QuickTalk 27 - Q-2 REPORTS
- Category: Q-Talk Articles
- Published: Wednesday, 30 April 1986 07:11
- Written by Jim Masal
- Hits: 1103
QBAer Marc Waddelow has been working with other QBAers in the design of a "sparless" canard for the Tri-Q conversion. He has a package of information on his work available to share with interested parties. He writes about it: "I hold BS (LSU, 1979) and MS (Univ. of Texas, 1981) degrees in mechanical engineering. I make my living designing aerospace software. My stress analysis computer program, named Q@ANALYSIS, was written to aid in modifying my Tri-Q. My goal was to produce an aircraft with high altitude, 200 mph cruise capability. I selected a 150 hp dual rotor Mazda RX-7 engine that weighs about 70 lbs more than the 0-200, installed, wet. I designed 21" wingtip extensions to increase the aspect ratio and gross weight limit (1200 lbs) and used the computer to design revised layup schedules. First I ran the "design" program to see the loads and then I came up with a layup schedule and checked it with the "analysis" program. One or two iterations refined it pretty close. During the course of this analysis, I discovered some relatively high stresses and stress concentrations in QAC's main wing layup schedule. I exchanged several letters with Gene Sheehan, president of QAC on this subject."
(ED. NOTE: Sheehan was in strong disagreement with Waddelow's analysis but the exchange was interesting. While I ponder how much to print, you anxious hard-core experimenters might contact Marc for his data.)
Marc Waddelow, 350 Clemens, New Braunfels, TX 78130
From Art Dalke #2242, 1151 Lansdale Ct., San Jose, CA 95120
Help! Help! Help! N2432T is 95% complete but the ground angle of attack is 10 degrees. Gene Sheehan told me in a phone call that he "wouldn't even taxi a Q-2 with a 10 degree ground angle of attack." Seems as though he has identified the cause of the ground handling problems to be tailwheel liftoff before rudder becomes effective. He recommended that I correct the problem at the aft fuselage split joint. Simple trigonometry reveals I must cut out approximately a 2" wedge at this location to lower the tailwheel the required 5.5" to achieve the recommended 7.5-degree angle of attack. There must be a better way! Has anyone solved a similar problem? Sheehan said using reflexer will help but won't solve the problem.
From Mitch strong #2835
I am in the process of Tri-Qing my Q-200. I feel the plans are pretty easy to interpret if you read the gray areas several times. The only tough part is the bulkhead layups. The plans break up these into 8 separate layups with consequential sanding between each. I've done a lifetime's worth of sanding in the last 2 years so I did all 8 groups together. I couldn't stand up straight for a week, but it was still worth it.
There's no easy method for assembling the tire rims without pinching the tube; tire talc helps.
I have a 14" x 3/8" snake bit if any of you TQ builders are in need. (716) 344-269
From Philip Bryan #2768
I would not install the lower seatback bulkhead until after the canopy is installed and cut out. The canopy determines the location of the aft canopy bulkhead, which determines the location of the upper seatback bulkhead which mates with the lower seatback bulkhead. This is a case of double dimensioning for which any draftsman would get his knuckles rapped. My seatback bulkheads missed each other by a good 3 inches (nuts!).
From Bill Webb
I bought my Q-2 fully completed and flying; I thought I would save a lot of time and get flying quickly. The plane was loaded - IFR panel - had a good finish. 625 lbs and had a standard Revmaster with all the extras.
One week after I got home with the plane, my instructor (supposed 18,000 hrs, with 1200 in tail draggers) was taxiing down the runway and I think he brought the tail up (out of habit?) at about 40 mph. He cut power and the plane started a slow left turn off the runway. I suppose all would have been ok except that there was a water drainage ditch in his way. The right wheel caught it and came to a sudden stop, the plane went on its nose, and when it came down the fuselage broke in front of the tail. The right canard also broke halfway to the wheel and I lost the prop. The repair job has run $1000 for the wing and another $800 to get my engine checked and have the new heads installed.
From Mike Peay
I did not mount the FS 94 bulkhead when the plans suggested. Just fit it and trace lines for vertical mounting. This allowed me to mount my main wing without the possibility of enough room between the seatback and FS 94 for the wing, also saves interference problems with the center bearings (CS 7) while mounting the wing, and leaves plenty of room for glassing the fore and aft connector pads. Now I will just cut a hole in the FS 94 bulkhead for the CS-7 bearings and mount tip up against the main wing shear web.
The CS-6 phenolic bearing pg. 9-7 should be mounted just outside the fuselage skin, not just inside the skin as the drawing indicates (QAC agreed when I asked about it).
