Hangar Flying

Hangar Flying => Hangar Flying => Topic started by: thenrie on February 01, 2010, 11:56:02 AM

Title: some Varieze questions - looking for info and suggestions
Post by: thenrie on February 01, 2010, 11:56:02 AM

I am going to purchase my dad's Varieze project from him (price is just right).  It's a legit VE, 70% finished, 90% to go.  However, my thoughts seem to be a little different than his on some things.  While he was intending to make it a full IFR traveling aircraft, I am thinking more along the lines of light and fast.  I think that's what the VE was designed for.

The tub, wings, and canard are made, gear is mounted, all parts are there.  A Subaru E81 will power it.  It has wing cuffs and the VE winglet.  Other than Dad adding a landing light in the nose and the Subaru engine, I believe it is built to the plans.  It appears to be well-built with good craftsmanship (my dad bought it years ago in almost the same state it is in now).  I would appreciate some discussion/suggestions regarding the following topics.

-  I have read the wing cuffs work, but cost some knots.  There seems to be some disagreement regarding vortilons vs. trailing edge fences for reducing the approach/climb-out speed.  Should I remove the cuffs and add vortilons or fences?
-  Some have suggested the VE winglets are only useful for protecting the main wingtip in case of a tip-touch.  Others suggest the LE winglet on the VE improves flight characteristics of the wing in much the same way as TE fences.  Do I need winglets at all?
-  The original design of the VE had anhedral in the main wing due to the lack of control surfaces, relying on elevons in the canard for     control. There were some accidents during landing when a tip dropped and the pilot instinctively tried to correct using aileron rather than rudder (as per Rutan's instructions), thereby causing the canard to stall and nose-in.  Rutan then modified the design to include ailerons on the main wing and apparently went away from the VW engine.  That is when the weight started increasing.  The original plan had the empty weight at 320 lbs and used a 65hp VW conversion (per a 1976 Popular Mechanics article).  It seems empty weight to the plans is now about 1050 lbs.  Where did all the extra weight come from and where can weight safely be cut?
-  What is the max safe speed, built to the plans.  What can be done to increase it?
-  I have read the VE is now rated for +/-2.5 G.  How can that be increased?

To sum things up, I want to build the VE to be a light, fast, get-from-point-A-to-point-B-on-very-little-gas flying machine.  As I start my planning, I would ask for suggestions on what others have found to work and what to stay away from, what to keep and what to lose.  I am a member of EAA and will soon be a member of CSA.  I don't yet have dad's plans/newsletters in hand, and won't for a number of months.  I'm just excited and trying to look ahead.

Title: Re: some Varieze questions - looking for info and suggestions
Post by: go ez on February 01, 2010, 03:36:49 PM

Take off the wing cuffs and add the vortilons - they are mandatory and very effective. I have trailing edge wing fences too - they lower approach speed & give better viz on approach.
I removed the lower skegs as a safety feature since it makes the risk of a wing digging in during a forced landing less likely  - they do very little aerodynamically - unlike the Long ez where the lower winglet is necessary
Empty weight with an O-200 engine is between 600 (light) to 700 + (heavy). Rutan's N4EZ VE bare equipped with elevons weighed 525 (declared)with O-200 , while the addition of the ailerons, landing brake etc etc bought it to nearer 585
the 1050lbs  is the gross weight
VNE  max speed is 190 kts but a good cruise is 140 -150 kts
+2.5 G / -1.5 G  restriction is due to the risk that the spar to wing fittings transition may be faulty and is difficult to inspect on a completed a/c. If the wing fittings are exposed and you or an expert can see & be sure it is done right the G limit may be less of an issue. If you are that stage, I'd think about removing the wing fittings and alodineing them to avoid future corrosion problems - big job though.
I'd fit bigger tanks - I used  PVC foam instead of urethane & mine hold 34 US gallons total plus 3 US Gall fuselage tank/reserve - excellent range
Plans & CSA will be a real education
Good luck - a great airplane

Title: Re: some Varieze questions - looking for info and suggestions
Post by: dorr on February 14, 2010, 10:27:32 PM

I'm not in a Varieze - a few comments to add to this full response.

Larger tanks are good idea.

Al Fink also widened the interior from arm rest to upper longeron about 4" per side and the plane became wonderfully roomy - as Tackabury's Vari/Long is.

Burt designed the Long EZ because people were overloading the panel of the Varieze - keep the weight down - it is more critical in the Varieze - although I've seen them up over 800 lbs empty and flying fine way over book limits.

The Long EZ lower winglets are not necessary - despite Nat Puffer's tests of Cozy with longer and shorter canards and lower winglets.  We've got a fleet of them flying without - and they are just slightly mushier.

Klaus has proven to me how wonderful the trailing edge fences are on the Varieze - I hear he's advocating them for the Long EZ too, but didn't initially - due to less wing sweep.  Everyone who has the Varieze fences are very excited at the difference. 

Send me an e-mail and I'll get you the nearest good Varieze advisors.  The one thing we learned with a 100 member builders club in Los Angeles was not to be a loner.

Beagle

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on May 28, 2010, 01:47:53 AM

I have a set of Varieze plans and am considering building this as my second project ( built and flew Jabiru for 8 years )
I understand it would be easier to build a Long ez but the Varieze is closer to an almost single place aircraft and its what i would like to build
I have read quite a bit including some of the CP newsletters
I would like to build fairly close to standard  . But i have many questions and hope you will give me some of your accumulated wisdom
One of the things i dont like about the design is the wing spar attach system . The long ez is a much better more robust system IMHO
I am in the process of turning the original drawings into CAD . Without changing the geometry significantly it would be possible to attach the wing to the spar like the long ez
It would mean that i would have to move the root of the wing ( along BL 32 line ) 4.35 Inches ( 110.67 mm ) back ( chord remains standard just moves back )
The section remains standard the tip position remains standard ( no anhederal though ) The wing area remains the same
It means the wing leading edge sweep angle will change from 26 to 24 deg ( fairly small )
It will change the C of G point but maybe the engine can be moved forward to compensate .
Any ideas appreciated
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: go ez on May 28, 2010, 03:51:49 AM

I think what you are suggesting is very ambitious. The existing full CoG range is only 6" so moving the main wing aft 4" is 'changing the geometry significantly'.

