Ultralight propeller comparison, comparing different ultralight aircraft propellers, testing different ultralight propellers.

Comparing different ultralight aircraft propellers.

We have since this test, inverted the B-model gear box on the Rotax engines only, and have made this the new standard.

While the prop diameters have changed with this new set-up, we still feel that info still fairly reflects the current performance figures that we are now experiencing with the new diameters and pitch of the props being used. This original prop shoot-out was conducted in the early spring of 2001.

Rotax 447 / 503 Inverted B- Model Gear Box
Retro-Fit for Existing Up-Right Mount.
5/7/02
PROPS...Props...props...
The "propeller" that big hunk of wood, plastic, or some other new age material, has at least one blade and up to as many as six. Is probably one of the most debated subjects in any type of aviation. With the numerous theories, speculations and "opinions" ( everyone has one of these) that surrounds the propeller. Without it we would just sit there and listen to our engine make noise and wish we were up there in the air with the birds. "Hey they don't use props".....smart design".

Unfortunately we simply can't flap our wings to get airborne so we must rely on our prop to provide the proper thrust to achieve flight. We want them to be powerful, smooth, reliable, and hopefully inexpensive. While flying our Aerolite prior to Sun-n-Fun this year we decided to revisit the use of the 3 and 4 blade Ultra-Props produced by Competition Aircraft. This actually was the prop/props that we originally used on our first few prototypes in the mid 90's. Well after bolting it to the 2-SI F460 and immediately I was refreshed on our smooth running this prop is and the performance was excellent during flight. So it was decided to leave it on and use this prop for the show.  

"Now"... before we get too excited here "remember" usually everything in aviation is a compromise. So what we did was to use both the 2-SI F-460 2.5:1 belt drive and the Rotax 447 w/ B box, dig out our props, hook-up a pull scale and get some hard facts.  

The prop dyno consisted of an Aerolite-103 powered either with the 2-SI F460 or the Rotax-447 and was hooked up to this scale, on a level surface and my butt in the seat. This allowed us to keep all things the same. Simply changing to a bigger butt in the seat changed readings as much as 30lbs in the thrust department. So what I will try to do is break down each engine combination along with the difference in thrust only between props and not the actual thrust readings. "And why" is because, I can see someone performing the same test that we did and either they have a bigger butt or smaller one than mine, their plane is either lighter or heavier than what we tested ..... and then the worries, or false claims, opinions and debates begin. We are simply to busy to get hammered with either e-mails or calls of those wanting to debate this issue. The info here will allow you to compare, verify, possibly consider a change to your set-up and should be used as a valuable source of info. We only want what is the best for our Aerolite and those that fly it.  

Rotax 447

The 4-blade Ultra-Prop. Great performance and real smooooth.

Power Fin 2-blade offers durability and good thrust.

 2SI/F-430/460

• All props tested are recommended and authorized for use on the Aerolite-103.
  

• It was also noted that it takes a strong 35+lbs. of thrust to experience or feel a performance difference during hard acceleration and very steep climb angles. All of these props fall short of this.
  

• It to seemed that when using the 3 & 4 blade Ultra-Prop that while they seem to allow the Aerolite to slightly pop up off the ground sooner,  they would however washout or stall (the blades) sooner at very steep climb angles. I'm talking the kind were you are touching the tail as you rotate...you should not be flying this way anyhow. However they will climb out just as well as the other tested props under normal operation and flight of your Aerolite.
  

• While adjusting the pitch on the Power-Fin , "while much easier than the old design". It seemed to take about 2 - 3 tries and being very careful while you torque the prop bolts and following a torque pattern to keep both blades even.

OK, So what does it all mean?
Well that depends on what it is you want, more static thrust, smoothness, top speed, better fuel burn, durability, cost friendly, cool looking, simplicity or how about all the above. That would be the miracle prop! Unfortunately we can't give you this but you can by using the chart and with a little compromising determine what is best for you and your Aerolite. If you are beginner and don't have access to anyone experienced then stay with the simplicity of the wood prop that comes standard with the Aerolite. Once you gain some experience, you than can play with some of the pitch adjustable props. Also if your a big pilot or your plane is heavy than you should probably put up with a little vibration and use the 2-blade prop. Best static thrust is achieved with a 2-blade prop and as large of diameter that the engine can turn and the air frame allows. It seems that going to 3 or more blades definitely is a smoother combination on the Aerolite, but this will cost bigger bucks$$. As far as bang for the buck and performance the wood prop is still the better choice only sacrificing in the smoothness department. This will still be what we will continue to offer as the standard prop for the Aerolite-103.

"Now" if the other half would give me a little more allowance $$ each week my pick for the Rotax would probably be ...hummmm...either the 3-blade Power Fin, or 4-blade Ultra-Prop. For the 2SI-F460 I would "definitely" go with the 3-blade Ultra-Prop. You got to love the fuel burn during the cruise along with a higher top speed that the 2SI and Ultra-Prop have to offer. The combination of the belt drive and this prop was so smooth. I had to keep looking back to verify I still had my prop, it was so smooth in the air during flight. I simply loved this combo while flying in Florida and so did everyone else that flew it. But.....then, if I want to show off, hotrod it, or perform demo flights then I would still choose the good old Tennessee wood prop, compromises, compromises...hmmmm.