Being an aviation engineer and professional light aircraft designer, I use and compare different propeller brands from 1987 year.
I used composite, wooden, plastic and metal; constant pitch, ground and in-flight adjustable;
constant and variable RPM propellers not only for aircrafts but also for hovercrafts, airboats etc. Working in Europe and North America, I think
I tried all propeller brands.
Many amateur builders and pilots underestimate the importance of the propeller for their crafts. If they are not happy with their aircraft
performances, noise or vibration, they think about changing the engine for more powerful one, redesigning the motormount, muffler etc. But the problem can
be fixed much easier very often. I always advise
to start thinking "from the prop". Is it a really efficient one? Is it well matched to your engine and craft? Is it in a good shape, well balanced?
My experience - a good correctly chosen and installed prop can fix such problems in most cases. To change the prop is much easier, faster and cheaper than changing the engine,
but the effect can be the same or even better.
I don't use anything but KOOLprop now. My opinion - this is
just the best propeller for most prop driven craft regarding its quality, efficiency and price. Most of my clients using KOOL have the same feeling.
If you build a new aircraft, airboat or hovercraft and not sure which prop you need; if you want more thrust, shorter takeoff, higher cruise speed,
lower gas consumption; if you are tired of the noise and vibration - try new KOOLprop. I promise, you won't be disappointed!
Ground adjustable propellers
KOOLprop is designed and made for different airscrew driven vehicles: Experimental, Ultralight and Light Sport airplanes, trikes, airboats, hovercrafts,
autogyros, power parachutes, paragliders etc. All blade models are designed using computer technologies, then tested in a wind tunnel and in flight
+ passed special destructive tests. There are 26 different prop blade models for different applications, right and left hand rotation,
pusher and tractor, straight and scimitar shape, from 47 to 78 diameter. You can use them with a lot of engines from small Simonini PPG 15-18HP to
powerful Rotax 914 and Subaru-Suzuki-Honda autoconversions up to 260HP. Special reinforced blades can be ordered.
Finish is excellent black gelcoat, often with white tips. Black blades are preferable for tractor planes - better visibility through the prop.
The white tips make the running prop ends more visible to increase safety. White
and 2 color (one side white, another one black) blades are available as a special order.
I can compare KOOLprop with Kievprop I was flying and selling before. Koolprop has exactly the same hub design, CNC machined from aviation aluminum allow and anodised. Most blade models have the same root shape as popular Kiev, KOOL, Aerolux etc. models and can be used as their direct replacement,
You can use your old Kievprop hub and spinner with Kool blades. There are some points making Kool preferable for me. They are both hand-made with highest accuracy but KOOL prop
is made with carbon fibre + fiberglass composite instead of only fiberglass-made Kievprop. Koolprop blade is more rigid, it helps reducing idle wobbling and slipstream interference
vibrations. KOOLprop finish is epoxy gelcoat, not paint like Kiev, so KOOL surface is harder and smoother, more difficult to scratch. As Kiev, Kool has integrated strong leading
edge protection, but it is made with thick riveted Stainless Steel or Ultra High Density Polyurethane, not copper. This protection is stronger than Kiev LE. It has very good abrasion
resistance and makes KOOL preferable for Amphibian and Float planes as well as STOL and Bush planes flying from unprepared runways -
ideal protection against water splashes, tall grass, dirt, tiny rocks etc. + Stainless Steel looks always shiny. Most blade models have the same root shape as popular Kiev, Aerolux
and can be used as their direct replacement.
We sell and use KOOLprops for all trikes and powerplants made by Air Trike Enterprises from 2006.
All KOOLprop users mentioned that KOOL is more smooth, silent, and provided better performances than their previous propellers.
To see pictures and read feedback Emails from pilots using KOOL props CLICK HERE.
Spare blades are available. If my customer brakes one, two or all blades, he sends me the type and serial # of the blade (moment of inertia) printed on its root, and Air Trikes supplies
spare blades already balanced and matched to his blades. Spare blade orders are always highest priority.
Set of replacement blades for Kievprop and Aerolux hubs. Fast delivery, best performances, SALE PRICE - CLICK HERE!
Small diameter props are widely used for PPG, light PPC and airboats.
The prop hub system with aluminum plates and clamping blocks allows to change the prop diameter, make your custom prop. You can order as many sets (blade + clamping blocks) as you need
and make you own hub plates for up to 12 blades.
There are 3 types of Kool blades - classical straight, saber shape (similar to Kievprop, Aerolux etc.) and scimitar . Which type is better? No simple answer...
Straight, classical-style blade is able
to produce more static thrust with the same diameter. It can be important if you are restricted
in diameter, for example in case of PPC, PPG, airboat. Can be more efficient for low speed crafts, low prop RPM; preferable for planes with
low prop-ground clearance flying from unprepared fields.
Scimitar-style modern blades with "supersonic" tips are usually more efficient, especially for higher speed aircraft and high prop RPM engines. If you want maximal cruise efficiency, minimal level of
noise and vibration - this is your prop. But these blades are more complicated in production so a scimitar set of blades is about 100$ more expensive than the straight one.
