Topic: 1/32 MTB PT-109 experimental project for this autumn (Read 9713 times)

Backerther · « **Reply #100 on:** December 07, 2024, 01:59:42 pm »

Derek,
You hit again interesting point of sound change about which I have been annoyed to some extent....
To tell the truth, right motor is possible the key to solve these subjects/problems.
while right motor is so smooth in revolution by fingers as well as left one.

The set-up of the pump units are I'm sure well securely done and alignment between motors and impeller shafts also
seem OK.
One point I feel anxious about is the design of setting a motor to its motor mount of the pump unit which seem a bit
unstable and unbalanced for a very high speed rev. brushless. To make the matter worse, the material of the pump is plastics which may be apt to irregularly vibrate at rather low rev. not at high rev,.

But left motor has kept on working since the set-up.

At any rate, vibration and resonance are normally clear at low rev,. and would disappear at over half throttle for my ears.

(for my right ear with a hearing aid)

Another point to cause such resonance or vibration I suppose may come from difference of calibration of ESC between the two.
I am trying to adjust the right ESC properly to be arrived soon according to the instruction manuals.

At any rate I could enjoy this pla- model jet boat to make her better for a month or so to come.

Wow.!

Backerther · « **Reply #101 on:** December 08, 2024, 02:34:08 am »

By the way, I tested the jet capability of my jet pump unit actually on the lake (not on the bathtub water) to confirm how much powerful it would show me. Since I have imagined already it would surely drive me to a terrible result to get me drenched to the skin right after starting the test in the bath room.

Oh,my goodness!

Attention even to the drain of the cooling water in the form of long and sometimes a bit linear flow not arch..

What should I represent this wake other than "this is really jet"!!??

Arno's jet of his Shannon is possibly and surely way violent than mine like rocket (not jet) like power by large brushless motors....

Backerther · « **Reply #102 on:** December 09, 2024, 05:30:48 am »

When I was watching the video carefully of my 109JP for analyzing her behavior on the water, I happened to come across unique
scenes that one or two waterfowls was observing my boat seriously to pass in front of them. Followed by consequent anger..?

Is it only me who to understand the waterfowl in that way.!!?

Apart from your understanding the scenes, it may be true that the scenes may reflect a good harmony between the boat(artificial) and the waterfowl (Nature), isn't it.?

In this sense, RC boating on the water may produce such "a byproduct" other than boating itself....???

And I may be so happy to be able to enjoy such a byproduct at home and Nature beside the lake ...

Wow!

Backerther · « **Reply #103 on:** December 12, 2024, 02:39:03 am »

Hi mates,
It was a very fine day yesterday with the air temperature of 14degrees C and around 2m/s of wind speed, slightly windy and choppy on our local boating lake as in the pics below. A bit severe for a trial run for my small pla-model boat, but this is a MTB..

There was no reason why I did not go to the site for the weather conditions at all for the third trial day.

Since I just applied some countermeasures to improve my 109JP as to meet my image of sailing performance as a model MTB.

Before actual sailing of the small boat for the lake, I checked the balance as I had reset the battery location and a small ballast as well as trimtab angle to get it slightly negative side for much better planning attitude with a higher speed capability.
The choppy lake was not cooperative with the test a bit drenching all the crews to the skin.

Compare the size of wave with the boat swinging like a piece of leaf floating on the water..!!??

Therefore, I previously inflated a rescue rubber boat for a quick response against sudden stop of 109JP due to an accident.

swiftdoc · « **Reply #104 on:** December 12, 2024, 05:54:35 am »

Photo no. 7 is just beautiful, Kiyo!

Backerther · « **Reply #105 on:** December 12, 2024, 10:09:42 am »

Thank you so much, Arno.!
Yes, that looks good to my eyes, too.

Backerther · « **Reply #106 on:** December 13, 2024, 04:31:17 am »

Hi RC sailors,
I'm so glad to be able to post such nice shots as I think they are from the trial run carried out the other day as seen below.

Trial run this time has reached the third day and I think the result is generally OK since a remarkable improvement has been
confirmed in both top speed and sailing behavior by some countermeasures taken after previous 2day trial runs.

Especially, the new negative trimtab angle seems to have largely contributed to lift the stern up by which top speed might have been increased together with a better planning attitude.

Above all, sudden stop on the water of which I was so much afraid never took place even under the choppy water conditions.!!

Sailing attitude looked as if she were sliding smoothly on the water to me thanks to the new angle of trimtabs.

