Today's Message Index:
----------------------
1. 04:20 AM - Re: Re: Firewall Boots (Tom Faulkner)
2. 06:04 AM - Elevator authority (Joe Spencer)
3. 07:24 AM - Slats (george.mueller@aurora.org)
4. 08:14 AM - Re: Slats again (John Bolding)
5. 08:49 AM - Slats (Joe Spencer)
6. 09:06 AM - Re: Slats (nyterminat@aol.com)
7. 09:07 AM - Re: Slats (nyterminat@aol.com)
8. 09:14 AM - Re: Slats (ricklach)
9. 10:03 AM - Re: Slats again (Joe Stevenson)
10. 10:39 AM - Slats (Joe Spencer)
11. 10:58 AM - Project Almost Done - Cleaning House... (Don Honabach)
12. 02:18 PM - Re: Slats again (JG)
13. 05:15 PM - Re: Slats again (kmccune)
14. 06:03 PM - Re: Slats again (Graeme)
15. 07:26 PM - Re: Slats again (pdknight)
16. 08:33 PM - A question of horsepower... (pdknight)
17. 09:05 PM - Re: Slats (CHAS R BYBEE)
18. 09:46 PM - Re: A question of horsepower... (Graeme)
19. 09:53 PM - Re: A question of horsepower... (jetboy)
20. 10:10 PM - Re: Slats again (lane_jones)
21. 10:13 PM - Re: Slats again (lane_jones)
Message 1
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| Subject: | Re: Firewall Boots |
Dennis
The shop I went to knew the number for what I wanted and ordered it.
Tom
Message 2
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| Subject: | Elevator authority |
True. I can't measure any loss of STOL with the VGs. There is no real
world loss in my experience. I was able to duplicate JGs claims on speed
gains...but the real benefit is better low speed handling and same
cruise speed at reduced power/FUEL BURN...very big deal nowdays. The
slats are IMO just a marketing gimmick. They did work well on takeoff
but I couldn't tell that they were at all active on approach unless at a
forced very high AOA. Add strut fairings for an even more dramatic
decrease in drag and you have a fairly efficient airplane(with the
Rotax). FWIW.
Joe
>Exactly. I am willing to give up 10-15 feet of takeoff roll for ten
extra mph
>in cruise and better fuel economy. Even if the VGs had a slight
negative impact
>on the STOL capabilities, it would still have extraordinary ability to
get
>in and out of just about anywhere.
Message 3
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Just another data point regarding the question about slats vs vgs, if I
was doing it over again, I would: 1) build the wing without slats (adding
vgs of course); and 2) build the wing longer. I didn't like having my
slat brackets out in the wind, but I didn't want to cut them completely
off either, so I have left about 3/4" of my slat brackets on, and have
fabricated a mounting system so I can add the slats back on if I ever want
to. But they will be mostly collecting dust on the the hanger wall.
Other mods that I have done recently: I added a George Race type towbar
fitting to the nosewheel and bought a piper towbar for $50. I also
fabricated a fiberglass cover for the BRS bridle on top of the fuselage.
Before that I just had the bridle covered with leading edge tape, which
was starting to come off in places.
My next project is to fabricate strut fairings. I have looked at
different options but I think I will go with making them out of .016
6061-t6.
Separately, I get the digest version so I can't selectively delete flicka,
so I would vote to ban him if possible. I am all for diversity of opinion
but this horse operates outside the bounds of civil discourse.
George in Milwaukee
N701GM 42 hours flying
Message 4
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The little bit of GOOD information I found on the subject 2-3 yrs ago
indicated that the best performance increase when slats were
incorporated was on airfoils 15% or THINNER. The 65018 is already 18%
so in my feeble mind it is like putting lipstick on a pig. I REALLY
wish someone with a flying airplane would go to the trouble of building
either a new wing with the FULL 65018 or remove their standard 701
leading edge and replace with a full size nose rib.
I'll even beat out the ribs if someone wants to document the results. My
airplane will have this mod but life (and $$$ paying projects in the
hangar) is getting in the way of steady progress on my 701.
My thought is that because of the fact that the slat has been proved to
not contribute much/any (you choose) to lift during cruise, the extra 10
sq. ft. + of wing area you pick up when you put on the full size nose
will help on both ends of the speed range (over the bastard airfoil you
are left with when you remove the slats). This is just a little better
than a wild ass guess but seems to have been born out by the Savannah
however. It will also move the center of lift forward a bit which will
help with a heavier engine.
For all you float guys out there another thing that bears consideration
is the fact that the slats don't really start doing their thing until
you reach an AOA that is GREATER than the AOA you can achieve on either
landing or takeoff due to the float afterbody.
The question becomes why add weight, complexity, building time, expense
etc for something that does absolutely nothing for you. I couldn't
find a reason either. Maybe I'm just missing something , certainly
happened before.
I fully understand that this gets firmly into the "EXPERIMENTAL" aspect
of our hobby and am not suggesting that anybody follow suit without
doing their OWN homework.
This has all been hashed over more than once here but few of the newer
members (or old ones) search the archives so those that have heard all
this drivel before just hit delete.
