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Old Nov 18, 2012, 02:09 PM
bryansifsof44's Avatar
United States, AK, Anchorage
Joined Oct 2011
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For that prop on 8s the website recommends a wind of 282kv to 2700 watts... 3000 watts is pushing the motor I think. I just got the ok from Ken for my cooler climate to run the motor to 3000. But with Extreme flight's recommended 2600-3000 watt electric setup for the 78 extra I wouldn't doubt it's capability of pulling the plane nicely. 3500 watts is crazy power for this plane... but should be similar to the 3000 watts I'm putting in a 70 class 3Der. BTW, how big is the ground clearance with the 22" prop... I'm thinking the 22" on this size would have the ideal effect the 14" and the 16" props have done to the 48" EXP and 60" EXPs. However, with the 4330 I am looking forward to real world reports and will post some numbers once I get some results from testing.
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Old Nov 18, 2012, 05:57 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
7,249 Posts
Quote:
Originally Posted by bryansifsof44 View Post
I'm thinking the 22" on this size would have the ideal effect the 14" and the 16" props have done to the 48" EXP and 60" EXPs. However, with the 4330 I am looking forward to real world reports and will post some numbers once I get some results from testing.
Exactly right. All are between 27% to 29% of the wingspan. Same as the 20 inch on the 70 EXP. If you didn't see the video I took of Tom flying Frankjp's 78 at the Deland Huckfest, check it out and let me know if it's not dancing around the field like the 60 on the 16... and the 22 clears by just over 4 inches with all three wheels on the ground.

Tom Kitt Flies the 78 inch Extreme Flight Extra 300 (5 min 21 sec)
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Old Nov 18, 2012, 06:24 PM
Facts, Logic, 3D
Tom K.'s Avatar
Florida
Joined Nov 2010
3,585 Posts
My dad (Aeroplayin) told me I should come on here and give my two cents on the different props we've tried on Frankjp's 78" Extra with the Hacker/Castle 10S setup.

When I first started flying Frank's Extra, he had the 21x10 Xoar on it. This prop was good as it wasn't too amp hungry, pulled out of a hover, and gave me the power I needed for most maneuvers to look decent. However, it wasn't all too great. Nothing special. I knew the motor was capable of a 22x10, so when I was asked about the prop I said something along the lines of, "If we couldn't put a 22x10 on it, it would be fine. But we can..." The reason why I didn't especially like the prop was it was slow. At full throttle the plane didn't look like it was in any hurry to get anywhere on the straight and level, and when I went vertical out of a high speed pass, it still took it's time getting to altitude. I don't think I flew above 200ft even when setting up for spins and stuff with this prop because it just took so long to get up there and I got sick of waiting and nosed over.

So we put the 22x10 Xoar on it. With the 22" prop it pulled slightly more amps, but my flight time was still 6 minutes and it all came down at 3.7-3.75 volts per cell, which is right where I like them. The 22" prop made all the difference! It picked up a few mph on the straightaway and it made it look like it was flying fast. It pulled out of a hover with much more authority and oomph behind it, and I really liked it. The throttle pulses during my rollerz and other maneuvers were more pronounced, and therefore allowed me to be more precise. I really like the prop, and it was much better than the 21".

Like I said before, the 21" was just slow. It had power out of the post-stall stuff, but that was it. The top end... sucked. The vertical climb out speed sucked. It was adequate, but not what I'm used to on my other planes (granted, my other planes are stupid with power:weight). So the 22" prop was much better. It flew fast going straight, had thrust out the whazoo post-stall, the bigger cone of air helped in post-stall flight, and I liked it a lot.

Finally, yesterday we had the 22x10 Mejzlik Carbon Fiber electric prop in the car when we went to the field to give Frank his plane back (he lent it to me for the Huckfest. Thanks again Frank!), and we did some testing with the Carbon prop. It was about 15% heavier than the Xoar, and at the same diameter and pitch it produced a few more amps (literally, 4 or 5 amps). I only had time for one flight with this prop as the sun was going down and we were all hungry for some BBQ. So I grabbed a flight and... I like this prop even better than the Xoar of the same diameter and pitch. The Xoar had power, the Mejzlik had slightly more oomph and instantaneous power as there's probably less flex in the Carbon prop than the wood prop. Also, I noticed it produced a bit more torque in a hover, and made my torque rolls without aileron more consistant. However, since there was more instant power with the Carbon prop, I could still pulse the throttle and stop the torque roll if I wanted to with the application of opposite aileron.

So, in closing, my 78" Extra when it's done (just waiting on a 3.5" pull-pull arm for the rudder), will have that slick Carbon Fiber Mejzlik Electric 22x10 prop on the front end with the same Hacker setup. I'm hoping it'll be done by next weekend.

This is just my opinion and what I found when I flew with the different props.

--Tom K.
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Old Nov 18, 2012, 07:54 PM
Shut up and Fly!!!
jw357_23043's Avatar
United States, VA, Hartfield
Joined Aug 2011
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Has anyone here ran a Torque 2818 900kv on any of their 48" EXP's?
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Old Nov 18, 2012, 09:28 PM
bryansifsof44's Avatar
United States, AK, Anchorage
Joined Oct 2011
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Quote:
Originally Posted by Aeroplayin View Post
Exactly right. All are between 27% to 29% of the wingspan. Same as the 20 inch on the 70 EXP. If you didn't see the video I took of Tom flying Frankjp's 78 at the Deland Huckfest, check it out and let me know if it's not dancing around the field like the 60 on the 16... and the 22 clears by just over 4 inches with all three wheels on the ground.

http://www.youtube.com/watch?v=M4Ul6...rRhN2SFIXhlqQw
I did see that... very nice flying.
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Old Nov 19, 2012, 09:37 PM
VOLTS > AMPS
stgdz's Avatar
United States, MN, Buffalo
Joined Jul 2011
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Anyone seen these sk3's?
http://www.hobbyking.com/hobbyking/s...dproduct=18167

kinda tempting but it is a turnigy........



