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Author Topic: Graupner atlantic challenger (times two!)  (Read 7240 times)

TomHugill

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Graupner atlantic challenger (times two!)
« on: April 01, 2014, 05:23:50 pm »

So a few weeks ago I picked up a pair of graupner azimut Atlantic challengers on eBay, one was in fairly original condition with twin speed 700 brushed motors. The other was supplied with the jet unit but nothing else (it was originally running a zenoh 26cc gas engine). Just to make things more interesting yesterday I picked up a 46" hull for a Virgin Atlantic challenger 2 (which was apparently used in the development of the real boat).  I've yet to take delivery of this but plan is to build this one up into a model of the VAC2 in a similar scale to the other pair.
 The first job is sorting out the stock challenger, the mechanical elements have been assembled really nicely. Unfortunately the detail and super structure could be done better ( the fella that built it seemed to like using silicon sealer as filler :S ) So I'm going to strip here back and rebuilt the super structure, add lighting repaint her and add stickers.
Below decks I've decided to go brushless and well be running two 2400kv 3674 inrunners on the turnigy marine 125a ESC's. These will run through the exciting geardowns and should give a 5000W+ power output. More than enough to give a good turn of speed where required.
Pictures to follow
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TomHugill

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Re: Graupner atlantic challenger (time two!)
« Reply #1 on: April 01, 2014, 05:25:06 pm »

As promised, the two AAC's as I bought them:

The nearest used to be petrol powered hence the holes in the stern

On the water:


Tearing it up

My mrs least favourite picture:

I'll get some of the build progress soon!
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TomHugill

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Re: Graupner atlantic challenger (time two!)
« Reply #2 on: April 01, 2014, 05:26:02 pm »

And here's the VAC2 hull


Being held by mr Branson

The real thing:
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TomHugill

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Re: Graupner atlantic challenger (time two!)
« Reply #3 on: April 01, 2014, 05:26:41 pm »

Some of the progress so far, been working on the rollover structure:



Repairing the railings and rear structure:


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TomHugill

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Re: Graupner atlantic challenger (time two!)
« Reply #4 on: April 01, 2014, 05:27:19 pm »

Excuse the conversation ith a passer by and the quality. Some reason it's not got on with YouTubes compression. I'm don't think she's going flat out in the video and it shot whilst the boat was running on a brushless system. I can wait for the brushless set to arrive from hobby king! 
http://www.youtube.com/watch?v=Fp-G1skE7Gw&feature=youtube_gdata_player
Ill be honest I have been looking for a nice woody for a while, but after a bad experience with a Vietnam conversion I bought on eBay I've been struggling to find something. I only got these because they where do cheap (159 for the pair on eBay!!).
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TomHugill

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Re: Graupner atlantic challenger (time two!)
« Reply #5 on: April 01, 2014, 05:27:52 pm »

A little update, finally got the lighting all plugged in. Port, starboard, front, rear and a flashing masthead (not really accurate but looks cooler!).


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TomHugill

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Re: Graupner atlantic challenger (time two!)
« Reply #6 on: April 01, 2014, 05:28:13 pm »

A little update, the brushless conversion begins! I've decided to roll with a pair of turnigy xk3674 2200kv motors. I'm still waiting for the water jackets to arrive but I've test fitted the motors. The stock speed 700s have a 30mm screw spacing and the turnigys have 25mm so some slight modifications where required but I've got them fitted nice and solid!


Hopefully the watercooling jackets arrive soon! I saw a similar brushless conversion on YouTube with same size and speed motors and it shifted!!
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TomHugill

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Re: Graupner atlantic challenger (time two!)
« Reply #7 on: April 01, 2014, 05:29:29 pm »

I got my water cooling jackets today, unfortunately despite being described as 60mm long mine where only 45mm still better than nothing I thought just so I could run a short test. Other work that had to completed was chamfering the drive shaft at both ends as the as with the increased power the grub screws holding the impeller on cant hack it!
Heres the setup as is:



