Author Topic: new APC 12x6 props (Read 2544 times)

Igor Burger · « **on:** May 16, 2011, 07:10:01 AM »

I heard that APC sales new typ of APCE 12x6 prop. The hub is taller 13mm instead of 10mm and with little less pitch and especially flat airfoil. It all leads to ~800 rpm more for the same lap time. Is that true? Anyone has the same experience? Is it another type? Or new design instead of older? I did not see them yet. But affraid that I must to buy box of those old to be sure I have enough backup props :-))))

WhittleN · « **Reply #1 on:** May 16, 2011, 10:22:29 AM »

Hi Igor

I have some experience with APC props. I liked their 11.5 x 4 regular props on the VF 40/46. The 4 " of pitch was too much, so like a CF prop, I heated them in boiling water and re-pitched to 3.6". I found it takes several minutes in the boiling water (much more than CF) but once I twisted in the pitch it held much better and longer than CF props. Maybe you would want to try this on the 12 x 6’s.
Regards
Norm

Igor Burger · « **Reply #2 on:** May 16, 2011, 10:28:13 AM »

Thanks Norm, but that is is not what I need. The point is to know if APC changed those props somehow ... and if yes, if those old are discontinued. Because I really canot play with every prop in boiling water, what we need, is to buy and use as was used that prop before, not to be badly surprised with a lap 6s instead of 5.3 when I change the prop :- )))

WhittleN · « **Reply #3 on:** May 16, 2011, 10:35:14 AM »

Oh how quickly we forget how we used to screw around with props in our IC days. Hope it works out for you.

Norm

Igor Burger · « **Reply #4 on:** May 16, 2011, 10:45:29 AM »

The beauty of the electric power train is its ability to post complete setup by email, so that the model works well for first try, but if we have 2 types of a component called "APCE12x6" then it is very difficult. It can even happen that the diffence in the pitch can cause another number of cells, and it can really make problem. I sent several complete combos already set for proper lap time and it allowed many new e-pilots to fly without pain of burned or damaged components for first try. If this message is true, that it WILL make problem. So that is why I am asking - not to confuse someone with improper information.

Dean Pappas · « **Reply #5 on:** May 16, 2011, 01:18:15 PM »

I'll see what I can find out.
Dean P.

Dennis Adamisin · « **Reply #6 on:** May 16, 2011, 07:57:36 PM »

The following was explained to me by a representative of APC, when I was ordering the new 11" pushers last year. I reported this when we created the new 11x5.5P. For the complete story including a station by station of the 11x5.5 thin blade versus 11x5.5P thick blade see:

http://stunthanger.com/smf/index.php?topic=19119.0

A little over a year ago APC began redsigning the entire electric prop series. They added substantial material to the hub and base of the blade to improve the rigidity and strength. APC claimed that because of the increased blade stiffness the props required less current at a given RPM.

MY speculation is that the thin blades actually flexed extra pitch in. The stiffer prop must spin faster to get back to the thin prop speed and current draw.

When the new 11x5.5P props came in last summer they exhibited the new (thickened) design philosophy and required rough 500 RPM more than the then blade RH counterparts.

BTW - I share Igor's opinion that repitching props is undesirable - at the very least repeatability goes out the window...

Igor Burger · « **Reply #7 on:** May 17, 2011, 02:01:14 AM »

I actually got that prop to hands, it is really as I wrote. The hub is taller and the difference is clearly visible. The prop is also heavier, the airfoil is almost flat on lover side and the pitch is ~1/4" less than older prop. So it will certainly need at least 500rpm more.

bob branch · « **Reply #8 on:** May 17, 2011, 07:02:50 PM »

Man, this is a bummer. I'm off to my LHS Saturday morning to see if he has any of the old ones. This is the primary prop for an axi 2826/12 system. That many more rpm will rule out make 4S systems difficult.

bob branch

Dennis Toth · « **Reply #9 on:** May 20, 2011, 03:04:32 PM »

Guys,
It would be interesting if someone has one old and one new prop to try and see what the lap time and amp draw difference is at the same rpm. Then set one of the new ones up to higher pitch to match the lap time of the older prop and see the difference again. It is likely that there won't be much change. Now if you increase the rpm to match the lap time I would expect to see more amps drawn down.

