* THE FORUM FOR ALL THOSE INTERESTED IN BUILDING AND OPERATING MODEL SUBMARINES *



Join the AMS - Registered Forum users can become members of the AMS and it's free ...... To join register on the forum first then follow the forum link to our membership form which is on our website


For further details of any events shown here also see the "Shows and Events" section on the forum

Thanks for notification of events and keep 'em coming!

.

,
,
.

. ,

;:

,./
.
.Model Boat Convention (Exhibition), 24,25 August

.

. Bournville Dive-In (2) MBC, 15th September

,,,,

Barrow in Furness MBC regatta and submarine event, Sunday 22nd Sept 2019,10am

Who is online?

In total there are 5 users online :: 0 Registered, 0 Hidden and 5 Guests

None


Most users ever online was 94 on Tue Aug 13, 2019 2:03 am

Latest topics

» upgrading the SSY 1/96 ALFA kit
Subs with twin props - alignment EmptyYesterday at 12:53 am by merriman

» Thank You To Grantham Model Boat Club
Subs with twin props - alignment EmptyTue Aug 13, 2019 5:39 pm by timgarrod

» Grantham Car pass
Subs with twin props - alignment EmptySat Aug 10, 2019 7:56 am by david f

» U3008 brass plaque
Subs with twin props - alignment EmptyWed Aug 07, 2019 1:04 pm by warspoils

» New Owner of Sheerline Sub's
Subs with twin props - alignment EmptyWed Aug 07, 2019 9:18 am by david f

» Pinger 3 - Distance measurement (Triangulation, Transponders and Clocks on Board)
Subs with twin props - alignment EmptyWed Aug 07, 2019 9:12 am by david f

» Assembling the excellent Scale Shipyards 1/96 SSBN, USS Daniel Webster
Subs with twin props - alignment EmptyMon Aug 05, 2019 5:00 pm by merriman

» John Lambert Plans
Subs with twin props - alignment EmptyThu Aug 01, 2019 2:03 pm by salmon

» Norwich MBC Submarine, Boating & Sailing Weekend, 2019
Subs with twin props - alignment EmptyWed Jul 31, 2019 11:37 am by david f

Statistics

Our users have posted a total of 10893 messages in 1786 subjects

We have 818 registered users

The newest registered user is AlvaroAlc

    Subs with twin props - alignment

    david f
    david f
    AMS Treasurer

    Posts : 2039
    Join date : 2010-11-10
    Age : 69
    Location : Cumbria

    Subs with twin props - alignment Empty Subs with twin props - alignment

    Post  david f on Wed Nov 17, 2010 4:28 pm

    The U class I am having a go at building is my first sub with twin screws.

    Usual practice in submarines seems to be that the props are at right angles to the direction of motion. Does anyone have a feel for what happens if the props are angled slightly up or down? Is this important? Does it give you bows up/bows down operation?
    avatar
    Tom(ADMIN)
    AMS Forum Owner

    Posts : 2997
    Join date : 2010-11-05
    Age : 59
    Location : Nevada, USA

    Subs with twin props - alignment Empty Re: Subs with twin props - alignment

    Post  Tom(ADMIN) on Wed Nov 17, 2010 4:35 pm

    I wouldn't have thought it would make a great deal of difference to a relatively low powered sub, David...I do recall back in my multi-racing days prop shaft angles were important when using a high revving, high speed motor like a .65 glo motor, and even more so in the world of hydro racing, but I don't think you'd notice much difference in a sub.

    I stand to be corrected though...
    david f
    david f
    AMS Treasurer

    Posts : 2039
    Join date : 2010-11-10
    Age : 69
    Location : Cumbria

    Subs with twin props - alignment Empty Re: Subs with twin props - alignment

    Post  david f on Thu Nov 18, 2010 12:39 pm

    The reason I'm asking is that experience tells me that it is very difficult with a new model to get the right combination of motor, gearing, prop diameter and prop pitch to get the right current draw, model speed etc.

    Hence a bit of "wriggle room" with prop diameter is useful but twin screws don't give you much scope to increase the prop diameter before you start to foul the hull, rudder, stern planes etc (I'm thinking of the U Class.)

