Graupner Vs APC prop observations  
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All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> Glow Engines >> Graupner Vs APC prop observations
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Graupner Vs APC prop observations - 1/23/2008 11:28:31 PM   
CustomPC


 

Posts: 280
Joined: 4/19/2004
From: SydneyNSW, AUSTRALIA
Status: offline 		Yesterday i did some testing with two 14x7 props on my OS .91 Surpass II and GP Super Skybolt.

On the ground the Graupner was getting on the low-mid 8,000's whilst the APC peaked at 9,200rpm.

In flight it was a different story. The APC was smooth but just didn't seem to have the "pull" of the Graupner. There was noticably less vertical with the APC and it didn't perform as well at low throttle settings.

The Graupner pulls like a tractor, from low through to WOT and the accelleration of the model was much better. The vertical was impressive, not unlimited but not far off it.

The top speed of the plane with both props was close. The APC had a slightly higher top speed but the perception from myself and 2 other observers was the Graupner feels faster due to the quicker accelleration and shorter time to reach top speed.

I've read posts from several respected forum members here regarding Graupner props and now that i've seen it and felt it i have to agree.
       Post #: 1

RE: Graupner Vs APC prop observations - 1/23/2008 11:50:31 PM   
rainedave



Posts: 4306
Joined: 7/21/2005
From: Greensboro, NC, USA
Status: offline 		Thanks for the report, CustomPC. I recently bought a handful of NIP Graupners really cheap and have been wanting to try them. I'll definitely put them on a couple of my planes and give them a spin.

David

(in reply to CustomPC)
       Post #: 2

RE: Graupner Vs APC prop observations - 1/24/2008 12:22:39 AM   
fiery


 

Posts: 1003
Joined: 2/2/2002
From: Hervey Bay Queensland, AUSTRALIA
Status: offline 		Are the props tested the old style grey "Super Nylon" Graupner props, or the new "scimitar style" "Sonic" Graupner props?

< Message edited by fiery -- 1/24/2008 3:08:45 AM >

(in reply to rainedave)
       Post #: 3

RE: Graupner Vs APC prop observations - 1/24/2008 12:59:23 AM   
CustomPC


 

Posts: 280
Joined: 4/19/2004
From: SydneyNSW, AUSTRALIA
Status: offline 		It's the old Super Nylon prop. ModelFlight (the Aussie Graupner agents) don't have the smaller sizes listed for the Sonic's yet but i wouldn't mind trying them when/if they do.

I think MF won't be bringing in the SuperNylons any more. I also wanted to try the 13.5x8 and compare it with the Bolly clubman of the same size. MF said the 13.5x8 is out of stock and no longer available.

For the record the Graupner need a little bit of work to balance. Just some sanding of the mould flashing around the edges, a minute amount of the tip and a light sanding of the forward face of the heavy blade got it balanced nicely.

The APC was perfectly balanced and just need the mould flashing sanded off.

< Message edited by CustomPC -- 1/24/2008 1:02:48 AM >

(in reply to fiery)
       Post #: 4

RE: Graupner Vs APC prop observations - 1/24/2008 3:11:42 AM   
fiery


 

Posts: 1003
Joined: 2/2/2002
From: Hervey Bay Queensland, AUSTRALIA
Status: offline 		I have a collection of 2 and 3 blade Gruapner Super Nylon props. Love them. Balance up quite easily, just like you say.

My opinion: Very hard to break a tip, look like a "real" prop, and perform far better than you may expect at first blush ...

I bought my first (an 11 x 6) in 1990 for $5.00, full retail price.

Those were the days


(in reply to CustomPC)
       Post #: 5

RE: Graupner Vs APC prop observations - 5/2/2008 4:42:48 PM   
oneqwk96gt


 

Posts: 13
Joined: 1/30/2008
From: mason, MI, USA
Status: offline 		CUSTOMPC,
I GOT THE SAME RPM READINGS WITH MY OS 91FS2 ON MY SUPER SKYBOLT, GRAUPNER 14-7 TURNS 8400-8600. IDLES RELIABLY AT
1600RPM, I HAVENT TRIED ANY OTHER PROPS IN FLIGHT BUT THIS COMBO IS IMPRESSIVE ON THE SKYBOLT. JUST THIS WEEK FLEW FOR 23MINUTES AND STILL HAD SOME FUEL LEFT. ON A CALM DAY I CAN HANG ON THE PROP AT HALF THROTTLE. I TOTALLY AGREE WITH YOUR ORIGINAL POST AS I HAVE BEEN LOOKING FOR SOMEONE ELSE TO SEE IF THEY HAD TRIED THIS PROP/ ENG COMBO AND WHAT THEY WERE TURNING FOR RPM. SOUNDS LIKE WE HAVE THE SAME RESULTS. -AARON-

(in reply to fiery)
       Post #: 6

RE: Graupner Vs APC prop observations - 5/2/2008 6:41:18 PM   
spiral_72



Posts: 348
Joined: 3/7/2007
From: Chesnee, SC, USA
Status: offline 		Thanks for the post. As luck would have it, I've been considering trying the Graupner props.

