Hello All
Wow, I have just seen the many replies received from last night, I am
slightly embarrassed at taking over the forum at least temporarily. Thank
you all for taking the time to reply, I will try to be brief in setting out
where I think I am.
As I mentioned I have been asked by the LAA to carry out the measurements to
comply with CS-VLA 925 which is essentially what Bud outlines in his last
paragraph (and thanks again Bud for your input, I intend forwarding your
replies to the LAA if you don't mind?).However at the moment I am bound by
the rules here in the UK but hopefully Bud your comments will help. By the
way I think that you meant 9" in your last sentence?
As some of you have pointed out the XS set up has the engine slightly higher
and further forward than the classic so should provide greater clearance so
I was only interested to see if any other fully classic mono aircraft (UK
regulated, I should have said this in my original request) had fitted a 64"
prop.
It seems that Tim in NZ is the only one so far to have done it but sadly it
didn't help for a UK based aircraft (but good to hear that it works).
I must say that I am surprised that this doesn't seem to have been an issue
here in the UK before as most of the classics must surely have been Mono's?
So at present my aircraft is wings off in my workshop at home having the
engine replaced and I will now re fit the wings and carry out the weighing
versus clearance measurements and submit them to the LAA. As the lead time
for replacement blades is currently in excess of 3 months I am thinking that
maybe I will re fit the original prop (however unsuitable) at least to keep
me flying until possible new blades arrive.
Thank you all for your inputs on this so far, I would still be interested to
hear from any UK based Classic mono owners that might have a 64" prop
fitted.
Cheers
Mike
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Bud Yerly
Sent: 29 December 2021 22:05
Subject: RE: Europa-List: Re: Propeller Sizing
Mike,
The 64 inch prop is the blade length ideal for all versions of the 912ULS
and 914 equipped on the Europa Classic/XS/Mono/Trigear. It has the
recommended ground clearance for normal operations for the mono and trigear.
Propeller manufacturers know the max length for each of their blades to meet
the Rotax moment of inertia, bolt pattern and other factors. I've placed a
64 inch wide chord Warp on a 80HP Rotax and it just wouldn't turn it up to
speed and top end cruise suffered. So max length is based on engine torque.
Notes:
Warp Drive is comfortable with the Wide Chord (Standard) blade on high speed
aircraft from 64 to 67 inches. I've seen guys with 70 inch two blade Warp
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
aircraft / engine combinations. Airmaster is one of the few to actually
print 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 and
is the only length we recommend for the Europa 912ULS/914. The speed
decrease at cruise is only a knot slower for the 64 inch and the ground
clearance is in the ideal range.
In the paper I wrote on What propeller blade length and hub was ideal for
the Rotax engines, I commented that with most propellers of a 16 to22
degrees 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)
nothing good happens after 67 to 68 inches. Inertia goes up (Warp Drive
blades have high inertia) and lighter wood and composite props can be
longer, but at a speed penalty so I set the and had many prop builders hate
me for recommending "Nothing good happens after 68 inches on a constant
speed prop on a Rotax engine in my opinion." Sure, one can thin the tip way
down or 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
aircraft are:
(a) 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
airplane with tail wheel landing gear) between each propeller and the ground
with the landing gear statically deflected and in the level, normal takeoff,
or taxing attitude, whichever is most critical. In addition, for each
airplane with conventional landing gear struts using fluid or mechanical
means for absorbing landing shocks, there must be positive clearance between
the 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 meet
this 7 inch propeller clearance.
Best Regards,
Bud Yerly
-----Original Message-----
From: owner-europa-list-server@matronics.com
<owner-europa-list-server@matronics.com> On Behalf Of Mike
Sent: Wednesday, December 29, 2021 5:21 AM
Subject: RE: Europa-List: Re: Propeller Sizing
mike@nyumba.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" to
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: <mailto:owner-europa-list-server@matronics.com>
owner-europa-list-server@matronics.com
[ <mailto:owner-europa-list-server@matronics.com>
mailto:owner-europa-list-server@matronics.com] On Behalf Of
<mailto:budyerly@msn.com> budyerly@msn.com
Sent: 28 December 2021 16:44
Subject: Europa-List: Re: Propeller Sizing
budyerly@msn.com" < <mailto:budyerly@msn.com> 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 tapered
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 will
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 of
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 lead
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: <mailto:dirk.oyen1@telenet.be> dirk.oyen1@telenet.be
M: +32 477 25 80 28
Website:
<https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.propell
or.com%2F&data=04%7C01%7C%7C83afb0f859684abcf48c08d9cab586f8%7C84df9e7fe
9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637763703272349596%7CUnknown%7CTWFpbGZsb3d
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r.com%2F&data=04%7C01%7C%7C83afb0f859684abcf48c08d9cab586f8%7C84df9e7fe9
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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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