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Old Dec 04, 2012, 11:32 PM
Foam air frame tester
Australia, QLD, Gold Coast
Joined Nov 2012
326 Posts
I found a Zlinger 20x10x4 for $62. It's wood with replaceable blades but its getting in the ball park on price.

On a separate subject did anyone's fuselage halves come not glued together properly? i have to find some big rubber bands so i can glue it back together properly
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Old Dec 05, 2012, 12:01 AM
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I am not concerned about the stock prop handling the rpm's at all. That think is so stout, I have hit it on the ground on take off and on landing (on asphalt), and belly landed in the dirt. All that abuse & I've only ground off less than a millimeter. Did not even need to re-balance it.

From my flight results, I just don't think this big stock prop is at all efficient at higher rpm's. I mean, at 90 amps, mine had to be spinning faster than the stock motor with the same battery, but it didn't seem any faster in the air. And I know it was pulling massive amps when unloaded in the air, because my low volt alarm set at 3.6 V/cell was going off on initial climb out, and it usually does not sound until that same battery is 2/3 depleted and at full throttle.

I would love to try this APC 15.5x12x4 blade. Not nearly as cool as the stocker, but painted black with yellow tips, I think it would look pretty nice and probably fly way better than the stock prop.
http://www3.towerhobbies.com/cgi-bin...?&I=LX1642&P=7

Jackson, I'll be very interested to hear how your 15.5x12x3 works for you when it arrives.

And d3, that big motor you found at HK looks like a great deal. 90 Amp rated & $42. They even have it in the USA and Australia warehouses. If my motor breaks, I'll get that one. http://www.hobbyking.com/hobbyking/s...arehouse_.html
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Old Dec 05, 2012, 12:11 AM
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I don't know if they (Starmax, FMS) make much effort in detailed design of the props, but often they don't perform linearly better if you just throw more power/RPM at them. Which suggests they DO somewhat match the prop to motor/RPM.
Throwing more power at them you usually you get much better 'torque' - ability to climb - seeing the prop is still operating well at the lower speeds, but in less loaded flight the benefit in speed terms diminishes (it then cavitates I guess).
So you really need a more suited prop that can truly deliver more thrust - whether from RPM or pitch.
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Old Dec 05, 2012, 12:26 AM
Foam air frame tester
Australia, QLD, Gold Coast
Joined Nov 2012
326 Posts
Hey PeterVRC, that's really what was in the back of my mind when i was writing my post. I guess at the end of the day you really cant make up for just having the right parts to build the right setup and the way to do this is run a prop with more pitch.

A 15.5" prop will look even more undersized than the standard one - maybe that's not a big deal for you guys? If you look at a pic of a real P-47 you will see what i mean, it runs an absolutely whopping 13 foot prop!

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Old Dec 05, 2012, 01:19 AM
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Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
820 Posts
The Quest for Performance

D3,

The APC 15.5x12x4 prop is the biggest four blade prop that APC offers. They have three others but all smaller in diameter. This prop is only $18 from Tower Hobbies. If it works, I consider that a bargain. It will not have the scale appearance of the stock prop, but you could always display the plane with the stock prop on, then drop the APC for actual flying.

I agree with you that it would be nifty to get to scale size, which should be easy to do with a two blade prop. However, consider that the incidence of prop strikes on landing will naturally go way up. What I am primarily after is something that offers good performance but still is vaguely "scale".

As an aside, I have an FMS Mustang 1400 mm V.6 that I have been experimenting with motor/prop combinations on. I am currently running an Exceed Rocket "4120" which is a 50-65, with a Kv of 660. I use a 15x10 two blade prop and power it with either 5 amp 4S or 5S batteries. On 4S this plane flies beautifully, on 5S she's a rocket ship. So far, the performance of the P-47 by comparison has been underwhelming. FYI, here is a video of the Mustang flying with 5S that I shot last weekend. The video is shot from the plane, but you can definitely tell that the plane is hauling ass.

Cheers, Jackson

Dogfight at Crosswinds 12-01-12 (5 min 3 sec)
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Old Dec 05, 2012, 01:39 AM
Foam air frame tester
Australia, QLD, Gold Coast
Joined Nov 2012
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It's really interesting watching your aileron movement in that video. It looks like it hardly moves down it all but has quite a large deflection upwards. Do you run differential on your ailerons?

I guess prop strikes arent a great thing on landing but if you are off the power, how bad are they for it and from the doccumentaries i've watched i saw quite a few upsidedown on the run way lol. Does that make it more scale to fly too

$18 is a good price and with your priorities definitely sounds like a good option. I would love to stay 4S too so i can just buy pairs of 2200mAh batteries which are more useful than one big one. What kind of amps does your P-51 draw?
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Old Dec 05, 2012, 09:24 AM
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Joined May 2008
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I moved to a 16x12 2 blade (http://www.hobbyking.com/hobbyking/s...propeller.html) a few weeks ago and don't plan to go back to the stock prop any time soon... I will be interested to hear the MAS 4 blade results.

The JM prop is hard resin type (like the stock) and very strong / well build.

Quote:
Originally Posted by Toppers View Post
I tried the HK JM 16x12 2 blade prop yesterday and loved it...

