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Hi all,

This looks like a good forum to learn about my varieze. Recently brought it over from USA to Australia where I live. One issue with the a/c is that max. indicated cruise speed is 120 kts and the 0-200 continental revs at only 2400 rpm. Adjusted the throttle so the carby opens up more, but no improvement. We at the club think the pich of the prop. is too high. It is 57 " dia but does not have any pich info. The engine has good compression with only 163 hours.

Is there anything else I need to check before changing props? Also, some of the tapered wing pins are flush or slightly below the surface. They are .990" max dia. Made one up out of high tensile steel 1.00" dia and it sits ok. Though someone mentioned if the high tensile steel has enough sheer strength. Can you buy those pins in different sizes?

 

Any comments appreciated

Thanks,

Norm

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Hi all,

This looks like a good forum to learn about my varieze. Recently brought it over from USA to Australia where I live. One issue with the a/c is that max. indicated cruise speed is 120 kts and the 0-200 continental revs at only 2400 rpm. Adjusted the throttle so the carby opens up more, but no improvement. We at the club think the pich of the prop. is too high. It is 57 " dia but does not have any pich info. The engine has good compression with only 163 hours.

Is there anything else I need to check before changing props? Also, some of the tapered wing pins are flush or slightly below the surface. They are .990" max dia. Made one up out of high tensile steel 1.00" dia and it sits ok. Though someone mentioned if the high tensile steel has enough sheer strength. Can you buy those pins in different sizes?

Any comments appreciated

Thanks,

Norm

sounds like you may have to much pitch. try flying level at about 5000 ft. put it in a slight dive and let the speed build up then slowly come back to level and see what speed it will hold. on the small engines it is sometimes hard to get up to top speed when flying level. what is the top static RPM you can get? you should be getting 2300 to 2500 static RPM. Does the plane have wheel pants installed and what size tires, these can make a big difference on a O-200 varieze. did you remember to retract the nose gear ?

the taper pins are on longer available. the one you made should be fine. if you make the pin out of 4130 or similar steel you will tear the wings off long before you will shear those pins.

Evolultion Eze RG -a two place side by side-200 Knots on 200 HP. A&P / pilot for over 30 years

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Hi all,

This looks like a good forum to learn about my varieze. Recently brought it over from USA to Australia where I live. One issue with the a/c is that max. indicated cruise speed is 120 kts and the 0-200 continental revs at only 2400 rpm. Adjusted the throttle so the carby opens up more, but no improvement. We at the club think the pich of the prop. is too high. It is 57 " dia but does not have any pich info. The engine has good compression with only 163 hours.

Is there anything else I need to check before changing props? Also, some of the tapered wing pins are flush or slightly below the surface. They are .990" max dia. Made one up out of high tensile steel 1.00" dia and it sits ok. Though someone mentioned if the high tensile steel has enough sheer strength. Can you buy those pins in different sizes?

 

Any comments appreciated

Thanks,

Norm

G'Day Norm,

 

I agree with Lynn.

 

- What is your static RPM, nil wind?

- Did you retract your nose gear, and speedbrake?

 

Static should identify a poor prop match (seems likely) or engine issue. I would be looking for 2400 static (min) which I am certain you wont get if you are topping out at that value. I would also static test another prop, with known O-200 static. If the prop is the issue, my recommendation is replace it with a Hertzler silver bullet prop or similar. I static 2500RPM.

Cheers,

 

Wayne Blackler

IO-360 Long EZ

VH-WEZ (N360WZ)

Melbourne, AUSTRALIA

http://v2.ez.org/feature/F0411-1/F0411-1.htm

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Thanks all for replying,

My static rpm is 2300. At 90 kt climb it is 2400 and at cruise, wheel and brake up full throttle, still around 2400. I assume you should be able to red line the rpm at 2750 full throttle. At 2400 rpm the engine would not be producing full power. Where would I get a silver bullet prop or similar in Australia, Longez. Lynn, the a/c has wheel pants and what looks like standard tyres. I'll make the rest of the pins with my standard grade of 8.something high tensile steel. The walls will be thicker as I will make a smaller hole in the center which fits my socket. Phil, if I am passed by a Beech Musketeer, I'll know who it is. But you won't get full marks for navigation.

