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Author Topic: XRAD'S HYDROPLANE  (Read 12795 times)

martno1fan

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Re: XRAD'S HYDROPLANE
« Reply #50 on: April 19, 2016, 11:45:22 AM »

I honestly think your props are way too large for that setup,the motor wont get to its peak rpm with such a large prop and cause things to overheat or worse.Personally id be looking at 67 mm prop for that setup ,check what others are using as ive not seen any using props that big on a FE setup.
Mart
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xrad

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Re: XRAD'S HYDROPLANE
« Reply #51 on: April 19, 2016, 12:53:32 PM »

Thx Martno.  Will give the smaller prop a shot!  I did try a 3 blade ~67 1.4, but it did not push the boat.  This 5698 motor is ~6 hp at 200 amps. The original 26cc gas engine maybe could be tuned to a  'max' 3hp. Should be enough power to turn the x678 or x478.


Right now I am at 8s, but the 5698 could run 10s, have to use a different esc.


Check out this video,  kind of gives ballpark specs:


https://www.youtube.com/watch?v=aSP2wLB7rFM
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martno1fan

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Re: XRAD'S HYDROPLANE
« Reply #52 on: April 19, 2016, 05:51:48 PM »

Thing is FE uses higher rpm than gas so smaller props are needed if using the higher rpm ,if you were going to use those bigger props youd need a lower kv motor and less  cells maybe only 6 . Gas boats rpm is around 16-19 k rpm which is ideal for 69-75 mm props,less rpm the bigger prop like a 280 would work,but for 25-35 k rpm you need smaller props. A friend is using one of the 5694 1000kv motors i have in a 70" mono on 8s and its very fast,hes using a 67 mm prop.You need a high lift prop for your hydro,my gas hydro ran 65+ mph using a 6717 /3 at around 18 k rpm ,motor was a full mod around 6.5 hp .I think you might be ok with that prop or a tad bigger like 69 -70 mm.
That video you linked if you notice hes using a cut down 70 mm prop cut down to 63 mm,so i think my suggestion of smaller seems to be the right way to go,not trying to tell you what to do but just what id try if it were me.
Another tip i was always told to do with a hydro is to always toss her in with some throttle to help them get up on plane easier.
Mart
https://www.youtube.com/watch?v=wVGBWC_3MuY
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xrad

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Re: XRAD'S HYDROPLANE
« Reply #53 on: April 19, 2016, 07:01:12 PM »

thx Martno. I just ordered a 470 SS for trial.  Will put that on with the new batteries and test it.


The number one issue seems to be getting more power to the motor.  The motor and esc were not even warm with my original set-up.
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martno1fan

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Re: XRAD'S HYDROPLANE
« Reply #54 on: April 19, 2016, 09:21:05 PM »

If the  lipos werent up to the job that could be the main issue so hopefully the larger c rating ones will give you that power you need then you can test all the props you have .My friends large mono using similar setup is fast but things are running pretty cool,just warm he told me  :-)) .I hope to get my Apache finished in the coming weeks but im in the middle of reorganizing my workshop,you wouldnt believe the crap ive thrown out lol.
Mart
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xrad

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Re: XRAD'S HYDROPLANE
« Reply #55 on: May 01, 2016, 09:45:29 PM »

Bought x4 5000 4s 100c  Venom water cooled packs.  max motor draw is about 200 amps. Max battery discharge rate is 500amps per 4s.  10,000mah total per x2 battery group. Should have about 4.5 min of good run time. I series wired 2 sets of 2 packs for the base voltage ~32v (~max for motor and esc).  Then parallel wired the series packs , maintaining voltage. I used Offshore Electrics (THANKS for fast shipping as always!) 6mm bullets for all battery connections (all with 10 ga castle braided wire) and final + and - wires to esc are 8 ga w/8mm bullets. I think the Deans and traxxas connectors have too small a contact area for this power level. BUT, I have to be careful to hook everything up correctly!

Hooked up and tested and ran fine.  Basically, I have more than enough deliverable battery power, and an esc that can maintain constant 200amp w/burst to 800amp, and a motor that draws max 200 amps (or a bit more...) So it should all be good now on the power side of things.  Received a few different sized props for testing including the ss470. I just have to polish and balance them....