Altering the wing position relative to the canard, fuselage & engine would need very significant aerodynamic design thought & testing. These are very safe aircraft and it would be a shame to risk losing that attribute.

Remember, even Mr Rutan, with his vast design expertise, computer design/simulation capability, financial resources & canard experience found he needed to modify (ie add area) SpaceShipOne' rear wing surfaces  to avoid unanticipated & undesired stalling characheristics that were only discovered during Mike Melville's test flights.

Structurally the box type Vari Eze main spar and wing spar & full width spar caps are very different to the Long Ez C shape main spar and  wing spar. It is certainly possible to incorporate the Long Ez spar design & overlap attach methodology. I've had some thoughts on this myself to eliminate the wing fittings and perhaps additionally extending the wing spar to full span as per the Long Ez design to enable fewer layups/ better use of UNI glass in the wings thus reducing aft weight.

Personally, I'd try to accommodate this within the existing aerodynamic platform.

Regards
Steve

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on May 28, 2010, 05:27:46 AM

Thanks Steve
I have had a careful look at the long Ez wing . Its only when you start to redraw in CAD that you can appreciate
how Burt Rutan could do this in his garage without a computer . Amazing stuff . And its very accurate .
Just to clarify what i had in mind.....
Only the root portion of the wing would move back 4+inches at the BL 32 line nothing else the wing area could remain the same
The main spar remains in exactly the same position although the tip is moved back about .75 inch ( 19mm )
The C section Long Ez spar looks lighter than the box section of the Varieze and does not have as much weight in the wing root fittings
Those wing root fittings mean the glass attached to them had to be much heavier to handle the loads at that point 
It would be interesting to calculate just how much weight goes backward if you take all that into account - i have not done that yet 
But i suspect its very little . My concern is the aerodynamics . The long Ez wing changed significantly , moving back and getting bigger so
the design can absorb some change .
My question is if the Cof G range could be made the same as original do you think moving the root back slightly would
have implications on the aerodynamics ?
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: go ez on May 28, 2010, 06:27:15 AM

I understand what you are saying (ie reducing the sweep) but the main wing centre of pressure will move back and possibly spanwise. The size/mass of the glass pads in the wing fittings etc are necessary to transfer the flight loads in the spar cap to/from the 1/4" bolts in the wing fitting and this mass  will be immaterial  compared to the overal mass of the a/c.

My point is indeed that the aerodynamics are the prime issue ie matching the revised centres of pressure of the two wings with the revised CoG of the a/c at all angles of attack.

You'd also need to check the CoL & CoG in relation to the position of the main gear attch & wheels so the a/c sits stabley on the ground & rotates at a reasonable speed.

Am certain the design can absorb change - main question is - will the change be nett beneficial?

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on May 28, 2010, 02:51:02 PM

I think you are correct
I know too little about the effects of moving the wing back . The collective information of canard aircraft of this type is essentially
understood by very few . Not a lot of written data - and the existing data is very questionable .
I guess i must try to find a way of mechanically attaching the wing like the long Ez and retain exactly the existing aerodynamics
Not because they are absolute but simply that i am unsure( at this point )  what changes would bring .
Anyway its an interesting topic .
Some things have been done and tested ( thats the beauty of the collective information  of the net )
The wing does not need anhedral
The main wing and canard can be set to the same incidence as the Long Ez
The strakes can be enlarged slightly without negative effect .

Title: Re: some Varieze questions - looking for info and suggestions
Post by: Tom on May 29, 2010, 09:34:06 AM

I wouldnt worry about the wing attachments,

The current VE wing fittings are fine,  the problem spawned out of a couple of old clunker aircraft
that had lived outside near the ocean for many years.

Burt also imposed the 2.4 G limit to deal with the dry layup on the spar on the aircraft with the corroded wing fittings....
completely unrelated.


Almost every weekend, I pull 5gs in my VE and NEVER once, NOT ONCE, have I ever been worried about the wings failing...  The factor of safety in the Rutan designs are HUGE!-- much higher than in most certified aircraft....

Bottom line is built it as per plans, and you wont be dissapointed... 

PS scrap the subaru.. that motor belongs on the road, not the air,,  we dont need another statistic.

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on May 30, 2010, 04:17:37 PM

Thanks for the reassurance
I am sure built correctly most of the Varieze's flying are as robust as yours
I have seen some destructive testing of a Varieze and one other issue is twisting
When the wing is loaded up starts to twists at the Strake wing joint
It makes sense if you see just what that joint has to take and the load paths to it
All i was looking at is the possibility of joining it like a Long Ez which from an engineering point
of view is a  much much less stressed joint with better loadpaths
The Varieze wing in that test failed at 7 Gs and the canard at 8
Actually at the inbord central spar section of the wing spar joint
If you want i can post that test ( PDF )again
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: Tom on May 30, 2010, 09:07:56 PM

Sure post it again,

the 7g failure of the wing seems a bit wonky..

As per the plans, the limit load is 5gs... which is VERY conservative....