 

Thanks,

Norm

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Hi all again,

I just phoned the previous owner of my Varieze and he said that the engine would sometimes drop from 2800 rpm on cruise to 2400rpm. He would put the throttle to idle and then back again to regain rpm. I've done 10 hrs flying and never seen the rpm above 2400. On the day he showed me the a/c it was running ok. He replaced the carby before, but made no difference and so put the old one back. Looks like I am the one who will have to solve the problem. Runs smoothly all the time from idle to full power so faulty lead would probably be out. Can mags do that? Any fault finding guys out there with ideas.

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Would guess the 120 kts is confirmed by GPS or wingman? Am sure you have determined proper mixture operation but didn't see you mention it. At 8000 density altitude you can put the throttle open and reduce the mixture some until the RPM peaks or the engine starts to run slightly rougher. If the max rpm in that area is still around 2400 rpm I agree the prop pitch is probably too coarse. Whatever the outcome, would be good to record these numbers for later comparison.

Some other things you have surely already done:

No go without working canopy catch and gear/canopy warning system.

With the elevators an inch or so low, confirm the speed at which the nose wheel lifts off.

Determine minimum speed (at altitude, per POH, all safety issues accomplished). It has been said and I agree that that speed plus 22 mph equals “minimum” approach speed where the rate of descent can be routinely arrested. When I fly the approach at that speed it is often useful to add a touch of throttle just before touchdown. Probably no issue with a 57 inch prop.

Can just imagine the fun you must be having. Congrats.

 

Just saw your note above. Am sure others have better troubleshooting advise but the filters come to mind, carb and fuel. I have found it interesting and valuable to have several A&Ps touch the engine during the annual, I always learn something. One similar thing i experienced was a bad plug that was firing, but under pressure testing showed an orange spark instead of blue. Good hunting.

Bill James, Fort Worth VariEze

Downdraft Plenums

Quickcowls

There was supposed to be Anhedral???

http://www.ezchronicles.com/blogger.html

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Thanks Bill,

First I will check the fuel flow according to the 1977 varieze manual. There is a knob attached to the fuel filter via a cable instructing me to pull it to clean the filter. Nothing visibly happened. Is fuel supposed to gush out and clean it or is it all badly clogged? Is there more than one fuel filter. Auto carbies which I've worked on a lot, used to have a small round gauze where the fuel enters the bowl as well as the in line filter.

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They say the airplane talks to you. Discretion is the better part of valor with a gremlin in there moving the rpm at will :) Hopefully something simple. Am not familiar with the filter cleaning cable. Accomplish an inspection with someone familiar with the 0-200 and/or aircraft induction. Several sets of eyes help here. One aspect of the carb filter is to confirm that it is not deteriorated or installed such a way that it is hanging by a thread and could get sucked into the carb. Good to stay alert and over the airport until the cause is determined and cured.

We did find a shorting spark plug harness by running the engine at night with the cowl off. The shorting plug caused a surprisingly large rpm drop. BTW, when working on or preflighting the aircraft, at every instance that I move through the prop arc I stop and say “Yes the engine is stopped and yes it is safe and yes I intend to move past this stationary propeller”. I am probably saying all this to Chuck Yeager’s instructor, but comments are well intended :)

Bill James, Fort Worth VariEze

Downdraft Plenums

Quickcowls

There was supposed to be Anhedral???

http://www.ezchronicles.com/blogger.html

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Thanks Bill,

First I will check the fuel flow according to the 1977 varieze manual. There is a knob attached to the fuel filter via a cable instructing me to pull it to clean the filter. Nothing visibly happened. Is fuel supposed to gush out and clean it or is it all badly clogged? Is there more than one fuel filter. Auto carbies which I've worked on a lot, used to have a small round gauze where the fuel enters the bowl as well as the in line filter.