I also concur with Joe's findings, I flew the 40 hr test time on Brett's
701 and the last few flights were sans slats with VG's (also on the
elevator, THOSE help a BUNCH), handled much better on the low end with
no loss of short field performance that I could tell.
LO&SLO John
----- Original Message -----
From: Joe Spencer
To: Zenith701801-List@matronics.com
Sent: Thursday, September 04, 2008 8:06 AM
Subject: Zenith701801-List: Elevator authority
True. I can't measure any loss of STOL with the VGs. There is no real
world loss in my experience. I was able to duplicate JGs claims on speed
gains...but the real benefit is better low speed handling and same
cruise speed at reduced power/FUEL BURN...very big deal nowdays. The
slats are IMO just a marketing gimmick. They did work well on takeoff
but I couldn't tell that they were at all active on approach unless at a
forced very high AOA. Add strut fairings for an even more dramatic
decrease in drag and you have a fairly efficient airplane(with the
Rotax). FWIW.
Joe
Message 5
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>My next project is to fabricate strut fairings. I have looked >at
>different options but I think I will go with making them out >of .016
>6061-t6
That's what I did. It was quite a bit of work but well worth it as has
been documented here before. When the strut fairings are combined with
the no slats/vg's the plane feels like it's been set free. The only
thing I have found that some might fault is the glide angle is much
flatter of course because the drag is so dramatically reduced but the
thing slips so well with the slab side that it's of no consequence.
Rpm/fuel burn/noise/engine wear/buffet are all down, some
dramatically...a vastly improved airplane.
Speaking of buffet; there are lots of opportunities for simple cleanup
in the tail area, where it seemed a lot of the airframe buffet/vibration
was coming from on mine. I faired in the nasty pocket under the rudder
leading edge with foam and bondo, and under the HS leading edge with
.016 and of course the VGs under the elevator. What a difference.
All those little cleanups add up to free fuel.
Joe
Message 6
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Joe, Could you post some pictues of the cleanup of the tail area?
Bob Spudis
Message 7
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Joe, Could you post some pictues of the cleanup of the tail area?
Bob Spudis
Message 8
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Hi Joe,
Ive been thinking about cleaning up the tail area where the Rudder, horizontal
stabilizer and fuselage come together. It sounds like you have done just that.
I would love to see some pictures of what you did and a little more conversation
as to the results. Some people think trying to clean up a box like a 701
is a waste of time, but I think any improvement gained are free performance gains.
Rick
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p 2539#202539
Message 9
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Excellent post John and answer's a question about the 701 airfoil I'd had f
or some time. I've held off on a 701 build due to the severe trade off in c
ruise speed for excellent STOL preformance as I knew other's had found alte
rnative solutions that worked very well for them. Guess I'll have to start
thinking along the lines of a 701 build in a bit as I am most pleased with
it's overall size after a little bit of tweaking for leg and headroom. Some
times an answer is right in front of you but it has to be pointed out to yo
u by another person. That's called information sharing and it is one of the
positive aspects of experimental avaition.=0A=0AJoe=0A=0A=0A=0A----- Origi
nal Message ----=0AFrom: John Bolding <jnbolding1@teleshare.net>=0ATo: zeni
th701801-list@matronics.com=0ASent: Thursday, September 4, 2008 10:07:42 AM
=0ASubject: Re: Zenith701801-List: Slats again=0A=0A=0AThe little bit of GO
OD information I found on the subject 2-3 yrs ago indicated that the best p
erformance increase when slats were incorporated was-on airfoils 15% or T
HINNER.- The 65018 is already-18% so in my feeble mind it is like putti
ng lipstick on a pig.- I REALLY wish someone with a flying airplane would
go to the trouble of building either a new wing with the FULL 65018 or rem
ove their standard 701 leading edge and replace with a full size nose rib.
=0AI'll even beat out the ribs if someone wants to document the results. My
airplane will have this mod but life (and $$$ paying projects in the hanga
r) is getting in the way of-steady progress on my 701.=0A-=0AMy-thoug
ht is that because of the fact that the slat has been proved to not contrib
ute much/any (you choose) to lift during cruise, the extra 10 sq. ft.-+
-of wing area you pick up when you put on the full size nose will help on
both ends of the speed range (over the bastard airfoil you are left with w
hen you remove the slats). This is just a little better than a wild ass gue
ss but seems to have been born out by the Savannah however. It will also mo
ve the center of lift forward a bit which will help with a heavier engine.
