Construction Details Finish&Fly Events and Projects Building from Plans Raw Materials Q&A Tools Construction Log

Date Contact Question and Answer
December 28, 2002 Zenith List  Is there a simple way to make the Sharpie permanent markers (ultra fine point) useful more than once? I got several responses:
"I keep the cap on when not in use, and store them verticaly, point up or down, it does not matter. Sometimes I have to trace a short line (<1 cm) top get them started, but that's all. Note: temperature in my workshop (in basement) is always above 17 C."
"When my sharpies dry out a put a couple drops of Laquer thinner on them and they work fine until they dry out again, then I just use a couple of drops more. Hope this helps. Oh yes I don't buy the real sharp pointed ones, medium seems to work the best as the point materiel is softer."
"The ink seems to "harden" on the tiny flexible tip. Lay the pen against the metal at about a 30 degree angle, push slightly to bend (not break) the tiny flexible tip and rotate the pen barrel 720 degrees (that's two revolutions for you Canadians) while holding the tip in a slightly "flexed" position. This seems to "crack" the hardened ink on the tip and allows fresh stuff to start flowing. Keeping the cap on tight has never helped, they "harden" every time."
February 24, 2001 Zenith List I got one shinny 6061-T6 0.016" aluminum sheet.  The other ones are dull looking.  Markings are the same.  Is this OK? Several members of the list had similar situation with their Zenith Aircraft's supplied kit. I got this explanation: "The surface finish is totally dependant upon the "finish" on the surface of the rolls used in the mill to roll the aluminum, this surface is ground into the working roll to achieve a desired finish on the metal, is is quite possible that the bright sheets had been produced for Truck sides, and as the alloy is the same irrespective of the finish obtained by rolling, these bright sheets are sent to the wholesaler for general use, along with "mill finish" general use sheets, I would expect that the alloying numbers T6061 are correct." Others commented that after the part is primed, no difference is apparent.
February 19, 2001 C. Heintz I want to make landing gear forks using 1/4" 6061-t6".  They will be larger (width of 6.5" inside. Is it OK? Yes, no problem, ensure that the radius is adequate (my suggestion of 1" is adequate).
Can I make the fork by joining two L's, having the doubler on top and a plate underneath? Yes, bolts should be at least 1/4" and ideally 5/6".
I will not be able to have 13mm edge distance on stabilizer attachment plates.  Can I use 0.050" 4130N instead of the 0.063" 6061-T6? Yes. With the aluminium plate it is important to respect the edge distance.  No problem with the steel plate, but assure that it is properly primed.
February 4, 2001 Zenith List When I align bottm skins 6F1-1 and 6F1-2, I do not obtain a straight line on each side.  This is normal and it is described in the detailed sequence manual on step 11.
October 24, 2000 B. Bockius How do you drive your gyroscopes (Venturi, pump or electric)? I'm using a 9" Super Venturi. It doesn't work. I've tried it on the right side of the fuselage - just below the upper longeron and aft of the firewall, and in its current location on the bottom of the left center wing (just aft of the main spar and inboard of the gear). Neither generate more than 2" maximum vacuum. Doing it over again, I'd go with electric gyros, powered by either of the two batteries I already have for the Subaru 
September 6, 2000 N. Heintz Where do I need to drill drain holes? As per the plans, drain holes are needed in the rear fuselage.  There should not be any drain holes in the flying surfaces (wings, ailerons, etc).
June 26, 2000 N. Heintz Can I position the aileron ribs in line with the main wing ribs?
Yes, no problem doing that.  May also add an additional rib at position 130.
June 24, 2000 Zenith List When do we set aileron twist?  After the ribs drilled or before?
General consensus is that we drill one side (the bottom), then set the twist and drill the rest.
June, 2000 Many! Should I slosh my fuel tanks?
Some people are afraid of sloshing compounds.  However, I know at least two individuals that did it and they have no problem after several years.  I called Randolph and asked.  They, like several other people, said that if the tanks don't leak, they should not be sloshed.  However, from practice, I know it may be quite hard to detect small leaks (some won't reveal after many days,,, with pressure in tank).  Like my mentor did 5 years ago, I decided to stop worrying and put Randolph 912 sloshing compound (this one is compatible with Alcohol).
