Help Converting to Direct Drive
 

I have an old MRC Wellcraft Excalibur 40 Hawk boat and yesterday I stripped the gear in my gear reduction box and parts are near impossible to find. So I am forced to convert it to direct drive. Does anybody have any parts they recommend while still keeping it sub-surface drive.
Here is a picture of it, I have since put in an esc, a 17 turn motor, and motor water cooler.
http://i7.photobucket.com/albums/y26...4/PICT0872.jpg

RE: Help Converting to Direct Drive
 

Cool!.....................i have the same boat, i bought it on e-bay three months ago. My reduction still works on mine, and i've converted mine to brushless, a castle 4600kv and a sidewinder esc..............it flys!:D Take the motor out, and take the reduction apart if you can, see which gear is bad and try to find a "standard type" replacement for any rc, truck, car, whatever. If not you can put a motor mount in it with some modification (some dremel cutting i would imagine) and simply put the drive cup onto the motor shaft. This may take some modding too, the drive cup may be 4mm or 1/8 etc........... . I thought of doing this at first, but since my reduction still worked great i went with my present setup. Its a real sleeper...............looks like an old, outdated boat.......until i hit the throttle and it jumps out of the water.:D. Let me know if i can be of any further help, i'm interested to see what you do to fix it.

P.S. - i had to manufacture my own dog bone drive to handle the power, that little red plastic one is pretty thin.

RE: Help Converting to Direct Drive
 

Thanks, the gear that broke is almost part of the shaft it rides on to it is not really possible to replace. I am only running a 17t Reedy Radon motor in it. I tried just putting the drive cup on the motor but the cup hole is too big. Right now, my idea is to take a couple from an Aquacraft Hammer and bore out one side to fit my driveshaft. My only problem after that would be finding a smaller prop. Have you been able to find props that fit? I also just bought another one of these boats on ebay that I am going to rob the gearbox from and put it in mine, then I will modify the one I just bought.

RE: Help Converting to Direct Drive
 

Hi I have a BSA boat that must have been made at the same place as yours. The gear boxes are weak and easy to break. A Master airscrew gearbox will easily fit . The 2.5 to 1 ratio is perfect. They are fairly cheap too. Either the output shaft has to be reduced or the plastic drive cup slightly drilled out and you are ready. As a added benifit you get ball bearings.
n.h.schmidt

RE: Help Converting to Direct Drive
 

Hi
I'm back. You can order direct from Master Airscrew. The part no is MA3025G 2.5:1 . Its $22.95
Maybe could be had for less if you looked around. This will drop in and is much better than what you had.
n.h.schmidt

RE: Help Converting to Direct Drive
 

You can get props from Hobby Lobby Rc store...............i bought the 35 and 40's with 4mm thread. They are real cheap. You should consider making a hot rod out of yours too, you could put a graupner 700 in it and run it on 14.4 volts!!??:D

RE: Help Converting to Direct Drive
 

I looked at my LHS and they had no props that fit. I also just ordered a Master Airscrew gearbox from tower. I am currently running a 540 size 17 turn motor with 7.2/8.4v and my esc can only handle up to 8.4v and 15t. I may swap in a stock 550 motor if there is room. I also use this boat in a 13 mile long lake so it is rough most of the time. Do any of you have pictures of your boats?

RE: Help Converting to Direct Drive
 

i would replace that coupler. any more power looks like it will snap .



Ben

RE: Help Converting to Direct Drive
 

A 550 motor would be much better, you can get a graupner 600 8.4v. Its late here, i'll post some pics tomorrow.

RE: Help Converting to Direct Drive
 

Hi again
The new gear box will have a 3/16" output shaft under the aluminum prop hub. You will need to drill or file the drive cup to 3/16". If your prop shaft is like mine ,it's 4mm dia (5/32") and about 8 in long. Offshore Electric sells a Cen boat part cen-BJ14 prop shaft($8.99) that will easily fit your boat. It's a little too long but is easy to cut off to the legnth you need . The prop end is threaded 4mm so any 4mm threaded hub prop can be used. Offshore also sells a good selection of Graupner carbon fiber 4mm threaded props that would work great on your boat. Its the K series props you would want.
The prop shft also comes with a drive dog and 4mm to 3/16" adapter to allow the use of 3/16" hubed props too.
The advice is good about using a longer motor (550) like the 600 graupner motor. Even with the gear box you have a pretty good sized boat to move. You can save a bunch of weight using 2s lipos instead of a standard battery pack too. The idea is "to go faster add less weight".
All of this come from a lot of hair pulling a long time ago when I was new to rc boats.
n.h.schmidt