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on May 30, 2010, 09:56:58 PM

RAF Varieze structural test ( PDF file )  is 600 KB but Max allowed is 300 KB for attachment
Any way around that ?
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: go ez on May 31, 2010, 04:30:43 AM

Try this link:

http://www.cozybuilders.org/Canard_Pusher/RAF_LE-Structural-Test.pdf

Regards
Steve

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on May 31, 2010, 02:48:16 PM

Thanks
Thats the one ... 
Interesting to note the 3.5G rating , based on this test
Thats partially my reason for finding another way of fixing the wing
Also the long ez system is easier to build with more repeatable results
I am sure most Varieze aircraft were built well so my attempt to find another way
is simply to my own personal decision
Another issue that came from this test is the wing twist issue
The original spar /wing joint is only 3.5 inches ( 89 mm ) from bolt center to bolt center
If you take the lever from the center of the spar to the center of the tip roughly 48 inches ( 1213mm )
Putting a pin at the leading edge of the root into the strake would help in keeping this area from twisting
In hindsight it easier to look back at the design and make smaller changes but i never lose sight of the elegance of the original design
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: go ez on June 01, 2010, 01:08:06 AM

I think Germany or perhaps Switzerland required that a structural anti twist pin be installed near the leading edge at the strake /wing interface - might have just been the Cozys or MkIV though.

I think I recall that Nat Puffer & Rutan both said it was unnecessary - which I guess with the reduced sweep compared to the VE is logical.

With the VE wing sweep, if you used the LEz type wing spar arrangement which is a C section rather than a torsionally stronger VE type box section then perhaps a leading edge pin might be prudent. It depends too on how much the wing and strake skins contribute to the overall stiffness.

The pin might need finally installing after the a/c has been flight tested so the ability to adjust the LEz wing incidence to compensate for small builder alighnment errors etc is not lost.

Regards
Steve

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on June 01, 2010, 01:55:30 AM

Good point
Maybe the pin is in the root of the wing and the recepticle can be bonded into the strake once the wing has been levelled etc
Most accident photos seem to suggest the strakes remain intact so the pin will be an intergral part of the wing attach
I have roughed out a sort of combination of box spar near the connecting point then back to a C section further towards the tip
The geometry seems to allow for that
The Varieze wing worked just fine without a spar all the way to the tip and from what i can see that should be ok
I still need to move the root back 2.4 Inches (60 mm) to make it work ( but i can move the seats forward 2 inches without changing the overall sizing )
I have done a rough calc and the change to the Cof G is very small
The aerodynamic change is small too if you consider the tip stays where it is
I have done some work on the main wing spar and it would be very close to the original and still have the hard points as the Long built it
So far it looks ok

Title: Re: some Varieze questions - looking for info and suggestions
Post by: Tom on June 01, 2010, 04:31:44 PM

I am an Aeronautical Engineer, and I can tell you the only thing that the "test to destruction" on the liked page proves is the the structure will fail....

It clearly states the wings were loaded to "increase the twist"....

Im not sure why anyone would waste their time doing this as the results will be useless.

If you think you are smarter than Burt Rutan,  give him a call, Im sure he will want to hire you. Otherwise trust his designs and analysis.
He does seem to know what he is doing.

-Tom

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on June 01, 2010, 09:10:59 PM

The point is that even Burt Rutan decided to change the wing attach system when the product became the Long Ez .
Is the Varieze inferior ? I don’t think so - just different . Products evolve . The car you drive today has seatbelts , ABS and airbags- they did not in 1976 .
Part of the reason aircraft /  space  market is changing is because of entrepreneurs like Burt and the hundreds of experimental builders out there .
Every time I read his Varieze manual and check the drawings  I am inspired by the beauty of his designs .
I am simply trying to look at the design for myself .
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: Joe Person on June 01, 2010, 11:24:46 PM

Just a few "FWIW's"

The VariEze wing attach configuration is very good, if built correctly.  The drawback is the requirement for correct overall fitting geometry and taper pin fit - Brock did a marvelous job on the fitting assemblies they built over the years.  Proper pin fit is essential to having a fitting assembly that is good for over 10 Gs.  One of the first things I did, back in the 80's, as part of beginning a VariEze, was to crunch some numbers, structures-wise (I are an engineer in the airplane biz myself).  I was not surprised to find a robust airframe.

The final version of of the Long-EZ wing configuration was the result of the conversion to an entire new wing planform, from the original Long-EZ prototype configuration.  As originally designed, the Long-EZ used VariEze wings (and fittings) on a wider centersection.  Flight testing revealed that this configuration was deficient in several ways, and after some iteration, Burt re-designed the main wing configuration for the Long-EZ, basing the wing attach configuration on the already designed & flying Defiant.

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on June 02, 2010, 03:25:47 PM

Thanks - i did some research on the Defiant
Some of my reasoning to change the wing attach on the Varieze .......
The wing attach fitting are hard to come by
They do not allow for any changes once fitted
The Defiant / long Ez system has proved reliable
Its actually easier to build
I am not quite there yet but i think its possible to build the Varieze
as it was designed ( aerodynamically ) and still change the wing attach
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: Bill James on June 02, 2010, 07:49:06 PM

Since getting hooked on this Eze thing in 1975, I believe this is the third or fourth “fix the VariEze wing attach” series that I have enjoyed following. Please don’t stop, this is a good one. I appreciate the serious and deliberate progression through good questions. I will just slide in a couple of fellow-traveler comments.
My bottom line early -- I got started late building the plane. My labor-intensive business and building the plane benefitted from my not being on the computer until after getting the VariEze flying. Combined with several other factors like "The List", the plane was in the air several years earlier than projected. My experience with the VariEze fittings has been positive. Like most long term VariEze types, I feel little inclination to counter anyone's opinion on the fittings, but dont mind stating mine.
Like you, I also researched the wing fittings. One example, having seen some early VariEze drawings of tapered ‘through-the fuselage’ sailplane-type wing plug-ins, I considered trying to design and build those myself for a ‘better’ design and quick attach. What could go wrong?   :)

I corresponded for several years with a VairEze driver that had flown his plane 2400 hours and never paid hangar rent. His plane was kept at home in an enclosed trailer and was taken to the airport on Fridays and assembled and then tied down in ideal weather, or pushed into a friend’s hangar overnignt, and then packed up and trailered home on Sundays. With the simple supports he had, removing or attaching the wings and canard was 20 minute process. A few years ago I heard he was over 4000 hours. This and other examples helped to wrap up my research, with the awareness that the VariEze fittings have some significant advantages, like no adjustments, and as Joe Person points out above, are just an excellent design. And like all of the other elements of the plane, they must be built correctly and maintained properly. 

