Q-talk 62 - LETTERS
- Category: Q-Talk Articles
- Published: Friday, 28 February 1997 06:11
- Written by Tom Moore
- Hits: 1780
Hi Tom and Jim,
It sure was good to see Jim again at Kansas. I can't emphasize it enough how much that fly-in does to encourage and inspire me. Many thanks to Bob Malechek for the flight he shared with many others and me in his super Q-200. We were pushing 200 mph at one point. That's quite a plane he has built.
I recently spoke with Scott Swing about some parts for my Tri-Q conversion. He said he acquired the nose gear jigs from the older gentleman who used to make them for him. Scott went on to say that he has worked out a new nose gear based on Velocity parts with larger OD tubing and a cast aluminum gear. He says the new gear is beefier and this way he doesn't have to build two different things.
I have almost finished wiring my instrument panel. This has been more fun then I expected. Each circuit is pretty basic, a plus and a minus. Tony Bingelis' books have been invaluable in getting me through this. I've picked up a few things I'd like to share that might be obvious but they seemed to help me.
According to Aircraft Spruce, the wire shipped with the Q2 kits back in the 80's may cause toxic fumes in a fire. So, I ordered the new stuff to be safe. The old wire had a fiber mesh around the wire and a clear plastic outer sleeve. The new stuff just has a plastic sleeve that feels like nylon and has a slight gray cast.
I bought a used wire crimper from Airparts, Inc. in Kansas for about $20 bucks. You know the company. In their ads, they have the old lady who can't say "I've fallen and I can't get up!" because they have her propped up in the center of a roll of aircraft aluminum. You can get a catalog from them at 800-800-3229, (yeah, that is right). These used crimpers do much better then the cheap crimpers you get locally that make an oval crimp. The used crimpers put a very positive crimp on the wire and do quite well on the "pull test" and they are hard to mess up. They won't let you release the crimper until the crimper has reached a predetermined distance.
Cut the insulation off of a terminal and get a good idea of where the center of the crimp area is for the terminal. That way you won't crimp near an extreme end and get a bad crimp.
Look at the crimp area on the terminal you removed the insulation from. Notice there is a seam where the metal butts together to make the cylinder to hold the wire. Consider that seam as the Front of the terminal. The crimping tool I bought presses a projection into the terminal that has a notch for the wire. That projection should be pressed into the Back of the terminal or 180 degrees around the crimp area cylinder from the seam.
I bought a bunch of white heat shrink from Mouser Electronics. You can get their catalog by calling 800-346-6873. I bought white so I could label each wire with a Sharpie pen. Heat shrink will shrink to about 50% of its original ID when heated. Make sure you measure the wire you will actually use in your plane and order between 1.5 and 2.0 times the OD of the wire for a tight fit.
In addition to the white heat shrink, I bought some black heat shrink and marked each ground wire with both black and white heat shrink. Aircraft Spruce sells the new wire with a black stripe down it that could be used for the same purpose, but this seemed just as effective for me.
Slip the heat shrink on the wire before you crimp the terminal. I know it sounds stupid to say that, but I'm sure I'm not the only one who had to either try and slip the heat shrink over the terminal or worse, cut off and waste the terminal.
If you have long wire runs, it can be helpful to have some of the heat shrink in the middle somewhere so you can mark each wire in the bundle.
Strip the insulation of the wire so the cut end of the wire just peeks out past the insulation of the terminal when the wire is pressed firmly into the terminal. Make sure you are crimping wire not wire insulation.
Pre-bend the wire in place too so you can rotate the terminal on the wire before you crimp it so you don't have to twist the wire later when you finally connect the terminal to the connector.
Jim Weir suggests using terminal block in his September 96 KITPLANES article about wiring. I'm glad I did.
You can test the wiring with a 9 volt battery, a standard LED and a 500 Ohm resister. Use an LED because you can check the polarity of your connection at the same time you test continuity. The 500-Ohm resister will help your LED from blowing up when you put on the juice. Radio Shack sells an LED with the resister already wired in for a couple of bucks that works well.
I incorporated a Master solenoid as well as a Starter solenoid to provide the best control over the main circuit as I could. Tony's Firewall Forward book has some good wiring diagrams to help with this switch.
