VG-21 SQUADRON

NEWSLETTER

ISSUE # 31

When searching for the accident report on Doug Donaldson's airplane, I found several others. Since fuel exhaustion seems to be a common occurence and the Varga fuel gauge system seems to get much of the blame, I thought it interesting that none of the following reports mention the fuel system as a cause. Perhaps the NTSB and FAA don't consider a malfunctioning fuel gauge system to be a contibuting factor.

If you have a computer, a friend also told me how to search for aircraft on the web by using http://www.landings.com. This web site may be of use to some of you. Try it.

Merced Antique Fly-In: June6-7, 1997. I have been told that this will be the last fly-in to be held a Merced. I try to get there every year to meet with my brother who drives down from San Jose. Although I always hope for more, there are usually one or two other Vargas there. It would be nice to see you there this year.

Northern California VG-21 Get-Together: Lee & Pat Beery would like to announce a lunch get-together in Northern California to celebrate the first meeting of the VG-21 Squadron they hosted back in 1990. It will be at Watts Woodland on June 14, 1997. I encourage all who can to try and be there.

Eagle Tail Flyers Breakfast/Social Club: Dave Wells (Varga 215A, N5068V) sent a note listing several breakfast date for those of you looking for a place to go on weekend mornings in Arizona. I missed the May 10 breakfast at Deer Valley Airport but the following schedule should give you an idea of what they have planned. Phone (602) 841-1229 for details. Dave also says to call a friend and ask them to fly in too.

May 17: Taylor, Arizona, 8:00 AM.

May 24: Open for Dave and Alice Wells who will be in Greer, Arizona.

May 31: Open for suggestions?

June 7: Show Low, Arizona, 8:00 AM.

June 8: Flagstaff, Arizona, 8:00 AM.

June 28: Mogollon Airpark, Overgaard, Arizona. BBQ lunch 10 AM - 2 PM. This is also an annual Fly In

event. Contact Michael Campbell at (602) 661-7586 or e-mail at telmike@futureone.com for

details.

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TRADE-A-PLANE, SECOND APRIL ISSUE, 1997:

1979, TT 1153, 868 SMOH, annual 5/96, good condition.

$33,000. Stan Allen, 706, 865-0793. or trade

for C-170B w/Lyc. engine conversion. Will deliver for

expenses.tf

SHINN 2150A, 1860TT, 500 SMOH, excellent condition,

$29,500 with fresh annual. 540, 884-2675, after

6PM EST. VA/ap2

1979 VARGA KACHINA, TT 1068 A&E. KIng

KX-170B Nav/Com, KT-76A xpdr, Mode C, Sigtronics

ICS, auto gas STC, strobes and more. New overall white

sterling polyurethane paint scheme. Screaming Eagle

Aviation, http://aso.solid.com/ad/14242 or call 805,

525-7121; FAX 805, 525-4772. tf

SHINN 2150A, LOW TIME engine, clean airframe,

well equipped, ready to go, sale or trade, $32,500.

417, 926-4221, fax 7272. ap3

2150A, 1979, 1100 TTSN, like new, Collins, Garmin

GPS, Apollo 618, all accessories, covers, etc.

$36,500, 919, 928-7489. my2

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VG-21 Membership: A $20 annual donation will cover all the printing and mailing costs for at least four issues a year and will help pay for return phone calls, letters and postage when you have questions or comments that require a quick or personal response. Beery VG-21 Newsletters: $10 covers most of the printing and mailing costs for all issues. Old Bishop VG-21 Newsletters: $1.00 per issue (includes postage).

For those of you who don't know, I am the former Varga Aircraft Corporation engineering manager (1975-1982) and may be able to help you with a problem. I can be reached at:

2062 West Gila

Chandler, Arizona 85224

(602)786-3578 (evenings)

(602)891-6152 (days)

You may also be able to find me at hanger A9 at Falcon Field in Mesa.

Ron Judy, Varga () N() and Alex Thurocy, Varga 2150A, N8273J are new members.

John A. Ward, Varga 2150A N8293J (disassembled) of Eugene, Oregon is also a new member.

Cleave Murdock is looking for the carb air duct that attaches to the front of the carburetor heat box. His is cracked near the flange that attaches the duct to the heat box. While inspecting his airplane, he also discovered that the screw holding the vacuum system air fiter to the back of the firewall was sticking out the front of the firewall directly behind the fuel hose that goes to the fuel gauge. This screw was not easily visible when the cowl door was opened and was wearing a hole in the fuel hose. Not good! You might want to check those items on your airplane.

