Q-talk 60 - LETTERS
- Category: Q-Talk Articles
- Published: Thursday, 31 October 1996 06:11
- Written by Tom Moore
- Hits: 1894
A LETTER TO "THE GUYS" -
If you have a "significant other" who is less than thrilled about your aircraft project and/or has no interest in attending the Ottawa Fly-In with you, please share this letter with them. (I'll know if you didn't let her read this.)
I have attended three Fly-Ins with my husband, Don. He invited me to join him the first time simply by asking, "How would you like to go to Kansas?" I had never heard of a Q2 or Dragonfly and was not really interested in airplanes, but I love to see new places and knew he wanted to go, so I said "sure". There were 100+ people there, including 15-20 wives. I felt a little out of place because I'm not really interested in flying, but I had fun and made some new friends.
Three months later when my husband informed me that he planned to purchase a Dragonfly project, my world turned upside down. You're doing what??? I always knew he had an interest in flying, but I never thought he'd actually become a pilot, let alone build an airplane. Needless to say we had some very serious discussions as I came to grips with the reality of it. I wondered how other wives felt and decided to call Susie Richardson, one of the women I had become friends with at the Fly-In. Being able to share my feelings with her, wife-to-wife, made me feel a whole lot better.
I have come to realize that we "gals" have a lot to offer one another in the way of moral support. Therefore, at the 1997 Fly-In, Susie and I are planning a special agenda for the gals. In addition to having a lot of fun, there will be a "gals only" rap session. If you would like to help with the planning and/or would like to share your thoughts with me on why you don't attend the Fly-Ins or how you feel about your husband's project, or would just like to be kept in the loop, please drop me a note. I look forward to hearing from you.
After the first of the year I would like to write a 1-page "Gal's Gazette" which I'll give the ladies some options and ask for their feedback.
Debbie Stewart, P O Box 11929, Prescott, AZ 86304
I finished my Quickie ZN-LIN over 18 months ago and have had continual problems with engine cooling; and other items and was so depressed about the whole deal that I put everything on hold until I satisfied myself that the thing was going to fly. I have the Zenoah G50 (40 hp) free air-cooled engine fitted, aileron reflexer, extra fuel tank (3 gal) behind the seat; pneumatic tailwheel and cable operated disc brakes. The aircraft weight 320 lbs empty. I have about 8 hrs on it at the moment with about 5 hrs myself. I have a 46P and 47D prop designed by a colleague, using the Bate's prop optimizer program. This gives the following performance with a 1.8"1 belt reduction drive:
4000 rpm fuel flow 2 gal/hr 75 mph
4200 rpm fuel flow 2.5 gal/hr 80 mph
4400 rpm fuel flow 3 gal/hr 85 mph
4600 rpm fuel flow 3.5 gal/hr 90 mph
4800 rpm fuel flow 4 gal/hr 95 mph
5000 rpm fuel flow 4.5 gal/hr 100 mph
5200 rpm fuel flow 5 gal/hr 105 mph
5400 rpm fuel flow 5.5 gal/hr 110 mph
5600 rpm fuel flow 6 gal/hr 115 mph
Climb is about 600 ft/min at 80 mph. I have a fuel flow sensor fitted and designed my own electronic display system for EGT, CHT, RPM, fuel flow, voltage; engine time and OAT.
The engine is not reaching its maximum power, 6000 rpm, probably because of extra drag due to too large cowling holes and a slightly over-pitched prop. When I correct these items I expect to max out at 130 mph.
Things I did which I wouldn't do again:
1) Put disc brakes on. I think these are overkill. I originally had heel operated differential discs, but during one of the first high speed taxi tests these proved to be too fierce resulting in a broken prop after the Quickie tipped on its nose. I went back to the hand pull, non-differential arrangement that gives a better feel. They still raise the tail and need to be watched if used at higher speeds. Also they necessitated widening the wheelpants probably adding to weight and drag.
