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[Martin13]

Hi John,

Initially your thoughts  freaked me out, but after much procrastinating, have an idea on how to modify "P" brackets.
I will have some new bearings made up (probably can use bearings from surplus shafts) with a short sleeve and insert into existing "P" bracket housing. I will then remove the flat plate and make up a new vertical section 3/4" longer as per your suggestion..

I gave it a lot of thought last night and agree with you in that the "P" bracket protruding through the hull will provide a lot more strength and load displacement. I will also fit another bearing inside between hull entry and motor coupling - will probably have to make a ply support somewhere inside with the bearing installed.

I will make up a sample "P" Bracket today with bearings etc and post more pic's for your perusal..

Martin doon under

[Martin13]

Well, got stuck into it today to make up some new "P" Brackets - lucky I have plenty of brass about.

But first, the picture below explains the process in how "Prototype 1" brackets where made and assembled. Note, the Brackets were CA glued together for trial purposes only.

Martin doon under

[HS93 (RIP)]

Can you get hold of any tufnol, if you can fit some for bearings on the P brackets you will not have any problem lubricating them as brass can wear quick when not lubricated. just a thought


http://www.tufnol-rod.co.uk/


Hs93

[Martin13]

The brass plate is 3mm thick whilst the bearing housing being 13mm diameter with an 8mm hole bored through on a friend's lathe.
"Prototype 2" brackets were made as per Bluebird's suggestion. The bottom plate was removed and a longer vertical section made up to protrude  through slots in hull about 15 - 20mm.
I found that a Dremel tool was ideal for cutting the Brass section - best purchase ever.

The bearing housing (as I had a few spares made), had the 8mm hole to allow shaft tube clearance and due to shaft only rotating in housing - bearings need to be fitted. I removed the bearings from surplus prop shafts and cut a small section of 8mm tube to fit between the bearings. This assembly was then placed into the housing with shaft and prop installed.
The idea now being that the prop tube will protrude the bottom of the hull by about 15mm and shaft supported at this point by a bearing.

Martin doon under

[Martin13]

Can you get hold of any tufnol, if you can fit some for bearings on the P brackets you will not have any problem lubricating them as brass can wear quick when not lubricated. just a thought


http://www.tufnol-rod.co.uk/


Hs93

Thanks on your input HS93 - Personally, I am not familiar with Tufnol and thanks for the link - will remember this stuff.

I discovered a small problem when using the existing bearings in that the bearing closest to the hull, had a tendency to work its way out of the housing. I am now having new bearings made up (oil impregnated Phosphor Bronze) with a flange. The new bearings will fit into the housing quite snuggly (may use Loctite) and butt up against the end of housing - This should stop bearing from working its way out.

Will see how this works out in the next couple of weeks.

Martin doon under

[HS93 (RIP)]

I have just posted a picture of yours with a mod, add a collar to stop the thrust from the props pushing on the skegs, your mate with the lath will prob knock then up in 2 min just a grub screw to hold them , in fact some model shops sell collars that you may be able to drill out   the collar is in red. it help the motors as well as they are not getting any end load.

Hs93

[Martin13]

I have just posted a picture of yours with a mod, add a collar to stop the thrust from the props pushing on the skegs, your mate with the lath will prob knock then up in 2 min just a grub screw to hold them , in fact some model shops sell collars that you may be able to drill out   the collar is in red. it help the motors as well as they are not getting any end load.

Hs93

Thankyou again Sir. What a simple fix.

Martin doon under

[John W E]

well hello there G'Day Martin and Hi there Peter - long time no speak -

Spoke to our friend last night Peter (Martin (Seaspray) ) anyway this is deviating ... just as a thought the 'P' brackets are meant to take the thrust of the propeller.  The reason for this is, if there is any great distance between the 'P' brackets and the stern tube; if the 'P' bracket does not take the thrust and the end of the stern tube takes the thrust as in where the collar is fitted - the propeller shaft will bow and buckle not to meantion vibrate.   So, it is therefore, best to keep the thrust of the propeller onto the backface of the 'P' bracket - and that is why I suggest we take the vertical leg into the hull - araldite (epoxy) it - into the inside of the hull to spread the load.

If you have a look at the photographs you will see there is no thrust bearing on the outside of the stern tubes.