While I was building I was strongly encouraged to put LongEZ wings and spar on  my VariEze, as several others had done.
We have been traveling to see grandkids lately and my wife has mentioned several things she would have liked the plane to have, like a toilet, and popcorn machine. I have written articles on the advantages of the LongEZ, but having a LongEZ would not have solved this   :)

I still enjoy chewing on the "law of thermodynamics" that was recently explained to me because it covers so much of life... You always lose, you never win, and you have to play.  I am enjoying finding the exceptions...

With 14 years and a thousand takeoffs and landings, including the three flights last weekend, I believe and have experienced that to have an operationally friendly plane there are many other fish to fry besides the wing fittings.  And lots of these things can be done after the plane is flying. If a guy is interested in flying   :)

You play the game and you take your best shot. Good luck. Many qualified engineers looked into this and decided not to go into the wing fitting business. And so far no non-engineers have made their fortune with this either. I got some good advice once, from someone you would know. "If you can make a living doing anything else besides trying to sell stuff to people that build their own airplanes, do it.
Oh, now i remember the thought that triggered this response - To get yourself up and flying you only need one set of fittings. There are probably still some out there.
Good building  :)

Title: Re: some Varieze questions - looking for info and suggestions
Post by: cloudman on June 02, 2010, 09:22:18 PM

I would be interested in hearing from other Varieze owners who have the plug-in wings that Fred Jiran built way back around the late 1970's. I understand that Burt did not like Fred making this wing/main spar attachment, but would like someone to confirm that this did actually take place. I have seen a few pictures on the internet of one rough looking installation.

I have no idea as to how many Variezes may be flying with this type of wing attachment.
Any info would be appreciated, since it seems like a valid way to attach.

Wayne Johnson Varieze N725EZ........flying since 1981

Title: Re: some Varieze questions - looking for info and suggestions
Post by: Joe Person on June 03, 2010, 10:28:34 AM

Mike Drew's VEZ (based at KPAE & diagonally from my hangar) has the Jiran wings & associated attach system.  Having examined the configuration in detail, I find it more complicated and heavier than the per-plans VEZ wing attach scheme.  The Jiran attach configuration is more difficult to install the wing solo, does also not allow incidence adjustment, and would entail a fair bit of re-design to blend this configuration with plans-built wings (Jiran wings are hollow, with inner and outer skins, vs. the full-core foam in a plans-built wing).  From an overall configuration standpoint, I can see why this configuration was not pursued.

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on June 03, 2010, 02:30:25 PM

I appreciate the suggestions and reflections from both Joe and yourself
I have read the articles and comments about your aircraft and were really useful to those like myself  trying to understand this aircraft type
My wish list is fairly simple - I want to build essentially a single seater with a possibility of a passenger from time to time .Burt's philosopy was a light, small ,simple aircraft
I think he achieved that with a basic Varieze. I have no intention to build other than for myself .
I will have more questions as i go along :)
Thanks
Flyoz
 

Title: Re: some Varieze questions - looking for info and suggestions
Post by: cloudman on June 03, 2010, 03:59:34 PM

Flyoz,
Your requirements for a single seat Varieze with an occassional passenger sounds like my Varieze with a C-85 with B & C starter.
I have pushed the max weight once in a while up to about 1125 #s. Flying to Jackpot , Nevada many years ago over the fourth of July with my 135 # WIB (wife in back) I limited my fuel to about two hours plus reserve of another hour or so. We had no trouble landing and taking off at Jackpot's approx 5000 ft altitude....by leaving in the morning before it got too hot.
So if you do not have to cruise much over 150mph TAS and burn 4 gallons per hour, the smaller C-85 is a good choice. My top TAS has varied with different props from around 175 to a bit over 180 mph
Flying south from the Seattle area to LA, I have stopped once for fuel at Red Bluff, CA. This is after being in the air around four hours. I am usually ready to get out for a break anyway, so stopping every 500 miles or so and adding 16 gallons of gas is usually appreciated.
Wayne Johnson .....Varieze N725EZ

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on June 04, 2010, 03:36:16 PM

Cloudman
Thanks for the info . It seems that your Varieze is just what you want .
The one overiding factor in my research is most people who have built a Varieze
with simplicity in mind have not been dissappointed . I am going to try to build as simply
as possible - i am progressing slowly - changing the drawings to CAD format and metric ( although i have retained the actual Inch dimensions )
Some would say redrawing in CAD is lost time but it allows me to understand the construction method more clearly i think .
What do you think of hand propping ?
Would you say an electric noselift is too much complication and a waste of time ?
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: cloudman on June 04, 2010, 08:05:18 PM

Flyoz,
I know there are those out there that would rather not have a starter and not lose the weight. It's their choice, but not mine.
When my starter or battery are giving me a problem, I always have the nose up against something solid eg. the closed hanger
door, the rubber tire on a vehicle, etc. Once when I did not do that was the time I forgot to pull the throttle back to idle after flooding the engine. If it had caught, my Varieze would have gone on its way across the airport. This has happened to others with bad
results. Also, if I happen to run the main tanks dry and the prop stops prior to my figuring things out, I have a starter to
get me going again even at low altitude. We are humans and humans sometimes make mistakes.
I expect that a good battery, B & C starter, cable, etc will weigh a minimum of forty pounds.
I flew a three place Cozy that really needed an electric nose lift.....but it did not have one. I used most of my strength to lift it after adding gas with the nose down. A Varieze does not need any powered lift, unless a person is unable to lift much weight at all.
Good luck with your project !
Wayne Johnson.........