With stock motor and 4s batteries it was faster, and batteries lasted a lot longer.... normal full flight times (6-7 mins) was using < 50% of the 5000mAh battery (2765mAh remaining on my Quanum telemetry... which is also great). The speed is now very pleasing... a much better range and I'm no longer contemplating new motors or more cells.Thrust was still great... verticals, inverted and takeoff were just the same. There was also far less (no noticable) torque steer / veering left on takeoffs.... and it is 1/3 lighter (100g vs 155g stock)
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Old Dec 05, 2012, 12:06 PM
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Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
820 Posts
D3,

To be honest I don't remember the amp draw for the Mustang, but it is north of 60. I just burned out an ESC in the Mustang yesterday flying the 5S battery (another belly landing). Will replace it soon and test the whole system again with 4S and 5S. Jeez that plane is fun on 5S.

Jackson
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Old Dec 05, 2012, 08:34 PM
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Quote:
Originally Posted by Toppers View Post
I moved to a 16x12 2 blade (http://www.hobbyking.com/hobbyking/s...propeller.html) a few weeks ago and don't plan to go back to the stock prop any time soon... I will be interested to hear the MAS 4 blade results.

The JM prop is hard resin type (like the stock) and very strong / well build.
That JM prop looks tougher and a little more scale than the APC Thin Electric I just started using. I have one on the way from HK with my tachometer order.

FYI: If anyone in USA want to try that JM 16x12 2 blade, Toysonics has them. Shipping in USA is $3.96 for one of these, or $4.96 for two. Everything is 10% off there now when you add to cart. I've had good luck ordering props from them.

ToySonics.com also has the 15.5x12x4 APC four blade for less than Tower Hobbies, 10% off when putting it in cart.
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Old Dec 05, 2012, 09:12 PM
Feeling the THRALL
Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
820 Posts
Wow, that is great news on Toysonics. I have never shopped there but you can bet I will be now. I do like the selection and service that Tower has but you can be sure you will always pay full retail there.

I am about to check the video rushes of the day on the P-47. Hope to have a video posted to Vimeo later this evening.

Cheers,

Jackson
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Old Dec 06, 2012, 01:09 AM
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Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
820 Posts
Thunderbolt at Cherry Creek

Guys,

Here's a video from sequences taken at lunch today. The winds were strong and my videographer inexperienced, so it is not nearly as good as I had hoped for. But it has some nice sequences, especially the initial motor start sequence.

Was flying today on the stock prop and 4S and 5S 5 amp batteries. Plane handled well despite the winds.

I flew again at dusk. The winds had calmed and the light was fantastic. Sorry no video, but I will try again soon. During my flying at dusk I made a whole series of touch-n-goes. Man, did the P-47 handle nicely. I bring it in with enough power to maintain a good glide slope, then ease off the power and rotate for a nice flare and touchdown.

Best regards,

Jackson

Thunderbolt at Cherry Creek 12 05 12 (3 min 17 sec)
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Old Dec 06, 2012, 07:55 AM
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Nice video Jackson. That start-up IS cool! Do you have that programmed on a switch or does it do that if you just go real slowly up from zero throttle?
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Old Dec 06, 2012, 12:43 PM
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Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
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Quote:
Originally Posted by CrashMaster39 View Post
Nice video Jackson. That start-up IS cool! Do you have that programmed on a switch or does it do that if you just go real slowly up from zero throttle?
Crashmaster,

The Mr. RC Sound Module has a standard servo plug. You can set it up on a Y connector with the throttle lead if you want. In my case I mixed the throttle through another channel so I could have more control over when the sound starts and stops. The module is set up with three sounds: an initial start up sequence that lasts a couple of seconds, a main engine sound that is proportional to throttle, and an engine shut-down sequence.

Regards,

Jackson
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Old Dec 06, 2012, 12:59 PM
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Canada, ON, Oakville
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Great video.... looks like a beautiful day's flying.

Thanks for sharing.
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Old Dec 06, 2012, 03:12 PM
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United States, MA, Sterling
Joined Sep 2009
405 Posts
I have one (two actually) of the APC 15.5x12x4 props and will try it next time I can get out to fly. I don't have the stock Motor any more I have a motrolfly, and will compare it to the original prop performance.


Motrolfly Brushless Motor 3625-430

This 3625-430 motor comes with the special hub and was designed for the 1600mm Starmax War Bird Planes using the stock 4 blade prop. This motor is meant for sport and scale flying only. Motor comes with 4mm connectors pre soldered to the motor and matching female connectors will be included in the motor box along with all other mounting hardware. Max Amps: 80 Expect 60 to 70 amps on 4s with the stock prop and 75 to 90 on 5s. 5s with the stock prop you will need throttle management. Do not run the motor at full throttle on the ground as it needs good cooling. In the air on 5s 15 second full throttle runs should be done on straight away runs followed by a good 30 second cool down period at 3/4 throttle or less.

Some modification needs to be made to mount it to the firewall as the holes do not line up.
Motrolfly Brushless Motor 3625-430

Item #: DM3625-430

* Marked fields are required.
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Price $109.95
Availability In-Stock
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