Are you talking about the gascolator? The knob on the bottom of the gascolator has safety wire in it that has to be cut off. Then you back the knob off to let the bowl drop. There is a fine mesh filter inside.

 

With the motor off, go to full throttle. Check that full throttle is actually happening on the carb.

 

Your airspeed could be incorrect, your rpm could be incorrect. You will need to check these.

 

The best thing is to go grab an A&P to check out your set up. Next, grab some good aircraft engine books and study the Varieze engine install plans. You will need to rely on the A&P to help you out until you build up your aircraft engine and systems skills.

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Thanks all for the info. Tomorrow I will go down to the a/c with my sledge hammer, power saw and other aviation tools to sort this out. Seriously, Chuck Yaeger attributed his survival to knowing the systems on his aircraft and probably a lot of quick thinking under pressure. I'll have to do the same. Yes, hand propping has it's hazards as we had one runaway a/c in the club. The last thing I check before meshing my body with the prop is the throttle position. All other settings can be off and no disaster. My new wing pins are being made in comfort knowing that my wings will rip off before the pins sheer. All this and more I learned in a few days on the forum.

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Thanks all for the info. Tomorrow I will go down to the a/c with my sledge hammer, power saw and other aviation tools to sort this out. Seriously, Chuck Yaeger attributed his survival to knowing the systems on his aircraft and probably a lot of quick thinking under pressure. I'll have to do the same. Yes, hand propping has it's hazards as we had one runaway a/c in the club. The last thing I check before meshing my body with the prop is the throttle position. All other settings can be off and no disaster. My new wing pins are being made in comfort knowing that my wings will rip off before the pins sheer. All this and more I learned in a few days on the forum.

Does your carb air intake system have the standard 2 1/2 inch ducting? The scat or sceet type can be sucked closed if it gets old and tired. The sceet may look good on the outside, but loose on the inside.

WTJohnson

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Observations:

 

1. Sounds like you have a gascolator that uses a pull cable, similar to that on a Cessna 150 (?)

 

2. SCEET/CEET should NEVER be used for induction hose - the inner layer can separate from the rest of the tubing, and cause an engine shutdown.

 

3. Make sure your taper pins for the wing attach are lapped into the bores of the fittings (with the wings installed and jigged so as not to move). Lack of uniform contact in the bores here can result in sparcap overloads at lower g loads that one would expect (e.g. as low as 2.8 gs). Pins are 4130, heat treated to 125 ksi, FWIW, per plans.

 

4. A Silver Bullet on a VEZ with an O-200 will not yield any "magic" results unless you have a good O-200 (i.e. capable of developing rated HP) and a clean airplane (drag-wise). I fly a Silver Bullet on my O-200 Eze (speaking from experience here).

 

5. A static RPM of 2300 is not bad at all - you should, as noted (with all other parameters running "100%") be able to get 2750 wide-open, down low.

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Hi MacGyver,

Those wing pins are more complicated than I thought. Maybe each wing pin has to be matched to it's position on the wing and logged. Howabout I smear blue dye on the wing taper, insert the pin, and see if there is a uniform transfer of dye to the pin. Then file the pin to a different taper to match, if required. With regard to the hardness of the pin, the pin is easier to replace than the wing fitting and should be softer and not hardened. Replace them when they show wear.

Will dismantle and clean out the fuel system. The plane was built in 1982 and flown only 300 and a bit hours. Gunk from dried up fuel probably has collected.

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Norm,

 

The pins' fit in the bores can be checked with engineering/Prussian blue. They need to have a very well matched fit. As for filing, I hope you intend to use a lathe.