Rosemary DeAngelo finally got her airplane back from the paint shop a couple of months ago. Unfortunately, someone just ran another airplane into her left wing while it was parked on the ramp and she is now in serious need of a left wing and/or parts thereof. Can you help her?

I got the following E-Mail letter from Tim Keith-Lucas:

Very glad you've gotten email- that simplifies communication a great deal. N4614V will fly as soon as it is weighed (the owner of the scale is ill) and the weather improves. It has passed its annual and is completely assembled, but repairs will require weighing.

The repairs were as follows: replace propeller, inspect crankshaft (no damage), rebuild engine mount, replace nose wheel fork, replace the nylon bushings in the front strut, double the lower third of the firewall, replace the lower cross tube of the airframe just behind the firewall, replace the two steering rods, and replace the throttle cable. Minor fiberglass work was needed on the nose bowl and the lower cowling, and I lined the asbestos boots for the steering rods with knit Nomex. The total bill will be a bit under $10,000. Unrelated to the accident I replaced the windshield and had the exhaust system rebuilt.

We rebuilt the engine mount with heavier tubing (same inside diameter, thicker wall, bored to fit over the stubs). Rolf's jig was essential to the task; it's a beautiful piece of work in it's own right. We also used heavier tubing for the nose wheel fork: The machinist used your drawings to make a jig at a cost of about $450, tamped sand into the tube, welded it shut and then bent it. The jig still exists if anyone wants a fork made; I could not afford to buy it from him however.

This accident occured while I was back-taxiing because I hurried off the active runway to let another airplane land, and hit the edge of the pavement. Instead of rebounding, the nose gear jammed in it's compressed state because the nylon bushings were original and had cracked. The machinist had fun getting it apart. Apparently the wheel fork failed first, and the drag from the fork on the pavement bent the engine mount tubes. there was no damage to the strut.

Aside from encouraging others to learn from my error, I do plan to inspect those bushings each year. Since the FAA doesn't mind heavier tubing, I thought it best to strengthen the basket, even at $8.00 a foot for tubing.

I'll be back to you with dimensions, and will hold on to Rolf's jig until I can hear from anyone who needs an engine mount repair. I the meantime, thank you very much for your kind assistance, without which I would have some very expensive scrap metal. Having received so much from other Varga owners, I will do my best to contribute in the future.

--Tim

TImothy Keith-Lucas, Ph.D.

Professor of Psychology

The University of the South

735 University Avenue

Sewanee, TN 37383

615 598-1317"

 

Tim's E-Mail address is: tkeithlu@seraph1.sewanee.edu 

I also got a letter from Lee Beery with information I think is worth passing on and am reprinting most of it here.

I don't think it'll take anything out of his hide but I do have a couple of comments about Lee's letter. I hope he'll take them more as information than as criticism. I did say in newsletter #25 that we didn't pursue aerobatic certification because of money and time. I didn't say why it would take money and time. We knew it wouldn't ever make a good competition aerobatic airplane but we did have a lot of doctors and lawyers and such that wanted to do an occasional roll or loop but needed to be assured that the airplane would take, and was certified for, aerobatic loads.

While making changes to the elevator control system to solve a problem and in certifying the 2180, I did static load tests on the stabilizers, elevator and rudder. Although these tests weren't all to aerobatic load limits, the problem I saw was not strength but stiffness. A specific example was the rudder which easily passed it's static load test but the corrugated skin flexed so much that the lead shot bags were starting to slide off. When the weight was removed, there was no significant permanent deformation. When I designed the larger rudder, I added a spar between the ribs and it passed the load test without a similar stiffness problem. As for the hinges, FAR 23 says they "...must have a factor of safety of not less than 6.67 with respect to the ultimate bearing strength of the softest material used as a bearing." I won't show the calculations here but with ultimate loads in the 300-400# range and an ultimate bearing strength of about 100,000# for 2024-T4, I think the hinges are strong enough. Changing the flaps from spring loaded cables to push-pull rods and bellcranks wouldn't have been too big a deal. I did it on the airplane I built in Montana. I also made an ejectable canopy for the Montana Varga so I suspect it could be done on a regular Varga as well. Power to weight is not much different from a Citabria and better than a Cessna Aerobat so I don't understand that as a problem for a recreational aerobatic airplane.