First lesson from testing, the water pickups aren't working very well, even at a good speed I'm not getting much out the back. Im using 4mm ID piping, I think I could probably get away with 5mm would this make much difference?
Second lesson from testing, catastrophic failure of the belt drive is bad

The steel cable the reinforces the belts must have got exposed and then tangled around the pinion, destroying the belt and then cutting the pinion in tow.
So now I have to procure some replacements!
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TomHugill

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Re: Graupner atlantic challenger (time two!)
« Reply #8 on: April 01, 2014, 05:35:56 pm »

Well my initial drive thoughts where the drive belts where old and couldnt take the stress so I replaced them with new one. 5 minutes later and another shreded belt and busted pinion. So I decided to take the plunge and convert her to direct drive.
To necessitate this I cut away part of the bulkhead and added new motor mounts. I spoke to my LHS about this and they said they had done this conversion on afew challengers, they supplied universal motor mounts and universal couplings.
I was initially incredialous about using these couplings but I have decided to give it a go:




I've bench tested her which required me to remount the right hand motor as there was some issue with overheating and vibration. I've added collars on the shafts (salvaged from the damaged pinions) as the bearings were popping out and this prevents the drive shafts from moving.
I've not had a chance to get her in the water yet but im hoping that on the lake some of the vibration will be damped (I cant get my Najade past half throttle on the bench without it shaking the coupler to pieces but it runs fine on the lake). 
The right hand bearing seems to be heating up quite a lot, I've checked the alignment and its pretty spot on. Im  hoping its an issue with the bearing and a new one will solve this.
I've ordered some flexiable heavy duty rubber couplings in case the U-joints fail. Also hoping these will cut down the vibrations.
Finally I've decided to swap out the motors to lower KV. Currently I have some 2200kv 3675s in to achive 15-20k RPM on 4s. Now I've not got the gear reductions the jet drives are pushing 36-40K rpm unloaded. This is far too much and will endanger the jet drives. Im dropping down to some 1100kv 3674s 1500w each. I should have the same top speed I did before which is plenty!
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Stavros

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Re: Graupner atlantic challenger (time two!)
« Reply #9 on: April 01, 2014, 08:22:13 pm »

WOAH big time.........you need to realign those motors to get them 100% IN line if you dont those couplings WILL EXPLODE trust me on this been there had the tee shirt....Those couplings are only rated to around 8k ....Now the trick to get around this is simple......get the motors and shafts in PERFECT ALIGNMENT then simple wrap insulation tape around them...both my Lesro javalin and cygnus revenge both rev to 21000 rpm and are ok like the way I have said...NO TAPE = blown coupling
 
 
Dave
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TomHugill

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Re: Graupner atlantic challenger (time two!)
« Reply #10 on: April 01, 2014, 08:31:24 pm »

Hey Dave, that's annoying :/ I was supplied the mounts and couplings with assurances they would be fine. The mounts are angled so I guess ill need new mounts! Oh well. Thanks for the advice though I'm sure I can use the parts on another project!
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TomHugill

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Re: Graupner atlantic challenger (times two!)
« Reply #11 on: April 02, 2014, 12:02:20 am »

New mounts ordered and have some power flex couplings coming too. Just need to work out how to remove my current mounting blocks!
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TomHugill

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Re: Graupner atlantic challenger (times two!)
« Reply #12 on: April 14, 2014, 10:56:17 pm »

Some more progress tonight, got one of the motors mounted. Seems to be a lot less vibration, alignments a lot better. Hopefully the power flex couplers will hold up.



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TomHugill

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Re: Graupner atlantic challenger (times two!)
« Reply #13 on: April 18, 2014, 11:07:39 am »

Well both motors remounted with power flex couplings from Steve at Modelboat bits. Bench tested and all seems ok, vibration isn't excessive even at full throttle.

Now I have a quandary, when I did the brushless conversion the boat still had the 2:1 geardowns and I bought the 2100kv motors to match this. So when I took them away I ordered some 1100kv motors (with a higher power ratig). Now I'm not sure if the 1100s will be too slow or I should sill to the 2100s. Some testing will be required! I'm wary I don't want to cook the motors or destroy the jet drives.