Best, DennisT

Howard Rush · « **Reply #10 on:** May 20, 2011, 05:45:49 PM »

Have they revised the 13-4.5?

Crist Rigotti · « **Reply #11 on:** May 20, 2011, 06:27:42 PM »

Quote from: Howard Rush on May 20, 2011, 05:45:49 PM

Have they revised the 13-4.5?

Howard,
I just received 3 13x4.5EP props directly from APC a few days ago. They are not modified, they are exactly the same as my other 13x4.5EP props.

Igor Burger · « **Reply #12 on:** May 23, 2011, 01:18:41 AM »

So after all I tested those new props, It needed 10 000rpm instead of 9000 and the consumption was aproximately the same. The speed stability was little bit better, but the noise was terrible ... high tone like piped model

bob branch · « **Reply #13 on:** May 23, 2011, 05:41:02 AM »

Well, that much of an rpm increase could certainly force an engine or battery change depending on your setup. They certainly seem to have not done any favor to us in this change. What's it with these companies that they cannot leave something that works so well alone?

bob branch

Steve Helmick · « **Reply #14 on:** May 23, 2011, 09:25:41 AM »

Seem to recall that the owner of APC died last year. Whoever took it over is probably more concerned about liability than the performance of your stunter. From their (balance sheet) point of view, all they have to do is be better than MAS and Zinger. So, APC can afford to degrade performance quite a lot, all in the name of reduced liability exposure. That's my bet. It's surprising to me that anybody makes & sells propellers, with the liability issues and how lawsuit-happy people are these days.

Steve

Keith Renecle · « **Reply #15 on:** May 25, 2011, 09:39:26 AM »

This is serious hassle for many of us. The 12 x 6 E-prop is like a standard for the .50/.60 size stunters. Maybe we can twist Dennis's arm to speak to APC. He seems to have a connection with them. If enough of us contact them after this, then maybe they will see the problem and rectify it. How about it, Dennis??

Keith R

Dennis Adamisin · « **Reply #16 on:** May 25, 2011, 10:38:23 AM »

I am in the process of moving and have no internet access except by SmartPhone - which is tedious to type please bear with me...!

I think the answer is to start special ordering some new sizes in higher pitch to counter the effect of the new thick blade designs

* a new 13x5.5P to replace the thick 13x4.5 P

* a new 12x7P (?) To replace the thick 12x6P

From what I have seen or read we will need about 1" additonal pitch.

Feed back anyone?

bob branch · « **Reply #17 on:** May 25, 2011, 10:46:10 AM »

Dennis

I agree with you. These are our workhorse props. I have 3 or 4 of each, but I think you have the solution to the problem. It would be helpful to have a test prototype or two to test before they start production. Rick Sawicki and I could test the 12X6P replacement since we use that size so much and have so much data on various planes with it if you need testers.

bob branch

Igor Burger · « **Reply #18 on:** May 25, 2011, 11:20:55 AM »

Yes Dennis, I think the 12x8 will work, but you must remember that there IS a difference. While the pitch speed difference is because of UCT airfoil on old props, and new 12x8 prop has flatter arirfoil with more pitch and thus AoA in the air, the pitch speed can be aproximately same, but static thrust will be probably lower on 12x8 with flat airfoil, because that UCT airfoil on old prop can make more lift at its critical AoA. So I expect that the new prop cannot keep the speed as well as the olp prop did. It is only my guess, but I will be very surprised if I am wrong :- )))))

I think it will be much better to redesigh the power train to that new 12x6 at higher rpm then to use 12x8. May be it is even better to use new 13x6,5 instead of old 12x6. The rpm difference will be certainly smaller that with new 12x6. And IF it loads too much then we can still make it shorter.

