Author Topic: some Varieze questions - looking for info and suggestions  (Read 34711 times)

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Offline Joe Person

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Re: some Varieze questions - looking for info and suggestions
« Reply #30 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.



Joe Person
VariEze N79JN
Cozy #879 Under Construction
EAA Tech Counselor 4418
Bothell, WA (KPAE)

Offline cloudman

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Re: some Varieze questions - looking for info and suggestions
« Reply #31 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

Offline go ez

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Re: some Varieze questions - looking for info and suggestions
« Reply #32 on: June 07, 2010, 07:24:00 AM »
Have a good read of this

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

Regards
Steve

Offline flyoz

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Re: some Varieze questions - looking for info and suggestions
« Reply #33 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

Offline flyoz

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Re: some Varieze questions - looking for info and suggestions
« Reply #34 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

Offline Bill James

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Re: some Varieze questions - looking for info and suggestions
« Reply #35 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  :)
« Last Edit: June 10, 2010, 02:02:16 PM by Bill James »
Bill James, Fort Worth VariEze N95BJ
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Offline cloudman

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Re: some Varieze questions - looking for info and suggestions
« Reply #36 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

Offline flyoz

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Re: some Varieze questions - looking for info and suggestions
« Reply #37 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
« Last Edit: June 11, 2010, 12:15:43 PM by Bill James »

Offline Bill James

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Re: some Varieze questions - looking for info and suggestions
« Reply #38 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.
« Last Edit: June 11, 2010, 01:41:48 PM by Bill James »
Bill James, Fort Worth VariEze N95BJ
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Offline flyoz

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Re: some Varieze questions - looking for info and suggestions
« Reply #39 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

Offline Bill James

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Re: some Varieze questions - looking for info and suggestions
« Reply #40 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 :)
« Last Edit: June 12, 2010, 06:22:48 AM by Bill James »
Bill James, Fort Worth VariEze N95BJ
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There was supposed to be anhedral?
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Offline flyoz

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Re: some Varieze questions - looking for info and suggestions
« Reply #41 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

Offline go ez

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Re: some Varieze questions - looking for info and suggestions
« Reply #42 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

Offline flyoz

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Re: some Varieze questions - looking for info and suggestions
« Reply #43 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

Offline A. Bruce Hughes

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Re: some Varieze questions - looking for info and suggestions
« Reply #44 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