Oct. 12, 1999 N. Heintz What is the material for 6V4-7 (3/16" rear plate) (6061-T6 or 2024-T3)?
We use 6061-T6,  2024-T3 can also be used.
It is OK to use 6061-T6 for all spar caps and spar cap doublers and front plate (6V4-8)?
 I have 8 oversize rivet holes (between stn 1800-2400) on my left spar (upper spar cap).  Can I use AD6 rivets in these holes (redrill with #12)?
On the same spar, same side, the 1/4" (AN4) hole in at 50mm  from the end of the spar cap doubler is oversize.  Can I use a AN5 bolt with 5/16" hole in this location?
Yes, you may want to consider drilling pilot first.
Sep. 27, 1999 N. Heintz I want to install LE tanks. I understand that I have to install a new LE rib at stn 170 and move the 650 rib at stn 965 (NOT 960!!!--this is what I have done and it is not good).  The tank is about 760mm wide. The question: what is the proper position and size for the fuel line hole in the 130 and 170 ribs? I read in the builder manual that holes should not be less than 38mm from a flange and should be at most 1/2".  This guideline does not seem appropriate for that particular use.
The above is for most holes regardless of their location. You are 
right, the holes in the nose rib will be larger and closer to the
How do I install the flush fuel cap?
Weld a pipe on the tank.  That the fuel cap fits into that pipe.  It is not really flush with the skin becaused there is a curve in the leading edge skin.  There is a variance of about 3mm in the fit with the skin.  (Hearing this, I think I will go with standard caps).
Sep. 24, 1999 N. Heintz  I have four additional rear ribs 6V1-2.  Would this be a good idea to use them in place of the L stiffeners on the top and bottom outboard wing skins?
It is not necessary.
I read in one newsletter to verify that we have the pages 6E5 and 6E6... I don't have a page 6E6. What should I do?
Sorry for the confusion, these pages are part of the engine installation package. The last page of the drawings is 6E5
Finally, I formed part 6F8-2 with a front flange that is narrower than what is called for in the plans.  It has 17mm instead of 20mm.  Will this be a problem? Should I remake the part?
I would not worry too much about it, try to make the parts as 
shown in the drawings! 
September 11 and 13, 1999 Jack and Art (Flypass) I formed 6V4-2 (the spar cap doubler) to plans and it does not fit.  Can I undo the aft 45 degree bend and rebend in proper position (about 4mm aft)?
Ok for THAT bend.  An alternative is to make a new part (I only have 0.040" remaining, which would be Ok).  Note: I remade this part on Sep 21 using 0.040" aluminium.
Is there anything special regarding canopy height or cabin lenght on your red demo plane (i fit comfortably in it... which is not the case in all planes)?
No. It is built from the kit to plans.  One thing... the canopy is higher now that it has been in the past (year not discussed).  Art is not sure that the 1995 plans reflect the new canopy.
August 25, 1999 A. Mitchell Can I use ribs similar to the gear box ribs (no front holes and reversed flanges on back holes) for the baggage lockers?
Yes. Consider putting L stiffeners in place of the missing holes.  I also told him that I intended to run wires in L angles over the holes... he said it is a good idea.
What is the maximum depth of a scratch that I can sand (how much material can I remove)?
Generally, with 6061-T6, you don't need to bother with small scratches (except for the spar and spar doublers).  He told me about a 10 times rule (such as for propelller), but I did not understand.  In my case, I have a scratch lenghtwise following a radius of a rib.  He proposed to make a new rib.
What is the best technique to rivet a spar?
A rivet gun is the best approach.  I could also try with a harbor press.  Make sure to practice because it is quite hard to be stable with a bucking bar and a rivet hammer.
Where do I find the tie-down ring?
Auto parts.  Make sure to get one with the ring forged close and a flange.
July 12. 1999 N. Heinz Can I move the upper L angle (Elevator) 5mm away from the doubler cut out?