I've included some pictures of my engine stand. I modified a normal engine stand by making some room for the magnetos by mounting the engine with 3/8" All-Thread and some black gas pipe spacers cut to the right length. I made some "clamps" for the simulated firewall by cutting a 1/2" lengthwise strip out of PVC pipe that was cut to the proper length. I found, when you cut the PVC pipe to length, if you cut the pipe in a very broad V shape that you can tighten the clamp with a twist of the wrist. This engine stand and the adjustments I made have been very helpful for wiring and running cables. I think the engine stand sells for under $50 from Harbor Freight at 1-800-423-2567 would work for this as well.
Dave Richardson, Stow, OH
Cutting holes in your firewall for the first time can be very stressful. Dave Richardson has come up with a way to try his ideas out before making the final plunge with the drill.
Q1 4251F survived its second first flight and became an experimental airplane again. I flew the last of the forty hours and 51FOX became a REAL airplane. Howard Hardy has been a great coach all along and most of my changes are the result of his suggestions.
Interaction with the outside world started when I tried to get 51F registered; that took about eight months. Next was rounding up a set of scales for weight and balance. I did five laps on the weight and balance because I wanted 51F to weigh correctly on the scales with no correction factors cranked into the math - and I blew it twice.
Two days later D.A.R. Terry Edwards came out for the airworthiness inspection. His only complaint was the lack of labeling throughout the ship, which I fixed on the spot with Dymo labels, and Superglue.
I had a little trouble getting the engine dialed in as the wood prop my (ex) girlfriend made turned out to have to much pitch (by the way; anybody with a 2.38 gearbox need a show-stopper prop?) Bob Bounds came to the rescue here by loaning his spare adjustable Warp Drive prop while Ivoprop was making up a new one.
At Howard's insistence I started slow taxiing about this time. The engine overhaul proved out well over the next FIFTEEN HOURS of taxi practice, as did the vertical pivot axis tail wheel bracket and rubber brake pads. The main problem exposed in taxi tests was spinning main axles, and, of course, the feisty ground handling. Two laps through both mainwheel bearing stackups finally fixed the axles and taxiing in bare feet kept the runway centerline under control.
By the way, how do you guys build these things without a machine shop? My hats off to ya!
Once I thought 51F was ready I called local tailwheel/test pilot guru Bill Mitchell to come out and do the honors. Bill's inspection turned up some sticky reflexor linkage that took about an hour to fix. 51F was then pronounced "armed and dangerous".
Next morning was it! One last lap on the different CG numbers with another pilot and off Bill and 51F went. Twenty minutes later and whaddaya know? No smoking craters not even a bounce. Bill's big smile was accompanied by two big surprises: 51F flies straight and honest, it was now MY TURN. Bill and Howard talked me into it - and I was feeling pretty sharp. So here we were - today's task: survival. Flight plan per Bill written on the kneeboard:
Takeoff checklist - twice:
Slight back stick at 65 mph
Cruise not more than 90
Experience pitch buck and slow flight above 3000 ft.
Do practice approaches until one feels good all the way down
Land and stop for the day - Yes Doctor -
I survived the first one and began testing. Using Advisory Circular #90-89 and a kneeboard and variometer (precision rate of climb meter), I started what I think is the most interesting part of the building process. Bill commanded me to LEARN SOMETHING on every flight, and I took this to heart.
The variometer is a great tool. I used my trusty Cloudbase hang gliding vario with several nice features:
10 ft. increment digital altimeter
Real time rate of climb range of +/- 1600 ft per min. in 25 ft/min. increments
20 second ROC averager option
Audio ROC option (for maintaining an altitude)
Excellent temperature compensation
The size of a cassette tape and mounts easily.
The vario was handy for doing stall tests. Keeping the vario at zero at a given altitude while bleeding airspeed, I would wait for pitch bucks, record data, change parameters and do it again and again. The first flight gave me a straight-ahead pitch buck at 60, CG at 48.3 inches, reflexor at zero, power off. On the second flight I pushed the airspeed envelope up to 120 IAS and noticed a slight elevator flutter after sharp impulse. I did another series of stalls at different reflexor positions. Tail down, aileron trailing edges up 1/2 inch gave pitch buck at 55. Tail up, with reflexor 1/4 down at the trailing edge, pitch buck was at 65. Doing accelerated stalls, it pitch bucked at 65 with the reflexor at zero, power on.
