Mike,
The 64 inch prop is the blade length ideal for all versions of the 912ULS a
nd 914 equipped on the Europa Classic/XS/Mono/Trigear. It has the recommen
ded ground clearance for normal operations for the mono and trigear. Prope
ller manufacturers know the max length for each of their blades to meet the
Rotax moment of inertia, bolt pattern and other factors. I=92ve placed a
64 inch wide chord Warp on a 80HP Rotax and it just wouldn=92t turn it up t
o speed and top end cruise suffered. So max length is based on engine torq
ue.
Notes:
Warp Drive is comfortable with the Wide Chord (Standard) blade on high spee
d aircraft from 64 to 67 inches. I=92ve seen guys with 70 inch two blade W
arp Drive props on a Kitfox with a 912UL 80HP engine and the blade pitch at
the tip is flat.
Each propeller manufacturer will have recommended lengths for each of the a
ircraft / engine combinations. Airmaster is one of the few to actually pri
nt the lengths on their website by aircraft type and powerplant.
The 64 inch Warp/Sensenich/Whirlwind is what all of us put on the Europa an
d is the only length we recommend for the Europa 912ULS/914. The speed dec
rease at cruise is only a knot slower for the 64 inch and the ground cleara
nce is in the ideal range.
In the paper I wrote on What propeller blade length and hub was ideal for t
he Rotax engines, I commented that with most propellers of a 16 to22 degree
s of root to tip twist the length and pitch of the prop was calculated for
lengths from 64 inches out to 75. For fast airplanes (like the Europa) not
hing good happens after 67 to 68 inches. Inertia goes up (Warp Drive blade
s have high inertia) and lighter wood and composite props can be longer, bu
t at a speed penalty so I set the and had many prop builders hate me for re
commending =93Nothing good happens after 68 inches on a constant speed prop
on a Rotax engine in my opinion.=94 Sure, one can thin the tip way down o
r sweep it and get another inch per blade, but generally speaking 67 with a
warp, 68-70 with a Whirlwind and some Sensenich with the highly swept tips
(scimitar shape) rather than the round or square tips.
The definition of ideal prop length I have in my files for many other aircr
aft are:
1. Ground clearance. There must be a clearance of at least seven inches
(for each airplane with nose wheel landing gear) or nine inches (for each a
irplane with tail wheel landing gear) between each propeller and the ground
with the landing gear statically deflected and in the level, normal takeof
f, or taxing attitude, whichever is most critical. In addition, for each ai
rplane with conventional landing gear struts using fluid or mechanical mean
s for absorbing landing shocks, there must be positive clearance between th
e propeller and the ground in the level takeoff attitude with the critical
tire completely deflated and the corresponding landing gear strut bottomed.
Positive clearance for airplanes using leaf spring struts is shown with a
deflection corresponding to 1.5 g.
In the mono, the rubber block has a slant in it which when compressed stops
the gear deflection and will allow the mono in level flight attitude to me
et this 7 inch propeller clearance.
Best Regards,
Bud Yerly
-----Original Message-----
From: owner-europa-list-server@matronics.com <owner-europa-list-server@matr
onics.com> On Behalf Of Mike
Sent: Wednesday, December 29, 2021 5:21 AM
Subject: RE: Europa-List: Re: Propeller Sizing
umba.co.uk>>
Thanks Bud for your usual excellent reply.
I have been in contact with Dirk who has indeed suggested a replacement
blade of 64" and been most helpful but the issue remains, can I fit a 64" t
o
a classic mono. The LAA have provided me with a spreadsheet of calculations
to determine prop tip clearance at Max AUW which I will carry out but they
were unable to find out easily if any other classics were operating with a
64" prop so this is why I asked the community if anyone was operating with
one.
Thanks for the pointer to your website I will certainly have a look.
Thanks
Mike
-----Original Message-----
From: owner-europa-list-server@matronics.com<mailto:owner-europa-list-serve
r@matronics.com>
[mailto:owner-europa-list-server@matronics.com] On Behalf Of
budyerly@msn.com<mailto:budyerly@msn.com>
Sent: 28 December 2021 16:44
Subject: Europa-List: Re: Propeller Sizing
m>" <budyerly@msn.com<mailto:budyerly@msn.com>>
Mike,
My website has how to select a prop for your Rotax.
The 62 inch Warp Drive Taper blade is fine for most 80HP Rotax powerplants.
The Rotax 912ULS 100HP has significantly more torque and the 62 inch tapere
d
blade is not very efficient. My US folks were very disapointed with trying
to use this short tapered blade on the 912ULS in both the Airmaster and the
fixed pitch versions.
The blade angle will be quite high and takeoff will be shortened, climb wil
l
be less and the cruise will be about 5 knots slower. The 80HP Rotax won't
spin a wide chord 64 inch without lugging the engine down. There is just
not enough torque. The tip at takeoff is not able to bite for good
performance.
The LAA recommendations is for the Warp Drive Standard (wide chord) blade o
f
64 inch for the Europa (which limits the length for the airframe to 64
inches) and was the standard Airmaster for a number of years. The 100HP
Rotax has the higher torque and can spin the wider and longer props with
authority.
Also available for the cost of a blade change is the Sensenich high speed
blades. Whirlwind has a blade but due to Covid lockdowns in California lea
d
time is many months. Sensenich and Warp Drive are made in free States so
production and labor issues are not a major problem for delivery at this
time. Airmaster will build you up a set of blades and ferrules ready to
mount. It will cost you but it is worth it.
Contact: Dirk Oyen
Oyen CTR (Europe Sales and Service)
Hemelrijk 61
Heusen-Zolder
Limburg 3550
Belgium
E: dirk.oyen1@telenet.be<mailto:dirk.oyen1@telenet.be>
M: +32 477 25 80 28
Website: https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2F
www.propellor.com%2F&data=04%7C01%7C%7C83afb0f859684abcf48c08d9cab586
f8%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637763703272349596%7CUnknow
n%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI
6Mn0%3D%7C3000&sdata=iVTZnINjOqTFY6wf%2FrliZa6wbO3tsIgmwOj%2BNXncOEg%
3D&reserved=0 your European Airmaster Dealer. He has the
experience you will need to draw on in the UK (See the Airmaster Contacts
section for resellers.)
I have been happy with all the US manufactured blades in the Airmaster Hub.
And NO, you personally can't change the blades yourself.
Best Regards,
Bud Yerly
US Airmaster Dealer
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