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Engine basics => Engine set up tips => Topic started by: Alex Poperechny on January 16, 2011, 03:16:18 PM
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Hi Guys!
I would like to ask the following question. Now pusher props are popular with ECL guys.
Why IC guys do not use clockwise rotation engines?
Thanks.
Alex -
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Hi Guys!
I would like to ask the following question. Now pusher props are popular with ECL guys.
Why IC guys do not use clockwise rotation engines?
Thanks.
Alex -
I believe it is because there are very few engines that will run clock wise and good props are not easy to find.
Enya has the reverse crank for a few of their engines. I have one for my Enya SS50 but not sure if that part is still available. The problem is that I will need to make a prop for it, there is nothing out there that would work. The only prop that come close is the JXF 14x 4 that would need to be cut to 12.5~13
FOX also have reverse cranks for some of their engines. I don't see it on the website for the FOX 35 but I guess if you call them they may be available.
I am not 100% sure, but seems there are some optional reverse cam gear for the Saito 62 and 72
Enya 53-4C is easy to setup for reverse rotation and there is a good prop for it in pusher mode the JXF 13x6
Martin
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I would like to ask the following question. Now pusher props are popular with ECL guys.
Why IC guys do not use clockwise rotation engines?
Very few good props.
Brett
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I wrote some of the engine manufacturer and here are some answers.
=== from Stalker ===
No, we're doing this ...
=== from Enya ===
The following reversal crank shaft are available.
cross flow model
09-4
15-4
19-6
29-4
40,45-2
60-3B
20
Xseries
25X
40X
45X
60XF-II
CX,SSseries
11CX
ULTRA11CX
SS15BB
SS25
SS25BB
SS30
SS40
SS40
SS50
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Thank for that Alex! I didn't know Enya had so many reverse cranks.
The JXF props are in my opinion the best wood props you can buy, specially the electric ones which I got every body using down here, total success. JXF has pusher props in these sizes:
13x6 which would work well on the Enya 60III and Enya 53-4C
12x6, 12x5 and 11x6 for the Enya 45 Cross Flow models 6002 and 6001
and these would be the props size I would definitely use with the regular crank for those engines any way.
The JXF 11x5 cut to 10.5" may work well on the Enya SS30, although I find hard to beat the APC 10.5x4.5 for this engine.
Martin
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Just learn to fly clocwise. It is interesting to do.
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=== from FAQ of www.osengines.com ===
Does OS make an engine with a counterrotating crankshaft or a means to convert an engine to counterrotating?
No, OS does not produce an engine with a counter rotating crankshaft. Until 2 years ago we stocked a reverse camshaft for the smaller OS four strokes to allow you to do this, but these are no longer available either. A standard engine cannot simply be 'reversed' in any means. However, you could go to a gear reduction system for both your engines with the reverse direction engine having one more or one less gear in the gear train. However, we are not aware of anyone who makes a product specifically for this task.
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A little know fact regarding engine with removable front housing like Enya's -
"Its not generally known that an ENYA engine with the bolt - on front housing can very easily be made to run in reverse, simply by rotating the front housing 90 degrees to the right ( when viewed from the rear of the engine ). Why would you want to do this ? Well, I' ve been wanting to fly a C/L model with 3 line throttle control ever since I was a kid, and the information I' ve gathered suggests that an engine turning in the opposite direction to normal is highly desirable, as sudden throttling up will usually cause the model to bank in on the lines, due to torque reaction in an anti - clockwise ( viewed from the front ) turning motor. So, I contacted my ENYA friend in the States who is an engineer, Pat King, and asked him to check the shaft timing on an ENYA 35 - lll B, firstly with the intake upright as delivered from the factory, then with the shaft housing rotated 90 degrees to the right hand side of the engine - here are his findings
ENYA 35 - lll B shaft timing, normal configuration - With housing on the side ( reverse rotation )
Port opens at 48 deg. ABDC Port opens at 46 deg. ABDC
Port closes at 48 deg. ATDC Port closes at 50 deg. ATDC
Pat says that " The timing is so close that a dynometer is probably the only thing that could detect the horsepower difference ". Obviously, the shaft timing duration remains the same, so 5 minutes with a screwdriver and you can convert your ENYA to run in reverse ! Don' t forget to bolt on a pusher prop."
Gained from this site -
http://www.supercoolprops.com/articles/enya.php
But something to watch out for is De Sax cylinder axis offset that will only work in on direction of rotation and perhaps venturi offset as seen on the likes of Super Tigres and MVVS engines although I doubt that this will adversely affect much.
If using a clockwise rotation be sure to visit up thrust as a trimming aid as opposed to down thrust when using the conventional anti-clockwise props.
Cheers.
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Chris,
Thanks for passing that along. I once - 50+ years ago - did set up an ENYA 29-III for clockwise and noticed very little power difference from stock CCW running. I've also flown Fox 35s with the factory CW shaft, with equal success.
The concern remains, for other engines, that the shaft intake timing does not mirror as well at the ENYA Pat measured... In that case, there's likely to be a loss of power or manners converting an engine designed for CCW. The mfrs most likely develop for optimum in stock (CCW) rotation. Change away from optimum seems to define itself, no?
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I believe that MVVS offer reverse rotation cranks on all their internal combustion engines also, but I am wondering if placing the side forces from the power stroke against the exhaust porting may be a bad thing - you know, combining the hottest part of the engine with the highest wear point type of thing.
Racing motorcycles get away with so I guess it can be engineered for though.
I have seen clockwise electric engines in stunt models that really pull hard away from the pilot just after leaving the ground, and that's a good thing.
The torque roll ensures line tension at a time when it could be very low.
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K&B used to do them for Carrier , apparently wasnt unpopular for that on the Torpedo 40s.
They also listem for the K&B Veco 19s .Usefull for floatplanes too.
Stepping back to maintain tension can have drawbacks flying over water.
Tornado / grish did a lot of there Nylon Props as L.H. , inc 3 blade .
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Latest News.
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The following manufacturers have answered me that do not produce a clockwise crankshafts.
In brackets engines that I have asked.
www.mvvs.cz (MVVS 8.0 Akrobat - 3077A)
www.foxmanufacturing.com (FOX 35 STUNT 50th Anniversary Edition)
www.aeroproduct.net (Precision Aero Engines)
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www.jettengineering.com (Dub makes a clockwise crankshafts for Ro-Jett engines)
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Thanks.
Alex -
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I'm waiting the run the Fox .35 which I have put a reverse crankshaft in on my All American Sr. I did so in hopes to aid "take off' since the AA Sr. has three inches of asymmetry built into the wing. This causes a bit of "trying to turn in on take off", and I can't run quite as fast as I used to . ;D
Big Bear
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For what its worth, I have communicated with the Reps for XOAR props, they will make any of their props in a reverse config, there is a charge and minimum order for this but they are available. While they arent Carbon, or what you typically see on stunt ships, they are very popular with RC guys who want good performance from a wood prop.