My eezebilt PT boat

[David StillParticipant @davidstill31471]

I like it seems many others have decided to build this between projects as a simple no frills build as yet no problems and fun working in balsa I'm doing a 28" model as it will be running in the local estuary.

I am still building the hull and installing the running gear progress is steady but no issues as yet I have double skinned the hull bottom for a little more durability.

Dave

[David StillParticipant @davidstill31471]

[Dodgy Geezer 1Participant @dodgygeezer1]

…I see you're using the 'notched bow skin' technique popularised by Les Rowell.

How big are the unsupported gaps between the bulkheads? I find that 1/16" balsa tends to sag after a while when the gaps are bigger than about 4". But of course if you are using double-skinning the gaps can be bigger…

[David StillParticipant @davidstill31471]

I have kept the gaps the same but the double skin has made it quite solid I will do the sides the same way.

Dave

[David StillParticipant @davidstill31471]

Prop shaft epoxied in the rudder post next.

Dave

[David StillParticipant @davidstill31471]

Not to much progress recently I found an old Acoms servo that works fine so I'm using that, the double thickness skin seems plenty good enough.

I have added the spray rails and it's had an initial couple of fills and rub downs I've done two coats of dope and waiting now for a varnish coat to dry before rubbing back.

[Dodgy Geezer 1Participant @dodgygeezer1]

Looking good! You can do a much more detailed superstructure at that scale….

What size motor, prop and batteries are you expecting to use? I found that the original was so light that even the smallest brushless on 7.2v was enough to push it at a good scale speed. In fact, I had to trim the rudder to stop the turns getting too tight at speed. With the size of rudder you have I suspect that you won't need much throw at all at speed, which may make it a bit harder to manoeuvre when going slowly…

[David StillParticipant @davidstill31471]

As I am trying to keep to the school boy ethos it won’t be doing slow! I could mix in a throttle rudder mix so more throttle less rudder. I have used a spare brushless I bought for a glider which I think is around 170w on a 3s so I may only go 2s I have a 35mm 3 blade prop.
I’m looking forward to scratch building the fittings.

Dave

Edited By David Still on 26/06/2017 19:02:39

[Dodgy Geezer 1Participant @dodgygeezer1]

Throttle mix sounds like a good idea. I might try that on mine. The point is that full rudder at speed can almost put a boat on its side, so the throw needs to be slight, while when manoeuvering to come alongside the shore at slow is going to need full rudder…

[Dave MilbournParticipant @davemilbourn48782]

The point is that full rudder at speed can almost put a boat on its side, so the throw needs to be slight, while when manoeuvering to come alongside the shore at slow is going to need full rudder…

Now this may come as surprise to some, but these days we have what's called "proportional control". It's not really very exciting – it means that if you just want a little bit of rudder – for example, at full speed – then you only move the sticky-up steery thing a little way. If you are manoeuvering at low speed then you move it a lot further. It isn't a switch – contrary to what 90% of model boat skippers seem to think.

Clever, eh?

You read it here first, folks.

DM

[Charles OatesParticipant @charlesoates31738]

WOW. That sounds great, time to change my Reed set!😂

[Dodgy Geezer 1Participant @dodgygeezer1]

Posted by Dave Milbourn on 29/06/2017 23:24:49:

The point is that full rudder at speed can almost put a boat on its side, so the throw needs to be slight, while when manoeuvering to come alongside the shore at slow is going to need full rudder…

Now this may come as surprise to some, but these days we have what's called "proportional control". It's not really very exciting – it means that if you just want a little bit of rudder – for example, at full speed – then you only move the sticky-up steery thing a little way. If you are manoeuvering at low speed then you move it a lot further. It isn't a switch – contrary to what 90% of model boat skippers seem to think.

Clever, eh?

You read it here first, folks.

DM

Some people seem to have a need for dual rate controls – otherwise why would the fly-boys have them? I tend to run slow-speed control on the sticks, and high-speed turns just on the trims. That provides much more realistic turns than trying to give a slight nudge to the main controls….

[ashley needhamParticipant @ashleyneedham69188]

I was going to add words of wisdom but the argument can go either way. After writing several posts and then re-writing them I have decided not to wisdomfy a posting.

​BUT

​I sort of like the trim method but know that in a "where on earth did that duck come from" moment I would want my thumb on the twiddly stick rather than the trimmer….SO….I would be in favour of trying to make the boat stable at speed and alter rudder sizes and throw accordingly. A small rudder in the prop-wash should be fine for slow speeds when using a quick burst of power, without being too much at speed. ????

​Ashley

​

[Author]

Posts