Keith Renecle · « **Reply #19 on:** May 25, 2011, 11:31:43 AM »

I also tried the ZOAR 12 x 7 wood prop and I run it about 400 rpm less........if I remember correctly. It's a good prop. I still believe that it is in APC's best interest to let them know what the users think, especially if the measured pitch is actually less than the old props. Maybe they will do the corrections.

Keith R

WhittleN · « **Reply #20 on:** July 11, 2011, 06:26:47 AM »

Guys
Just tried the new APC 13 x 4.5 thick hub. Went from a 5.35 lap on my settings to a 5.96 second lap. It will take 600 RPM to regain the lap times. Like Dennis said above and extra inch of pitch is needed. Anyone have any thin hub 13 x4.5 APC Pusher props they want to sell?

Norm

Crist Rigotti · « **Reply #21 on:** July 11, 2011, 06:54:50 AM »

Norm,
Where did you get the thick hubbed prop?

WhittleN · « **Reply #22 on:** July 11, 2011, 09:01:01 AM »

Good morning Crist
Tower Hobbies but you can get them form me cheap. Or trade for thin 13 x 4.5 EP.

Norm

Keith Renecle · « **Reply #23 on:** July 11, 2011, 09:09:51 AM »

Just a thought...........would APC not produce the old props if there is a demand. I mean, surely they didn't get rid of the old dies. Maybe we can try this approach??

Keith R

WhittleN · « **Reply #24 on:** July 11, 2011, 09:30:58 AM »

Keith
Already sent e-mail to APC. Will keep folks posted if I get a response. I suspect they may have modified the mold but I could be wrong (I hope).
Norm

Crist Rigotti · « **Reply #25 on:** July 11, 2011, 10:15:46 AM »

Quote from: WhittleN on July 11, 2011, 09:01:01 AM

Good morning Crist
Tower Hobbies but you can get them form me cheap. Or trade for thin 13 x 4.5 EP.

Norm

Time to do some scrounging. I have 4 already, but from the looks of things more might be a good idea.
Thanks.

Keith Renecle · « **Reply #26 on:** July 11, 2011, 10:47:32 AM »

Quote from: WhittleN on July 11, 2011, 09:30:58 AM

Keith
Already sent e-mail to APC. Will keep folks posted if I get a response. I suspect they may have modified the mold but I could be wrong (I hope).
Norm

Thanks Norm, maybe we will get lucky. It's still a puzzle to me that they needed to fiddle with such winning props.

Keith R

WhittleN · « **Reply #27 on:** July 11, 2011, 11:52:11 AM »

Keith
Liability! Did you know the IC folks are trying to use them on their models? That is what all this is about.
Norm

WhittleN · « **Reply #28 on:** July 11, 2011, 02:33:20 PM »

As promised the APC response. Very encouraging - they are taking prompt action
”Hi Norm,
We are aware of this issue. By thickening the inner portion of the blade some camber was removed from the airfoil. Although the geometric pitch is unchanged, the aerodynamic pitch is less.
We are working with Dennis Adamisin to resolve this issue. I will have a prototype prop for him to test next week. Please contact him for more details. He will be distributing the new propeller when ready.
Regards,
Robert”

Norm

Crist Rigotti · « **Reply #29 on:** July 11, 2011, 03:57:23 PM »

Good news Norm.
Thank you.

Keith Renecle · « **Reply #30 on:** July 12, 2011, 01:27:40 AM »

Whoopee! Well done Norm, and thanks for your efforts. Thanks for pointing out the liabilty issue as well. I felt sure that APC would do something about this because they are so jacked up and like to stay on top of their game.

Thanks once again to Dennis for being there to test the stuff. Hope your move is done now and you can get back to normal again.

Keith R