 

When Ken Brock made the fittings (the original supplier), the pins were matched to the tapered reamer that made the tapered bore in the entire fitting assembly stack-up. This ensured a very good match overall.

 

The problem with poorly-fitting pins lies with an end-result of one of the .125 plates on the centersection spar picking up more of the load that the other. Example: If the inner plate picks up load before the outer plate does, you induce a bending moment in the glass sparcap itself. With the sparcap reacting this moment, worst-case, you can fail the sparcap in bending before you ever get to design max g.

 

As for pin hardness, per plans the pins are supposed to be heat treated to 125 ksi. You do not want to begin any distortion of the pins at lower loads.

 

Stock pins were 4130, heat treated to 125 ksi, with a cadmium plating. By design, included angle was supposed to be 10 degrees. Generally, Brock-manufactured pins dialed in between 9.2 and 9.7 degrees or so (based on measurements I made on an optical comparator on 4 different sets of Brock pins, over sevral years).

 

Properly manufactured (correct materials and such), and with correct geometry/fit, the VEZ wing fitting is very robust and will give a long service life. You should not have to be concerned with "pins wearing out". Again, all things being correct, the pins will not wear out, nor will the bores. Gerry Gardiner, of Sheridan, WY, has a 4500+ hour VariEze built in the 1970s. He trailers his Eze to and from the airport (since day-one, effectively), for every flying session, which entails wing removal/installation far beyond what almost all of the operational VariEze fleet experiences.

 

Torque for the through-bolts is 36 - 40 inch-pounds, no more. If you have to use more torque to snug things up, something is not right. Refer to CP 61 (repeated below) for information on VEZ taper pins, and what can happen if the wing/centersection interface is not rendered correctly.

 

I'd plan on going through the airplane with a fine-tooth comb. One of the most important aspect of these types of airplanes is that each is unique. Some are built/integrated better than others. Be cautious, and be careful whom you rely on for help online.

 

Feel free to give me a holler anytime - ezejoe@comcast.net.

 

Meantime, read the excerpt from CP 61 (below), and go have an Emu beer for me...

 

Cheers,

 

-Joe Person

EAA Tech Counselor 4418

VariEze N79JN

Bothell, WA (KPAE)

 

 

CP 61 - Taper Pins

 

A VariEze crashed in Southern California recently and both occupants were killed. There was one eye witness who reported observing the VariEze performing some aerobatic maneuvers before it abruptly lost power and fell to the surface of a wet salt pan. The VariEze hit the surface essentially flat with little or no forward motion and was inverted. These very unusual circumstances called for a full investigation. Two representatives from RAF assisted the FAA in trying to determine what might have caused this tragedy. The investigation team was forced to use a helicopter to examine the crash site since it was not possible to walk across the muddy salt pan which was many feet deep in places.

 

It was obvious from 300 feet above the crash site that the VariEze had impacted inverted, with little or no forward or lateral velocity. This was evidenced by the mud splash marks radiating out from the center of impact.

 

CP61, Page 9

--------------------------------------------------------------------

 

The RAF representatives returned to the crash site several times over the next three days and many photographs were taken, and there was much discussion and theorizing. While the exact cause may never be known for absolute certain, it is our belief, based on our knowledge of the VariEze design as well as our previous experiences examining several crash sites somewhat similar to this one, that this aircraft fell essentially vertically onto the surface of the salt pan. It struck the salt crust in a nose low, wings level, but inverted attitude. There was no evidence of a spin, no sign of rotation at the time of impact. The engine was not developing power and, most probably, was not even windmilling.

 

Two of the the eight large wing attach taper plugs were missing. We believe they departed the airplane in flight, as did the AN-4 bolt and nut that secures them in place. When the remaining six taper plugs were removed, they were easily removed without having to drive them out. All three AN-4 bolts had had the length of threads increased to about 3/4" using a threading die to cut these additional threads. All three bolts showed evidence of elongation of the threaded area where they had stretched possibly due to being over-torqued.