The other thing Martin doon under - remember the bearing and housing on your 'P' bracket is to be shaped similar to a 'bullet' for the sake of water flow and to prevent cavitation.

aye
john e
bluebird

[Martin13]

well hello there G'Day Martin and Hi there Peter - long time no speak -

Spoke to our friend last night Peter (Martin (Seaspray) ) anyway this is deviating ... just as a thought the 'P' brackets are meant to take the thrust of the propeller.  The reason for this is, if there is any great distance between the 'P' brackets and the stern tube; if the 'P' bracket does not take the thrust and the end of the stern tube takes the thrust as in where the collar is fitted - the propeller shaft will bow and buckle not to meantion vibrate.   So, it is therefore, best to keep the thrust of the propeller onto the backface of the 'P' bracket - and that is why I suggest we take the vertical leg into the hull - araldite (epoxy) it - into the inside of the hull to spread the load.

If you have a look at the photographs you will see there is no thrust bearing on the outside of the stern tubes.

The other thing Martin doon under - remember the bearing and housing on your 'P' bracket is to be shaped similar to a 'bullet' for the sake of water flow and to prevent cavitation.

aye
john e
bluebird

G'Day there matey,
Good to see that I woke you up

How is Martin (send a pm about Martin)

When I get the correct setup for the "P" Brackets and Sliver Soldered, then I will shape the leading and trailling edges as per the photograph.
The bearing that worked its way loose was the one at the "P" bracket housing (opposite end to prop). This bearing will need to be made with a flange and be of a fairly tight fit

Hope that makes sense.

aye Martin doon under

[Martin13]

Well, finally got "P" Brackets silver soldered, edges filed down like a bullet and all cleaned up. Slots made into hull to fit "P" brackets and shafts and tubes temporally fitted to allow correct aligned of brackets before epoxying into place.

3mm ply added to inside of hull for extra strength to accommodate P & S "P" brackets and shaft tubes

Martin doon under

[Martin13]

After the epoxy had set, I then cut in half the original "P" bracket base plates and glued either side of the "P" brackets as in the full scale boat.

Thanks to the input of Bluebird and HS93:-
If you look on the hull, you can see the new "P" bracket bearings I had made up with a flange. These will be installed into the "P" brackets with a small dab of Loctite to allow removal should and when the bearings wear. This setup will also remove the need to place a collet on the shaft behind the bearing.

Martin doon under

[Martin13]

Now that the shaft tubes will only be protruding the hull by about 1/2 inch, the P & S tubes will need to be braced inside the hull. On one of the formers I added a 3mm brace either side of the formers to support the shaft tubes..

Martin du

[Martin13]

My new Center shaft finally arrived (520mm long) at last and now can install into the hull. I placed the tube into the hull and measured the height it needed to be above keel for motor fitment and alignment before cutting off excess tube. Bearing fitted into tube and shaft also fitted..

Martin

[Martin13]

With the center shaft being so long, I placed an 8mm wedge beneath the shaft, between where the tube enters the hull and the former. I then very lightly epoxied the tube to this support. The P & S tubes were fitted in a similar fashion except they rested  on the ply braces I fitted earlier.

Once I was happy with the locations and alignment of the shaft tubes, I then used P38 around the tubes at the hull and between the braces inside the hull - I'll use the Dremel and clean up at a later stage.

Martin du

[Martin13]

Once the P38 had fully cured, I checked again that the motors would fit correctly with a ply base plate when fitted. As you may have noticed, the center motor will be set further towards the bow than the P & S motors. This was due to the acute angle of the center shaft and also the close proximity to outboard motors. The shafts are 88mm between centers and the motors are quite large with mounting brackets and cooling coils fitted.

I then turned over the hull and used P38 on the tubes and "P" brackets...

Martin du

[Proteus]

Are you fixing the bearings as in picture with the bush flange forward   BB P10110126 ?

 Bluebird

 I think martin said in a post that the shafts are 5mm turned down to 4mm how will a 5mm shaft  " bow and buckle not to meantion vibrate".    the likes of  http://www.gsitek-props.co.uk/products.asp?cat=19   supplied  thrust collars with my shafts , and so did his predecessor.

Proteus
 

[Martin13]

Once the P38 had fully set, I began to file and sand away excess P38 filler. In my over enthusiasm to see this task completed, I managed to put in some deep scratches into the hull.

Will keep flairing in P38 and sand off to a smooth finish but in the meantime will ponder whether to use P38 or one coat of resin to fill scratches.. Ho Hum >:(

Martin du.

