Author Topic: Yatsenko pusher wood prop (Read 2646 times)

jose modesto · « **on:** January 06, 2012, 09:12:29 AM »

Got a chance to do some prop testing last week The model converted gas shark to electric Motor Platt 24-14
used the following props Yatsenko 13.4x6 pusher 13.4x6 tracktor and the apc 13x4.5 thin blade
the yatsenko props at 6 pitch 8,500 RPM
APC at 9,700
the wood yatsenko prop is larger in diameter than the APC also stiffer
The results were that the E shark at 70oz flew with more line tention above 45 degrees note prop is larger, below 45 no real advantage from the yatsenko
One item that was noticeable was the reduced prop noise wen flying the hour glass. The APC (original thin) flops overhead. Also less noise on every hard corner.
the Yatsenko props also come in 14"diameter.
Prop weight Yatsenko .8oz
APC thin .9oz the 13.5 wep 1.2oz
take a look at their E spinner
Jose Modesto

Dennis Toth · « **Reply #1 on:** January 06, 2012, 01:43:03 PM »

Jose,
Do you have an external rear or nose bearing on the motor setup?

Best, DennisT

jose modesto · « **Reply #2 on:** January 06, 2012, 06:48:04 PM »

Dennis. The motor is firewall mounted no additional support used. With the Plats i have used a firewall mount.
See photo
in an earlier thread, gas Yatsenko shark convertion to Electric there are photos of the complete conversion
Jose Modesto

Russell Bond · « **Reply #3 on:** January 08, 2012, 04:44:51 PM »

Jose,
I tried to email you but they bounced back.

Can you email me please.

Dennis Toth · « **Reply #4 on:** January 09, 2012, 12:35:19 PM »

Jose,
Did you try a tractor prop just to compare?

Best, DennisT

jose modesto · « **Reply #5 on:** January 09, 2012, 01:31:15 PM »

Yes Dennis I tried the tractor with similar results. Better above 45 but model requires lead out adjustment based on prop rotation.
I like a conventional bellcranck with the pusher props and a reverse bellcranck with the tractor. Since the bellcranck is difficult to rotate then other adjustments must be made to get optimum performance from the same model.
Jose Modesto

Dennis Toth · « **Reply #6 on:** January 09, 2012, 04:59:40 PM »

Jose,
I agree with your explanation, I found similar results on my profile ship. It has a front mount and I noticed a big difference on the inside maneuvers once I added the external rear bearing. Looking at your photo's it seems there is not much room to add a front bearing block (some have done this on the rear mount setups). With the light weight of the wood prop it seems to have less yaw impact. If you can try it on another ship it would be interesting to hear how it works with the rear mount setup.

Best, DennisT

Russell Bond · « **Reply #7 on:** January 09, 2012, 05:31:33 PM »

Jose,
On the Shark, did you use up-thrust on the motor?

Also, are the Yatsenko props for sale from you?

jose modesto · « **Reply #8 on:** January 09, 2012, 06:20:12 PM »

I'm not selling Yatsenko props
The beauty of fire wall mounting is that you can shim the motor to any angle.
Russell. I have an E shark built for me by the Yatsenko's it has motor off set but dint measure any down thrust. this model is also fire wall mounted.
See Photo
Photo #3 fire wall X mount. what you see is the ply wood X mount used as pattern for motor x Xmount. Yes u must make your own. For future models the x mount will be provided for the spec motor.
Jose Modesto

Crist Rigotti · « **Reply #9 on:** January 09, 2012, 06:55:47 PM »

Man, I'm drooling!

Derek Barry · « **Reply #10 on:** January 10, 2012, 05:55:34 AM »

Do you think mounting it to the firewall only will hold up over time? And the new props will fix what I considered to be the weak link in the electric program...

Derek

jose modesto · « **Reply #11 on:** January 10, 2012, 06:38:48 AM »

Derek I have 8 electric models all firewall mount.The only time a had any issues with motor run was while using the axi2826/10. Firewall mount and a weak fuse front end. The firewall mount was not installed properly and motor with firewall attached ejected from the model.
While using the platt,Eflite,scorpion,with firewall mount,I have had no issues. One caveat is that the firewall must be triangulated to the fuse for lateral support.
I'm interested in your observation as to the weakness of Electric power.please elaborate on this.
I have a built in advantage as my fuse is composite shell and I can insert reinforcement at critical areas while vacuum bagging.
Please elaborate on the weakness of electric power and your observations.
Were you able to see photo of horn install on SV22 TA
The Yatsenko props are stiffer at the tips,In my observation from actual use they make less noise.
Do you think that if gas models were as quiet as electric that we would hear the same prop noises?
With the pusher prop I hear more prop noise on outside maneuvers then switch to tractor and the prop noise switches to inside maneuvers.
Jose Modesto

