DF 29 7XL to go fast -timing and prop q´s

[FastVee]

Ok, so I finally got it running, here are the videos .

timing 1 deg.



timing 7 deg.


Temps never went above 55deg.celcius.(mostly about 40), but bateries were quite warm, about 50 I think.


The 7 deg. timing looks a bit faster, but what to do next? -I want to use this 7xl, I have better ones(like 2200 Castle /Neu), but This is just build to see how fast will it go with 7Xl and 4S.

More timing? -the next step on the esc is 15deg... -too much?

I have few props ordered, like x442 and m440, I allready have s215,s220,x440,x637,x642,x645,m445.

The s220 is way slower then s215,so the prop size should stay about x442,right?

I know it runs a bit wet, will raise the strut angle b4 next outing.

any suggestions are welcome!

The esc is Himodel 200A 3-7 with external bec.
Motor Feigao 7XL
Batteries Turnigy 30/40C hardcases.
All connections are made using Castle 6.5mm bullets.


-Pate

[Brushless01]

Try it on auto-timing if the esc has it.

[785boats]

I run my 7, 8, & 9 Xl motors on 15 degrees with the Himodel GX 200A 3- 8s ESCs
They seem to run cooler. So one would assume that they are running more efficiently & therefore delivering slightly more power to the prop.
I might do some tests with an aircraft prop & a power meter on one of them & see which timing setting pulls the least amount of current. That should tell us which setting is the best. Maybe? I'll prop it to be pulling around 80-100 Amps initialy.
Cheers.
Paul.

[FastVee]

Ok,cool! Thanks Paul. I´ll try it at 15 deg.timing next, and will mod the props a bit more. It is high 40´s boat now(46mph at 1deg. timing and S215 prop,no gps of the 7 deg. test), hoping to get it close to 60 mph.

what boat do you have that 7xl in? -and any favorite prop for it?

Do tell if you test the amp draw later on. (usually more timing,more amps,but also more rpm´s)

-Pate

[785boats]

I've got the 7Xl in my old Apparition 32"cat on 4s with an X437/3 blade at the moment.

Well I did a little test but I don't know how much use it is
I set up a 9Xl (cheap Chinese one) with a 10 x 7 electric prop on 4s with a Himodel 200aESC
On one degree timing it pulled 141A & the voltage slumped from 16.7V to 13.33V.
Too much prop I thought so the rest of the tests were on an 8" X 4" prop'

1 degree ....139.67A 16.43v to 14.88 Vm.
7 degree.....139.84A 16.43V to 14.91 Vm
15 degree...140.00A 16.38V to 14.82 Vm.

So then to give the 15 degree timing setting a more equal shot, I topped up the battery & did it again. Took on 460mah.

15 degree...140.46 16.80V to 15.04 Vm.

On each test I only ran it at full throttle for about 3 seconds.
But I didn't think that it would draw so much current on a little 8" x 4" prop.


I'll leave you guys to draw any conclusions. I know it's a completely different scenario between air & water but I thought the differences between the timing settings would be more pronounce. Oh well. It was all good fun.
Cheers.
Paul.

[Brushless55]

That sucker is moving!
I wonder if a 6XL would be to much?

[FastVee]

Thanks 785 boats, I just tested 15 deg timing and it was not that hot, 45 esc and motor.(celcius)

The speed was a bit better thought ...65.5mph. (105.55kph) -x440



Got 6s to try next.

[Brushless55]

That's killer!

[785boats]

Well done.
I only got mine to around 50mph, in oval running trim, on the 7Xl. What's your secret?
Cheers.
Paul.

[FastVee]

The secret is in the SV hardware

I really dont know, today I got it to go only 57mph on same setup, only different batts(low C rating). the 2s packs that were used on the fast run have lost their punch, but I have 3s packs ready to smoke! -or go, just want it to move.

will start on 5s and x440 and until it smokes or flies will try up to 6s and up to m445

what ever happens ,it will be taped.

So in few days well know more...


-Pate

[785boats]

A 7Xl on 6s with a 445 prop will definitely ignite. That's miles too much.
I wouldn't do that if I were you.

[FastVee]

A 7Xl on 6s with a 445 prop will definitely ignite. That's miles too much.
I wouldn't do that if I were you.

See the danger. THEN DO IT ANYWAY!!!

I dont want smoke on the water,but if it happens, new stuff can be bought with money.

but seriously, I´ll try the x440 0n 5s, then s215 on 5s, and if that is not enough, will try the same on 6s.

The motor should handle short runs, it has 70.000rpm bocas inside.

If I use the larger props, I will change the motor too to 1515 1y that i have all ready.



-Pate