 

We theorize that possibly the fourth bolt was over-torqued to the point of failure, or almost failure. During this last flight, and probably aggravated by the acrobatic maneuvers, this bolt failed. None of the taper plugs fitted very well into the tapered holes in the wing fittings. For this reason, we believe that the two forward plugs on the left wing worked their way out of the tapered holes after the bolt broke, thus allowing the left wing to pivot aft on the aft two tapered plugs. There are marks on the left wing attach fittings which clearly show that the wing pivoted aft as much as 15 degrees.

 

The wing swinging aft by itself would not have caused this accident, however the winglet mounted on the end of the wing swinging 15 degrees left would create a powerful yaw with perhaps four times the authority of the rudder alone. Such a huge yaw angle would immediately drive the aircraft into a drastic departure from controlled flight. The airplane would flip over and experience heavy negative "G" forces which would cause the engine to starve of fuel, whereupon it would quit.

 

Apparently, this tumbling departure occurred at a rather high speed because the enormous negative, as well as positive "G" forces overstressed the aluminum wing fittings as evidenced by the considerable elongation of the taper plug holes in the outer plate, both top and bottom, of each wing. The inner plates of each wing fitting, top and bottom, showed much less evidence of elongation, leading us to conclude that the home made taper plugs did not perfectly fit into the tapered holes.

 

It is probable that the left wing, swept aft, may have caused the airplane to fall in a somewhat stable inverted spiral (as described by the eye witness). Flight experience and NASA testing have shown that a normal VariEze cannot maintain an inverted developed spin.

 

There is no evidence to suggest that there was any inflight structural failure of any composite parts. Every single part of this aircraft (with the exception of the two wing attach taper plugs and the securing bolt) were found at the impact site.

--------------------------------------------

 

IMPORTANT

All VariEze builders and flyers should be aware of the seriousness of this situation. If you know of anyone flying a VariEze who may not be receiving the Canard Pusher, please pass on the following critical information:

 

1) A mandatory inspection of the long AN-4, 1/4" diameter bolts and nuts that secure the steel tapered plugs into the wing fittings. There are four (4) of these bolts, each must be removed and carefully examined for any evidence of over-torquing (stretched threads, necked down diameter anywhere on the length of the bolt). Double check to see that the threads on each bolt are not bottoming in the threaded lower taper plugs. You may have to use thin shim washers under the head of each bolt to assure a proper fit with no bottoming of threads. Check that the jam nuts have at least 1-1/2 to 2 threads showing after they are tight. If you purchased your VariEze wing fitting from Ken Brock Manufacturing, you will notice that the AN-4 bolts have a longer

 

CP61, Page 10

--------------------------------------------------------------------

 

than standard thread (Joe Person Note - these were not AN-4 bolts, they were a Grade 8 bolt that were cadmium plated like an AN bolt is). These threads as they are on any AN bolt are not cut threads, they are rolled threads. If you see any evidence of the threads having been cut with a threading die, discard them and install new bolts.

 

Look for any corrosion on these bolts. Any corrosion should be carefully cleaned off and the bolts should be greased before re-installing them. Excessive corrosion is cause to discard the bolts.

 

If you did not personally install the bolts, you may have to assume that they might have been over-torqued. Any suspicion of over-torquing is cause to discard these bolts.

 

If your wing attach fittings were not manufactured by Ken Brock Mfg., you will need to carefully inspect the tapered plugs for perfect fit in the tapered holes. If in doubt, you may have to carefully lap each plug into its tapered hole, checking for perfect fit with engineering blue. Check to be certain that the tapered plugs do not go too deeply into the tapered holes. The top of the plugs must not go below flush with the top of the wing fittings.