Title: Re: some Varieze questions - looking for info and suggestions
Post by: Bill James on June 04, 2010, 08:42:51 PM

Hand propping. Hmmm.
Several months ago 4 yellow Piper Cubs stopped in here. Preparing to depart they did a mini-Blue Angles/Thunderbirds show. In unison they all chocked their planes, stood over the right tire with their left hand in the cockpit and propped the propeller with their right hands. They all started on the second pull and purred like kittens at what sounded like 100 rpm.
At Oshkosh a couple of years ago I stood by the throttle while Klaus started his dual LSI ignitioned VariEze. I think he said he said the plane had not run in 9 days. After his priming sequence it started on the second pull and purred at idle.
Approaching a thousand flights, I am still learning how to set up my 0-290 VariEze for the easiest start. For me this is mostly a priming thing. The bottom line from advisors is 3 prime strokes in winter and one in the summer, and then just start pulling. I will accept more advisors.
I have never seriously thought about adding a starter. If my engine would start within a dozen pulls, as it often does, I would never even think about a starter. The first time I started the engine it started on the first pull. If I am doing that airplane owner thing right, it should still start predictably most of the time. As with many things related to the VariEze, instead of building a DC-3 size Eze I use these elements as an incentive to be better.
Hand propping means that the pilot is very aware of the general engine condition, including compression. Working a little harder for our flight time, having awareness of good spark plugs, wires, mags, priming heads working (not stopped up), etc. is a more intimate thing.  I happen to be in a learning mode right now, recently starting the plane every day for about a week even if I didn’t fly. There is still some learning to do, along with checking some of the hardware. I have an impulse mag and one LSI electronic ignition with the red brick.
Since the LSI has a start bolt and a run bolt for the pickups, I have always expected it to be the significant player on hand starting rather than the Mag. During my present time of learning I found that the engine would start better on the one impulse mag with the LSI electronic ignition off. Once started, immediately after shut down with the switches, not the mixture cutoff, it started on the first pull with either the mag or EI or both. I am examining both sources of ignition for improvement.
In the past there have been a few episodes of trouble starting after landing and refueling for 20 minutes, maybe because of vapor lock. My best results there have been to leave the throttle at 1000 rpm and shut down with the switches, hoping for proper mixture still present and a one-prop start after refueling.
So much for positives and neutral opinions.
I think your comment might be more related to safety...?
I pay attention to those that have experience, good and bad. I try to be very deliberate. If I am interrupted during the preflight I start over. I also do the start the same way every time. On both main gear, I insert a quarter-inch steel rod through the strut and Matco brake disc, locking the brake. With the nose on the ground the plane won’t move at full throttle. I have never started with the throttle accidently left at full, but have moved the throttle to full with the steel pins in and it doesn’t move. The Matco disc already has three bolt holes drilled in them, I added 6 more, with no cracking or other issues.
I have observed folks hand prop until the engine pops and then shut off the mags and put the throttle open and the mixture off, and pull the prop backwards four revolutions, eight blades. This has resulted in an immediate start for me several times. This is also the place where we have to be very deliberate to re- set up the levers and switches to the correct positions.
On the other electric niceties, oh well, I have said enough here. Those might be the things I was thingking of that could be done after getting the plane in the air, if one still wants them.
Good building and flying-

Title: Re: some Varieze questions - looking for info and suggestions
Post by: cloudman on June 05, 2010, 08:53:15 PM

Flyoz and ............others
If you want to hand prop.....I don't recall if anyone has given instructions on the technique lately. Per Burt Rutan and watching him hand prop his Varieze years ago: First the prop is mounted to be on a compression stroke at the 10 o'clock-4 o'clock position. He stood to the right side of the prop, grabbed towards the tip at the 4 o'clock with the left hand and pulled upwards. This motion allowed him to step backwards and to the right away from the moving prop and air blast.

It works great if that's what you want to do. I doubt that there are few human pilots out there that have not made some sort of mental mistake at one point or another. I recall a Varieze pilot/builder and also Boeing engineer (if I recall correctly) hand propping his plane at Renton, WA airport some many years ago. His plane apparently had lots of throttle, got moving and crossed the active runway and crashied into a parked twin.

Having to hand prop is just one more way to potentially screw up !
I came close once......hand propping ...also once in a while I do not use my check list and forget a switch, setting the altimeter, etc.
I have been flying my Varieze for 29 years and still find new ways to mess up...It does seem that some of our new Varieze pilots are really having problems in keeping their plane in one piece.

Humans are not close to being perfect.....even those that think they are !!

Wayne Johnson

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on June 06, 2010, 03:23:50 AM

Thanks for a really useful discussion not only for myself but for others out there too .
Its adding to my notes .
Hand propping is an emotive issue i suppose (I have never hand propped an aircraft ).
I have never had an engine stop on me except on finals when the idle was not set right . I guess as a human you want that ability to actually be able to try and restart if you have to . But 40 Lbs is a lot of weight ... The idea of "dead" locking the brakes by putting holes in the discs is unique and practical so that resolves the runaway issue ( safety ) . Hand starting a pusher is much safer and hand cranking does give you some idea of the compression as discussed . I guess you have to live with the levels of simplicity you want . It breaks down into some basic issues .....
 If i hand start i have some control of who is close to the prop , i can see smoke or listen for some irregular noises
If the brakes are "dead" locked like Bill suggests then that resolves the runaway issue , makes hand propping less of an issue .
If the engine stops in flight i am unsure if it can be air started ? and leading on to that is the issue of fuel systems . I like the fuel system where the last available fuel is in the lower seat / tank so if you have fuel your engine should not stop . On long decents and only fuel in the seat/ sump tank is it possible to have too little fuel pressure ?
During hand propping is the fuel able to get to the engine when its on its nose ? Do you use or have a boost pump for the start sequence ?
I suppose the nosewheel is another item which has a higher chance of error . The nosewheel window goes some way to remind the pilot of its status . I guess you have to be careful with your checks but i understand the possibility of  human error. From what i can understand the mechanical nosewheel system is rugged provided the gearing is not actually used to hold the nosewheel but that it is capable of going fully over center for locking . The overcenter cam taking the landing loads .
What about fuel systems ? Do you place the filler caps so the aircraft can be on its nose during filling and still be filled to its max ? Some have a fuel drain close to the leading edge of the strake to check the fuel when the aircraft is in the nosedown position .
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: Joe Person on June 06, 2010, 11:52:29 AM

Hand propping is easy on an Eze.  I had to overcome a childhood fear of propellers (knew at 3 years old they went around fast and made scary noises...) to learn to prop the O-235 Long-EZ I helped build (first propped that one back in 1984, when I was 21).