    So a little bit of scope to change the angle of prop shaft relative to the subs axis would be useful. So I hope you are right. Because yes we are not talking racing models here.
    avatar
    Tom(ADMIN)
    AMS Forum Owner

    Posts : 2997
    Join date : 2010-11-05
    Age : 59
    Location : Nevada, USA

    Subs with twin props - alignment Empty Re: Subs with twin props - alignment

    Post  Tom(ADMIN) on Thu Nov 18, 2010 12:41 pm

    That's one reason why I like boats with single props...
    david f
    david f
    AMS Treasurer

    Posts : 2039
    Join date : 2010-11-10
    Age : 69
    Location : Cumbria

    Subs with twin props - alignment Empty Re: Subs with twin props - alignment

    Post  david f on Fri Nov 26, 2010 4:21 pm

    I have spoken with Nigel about this who indicates that the alignment is important.
    It is similar to the "thrust line" concept in model aircraft.
    Probably less significant in model subs but Nigel suggests that if you imagined extending the prop shaft to the bow , the line would be close to the bow at the waterline/
    avatar
    Tom(ADMIN)
    AMS Forum Owner

    Posts : 2997
    Join date : 2010-11-05
    Age : 59
    Location : Nevada, USA

    Subs with twin props - alignment Empty Re: Subs with twin props - alignment

    Post  Tom(ADMIN) on Fri Nov 26, 2010 4:52 pm

    I guess you could align the props and shafts correctly and then use flexible couplings to hook the shafts to the motors? I always use high quality silicone tubing now for connecting prop shafts to motors...easy to use, easy to replace and very adaptable to differing angles between motor and prop shaft.
    david f
    david f
    AMS Treasurer

    Posts : 2039
    Join date : 2010-11-10
    Age : 69
    Location : Cumbria

    Subs with twin props - alignment Empty Re: Subs with twin props - alignment

    Post  david f on Mon Jul 04, 2011 1:01 pm

    Just adding to this, now that Dzik is complete.

    The props in the end were fitted parallel horizontally but the shafts were inclined slightly upwards, vertically - if you see what I mean.

    It doesn't seem to have created any problems - the bow does not dip when you throttle up etc. etc.

    This is my first experience of running a sub with twin props so some videos of using twin channel mixing to aid stationery and under way turns:

    https://www.youtube.com/watch?v=oy7Wxdo13bs

    https://www.youtube.com/watch?v=CQfYg0AbKAU
    avatar
    Tom(ADMIN)
    AMS Forum Owner

    Posts : 2997
    Join date : 2010-11-05
    Age : 59
    Location : Nevada, USA

    Subs with twin props - alignment Empty Re: Subs with twin props - alignment

    Post  Tom(ADMIN) on Mon Jul 04, 2011 1:14 pm

    That's very impressive David, although I'm not too sure what that yacht skipper thought of you chasing him through the turn in the second video...
    thegrimreaper
    thegrimreaper
    Guest

    Posts : 119
    Join date : 2010-12-01
    Age : 59
    Location : Ellesmere Port

    Subs with twin props - alignment Empty Re: Subs with twin props - alignment

    Post  thegrimreaper on Mon Jul 04, 2011 3:36 pm

    Richard(Admin) wrote:That's very impressive David, although I'm not too sure what that yacht skipper thought of you chasing him through the turn in the second video...

    Yacht Capt probably thinking Dave looking for a firing solution,bloody targets getting in the way.

    nice video's David


    Mark
    david f
    david f
    AMS Treasurer

    Posts : 2039
    Join date : 2010-11-10
    Age : 69
    Location : Cumbria

    Subs with twin props - alignment Empty Re: Subs with twin props - alignment

    Post  david f on Tue Jul 05, 2011 8:20 am

    Yes,I only just noticed that when I was looking at the videos. With the mixer I can now do the marine equivalent of Harrier "viffing" to avoid impacts!

    Still Sunday morning at Barrow is as nothing compared with the "Free sailing session" at Alfold.

      Current date/time is Fri Aug 23, 2019 5:47 am