As far as the batteries, I removed the Venom shrink wrap and removed (CAREFULLY) the three heavy brass plates and cooling tubes from each pack.  Probably about 2 lbs minimum in weight savings, not to mention the silicone tubes and all the water they would have held.  My motor draw is way less than the 500amp max battery output. Even hot and pushing timing and a big prop, motor draw should not exceed 250-300 amps.  I double wrapped the packs in 3 1/4" clear shrink wrap form Offshore Electrics. Now the packs all fit nicely into the front of the hydro.....

I also added a metal case/metal gear high torque servo and 1.5 inch aluminum servo arm (servo something like 13kg/cm at 6v).  The generic servo I had was under powered. (on ebay : Power HD LF-13MG Metal Gear Digital High Torque Servo 4.8-6.6V 1:10 RC ) works great with my Rx. NO chatter. Holds position perfectly.
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xrad

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Re: XRAD'S HYDROPLANE
« Reply #56 on: May 02, 2016, 12:05:09 AM »

By the way, venom 4s 100c 5000mah were cheapest I could find.......


Tower hobby insane price of 140$, amazon 107$,  or ebay for ~73$ (each)!!! 
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xrad

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Re: XRAD'S HYDROPLANE
« Reply #57 on: May 02, 2016, 03:28:16 AM »

Made another change: The ptfe tube was rotating (slow and fast) intermittently at about 20k rpm and above, and there was some lag in rpm after this. I cleaned and lubed the flex tube and tried to remove any lube from outside the ptfe tube. But it still turned...not fast, but the brass stuffing tube was warm...and this was for only a few second run. I did not want to glue it in place.

So out with the ptfe, and into the 11/32 stuffing tube went a length of 5/16 brass tube (actually had to be hammered in gently) This 5/16 brass liner protrudes about 5mm out of motor end of stuffing tube for ease of removal...(my stuffing tube sits inside another short length of stainless through hull tube so that the whole assembly removes easily) . It had to be gently heated (not the ends) to ease it through the bend, but it was still pretty hard. Don't want a soft tube as a bushing....there is a small gap of about .5mm or less, around the flex shaft, not too loose, not too tight. Ran VERY smoothly at top end, and no lag or bad vibrations.....and stuffing tube was cool after the run! But I did notice that the grease was working its way down the flex shaft and out the rear at the strut.....Archimedes screw pump in reverse...hopefully will keep out water! Will definitely have to be careful about lubing.

For the moment, seems like another issue solved.
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martno1fan

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Re: XRAD'S HYDROPLANE
« Reply #58 on: May 04, 2016, 04:41:54 PM »

Yea i always glue in the teflon liners or they do spin and heat up and can melt,once glued in they work well,i then use oil instead of grease but if using bare brass your best using grease to stop water coming in.Look forward to seeing some video of her running .My Apache builds on the back burner as i have a few orders for hulls to finish up,hopefully ill get her done before Summers over lol.
Mart
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xrad

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Re: XRAD'S HYDROPLANE
« Reply #59 on: May 08, 2016, 01:53:02 PM »

Made a vacuum forming device. Uses house and shop vac. Heated lexan sheet to ~200 F. worked pretty well for first attempt. Good thing because I only had one sheet!

Testors bright yellow matched pretty well.  Nylon cover screws...all very light and less wind resitance, and better splash protection than original scoop (which can still be placed on top without issue)

Some props to test 78,72,70 mm dia.....


hopefully get to the lake today...
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xrad

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Re: XRAD'S HYDROPLANE
« Reply #60 on: May 09, 2016, 12:11:38 AM »

Got out to the lake today. Perfect day, except for the crash!  Plenty of power, motor was really revving up nicely. I was not even at full throttle...maybe 3/4 plus and caught some wind and a wave and smashed her up pretty badly. I did make an adjustment to the strut angle to compensate for additional battery weight, but I suspect that this was not needed. Much prop wash noted before accelerating.....

Hull separated completely on starboard side and all the way across the transom.  But I can take away from this that I now have pretty close to what I want in terms of battery, esc, motor and prop combo. The rudder functioned well.

