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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Robert Redmon on January 29, 2012, 08:56:38 AM

Title: APC 11x5.5 changed as well
Post by: Robert Redmon on January 29, 2012, 08:56:38 AM

I have been using the original (now apparently unavailable) 11 x 5.5e thin hub/blade props from APC since last spring (when I first started flying electric). The motor is an Arrowind 2820/07, and the plane is a Brodak/Smith Vector .40 that weighs 48 oz with  battery. Motor run time is approx 5:30. Using the older "thin hub" props, Lap time was 5.3 seconds with the motor set at 9200 rpm. I had been using from 1350 to 1450 mah from the battery depending upon wind. Yesterday, I switched to a prop that I purchased a few weeks ago that has the thicker hub. Battery usage stayed about the same, but lap time dropped to almost 6 seconds. I repitched the prop to the same pitch I have been setting my "new" 12/6e props on another airplane, and the lap time is now 5.2...very close to what it was with the "thinner" version of the prop, but the battery draw has gone up to 1800 to 1850 mah. Just thought I would share with the group.

Bob Redmon

Title: Re: APC 11x5.5 changed as well
Post by: Dean Pappas on January 29, 2012, 09:32:02 AM

Thanks, Bob.
    Dean P.

Title: Re: APC 11x5.5 changed as well
Post by: john vlna on January 29, 2012, 12:49:11 PM

Bob,
Have you tried APC directly? They still list the 11x5.5 thin electric. Of course now that you changed to a new prop ....................
http://www.apcprop.com/ProductDetails.asp?ProductCode=LP11055E

Title: Re: APC 11x5.5 changed as well
Post by: Robert Redmon on January 29, 2012, 05:18:33 PM

John,

The new version is marked (and listed) in exactly the same way as the old. They are both called "thin/electric" I inadvertently got a couple of the new ones from my LHS and got a couple more from Tower. I hadn't pay any attention to them until yesterday. I just assumed they would be the same as the ones I had gotten in April from Brodak. The difference appears that the hub and the blades are thicker. The hub is noticeably thicker...about .1" thicker. They appear to have reduced (filled in) the undercamber to add material and increase blade strength....(IMO...not needed in our application). That effectively reduces the pitch. They apparently did the same with the 12/6 (thin electric) which is also still marked as the same prop but isn't. I experimented with pitch on the 12/6 thin electric props last summer when I discovered the ones I had wouldn't fly my airplane at the RPM everyone was citing. I marked the pitch I ended up with on my Prather pitch gauge and used the same setting to repitch the 11/5.5 yesterday. It shows about 5.5 at the #10 station on the Prather, but that represents about an inch more pitch than they are coming from the factory marked 5.5.

Bob

Title: Re: APC 11x5.5 changed as well
Post by: Dean Pappas on January 29, 2012, 05:23:09 PM

Friends,
I suspect that product liability will almost always trump our having thinner, lighter injection molded props.

take care,
  Dean

Title: Re: APC 11x5.5 changed as well
Post by: Dennis Adamisin on January 29, 2012, 05:33:18 PM

Bob:
Sounds like you are running the tractor version?  APC changed all their electric props.  The nice thin (and flexible) blades we got used to are now history.  The new props will work fine but as you noted you have tor run some 800-1100 RPM faster to get the same airspeed.

Next best step might be to get a 12x6, the 12x6.5 WEP or a 13x6.5 and clip it to 11" dia.  That should let you lower your RPM some, the wider blade should give somewhat better thrust and braking than the 11x5.5 too.

Title: Re: APC 11x5.5 changed as well
Post by: Robert Redmon on January 30, 2012, 06:30:21 PM

Thanks, Dennis, but prop clearance is already an issue with the 11" prop.  I have reached a reasonable compromise between pitch, lap time, and energy use, but I sure don't like them as well as the original APC thin/e props. They aren't balanced as well either.

Bob

Title: Re: APC 11x5.5 changed as well
Post by: Keith Renecle on January 30, 2012, 09:17:06 PM

Hi Bob,

I see that the Chinese copied the APC thin electric props and they are available from Hobby Kings:
http://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?idCategory=212

Maybe they will work for you until Dennis influences APC again to make a better 11 x 5.6 or maybe a 6 wide blade.

Keith R

Title: Re: APC 11x5.5 changed as well
Post by: John Rist on January 31, 2012, 03:21:01 AM

However no EP  just E :'(

Title: Re: APC 11x5.5 changed as well
Post by: Dean Pappas on February 01, 2012, 07:14:18 PM

Quote from: Keith Renecle on January 30, 2012, 09:17:06 PM

Hi Bob,

I see that the Chinese copied the APC thin electric props and they are available from Hobby Kings:
http://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?idCategory=212

Maybe they will work for you until Dennis influences APC again to make a better 11 x 5.6 or maybe a 6 wide blade.

Keith R

Would you look at that  HB~> pirated intellectual property and they actually have the nerve to say APC-style!
Thanks for the heads-up, Keith.

     Dean P.

Title: Re: APC 11x5.5 changed as well
Post by: Chris McMillin on February 23, 2012, 11:57:14 PM

Do you and Hunt hand out with Metallica?
Chris...