RE: Profi toy

RE: Profi toy
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RE: Profi toy - 5/7/2008 5:23:34 PM

MJD

Posts: 1487
Joined: 5/27/2003
From: Orangeville, ON, CANADA
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quote:

I wish I knew where to get a square, or at least high pitch single blade prop. I know CS used to sell them, but after having a few of their engines I wouldn't want to trust a one-blader made by them. I was able to make a 1 blade prop from the Graupner CAM 4.7-4.7, but never got it completely balanced dynamically. It just needs some time, it was done for NATS testing in the final days prior to leaving.

From supercool propellor's site:

1/2A Single blade 5.9 x 4.8 counterweight C/F
1/2A Single blade 5.8 x 5.0 counterweight C/F
1/2A Single blade integral spinner 5.9 x 4.8 C/F
1/2A Single blade integral spinner 5.8 x 5.0 C/F

There are jpgs of the last two on the site. No doubt these could be trimmed and rebalanced.

While I am not sure about their ability to handle the revs, MA makes a 5.5-4.5.

MJD

(in reply to DeviousDave)

Post #: 26

RE: Profi toy - 5/8/2008 4:31:30 AM

DeviousDave

Posts: 376
Joined: 2/25/2007
From: , MI, USA
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The single blade props on SuperCool's sight might be a bit much-The Aussies idea of 1/2A Pylon uses .10 sized motors like the OS .11CZ-P, which doesn't mind a 6" diameter.

Worth a shot though. I'll have to check my notes and see what the 4.7-4.7 one blader and compare it to the full prop to see the difference in load. I want to say that it was in the 60-70% range If you go strictly by amp draw, but I have W-in written down too IIRC.

I was trying to find a way to make the 4.8V Sp400 motor last on 7 cells. Eventually ended up with a real barn burner by dropping to 6 cells and using a 4.5 4.2. The thing was Wicked Fast, but the motors only lasted 2 flights. Hey, it's an improvement over the original 30-seconds-to-smoke I started. It would have become "the hot setup", but they stopped racing 400 pylon at the NATs the year after that.

(in reply to MJD)

Post #: 27

RE: Profi toy - 5/8/2008 4:43:35 AM

MJD

Posts: 1487
Joined: 5/27/2003
From: Orangeville, ON, CANADA
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quote:

ORIGINAL: DeviousDave

The single blade props on SuperCool's sight might be a bit much-The Aussies idea of 1/2A Pylon uses .10 sized motors like the OS .11CZ-P, which doesn't mind a 6" diameter.

Worth a shot though. I'll have to check my notes and see what the 4.7-4.7 one blader and compare it to the full prop to see the difference in load. I want to say that it was in the 60-70% range If you go strictly by amp draw, but I have W-in written down too IIRC.

I was trying to find a way to make the 4.8V Sp400 motor last on 7 cells. Eventually ended up with a real barn burner by dropping to 6 cells and using a 4.5 4.2. The thing was Wicked Fast, but the motors only lasted 2 flights. Hey, it's an improvement over the original 30-seconds-to-smoke I started. It would have become "the hot setup", but they stopped racing 400 pylon at the NATs the year after that.

Yeah, I think they would be too much load stock too, but trimming to 4-3/4" - 5" and rebalancing shouldn't be too bad a job. They're a start anyway.

Hmm.. I just looked and Bolly has a 5-5 CF prop. That sounds about right.

MJD

(in reply to DeviousDave)

Post #: 28

RE: Profi toy - 5/16/2008 10:53:56 PM

Japanman

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Joined: 4/6/2003
From: Tsu, JAPAN
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Toad,
Any updates on the engine?

J.M

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Post #: 29

RE: Profi toy - 5/17/2008 12:03:45 AM

Toad

Posts: 405
Joined: 12/3/2001
From: Hurricane, UT, USA
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I did run the Profi but I have not ran all the engines in a head to head yet. I still need to make a mount for the Cyclon on the bench (its in a plane)
I was impressed, I ran 4oz thru the profi of 40% it holds great right at 36k flat on a 4.4x2.8 It blew the plug first two runs, I had to add a gasket for the last two runs. The Cyclon mounted on the plane, same prop, 35,600
Im pleased.

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Post #: 30

RE: Profi toy - 5/17/2008 12:06:17 AM

Toad

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From: Hurricane, UT, USA
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I think with a little tinkering, the Profi will live up to the rumours about it. the thing starts very easy, I struggle a bit getting used to the bladder thing. I'll get there.

