First Vess Props are here!

[RobertV]

Hello Everyone,

I wanted to personally annouce that the first Vess Propellers are now ready for sale. That's right, the long wait is over and I have really appreciated your patience! I've been really busy on all of this so I haven't been able to respond to all questions posed here. But you will soon be able to get all the information you are after since my website is expected to launch early next week, www.vessaero.com.

If you have read my previous comments in some of the other threads on the subject, you already know that the first sizes to become available are the 27-inch series that are optimized for 100cc class aircraft and the 32-inch series for 150cc class aircraft. I am working on many other sizes that will be released as soon as possible, but they won't come until I can be sure that they meet the standards set by these first ones.

Also, I announced in a previous thread that Desert Aircraft will serve as a distribution and customer service partner. And what better way is there to launch this new product line than with the guys that have the best customer support in the industry. So I'm happy to say that Desert Aircraft has been completely stocked with these inital sizes and is ready to take your order right now! So pick up the phone and give them a call. And they'll have them for inspection and purchase in their booth at the Toledo Expo next week, too. I'll even be there to meet you and answer your questions. Be sure to stop by!

And don't forget that Biff will be carrying a batch to many of the bigger events in the country so that you can "fly before you buy". I hope to be at a few of them, too. I know for sure that I won't miss Joe Nall.

I trust you will find that these props offer a marked perfomance increase and look forward to hearing your personal flight reports!

Best Regards,

Robert Vess
Vess Propellers

[why_fly_high]

Sounds great! How much will they be?

Dan

[JeeUm]

Good news. Just ordered mine through Desert and they'll be here next week. I got the 27x10.5 "A", and the 27x11"B". Both are $53.

[SMOKEY]

Whats the performance difference between "A" and "B"? What type of flying will "A" or "B" be suited for? Very interesed in trying them. Anybody have RPM reading for a DA100 with stock mufflers at sea level?

Smokey

[RobertV]

Hey Guys,

Since my website is not going to be up for a few more days and these type of questions are already coming up, I'm going to post some material that I hope will help clear up things a bit. Sorry for the length of this!

Robert Vess
Vess Propellers

Understanding Vess Propellers

by Robert Vess

The unique shape, design, and size designations of the Vess Propellers did not come about by accident. They are the result of many months of computation, prototyping, and testing. And instead of simply recreating another version of existing designs or following conventional practice, this project began from a “clean sheet of paper” and proceeded in a direction that was guided by formal engineering analysis. The result is a prop design that truly sets a new standard for performance, efficiency, and noise reduction.

The introduction of anything unconventional is sure to draw questions since it is not supported by conventional thinking. It’s the nature of being different. Vess Propellers certainly fall into this category and thus a little simple education is warranted. So, here are some replies to typical questions that you may have or expect to hear.

Q. What was done differently during the design of these props?
A. On any aircraft, the airframe, engine, and propeller combination represent a system in which each component affects the other two. The objectives of the design of Vess Props were to document this relationship for typical classes of giant scale aircraft (Ex. 100cc engine on a 33-35% airframe) and to understand what the props require to operate efficiently in those specific applications. Then computer tools were applied to design efficient props that would absorb the “real” engine power at “real” flight speeds and at RPM’s that avoid sonic tip speeds, while producing maximum thrust for a given amount of power.

Q. Why are these props shaped like this?
A. Instead of just picking a shape and using a constant pitch along the blade, the shape of Vess Props were designed in an integrated manner to work well in their intended applications as noted above. This means that the distribution of chord, thickness, blade angle, and airfoil were optimized at each station along the blade using advanced theories and computer algorithms. This produced benefits in thrust and efficiency over constant and linear pitched props. The blade sweep also has a favorable influence on the noise generated by the prop.

Q. Since the pitch is not constant, how do you know what it is?
A. It is not important to know what the pitch values are. It is only important to know how one prop relates to another so that you can select the proper one.The diameter of the prop is chosen to put you into a typical “class” of aircraft/engine. Remember, our extensive analysis and testing has optimized a blade shape and pitch distribution to work well for that combination. And linear pitch designations don’t apply to it! Instead, we have employed a simple alphabetic designation for pitch. And we have also created a prop series for each diameter that will allow you to adjust to your particular setup.