 

The design of a wing fitting such as the VariEze calls for the tapered steel plugs to take all flight loads. The AN-4 bolts should never see flight loads. All they are for is to retain the tapered plugs. If the tapered plus are a perfect fit, these bolts will require only a very light torque to snug the plugs into their respective holes. Three (3) foot/lbs. (36 inch/lbs.) of torque are all that should be required. If you need more torque to pull the tapered plugs into their tapered holes, your tapered plugs do not fit correctly. Do not fly until you have corrected this situation.

 

Two people have died because of improperly fitting wing attach taper plugs. Do not take this lightly. Your life depends on these wing attach fittings. You owe it to yourself and your passengers to do absolutely the very best work you are capable of here. This is especially true if your wing fittings are homemade. The Brock fittings are very accurately machined and all the tapered plugs are hand lapped and fit perfectly.

 

Once you have installed a pair of tapered plugs and torqued the bolt (3 ft./lbs), as a double check, remove the bolt and check for a tight fit of each taper plug. It should take a sharp blow with a wood drift to loosen each plug. If the plugs fall out or are not tight, they do not fit correctly. Fix this problem before next flight.

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Norm,

 

The pins' fit in the bores can be checked with engineering/Prussian blue. They need to have a very well matched fit. As for filing, I hope you intend to use a lathe.

 

When Ken Brock made the fittings (the original supplier), the pins were matched to the tapered reamer that made the tapered bore in the entire fitting assembly stack-up. This ensured a very good match overall.

 

The problem with poorly-fitting pins lies with an end-result of one of the .125 plates on the centersection spar picking up more of the load that the other. Example: If the inner plate picks up load before the outer plate does, you induce a bending moment in the glass sparcap itself. With the sparcap reacting this moment, worst-case, you can fail the sparcap in bending before you ever get to design max g.

 

As for pin hardness, per plans the pins are supposed to be heat treated to 125 ksi. You do not want to begin any distortion of the pins at lower loads.

 

Stock pins were 4130, heat treated to 125 ksi, with a cadmium plating. By design, included angle was supposed to be 10 degrees. Generally, Brock-manufactured pins dialed in between 9.2 and 9.7 degrees or so (based on measurements I made on an optical comparator on 4 different sets of Brock pins, over sevral years).

 

Properly manufactured (correct materials and such), and with correct geometry/fit, the VEZ wing fitting is very robust and will give a long service life. You should not have to be concerned with "pins wearing out". Again, all things being correct, the pins will not wear out, nor will the bores. Gerry Gardiner, of Sheridan, WY, has a 4500+ hour VariEze built in the 1970s. He trailers his Eze to and from the airport (since day-one, effectively), for every flying session, which entails wing removal/installation far beyond what almost all of the operational VariEze fleet experiences.

 

Torque for the through-bolts is 36 - 40 inch-pounds, no more. If you have to use more torque to snug things up, something is not right. Refer to CP 61 for critical information on VEZ taper pins, and what can happen if the wing/centersection interface is not rendered correctly.

 

I'd plan on going through the airplane with a fine-tooth comb. One of the most important aspect of these types of airplanes is that each is unique. Some are built/integrated better than others. Be cautious, and be careful whom you rely on for help online. Read ALL of the CPs - those of us who built these airplanes (the conscientious ones, anyway) had to read all CP information associated with our airplanes. Familiarize yourself with your airplane's configuration, based on the plans and CPs.

 

Feel free to give me a holler anytime - ezejoe@comcast.net.

 

Meantime, read the excerpt from CP 61 (below), and go have an Emu beer for me...

