Hello ColinH.

If there is anything else that I can help you with in your build Duncan, please do not hesitate to ask.
You mention the bending of the skins, the bottom skins go on ok, but putting on the side skins, there is a hell of a twist to get them on the prow, I resorted to screws, after pins would not hold it.

Cheers, Pete😊

Thank you Pete for you advice.

Glad to hear you made the show at Bury, regarding power, I find that a 400 brushed motor does the job perfectly, either using 6 cell Nmh, of 2 cell Lipo, it has a great hull which cuts through the water really easy,
hope you have much enjoyment building her.

Cheers, Pete😊

Thank you to Rookysailor and Peewit83 for your advice. I was at the rather wet show in Bury and that is where I bought the kit. I did speak to Paul but I just wanted some other ideas rather than using LIPOs and brushless motors. Useful to hear about fitting the transom after putting the servo in. I do have a small 15gm servo which from Roy's advice will probably be big enough. I just thought if it is mounted flat on the keel (as per an earlier photo) if the servo fails for any reason it will be easier to replace rather than one tucked up in the corner.
Was it the bending of the skins which was a problem when fitting?
Thanks guys D

Hi
My son and I built our version of Flying Christine 2 a while back. It wasn’t that easy! The rudder operation has always been suspect . I cut a hatch in the aft deck to allow easier access.the servo is mounted in the cockpit. Careful
Ballasting is necessary too
Good luck!

Hope you were at our open day at Bury Model Boat Club on Sunday, as Paul the owner of HA Kits was there with his stand, he would have answered all your questions.
I have built the Flying Christine II, she is a lovely boat to build, putting the skins on was the hardest bit, regarding the rudder, I used a standard size servo, but make sure you connect everything regarding the steering, before you glue on the transom, and best of luck with everything.

Cheers, Pete😊

Hi Duncan you can always fit a smaller servo. There are marginally smaller ones at 12 grams then 9 grams and that would work as well.
You get 0.5 kilograms at about 1 cm so enough power for a rudder with a 9 gram servo and they are cheap as well.

Roy

Hi Roy, yes it is shoehorned into a tiny space. I think it would have to be fitted before the decking is applied! I've seen another solution in which the servo is installed on it's side along the keel.😊

Glad I was able to clear up this explanation with the help of the photo.
All the best D

Thank you very much for the clarification Duncan and especially for the photo. I just couldn't understand. Now it's clear to me.
I prefer to put the engine as far aft as possible because in this way the propeller shaft is shorter (and this has many advantages). However, I realize that, if it is not possible to position the engine low, then it is better to lengthen the propeller shaft in order to reduce the inclination. Very good.

Hi Duncan and there you have a way to fit in the rudder servo.
Roy

The motor is not quite in the bow but forward of centre because of the large sunken cockpit and also the location of the prop shaft. The photo is of one that another owner has built.

Why put the engine in the bow though? Who knows?

Thanks for the reply Roy.
Yes I can imagine that, indeed, 122 grams placed in the bow can affect more than in the stern or amidships and prevent planing. Right.
I lack experience in this field.

Hi re weight differences. The motor will be at the front of the boat and will have to be lifted up as the boat tries to plane.

Also 122 grams is around the weight of the receiver plus a rudder servo and maybe a very small esc.
So this weight saving is worth doing, I am not saying a 600 would not work but the battery will have to supply that much more power so the lighter you make the model the longer it will run.

I have run 3 fast boats with both above options. All 3 planed nicely the one with the 380 had a 1 : 2 reduction gearbox and on 6 cells was almost uncontrollable. It is 16 inches long (Huntress) and in my harbour for reference and before battery settles down there is just 2 - 3 inches of boat in the water, she is very light in weight.

I had 2 Bobby launches with 540s in and 6 cells they were fast and we used to sail on a shallow stream, not quite a river. On one occasion one of them was seen to put a spurt on although already at full speed.

It turned out it had shed a blade of the 2 bladed prop and actually went faster!

Now I sail displacement boats and yachts, however I shall be out sailing with friends on Wednesday and have just re worked an Airboat. Now that goes fast and has a mind of its own!

Regards
Roy

I’m with Roy. A 540 with a 6 cell Nicad is always a great reliable go-to method of propulsion. I never toss out my Nicads or any 540 that could be repurposed for good cruising in another build.
👍

Hi Roy, I'll start by saying that I'm not an expert in speedboats or even planing.
I love displacement boats.
So I'm asking you this question just out of curiosity, to learn from you.

I looked at the Graupner brand (to have an example reference) and I found that the difference between a Speed ​​600 [195 grams] and a Speed ​​400 [73 grams] is 122 grams.
Do you think that 122 grams on a weight of 1.63 kg can negatively affect planing?
This is very interesting to me

1.5 Kgrms was a ball park figure just build in lightness!
Roy

Hi Roy I've just weighed it in the box and it weighs 1.63kg. Presumably with all the packaging and the wood wastage that should be fine even though there will be glue and paint to be added? D

Hi Alessandro, I proposed Speed 400 as the power is there and the motor is much less weight than the 600.

That model needs to be no more than 1.5 Kgrms to plane easily.

Roy

When using my LIPO batteries I have a device attached to the balancing wires which sounds an alarm when the battery is getting low. Is there something similar that can be used with NICAM to warn you of a low boat battery? D

Hi Duncan, I refrain from recommending engines because I always prefer to take oversized ones (in terms of power).
I would opt for an equivalent of the Speed ​​600 but I know I will attract a lot of criticism (moreover justified).
However, this could be useful for your choice:



https://model-boats.com/forum/147506

https://model-boats.com/wiki/147457

Hi Duncan yes they do need suppression. Do check if using a Speed 400 some I think are already suppressed.
I use 3 off 0.1 microfarad capacitors. One between the brushes and the other two from each brush to the body. That gets rid of most of the RF interference.

If you are using 2.4Ghtz RC then you do not need suppression but you will affect any other users on the other frequencies.

The capacitors cost pennies but check electronics suppliers you need a working voltage of 50 volts for the capacitors.

regards
Roy

Great advice Roy - thank you. With some motors do I have to worry about suppressing these brushed motors? Cheers D

Hi Duncan, any battery with more than 3000mA capacity should be OK but have a spare as well.

Your idea sounds sensible a small bow wave will look scale as well. The small motors intended for Bruma will not be powerful enough for Flying Christina.

Main thing is to keep the weight down. As a collector of motors I have a lot but the 380 is very cheap. Or perhaps the Speed 400 would suit but do not pay more than £8.50.

Hope this helps.
Roy

Hi Roy, Great to hear your advice. I had thought the 5 Pole motor just made it smoother rather than faster so thanks for putting me straight on that one! I've still got 2 of those small motors I brought for the Bruma because I upgraded these to 5 Pole because I found they didn't necessarily both start up together simultaneously. How many milliamps battery would you think would be good with the 380 motor? I want to use a brushed motor with NiCam battery. I want the bow to raise a bit but not for the boat to be too fast for an 11 year to control safely. Thanks D 😊
P.S. Hopefully I'll get Bruma finished before starting this one!!

Hi Duncan, what motors and batteries do you have? I have a similar model an old 'Bobby'. A 540 motor on 7.2 volts and a 35mm prop makes it go very fast, maybe too fast.

A 380 motor (40 watts) not a 5 pole low power one would work but with an even smaller prop 30mm, would work as well. This is due to the high speed of the motor.

Generally 20 watts maximum would drive her very nicely 7.2 volts at 3 amps load.

I do not know much about brushless but I expect others on the forum can advise.

Nice choice, will be pleased to see photos of your build.
Roy

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