They do look nice!

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(in reply to CustomPC)
       Post #: 7

RE: Graupner Vs APC prop observations - 5/2/2008 7:15:53 PM   
digital_trucker



Posts: 981
Joined: 2/4/2006
From: Dorr, MI, USA
Status: online 		I run exclusively Graupner Super Nylon props, on everything from 1/2A up my nice shiny new .91 Surpass. I long ago discovered through comparative flight testing that nothing else pull s like a Graupner grey. APC turns faster, but the proof is in the flight. The only prop I've ever used that compares to the Graupners are the old Top Flite Super M props. INterestingly enough, the Graupner Super Nylons look an AWFUL lot like the TF Super-M's.

I've only ever broken one Graupner prop....and that was due to 'landing' on the spinner.

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(in reply to spiral_72)
       Post #: 8

RE: Graupner Vs APC prop observations - 5/2/2008 9:01:07 PM   
Jim Thomerson



Posts: 2718
Joined: 10/9/2002
From: Austin, TX, USA
Status: offline 		I tried both Graupner and APC 11 x 6 props on a dieselized Tower 40 on a control line stunt model. I thought the APC was noticably better in flight through maneuvers. Not too much difference, however.

(in reply to digital_trucker)
       Post #: 9

RE: Graupner Vs APC prop observations - 5/3/2008 1:12:27 AM   
Hobbsy



Posts: 10129
Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: offline 		I have been using them since about 1991. I use a few Bollys now too.

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       Post #: 10

RE: Graupner Vs APC prop observations - 5/3/2008 9:42:55 AM   
David Bathe



Posts: 19
Joined: 3/18/2008
From: Oslo, NORWAY
Status: offline 		I'm surprized that nobody has mentioned engine RPM's because they're the reason your engine/aircraft combo is performing better with the Graupner... not the prop!
The Teutonic blades are causing your engine to operate in it's high torque band... low-mid 8s rpms. Thus you're getting the "tractor" pulling power you mentioned.
Because the APC is more efficient, it allows the engine to rev far higher even though it's the same size. As you've found out, high revs aren't necessarily the answer to great performance, high torque is.
So what does all this mean? Quite simply that you can go a size bigger with the APC... possibly two, you'll have to experiment.
Add an inch to the APC diamiter or even two and trim it back some... what ever, just end up with the R's about the same No's as with the Graupner.
You'll experience a mighty increase in pulling power.

< Message edited by David Bathe -- 5/3/2008 3:01:56 PM >

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Best Regards: David Bathe, Aircraft and Instrument Panel Illustrations.

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       Post #: 11

RE: Graupner Vs APC prop observations - 5/4/2008 5:25:41 PM   
Mr Cox


 

Posts: 192
Joined: 7/20/2007
From: Gothenburg, SWEDEN
Status: offline
quote:

ORIGINAL: David Bathe

Because the APC is more efficient, it allows the engine to rev far higher even though it's the same size.


Well that's what the advertizing says... [)]

If the engine revs higher and the pull is less then it is simply a smaller prop with the same numbers marked on it...

(one could then compare the graupner with a "larger" APC with similar top revs and see how that flies)

< Message edited by Mr Cox -- 5/4/2008 5:26:29 PM >

(in reply to David Bathe)
       Post #: 12

RE: Graupner Vs APC prop observations - 5/8/2008 7:54:33 AM   
CustomPC


 

Posts: 280
Joined: 4/19/2004
From: SydneyNSW, AUSTRALIA
Status: offline 		Has anyone tried the Graupner CAM props?

An on-line shop here was clearing old stocks of Graupner props and i ordered an 11x8 Super Nylon but the sent me a black 11x8 CAM prop.

I'll probably keep it because it was cheap but i'd be intereseted to know how it compares to their Super Nylon or the APC's.

(in reply to Mr Cox)
       Post #: 13

RE: Graupner Vs APC prop observations - 5/8/2008 8:08:38 AM   
jaka


 

Posts: 4239
Joined: 12/11/2001
From: Upplands Vasby, SWEDEN
Status: offline 		Hi!
Yes! They are better than the old grey Graupner props.
The old grey ones arn't particularly good. Loots of noice and not that good pulling power.

Anyone tried the British "RAM" line of props? Try them! They are very good!


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(in reply to CustomPC)
       Post #: 14

RE: Graupner Vs APC prop observations - 5/8/2008 12:53:08 PM   
Jezmo



Posts: 644
Joined: 6/26/2006
From: Spring, TX, USA
Status: offline 		Who handles Graupner