The per-plans parking brake on the VariEze is a must, and works very well.  If you accidentally prop with a WOT, the airplane pirouettes to the left.  Outside indication that the parking brake is set is via a deflected left rudder.

Air starts are no problem - the typical prop on an O-200 Eze windmills down to around 55 KIAS.  With a stopped prop, mine takes about 125 KIAS or so to start turning over (Herztler Silver Bullet and stock O-200).

With the per-plans fuel system, you can run the mains bone dry - there is a 2-ish gallon header tank behind the passenger's head - this is reserve & starting fuel.  One can start on the mains, but they have to be on the fuller side to feed the carb in parked attitude.  Otherwise, I start on the header tank.  One of the beautys of the Eze fuel system is that it is gravity fed.  No pumps to crap out.  A seat-pan sump would require pumps - an electrical and a mechanical engine-driven pump.  More complexity.  More weight.

I have flown with both the crank-style NLG system (with ratchet lock, now in possession of my Aussie VEZ mate Greg Bakker), and the original push-pull system.  Properly rigged, the push pull is simpler & lighter.  Gary Hertzler has used this system from day one, as has Bob Evans (Cody, WY) - both of these gents' Ezes have several thousand hours.  I like my push-pull system just fine.  The per-plans throttle/gear/canopy warning system works very well also.

Fuel caps, per plans, allow you to fill almost-full, when parked nose-down.  Fuel drains at the LE root of the strakes are per-plans, and provide necessary "sumping" ability for the mains.

Title: Re: some Varieze questions - looking for info and suggestions
Post by: cloudman on June 06, 2010, 10:29:40 PM

Hi Flyoz,
Yes, if you want the lightest Varieze I would use the push-pull nose gear method. I had it installed already in my plane when Burt Rutan came out with the change. Reason? Only one fellow crashed and he would have survived but the metal tube went through his chest... so Burt decided to make the change. This was way back before 1980, so I do not recall any othe details but it was enough for me to make the change ....since at that time Burt knew best.

Yes, it is a good idea to start on the header tank when hand proping to make sure you are getting fuel to the engine. The only down side to that is that it increases your chance of taking off flying while still on the header tank. One would think that this should not normally happen, since the fuel handle selector is in the vertical position and it would surely be in the way of ones wrist......This is what I figured.........Wrong !! I only did it once. Ran the header tank dry while flying fairly low! Did I need the starter? No, I managed to figure what I had done quick enough while the prop was still turning and traveling probably 130 mph. I would suggest not talking to anyone while doing your final check. Also, when running low on the last several gallons in the main tanks, don't try a steep decent! Been there done that!

To be light as possible I would also eliminate the small lower winglets, if you already have them they along with a small metal angle make a nice pair of bookends. I figure I will have them in the rest home long after the plane and I have seperated ! When the lower winglets  are removed your induced drag should decrease and speed increase. All the fellows that want to go fast take them off. I took mine off also, but added LongEz style lower winglets instead. They provide me with a rock solid slow final approach at down to 75 mph indicated vs the  rocking wings with the originals at a very low speed. You may also want to experiment by trimming or rounding the main winglets in height like some have done to go faster. Read all the CSA newsletters for ideas. Also consider your desire to go as slow as possible during an off-airport landing.

My plane weighed 674 pounds empty (originally with the old heavy starter and using very heavy 1/0 cable per Burt's original plans).
Best advice to get a light weight plane is to build when it is warm or hot . It was around  95 degrees when my wings were layed up.
Regards, Wayne Johnson

Title: Re: some Varieze questions - looking for info and suggestions
Post by: go ez on June 07, 2010, 07:24:00 AM

Have a good read of this

http://www.ezarc.org/downloads/varieze_poh.pdf

Regards
Steve

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on June 07, 2010, 04:10:10 PM

Thanks Cloudman and all the others for your valid comments !
The plans i have are the original detail of the push pull nose gear , but it had no compression spring . I suppose it could be fitted( i like that aspect ) but i have decided to use the standard geared over center mechanism as the simplest and most reliable and incorporates the compression spring .
I am also going to eliminate the winglets as most have done ( i bet they make interesting bookends ! )Others have reduced lower winglets and i suppose thats a compromise between the long Ez types and no lower winglets .
Its good to know that it can be air started - that was the aspect of "no starter "which had me most concerned . Anyway to keep it simple i intend to go without a starter but you are right Cloudman - we are humans and do make mistakes .
I need to read more to understand the fuel system better ( i have been reading through the owners manual ).
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on June 09, 2010, 02:59:09 PM

Wing incedence and accuracy
I have been looking at the accuracy of the original wing root section . When  scanned from the original drawing templates
there are small inaccuracies - it must have been the original printing , also the root is printed in three sections on different sheets
I have read this very good article -  http://v2.ez.org/feature/F0502-1/F0502-1.htm ( thanks Bill ) .
You talk about changing the incedence to that of the Long Ez . The Original Varieze wing section is a modified GA(W)-1
and the templates only have the the waterline on them . The same is true for the long Ez templates - how do you modify the incedence ?
I have looked at the original GA(W)-1 ordinates to get the "zero " line but it is slightly different to the Varieze GA(W)-1 ( modified )
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: Bill James on June 09, 2010, 09:43:31 PM