Derek Barry · « **Reply #12 on:** January 10, 2012, 08:13:25 AM »

Quote from: jose modesto on January 10, 2012, 06:38:48 AM

Derek I have 8 electric models all firewall mount.The only time a had any issues with motor run was while using the axi2826/10. Firewall mount and a weak fuse front end. The firewall mount was not installed properly and motor with firewall attached ejected from the model.
While using the platt,Eflite,scorpion,with firewall mount,I have had no issues. One caveat is that the firewall must be triangulated to the fuse for lateral support.
I'm interested in your observation as to the weakness of Electric power.please elaborate on this.
I have a built in advantage as my fuse is composite shell and I can insert reinforcement at critical areas while vacuum bagging.
Please elaborate on the weakness of electric power and your observations.
Were you able to see photo of horn install on SV22 TA
The Yatsenko props are stiffer at the tips,In my observation from actual use they make less noise.
Do you think that if gas models were as quiet as electric that we would hear the same prop noises?
With the pusher prop I hear more prop noise on outside maneuvers then switch to tractor and the prop noise switches to inside maneuvers.
Jose Modesto

Yes I think if IC engines were quiet you could hear the prop. I have felt, for some time now, that the biggest flaw in the electric sett up was the thin flimsy APC props. Because I fly some RC and know quite a few guys that use both big and small electric setups I am very aware of how much power is available. Just look at IC, we use very stiff carbon props to get the desired affect. I recently switched from Bolly props to Mejzlick, the Mejzlick props are much stiffer than the Bollys. I found that when I changed, my plane tracked better in maneuvers and pulled through hard corners better. Now, I do feel like the Bolly is a better wind prop for the same reason, it flexes more thus flattenting out under heavy load. This made it wind up less in the wind. The benefits of the Mejzlick outweigh the Bolly in my opinion.
I can see vibration and hear the prop noise you are talking about when you go through hard corners with the APC props. I think that this is a big disadvantage for the electric motors or IC if you used a similar prop. If there is any place that you do not want to give up power it's in the corners.

Derek

jose modesto · « **Reply #13 on:** January 10, 2012, 09:32:33 AM »

Derek my challenge is the new APC 13x4.5 pusher is stiffer and is less noisy but model performs better with the thin floppy blades. This is contradictory to our shared logic on stiff being better.
Since electrics have 14 power pulses per revolution and IC has one strong violent jolt,this may be an area to look at.
I will mount a tune pipe 3 blade Bolly and mezlik and get a comparison.
My Brian Eather carbon fiber 2blade copy of the Yatsenko may be a better alternative.
Will keep you posted.
Jose Modesto

Derek Barry · « **Reply #14 on:** January 10, 2012, 10:59:48 AM »

Quote from: jose modesto on January 10, 2012, 09:32:33 AM

Derek my challenge is the new APC 13x4.5 pusher is stiffer and is less noisy but model performs better with the thin floppy blades. This is contradictory to our shared logic on stiff being better.
Since electrics have 14 power pulses per revolution and IC has one strong violent jolt,this may be an area to look at.
I will mount a tune pipe 3 blade Bolly and mezlik and get a comparison.
My Brian Eather carbon fiber 2blade copy of the Yatsenko may be a better alternative.
Will keep you posted.
Jose Modesto

WOW that is interesting. I would put money on the stiff prop but I guess I would lose this one. I see you are running relatively low pitch, in comparison to the stock setup of a shark. How do the electrics handle higher pitch and lower rpm? This could have some affect on the way the plane flies.

I never thought about the "power pulses" either. Interesting stuff, keep us posted.

Derek

tom hampshire · « **Reply #15 on:** January 10, 2012, 11:16:19 AM »

Indoor flyers build props that twist so as to increase pitch with higher torque, to take advantage of the power burst from the rubber strand at the start of a run. Hence, I wonder whether the APC plastic props gain or lose pitch with higher torque. If the CP of each blade is at 25% chord, than the thrust (lift) vector might well tend to twist each blade in the direction of more pitch. It would take a strobe light camera just to test it on the bench. In the air I dunno how it could be instrumented.

Dennis Adamisin · « **Reply #16 on:** January 10, 2012, 01:06:31 PM »

Quote from: tom hampshire on January 10, 2012, 11:16:19 AM

Indoor flyers build props that twist so as to increase pitch with higher torque, to take advantage of the power burst from the rubber strand at the start of a run. Hence, I wonder whether the APC plastic props gain or lose pitch with higher torque. If the CP of each blade is at 25% chord, than the thrust (lift) vector might well tend to twist each blade in the direction of more pitch. It would take a strobe light camera just to test it on the bench. In the air I dunno how it could be instrumented.

