NQD PX-16

Started by CB90

14 updates 81 likes 29 comments
CB90 #11 of 15

NQD PX-16

Hi Shipmates,
Having a few days off work has enabled me to play.

I cut back the prop shafts as I wanted to at a collet around the flexi shaft, you may wonder why, well if the coupling fails for what ever reason it will stop you losing your flexi shaft and propeller.

I painted the hull a lime green, added the water cooling hoses in blue, drilled the transom for the rudder linkage bellows and drilled holes for 4 water outlets two per side of the boat, then connected up all hoses.

Soldered connectors on the two ESCs and tested motors and ESCs, (note disconnect positive + of one of the ESCs stops both BECs powering the system.)

Kind regards
Roy
Liked by AlessandroSPQR and MartinW and
5 comments
  1. BOATSHED
    Captain
    Hi CB90
    I went back onto that site, I made them an offer and I have a pair of those nice propellors on their way to me. Only trouble now is when they arrive (it's says about 18-20th June I'm a Bit dubious from China) I don't know when I will be able to get to use them.
    Liked by Len1 and Peejay
  2. CB90
    Captain
    Hi BOATSHED,

    You should get them in about a month max.

    I have the same problem finding suitable water, my club is about 35 miles away.

    Regards
    Roy
    Liked by Len1

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CB90 #12 of 15

NQD PX-16

Hi shipmates,

Servos
A change of heart with the single 20kg/cm servo the arm is large and needs an extension, thus even a 20kg will have a much reduced torque at a distance of around 6cm.
By doubling the distance of the servo arm, we’ve halved the torque
Force = Torque of servo (20kg at 1cm) / distance in cm
20kg at 1cm
10kg at 2cm
3.33kg at 6cm this may not be adequate for two 4in rudders (part submerged)

Thus I may revert to two 20kg servos instead of one that is over reaching.

Dual brushless
Dual brushless motor control is can be a problem even if using same 2x motors and 2xESCs, a 'Y' cable was not the answer for me, and one motor started turning before the other and hence run faster.

I had to scrap that idea, and the answer was to use a more complex radio gear, a transmitter with built-in mixer(s)
I had a spare 'Flysky' i6 and the following video showed me how to set it up.
note. the offset shown in the video varies considerably between setups mine was 4, his was44.
Liked by pressonreguardless and Peejay and
4 comments
  1. LewZ
    Admiral
    Hello Roy (CB90)... exactly what I was thinking. It would be very hard to find a simple setup to synch two motors with the variables involved which include not only the motors themselves, but the linkage all the way down to and including the prop.
    I find it much easier to the "original setup" you had in your photo and adjusting the boats direction running straight by trimming the rudder. In most cases we have a limited distance the boats can travel straight. Interesting conversation👍.

    Lew
    Florida 😎, USA😍
    Liked by Peejay and Len1

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CB90 #13 of 15

NQD PX-16

Hi Shipmates,

Replaced a bolt in the rudders with a plastic bolt this is a deliberate weak point, in-case the rudders hit a log or submerged item, thus allowing the rudders to lift up and not rip off the transom.

Added various stickers and a name of 'Catalyst'

Currently working on a secondary inner water proof hatch.
and touch up black portion of the boat.

Regards
Roy
Liked by Peejay and Len1 and
2 comments
  1. BOATSHED
    Captain
    CB90
    My nice new brass propellors arrived today, earlier than predicted. I am very impressed. What a great service from them. I would definitely buy from them again. Thanks again for the informattion on where to buy them
    Liked by Peejay and Len1

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CB90 #14 of 15

NQD PX-16

Hi Shipmates,

I've added a internal cover that will be taped down, made of 1mm clear Perspex.

Put in the original receiver plastic box, now with a Flysky receiver and other cables in it.

Original hatch will also be taped down.

Regards
Roy
Liked by Len1 and Commodore-H and
1 comment

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CB90 #15 of 15

NQD PX-16

Hi Shipmates,

First run was successful, it could keep up with a racing mono, which looked expensive.

There was some problems:
The battery did not last long (singe 3300mah) which I think may be duff as when it arrived it had only 8v o/p this is a 14.8v battery so not good, I managed to charge it but it only lasted about 3 mins.

The boat leaked internally, due to leaking water jackets, this is because the motors are ribbed so I have sealed them with some epoxy resin at ether end of the jackets.

Next project is
A 29in Flying fish up grade.

Regards Roy
Liked by Commodore-H and Peejay and
2 comments
  1. BOATSHED
    Captain
    Hi CB90,
    Where did you get the Flying fish from? did you buy it new or was that another off of Ebay or somewhere else?
    Liked by Commodore-H and Peejay and

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