=0A-=0AFor all you float guys out there another thing that bears consider
ation is the fact that the slats don't really start doing their thing until
you reach an AOA that is GREATER than the AOA you can achieve on either la
nding or takeoff due to the float afterbody.=0AThe question becomes why add
weight, complexity, building time, expense etc for something that does abs
olutely nothing for you.---- -I couldn't find a reason either. Ma
ybe I'm just missing something , certainly happened before.=0A-=0AI fully
understand that this gets firmly into the "EXPERIMENTAL" aspect of our hob
by and am not suggesting that anybody follow suit without doing their OWN h
omework.=0AThis has all been hashed over more than once here but few of the
newer members (or old ones) search the archives so those that have heard a
ll this drivel before just hit delete.=0AI also concur with Joe's findings,
I flew the 40 hr test time on Brett's 701 and the last few flights were sa
ns slats with VG's (also on the elevator, THOSE help a BUNCH), handled- m
uch better on the low end with no loss of short field performance that I co
uld tell.=0A-=0ALO&SLO--- John=0A-=0A=0A=0A=0A=0A------ Origina
l Message ----- =0AFrom: Joe Spencer =0ATo: Zenith701801-List@matronics.com
=0ASent: Thursday, September 04, 2008 8:06 AM=0ASubject: Zenith701801-List
: Elevator authority=0A=0ATrue. I can't measure any loss of STOL with the V
Gs. There is no real world loss in my experience. I was able to duplicate J
Gs claims on speed gains...but the real benefit is better low speed handlin
g and same cruise speed at reduced power/FUEL BURN...very big deal nowdays.
The slats are IMO just a marketing gimmick. They did work well on takeoff
but I couldn't tell that they were at all active on approach unless at a fo
rced very high AOA. Add strut fairings for an even more dramatic decrease i
n drag and-you have a fairly efficient airplane(with the Rotax). FWIW.=0A
===============0A=0A=0A
Message 10
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>I would love to see some pictures of what you did and a >little more
conversation
>as to the results
I will send a few pics to somebody who already knows how to post them
and they can post them if they like. I'm a little short on time right
now trying to get things together for a trip...who wants them?
I tried to measure a speed gain with the tail cleanup and kept getting
varying results since it's so small it's hard for me to accurately
measure...the one that came up most often was 2.25 mph IIRC. Not
definitive but indicative. Call it a couple mph...not a whole lot but it
adds up and it's near free and did make it smoother. And it looks better
to me and is light. As far as cleanup on this plane being a waste of
time goes...it's SO crudely done that it can be easily improved. I never
consider free speed/efficiency a waste, personally.
Joe
Message 11
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| Subject: | Project Almost Done - Cleaning House... |
After over 10 years I'm almost done with my Zodiac 601HDS project (yes,
HDS) and I'm cleaning out/selling off the extras to make a little piece
in the family...
I've put up 2 Electric Gyros Indicators on eBay if anyone is interested:
RCA15AK-1 14V Electric Directional Gyro (Lighted)
http://tinyurl.com/6n66vm
RCA26AK-1 14V Electric Attitude Indicator Gyro (Lighted)
http://tinyurl.com/5nnfuu
Both are brand new, have zero hours and were bought at R.C. Allen Booth
at Oshkosh.
Don Honabach
Tempe, AZ
601HDS
Message 12
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The little bit of GOOD information I found on the subject 2-3 yrs ago
indicated that the best performance increase when slats were
incorporated was on airfoils 15% or THINNER. The 65018 is already 18%
so in my feeble mind it is like putting lipstick on a pig.
Right on JohnB. This is a subject that's been perculating in my mine
lately, and I'm getting ready to write up an analysis when I get the
time. When you look at the other aircraft that use slats successfully,
Helio Courier, Rallye, Feisler Storch, and the PegaStol wing, all are
about 12% thick. And more significantly, very 'lean' on the upper
surface of the leading edge - very different from that 18% thick and
very 'fat' leading edge of the 701 wing. That sure will affect the
airflow thro the slot, and the angle with which it intersects the flow
over the top. These other slats also deploy out and below the bottom
edge of the wing, which effectively increases the camber of that thinner
wing. The 701 originally had the slats mounted so that they projected
below the wing, but that caused too much turbulence at cruise for those
fixed slats, so they were moved up to where they are now in order to
improve cruise. Now have a look at the dramatic effect that slats can
have on the Super Cubs with a slim ClarkY or very similar airfoil, see
http://www.youtube.com/watch?v=jLa4BikYWtc&feature=related
No 701 can hang on the prop with as much control as this! Very
impressive!
Now the flip side of this situation. I've long wondered what the ideal
airfoil would be for VGs to have the best effect. Now I'm beginning to
realize that that big fat airfoil left behind after the slats are
removed from a 701 is just about ideal for VGs. 'Experts' still keep
predicting that VGs won't have much effect on a high lift wing... Well,
all my experience shows just the opposite - with an airfoil that's
already very good at low speed airflow, the VGs put the 'icing on the
cake'. That big fat leading edge on the 701 wing turns out to be an
ideal platform for VGs. It's a really unexpected but worthwhile
discovery.
JohnG
www.stolspeed.com
----- Original Message -----
From: John Bolding
To: zenith701801-list@matronics.com
Sent: Friday, September 05, 2008 1:07 AM
Subject: Re: Zenith701801-List: Slats again
I REALLY wish someone with a flying airplane would go to the trouble
of building either a new wing with the FULL 65018 or remove their
standard 701 leading edge and replace with a full size nose rib.
I'll even beat out the ribs if someone wants to document the results.
My airplane will have this mod but life (and $$$ paying projects in the
hangar) is getting in the way of steady progress on my 701.