2) Put too much resin on the cloth. I am helping a friend build his own design composite machine and he puts half the resin on the cloth that I did. Also he vacuum bags which helps reduce weight and gives a smoother finish requiring less filling. He also used a resin that cures at 50 C so he can take his time doing layups.
Things which I would do the next time:
1) Be more careful when hot wiring cores. More accuracy requires less filling.
2) Sculpture out the inside of the fuselage more to give more space.
3) Increase the height of the seatback bulkhead by an extra 2" so I could wear a helmet.
As far as the engine is concerned the sorry saga of my self-induced trauma is as follows:
1) During the first flight EGT rose and partial seizure occurred resulting in an engine failure. This was on the downwind leg, so the test pilot landed without incident.
2) May subsequent flights resulted in engine overheating and poor running.
After hacking away at the cowlings to give greater air access it eventually dawned on me that the engine was running too lean because I had vented the carb vents out of the bottom of the cowls giving a different pressure to that seen at the throat of the carb. I had also put "frog eye" air scoops on the top of the cowls to improve carb breathing. These pressurized the cowls and made matters worse resulting in a lean mixture. Once I had sorted out these problems and tweaked the jet sizes all the temps came down and things ran well. That poor engine suffered at my inexperienced hands but has come through OK.
I must emphasize that it was my own fault and the Zenoah is a good, honest reliable engine. I had good advice and help from the folks at Tennessee Props and unlike some of the other engine manufacturers the fuel flow and graphs from Zenoah seem to accurately represent measured conditions. The total engine weight including exhaust and reduction drive came out at 70 lbs, some 10 lbs less than the Onan. The only thing I am not so happy about is the hand starting characteristics, I would recommend the use of an electric starter if you intend using this engine. The exhaust is the transverse option and fits across the Quickie firewall OK, and so remains inside the cowl with just a slight bump on the starboard side. I like to potter along at about 4200 rpm, as the engine is very quiet and smooth at this speed with reasonable fuel consumption. I'll send you some photos when I have cleaned my cowls up. If anybody is interested in using the Zenoah they can e-mail me for more information.
Keep up the good work.
Barry Charlton, Waitati Otago, New Zealand
Ed. Note: I have already contacted Barry about his display system and he says that as soon as he cleans up his notes he'll send the info on this to Q-TALK.
In August of 1995 I wrote a letter to you describing how I had destroyed the canard of my Q2 during "slow" speed taxi tests when it unexpectedly became airborne. Shortly afterwards I found a beautiful canard which had remained undamaged when the owner's Q2 lost power, landed in a cornfield and flipped over. I had to go all the way to Texas to get it, but for my purposes it was worth the time, cost and inconvenience.
It took almost one year to the day for the rebuild. Getting the remains of the damaged canard out was very difficult to do without damaging the fuselage structure. I tried very hard to get the new one in with the proper angle of incidence and spent several days agonizing over it before I finally glassed it in. I guess I got it right, because when I finally got up enough courage to fly it (12/6/96) everything went very well.
That's right! Fifteen years after the man drove up with the boxed kit and I spent the next few days inventorying and overcoming my bewilderment and awe at what I had undertaken I have at last flown my little airplane. This first flight was just around the pattern and then down to a rather bouncy landing. All of my instruments stayed well in the green, the engine sounded great, the climb out was very quick and uneventful. My next flight which will take place as soon as the weather permits will more fully explore the flight envelope. If there is sufficient interest I will gladly pass along what I learned.
Joe Morrison, Camarillo, CA
Ed. Note: Joe, first let me congratulate you on your first flight. And second, there's plenty of interest. That's what the QBA and Q-TALK are all about, learning from others. Joe, don't forget the pictures.
In the following article Brian Martinez continued to test fly his plane and trouble shoot some problems.