RE: Help Converting to Direct Drive
 

Thanks, I measured the prop shaft I have and it is 4mm and just like yours. Eventually I will upgrade it. I am also going to attempt to weld a dogbone out of thin threaded rod or similar stuff, its just going to be really hard getting the ground on it. Do you have any pictures of your boat? Also check this out basically my boat direct drive and brushless http://www.youtube.com/watch?v=XdDWehzKdwI
Edit- I am looking at getting a LiPo battery pack for this, it will be a 2s but what C would any of you recommend is 20c good enough.

RE: Help Converting to Direct Drive
 

can u get more pics of the whole boat

RE: Help Converting to Direct Drive
 

http://i7.photobucket.com/albums/y26...4/P8040766.jpg
http://i7.photobucket.com/albums/y26...4/P8040767.jpg
http://i7.photobucket.com/albums/y26...4/P8040768.jpg
http://i7.photobucket.com/albums/y26...4/P8040769.jpg
http://i7.photobucket.com/albums/y26...4/P8040771.jpg

RE: Help Converting to Direct Drive
 

Bordin, i've been out of town and promise i will post pics of my brushless version when i get back friday.......................in the meantime have you decided on a motor system? If you are going direct drive 7 cell, i pretty sure this motor will work:

if it comes up in German , click on the British flag - http://shop.graupner.de/webuerp/servlet/AI?ARTN=6310

or this one on direct: http://shop.graupner.de/webuerp/servlet/AI?ARTN=3302

Lemme know what you're thinking!!

P.S. - i just noticed your front air scoops are covered up, or are they just painted black and i cant tell in the pic?

RE: Help Converting to Direct Drive
 

I covered them up because they allowed water in if I jumped a wake and nose dived. I have sunk this boat completely at least five times and that helps it sink much slower. I am going with a 2.5:1 gear reduction instead of the standard 3:1 on this boat, however, the one I just bought on ebay will be direct drive. Right now I am going to be running a 17t 540 motor, a stock 550, or an E-maxx 550 on 6 and 7 cells. I also plan on buying at least one 2s lipo. All I want though is to be faster than a Tower Hobbies Turbo Vee.

RE: Help Converting to Direct Drive
 

I put in the Master Airscrew gearbox and it fits good and should perform better than stock. I will be testing it out tomorrow. My "new" boat should be here around Friday.

RE: Help Converting to Direct Drive
 

Hey Bordin......................sorry for the loooooong delay. I have been busy with so many projects, home stuff and family. I ran my boat again and it finally stripped out too. I went for a complete mod, no reduction drive. I had to do some cutting mods and found a way to install a Graupner 700BB 8.4v with my own homemade mounts (aluminum "L" stock, i use it for alot of things) I used a coupler off of a Cen boat and went with an Octura 630 prop. Im running it on 4s lipo (14.8v) with a Traxxas (Novak) 14.4v ESC and Novak smartstop LVC. My other rudder broke so i found this one somewhere and put it on. I just got back from running it.........runs great, motor temps about 110F . It will "jump" out of the water from a full throttle start and plane nicely, i havent checked the exact speed yet, but its more than fast enough for the little 25 year old boat. :D I would estimate 25-28 mph, and it handles really good, i mainly did this for my seven year old................something that can be ran up onto the bank and i wont really care. If you have any questions regarding my mods let me know and i wont take a month to get back this time.;)

RE: Help Converting to Direct Drive
 

Thanks, looks like I may have a winter project.

RE: Help Converting to Direct Drive
 

Did you ever hook up your reduction unit.............did it work? By the way, your boat looks to be in a little better shape, im missing some decals and a few chrome pieces. My windshields all had to be reglued too. Once again, sorry for my long delay...........besides my family and job and yard and band etc......... i have seven boats, three in modding process. Lemme know what you did to yours.;)