Saber blades are easier to produce than scimitar ones but their aerodynamics and performances are close.
KOOL can be ordered with pure carbon fiber blades and spinner. These blades can be recommended for powerful engines,
they are lighter, but more strong and rigid than standard blades.
Video clip - Polyurethane Leading Edge blade crash test. As you can see, this leading edge protection is very effective.
Variable Pitch Propellers
In-flight adjustable or Variable Pitch Propeller (VPP) is intended for Experimental light and Ultralight aircraft, airboats, hovercrafts, snowmobiles etc.
The hub has a special mechanism allowing to change
the prop pitch on a running engine. It allows to keep maximal prop efficiency, thrust an fuel consumption for high airspeed range. Airplanes with VPP have shorter takeoff,
faster climbing, better fuel efficiency, higher maximal speed.
The prop can be made with reverse or feathering. Reverse (negative pitch) allows to move the craft backwards.
It can be useful for airboat, hovercraft, amphibian or float aircraft. Reverse can help to make a landing run shorter working as a powerful air brake.
Feathering is a useful
option in case of engine-off landing. A stopped feathered (around 90 degrees pitch) prop have much lower aerodynamic drag than a prop without this option or a free-wheeled prop.
The hub
has a special control rod going through a hollow gearbox/redrive shaft. It can be connected directly - mechanically or electrically (through a linear electric motor) with a
control lever/switch in the cockpit.
Short technical description of this prop is HERE.
2 video clips - Zenith 701 flying with VPP and pitch change are below:
New special saber shape blades with metal LE were designed for VPP in 2019.
The standard VPP hub is designed for Rotax 582-912S prop flange standard. It can be 2, 3, 4 and 6 blades. Knowing your engine power, reduction ratio, max. power RPM and craft speed range, we can calculate the prop
efficiency and propose the best propeller (diameter, number of blades etc) for your craft. SAE, custom made special extended hub or bolt circle diameter, or 5, 7, 8 and up to 12
blade hubcan be designed and fabricated following your specs. VPP can be ordered left and right hand rotation, pusher and tractor. A special 12" diameter spinner is an option.
Pictures of new blades, some custom designed and fabricated VPP below:
5 pictures of assembled and disassembled 6-blade hub and control mechanism. CNC machined hub halves from 2024T6 aviation grade aluminum, hard anodized.
High precision ball bearings are used for blade assemblies and pitch control mechanism.
Spinner
Spinner is strongly recommended for better performances and looking of tractor type airplanes. A pusher type craft looks more finished with it.
We have 2 sizes of carbon-fiberglass spinners: 8 diameter 9 length for the standard hub and 10.3" diameter 11.4 length which
can be used for both standard and large hubs and for Variable Pitch propellers. The spinner provided additional protection for VPP hub bearings from water and dust.
The weight of these spinners are around 500g (1lb) standard one and 650g (1.5LB) big one. They can be used not only with KOOLprop but with some other prop brands.
Koolprop specifications.
- Diameter 47"-78"
- Maximal blade width 5.9"
- Maximal speed of rotation 2800 RPM*
- Power of engine 18-260HP
- Stainless steel, Aluminum or Polyurethane integrated LE protection**
- Hub type "Rotax" 582/912 75mm (4" special order)
- Available in left and right hand rotation, for pushers and tractors.
- Life expectancy 1000+ hours
- Warranty against manufacturers defects 100 hours for 1 year***
* up to 3500 for several reinforced prop models
** Standard for all except 47"-49" PPC blades
*** up to 500 hours for 2 years for several prop models
ATTENTION! This propeller is not tested and recommended for Lycoming and Continental engines without torsional dampers. Some reinforced blades were tested and can be used for
VW, Jabiru and other direct drive engines.
Koolprop standard set included 2-3 blades, hub, all hardware, pitch protractor and soft blade covers. 4, 5, 6 blade props and custom made props with clamping block hubs are available too.
Assembling and installation instruction for this prop is HERE.
Order information
List of available propeller models - CLICK HERE. Koolprop has highest quality and very reasonably priced. We are always ready to help you with the best propeller choice. If you need a prop - call us
or better send E-mail with the following info: engine type, HP, max power RPM, reduction ratio, max possible prop diameter, rotation direction*,
type of your aircraft, cruise speed. We usually have most propeller models in stock and can send the same or next day after your payment.
*Right-hand propellers rotate clockwise to provide forward thrust. Left-hand propellers rotate counter-clockwise to provide forward thrust.
For spare blade order, send us the numbers on the blade root - blade model and serial number
Kool can be ordered with white or black carbon-fiberglass 8" and 10.3" spinner (strongly recommended for tractor applications) and different hub spacers.
4" (big) diam Rotax 912-914 shape hub can be ordered with reinforced KOOL blades.
6-blade prop. More than 3 blade propellers can be recommended if you have high power engine, slow rotating prop (high ratio gearbox) or prop diameter restriction.
Small left hand 49" propeller for light engines PPG, soaring trikes, motogliders. Can be 2-blade as well.
White propellers. Opposite side can be ordered black for better visibility through the prop (tractor planes). Different KOOL hubs, extensions etc.