 

Cheers,

 

-Joe Person

EAA Tech Counselor 4418

VariEze N79JN

Bothell, WA (KPAE)

 

From CP 61:

 

IMPORTANT

All VariEze builders and flyers should be aware of the seriousness of this situation. If you know of anyone flying a VariEze who may not be receiving the Canard Pusher, please pass on the following critical information:

 

1) A mandatory inspection of the long AN-4, 1/4" diameter bolts and nuts that secure the steel tapered plugs into the wing fittings. There are four (4) of these bolts, each must be removed and carefully examined for any evidence of over-torquing (stretched threads, necked down diameter anywhere on the length of the bolt). Double check to see that the threads on each bolt are not bottoming in the threaded lower taper plugs. You may have to use thin shim washers under the head of each bolt to assure a proper fit with no bottoming of threads. Check that the jam nuts have at least 1-1/2 to 2 threads showing after they are tight. If you purchased your VariEze wing fitting from Ken Brock Manufacturing, you will notice that the AN-4 bolts have a longer

 

CP61, Page 10

--------------------------------------------------------------------

 

than standard thread (Joe Person Note - these were not AN-4 bolts, they were Grade 8 bolts that were cadmium plated like an AN bolt is). These threads as they are on any AN bolt are not cut threads, they are rolled threads. If you see any evidence of the threads having been cut with a threading die, discard them and install new bolts.

 

Look for any corrosion on these bolts. Any corrosion should be carefully cleaned off and the bolts should be greased before re-installing them. Excessive corrosion is cause to discard the bolts.

 

If you did not personally install the bolts, you may have to assume that they might have been over-torqued. Any suspicion of over-torquing is cause to discard these bolts.

 

If your wing attach fittings were not manufactured by Ken Brock Mfg., you will need to carefully inspect the tapered plugs for perfect fit in the tapered holes. If in doubt, you may have to carefully lap each plug into its tapered hole, checking for perfect fit with engineering blue. Check to be certain that the tapered plugs do not go too deeply into the tapered holes. The top of the plugs must not go below flush with the top of the wing fittings.

 

The design of a wing fitting such as the VariEze calls for the tapered steel plugs to take all flight loads. The AN-4 bolts should never see flight loads. All they are for is to retain the tapered plugs. If the tapered plus are a perfect fit, these bolts will require only a very light torque to snug the plugs into their respective holes. Three (3) foot/lbs. (36 inch/lbs.) of torque are all that should be required. If you need more torque to pull the tapered plugs into their tapered holes, your tapered plugs do not fit correctly. Do not fly until you have corrected this situation.

 

Two people have died because of improperly fitting wing attach taper plugs. Do not take this lightly. Your life depends on these wing attach fittings. You owe it to yourself and your passengers to do absolutely the very best work you are capable of here. This is especially true if your wing fittings are homemade. The Brock fittings are very accurately machined and all the tapered plugs are hand lapped and fit perfectly.

 

Once you have installed a pair of tapered plugs and torqued the bolt (3 ft./lbs), as a double check, remove the bolt and check for a tight fit of each taper plug. It should take a sharp blow with a wood drift to loosen each plug. If the plugs fall out or are not tight, they do not fit correctly. Fix this problem before next flight.

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MacGyver, thanks for taking the time out to write this important info. for all to see. Being a home made plane, one should should take into consideration that any part of the the construction could be inadequate. A donated varieze had it's wings tested to distruction and failed at 7 g's-much less than expected. Was attributed to maybe not enough fibre glass in critical areas. One should fly a home made plane of unknown quality with as little g's as possible-slow speed in turbulance, moderate angle of bank, gentle landings.

I'll retorque my pins as I probably used 5-10 foot pounds, and see where they sit. A couple sit now 2 or 3 thou below and the rest are flush or higher. They are very hard to pound out [including the one I made] and need a brass bar as a wooden dowl won't move them.

A note again on making a pin, I would like to develop a modified pin that can be home made just on a lathe. To harden the pin and grind to shape requires specialized equipment. How about a pin that is solid with only a very small recess in the top for the bolt head and bottom nut. This would require longer bolts. It might not look so neat, but would be very strong in shear and not distort. When I first saw the origional pin, it stood out as being poorly designed. It's strength was severely compromised in order to get a neat result. What do you think, MacGyver?

