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Author Topic: Is there a better MkII Springer?  (Read 4548 times)

chrise

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Is there a better MkII Springer?
« on: June 07, 2009, 10:41:35 AM »

In another thread Toesupwa wrote:
The Springer shape is the reason it 'dives'. Yes, because it is an inverted wing shape.. plus the snow plow effect of the flat front doesnt help matters.
I've done several experiments with inverted 'winglets' under both the stern an the bow trying to stop the dive... and nothing seems to work. The only success i had was with a small wing underneath the bow, but even that only held off the inevitable dive... it went under at higher throttle.

I have not built a Springer but am going to do so. Whilst I understand the reasons for a common shape etc I was wondering whether there was a MkII Springer out there that would combine all the advantages of the MkI - ease of build, strength, price, easy handling size, cuteness, flexibility etc with better sailing characteristics that would extend the flexibility of the original hull design. It may of course be that the original is the optimum shape.

Has anybody tried any, or any combination of, the following & can thus report on what happened:
1. Making the bow narrower than the stern
2. Making the hull deeper at the bow ie increase the bow buoyancy & reduce the underwater airfoil shape.
3. Increasing the "lift" angle at the front of the hull so that increased speed tends to lift the hull more.
4. Adding a slight amount to the hull length & if so in which bit of the hull shape.
5. Making sure the propshaft is horizontal with the water line
6. Anything else!!!

As some of the above are the exact opposites of each other you can tell that I am not sure which, or combination of which, would improve matters & which would make them worse. If anybody knows please tell me.

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FullLeatherJacket

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Re: Is there a better MkII Springer?
« Reply #1 on: June 07, 2009, 11:15:02 AM »

How about mounting the battery on rollers and linking a servo to the ESC via a Y-lead to move the battery backwards as the forward speed increases?  %)

FLJ (aka Heath Robinson)
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chrise

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Re: Is there a better MkII Springer?
« Reply #2 on: June 07, 2009, 06:09:54 PM »

Somehow gets away from the simplicity bit.   :}
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FullLeatherJacket

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Re: Is there a better MkII Springer?
« Reply #3 on: June 07, 2009, 06:26:36 PM »

Somehow gets away from the simplicity bit.   :}

Yeah - but if a job's worth doing then surely it's worth over-doing?  8)

"Just a bit of fun, officer........."

FLJ

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Bill D203

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Re: Is there a better MkII Springer?
« Reply #4 on: June 07, 2009, 09:46:52 PM »

I have just about got over mine diving. I fitted a tube around the prop so it pulls the back down and the front up. It dose not cure it all but it is a very big help.
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toesupwa

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Re: Is there a better MkII Springer?
« Reply #5 on: June 08, 2009, 06:17:14 AM »


Has anybody tried any, or any combination of, the following & can thus report on what happened:
1. Making the bow narrower than the stern
2. Making the hull deeper at the bow ie increase the bow buoyancy & reduce the underwater airfoil shape.
3. Increasing the "lift" angle at the front of the hull so that increased speed tends to lift the hull more.
4. Adding a slight amount to the hull length & if so in which bit of the hull shape.
5. Making sure the propshaft is horizontal with the water line
6. Anything else!!!


1/ If you alter the shape of a Springer, its not a Springer
2/ If you alter the shape of a Springer, its not a Springer
3/ If you alter the shape of a Springer, its not a Springer
4/ If you alter the shape of a Springer, its not a Springer
5/ Yes...
6/ why?

Start with an 18" x 8" Springer 'box'... and you have a Springer, If you deviate from the Springer box, you dont have a Springer, but something totally diferent..

Like i said... Just take it easy with the throttle...
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nick_75au

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Re: Is there a better MkII Springer?
« Reply #6 on: June 08, 2009, 06:44:23 AM »

I  don't understand the air foil theory ? and why/how it applies to Springer hulls
A foil requires the flow to split, passing over and under the foil, this dose not happen as one surface is interacting with water and one is interacting with air. so no lift/down force can possibly be generated. I think what happens it the second wave after the bow wave is lining up near the stern, its this rising water that is lifting the stern , also the trough after the bow wave is right on the deepest part of the hull, I think this is why the bow loses buoyancy.
In answer to 6
move the weight aft. I put my batteries behind the motor, at rest they sit a little stern down but once moving they level off nicely
Nick
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chrise

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Re: Is there a better MkII Springer?
« Reply #7 on: June 09, 2009, 10:41:53 AM »

I have just about got over mine diving. I fitted a tube around the prop so it pulls the back down and the front up. It dose not cure it all but it is a very big help.

Do you mean like a fixed nozzle?

Mick75_Au
I don't understand the airfoil bit either but it is a frequent comment here. I prefer your idea that the wave form creates a hole that the model falls into.

Toesupwa
I know what you are saying but if there is a better way that looses nothing then it is worth knowing about

Everybody
Has anybody other than Bill D203 experimented? If so did your experiment work?

Chris
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portside II

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Re: Is there a better MkII Springer?
« Reply #8 on: June 09, 2009, 01:21:53 PM »

Easy , hang a trailer on the back . I did , and at full chat the bow is kept up as the trailer drags the stern down  :} .
I have tried it without the trailer and it does dive :(( , oh and its still a springer .
daz
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toesupwa

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Re: Is there a better MkII Springer?
« Reply #9 on: June 09, 2009, 04:29:24 PM »


Has anybody other than Bill D203 experimented? If so did your experiment work?


Have a look at this discussion..
http://www.rcgroups.com/forums/showthread.php?t=705061

Yes, i have tried a few things... and to a degree, it did work.. But overall, the hull still dives..

http://www.rcgroups.com/forums/attachment.php?attachmentid=1370686
http://www.rcgroups.com/forums/attachment.php?attachmentid=1375306
http://www.rcgroups.com/forums/attachment.php?attachmentid=1391025

The only other way, is to go 'with' the diving...
http://www.rcgroups.com/forums/attachment.php?attachmentid=1717463  :D
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chrise

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Re: Is there a better MkII Springer?
« Reply #10 on: June 10, 2009, 11:39:55 AM »

Thanks for the links. Hours of reading!

It does sound like the basic problem is overdriving the hull shape.

Chris
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