My thought is that because of the fact that the slat has been proved
to not contribute much/any (you choose) to lift during cruise, the extra
10 sq. ft. + of wing area you pick up when you put on the full size nose
will help on both ends of the speed range (over the bastard airfoil you
are left with when you remove the slats). This is just a little better
than a wild ass guess but seems to have been born out by the Savannah
however. It will also move the center of lift forward a bit which will
help with a heavier engine.
For all you float guys out there another thing that bears
consideration is the fact that the slats don't really start doing their
thing until you reach an AOA that is GREATER than the AOA you can
achieve on either landing or takeoff due to the float afterbody.
The question becomes why add weight, complexity, building time,
expense etc for something that does absolutely nothing for you. I
couldn't find a reason either. Maybe I'm just missing something ,
certainly happened before.
I fully understand that this gets firmly into the "EXPERIMENTAL"
aspect of our hobby and am not suggesting that anybody follow suit
without doing their OWN homework.
This has all been hashed over more than once here but few of the newer
members (or old ones) search the archives so those that have heard all
this drivel before just hit delete.
I also concur with Joe's findings, I flew the 40 hr test time on
Brett's 701 and the last few flights were sans slats with VG's (also on
the elevator, THOSE help a BUNCH), handled much better on the low end
with no loss of short field performance that I could tell.
LO&SLO John
----- Original Message -----
From: Joe Spencer
To: Zenith701801-List@matronics.com
Sent: Thursday, September 04, 2008 8:06 AM
Subject: Zenith701801-List: Elevator authority
True. I can't measure any loss of STOL with the VGs. There is no
real world loss in my experience. I was able to duplicate JGs claims on
speed gains...but the real benefit is better low speed handling and same
cruise speed at reduced power/FUEL BURN...very big deal nowdays. The
slats are IMO just a marketing gimmick. They did work well on takeoff
but I couldn't tell that they were at all active on approach unless at a
forced very high AOA. Add strut fairings for an even more dramatic
decrease in drag and you have a fairly efficient airplane(with the
Rotax). FWIW.
Joe
Message 13
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That was amazing!
Kevin
--------
Mark Twain: Twenty years from now you will be more disappointed by the things that
you didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore. Dream.
Discover.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p 2649#202649
Message 14
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WATCHED THE VIDEO.
I WONDER HOW MANY HP THE CUB HAS??
THE CANYON SURFING VIDEO WITH THE 701 IS ALSO GREAT TO WATCH.
GRAEMECNS
----- Original Message -----
From: JG
To: zenith701801-list@matronics.com
Sent: Friday, September 05, 2008 7:17 AM
Subject: Re: Zenith701801-List: Slats again
The little bit of GOOD information I found on the subject 2-3 yrs ago
indicated that the best performance increase when slats were
incorporated was on airfoils 15% or THINNER. The 65018 is already 18%
so in my feeble mind it is like putting lipstick on a pig.
Right on JohnB. This is a subject that's been perculating in my mine
lately, and I'm getting ready to write up an analysis when I get the
time. When you look at the other aircraft that use slats successfully,
Helio Courier, Rallye, Feisler Storch, and the PegaStol wing, all are
about 12% thick. And more significantly, very 'lean' on the upper
surface of the leading edge - very different from that 18% thick and
very 'fat' leading edge of the 701 wing. That sure will affect the
airflow thro the slot, and the angle with which it intersects the flow
over the top. These other slats also deploy out and below the bottom
edge of the wing, which effectively increases the camber of that thinner
wing. The 701 originally had the slats mounted so that they projected
below the wing, but that caused too much turbulence at cruise for those
fixed slats, so they were moved up to where they are now in order to
improve cruise. Now have a look at the dramatic effect that slats can
have on the Super Cubs with a slim ClarkY or very similar airfoil, see
http://www.youtube.com/watch?v=jLa4BikYWtc&feature=related
No 701 can hang on the prop with as much control as this! Very
impressive!
Now the flip side of this situation. I've long wondered what the
ideal airfoil would be for VGs to have the best effect. Now I'm
beginning to realize that that big fat airfoil left behind after the
slats are removed from a 701 is just about ideal for VGs. 'Experts'
still keep predicting that VGs won't have much effect on a high lift
wing... Well, all my experience shows just the opposite - with an
airfoil that's already very good at low speed airflow, the VGs put the
'icing on the cake'. That big fat leading edge on the 701 wing turns
out to be an ideal platform for VGs. It's a really unexpected but
worthwhile discovery.
JohnG
www.stolspeed.com
----- Original Message -----
From: John Bolding
To: zenith701801-list@matronics.com
Sent: Friday, September 05, 2008 1:07 AM
Subject: Re: Zenith701801-List: Slats again
I REALLY wish someone with a flying airplane would go to the
trouble of building either a new wing with the FULL 65018 or remove
their standard 701 leading edge and replace with a full size nose rib.
I'll even beat out the ribs if someone wants to document the
results. My airplane will have this mod but life (and $$$ paying
projects in the hangar) is getting in the way of steady progress on my
701.