The engine seemed to be running a little hot so I checked fan belt tension, played with a little duct tape inside the cowling; there was no effect on the high CHTs. Changing the carburetor jets fixed the problem.
Next flight verified the elevator flutter starting around 100. Testing for aileron flutter, I noticed it damped out after three oscillations. Upon inspecting the elevators, I noticed 1/64 of slop between the "precision machined" phenolic bearing blocks and the elevator torque tube. Back in the machine shop (how do you guys build these things without one?) I pressed a pilot into a 3/4 inch hole saw and turned the hole saw down so it would drill the correct size hole for a Thompson nyliner. All flutter problems disappeared after these were installed on elevators and ailerons.
Next I changed the IVO prop from three blades to two, giving a static run up of 6000 RPM and another 10 MPH on cruise speed.
Full rudder deflection slips in both directions yielded 1100 fpm down at 80 MPH and a mild departure below 65. On the next flight, speed runs working up to 140 resulted in no flutters anywhere. I had no problem with a takeoff with the reflexor full tail down; it jumped off the ground at 55. The following flight I did a long climb to 12,000 ft at 80 MPH. Nineteen touch and goes fried the brakes.
At this point I checked and tuned the engine, checked the wheel bearings, changed brake shoes, changed altimeters, installed a G meter and added cabin exhaust vents. I had to hunt forty miles for a wet cloud to do a rain test. The power off pitch buck speed went up 5 MPH in the rain. (The VGs do work.)
Next I took the sliding weight out, moving the CG to 47.3 and did a stall test series in that configuration, working up to 15 MPH crosswind landings.
I taped the gap at the tail separation cut line and eliminated the exhaust smell in the cabin. Removing the tail, I inspected the reflexor linkage, reinstalled the sliding weight at 49.4 CG and went back to stall testing. Adding ten lbs of baggage moved the CG to 50.4, causing power on pitch buck at 50 - scary! Just to stay nervous, I pushed VNE and flutter tests up to 150 and performed a 3g departure stall at 80.
Cross-country trips were relatively calm. On my first XC flight I burned 4.1 gallons per hour and cruised low enough over I-25 to read the mileage signs; 100 indicated equaled 120 true (this means I actually pushed VNE up to 170!).
Ian Huss, Boulder, CO
Thought I would write a note to bring you up to date on Q-2 85BJ. I first flew 85BJ on 10/86. It was built exactly to plans with no deviation except beefing up tail spring and putting on larger and wider tail wheel.
The Q-2 has always flown beautifully with no bad habits and I have logged 565 hours on it. This fall when doing normal maintenance, I discovered a small oil leak on top of the engine, in the middle of that flat machined area where the oil cooler sets on the original VW engine. You couldn't see a crack but obviously there was one there. I called Revmaster and discussed the problem with them. They indicated to me that cracks had shown up in just a handful of engines over the last 15 years caused from fatigue, heating, cooling, etc. Well, I ordered a new case from Remco out of California made from a new aluminum alloy that's supposed to be better than the old cases. Remco makes the cases for Revmaster and I saved a few bucks by going direct. However I had to have some machining done locally that Revmaster would have had done. I ordered all the parts I needed to rebuild the engine from Revmaster and found their prices very competitive and their support very positive. Don't hesitate to call Revmaster with any questions or problems you may have. I found them very eager to help. Phone # 619-244-3074 and ask for Joe or Allen.
Well, I have the Q-2 back flying again and the little Revmaster sounds like a Singer sewing machine. I assembled the engine myself and found the work very rewarding. I also know how to service the engine better after knowing how it all works. I look forward to flying many more hundreds of hours in my Q-2.
By the way, does anybody know where we can get a new gas cap to fit our Q-2's? (The big plastic job that came with our kits.)
Robert Gillespie, Twin Falls, ID
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