Lee is right about spins. Perhaps the biggest aerobatic certification expense would have been in making the Varga spinnable. On the airplane I built for Montanair, I was told that it took more than a dozen spin tests before they were able to meet the FAA spin criteria by adding a ventral fin. I don't know if that would work with a standard Varga. There are probably lots of other little things that would have to be changed as a result of aerobatic certification load and flight tests but I assume they would all be managable.

I've been questioned many times since the factory closed it's doors about the weak areas to look for when an airplane shopper is looking at a Varga to buy. The first thing I usually tell people is to look underneath the wing where the main gear enters the stub wing to see if the skin is wrinkled around the gear. This is a sign of hard landings and that the outboard stub wing rib is damaged and needs to be repaired or replaced. The wrinkled skin should also be patched or replaced. When I had to do it, it usually took 8 to 16 man hours for this repair depending on how bad the damage was.

The next thing is to look and see if the main gear are bent. You can easily see this by standing at the front of the airplane and looking at the wheels see if they're sitting at an angle. Excessive wear on the inside of the tire can also indicate a bent gear but it may be a wheel alignment problem. Wear and tear on main gear torque links and bushings can be checked by grabbing the wheel, wiggling it back and forth and watching to see how many parts move in the the wrong direction. You may also want to jack each wing up and wiggle the gear while it dangles to see if the strut bushings are worn. It's a little easier to check the nose gear because it's not too hard to have someone hold down the tail while you shake the nose wheel around. Again, watch for parts that seem to move too much or in the wrong direction. Bushings, bearings and bolts aren't too hard to make or replace but there are not a lot of Varga manufactured landing gear parts out there and gear strut repairs can get expensive.

Look for cracks or bends in the inboard flap hinge. The maximum flaps down speed is pretty low so it's not hard to overspeed the airplane with the flaps down. This hinge may need to be repaired or replaced. NAS40 hinge is expensive but is still available and the hinge can be legally reinstalled with Cherry Lock or Cherry Max rivets.

Their is also a potential problem with cracks in the wing trailing edge ribs at the aileron hinge attach points but it is difficult to see this problem without removing the ailerons. You can try moving the aileron up and down vertically at the aileron leading edge and if the wing trailing edge skin appears to move or "can" near the hinges, there could be one or more cracked ribs. You will have to make some small reinforcing straps but there is an FAA 337 for this fix.

If the owner will let you take the side and belly panels off, you can check for rust on the steel tube fuselage truss, especially at the lower engine mount and aft fuselage attach points. Check the electrical wiring on the right side and throttle and trim controls on the left. If he's let you go this far, the owner might also let you take off the wing joint fairings where you can check the inside of the bottom wing skins for evidence of fuel leaks (the fuel on the outside gets wiped off). You can also look to see if any outboard stub wing rib repair has been done. With the joint fairing off you can check the flap bellcrank and push rod for wear and tear by watching it move while you lower and raise the flaps.

Check the flight controls for too much play. For example, have someone hold an aileron while you wiggle the stick left and right. A little bit of movement is normal but too much free play could indicate worn rod end bearings, bellcrank bearings or bolt holes. Do the same for the other aileron and the elevator. Although they are kind of pricey, I think Aircraft Spruce still sells the required rod end and bellcrank bearings.

Make sure the canopy moves up and down freely and smoothly and latches securely in all positions. The latching part is especially important!

After a personal experience with a brittle 2000 hr old fuel line that broke, I'm a firm believer in replacing every rubber hose that's more than 1000 hours old. Check the log books to see if they've been changed at least that often or plan on changing them yourself if you decide to buy the airplane.

Another rubber part that deterorates over time is the conical engine mount bushings. Look at the front of the airplane to see if the prop and spinner are misaligned much. If so, the engine may be sagging from worn mounts.

The rest of an inspection is mostly looking for the same damage, corrosion, functional defects and wear and tear that you would see on any 15 to 30 year old airplane.

Lee Beery asked about my airplane and I'm happy to report that, so far, all of the modifications I made are working great. I did have a fuel siphoning problem with my auxiliary fuel tank and had to reroute my vent lines to correct it. Although my oil consumption is higher than before the overhaul, it has stabilized and all my spark plugs are dry. As Lee implies, I may have to do something to keep my oil warmer because it hardly ever exceeds 160 degrees. And yes, 5 minutes is way too much time to spend upside down but, except for my bladder, having two extra gallons on a long trip can't hurt, right?