Build Log 36" Shelly Foss build..revisited

[more coffee]

Not on hand ...best i can get is an automotive one ..I have been looking for one that reads 0-20 or even 30 in 1-2amp increment or so ..but havent to be able to find one ..
Any suggestion?

[Kmot]

WattsUp Meter

http://www.rc-cars-planes.com/

AstroFlight Watt Meter

http://www.astroflight.com/index.php...=index&cPath=2

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Forgot to mention Tom..I had to resurect this one ..I re-ground a pair of brushes out of a Briggs & Stratton starter motor to fit this ... It's probably not top ..but for dimension ..it will work to get the idea how the gear will set ..I can get more..for about 22 bucks a pop..

I did note that when running properly ..they will run all day swinging a 6 inch fan and not pop a 5 amp fuse ..

Thanks for the links ..I do have to do something about the ammeter issue ..

The watts up ..i do like the data aspect ..

[Kmot]

I have a WattsUp and have used it extensively. It holds data until you disconnect the battery source. Just so you know.

[more coffee]

Originally Posted by Kmot

I have a WattsUp and have used it extensively. It holds data until you disconnect the battery source. Just so you know.

DOHHH !

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After alot of head scratching and tossing idea's around ..Im left with the Black Hole of Doom ...Ive cut mock props from box board and trial fitted the shaft's n tube's ..cant seem to get my head around it ..

How does one hold and align twin shaft arrangement's???

One or both at a time ?

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OK ..so I go to get the shafts in ..following the pictures and note's supplied by Dumas ..that was a mistake ..

the initial full scale drawing is for Kort installation ..a miniature figure shows the basic twin screw arrangement..
however in both drawings when installed on the hull ..allows no room for the rudder's..

The shafts have to be moved about 1/4 to 3/8 of an inch further forward..just to allow the rudder blocks to be drilled..
so instead of installing the strut immediately behind station 7 its has to be ahead of it ....
This kit has been a little bit of a pain ..when a guy doles out this much quid ..i would expect to get the brass parts required and not have to make other parts out of scrap plywood ..
Dint think I'll ever do another Dumas kit ..
OK I'm over it

[Kmot]

The good news is...............

It's early in the game so you can pull it out and relocate it and easily fill and patch the other holes and it will never be noticed.

[patmat2350]

Originally Posted by more coffee

How does one hold and align twin shaft arrangement's???

One or both at a time ?

My general process for one shaft, where I try to get perfect shaft and motor alignment, and then still use a double u-joint to minimize vibration:

1. Get everything roughly laid out, including the rudder.

2. Make a rigid coupling the same length as the planned u-joint assembly, with set screws to lock onto the shafts.

3. Contrive and whittle a motor mount that will be set into the hull; get this as close as possible.

4. With the shaft propped up in the right place at the hole in the hull, and motor rigidly locked to the shaft, set the motor mount into a bed of construction adhesive in the hull.

5. When that's set, fill in the hole in the hull around the prop shaft (wood blocking, fiberglass, epoxy, whatever).

6. Replace the rigid coupling with the u-joint, and enjoy the smooth running.

7. For twin shafts: Make fixtures to hold the shafts at the required distance from each other, at each end. Extra points if the fixture also has an alignment to the centerline, more points if the fixture establishes the right heights at both ends to avoid a corkscrew effect. Some jury-rigging can be expected!


p.s.: I also always make a support for the inner end of the shaft to keep it from whipping around. This is left loose until step 5 is done. It might be a hole in a bulkhead, like 1/2" for a 5/16" tube. But then I have a disk (or two semi-disks) with the snug 5/16" hole, and I glue or screw these around the shaft at the bulkhead to seal the deal.

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Thanks Pat,makes much more sense ..

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well the shafts are in..need a little tweaking on the rudder's to plumb and square ..not much though ..
I used round stock instead of the flat bar in the struts ..my luck i would have created two fixed rudder's ..there was no way i could get them straight on

where the struts pierced the hull I used 3/8 ply with an over sized hole ..5 minute epoxy and hopefully Bob's yer uncle ..helps stiffen them

I cut a block to set the height at each strut,Dumas drawing's call for approx 2 in here ..in the end it was a tad over 1 1/2 with the tubes moved further in the hull a extra half inch to clear the rudder's

overall after that they were pretty straight on ..good lay out before cutting helps ..not that mine is good but it helps situate the parts in the known cosmos..

Really have to quit putting of a cradle ..especially now the shafts are vulnerable
Not to mention finish the spots on the hull ..and begin the deck and superstructure..
hull below waterline i think well be flat or semigloss black ..

[more coffee]

The motor's I have selected ..the wire's are connected via the brush carrier ...



So to install caps ..I gotta do it inside the motor or can i splice and insulate them on the wire leads ??

..what Farad ..for a 12V system ,12 pole motor

[Kmot]

Question #1:

What radio frequency will you be using?

If the answer is 2.4ghz than you do not need caps.

Otherwise, yes you can just splice them into the motor leads. You will still need to solder one end of each cap to the motor can.

3 caps:

Pos wire, to motor can.

Neg wire, to motor can.

Pos wire to Neg wire.

[more coffee]

Ok thanks Tom ... I have some heat shrink floating around here ....somewhere ..

FM radio, HITEC ..havent been able to break the GHz barrier ...the boss wont allow it

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Forgot to mention ...This is the fan i used ...stripped down to get the motor ..They run for 40$ a pop ..and are available at most truck stops ,truck parts or automotive supplier's ..They are also available in 24V

Its a Signal two speed fan ..and they are imported by Docap outta Mississauga ,Ontario , Canada

Or if you happen to know somebody with a few bus's or trucks that are being used as donor vehicle's ...pay them a visit ..

The motor is in a can so it doesnt get much if any ventilation...but bullet proof
1/4 shaft ,12 pole, 12 volt .. lotsa- torque