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Old Jun 04, 2009, 04:52 PM
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Hey Tam, whats the maximum recommended air pressure for your retracts?
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Old Jun 04, 2009, 04:58 PM
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That looks good techspy... I'm to scared to put it in the side of the fuse
but you did a great job.. you could always add a little fan like mine just for the heck of it

I think you'll be fine with the airflow you have now... just keep it on low timing
the funny thing about all this airflow is , I contacted chris wolf at JHH and they run the CC110 in there A-7 on 12s with no airflow at all and have no issues... but I guess it's just the luck of the draw and more airflow is always a good thing..

Ron
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Old Jun 04, 2009, 05:15 PM
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San Jose, CA
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Quote:
Originally Posted by techspy
Hey Tam, whats the maximum recommended air pressure for your retracts?

100-120 psi.
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Old Jun 04, 2009, 05:50 PM
The blade numbers go up to 11
stumax's Avatar
Sydney, Australia
Joined Aug 2002
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Quote:
Originally Posted by Neil Guildford
The performance of the DS 75 in terms of speed is faster, but I prefer the effortless sound of the Stumax. The sound of the TJ100 is also not my preference. I'm running 11S 3700 (a 6 and 5) Rhinos at 2.7kw.
You can run 12S but in my opinion this requires larger cells to keep the flight time up. I fly for 4 mins on the timer and down on the ground in about 5, which generally uses 2500mah.
Hope this helps
Neil
I'm not so sure, Neil. The data I have is that for the same in flight power, there's very little difference between the two. The key is measuring the in flight power, as the SM110-52 unloads 10-15% in flight, whereas the DS75 doesn't. A Spark with a 2.7kW SM110-52 setup will unload to about 2.4kW in flight. A 2.4kW DS75 powered Spark will have about the same top speed, however, the takeoff and low speed performance is less.

If all you want is all out speed, then of course, a smaller diameter fan (of the same efficiency) will be best. If I was putting together a Spark with about 2.5-3kW and just wanted to go fast I'd go for a DS51, as the small exhaust diameter it allows will have much more dynamic thrust than any fan which is larger. The down side is that the takeoff performance won't be great, and it may not even get off a grass strip.

Stu.
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Old Jun 04, 2009, 06:06 PM
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Quote:
Originally Posted by stumax
I'm not so sure, Neil. The data I have is that for the same in flight power, there's very little difference between the two. The key is measuring the in flight power, as the SM110-52 unloads 10-15% in flight, whereas the DS75 doesn't. A Spark with a 2.7kW SM110-52 setup will unload to about 2.4kW in flight. A 2.4kW DS75 powered Spark will have about the same top speed, however, the takeoff and low speed performance is less.

If all you want is all out speed, then of course, a smaller diameter fan (of the same efficiency) will be best. If I was putting together a Spark with about 2.5-3kW and just wanted to go fast I'd go for a DS51, as the small exhaust diameter it allows will have much more dynamic thrust than any fan which is larger. The down side is that the takeoff performance won't be great, and it may not even get off a grass strip.

Stu.

Stu,
Not fan war....read my post earlier.
I think let Spark thread going clean is benefit everyone don't you thinks is better.
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Old Jun 04, 2009, 06:29 PM
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Quote:
Originally Posted by JimDrew
I wonder if we all fly at the same time at top speed if that will cause a ripple in time and help speed up the BVM planes that are behind us?
So you guys are hitting 200 MPH with the Spark?

Jack
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Old Jun 04, 2009, 06:34 PM
The blade numbers go up to 11
stumax's Avatar
Sydney, Australia
Joined Aug 2002
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Quote:
Originally Posted by Tamjets
Stu,
Not fan war....read my post earlier.
I think let Spark thread going clean is benefit everyone don't you thinks is better.
Tam, I'm not interested in starting a fan war, I have better things to do, I was just clearing up a misconception that the SM110-52 isn't fast. It's not designed for all out speed, but can hold its own amongst others.

Stu.
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Old Jun 04, 2009, 06:57 PM
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Ok, I just ran a couple throttle-ups to get some numbers.

Hyperion 12s 4200mah G3 lipos

Run 1
Pack Low Voltage 42.39 volts
High Amps 120
High Watts 5181

Run 2
Pack Low Voltage 42.03 volts
High Amps 119.99
High Watts 5115

The first run was only at wot for approx 10sec with no warm up. Run 2 was for approx 10sec wot after approx 1 minute in between the first run with the motor running at approx 10% throttle. So run 1 was with cold batteries and run 2 with warm.

Do these numbers look good?
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Old Jun 04, 2009, 07:12 PM
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Quote:
Originally Posted by jfetter
So you guys are hitting 200 MPH with the Spark?

Jack

Hitting 200mph is great. But can it do it long enough to kept up with the Spark doing 170.
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Old Jun 04, 2009, 07:18 PM
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Quote:
Pack Low Voltage 42.39 volts
High Amps 120
High Watts 5181
Dude... that can't be right
Are those 30c packs? My DS-94 with a 1521 on 12s can only hit 4700 watts burst with a steady 4400 watts..

maybe it hits that high for a second then drops off?
but still those are huge numbers and will smoke the ESC

Stu would know better than me.. but that doesn't sound right too me
if they are that high you will have a guided missle

Ron
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Old Jun 04, 2009, 07:22 PM
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They are rated as 35c. They are supposed to be some bad ass batteries.

http://www.rcdude.com/servlet/the-13...X--dsh-/Detail

Yeah I know thats going to be pushing it with my cc 110hv. Might have to look at a bigger esc.
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Old Jun 04, 2009, 07:28 PM
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Oh 35c!!
Dear god... maybe that is right...
that thing is going to be insane!!
Wow.. I didn't think the Stu Max could hit that kind of power
That's cool

I was only hitting 85 amps and blew my ESC.... I think you'd need a power jazz or the new CC140

Ron
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Old Jun 04, 2009, 07:28 PM
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Miramar, Florida
Joined Jul 2007
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Quote:
Originally Posted by Ron101
Dude... that can't be right

Ron
Looks right to me, that's not even that high compared to the Thunder Power Pro Power 40C packs. His cells are holding a little above 3.6 volts, we're seeing 4.05 volts when doing 10 second run ups with the TP's...

Jack
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Old Jun 04, 2009, 07:31 PM
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Here are the graphs. It looks like they are bursting to 5k+ then settling down to 49k or so
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Old Jun 04, 2009, 07:33 PM
The blade numbers go up to 11
stumax's Avatar
Sydney, Australia
Joined Aug 2002
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Quote:
Originally Posted by techspy
Ok, I just ran a couple throttle-ups to get some numbers.

Hyperion 12s 4200mah G3 lipos

Run 1
Pack Low Voltage 42.39 volts
High Amps 120
High Watts 5181

Run 2
Pack Low Voltage 42.03 volts
High Amps 119.99
High Watts 5115

The first run was only at wot for approx 10sec with no warm up. Run 2 was for approx 10sec wot after approx 1 minute in between the first run with the motor running at approx 10% throttle. So run 1 was with cold batteries and run 2 with warm.

Do these numbers look good?

Wow, those cells are giving good voltage. I hit similar power levels with 12S XPS 5000's. Use that much power with great caution! The motor can handle 4.2kW continuous, a bit more in bursts. You may actually be better off with 11S, which will drop the power to below 4kW, but also be lighter. If you stay with 12S then limit throttle ATV to keep the power under control.

Stu.
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