Joe McBride

My Feedback: (12)

I got a sample prop from Robert and bolted the 27x10 Vess up on the DA 100. I'll take her out this weekend and see how she does against a standard prop.

I've got a buddy who has the same plane with a classically shaped prop so we should be able to do some drag races (straight line and hover start!), to get a flight comparison.

I'll post results on Monday.

SJ

Joe McBride

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Looks like I need to clean the bugs off that cowl!

mu2driver

My Feedback: (15)

Crazy simitar shape...looking fwd to hear how you like it..do they make bigger sizes for our 150's ?Also whats the cost for one ? Link to a site ?

Joe McBride

My Feedback: (12)

I'm expecting Robert Vess to chime in anytime now to answer your questions with the authority that only he can.

Here's a couple shots to compare it to a conventional 27x10.

mu2driver

My Feedback: (15)

Keep us posted on the performance gain, just like boats a prop is the single best performance piece you can add...

ThrottleJockey

My Feedback: (2)

Than thing looks crazy! Cant wait to so how it works out! Sure would be a easy way to add power.

CptCliffhanger

My Feedback: (6)

Sweet! You've got so many flights on the plane with the NX, you should be able to tell the deffernces right odd the bat!! I'm curious to see how you like it freestyle. If it does what they say it does, you should love it!.. Now for a full precision flight review, I'm the only one who ever flew a full IMAC routine on that plane with your old prop. You're gonna need me to test that thing out for IMAC performence! :-)
reminds me on an APC!

SEG

no stephan he did the harrier basic routine haha

Joe McBride

My Feedback: (12)

Thats right SEG. After hours at the next contest we'll have a 3D sequence event. The entire sequence must be flown with the wing stalled.

You zero any manuever that is not STALLED!

sillyness

My Feedback: (25)

Any word here?

rcblimppro

When are these going to be available. I am in need of a new 32X10.

Shawn

Joe McBride

My Feedback: (12)

My report to Robert Vess:

Robert,

I tested the 27x10 Vess on a DA 100 and a QQ 102” Yak. Conditions: 460’asl, 67deg F, 66% Humidity .

Here are my observations (I would have liked to have had more props to compare):
V7 = Vess 27x10
N7= NX 27x10
N8=NX 28x10

RPM: V 5950, N7 6600, N8 NA

Noise: V7 was very quiet compared to the N7, and slightly quieter than the N8.

Static thrust: V7 seemed to have more thrust at lower throttle settings than the other prop. In torque rolls/hover the V7 was more linear (smoother) with throttle inputs, than the N7.
The V7 took longer to spool, but was less “jerky” than the lighter N7. Its throttle up time was similar to the N8, maybe slightly slower.

High Speed: On full throttle long upline pulls (or top of big loop) the plane carried less speed with the V7 than the N7 and performed similar to the N8.

Summary: The Vess made Hover smoother with somewhat of a flywheel feeling over the lighter but jerkier feel of the N7. For precision the V7 would be an excellent choice especially where noise is critical. For Freestyle I prefer a quicker spooling prop and higher top end speed on the plane than the V7 provided. Overall the V7 loaded the motor more than I would like. The fact that the density altitude was above sea level, may have contributed to that factor. I would be very curious as to how a V 26x10 would perform and if it could give the higher speed of the N7 without the noise.

Thanks for pushing the envelope on prop development!

“Smokin” Joe McBride


And his reply:

Joe,

This is some excellent feedback and I especially like the comparisons with the existing props. Thanks, it was a real Cirkus style test!

As I mentioned to you previously, my props are actually not linearly or constant pitched like virtually everything else on the market. They have a twist distribution that is optimized to produce the most thrust for a given load. It’s a major part of the design philosophy whereby I am trying to avoid excessive prop unloading (which is a major source of noise) while still producing increased thrust. So, although the prop I gave you was marked “27x10”, that was only there so that my testers would utilize them in applications where they would normally use that size prop. The prop I sent you is actually on the "highest load" end of a three-prop 27" diameter series. It seems to be matched very well to relatively clean 33% Edge and Extra style airplanes with 100cc motors from testing done on my side of the US. But, as I mentioned , it could be a little too much load on a higher drag, radial style (and slightly larger at 35%) airplane like the QQ Yak (I have actually just received a 102" Yak from Quique and will also be testing some props on it soon). If you are willing to trade "some" noise potential for additional RPM, the other two lower-pitched versions of that 27" diameter might be more in line with what you are looking for in your particular 3D application. I will also have 26 inch versions in the future as you mention.


The Cirkus crowd might like to know that I will be introducing my 100cc and 150cc class props to the market in mid March. I will sell them via an internet site that should be launched in early March (www.vessaero.com) and will also have a full dealer program. Also, Dave Johnson at Desert Aircraft and his staff will be selling and distributing them in a similar capacity but will also provide the same value-added support that customers of his fantastic engines have certainly appreciated.

Thanks again for your input and I'll be sure to send you other props to try as they become available. Like I said, I value this type of information.

Keep up the good work with the site!

Robert Vess
Vess Propellers

randy racer

My Feedback: (3)

thanks joe, thats great info. i'm wanting to try one of these on a 35 am yak so i may need a little less pitch. please keep the info coming.

randy

PLANEBENDER

My Feedback: (3)

Thanks for all of your hard work Joe, really helps out. Can't wait to try out a 32X10 version for 3-D. Dave

jsnipes

My Feedback: (3)

I met Robert out at the field today with my new 102" QQ Yak. It has a DA100 with MTW cannister mufflers. I started out with a Mejzlik 27x10 for the first two flights. Uplines were good as expected and the prop was quiet. I then bolted on the new Vess 27"A" for the next flight. The "A" is the least aggressive pitch combination in the 27" line (vs the "C" version that Joe reviewed above). The "A" is geared toward heavier or more draggier planes in the 33-35% range or for higher density altitudes. (Robert can jump in and correct me if I am mis-stating this). Also, we're in Raleigh NC, so pretty low density altitude ... it was ~ 60F today.

Though not scientific, I noticed two things. First, the acceleration out of a hover and the ability of the plane to carry speed on uplines was greatly improved vs the Mejzlik. Not that the Mejzlik was aweful, but you could easily tell that the vertical performance was improved with the Vess prop. From accelerating out of a hover I could do two deep snaps and then continue vertical rolls with authority.

Secondly, the Vess prop was slightly louder than the Mejzlik in my opinion. It was not 'ripping' or even close, but it was slightly louder. From talking with Robert, the whole thing is a balance of ripping the prop due its unloading vs pull. Since the Yaks are more draggy than Extras, etc the prop unloads less so the "A" pitch profile works better on it than the "C" version that Joe and others tried. I guess it being slightly louder but better pull than the Mejzlik on the Yak is showing that it's a better combination on the Yak than the "C" ... at least for our density altitude.

Downline braking was similar on both props ... I couldn't tell much difference.

Anyway, Robert can chime in with his opinion as he had his turn at the sticks with both props. Once he gets his Yak flying I'm sure he'll be taking some good engr data that he can share with us all comparing performance vs different props.

A picture of the latest version is attached ...

JS