The purpose of the L angle is to reinforce the cutout.  Moving it is not ideal.  (My solution... I ended up not having to move it very much... about 2mm)  Do we need to rivet the upper horn on the flange overlap (with piano hinge)? And is edge distance on piano hinge important?  The edge distance for this hole on the piano hinge is not important.  Because the part is cut at an angle, it may be difficult to drill on the flange overlap.  However, if it is possible, it should be done (even if do not respect inside flange edge distance).  My solution:  my part is cut square instead of at an angle.  I was able to drill it on my piano hinge rivet line.
June 30, 1999 A. Mitchell My rivet line on the top front spar stabilizer skin is too near the radius of the spar... what should I do?  Also, I damaged several rivets holding the doubler to the spar.
You can add a rivet line offset 20mm at the right position.  For the damaged rivets, replace them.  You can avoid damaging rivets in similar situations by setting the rivet  pitch at an offset.
June 30, 1999 N. Heinz &
B. Hunter 
Curiosity, is it true that lead pencil may affect the aluminium?
Lead is a different metal than the aluminium allow.  As a result, it may create corrosion and weaken the structure.  If you use lead, you should remove (erase it).  It is better to use other types of markers.  
Update on July 20, 2001 (I received this from one of my visitors):
Pencil leads were once made of lead. That time is lloonngg gone. The "lead" in modern pencils is made of graphite and clay. The clay content determines hardness.
June 30, 1999 N. Heinz If my drill an elongated hole in a skin, can I replace the A4 rivet with a A5 rivet?
Yes you can do that.  However, if you do this often, consider pre-drilling with #40 drill bit prior to drilling A4.
June 30, 1999 N. Heinz I want to build my own leading edge gas tanks... how are they designed/installed?
Make an additional rib that faces inboard 40mm after station 130.
Move rib of station 650 to a new location (965, NOT 960).
The gas tank has the same profile as the wing... just a little bit smaller to allow to be enveloped in cork.
The fuel line should go through a hole at the bottom of the ribs near the flange (better this way than through the spar).
For flush fuel cap, order from aircraft suppliers and test for compatibility with auto fuel.  The gasket may not be compatible.
June 22, 1999 A. Mitchell (Flypass),
Zenith List
Front stabilizer attachments protrude only 22mm.  How should I drill for fuselage attach.?
Do not drill now.  Wait until I attach stabilizer to the fuselage.  I can use either a right angle drill attachment to drill the hole, or I can use a one foot drill bit.  Frank said he drilled 1/8th of an inch first and then he back drilled to 3/16".  Thanks to Frank Hinde, James Tannock and P. Walsh from the Zenith List.
April 22, 1999 Jack (Flypass) Which hinges are installed on the CH-601?
MS-20257 (if I understood right).  Anyway, these are not the extruded hinges.  The ones that are sold by Zenair are the open loops hinges.
April 7, 1999 A. Mitchell (Flypass) Referring to scratches, what does it mean to "file lenghtwise"?
File lenghtwise of the part, not of the scratch.   It is critical on the spar.  Minor scratches (the ones we don't feel) are not a problem.
April 7, 1999 A. Mitchell (Flypass) My rudder spar is shaped like a banana...
This is normal.  If only light pressure is required to make it straight, take care when you rivet the skin that the spar is straight.... that's all.
April 7, 1999 A. Mitchell (Flypass) What is edge distance and how important is it really?
Edge distance is the distance from the center of the hole to the edge of the part or flange.  It is OK if the the rivet is near a radius.  In some cases, edge distance is not critical (for non-structural parts such as fairings).
April 7, 1999 A. Mitchell (Flypass) How smooth is smooth enough?
I explained that I sand on my ribbon sander, then with a roller sander on a drill and I smoothen the part by hand.  He explained that 6061-T6 is more forgiving than 2024-T3 of imperfections.  File or sander marks are acceptable with 6061-T6.  He said that I spend probably too much time smoothing my parts.   I must admit that I don't want any part to crack due to improper smoothing.
April 7, 1999 A. Mitchell (Flypass) When should I install the rudder bearing and horn?
I should install the horn now and the bearing when I fit the rudder to the fuselage. (Fernand Levesque and others told me that in the past)
April 7, 1999 P. Fournier Is the Zinc Chromate replacement product of Canadian Tire adequate for corrosion protection?
Yes, it is really good and probably less toxic than Zinc Chromate


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