Installing main fuel tank drain - I wanted a drain valve hidden flush outside for protection and smoothness and I did not like plans approach to sand off inside layer in the fuselage for a depression.
I used 5-Min., flox, BID and parts shown as marked for siphoning water at lowest spot, aft end of tank. Get the threaded fitting at an electric lighting store or make one. Cap is from a propane cylinder.
From Ron Cross #2397
In QUICKTALK #8, David Robertson describes a better way to install the seatbelt attachments than the plans. I used a similar but slightly different method. For the outboard attachments, remove a section of the outside glass and foam so that a 1"x1.25" piece of 1/8" aluminum can be placed against the inside skin. Sand a transition so that the cloth will lay down smooth. Lay up 3 plies of BID 5"x4", position the aluminum plate, and lay up 2 plies of BID 5"x4" on top. Repeat for the other side.
The center attachment is similar except use a 2.5"x1.25" piece of aluminum and 5"x6" pieces of BID. Now glass the inside areas. On the sides, lay up: 2 BID 5"x6", 2 BID 4"x5" and 2 BID 3"x4"
On the center, lay up: 2 BID 5"x7", 2 BID 4"x6" and 2 BID 3"x5"
Use the 90-degree aluminum angle for the outboard attachments as shown in the plans, minus the plywood. For the center attachment, I took a 1.5"x4.75" piece of 1/8" aluminum and bent 1.25" of each side up to 45 degrees.
(ED. NOTE: An engineer might find strong cause to disagree with the use of bent 1/8" aluminum for the center seatbelt supports. Bending any metal causes microscopic stress cracks at the end. In a crash, two adults will be placing a LARGE force on this aluminum bracket. Worth considering.)
2. Page 3. Q-200 plans. My 0-200 engine has a 35 amp Delco alternator and Bendix mags. The magneto box templates and the firewall cutout template in the plans were not the right size. After many hours of cutting and measuring I came up with the following firewall cutout. Measurements show INSIDE dimensions. The box was made 6.75" deep to allow a half-inch clearance on the alternator. Also, the lower horizontal stiffner must be cut back for the alternator to fit. I think the joggle in the side of the plans magneto box would take a lot of time and result in weaker structure.
3. Page 17-1. Unproven Idea. Rather than use PVC pipe for the fuel inlet which will be in the way of air ducts and controls, I plan to fabricate a tube from fiberglass which will follow the contour of the fuselage.
4. Page 17-1. I located the fuel cap door so that the aft side was 4.5" forward of the instrument panel to allow clearance for instruments. The bottom side was located 3.75" up from the fuselage shell split line.
5. NACA scoops. I located the forward point of the scoop at FS 19. This allows enough room to route a 2" flexible tube anywhere on the instrument panel. The centerline of the scoop was located 2.75" above the fuselage shell split line. I used 4 plies of BID over a foam mold and then floxed the cured cloth onto the inside fuselage shell.
6. Page 18-1. To mount the instrument panel, I used 5-Minute to temporarily hold the panel in place. I put mold release (you could use duct tape) on the forward side and laid up 18 BID 9'x1.5" tape on each side, lapping 3/4" onto the fuselage shell. Drill two or three holes through panel and the cured tape for mounting screws.
7. Page 11-5. I didn't feel that aluminum axles would be strong enough, so I used steel tubing instead.
From Saylor S. Milton #2484
Except for the alternator/mag switch and starter button, I'm using LED indicating, rocker-arm switches for the master, fuel pump, strobes, etc. The advantage is that the LED light not only indicates that the switch was snapped to the ON position, but indicated also that the fuses or circuit breakers are OK. To hook up the LED correctly, a 4.7 K-ohm resistor must be used in series or it will burn out in a short time. Also, the right side (back view) of the LED terminal must go to negative (ground). If you require night dimming, a 10 K-ohm pot is optional.
Here is a first flight test report of a Q-2 flown by Jim Hayes on May 5, 1984 that exemplifies the kind of alertness and information gathering that we should all be aiming for on OUR first flights. Jim was not just boring holes in the sky.
FIRST FLIGHT TEST OF N4AN
BUILDERS: Irwin Abrams, Pete Nuding, Redwood City, CA
TEST PILOT: Jim Hayes, Belmont, CA (building Q-2 #2253)
THE AIRPLANE: Stock kit Q-2 with exceptionally smooth finish. Motorcycle type brake control for hydraulic brakes relocated to forward side of center control stick. LeGare T-tail on vertical fin with control lever about halfway back on left side of console. T-tail not connected to elevator trim control system. Empty weight 597 lbs, 20 gal. fuel and 5 lbs oil, 155 lb. test pilot, 25 lbs baggage compartment ballast. First flight gross wt. was 902 lbs with CG at 45.3" aft of datum point (aircraft forward CG limit is 44.3").
