Corona Langeweile - oder die Performancesteigerung einer Micro Maritimo

[J Mack]

Herzlichen Glückwunsch Patrick 138-136 km/h ist mit Micro Cat erstaunlich.
Ich habe Ihre Fortschritte mit großem Interesse studiert, vielen Dank für das Update. Ich werde bald mit dem Bau von zwei Micro Driftern beginnen und freue mich über alle Informationen, die Sie geteilt haben.
Wenn Sie Zeit haben, würde ich mich über aktuelle Bilder Ihres Micro Maritimo freuen, die ich in meine Sammlung aufnehmen kann.


Grüße,
Jim

[Shark]

Hello Jim,

hier some pictures of the current stage of the mini cat ...

Best regards,
Patrick

[J Mack]

Patrick, ich glaube, Sie haben eine ausgezeichnete Herangehensweise an Ihren Build, indem Sie eine Änderung vornehmen, alles validieren und dann zur nächsten Änderung übergehen.
Nachdem Sie nun viele Theorien zu diesem Rumpf getestet haben, werden Sie mir sagen, wie Sie einen brandneuen Rumpf einrichten würden, wenn Sie von vorne beginnen müssten?
Ich lese alle Ihre Kommentare und schaue mir alle Ihre Bilder noch einmal an, um einen guten Ausgangspunkt für meinen Micro Drifter-Rumpf zu finden.
Vielen Dank für Ihre Zeit,
Jim

[Shark]

Hello Jim,

although this is a German forum it is ok if you write in English if you like to. I'm comfortable with both ...

Last year I build also a Micro Drifter in almost the same way as the Micro Maritio. The motor mount is bigger for motors with 36mm in diameter. The performance is also the same as the one of the Maritimo. Attached some pictures ...

If I have time and don't forget it I will make a video next time when I drive the boats.

If you have any questions feel free to ask ...

Best regards,
Patrick

[J Mack]

Patrick,
I appreciate you taking the time to share the details of your builds with me and I have many questions but I will try to keep them to a minimum and not clutter up your build thread here.

On the last photo you posted of your Micro Drifter you have extended your tunnel similar to your Micro Maritimo. I was looking at a build here in the USA and they were having areo lift issues and their solution was to build a diffuser to raise the rear of the tunnel. Do you believe this would have any benefit on the smaller hulls? I will try to post some pictures for you to see what I am talking about.
Your work on the runners is very interesting on the Drifter, would you give some more detail on the dimensions, I would like to duplicate what you have done to one of my hulls here.
Regards,
Jim
Difuser_3.jpgDifuser_4.jpgDifuser_5.jpg

[J Mack]

Patrick,
I scaled your photos the best I could and started on the bottom of the hull, I assumed the carbon strips you used are 15mm. Do you think this will work?

Thank you,
Jim
a6.jpg

[Shark]

Patrick,
I appreciate you taking the time to share the details of your builds with me and I have many questions but I will try to keep them to a minimum and not clutter up your build thread here.

On the last photo you posted of your Micro Drifter you have extended your tunnel similar to your Micro Maritimo. I was looking at a build here in the USA and they were having areo lift issues and their solution was to build a diffuser to raise the rear of the tunnel. Do you believe this would have any benefit on the smaller hulls? I will try to post some pictures for you to see what I am talking about.
Your work on the runners is very interesting on the Drifter, would you give some more detail on the dimensions, I would like to duplicate what you have done to one of my hulls here.
Regards,
Jim

Hello Jim,
sorry for responding late ...

Discussions which are not "Off-Topic" are always welcome.

Aerodynamic feature work more or less on both, big and small hulls. If you have lift issues the question has to be answered, if it is to much lift or if the center of pressure is on the wrong location. When this is done, adequate solutions have to be found to get rid of it.
In my opinion and the way I understand the way the tunnel should work on tunnel hulls, the worst idea is to build a tunnel or a part of it like a diffusor. Diffusors are used at race cars to produce down force so that they can handle higher speeds during cornering. And I don’t know if this should be the same aim here. Because of the downforce the boat will have a higher frictional drag and will consume a lot of power.

But it would be nice to see how a tunnel boat works with such a diffusor and if the experience with it could be shared here.

Regards,
Patrick

[Shark]

Patrick,
I scaled your photos the best I could and started on the bottom of the hull, I assumed the carbon strips you used are 15mm. Do you think this will work?

Thank you,
Jim

The steps in the front have a height of 3mm on my Micro Drifter and yes, you are correct with the width of the carbon strips of 15mm. The height of them is 2mm.
Apart from the diffusor like tunnel ending it should work. But as I said before, it would be interesting to see how it performs as you have built it. Let me / us know …

[Shark]

Da das diesjährige SAW immer näher rückt wurde es Zeit die Micro Maritimo mal wieder zu Wasser zu lassen um zu sehen ob das neue Servo und die restlichen Sachen noch wie gewohnt ihren Dienst verrichten. Die kleine Ausfahrt habe ich mal endlich in zwei kurzen Videos festgehalten. Am Anfang war ich noch etwas zögerlich, da ich den Cat schon fast ein Jahr nicht mehr gefahren bin und es war auch nur ein kleiner Prop drauf. Trotzdem standen 122km/h auf der Telemetrieanzeige ...

[J Mack]

Thank you Patrick I will continue with the rear diffuser and report back as soon as I get on the water.

For your information this is all the information I can find on the boat here in the US with the rear diffuser.
https://m.facebook.com/OttoRCMarine/...48&__tn__=EH-R

I don't know if you can open this page but it says, “the addition of diffuser tunnels have now been proven to increase downforce sufficient to offset areo lift at high speeds enough so that 3 ° degrees of drive down trim have been removed from the hull which allowed one size larger propeller to be run at the same RPM and 20 less amps. ”

[MiSt]

As far as I know, diffusors are preferred over spoilers on race cars, because they produce downforce without excessive aerodynamic drag (limiting the top speed on straights) like spoilers do.

Drawback of diffusor-made downforce is that it collapses suddenly (!) as soon as the distance to ground exceeds a critical value. This led to a couple of catastrophic race accidents in the past, for example Audi airborn in LeMans in ???? - I do not remember the year, a quick search in www revealed it happened several times. EDIT: And thanks for the video below, this was more exactly the accident I had in mind, but it was a Mercedes this time ... /EDIT. Le Mans is mostly a regular road, so it is much more risky to rely on a constant distance to floor (as it is optimistic to do so on water ...).

On race boats, I once have read about a diffusor-like structure just in front of the COG of roundnose-hydroplanes. They planned to downforce exactly the COG to compensate for the extensive area in front of the COG, which is typical for roundnose designs. At the time I was interested in this (I was building a '65 "Miss San Diego", and planned to equip it with such a thing), I did not find so much about this, unfortunately. So it stayed incomplete, as so many boats in my home :-(

[MoD]

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[J Mack]

Patrick I see the photos but cant find the results, can you share how you did here please.

A6404133.jpgA6404148.jpg

[IlCapitanoAlex]

https://www.rc-rennboote.de/forum/sh...ight=m%FCnchen