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Post by John L on Apr 28, 2020 14:46:12 GMT
Hi all,
I have managed to purchase an unbuilt in the box ED Krak-a-long kit and I want to build it as a submerged drive fast electric. One of these owned by Frank Carr (I think??) was powered by an HP40 raced at Stevenage in the mid to late 1970s. I would like some advice on motor size/prop size please.
Thanks
John
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Post by Ian.S on May 2, 2020 14:31:35 GMT
Hi all, I have managed to purchase an unbuilt in the box ED Krak-a-long kit and I want to build it as a submerged drive fast electric. One of these owned by Frank Carr (I think??) was powered by an HP40 raced at Stevenage in the mid to late 1970s. I would like some advice on motor size/prop size please. Thanks John Hi John, Fast Electric’s not my greatest forte, but just wondering the size and type of the boat. I take it you’re thinking about a brushless setup ? |
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Post by John L on May 4, 2020 13:09:13 GMT
Hi Ian,
The Karakalong was originally designed for up to .30 cu in or 5cc glow motors . it's 28" long and 10.5" beam moderate vee. I still have an OS30 from about that era but I think I would prefer brushless.
Regards
John
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Post by John L on May 5, 2020 13:12:52 GMT
I mentioned what I was trying to do to a friend i used to fly with and he recommended a motor and battery combination that I actually have in my parts bin.
It's a Turing Aerodrive SK3 3542 1000kV. it would swing a12x8 aero prop on 4 cells at around 50A. According to some old charts I found that is equivalent to an X50 Graupner marine prop! I was looking at X45 or X445 for the Krakalong. So i think I will start with that setup, especially as it's already here.
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Post by trevorg on May 12, 2020 10:46:23 GMT
Hi John, The Krakalong was a fast steering boat from late 60's to early 70's. With the start of multi racing such hulls were used. As they were not deisgned for this purpose as power levels rose they would spin (a lot !!). The Krakalog was the most popular hull of its type and raced by the then Stevenage Club (SMAMS) with considerable success. The other issue was that like most hulls of that period they have a wood deck on a fibreglass hull. Any collision and the deck lifts. I have a 1972 catalogue showing both the Krakalong and the improved Krakalong S. The Krakalong kit sold for £8.75 although the hull could be purchased for £4.41. As an electric model it lacks a flood chamber but as this is a stable hull this should not prove a problem. I would try a 2850 or 2860 size brushless on a 3-S LiPo but the setup you mention would make a good start just to see how things go. For that size of hull An X45 or X40. Modern practice on submerged drive hulls is to use a higher reving motor and keep the prop size down but this is more of a classic.
I have attached a picture of my Tornado68 being chased by Jim Pallets Krakalong. Don't know the date but it is taken at Black Fan Lagoon before the club moved to Fairlands Valley so probablyabout 1970.
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Post by John L on May 13, 2020 22:10:49 GMT
Hi Trevor,
Thanks for the reply. The Krakalong has some weird and wonderful features for example the forward fuel tank, the offset rudder (3/16" ti the right of centre) and the rudder itself narrow at the top and wide at the bottom. The kit was complete with all hardware in the original box. In 1975 I ran an ED Nippy (the smaller version) with an Enya 19 and then a Veco 19 it too had the spinning trait particularly with the Veco in it.
It should stir up some nostalgia when it hits the water in the distant future.
The picture is brilliant! I went to the Lagoon a few times in those days.
Regards
John
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Post by simonm on May 14, 2020 18:39:48 GMT
Hi John, I am going to attempt to do an attachment, ah it seems to have worked!! I don't need to tell you what it is! My records show that this was in 1975.
Simon
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Post by John L on May 15, 2020 20:48:57 GMT
Simon,
That picture is superb!
I have fitted the prop shaft and rudder this week ready for fibre glassing. i will post pictures soon
regards
john
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