In-flight engine evaluation with Marvel Schebler carburetor substituted for Ellison TBI, I removed and replaced the TBI with the Marvel and performed a full power engine run. The propeller remained the PROPS, Inc. type previously used for flight-testing. Results for the ground test were as follows:
This indicated an increase of 2 inches of mercury in manifold pressure, maximum RPM was still 2300 when the carb was properly leaned.
Flight-testing of the aircraft was delayed completing cowling mods required to accommodate the Marvel and associated linkage notifications. Run-up was normal. During takeoff, the engine would not exceed 2300 RPM and again seemed to hit an invisible stop. Climb was approximately 90 MPH IAS with about 1500 FPM climb level speed did not exceed 121 MPH IAS.
The aircraft was post flighted which found a loose AIROQUIP fitting on the intake spider for the manifold pressure tap. During a subsequent ground run up, I examined the tip flexibility of the mahogany prop wondering if it is not permitting higher speed flight and is absorbing engine power. A Price prop is on order and expected in the next two weeks.
Prior to flight, vinyl connect tubing from total pressure vent tube to header tank vent tube was removed and replaced with Nylon Poly flow tubing. The vinyl tubing was installed during final construction of the aircraft over a year ago. Recent inspection showed this tubing to be swollen at the ends and somewhat pinched in the middle of the tube length. The main tank cap (which had a 1/16 hole drilled per plans) was also replaced with a cap having no hole. I was told to check out the vent line by Paul Fisher in a series of E-mail exchanges. The theory in this case was that the tank vent line was partially blocked causing improper tank pressurization compounded by the vacuum pressure generated by the hole in the tank cap on the side of the fuselage. This resulted in a leaning effect as velocity increased.
Extended ground run was performed to gain confidence that the tank venting was OK for flight. Max throttle RPM during takeoff was 2300 with the same PROPS, Inc. propeller as used before. This propeller was used for a data point in spite of the arrival of the new Prince unit. On this flight, however, the RPM did not roll off 50-100 RPM: Ambient MP reading was 27.5 in. During takeoff, 27 in. MP indication was observed for the first 2000 feet or so of climb. During push over the RPM climbed to 2450 or more and 150-155 MPH IAS was observed. The temperature at altitude was approximately 16?c for approximately 176 MPH true. This was the first indication of "in the ball park" performance with this aircraft. PROPS, Inc. propeller does work all right. I will repeat this effort on the next flight with extended performance runs to take a good look at the engine. Flight was discontinued due to low fuel. I am continuing to observe the sashay when transitioning to the ground with an apparent momentary control loss. Discussions with Gene Sheehan afterwards underscored observations made in posttest videos of rudder control loss with weight on the tailspring. Gene Sheehan recommends cutting the tailspring to lower the angle of the rudder control wires to the tailwheel bellcrank as the big tailwheel now absorbs all of the tail shocks. I am however inclined to install Maul springs in the present configuration as shorting the tailspring will change the ground angle of attack of the aircraft.
Preflight testing of the Prince 58", 68 Pitch propeller indicated maximum static RPM of 2300. This was consistent with previous propeller performance and was somewhat disappointing. Prior to flight-testing Maul springs were installed between the tailwheel bell crank and the rudder bell crank in order to prevent rudder flutter when weight is on the tailwheel. Right aileron play was also isolated to the aileron torque tube attach bolt. This bolt was tightened effectively eliminating the problem.
Directional control was better with the new spring arrangement as no sashay motion was noted at high ground speeds. Better control was also noted on the landing rollout. Upon reaching 7000 MSL a pushover was initiated which resulted in increased speed, RPM remained at 2500 to 2550 for over two minutes. After a resonant change, I noticed that the RPM went to 2650-2700. After throttling back to check the condition I resumed the max throttle position and approximately 2700 RPM. Airspeeds of 148 to 155 MPH at 8100 ft MSL and ground speeds from GPS of 169 kts with a tailwind. True airspeed was estimated to be 174 MPH assuming an OAT of 60?.