My thought is that because of the fact that the slat has been proved
to not contribute much/any (you choose) to lift during cruise, the extra
10 sq. ft. + of wing area you pick up when you put on the full size nose
will help on both ends of the speed range (over the bastard airfoil you
are left with when you remove the slats). This is just a little better
than a wild ass guess but seems to have been born out by the Savannah
however. It will also move the center of lift forward a bit which will
help with a heavier engine.
For all you float guys out there another thing that bears
consideration is the fact that the slats don't really start doing their
thing until you reach an AOA that is GREATER than the AOA you can
achieve on either landing or takeoff due to the float afterbody.
The question becomes why add weight, complexity, building time,
expense etc for something that does absolutely nothing for you. I
couldn't find a reason either. Maybe I'm just missing something ,
certainly happened before.
I fully understand that this gets firmly into the "EXPERIMENTAL"
aspect of our hobby and am not suggesting that anybody follow suit
without doing their OWN homework.
This has all been hashed over more than once here but few of the
newer members (or old ones) search the archives so those that have heard
all this drivel before just hit delete.
I also concur with Joe's findings, I flew the 40 hr test time on
Brett's 701 and the last few flights were sans slats with VG's (also on
the elevator, THOSE help a BUNCH), handled much better on the low end
with no loss of short field performance that I could tell.
LO&SLO John
----- Original Message -----
From: Joe Spencer
To: Zenith701801-List@matronics.com
Sent: Thursday, September 04, 2008 8:06 AM
Subject: Zenith701801-List: Elevator authority
True. I can't measure any loss of STOL with the VGs. There is no
real world loss in my experience. I was able to duplicate JGs claims on
speed gains...but the real benefit is better low speed handling and same
cruise speed at reduced power/FUEL BURN...very big deal nowdays. The
slats are IMO just a marketing gimmick. They did work well on takeoff
but I couldn't tell that they were at all active on approach unless at a
forced very high AOA. Add strut fairings for an even more dramatic
decrease in drag and you have a fairly efficient airplane(with the
Rotax). FWIW.
Joe
href="http://www.matronics.com/Navigator?Zenith701801-List">http://www.
matronics.com/Navigator?Zenith701801-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
-------------------------------------------------------------------------
-----
Checked by AVG - http://www.avg.com
9/4/2008 6:57 AM
Message 15
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There is an article about this aircraft in the May 2008 issue of Sport Aviation.
Mackey designed it around a Super Cub wing, put 8 ft long flaps and 8 ft long
ailerons on it, did mucho pimping on he airframe, and came up with this pretty
impressive design. The article stated that it has a 150 hp Lycoming o-320
and an 82" prop. Shows a Vmca of 18 mph at 1450 lbs and 26 mph at 1800 pounds.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p 2666#202666
Message 16
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| Subject: | A question of horsepower... |
I was just looking over the numbers on the Zenith webpage for performance with
an 80hp powerplant versus a 100hp powerplant. Using their Rotax example, the
80 hp engine will give a "dual" takeoff roll of 115 ft. The 100 hp engine gives
a takeoff of 90 ft. Therefore, 2000 extra bucks gets you a 25 ft shorter takeoff
roll, and giving an extra 100 fpm climb.
Great Plains redrives 1915cc engine advertises 85 hp on takeoff and 65 in cruise,
while the 2180 gives 105 on takeoff and 70 in cruise. The price difference
is much closer than with the rotax engines, being 600 more for the 105 hp model.
It gives 18 more hp on takeoff, but only 5 more in cruise. There is a question
coming up somewhere in this rant.
>From what I have heard, few people can match the factory performance estimates,
even with the exact same engines. Real world wise, what are you all seeing
from your aircraft, such as with an 80hp and 100hp? Obviously, 20 extra hp has
its benefits, but 25 ft worth of benefit? Is the extra expenditure worth that
few extra hp?
I ask only because I am trying to get my powerplant decision narrowed down soon,
and my experience in general aviation and prop aircraft is somewhat limited.
Thanks for the input.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p 2675#202675
Message 17
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Joe can you send some pictures of how you cleaned up the the tail of the
701 Bob aa9td@verizon.net
----- Original Message -----
From: Joe Spencer
To: Zenith701801-List@matronics.com
Sent: Thursday, September 04, 2008 12:41 PM
Subject: Zenith701801-List: Slats
>I would love to see some pictures of what you did and a >little more
conversation
>as to the results
I will send a few pics to somebody who already knows how to post them
and they can post them if they like. I'm a little short on time right
now trying to get things together for a trip...who wants them?
I tried to measure a speed gain with the tail cleanup and kept getting
varying results since it's so small it's hard for me to accurately
measure...the one that came up most often was 2.25 mph IIRC. Not
definitive but indicative. Call it a couple mph...not a whole lot but it
adds up and it's near free and did make it smoother. And it looks better
to me and is light. As far as cleanup on this plane being a waste of
time goes...it's SO crudely done that it can be easily improved. I never
consider free speed/efficiency a waste, personally.
Joe
Message 18
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| Subject: | Re: A question of horsepower... |
If you have the extra $2000 you will not go wrong with the 100hp
115ft dual with 80 HP would have to be at sea level on a cold day.
