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62
Hangar Flying / Re: some Varieze questions - looking for info and suggestions
« 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
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
63
Hangar Flying / Re: some Varieze questions - looking for info and suggestions
« on: May 31, 2010, 04:30:43 AM »64
Hangar Flying / Re: some Varieze questions - looking for info and suggestions
« 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?
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?
65
Hangar Flying / Re: some Varieze questions - looking for info and suggestions
« 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
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
66
Hangar Flying / Re: Voids under wing skin
« on: February 02, 2010, 07:00:51 AM »
I agree that epoxy would be right if the delamination was glass on glass ie say wing skin over spar cap but in that situation I think it would be essential to have a very close look at the cause.
However since all layups on foam are preceded by a micro / epoxy slurry to ensure good bonding, it doesnt seem unreasonable to use the same for re-establishing that bond.
It was suggested by Rutan for repairing the landing brake after it was found that the urethane near the reinforcing wood hard point was breaking up due to movement/working.
ie CP43 p4
"If you have already built your landing brake or are already flying, an
appropriate repair/reinforcement is as follows: drill several 1/16" or
1/8" diameter holes through the skin below (or aft) of LB19 plywood
insert. Inject pure epoxy or a very liquid slurry into each hole,
forcing the slurry/epoxy into the damaged urethane foam. When this
cures it will greatly stiffen this area of damaged foam. Remove the
LB18 brackets and layup 4 plies of UND over the plywood insert and down
the inside skin of the landing brake as shown."
I agree that pure epoxy would do the job too though, if a little heavier and I agree the plans & CP notes call out pure epoxy. Thanks for pointing that out.
However since all layups on foam are preceded by a micro / epoxy slurry to ensure good bonding, it doesnt seem unreasonable to use the same for re-establishing that bond.
It was suggested by Rutan for repairing the landing brake after it was found that the urethane near the reinforcing wood hard point was breaking up due to movement/working.
ie CP43 p4
"If you have already built your landing brake or are already flying, an
appropriate repair/reinforcement is as follows: drill several 1/16" or
1/8" diameter holes through the skin below (or aft) of LB19 plywood
insert. Inject pure epoxy or a very liquid slurry into each hole,
forcing the slurry/epoxy into the damaged urethane foam. When this
cures it will greatly stiffen this area of damaged foam. Remove the
LB18 brackets and layup 4 plies of UND over the plywood insert and down
the inside skin of the landing brake as shown."
I agree that pure epoxy would do the job too though, if a little heavier and I agree the plans & CP notes call out pure epoxy. Thanks for pointing that out.
67
Hangar Flying / Re: some Varieze questions - looking for info and suggestions
« 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
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
68
Hangar Flying / Re: Voids under wing skin
« on: February 01, 2010, 03:41:44 AM »
Depends on whether you have voids (how do you know?) or delaminations where the skin has separated from the core.
If the latter, drill a couple of holes in the skin and inject microslurry (mixed epoxy & microballoons to a thin cream consistency) under the skin then apply a release film (cling film / saran wrap) over it then weight down (some use vacuum techniques) sufficient to get the skin to contact the foam. It is worth removing the weight / release film after the initial application to ensure that inevitable ( and preferable) excess slurry is extruded from the holes and then wiped away from the skin -then re-apply the release film & weight.
Leave to cure for 48hrs depending on temeperature.
If voids are truely present, you need to cut away the skin and insert a foam plug with micro, re-shape and re-skin with adequate overlap onto surrounding bare glass to ensure strength & rigidity is retained.
Some areas on the airframe are much more critical if damaged than others so you also need to be aware of the implications of a repair.
Simple if you know how of course - if you don't, get help - ideally by joining CSA and getting a local buddy to help/advise.
Regards
Steve
If the latter, drill a couple of holes in the skin and inject microslurry (mixed epoxy & microballoons to a thin cream consistency) under the skin then apply a release film (cling film / saran wrap) over it then weight down (some use vacuum techniques) sufficient to get the skin to contact the foam. It is worth removing the weight / release film after the initial application to ensure that inevitable ( and preferable) excess slurry is extruded from the holes and then wiped away from the skin -then re-apply the release film & weight.
Leave to cure for 48hrs depending on temeperature.