Fantastic video:
https://www.youtube.com/watch?v=s95poIWCJj8

Slow mo:
https://www.youtube.com/watch?v=HP8I_8-0Wrs
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derekwarner

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Re: XRAD'S HYDROPLANE
« Reply #61 on: May 09, 2016, 12:29:28 AM »

OUCH :o....even in slow motion the wave is neigh on impossible to see xrad........

Is the hull gluable/repairable of would the extra weight upset the balance?

You may need a mirrored lake surface to reach full potential........... but never fear 'sedate steam' craft will always be available

[Did you know that Donald Campbell's father [Sir Malcolm] was a steam buff as a youngster?] .......... Derek
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Derek Warner

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xrad

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Re: XRAD'S HYDROPLANE
« Reply #62 on: May 09, 2016, 12:40:14 AM »

Hi Derek!  All is repairable(will depend on interest)....I may just glass it on the outside...all the way around!  Even with letting off the throttle, there was still a bit of prop kick that caught the last wave and launched the rear, then the nose dive....

I would like to her dialed in, if not for the challenge...
And my GPS meter was on but not set to record...so I did not get a top speed  :((
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martno1fan

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Re: XRAD'S HYDROPLANE
« Reply #63 on: May 09, 2016, 12:25:42 PM »

Looks like the seam isn't glassed on the inside with 2 " cloth tape just glued  ? typical of how Aeromarine used to do their hulls some years ago,should be an easy fix .Tape her together outside and glass from inside using 2" cloth tape and epoxy resin,if you run some masking tape along the seam line outside any excess will seep through to the tape filling the void,clean off once dry and wet sand and repaint.
Im also finding it hard to find any waves though lol .
Good job on the vac formed cowl .
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xrad

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Re: XRAD'S HYDROPLANE
« Reply #64 on: May 09, 2016, 12:38:07 PM »

Thx Martno.  Yep, just glued. Hull too tight to reach into to glass from inside in most areas. easy to fix from outside. I knew this was a fragile hull when I bought her.....I may also lay up some CF on the inside where I can reach....
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xrad

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Re: XRAD'S HYDROPLANE
« Reply #65 on: May 09, 2016, 09:14:37 PM »

I think I hit my own wake!  :embarrassed:
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martno1fan

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Re: XRAD'S HYDROPLANE
« Reply #66 on: May 09, 2016, 10:06:35 PM »

Yea you would need to remove things from inside the hull to do the repairs from inside,youd be surprised how easy it is to get inside a hydro once the hull is empty.A small brush on the end of a stick works ok for the areas you cant reach. Most difficult thing is getting the cloth tape to go where you want it when you cant reach,im used to doing it by now but it is tricky.
Glassing it on the outside is easier as you say but then getting it to look nice wouldnt be so easy,maybe if you get a nice cloth or even carbon tape then epoxy that and once its set maybe go over it a cpl more coats to get a smooth surface it wouldnt look so bad as the carbon would look nice if glass you could just paint as normal.
I use this tape,im sure you can get this your side of the pond.

http://www.ecfibreglasssupplies.co.uk/p-1775-fibreglass-tape-200g-x-25mm.aspx


http://www.ecfibreglasssupplies.co.uk/p-512-25mm-carbon-fibre-plain-weave-tape-200g.aspx
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xrad

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Re: XRAD'S HYDROPLANE
« Reply #67 on: May 10, 2016, 01:42:06 PM »

Thx Martno, but there is no way to lay up glass on the inside where the damage is due to construction design. That is why it was glued.  The seam is at the deck margin which means that the glass/tape has to be laid 'inside right angle' which is prone to lift . You can't even see the area to know if you glassed the right spot or glassed it well.  That is why it was originally glued.  would have to cut off the deck, glass the sides, re-attach the deck.  Easy to glass from outside or just re-glue as originally done.
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xrad

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Re: XRAD'S HYDROPLANE
« Reply #68 on: May 14, 2016, 08:08:25 PM »

found some 3m scotchweld epoxy DP100. Mixes in the applicator. Will work nicely as initial inside glue.   
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derekwarner

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Re: XRAD'S HYDROPLANE
« Reply #69 on: May 15, 2016, 01:09:53 AM »

mmmmmmmmm 3M Scotch Weld 1838....one of the most expensive glues around  .... [USD$1,700.00 per gallon]

Widely used in Military applications.......[but worth every cent when lives depend on it :-))....]

Derek
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Derek Warner

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