Ask yourself
do you fly in cold weather at sea level all the time
do you fly by your self
how heavy are you and your co passenger
repeating
If you have the extra $2000 you will not go wrong with the 100hp
Graemecns
----- Original Message -----
From: "pdknight" <pdknightcap@yahoo.com>
Sent: Friday, September 05, 2008 1:33 PM
Subject: Zenith701801-List: A question of horsepower...
> <pdknightcap@yahoo.com>
>
> I was just looking over the numbers on the Zenith webpage for performance
> with an 80hp powerplant versus a 100hp powerplant. Using their Rotax
> example, the 80 hp engine will give a "dual" takeoff roll of 115 ft. The
> 100 hp engine gives a takeoff of 90 ft. Therefore, 2000 extra bucks gets
> you a 25 ft shorter takeoff roll, and giving an extra 100 fpm climb.
> Great Plains redrives 1915cc engine advertises 85 hp on takeoff and 65 in
> cruise, while the 2180 gives 105 on takeoff and 70 in cruise. The price
> difference is much closer than with the rotax engines, being 600 more for
> the 105 hp model. It gives 18 more hp on takeoff, but only 5 more in
> cruise. There is a question coming up somewhere in this rant.
>>From what I have heard, few people can match the factory performance
>>estimates, even with the exact same engines. Real world wise, what are
>>you all seeing from your aircraft, such as with an 80hp and 100hp?
>>Obviously, 20 extra hp has its benefits, but 25 ft worth of benefit? Is
>>the extra expenditure worth that few extra hp?
> I ask only because I am trying to get my powerplant decision narrowed down
> soon, and my experience in general aviation and prop aircraft is somewhat
> limited. Thanks for the input.
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p 2675#202675
>
>
--------------------------------------------------------------------------------
Checked by AVG - http://www.avg.com
6:54 PM
Message 19
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| Subject: | Re: A question of horsepower... |
a better way to ask this question is :
have you changed or wanted to change engines, with / from what type and why?
What you summised about the Rotax and corresponding VW choices is quite reasonable.
Can't remember if it is Valley or Great Plains that have the water cooled
/ dual ignition option, but they state clearly its to provide an alternative
to the Rotax. Of concern and you can read it in detail on one of those websites
is the taper coupling used on some crankshafts, I tend to prefer the flywheel
end drive for the more reliable connection.
Another issue is cooling, a 701 with 2180 VW and redrive burnt it up in under 40
hrs although that failure was put down as lean mixture and he's flying again.
Another 701 here had a Corvair but replaced it with a Jabiru 2200 as the Corvair
proved too heavy and thirsty for 2 up and cross country.
I have the Jabiru 2200, with a custom matched wood prop, and its a good balance
for me. its not worth quoting figures, people pick on the smallest of discrepancies,
basically what you get is the product of thrust minus penalty of weight.
Using a redrive allows a large 2 blade prop for max efficiency, but poor air
cooling (for the 701) and higher weight. Using a 2 stroke cuts the weight and
reliability, in my direct experience. The direct drive Jabiru suffers due to
practical limitation of 64" prop dia. for the rpm it turns, loosing 5% thrust
efficiency, thats why a 582 powered 701 can climb just about the same.
While the claimed TO distances might appear the only difference, it matters not
because the plane needs more distance to land in. Climb rate for me is the important
factor, and of known available packages the Rotax 914 would be my first
choice, going down in price I'd consider the Jabiru 3300 then perhaps the 80
hp 912, Jabiru 2200 or one of the VW variants (but pick a good one, not sure
they are all equal)
The reason I passed on the most popular 912s is it has proved harsh operating in
the 701, more stressed than the 80hp, besides if I needed the extra power I'd
rather supercharge or turbo the cheaper 80hp.
I could not consider this option on a Jabiru or VW, they dont stay together for
long enough on their own, This reliability / longevity factor is probably more
a deciding factor.
As I have only 250 hrs on the Jabiru I cannot be certain of its future, it has
not faltered in any way to date, I am well aware of many others (Rotax, VW and
Jabiru) that have experienced a high 'no go' / stoppage rate.
Apologies if this answer got a bit long, just my thoughts which are constantly
updating
Ralph
--------
Ralph - CH701 / 2200a
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p 2686#202686
Message 20
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here is another interesting one
http://www.youtube.com/watch?v=z985xdXW-3w
Lane Jones
CH 701 3300
Do Not Archive
----- Original Message -----
From: Graeme
To: zenith701801-list@matronics.com
Sent: Thursday, September 04, 2008 8:59 PM
Subject: Re: Zenith701801-List: Slats again
WATCHED THE VIDEO.
I WONDER HOW MANY HP THE CUB HAS??
THE CANYON SURFING VIDEO WITH THE 701 IS ALSO GREAT TO WATCH.
GRAEMECNS
----- Original Message -----
From: JG
To: zenith701801-list@matronics.com
Sent: Friday, September 05, 2008 7:17 AM
Subject: Re: Zenith701801-List: Slats again
The little bit of GOOD information I found on the subject 2-3 yrs
ago indicated that the best performance increase when slats were
incorporated was on airfoils 15% or THINNER. The 65018 is already 18%
so in my feeble mind it is like putting lipstick on a pig.