If voids are truely present, you need to cut away the skin and insert a foam plug with micro, re-shape and re-skin with adequate overlap onto surrounding bare glass to ensure strength & rigidity is retained.
Some areas on the airframe are much more critical if damaged than others so you also need to be aware of the implications of a repair.
Simple if you know how of course - if you don't, get help - ideally by joining CSA and getting a local buddy to help/advise.
Regards
Steve
69
Hangar Flying / Re: Varieze N5WZ is gone.......Jim "Too Tall" Hall
« on: December 03, 2009, 03:52:54 PM »
Hi sorry to hear of your loss.
Ref the VE parts -are the wing fittings still ok - do you want to sell them?
Thanks
Steve
Ref the VE parts -are the wing fittings still ok - do you want to sell them?
Thanks
Steve
70
For Sale/Wanted / Re: Collection of parts and unused, unregistered plans (S/N 21) for a Vari-Eze
« on: October 31, 2009, 01:32:26 PM »
I too am interested - please contact me on stephendbrown at btconnect.com - change at to @ & remove spaces.
Thanks
Steve
Thanks
Steve
71
Hangar Flying / Re: long ez plans
« on: September 11, 2009, 04:19:08 AM »
Ref foam life - depends if it has been kept in the dry & dark - UV light damages it. You can usually easily tell if it is crumbly , discoloured on the surface compared to the core colour etc. All things being equal ref storage, light shielding etc., PVC is most robust, then styrofoam, and lastly urethane being the least age resistant.
Ref glass contamination
See CP 35 page 7 ie
Quote :
'Caution: Small strips of the cutting surface may contaminate your
cloth, so inspect carefully and change your cutting surface often.
Glass cloth must be kept absolutely clean. If it is ever exposed to
water it must be discarded.'
End quote
As Bill highlights, I understand the individial glass strands have an invisible coating on them, both to protect them from airborne contaminants from etching the fibres and to aid wetting out the cloth with resin. Water contamination washes this coating away & leaves the individual glass strands exposed to weakening through air etching & creation of stress raisers.
I have some previously water contaminated glass cloth that I use soley for non structural fairings, auto parts or moulds and you can tear it with your bare hands!!!
And get access to the CP notes - totally & utterly as essential as the plans.
Ideally hard copies or at least
http://www.cozybuilders.org/Canard_Pusher/CPs_1_to_82_Sections.txt
Regards
Steve
Ref glass contamination
See CP 35 page 7 ie
Quote :
'Caution: Small strips of the cutting surface may contaminate your
cloth, so inspect carefully and change your cutting surface often.
Glass cloth must be kept absolutely clean. If it is ever exposed to
water it must be discarded.'
End quote
As Bill highlights, I understand the individial glass strands have an invisible coating on them, both to protect them from airborne contaminants from etching the fibres and to aid wetting out the cloth with resin. Water contamination washes this coating away & leaves the individual glass strands exposed to weakening through air etching & creation of stress raisers.
I have some previously water contaminated glass cloth that I use soley for non structural fairings, auto parts or moulds and you can tear it with your bare hands!!!
And get access to the CP notes - totally & utterly as essential as the plans.
Ideally hard copies or at least
http://www.cozybuilders.org/Canard_Pusher/CPs_1_to_82_Sections.txt
Regards
Steve
72
Hangar Flying / Re: nose wheel
« on: December 17, 2008, 04:16:36 PM »
Get one of these - far better & beefier than the std Brock wheel which breaks.
Unbelievable value - includes the bearings - all you then need is the spacers & a long AN4 bolt.
http://www.wicksaircraft.com/catalog/product_detail.php/pid=14909~subid=10583/index.html
Regards
Steve
Unbelievable value - includes the bearings - all you then need is the spacers & a long AN4 bolt.
http://www.wicksaircraft.com/catalog/product_detail.php/pid=14909~subid=10583/index.html
Regards
Steve
73
For Sale/Wanted / Re: Shimmy Damper for --Vari-Long-Cozy-E-Racer
« on: November 20, 2008, 10:26:25 AM »
After removing the pin, I heated my fork/shaft in the oven and it popped out easily with a few taps.
Similarly I heated the fork in the oven & put the new shaft in the freezer and they assembled by gloved hand - no force needed at all. Easy.