[John W E]

[ ponder whether to use P38 or one coat of resin to fill scratches.. Ho Hum ]

P38 

[DickyD]

Coming along nicely Martin itchy doon under 

[Martin13]

Are you fixing the bearings as in picture with the bush flange forward   BB P10110126 ?

 Bluebird

 I think martin said in a post that the shafts are 5mm turned down to 4mm how will a 5mm shaft  " bow and buckle not to meantion vibrate".    the likes of  http://www.gsitek-props.co.uk/products.asp?cat=19   supplied  thrust collars with my shafts , and so did his predecessor.

Proteus
 

Proteus,
The flanged bearings will be fitted as per the photo.

As for the shafts, due to tubes being cut down to protrude only 1/2 inch from hull, it was decided that a 5mm shaft was unnecessary since a bearing would be fitted at the end of the tube. The other problem was that I made everything to suit an 8mm shaft tube and that with a 5mm shaft, would make the bearings very thin indeed. (something I did not think about earlier).

By the way, I will be using the G-Sitek running set on my Type 22 build. With Brave Borderer at 1:16th scale - everything has to be made to suit.
But thanks for your comments and please make more as you see fit - it all helps this little Black Duck

John, thanks for that, P38 it is - I always need somebody to make up my mind for me or at least that's what swmbo reckons ::) ::)

Dicky, I think you will complete at least 5 models before I finish this one

Martin du

[Martin13]

I NEED YOUR INPUT

Shortly I will be starting construction of the Transom Shelf and the adjustable Transom Flap. I know how to build the Transom flap and the setup for the hinge mechanism and fixing to the transom, but have run into a small problem.

There are two arms that come up from the flap and enter the transom just below the shelf at the stern then somehow connected to a servo. The transom Flap needs only to be made adjustable by a maximum of 5 degrees up/down.

Do any members have ideas on the mechanism/linkages to the servo in order to achieve the desired result, keeping in mind that the rudder linkages are in the same area.

Sketches of your ideas would be most appreciated as I can be a bit thick sometimes ::)

Martin doon under

[John W E]

good morning Martin - it is about time you sent us some sunshine from Australia there my mate - I am sure your winter sun is much better than our summer sun 

Here is a scribble of one way you can do your transom flap.   If you have a look part B is a brass tube which goes through your transom at an angle - obviously there are 2 of these - one either side of your centre rudder post.  Through the centre of these brass tubes you have your push rod, something like 1/16 stainless steel or 1/16 brass rod - thread at both ends.  One end you have the linkage coupling to your flap - and, the other end is a linkage coupling which fits into item C .   Item C has a slot cut into it.  The length of this slot will be trial and error    the arm C is securely fixed to a shaft which runs transversely across the back of the transom and is fixed to supports which are located on the transom.    Just off centre there is 2nd cam  D  this in turn is connected through a linkage rod to a servo.     Now, where the linkage rod connects to the servo; the closer the rod is to the centre of the servo horn - the less movement you will get.  This is turn will give you less transom flap movement.

Now connect the servo to a 'Y' lead from your centre speed controller so therefore as you accelerate the motor; the servo in turn operates at the same ratio as your speed controller.  Therefore gradually pushing the flap down at the higher speed.  Food for thought, plenty for you to practice with 

Just one idea of many no doubt Martin doon under there.

Aye
John e
bluebird

[Martin13]

John,

What an absolutely brilliant idea :)   Well explained and a great drawing.

. I like the way in which you have the arms entering the transom - just like the full scale boat. Your linkages etc are similar to the one's I use on my RC gliders which will simplify the setup.

Good idea connecting servo via a "Y" lead - I did not think of that

Thanks again John in taking the time and producing a great sketch.

Martin where it's still sunny in the middle of winter where's the rain

[Peter Fitness]

Winter Martin???   It was 25 degrees Celsius here last week, although it's been down to single figures overnight.

Your build seems to be coming along nicely, and the gents on the forum are being very helpful - as always.

Peter.

[Martin13]

Time for an update.

Finally got some paint and sprayed the hull with primer/filler grey - now it starting to look like a boat.

Next step was to make up the framework/supports for the engine mounts. In this area I decided to use 8mm plywood scraps and angled the supports to aid motor and shaft alignment. After all three supports were constructed, I needed to brush on one good coat of resin in the rear section of the hull as this would be difficult to do once the motor base plates were epoxied to the supports.

Martin no longer itchin doon under :)