Right on JohnB. This is a subject that's been perculating in my
mine lately, and I'm getting ready to write up an analysis when I get
the time. When you look at the other aircraft that use slats
successfully, Helio Courier, Rallye, Feisler Storch, and the PegaStol
wing, all are about 12% thick. And more significantly, very 'lean' on
the upper surface of the leading edge - very different from that 18%
thick and very 'fat' leading edge of the 701 wing. That sure will
affect the airflow thro the slot, and the angle with which it intersects
the flow over the top. These other slats also deploy out and below the
bottom edge of the wing, which effectively increases the camber of that
thinner wing. The 701 originally had the slats mounted so that they
projected below the wing, but that caused too much turbulence at cruise
for those fixed slats, so they were moved up to where they are now in
order to improve cruise. Now have a look at the dramatic effect that
slats can have on the Super Cubs with a slim ClarkY or very similar
airfoil, see
http://www.youtube.com/watch?v=jLa4BikYWtc&feature=related
No 701 can hang on the prop with as much control as this! Very
impressive!
Now the flip side of this situation. I've long wondered what the
ideal airfoil would be for VGs to have the best effect. Now I'm
beginning to realize that that big fat airfoil left behind after the
slats are removed from a 701 is just about ideal for VGs. 'Experts'
still keep predicting that VGs won't have much effect on a high lift
wing... Well, all my experience shows just the opposite - with an
airfoil that's already very good at low speed airflow, the VGs put the
'icing on the cake'. That big fat leading edge on the 701 wing turns
out to be an ideal platform for VGs. It's a really unexpected but
worthwhile discovery.
JohnG
www.stolspeed.com
----- Original Message -----
From: John Bolding
To: zenith701801-list@matronics.com
Sent: Friday, September 05, 2008 1:07 AM
Subject: Re: Zenith701801-List: Slats again
I REALLY wish someone with a flying airplane would go to the
trouble of building either a new wing with the FULL 65018 or remove
their standard 701 leading edge and replace with a full size nose rib.
I'll even beat out the ribs if someone wants to document the
results. My airplane will have this mod but life (and $$$ paying
projects in the hangar) is getting in the way of steady progress on my
701.
My thought is that because of the fact that the slat has been
proved to not contribute much/any (you choose) to lift during cruise,
the extra 10 sq. ft. + of wing area you pick up when you put on the full
size nose will help on both ends of the speed range (over the bastard
airfoil you are left with when you remove the slats). This is just a
little better than a wild ass guess but seems to have been born out by
the Savannah however. It will also move the center of lift forward a bit
which will help with a heavier engine.
For all you float guys out there another thing that bears
consideration is the fact that the slats don't really start doing their
thing until you reach an AOA that is GREATER than the AOA you can
achieve on either landing or takeoff due to the float afterbody.
The question becomes why add weight, complexity, building time,
expense etc for something that does absolutely nothing for you. I
couldn't find a reason either. Maybe I'm just missing something ,
certainly happened before.
I fully understand that this gets firmly into the "EXPERIMENTAL"
aspect of our hobby and am not suggesting that anybody follow suit
without doing their OWN homework.
This has all been hashed over more than once here but few of the
newer members (or old ones) search the archives so those that have heard
all this drivel before just hit delete.
I also concur with Joe's findings, I flew the 40 hr test time on
Brett's 701 and the last few flights were sans slats with VG's (also on
the elevator, THOSE help a BUNCH), handled much better on the low end
with no loss of short field performance that I could tell.
LO&SLO John
----- Original Message -----
From: Joe Spencer
To: Zenith701801-List@matronics.com
Sent: Thursday, September 04, 2008 8:06 AM
Subject: Zenith701801-List: Elevator authority
True. I can't measure any loss of STOL with the VGs. There is no
real world loss in my experience. I was able to duplicate JGs claims on
speed gains...but the real benefit is better low speed handling and same
cruise speed at reduced power/FUEL BURN...very big deal nowdays. The
slats are IMO just a marketing gimmick. They did work well on takeoff
but I couldn't tell that they were at all active on approach unless at a
forced very high AOA. Add strut fairings for an even more dramatic
decrease in drag and you have a fairly efficient airplane(with the
Rotax). FWIW.
Joe
href="http://www.matronics.com/Navigator?Zenith701801-List">http://www.
matronics.com/Navigator?Zenith701801-List
href="http://forums.matronics.com">http://forums.matronics.com
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Message 21
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----- Original Message -----
From: lane_jones
To: zenith701801-list@matronics.com
Sent: Friday, September 05, 2008 1:10 AM
Subject: Re: Zenith701801-List: Slats again
here is another interesting one
http://www.youtube.com/watch?v=5zioQVUSWcY&feature=related.
and
http://www.youtube.com/watch?v=z985xdXW-3w
Lane Jones
CH 701 3300
Do Not Archive
----- Original Message -----
From: Graeme
To: zenith701801-list@matronics.com
Sent: Thursday, September 04, 2008 8:59 PM
Subject: Re: Zenith701801-List: Slats again
WATCHED THE VIDEO.