Strange as it may sound to you or not, I this time have applied car wax over the semi-gloss colored hull bottom for both good speed and easy maintenance.

Nevertheless, further improvement still may continue.. Next trial is scheduled to carry out around Christmas day.

Enjoy the pics of small pla-model MTB on a bit rough surface of lake, as well as low and long jet flow generated from the twin nozzles over the water by the new trimtab angle for one reason .

swiftdoc · « **Reply #107 on:** December 13, 2024, 06:01:12 am »

I am happy that you achieved even more improvement Kiyo, well done

Please send us a photo of the trim tabs, so that we can see the angle. It will be interesting for me as well, as so far mine are set level with the hull.
Do you have any idea what has caused the blown up motors before?

Backerther · « **Reply #108 on:** December 13, 2024, 10:03:18 am »

Arno,
Here are the photos concerned with my so primitive the trimtabs set this time as slightly negative side (down side from the level with hull bottom). My PT109JP is too small to install hi-level of wireless power-driven trimtabs like yours.

So, my style of adjusting the angle of the tabs are simply dependent upon wedges to be driven between the hull and tabs which thickness is very ""angle adjuster".

See the detail in the picNo.2/3/4 below.
A wedge is able to move up and down a bit until optimum angle is found. If not done, another new wedge will do instead...Soo primitive!!!!

Pic1; Trimtabs set like this for the third day trial.
Pic2/3; The angle of the tabs set slightly negative for this third day trial run.
Pic4; You may confirm so simple a wedge.
Pic5; Very first trial run with no tabs by which bow was too high for my eyes.

The stern decks seems as low as the surface.

Pic6;The second day trial with tabs set level with hull bottom didn't show an apparent difference from the first trial in the bow attitude.

Pic7;The slightly lowered tabs might possibly have done a good job to get the stern a bit high by which the jet flow came up
a bit more over the water surface and generated more volume of jet mass contributed possibly to speed-up.

See pic1 of previous post that shows mass of jet coming out powerfully on the water surface.

As for the motor problem, I replaced the motor with a new one together with new ESC by which no problem arose in the two trial runs on the day and the motors were a bit hot right after each run.

This will be another subject for next trial.

Backerther · « **Reply #109 on:** December 14, 2024, 06:43:00 am »

And this is the video of the third day trial run that tells everything concerned with the sailing behaviour.
No need to say any more with lots of description....

It's entirely up to you how you understand the contents.

https://youtu.be/u0b118KNsbs

swiftdoc · « **Reply #110 on:** December 14, 2024, 07:20:49 am »

That looks like a really good setup now, Kiyo!
My trim tabs will be able to reach a similar level so I am confident that my model will plane nicely as well. And I always use cae wax as well after my paint job. I think it is a good protection for the paint.
I am happy that your conversion turned out nicely. The video is impressive. What does the woman’s voice in the background tell? Nothing about the model I suppose?!

Backerther · « **Reply #111 on:** December 14, 2024, 08:00:31 am »

Thank you for always your complimentary and friendly comment.

My wife is playing a multi-role woman at the boating site like a timekeeper, a camera woman and a director to get better video scenes..

I am so much interested in your gorgeous Shannon to sail magnificently and powerfully, but it is scheduled in next spring?!..due to winter season...

But it may be you yourself who are much more impatient of waiting for the next spring to come rather than I am, isn't it ....!!!!?????

Arno, have you checked the moor cooling sufficiently actually as to use the boat in the bathtub for a few minutes at a certain rev,.already ? My boat is not necessarily complete yet still now at continuous top speed for 3 minutes or more..which is one of my next test themes to solve... As you know well, brushless motors in general are so powerful with excessively high RPM required to cool intensively especially during high speed run.... Take care of this point again for a successful test run.

I lost 2 cheap motors in this experimental prototype boat already....

swiftdoc · « **Reply #112 on:** December 14, 2024, 11:41:58 am »

I thought that in the timeline of the video after about 3 minutes it was not your wife but someone else making announcements via loudspeaker in the distance

I am waiting for more Super X which is in customs clearance in Amsterdam at the moment. I need to fix the problem with the water ingress first. Then I will fix the deck and paint it. That cannot take place at the moment due to the weather. I need to open the door of my workshop when painting as I use acrylic 2 component paint with solvent. It now would get too cold inside the room for a good painting result. So I need the patience to wait. I have been working for years on the build so do not want to spoil it on the finishing straight

Cooling my motors with water will be impossible as I am using outrunners. So far I can only rely on the work of others having used Kehrer jet drives with that setup and did have no problems. The hull is quite big so there is quite an amount of air for cooling. Time will tell if it all works as planned. I agree that a bath tub test cannot simulate the real sail properly.