Create a drill point centre on the shaft by a few max size drill turns in the roll pin hole, then drill out with a smaller drill & progressively open out the hole to the correct roll pin size. This way you avoid overdrilling the softer ali fork hole & making the roll pin loose.
I agree that you do each side separately.
Similarly I heated the fork in the oven & put the new shaft in the freezer and they assembled by gloved hand - no force needed at all. Easy.
Create a drill point centre on the shaft by a few max size drill turns in the roll pin hole, then drill out with a smaller drill & progressively open out the hole to the correct roll pin size. This way you avoid overdrilling the softer ali fork hole & making the roll pin loose.
I agree that you do each side separately.
74
Hangar Flying / Re: Aircraft Designator
« on: October 31, 2008, 10:23:38 AM »
http://www.icao.int/anb/ais/8643/Foreword_english.pdf
http://www.icao.int/anb/ais/8643/
Seems reasonably official.
Regards
Steve
http://www.icao.int/anb/ais/8643/
Seems reasonably official.
Regards
Steve
75
Hangar Flying / Re: Aircraft Designator
« on: October 30, 2008, 03:57:07 PM »
On flightplans I use VEZE for my VariEze and I think LGZE is for the Long Ez
ie
Manufacturer Model Type Designator Description Engine Type Engine Count WTC Photo
RUTAN Ares ARES Landplane Jet 1 L -
RUTAN 32 VariViggen VVIG Landplane Piston 1 L -
RUTAN 33 VariEze VEZE Landplane Piston 1 L -
RUTAN 40 Defiant DEFI Landplane Piston 2 L -
RUTAN 61 Long-EZ LGEZ Landplane Piston 1 L
RUTAN 77 Solitaire SOLI Landplane Piston 1 L -
RUTAN 151 Ares ARES Landplane Jet 1 L -
RUTAN 202 Boomerang BOOM Landplane Piston 2 L -
RUTAN 27 VariViggen VVIG Landplane Piston 1 L -
RUTAN 318 White Knight WHKN Landplane Jet 2 M -
RUTAN White Knight WHKN Landplane Jet 2 M -
RUTAN Boomerang BOOM Landplane Piston 2 L -
RUTAN Cozy COZY Landplane Piston 1 L -
RUTAN Defiant DEFI Landplane Piston 2 L -
RUTAN Long-EZ LGEZ Landplane Piston 1 L
RUTAN Proteus PRTS Landplane Jet 2 L -
RUTAN Solitaire SOLI Landplane Piston 1 L -
RUTAN VariEze VEZE Landplane Piston 1 L -
RUTAN VariViggen VVIG Landplane Piston 1 L -
RUTAN 281 Proteus PRTS Landplane Jet 2 L -
ie
Manufacturer Model Type Designator Description Engine Type Engine Count WTC Photo
RUTAN Ares ARES Landplane Jet 1 L -
RUTAN 32 VariViggen VVIG Landplane Piston 1 L -
RUTAN 33 VariEze VEZE Landplane Piston 1 L -
RUTAN 40 Defiant DEFI Landplane Piston 2 L -
RUTAN 61 Long-EZ LGEZ Landplane Piston 1 L
RUTAN 77 Solitaire SOLI Landplane Piston 1 L -
RUTAN 151 Ares ARES Landplane Jet 1 L -
RUTAN 202 Boomerang BOOM Landplane Piston 2 L -
RUTAN 27 VariViggen VVIG Landplane Piston 1 L -
RUTAN 318 White Knight WHKN Landplane Jet 2 M -
RUTAN White Knight WHKN Landplane Jet 2 M -
RUTAN Boomerang BOOM Landplane Piston 2 L -
RUTAN Cozy COZY Landplane Piston 1 L -
RUTAN Defiant DEFI Landplane Piston 2 L -
RUTAN Long-EZ LGEZ Landplane Piston 1 L
RUTAN Proteus PRTS Landplane Jet 2 L -
RUTAN Solitaire SOLI Landplane Piston 1 L -
RUTAN VariEze VEZE Landplane Piston 1 L -
RUTAN VariViggen VVIG Landplane Piston 1 L -
RUTAN 281 Proteus PRTS Landplane Jet 2 L -