I WONDER HOW MANY HP THE CUB HAS??
THE CANYON SURFING VIDEO WITH THE 701 IS ALSO GREAT TO WATCH.
GRAEMECNS
----- Original Message -----
From: JG
To: zenith701801-list@matronics.com
Sent: Friday, September 05, 2008 7:17 AM
Subject: Re: Zenith701801-List: Slats again
The little bit of GOOD information I found on the subject 2-3 yrs
ago indicated that the best performance increase when slats were
incorporated was on airfoils 15% or THINNER. The 65018 is already 18%
so in my feeble mind it is like putting lipstick on a pig.
Right on JohnB. This is a subject that's been perculating in my
mine lately, and I'm getting ready to write up an analysis when I get
the time. When you look at the other aircraft that use slats
successfully, Helio Courier, Rallye, Feisler Storch, and the PegaStol
wing, all are about 12% thick. And more significantly, very 'lean' on
the upper surface of the leading edge - very different from that 18%
thick and very 'fat' leading edge of the 701 wing. That sure will
affect the airflow thro the slot, and the angle with which it intersects
the flow over the top. These other slats also deploy out and below the
bottom edge of the wing, which effectively increases the camber of that
thinner wing. The 701 originally had the slats mounted so that they
projected below the wing, but that caused too much turbulence at cruise
for those fixed slats, so they were moved up to where they are now in
order to improve cruise. Now have a look at the dramatic effect that
slats can have on the Super Cubs with a slim ClarkY or very similar
airfoil, see
http://www.youtube.com/watch?v=jLa4BikYWtc&feature=related
No 701 can hang on the prop with as much control as this! Very
impressive!
Now the flip side of this situation. I've long wondered what the
ideal airfoil would be for VGs to have the best effect. Now I'm
beginning to realize that that big fat airfoil left behind after the
slats are removed from a 701 is just about ideal for VGs. 'Experts'
still keep predicting that VGs won't have much effect on a high lift
wing... Well, all my experience shows just the opposite - with an
airfoil that's already very good at low speed airflow, the VGs put the
'icing on the cake'. That big fat leading edge on the 701 wing turns
out to be an ideal platform for VGs. It's a really unexpected but
worthwhile discovery.
JohnG
www.stolspeed.com
----- Original Message -----
From: John Bolding
To: zenith701801-list@matronics.com
Sent: Friday, September 05, 2008 1:07 AM
Subject: Re: Zenith701801-List: Slats again
I REALLY wish someone with a flying airplane would go to the
trouble of building either a new wing with the FULL 65018 or remove
their standard 701 leading edge and replace with a full size nose rib.
I'll even beat out the ribs if someone wants to document the
results. My airplane will have this mod but life (and $$$ paying
projects in the hangar) is getting in the way of steady progress on my
701.
My thought is that because of the fact that the slat has been
proved to not contribute much/any (you choose) to lift during cruise,
the extra 10 sq. ft. + of wing area you pick up when you put on the full
size nose will help on both ends of the speed range (over the bastard
airfoil you are left with when you remove the slats). This is just a
little better than a wild ass guess but seems to have been born out by
the Savannah however. It will also move the center of lift forward a bit
which will help with a heavier engine.
For all you float guys out there another thing that bears
consideration is the fact that the slats don't really start doing their
thing until you reach an AOA that is GREATER than the AOA you can
achieve on either landing or takeoff due to the float afterbody.
The question becomes why add weight, complexity, building time,
expense etc for something that does absolutely nothing for you. I
couldn't find a reason either. Maybe I'm just missing something ,
certainly happened before.
I fully understand that this gets firmly into the "EXPERIMENTAL"
aspect of our hobby and am not suggesting that anybody follow suit
without doing their OWN homework.
This has all been hashed over more than once here but few of the
newer members (or old ones) search the archives so those that have heard
all this drivel before just hit delete.
I also concur with Joe's findings, I flew the 40 hr test time on
Brett's 701 and the last few flights were sans slats with VG's (also on
the elevator, THOSE help a BUNCH), handled much better on the low end
with no loss of short field performance that I could tell.
LO&SLO John
----- Original Message -----
From: Joe Spencer
To: Zenith701801-List@matronics.com
Sent: Thursday, September 04, 2008 8:06 AM
Subject: Zenith701801-List: Elevator authority
True. I can't measure any loss of STOL with the VGs. There is
no real world loss in my experience. I was able to duplicate JGs claims
on speed gains...but the real benefit is better low speed handling and
same cruise speed at reduced power/FUEL BURN...very big deal nowdays.
The slats are IMO just a marketing gimmick. They did work well on
takeoff but I couldn't tell that they were at all active on approach
unless at a forced very high AOA. Add strut fairings for an even more
dramatic decrease in drag and you have a fairly efficient airplane(with
the Rotax). FWIW.
Joe
href="http://www.matronics.com/Navigator?Zenith701801-List">http://www.
matronics.com/Navigator?Zenith701801-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
href="http://www.matronics.com/Navigator?Zenith701801-List">http://www.
matronics.com/Navigator?Zenith701801-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
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