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gregk9

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Re: Graupner atlantic challenger (times two!)
« Reply #14 on: April 18, 2014, 01:37:53 pm »

You may well be ok with the motors you have put in, as you have to be careful to to over rev the jet drives and just cause cavitation in the drives themselves, moving you no where.

At least with the 1100's in you can simply experiment with battery voltage to get the rpm right, so start with 2 cell, then try 3 or if still not enough, 4 cell.

If you put the larger motors in, if it over revved at 2 cell, you're stuck with few options.
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TomHugill

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Re: Graupner atlantic challenger (times two!)
« Reply #15 on: April 18, 2014, 04:03:50 pm »

Hey, I'm currently running on 4s so my thoughts where a an 1100kv without gearing should be the same speed as the 2100s with gearing. We shall see!
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TomHugill

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Re: Graupner atlantic challenger (times two!)
« Reply #16 on: June 08, 2014, 09:20:12 am »

Well it's been a long time but she's almost finished, a lot has been done since the last update. The universal couplers had to go, I used heavy duty rubber ones instead. I've remounted the motors, bought some 1100kv motors which work much better. The cosmetic reconstruction is almost complete too as I managed to track down the decal set.

Some pictures:

I'm not a great one for tarting up interiors, if they work that'll do me!







And the outside, still needs finishing touched like reprinting the reversing buckets, some more antenna and a new mast head bit:






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TomHugill

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Re: Graupner atlantic challenger (times two!)
« Reply #17 on: June 08, 2014, 02:22:31 pm »

http://youtu.be/uxwBmg0tmsU
Quick video of her up at Bury!
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pompebled

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Re: Graupner atlantic challenger (times two!)
« Reply #18 on: June 08, 2014, 06:21:20 pm »

Hi Tom,

You must be very popular with your fellow boaters...

The boat runs very nice, judging by the sound of it, a bit more weight wouldn't hurt to keep the jet intakes flooded at full throttle.

Regards, Jan.
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TomHugill

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Re: Graupner atlantic challenger (times two!)
« Reply #19 on: June 08, 2014, 06:46:42 pm »

I've not hit anyone yet!! I try and give people a wide bearth though when I'm hooning it! To be fair she's very manuoverable and predictable (unlike my najade!) I see what you mean about the extra weight; I didn't notice it when she was running but she does seem to jump out a few times.  I just need to finish he and get all the stickers sealed with some tough satin varnish!

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andra

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Re: Graupner atlantic challenger (times two!)
« Reply #20 on: June 08, 2014, 06:50:08 pm »

SUPERB boat and restoration Tom, looks like she goes and handles like a dream. :-))

Andy
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Martin [Admin]

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Re: Graupner atlantic challenger (times two!)
« Reply #21 on: June 08, 2014, 07:46:29 pm »


 Great scale looking speed!
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TomHugill

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Re: Graupner atlantic challenger (times two!)
« Reply #22 on: June 10, 2014, 09:54:15 am »

The end is nigh! Just a few bits and bobs to tidy before I seal her with satin (or gloss) laquer. Least nights job was to rebuilt the mast and associated lighting. I used 4mm thin walled aluminium tube with the lamps and platform bits off the original graupner part. I used surface mounted LEDs for abit more punch.









Next job is to paint it matching white and add all the antennas!
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andra

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Re: Graupner atlantic challenger (times two!)
« Reply #23 on: June 10, 2014, 09:25:44 pm »

Looking fab already Tom, bright even in daytime, will look stunning in the falling light!

Andy
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derekwarner

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Re: Graupner atlantic challenger (times two!)
« Reply #24 on: June 10, 2014, 10:51:35 pm »

 :((   perish the thought of sealing those surfaces Tom.......... "before I seal her with satin (or gloss) laquer"

1. I understand you need to protect the externals
2. How do you prep surfaces that have waterslide transfers already installed?
3. Will lacquer adhere or just turn yellow & peel?

I would be inclined to talk with our resident Mr Paint guru  [ :} Dave aka STAVROS]  first O0 ......Derek
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