ENGINE AND PROP: Stock Revmaster 2100D, 64 hp, Cowley wood prop 56Dx45P.
LOCATION: Half Moon Bay Airport, CA. Conditions clear, 55 F, wind NW 15-20 with gusts to 25, quartering crosswind from the right about 20 degrees off the runway heading of 300 degrees.
THE TEST FLIGHT: 1540. Engine started easily on second try. Made several taxi runs at low speed. Ship steers well and handles 20 mph crosswind easily. Brakes smooth in application but not particularly strong. Brakes hold for runup at 1700 rpm but ship moves slowly at 1900. Turning radius seems a little wide but handles all taxiway turns OK even in crosswind.
1557. Normal Takeoff. Stick held full back until plane leaves ground, nose eased down until 100 mph for climb. T-tab set in level flight position. Full left rudder is required for torque and crosswind during takeoff roll, which was started in the overrun of runway 30. Liftoff was at the threshold line. First rpm noticed after liftoff was 2800, full throttle. Instruments reading normal in the climb. CHT 360 at level off and 320 one minute later. At the 3000' flight test altitude, air is choppy with brief smooth areas. Right wing heaviness noted but left aileron and left rudder handle it. Max level flight rpm is 2950. I had been led to expect 2950 on take off and 3200 in level cruise. IAS at max rpm is 158 mph.
1606. Throttle pulled back to 1500 and plane held level as speed bleeds off. Pitch bucking begins at 63 mph IAS with a gentle nod of the nose at about 4 cycles in 5 seconds. IAS 63 at top and 64 at bottom. Very gentle with lots of aileron control throughout.
1608. Cruise speed check at 2800 rpm yield 153 mph. Header tank fuel gauge is difficult to read. White would be a better background. Turned on fuel pump to fill header.
1615. T-tail check. Plane responds quickly to any movement of the T-tail. Throttle retarded to 1700, craft slowed to 100 mph simulating approach and T-tail placed full nose up. Descent stabilized at 80 mph and 350 fpm down. All control responses normal throughout.
1619. T-tail go around tried. T-tail full up, 80 mph, descent 350 fpm, full throttle was fed in. As the nose rose, forward stick was applied, the elevators easily overpowered the T-tail and a normal climb results. Amazing!
1622. Heading for the field, 2950 rpm at 2800' (full speed) results in a smooth running 166 mph. Enter pattern at 800' and 100 mph. Entering base, T-tail is set full up and plane slowed to 80-85 mph at 1700 rpm. Airplane stable in choppy air. Carb heat on throughout. Throttle closed over threshold, ease in full back stick and ship touches slightly tailwheel first.
From Ogden Knapp
One morning last fall I watched Scott Swing go out to a Q-2 (It had not flown and I would categorize it as average and adequately built), go over it thoroughly, make a few changes on the spot, and then about noontime watch him taxi test the plane, fly it around the Danbury Airport at 3500' for a half hour then bring it in for a trifle bumpy but better than average 3 point landing.
We first time builders with comparatively new pilot licenses build this Q-2 airplane with some dogged and nagging doubts in our minds about whether this "thing" will really ever fly - particularly when we read letters in QUICKTALK about builder frustrations, accidents, QAC abandonment's, shenanigans etc. You wonder!!!
You always have the feeling as you're building...is this little insignificant piece I'm putting together really going to save my neck someday??? Will this funny looking plastic hunk really fly around at 3000' with me in it??? Am I a pilot with enough experience and proficiency to fly this thing??? Maybe I'm too chicken???
The FAA endorsement of your plane is reassuring of nothing much since, if it doesn't fly and you break your back, it's no skin off some bureaucrat's bottom. An old cautious skeptic wants more than that.
SO anyway, it is comforting to know there's a guy like Scott around, to know he can check it out for you, suggest major and minor changes, approve it, and then most important of all, back up his approval by flying it around himself. Then you know you've built an airplane.
So the lesson for today is: if he can do it, it can be done...hang in there...stick with it.
ED. NOTE: Let's thank goodness that, at least in the sport aviation arena, we citizens have not been fools enough (YET) to pass over our own responsibility for protecting our own butts to the government. That's been a trend that's likely to reach us soon since we are being awfully careless about how we handle EXPERIMENTAL aircraft - I include designers, marketeers (purposely rhymes with racketeers) pilots and builders.
Further, I'm afraid this adolescent notion of "chicken" is putting far too many unprepared pilots into the air in EXPERIMENTAL aircraft...proving exactly what? That we are stupid and need government protection?
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