If I lived nearby you I would be able to finish everything soon, but with the ice and snow over here a need to be patient. Next project will be the SS Falcon kit from Ron Dean, something completely different.

Backerther · « **Reply #113 on:** December 14, 2024, 01:27:54 pm »

I have understood concretely how far you should already have gone in the building process.
I think you may not have to be so impatient for the first trial run as you need more time to finish it completely.

The announcement through the loudspeakers was warning the visitors of the park no to do dangerous things in the park.

How I envy you since you already have a next project, Arno !!!

while I'm too old to challenge such a large model.

If I should build such large models and leave them in storage, it will greatly and surely bother my wife about what she should do with them after left lonely by me..??!!

That's why I have been trying to play the RC models in these years already built in stock rather than building new and large models.
In addition, my house is narrow to keep many and large models.!!

Backerther · « **Reply #114 on:** December 15, 2024, 02:53:30 am »

For a better and easy maintenance, I set a pair of nipples for blowing the water off left in the cooling tubes after finishing a day sailing. Unless doing that work, inside of the metallic tubes and ESC is apt to be rusted and/or stained with some sort of sediment
in a long time period by which a good flow of water will be largely disturbed, from my long experience....

Blowing the water off the line of cooling tubes is my routine job to do at home each time after cleaning the hull.

Backerther · « **Reply #115 on:** December 16, 2024, 01:33:06 am »

Let me show you just so short a video clip about my 109JP behaviour on the water, that was carried out as one of trial runs.
A water jet boat is found to be easily able to turn at minimum radius, not to say like Schneider propeller..!!

So much for today.!!

https://www.youtube.com/watch?v=2QA-svVBf9I

Backerther · « **Reply #116 on:** December 17, 2024, 08:46:17 am »

I enjoyed boating itself very much yesterday and took impressive pics about the wakes, splash and wave rather than the boat itself to which I would like you to mainly pay attention this time caused on a calm water surface.

Backerther · « **Reply #117 on:** December 22, 2024, 07:09:06 am »

Today I would like you to see very unusual pics of so miserable result of 109Jp taken place the other day on the boating lake.

Yes, a lead wire was completely burned off on the water and the boat suddenly stopped generating smoke from the hull
for a while...

Another one was burned just out at only insulation covering of the wire...

I used and operated the motor sufficiently within the specifications of Chinese manufacturer...
This was very first experience to have the motor blown off actually...a wire was broken off under the use of specifications.!!!!!

On the other hand, I still use another Chinese-made motors which are OK currently.

swiftdoc · « **Reply #118 on:** December 22, 2024, 08:40:06 am »

What a pity, Kiyo

So you had to use your inflatable boat again?! Did the motor draw too much current so that the diameter of the lead was insufficient?

My supply of Super X has arrived and I have applied it around the water jet drives. I will do another bath tub test after Christmas and hope there will be no water ingress anymore.
Keep up your good work, Kiyo. I know you must be upset after another setback

In the end both of us will succeed! Ultimately you might change the motor brand….

Backerther · « **Reply #119 on:** December 22, 2024, 10:35:45 am »

Yes, your imagination is perhaps true and too much current might have been drawn.

New brand of motors have showed a good impression so far in the intensive bathtub tests spending more time with severer conditions. KV4000 of old motors might have been too high with 2S lipo while new ones are 3200KV with 3S lipo under testing now repeatedly while increasing loads.

I also have been annoyed by the water ingress in the bathtub test reaching around 7 times or more as to add more Super-X
in each time...

Thanks to a sudden stop of my PT109JP?, I could have a chance to enjoy an unusual REAL(not RC) boating for myself.!!!

This was the very nice boating for me actually.!!!???

Anyhow, an improvement has been continuing still now to get a better, stable and reliable lake-going RC boat.

swiftdoc · « **Reply #120 on:** December 22, 2024, 10:43:18 am »

At least you kept on smiling

The new specification of motor/LiPo might be more suitable, I hope.

Backerther · « **Reply #121 on:** December 22, 2024, 10:59:13 am »

Yes, KV3200 was the smallest value among 3 alternatives suitable for the size of coupling hole...
With this specifications, less current draw is expected theoretically... and actually I have felt such an impression already in the
bathtub tests.

Final test of the year on the lake will show the result which is to be held around the Christmas day.

News:

Author Topic: 1/32 MTB PT-109 experimental project for this autumn (Read 9713 times)