boats.

Allt thoughts and suggestions welcome

Cheers Raen
Logged

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,502
  • Location: Blackpool
Re: Prop for deep v??
« Reply #14 on: May 05, 2010, 08:15:28 AM »

Is it the wooden deep vee your building ? if so you will love how it handles its a great hull.Go full surface drive with it thats what its designed for  :-)).Heres a good source for hardware and zenoahs if you decide later you want to get one.Johnny is reliable and fast to deliver and his gear is top notch.If you email him with your order ask for a discount if your ordering a lot of stuff he might be ok with that ok2.
Mart
http://stores.shop.ebay.co.uk/Head-of-the-River-RC-specialist__W0QQ_armrsZ1
Logged

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,502
  • Location: Blackpool
Re: Prop for deep v??
« Reply #15 on: May 05, 2010, 08:17:43 AM »

Heres another pic of my old woody is it this one your doing? how about some pics.
Mart
Logged

Lt. Raen

  • Guest
Re: Prop for deep v??
« Reply #16 on: May 05, 2010, 08:30:30 AM »

Yep Mart thats the one
I will take some photos when i get the chance

Cheers, Raen
Logged

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,502
  • Location: Blackpool
Re: Prop for deep v??
« Reply #18 on: May 05, 2010, 10:14:21 AM »

You will need something to hold the tube near the engine ,either a t bar or use a plywood one,just a slot in some ply glassed between the rails works.Its just to stop the tube moving  really,silicone the tube in place at the transom to seal up the hole and fix it to the plywood at the other with  silicone .A zip tie at the motor side will stop the tube moving back till the silicone sets and its extra insurance too i suppose.Just remember its easier to take out if required if you use silicone or a t bar setup rather than glassing the tube in.What are you using for servos? you will need a high torque one for the rudder,standard is ok for throttle.Im asuming your making your own mounts for the engine? ,be sure to use rubber dampers if you are.What motor are you using?,the collet might not fit your output shaft? ,you can use a square ended flex if your using a trimmer type engine that has the square hole?.If not you will need to find a collet with the correct threads,i used a cmb .90 colett for one they have the m8 thread same as my weedy engine had.My first one had the square setup so then i had to use a ferrule to attach the cable to the shaft at the prop end using silver solder,you can also use loctite retaining compound for this.
Mart
Heres a pic of a typical ferrule setup.
Logged

Lt. Raen

  • Guest
Re: Prop for deep v??
« Reply #19 on: May 05, 2010, 11:02:09 AM »

The motor is a 25cc one from a blower vac with a drive shaft ending in 5/16 UNF threaded rod. so before ordering the collet i will email the supplier and make sure he has what i need.

As for servos i havent given them a great deal of thought
am looking at this: http://www.rchobbies.com.au/store/product_info.php?cPath=506_32&products_id=50060&osCsid=f850bba4a24216cd9a900aa0b3e7a826 for a radio and was going to choose a servo once i had the prop shaft/ engine mounting sied of things better organised
a high torque servo like this? such as http://www.rchobbies.com.au/store/product_info.php?cPath=506_60&products_id=14717&osCsid=f850bba4a24216cd9a900aa0b3e7a826
electrics might take a while as once i have the surface drive hardware i have to do some glassing as well as save some more money for the radio gear. :embarrassed:

with the flex cable that i listed do i need a ferrule as it appears to end in a stretch of unthreaded bar for the prop, or is the ferrule meant to ensure it doesnt stretch the cable pulling the prop away from the strut?

The T-bar you talk of i should be able to make out of spare ply or aluminium.

will take some photos 2moro after uni to make things clearer

Raen

Logged

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,502
  • Location: Blackpool
Re: Prop for deep v??
« Reply #20 on: May 05, 2010, 11:12:37 AM »

The ferule is only needed to atach the flex to a  stub shaft if your using the square end at the engine.If using the collet at engine you can just buy a standard round flex setup.As for radios if you want 2.4 then id go with the futaba fasst system that hops from channel to channel not just between two.The latter dont like water and can be a problem especially in fast gas boats,so if you want 2.4 go with the futaba fasst  :-)).I use the old 6ex futabba fasst system that was designed for helis and planes and its great,you can pick those up second hand or theres a newer model out now.For servos go for one with metal gears if you can for the rudder.
Mart
Logged

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,502
  • Location: Blackpool
Re: Prop for deep v??
« Reply #21 on: May 05, 2010, 11:16:13 AM »

Logged

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,502
  • Location: Blackpool
Re: Prop for deep v??
« Reply #22 on: May 05, 2010, 11:25:23 AM »

Just a bit of info on the flex cables,what happens is under load they shrink a bit so you need to leave a gap of arround 1/8-1/4" between drive dog and strut hub.If using the square setup with ferrule this wont matter as the cable floats inside the square hole at the engine end.As your using the collet setup that holds the flex firm you will need the gap between dog and strut to allow the cable to shrink a bit without binding on the strut.Look forward to the pics of your boat  :-)).
Mart
Logged

Lt. Raen

  • Guest
Re: Prop for deep v??
« Reply #23 on: May 06, 2010, 06:44:47 AM »

Ok finally got some shots of the boat. its not particularly pretty at the moment, but its the first time i have built anything like this so im quite happy with the progress so far.
At the moment m biggest prblem is that the 2 pieces of ply for the hull didnt meet at the keel so i am going to glass a keel in which shouldnt be too much hassle, however, i want to work out the running gear before i do this part.
Comments welcome  :}



Logged

martno1fan

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,502
  • Location: Blackpool
Re: Prop for deep v??
« Reply #24 on: May 06, 2010, 09:18:57 AM »

Not sure why the ply didnt meet at the keel,usually you glue it up starting at the transom and work forward,are you sure you had the two pieces the right way round ?.The problem i see looking at yours is the motor is high maybe rasing the sides at the rear would have been a good idea,thats what i did on mine.I raised the sides up at the rear to the same height as the highest part of them.Im sure you will be ok but when slowing down you may get backwash swamping the boat so dont slow down suddenly lol.Did you use rubber dampers on the motor mounts?.
Mart
Logged
Pages: [1] 2 3   Go Up