Also castle is having a firesale this week on some esc's
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Old Nov 19, 2012, 11:12 PM
Shut up and Fly!!!
jw357_23043's Avatar
United States, VA, Hartfield
Joined Aug 2011
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Quote:
Originally Posted by stgdz View Post
Anyone seen these sk3's?
http://www.hobbyking.com/hobbyking/s...dproduct=18167

kinda tempting but it is a turnigy........
I had the SK5065-380 on my 70" EXP and it was nice. I replaced the bearings and rewound it down to a 320kv. I finally retired it when I got a Motrofly due to not having the time fix it after a vital nose dive on another air frame. I ruined the bearings and need to replace them.
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Old Nov 19, 2012, 11:40 PM
can't buy vaporware
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United States, MN, Minneapolis
Joined Nov 2011
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I had a Turnigy SK3 3548 700 kv. Great motor unless you do KE spins, even with just light throttle. The housing broke near a bearing after less than 10 flights...was too thin for 3D.

Not sure about those larger 4240s
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Old Nov 20, 2012, 12:11 AM
Shut up and Fly!!!
jw357_23043's Avatar
United States, VA, Hartfield
Joined Aug 2011
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Check out this find:http://www.rc.futaba.co.jp/motor/index.html

I wonder what these can handle? Prices aren't too bad if you can translate!!
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Old Nov 20, 2012, 12:23 AM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
7,249 Posts
$244 for a 15.5 oz 300Kv motor?

Motrolfly's DM-4325 is $170. Seems like another opportunity to over paid for the Futaba name, but I'm not even curious about this.
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Old Nov 24, 2012, 01:32 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
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Okay, here's a thought. I now have about 30 gas, glow, and electric props I don't use anymore, and was looking through them this morning. I found some old 16x10 electric props that I never used because they were too light for the 1.10 motor, 8S setup that I had on a H9 Frenzy a few years ago. String that together with the fact that I was on the HPartz site thinking about more 6S batteries for the 60. I'm buying mostly 5S 40C 5000 batteries now because we have two planes with 10S set ups now, so I started thinking -- which is always a dangerous thing....

I went to the PropEngine and plugged in the numbers. I then went to the Subsonic website and saw a 17 inch prop on the 4315 with 6S on the 380Kv wind option. Hmmmmmm....

If the motor can handle the 17 inch prop at about 6900 to 7000 RPMs (380 wind times 22.8v times 80% KvE), then it should handle a 16x10 on the 480Kv with 5S to 7300 RPMs, no?

If so, then the 5S setup on the 480 will produce about 66A at WOT and just under 1300W and about 1430 on the 500Kv option, or the MKII. That's also 9.45 lbs of static thrust and almost 70 mph of pitch speed, and about 2 more minutes of relative flight time. To put things into perceptive, that's less Watts per pound at WOT but more pitch speed throughout the rest of the throttle curve. The trade-off is 1.92 oz or 54g, which may mean hoping that putting the 5S batts right up against the wing tube will give me the same CG. I also found a 17x8e APC.

Tests pending...
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Old Nov 24, 2012, 04:09 PM
They Call him Dead!
YellowJacketsRC's Avatar
United States, SC, Pawleys Island
Joined Jul 2003
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So what's the advantage here? You're still on a 16" prop and a 16 x10 likely is more suited to speed than it is 3d no?
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Old Nov 24, 2012, 07:01 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
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Well, there may not be any advantage other than sticking with 5S batteries for the duration. My thought is this:

[1] Same diameter means same static thrust and vectored thrust throughout the throttle cure right up to the point where the 6S speeds the prop up more on the same Kv.

[2] With two more inches of prop pitch, I'm generating more speed, and perhaps more kinetic pull because of it, than the 6S on and 8 pitch.

[3] Since I govern the Amps to 65A anyway, the only thing we may notice is the added speed on the 10-pitch prop. Don't know yet, but I think it should be noticeable.

If this all works out to be the case, then we may actually notice improved performance moving from the 6S to the 5S setup as long as I have enough room left to work out the CG correctly, and the extra 54g of weight goes unnoticed.

Considering the DM4315-500Kv and the MKII at 500Kv, the top end may be even more similar for guys that don't have Amp restrictions. The debate here is between static thrust measurements and the actual fish scale measurement of the 'pull'. At WOT, one setup will register more Watts per pound and more static thrust, but the other will provide the actual mechanical thrust needed to go faster.

Since it's the same disk size, the question for 3D flying on the Edge is really about how the pitch influences performance everywhere except the throttle range between 65A and 1235W and 65A and 1482W. Everything else in the throttle curve should be up for grabs.
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Old Nov 24, 2012, 07:13 PM
They Call him Dead!
YellowJacketsRC's Avatar
United States, SC, Pawleys Island
Joined Jul 2003
7,061 Posts
Ok so I do understand after all. The 5 s plane should go faster.

But I have always understood that there was something sort of magical about maintaining something close a 2 to 1 diameter to pitch ratio when it comes to 3 d flying. I thought it was because a shallow pitch has tin spin faster to produce same power and in slow 3d flight those extra RPMs were seen as advantage to stability?? ?
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Old Nov 24, 2012, 08:16 PM
VOLTS > AMPS
stgdz's Avatar
United States, MN, Buffalo
Joined Jul 2011
3,867 Posts
I like motrofly's

This doesn't count the two that are in my laser and mxs.
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