The airfoils were not changed. The canard and wing have precisely the correct relationship to each other.
The canard and wing were built exactly to plans, as was the entire aircraft structure. The nose and forward strake installations are per LongEZ plans.
The wings are per plans. The main spar was built with the Brock spar fittings put on the opposite ends, upside down, with exactly the plans layups and materials on the spar.
The canard and main spar were both set up for installation on the fuselage per plans. They were both then adjusted to have one degree of additional incidence added to their angle of attack. That way, with a slightly higher AOA, when the canard and wing settle in in cruise where they are designed to, the fuselage attitude is slightly lower. –This is the adjustment that was made to the LongEZ installation, as I was told by a reputable person.
If you have studied the plans procedure for canard and main spar installation then you are familiar with the wooden template that sits on top of the canard and the approximately two foot long one that sits on the wing for setting the incidence with a level. The template is where the change is incorporated. The wings and canard are stock. With appropriate awareness and knowledge of what is involved in the plans installation, which takes some doing, then one can easily determine what would be involved to add one degree to their AOAs, canard and wings angle of incidence, relative to the fuselage. Very simple. If I can do it…
This involved a lot of head scratching for me and i wouldn't want to rob you of a similar, full experience by listing calculations and such. I have been very pleased with the results. I dont take changes lightly. Extra care and attention was involved. I am not naturally a detail person but am extremely aware of the results of complacency or lack of preparation or attention. I have mentioned that building and flying the plane has made me a better person. This is one of the layers on that onion, for me, involving using caution and getting good advice, becoming better at some things that are not natural or easy. I hope for you all to have as fulfilling of a journey and hope it is as demanding for you and requires your best in many areas of life to get your airplane brass ring. I encourage you to research and confirm everything i or anyone says.
After first flight, with the addition of a 3/16 shim to hold the left rudder out slightly, the plane flew straight and hands off on the second flight. The overall good alignment is mainly because in addition to the wooden template that sits on top of the wing - i added 6 foot wood trim extensions to the waterlines on the wing roots and tips, which allowed much more precise alignment of the wings when mated to the spar. When mating the center spar to the wings i put stanchions (metal fence poles with bases) around both wings. A string was run around the perimeter attached to the stanchions and using a home-made water level on the string all around, then the long wood trim strips on the wing waterlines were adjusted to set just on top of that perfectly level string. It’s interesting that with this string and water level setup the floor doesn’t need to be level  :)
The string and waterline trim pieces were also used later when installing the canard and spar to the fuselage. The wings were fully mounted to the main spar. This provided much more ability to achieve accuracy with three feet of waterline (trim) tool in front of and in back of the wings to run the string around, and using the simple and accurate water level. A similar, simpler process with long trim pieces was used when installing the winglets.
Enough. See you later. Clarification questions welcome and probably needed  :)

Title: Re: some Varieze questions - looking for info and suggestions
Post by: cloudman on June 10, 2010, 03:30:22 PM

Flyoz,
You mentioned the wing root section in three drawings. I recall that a fellow years back Xeroxed the airfoil for the canard...and built it using the copies. He later found out that the Xerox REDUCED the size of the airfoil ! I expect that scanners today do better, but........??

I would be CERTAIN that I have accurate templates for the airfoils. The wing has one for each end and one in the center. Someone was pre-cutting airfoils at one time which would be GREAT, otherwise it is a two person job. One has to be able to hotwire to the numbers and talk so the other person stays at the right number.

Good luck, Wayne Johnson

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on June 11, 2010, 03:44:30 AM

I have used the original templates drawings for the scans . I then printed my CAD files ( from those scans )  and placed the printed CAD file onto the original templates and they were accurate to the original templates so i beleive its as accurate as i will get them but the original templates had no measurements on them so i will have to rely on those original templates for size ( as many others must have ) .
Wing incedence - As i understand it the template waterlines are adjusted up 1 deg to increase the AOA and i am going to assume thats at the wing root attach center . Then all the other template waterlines are adjusted and checked back to the string line as you suggest . Extending the templates for accuracy makes good sense . I assume the wing tips will also rotate back 1 deg as well ?
Thanks for all  the feedback
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: Bill James on June 11, 2010, 12:04:40 PM

Flyoz
I assume you are talking about my wing incidence increase and that we are talking about the same thing  :)
No adjustments were made to waterlines, other than extending them with wood strips. The point of change here is the relationship between the attachment of the main spar to the aft fuselage, specifically within that 6x6x24 inch area where the spar is floxed to the fuselage sides. Again it has nothing to do with the shape of the wing airfoils.
Specifically on the center spar/wing installation to the fuselage - after following the plans to this point - The spar/wing assembly is inserted in the fuselage with the wings fully attached to the main spar, i.e. with the VariEze attach bolts tightened. Everything related to the wing and spar are per plans at this point. The exception would be my level no-anhedral wings, unrelated to this canard/wing incidence discussion.
The main spar may or may not have some wiggle room in the fuselage. The wooden wing template is set on top of the wing per plans to set the incidence. The wooden template is now modified, for example with a spacer, to establish a one degree higher AOA for the wing. I enjoyed pulling out my old textbooks here and conferring with patient advisors.
Here is where I waterleveled the wings for accuracy between them and the fuselage. If the canard is already hard-mounted it should also be installed fully for confirmation of the wing relationship.
This template spacer and slight main spar tilt is the only adjustment or modification involved in raising the main wing incidence. On mine the wing angle was almost right already. I used a few swipes with some coarse sandpaper inside the fuselage openings to provide room for the spar tilt.
Now the spar is floxed in place.
The canard is also unchanged, just installed slightly nose up using a modified canard template on top, retaining the plans relationship with the wings.
A few extraneous thoughts.
You are in extremely critical territory here, not the wing incidence thing, but building and flying your own airplane  :)
Everything about interpreting the plans and CPs should be a group discussion and plenty of productive mental wrestling matches.
For our discussion here with the wing incidence you are installing the wing the same plans way. It is possible that other VariEze spars have been installed very nearly at the same incidence as mine, only mine was done this way on purpose  :)   
In fact, with the fairly crude method of installing the attach fittings to the wings, any two or three main spars can have slightly different "tilts" to them between the wings, up and down, fore and aft.  That's why the fence and string setup when leveling the wings for the attachment (insertion) of the raw main spar between them is so useful. Wings and the spar are a matched set. A different wing may not match unless you are just extremely lucky.
  My wings are pretty well matched to each other. In fact they are very well matched based on flight characteristics. But while the wings are level and matched at the roots and tips, the spar is not "level". While both wings are “To Plans”, one wing attach assembly is about 1/8th inch higher than the other. This is totally normal, almost undetectable, insignificant and appropriate.
I have looked at numerous ezes that fly well, that from the front and rear critical examination show that the wings and canard are not “perfectly” aligned. It’s wonderful that they are flying well.
I will finally agree with many honest others as to having made as many mistakes on one side as the other  :)
While my plane could be cited as an example of rampant modifications, I feel the opposite, that the plane has followed the plans predominantly, and more significantly the intent of the Eze movement overall. The Ezes have been and are being honed by time. I know of no other airframe that allows so much of what Charles Lindberg spoke of, “Science, freedom, beauty, adventure: what more could you ask of life?”
We can all add our own passions to the list.
In agreement with Wayne’s prior comments on perfection, and the lack of it, I have been working on a note about the significance of the “Margin of Error” that seems to be the element of flying that we can actually influence or affect; practices like personal discipline, training, checklists, check flights, newsletters, etc that have evolved over the years. My efforts on capturing this in type have not matured adequately so far, particularly related to luck versus skill versus intelligence, but the significance of that margin is ever with me.
I hope working through this progression is helpful -- and a little unsettling, in the best possible way of course  :)