Takeoff was with fuel. Normal climb to 7000 ft. Noted smooth engine operation when properly leaned. Noted resonance in prop after reducing power from 2800 to 2500 RPM at 8000 ft MSL at 178 MPH TAS.
After fuel top off noted a fuel dribble from main tank sender terminal. This required 45 minutes of cleanup and seals the deal for expediting the replacement of the automotive type tank sender with the capacitance device.
Lots of oil on the bottom of the fuselage bleeding from the lower engine cowling. Still coming from the two case bolt locations on the top edge of the engine case. (Note: to try resealing with Permatex versus RTV.) Will have to reseal and clean. The new fuel sender is excellent; working well, though probably needs some adjusting for precision. Had some paint flake off on the bottom of the fuselage. Paint as well as primer slid off an area as big as my hand. I think maybe the surface did not offer enough tooth to hold on to. Will have to degrease, rough up, and re-primer. Beginning to note that on my landings I am finding myself imaging that the main wheels are wide extension of my legs. I am imagining that the mains are 5 feet out in front of their reallocation when I gently rock it back toward the tailwheel and ease the mains to the runway. This seems to work for me.
This next flight was performed with 25 lbs removed from the passenger baggage compartment leaving a total of about 27 lbs in that location. The passenger seat was uniformly weighted with 150 lbs. This led to a takeoff run of 23 seconds with liftoff at 90 mph indicated with moderate aft stick input VSI indications were as follows:
This is strange. Will have to do this one over, maybe it's real, maybe thermals.
Oil temp was at 230? today. About 85? this morning and climbing. Will have to really work on Sheehan's suggestion to remove the gascolator and duct air around the spin on oil filter. I am tired of watching those temps like a hawk. Due to the more aft CG positioning, only about 5? of up elevator was required to maintain straight and level. This is down from the usual 7.5? to 8?, which I usually have. This was well within the spring trim power and is a lot more relaxing than what was previously experienced. We are firming up to the idea of putting the aircraft in a two-week layup in the fall, cutting the main wing out and reinstalling it at a lower angle of incidence. Sheehan agrees that this is the way to do it. Still showing oil drips, but no noticeable sump losses.
Brian Martinez, Quartz Hill, CA
Q2 N124AT has been flying great. I've got about 120 hrs. on the rebuilt Revmaster and I'm really happy with it and I've learned something this last year. The aft cylinders on the Revmaster always ran hotter than I wanted them to, but the forward ones ran really cool. I tried reworking the cowling inlets to duct air in and air ramps on the upper cowl for smooth flow to the aft cylinders. It looks much better but did little for the cooling, I even tried restricting air flow through the oil cooler, but that didn't help, the oil just ran hotter.
I started thinking. What's the difference between a certified aircraft and a Volkswagen? Other than the obvious, a major difference is the placement of the exhaust ports, the former are straight down in the cooling airflow. The latter stick out fore and aft. On the Revmasters forward cylinders, the exhaust pipe flanges are exposed to the airflow, but the aft exhausts are in the dead spot behind the baffle. So I installed one-inch blast tubes and aimed them at the rear exhaust flanges. This time something happened! I got at least a 50-degree temp drop on those cylinders. Now the CHT varies between 325 and 350 degrees in cruise and up to 400? in a climb. From what I've been told, that's OK. A big benefit is that I can close down the cowl flap more than before and get more speed.
My friend with a Pitts and I are hoping to fly to Oshkosh together this summer so maybe I'll see you all there. He has 150 hp to my 64 hp but we cruise at the same speed. I'm glad I'm not paying his gas bill!
David Smith, San Rafael, CA
The Tri-Q-200 is coming along nicely. Everything is taking twice as long as I though it would, naturally. There have been a number of things over many years I've wanted to share with other Q builders, but I seem to take forever to get to writing it down. Most builders are probably way past ever needing this stuff but here goes anyway.