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Post #: 31

RE: Profi toy - 5/17/2008 1:28:00 AM

combatpigg

Posts: 9199
Joined: 11/22/2003
From: arlington, WA, USA
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I'm amazed that there are enough guys into high performance 1/2A to keep Cyclon, Fora and Profi afloat.
Slight differences in rpm are meaningless with relatively low pitched props and a given amount of drag, unless you are trying to make up a second in time that you flubbed away on the last lap]. The differences in actual mph will be slight.
At this level of performance what matters most to me is consistency and reliability.

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Post #: 32

RE: Profi toy - 5/17/2008 2:10:40 AM

DeviousDave

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From: , MI, USA
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quote:

ORIGINAL: combatpigg

I'm amazed that there are enough guys into high performance 1/2A to keep Cyclon, Fora and Profi afloat.
Slight differences in rpm are meaningless with relatively low pitched props and a given amount of drag, unless you are trying to make up a second in time that you flubbed away on the last lap]. The differences in actual mph will be slight.
At this level of performance what matters most to me is consistency and reliability.

You have to remember that these motors are made for CL and FF, where the differences between planes and setups are very minor. Everyone builds the same kind of airplane, to the same weight. There are a lot fewer places to add in Human Error-with pylon you have 30 opportunities to screw up yer heat, Free Flight? Timer set? Fuel in the line? Start motor and let go. CL Combat? 1 or 2 MPH can be the difference in kills if you can't dice it up well.

I'd say that the reasons we can buy 3/4hp 1/2A's these days is because the motors are one of the few things that can be improved in FF and CL and used as an advantage on an adversary or competitor.

< Message edited by DeviousDave -- 5/17/2008 2:11:23 AM >

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Post #: 33

RE: Profi toy - 5/17/2008 3:19:58 AM

combatpigg

Posts: 9199
Joined: 11/22/2003
From: arlington, WA, USA
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I don't know [anything] about free flight, but it makes sense to have every advantage there. With 1/2A Cyclon combat, the matches that I've flown and witnessed aren't full of lengthy chases where a thousand rpm makes a consistent difference or guarantee of victory. The models are already doing about 90 mph with 3 pitched props so a difference of 3% in rpm will make way less than 1% difference in model speed.

BTW, the cocked venturi would complicate designing a streamlined model, does Profi have a current version with the venturi lined up with the cyclinder?

< Message edited by combatpigg -- 5/17/2008 3:29:06 AM >

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Led Zeppelin is NOT "old fogie" music.

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Post #: 34

RE: Profi toy - 5/17/2008 4:19:49 AM

Toad

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From: Hurricane, UT, USA
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In my opinion, a 3% gain is significant and should be sought after in any racing application.
My intent was to just share the numbers I get from the engines
using what I fly with. By all means I would love to see someone else do a similar thing with the props and fuel they prefer
I like the offest venturi design, It has its advantages and cowling one shouldnt be any harder to do than a regular engine, Just the hole is
offset 90 deg, Anyway, different strokes for different folks I guess.
So, I like the engine, the price I think is fair in comparison with the Fora
I'm done

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Post #: 35

RE: Profi toy - 5/17/2008 6:29:54 AM

DeviousDave

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The 90 deg. intake venturi follows late trends with FAI .15 combat. Cyclon even makes them with reverse venturis to keep dirt out of the motor when you plant it. Not sure what the purpose is for 90 degree rotation.

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Post #: 36

RE: Profi toy - 5/17/2008 6:40:16 AM

Toad

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From: Hurricane, UT, USA
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For me, when I built my own engine, it was to keep the fuel line on the left side of the engine , on top when side mounted so the side exhaust didnt heat the fuel in the line going to the venturi and the fuel line is more convenient to get to, a side benifit is the intake window on the crank, it is more directly opposite the counter weight, that helps in the balance, the engine runs smoother, hence some rpm gain is the result. Of course on landing, it is also less prone to get dirt in the venturi if you mount the engine on it's side. On my latest engine, I am putting in a pressure nipple on the left side also, so tank filling will be easier and I wont have to use a bladder or run the pressure from the back plate where the vent line is harder to deal with. I like the idea, makes things way user friendly.

< Message edited by Toad -- 5/17/2008 6:43:00 AM >

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Post #: 37

RE: Profi toy - 5/17/2008 6:40:24 AM

combatpigg

Posts: 9199
Joined: 11/22/2003
From: arlington, WA, USA
Status: online

I've never tried pitting a 90 degree out engine, it must have some advantages or they wouldn't use it. As far as less dirt taken in after a crash, that is entirely up to the Ground Gods.

_____________________________

Led Zeppelin is NOT "old fogie" music.

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Post #: 38

RE: Profi toy - 5/17/2008 4:16:17 PM

Toad

Posts: 405
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From: Hurricane, UT, USA
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Pig, you are bumming me out!
So negative man, Best not to talk about crashing.

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Post #: 39

RE: Profi toy - 5/17/2008 4:37:55 PM

combatpigg