Lindberg's full comments containing the quote can be Googled.

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on June 11, 2010, 04:09:38 PM

Thanks Bill for the clarification your help appreciated
So as i understand it . Build the wings and centerspar as one unit  as close to the original templates as possible .Use entended templates and waterlevel and string system to set up the whole unit to the standard plans( but zero anhedral ) . This is where maximum accuracy is required. Then  the whole unit is is adjusted up 1 deg when it is fitted to the fuselage . Makes a lot of sense.
I have seen a system of templates where the original hot wire cut is made just slightly oversize and then the correct size templates fitted and sanded back to those  for increased accuracy . That could be done when the wings / mainspar is one unit for final accuracy .
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: Bill James on June 11, 2010, 07:58:09 PM

All good except the last statement. That is done to the raw foam before glassing the wings.
Keep on trucking along this journey of becoming an eze expert :)

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on June 18, 2010, 03:44:32 AM

More questions please
If you set the main wing up 1 deg do you do the same to the strakes (which seem from the plans to be symmetrical) ?
The fuel from the wings run into a sump tank under the passenger seat and i assume it has to have a boost pump for starting or long decents
because at those times the carb is lower than the tank - what about the possibility of the sump tank behind the back rest of the passenger seat
It would not be as low as the sump tank under the passengers legs ? its slightly ahead ( C of G )  of the header tank as the original plans depict ?
Thanks
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: go ez on June 18, 2010, 05:12:09 AM

I think you need to get very aquainted with the Canard Pusher newsletters ie read through them all.

http://www.cozybuilders.org/Canard_Pusher/

These update the plans -  in some cases in very significant areas - like plans errors, flight safety mandatory items and  the fuel system which changed from Version 1 to a gravity system with no pump and a fuselage header tank for starting on the nose and in long descents on low fuel.

The handbook I referred to in an earlier post mentioned the fuselage tank & operation of it.


Regards
Steve

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on June 19, 2010, 02:17:56 AM

Fair comment
I have read quite a few and looked at the plans - but not all ( its a continuous journey ! )
I suppose i was trying to see what other alternatives had been tried ( non RAF )
The incedent reports seem to suggest a higher number of failures because
The header tank was selected on start and left on or not used on long decents 
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: A. Bruce Hughes on June 19, 2010, 11:18:39 PM

Resist the temptation to use John Doe's or Mary Buildt's idea of a great mod.
I know very little about Variezes but I have an "almost finished" Longeze.
I tried a few changes and almost every one turned out to be a headache.
Even the ones that I did with RAF plans (landing light, internal bellhorn for
the rudders) created unexpected, time consuming, and unnecessary problems.
I my case, "little" changes extended the time to the point that I may not
finish it at all.    >:(

Bruce Hughes

 

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on July 12, 2010, 01:06:59 AM

From the Varieze manual the winglet trailing edge  "cant "angle is 90 Deg to the upper wing surface - i assume if you remove the anhederal that "cant " angle remains 90 deg ?
The lower winglet section template has a line on it - is that set parallel to the fuselage centerline ? I know there is a template for setting that .
I dont have Page A8 as called for in the manual and that has all the winglet templates - anyone have a copy of that page ?
Flyoz

Title: Re: some Varieze questions - looking for info and suggestions
Post by: Bill James on July 12, 2010, 05:40:35 PM

“Are you talking to me...??!!”

Sorry, I am just remembering when we were holding around Green Lake at Osh, on the entry where you don’t talk and just listen,  with a pilot shouting out "Are you talking to me...??!!” every time the controller cleared someone in past Fisk   :)
If you are not talking to me, and if not I will gladly relinquish the controls to someone else with a VairEze with no anhedral... You know it would have been nice if someone would have mentioned to me there was supposed to be anhedral in there…      :)  :)
Anyway, my wings and winglet attachment are pure stock    :)  :)  :)

Title: Re: some Varieze questions - looking for info and suggestions
Post by: flyoz on July 12, 2010, 06:43:53 PM

Sorry Bill
The question was two fold i suppose
Thanks - so your winglets are built as the manual 90 Deg to the upper surface of the wing and used all the standard templates on Page A8
My following question is to yourself and anyone else - does anyone have a copy  of page A8 and those templates even if they are not to scale ?
Flyoz