Q. So how does this alphabetic pitch designation work?
A. It’s as easy as A-B-C! The “baseline” prop that most people will start with in a particular diameter series is designated with a “B” pitch (remember – “B” is for Baseline). So, if you have a typical 100c powered 33-35% aerobatic airplane, you will start with a “27B” prop. It will most likely give you the tremendous vertical performance, great acceleration, and low noise that it was designed to deliver. But all engines, airplanes, and even weather conditions are not alike. So, there may be a better choice for your case. If you have an aircraft that is heavier, has more drag, or is larger than a typical 33-35% aerobatic model or has less horsepower (either due to less displacement, higher field elevation, or higher air temperature), you may need to go down to a “27A”. Conversely, if your airplane is lighter, has less drag, or is smaller than a typical 33-35% aerobatic model or has more horsepower (due to more displacement, lower field elevation, or lower air temperature), you may can use a “27C” to properly absorb the power and keep the propeller quiet. Remember, the prop, engine, and airframe directly interact and affect each other so you need to think about that when choosing your prop. And this series concept allows you maintain high performance and low noise amidst changing weather conditions across a flying season.

Q. How quiet will my plane be with a Vess Prop?
A. Noise is driven by the loudest component is a system. If you have a loud muffler, you will not realize the full potential of using a quieter propeller. But it will still help! Recall that Vess Props were optimized to absorb the power of particular classes of engines at RPM’s below which the tips reach sonic conditions. In almost every case that we have tested over the past year, the Vess Prop did not unload to the point of producing sonic tip noise. In virtually all cases, the in-flight noise was dominated by the exhaust sound.

And recent sound testing by the organizers of the “Don Lowe Masters” competition have shown the true potential of Vess Propellers for controlling noise. A 43 pound, 42% Hanger 9 Ultimate fitted with a DA150 engine and canister mufflers measured 93db at 25 feet with a Vess 32D prop! This was actually slightly less than a popular carbon 3-blade on the same airplane. And the in flight performance of the Vess prop was astonishingly better! Also, 40% Carden Extra 300 with DA150 and Johnson-type mufflers measured 98db with the same Vess Prop and also showed fantastic performance in the air. You don’t need to fly a loud airplane…even with stock mufflers.

Q. What should my Vess Prop tach on the ground?
A. Don’t waste your time measuring ground RPM unless you are attempting to somehow quantify relative loads on the engine. Vess Props will usually turn less on the ground and in the air. It’s part of the design philosophy of properly loading the engine under real flight conditions. The benefit comes from the thrust that is produced at that lower RPM. So judge these props against others through performance in the air. You will most likely be amazed!

[Texx]

I have been eagerly waiting your props to be releised! I will order mine tomorrow from DA!

Thanks for announcing it here on the Flying Giants Site first!!!

[Fudman]

any idea when the 50cc props will be out or how far are you in the process?

[YaKs are BeSt]

will you make any in carbon fiber or are wood easier to work with and fly better.

[RobertV]

Fudman,

The 50cc sizes are next in line and it will most likely be at least 6 weeks before they make it to market.

Yaks,

I would like to do composite props in the future but right now I have alot of things to accomplish in wood.

Robert

[Fudman]

Ill be waiting.

[Hinckley Bill]

Rob,

Wow...and I thought picking up my new trailer on the way to Toledo was going to be the highlight of my trip...

I'll definitely be calling DA on Monday for a couple of props....got a H-9 Ultimate that could use "a little" more power and a DPM 40% 540 that should also benefit.

Look forward to meeting you at Toledo!

Bill

aka "Hinckley Bill"

[Biff]

Guys,,,Robert himself Biffcasted!!! Launching shortly,,hear it from the super duper genius himself!

[xtremeRCpilot]

Hey Robert, What would you recommend for a ZDZ 80 rv for 3d/freestyle flying and when will they be available(approximately) cant wait to try one out...

[madmax]

Hi guys, well that was a fun Saturday evening. This thread has been moderated, please keep it respectful to everyone involved.

Robert - Congrats on your launch!!! Glad to see great new products hitting the market!

MD

[WOODisGOOD]

I have a 27 B coming this week. I will get some numbers on it this weekend and compare it to the 27 x10 Mejlik that I have been flying. Cant wait to try it out.