1) QCSM4 Spacer material: If you have a dire need for this elevator bushing stock and know that no one in the world has extruded Quickie parts for many years you can do this: order a foot of 03-06800 bushing stock (4130 steel) from Aircraft Spruce (ACS), take it to a machine shop and have the OD turned down to .930. It's a bunch heavier, but it is a relatively cheap and available substitute for something we can't find anymore.
2) Elevator actuator: In the event you need an elevator actuator, the shaft is 01-17100 bushing stock. Weld the shaft to an appropriate piece of steel strap and cut and bend it to original shape (assuming you have at least one original to go by).
3) Elevator torque tube bonding: Many people had problems getting enough slurry on the torque tube/elevator foam core interface during installation of the tube, which makes for a scary potential failure mode. I did one completely wrong, then inquired on how to do it better from a smarter friend than I. Position a cup of slurry under your torque tube and slather copious amounts on the tube as you are sliding it into the elevator core. The cup will catch the squeeze off. Now what to do with the harder one. You can drill a .5" hole three places along the leading edge of the elevator down to the torque tube. Drill a hole for an AN3 bolt thru the torque tube and into the elevator foam. Inject some slurry into the foam with a nylon syringe with a piece of Nyla Flow tubing on the end and insert a 2" long AN3 bolt thru the hole. Close out the hole in the leading edge with micro. The other fix is to drill a series of holes slightly smaller than the OD of the Nyla Flow tubing (for a tight seal) about 12" apart along the leading edge of the elevator down to the torque tube and inject slurry into the voids with your trusty nylon syringe and Nyla Flow extension. I managed to inject a disturbing amount of slurry into the elevator.
4) Trim wheel attachment: Forget the honked-up arrangement shown in the plans. Get a pop-rivet stem and drill a hole thru the trim wheel shaft the same size. Groove the trim wheel deep enough to accept the stem (assuming you used wood or something groovable). Slide the wheel over the shaft; nest the stem in the groove and epoxy in place. Instead of the silly cord called out in the plans for the trim lanyard, I bought some 1/16" flex cable from ACS and plumbed the trim system with the permanent cable instead. I used some bushing stock to increase the trim shaft diameter to provide a better bend radius for the cable and it works great.
5) If you have an O-200 engine and are as unfortunate as I am to have the pull cable starter and want to install a solenoid starter, here's the only two options I found:
a) Buy an MZ4214 starter from ACS for $170 plus a 653575 clutch/gear assy from Niagara Air Parts for $350. Only inconvenience here is you have to split the engine case to install the thing.
b) Send over and let B&C ream you out for his outrageously over-priced starter, if you can get it to fit. I understand from several sources it interferes with the engine mounts. Price: $800 plus $100+ for installation tools & kits. With this one you also have to hacksaw off the factory drive spline that you split the case to remove in option (a).
I chose option c) Rummage through old Q-TALKS to figure out how to install the stupid pull starter cable.
6) If you like the idea of a throttle quadrant, buy the three lever model from B&F (which is actually made by a real nice dude in Oregon names Dick Baxter) or ACS has one with a cast body. I used the B&F with one A950 & two A920 cables (ACS) and AN665-21R Clevis. The installation came out beautifully with this arrangement. The cable jackets terminate perfectly at the instrument sub-panel.
&) I spent a lot of time designing my instrument panel and creating the schematics. If you would like to save yourself a lot of time on panel design I would be glad to send you a copy. Add anything new you want and delete anything you don't want, but you absolutely must keep a good record of your panel wiring. When you throw the power to it and something doesn't work your schematics will be your salvation.
Gene Cash, 3111 Starling, Thousand Oaks, CA 91360
RENEW FOR 1997
U.S. RATE = $20
CANADA RATE = $22
OVERSEAS RATE = $26
Make checks payable to the: QUICKIE BUILDERS ASSOCIATION
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