Tom:
As you know APC has redesigned all of their electric props with thicker/much stiffer blades. In every case I have heard the thick props act like they have less pitch; curent draw is down but they must run faster (800-1000 RPM) to achieve the same airspeed as the prior thin blade designs. For example, the thick blade 13x5.5 runs at about the same RPM as the thin blade 13x4.5. Thus your obervation about the APC blade flex ADDING pitch sounds spot-on.

Another supposition of the flexi-prop is that the flexing likely manifests itself as prop noise. Again, many of the folks who replaced the thin blade 13x4.5 with the thick blade 13x5.5 (at similar RPM) report that it runs noticably quieter.

Kinda the opposite of those old yellow Tornado nylon props that always seemed to flatten with RPM! They also seemed noiser even on an unmuffled McCoy 35RH on a profile...

Derek Barry · « **Reply #17 on:** January 10, 2012, 01:28:10 PM »

Quote from: Dennis Adamisin on January 10, 2012, 01:06:31 PM

Tom:
As you know APC has redesigned all of their electric props with thicker/much stiffer blades. In every case I have heard the thick props act like they have less pitch; curent draw is down but they must run faster (800-1000 RPM) to achieve the same airspeed as the prior thin blade designs. For example, the thick blade 13x5.5 runs at about the same RPM as the thin blade 13x4.5. Thus your obervation about the APC blade flex ADDING pitch sounds spot-on.

Another supposition of the flexi-prop is that the flexing likely manifests itself as prop noise. Again, many of the folks who replaced the thin blade 13x4.5 with the thick blade 13x5.5 (at similar RPM) report that it runs noticably quieter.

Kinda the opposite of those old yellow Tornado nylon props that always seemed to flatten with RPM! They also seemed noiser even on an unmuffled McCoy 35RH on a profile...

Hey Dennis,

Interesting stuff. Has anyone (I am sure they have) put these props on a pitch gauge to check the pitch?

Howard Rush · « **Reply #18 on:** January 10, 2012, 02:01:33 PM »

Quote from: Derek Barry on January 10, 2012, 01:28:10 PM

Has anyone (I am sure they have) put these props on a pitch gauge to check the pitch?

You have to look in a mirror to use a regular prop gauge with these props. Hope this helps.

Dennis Adamisin · « **Reply #19 on:** January 10, 2012, 03:18:39 PM »

Quote from: Derek Barry on January 10, 2012, 01:28:10 PM

Hey Dennis,

Interesting stuff. Has anyone (I am sure they have) put these props on a pitch gauge to check the pitch?

Yes!

I have some Excel plots of pitch distribution somewhere, I'll see if I can find them and post them in a "Stunt Hanger Friendly" format. There is a small cuff (looks like a trailing edge flap) along the inner 50% of the blade that wreaks some havoc on measuresments but pitch is normally pretty close to advertised.

Many folks have been removing the cuff - usually reduces the current load but you might have to add 100 RPM or so to get your lap time back. however it shifts the loading out farther on the blade (make sense?) so it can still be a small efficiency gain (small reduction in mah used per flight).

When ordering the new/custom props from APC I have stopped asking for pitch, rather I ask for diameter and operating RPM (i.e, ask for a 12" prop that will deliver 55MPH @ 8400 RPM) and they have been pretty good at hitting the target.

Dean Pappas · « **Reply #20 on:** January 11, 2012, 10:09:51 AM »

Hi Gang,
Of course, a very thin airfoiled, almost weightless and super stiff prop would be the best.
As soon as we figure that out, we'll have it made.
Yes, the prop noise is often heard above the engine: all it takes is for the tips to go transonic.
This occurs (depending on prop design) when the product of RPM and diameter (RPM and inches) gets bigger than 130,000.
For certain 140,000 is going to have prop tip howl.

Dean P.

Derek Barry · « **Reply #21 on:** January 11, 2012, 10:26:54 AM »

Quote from: Howard Rush on January 10, 2012, 02:01:33 PM

You have to look in a mirror to use a regular prop gauge with these props. Hope this helps.

Yep. Thanks Howard

Dean Pappas · « **Reply #22 on:** January 12, 2012, 08:59:33 PM »

Howard,
With that signature line, I'm guessing that you really like Tom Watz' song "Step Right Up", eh?

Dean

Lauri Malila · « **Reply #23 on:** January 13, 2012, 11:19:49 AM »

Hi.

If asked nicely, Yuriy can also make a pusher version of the 14,2x6. But I use them in IC

And remember that also these props can be tweaked with heat.
L