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Norm,

 

Properly set-up, the wing fittings are good to about 16 gs - plenty-strong. In overload, and assuming you do not fail glass structure, the aluminum .125 plates on the centersection spar will fail in a shear tearout mode before anything else does, and the pins will remain OK. Not theory here, BTW, but evaluations of three separate VEZ crack-ups I have assessed directly (including one of my own in 1998).

 

Original pin design is more than adequate, and remember, Burt was extremely concerned about weight, as all good designers (and builders) should be. The per-plans pin design was a refined one, from a strength-to-weight perspective. Burt was not a designer to compromise anything for a "neat" result. In fact, he is quite the opposite.

 

Your idea for solid pins sounds fine.

 

5-10 foot-pounds is too high, as you have discerned.

 

Press on!

 

-Joe Person

EAA Tech Counselor 4418

VariEze N79JN

Bothell, WA (KPAE)

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MacGyver,

You're right about saving weight. You could build a plane out of steel that will survive 100 g's but it will never fly. Also, if the wings break off elsewhere at say 13 g's, which is a figure given to me for the varieze, no point making heavy pins that survive many times more. I take back that the pins were poorly designed. My homemade pins however need to be heavier to do the same job. That's a better assesment.

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Does your carb air intake system have the standard 2 1/2 inch ducting? The scat or sceet type can be sucked closed if it gets old and tired. The sceet may look good on the outside, but loose on the inside.

WTJohnson

....................................................................

I have seen another EZ flyer still use a Sceet hose even after I told him the issues with it.......It must be because it 'Looks' so nice and that the innner wire will not move.

 

So those who still want to use a duct with an inner liner, just imagine where that material can end up......right in your carb. I hope anyone using Sceet or Ceet ducting in your air intake system will get rid of it. Just because you may have paid for it does not mean that it is the right item.

 

Also, check the Scat and Cat hose regularly to make sure that the inner wire has not pulled loose and is allowing the duct to collapse.

 

WTJohnson

Varieze N725EZ .....FF in 1981......

Lake Stevens, WA

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No loose ducting that I can see, WT. Wish I could see something wrong somewhere. Fixed a car once that was smoking badly. After doing up the rings and head, still smoked. It had a mechanical fuel pump under the rocker cover which had a broken seal and was sucking oil into the fuel. Replaced the pump, but engine was still blowing smoke. At this stage going semi-nutso. After some research, found out the automatic transmission had a pipe leading to the intrake manifold. The vacume helped shift the gears. There was a valve that prevented transmission fluid from being sucked up into the manifold. Repaced that and solved the smoke problem. This aircraft engine might go the same route.

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G'day Very Easy,

 

I see you have listed your location as Perth WA and I am wondering why you haven't (maybe you have) contacted the local resources with your problem.

 

There is a local fellow at Jandakot who is both a VE owner/builder/LAME and also an engine overhauler with considerable knowledge on all facets of the VE.

 

Your static RPM does sound a little low, mine pulls about 2450 static but I can't off the top of my head recall the pitch (not at home at the moment).

 

Your IAS of 120 sounds comparable to mine given your static output.

 

It sounds very much to me that you really should bring a LAME in on your engine problems at least, dead sticking a VE won't be the most fun you can have :)

 

I'm happy to swap out your prop for a trial if you can get your aircraft to SEN sometime.

 

Regards

Mick

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Hi Mick,

Thanks for your advice. The previous owner in the USA had intermittant problem of the rpm dropping from 2800. When I looked at the plane, no problem. Since it has been in Australia, 2400 rpm is the most I can get in cruise.[might have something to do with water going down a sink in opposite direction] Got a further number of tests to do. The Varieze is at Narrogin and will stay grounded till I go through the whole a/c in greater detail than requred to get the c of a. I heard of that lame at Jandakot, but he is far away. Thanks for the offer of the prop, but the engine ran well before with the one I have. Do you have a varieze at Serpentine? I live close to there.

Norm

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