Hi ,
I am planning on building a canard either the VARIEZE or LONG-EZ
because I would like to build an aircraft to travel long distances.
One of the drawbacks of a canard is that it requires a long runway
for take off.
There is a canard called the IBIS Canard a wooden structure using a
direct drive air cooled VW 65 HP. His thinking behind it is that the
maximum rpm for propeller is 2700 so as the engine idles @ 1000 rpm
he reached Max propeller rpm @ 3700. He even says 85 HP would cause
extra fuel consumption.
https://www.junqua-aircraft.com/html/framegene.htm
I was wondering by having an increased HP with reduction drive and
relevant propeller, Can one dramatically shorten the take off
distance of a CANARD like the VARIEZE or LONG-EZ ?
Zahid Rahman
Sure! all it takes in HP. Go see Emon Hurley at Hurley Engineering
in Coventry and get him to build a P-port two rotor with 250 HP and
install it in a Long EZ.
If the prop is 50% efficent at 50 feet per second forward speed you
will have HP = 125 = 68750 pound feet per second.
So at 50 feet per second you have 1,375 pounds of thrust. That is
just about what a Long EZ weighs so basically the airplane will
accelerate initially at well over one G. One G is 32 feet per
second per second.
You will be doing about 80 MPH in about 3 seconds. and a couple of
hundred feet down the runway.
65 HP would barely make it fly.
With a p-port rotary it would do well over 200 MPH.
Paul Lamar
Hey Zahid,
I too am building a long EZ, actually I have two, and I bought a
rebuilt 13B out of a mazda to use. I am convinced Paul is right. Much
more HP and a smaller package. Keep us posted on your progress. This
is all new territory for me so I can use all the help I can find. A
friend has a bush plane that is fun to fly but you can’t get any
where with it as it is too slow. My wife and I love to frequent the
Moab Utah area… 1000 miles away, 2 days drive, but with a near 200
mph plane its only 5+ hours. I think I live on the edge of the
planet, I don’t know of anybody out here that has experience with
converting a rotary to aircraft use. I’m wondering… where is
Coventry? I bet its on the east coast. Is there anybody out here in
the Pacific northwest that knows their stuff? Specifically the Oregon
coast?
Regards Jess Choat.
This one has been flying for over 600 hours. Owned and built by Perry
Mick. The engine is solidly bolted into the air frame. It also has a
stock RX7 instrument panel. I uses a stock RX7 ECU.
Paul Lamar
Coventry (UK) is 99 miles from me and 5,500 miles from you. I Would
like use it to travel 3200 miles east of UK. Thanks for confirming a
two day travel. Thanks for the pics.
Zahid Rahman
Just to be clear and avoid misunderstanding by me.
The designer of wooden IBIS canard with EMPTY weight of 250 kgs
(550 lbs) is claiming to achieve flight with Direct Drive on VW
60HP. MAX. 2700 Propeller RPM @ 3700 engine RPM.
I know a builder is going to use on the (wooden) canard VW 80 HP
air cooled, so @ 3700 RPM it will be utilising 65 HP from the 80
HP.
Can I achieve the figures you suggested (above) on LONG-EZ EMPTY
weight 322 kgs (709 lbs) with P-PORTED 250 HP rotary with Direct
Drive ?
Zahid Rahman
Direct drive means no gear box. If the engine is turning 3700 RPM so
is the prop. A 3700 RPM prop is very inefficient indeed.
No! All rotaries require gear boxes. Rotaries make power with RPM
and not displacement. That is one of the reasons they can be so light
in weight. The prop must turn below 2700 RPM for efficiency.
A 60 HP airplane is not really suitable for 3200 mile cross country
trips. If you get a head wind you can drive faster. About 150 MPH is
needed for a reasonable cross country airplane. Of course a few
cross country flights have been done with less.
Paul Lamar
That's what I thought that a direct drive means no gearbox and the most
efficient prop is @ 2700 and engine rpm would also be 2700 rpm.
I am going to get back to that builder and ask what he meant by engine
idle-ing at 1000 rpm and the max propeller rpm reached is 3700 engine
rpm. It didn't make sense to me.
He was saying after 3700 rpm of engine propeller is useless which confused
me a bit as I thought like you that it would be 2700 rpm of engine and prop
would become inefficient.
Zahid Rahman
I would not say 3700 RPM is useless. Some F1 racers use it because the
rules don't allow gear boxes or turbo chargers. Your MPG will suffer
greatly.
BTW Coventry is in the UK. So is Zahid Rahman
Jess Choat, there are a couple of people in the Portland area that
have flying rotary powered airplanes. Perry Mick is in McMinville
and Steve Beckman is in Canby.
The Evergreen aviation museum with the Spruce Goose in McMinville
has grown into one of the finest aviation museums in the world.
Paul Lamar
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