Q-talk 9 - Q-2 HINTS
- Category: Q-Talk Articles
- Published: Saturday, 30 April 1988 07:11
- Written by Jim Masal
- Hits: 3152
*************SAFETY OF FLIGHT ITEMS**************
FROM SAM HOSKINS:
A recent inspection of my Q-200 has brought to light a potentially fatal condition in my aircraft, which might be caused by the engine ripping itself from the airframe. After about 155 hours of flight, all four of my engine mounting bolt back-up plates (EM-2) on the aft side of the firewall, have grossly deformed from stress produced from flight. I have enclosed one of the defective plates for your inspection.
What happens is that in flight the engine pulls the aircraft forward via the 4 AN6 bolts. These bolts are mounted onto the firewall with a thin piece of aluminum which is over a pad of 4 - 4" x 4" BID. In the case of my buggy, the thrust of the engine tried to pull the heads of the bolts right through the firewall!! The wood of the firewall compressed, leaving an indentation, and the EM-2 back-up plate deformed around the head of the bolt.
To correct the problem I have made new back-up plates out of .090" 2024. Secondly, I am using a large AN970-6 washer underneath an AN960-6 flat washer to help distribute the load under the bolt head. I have also beefed up the firewall with an additional 5 BID, where the bolts come through the firewall.
If you are currently flying your Q-2/Q-200, check the back-up plates for any visible signs of deformation. If you see anything wrong, please investigate further and repair before you fly. If you have not yet flown and have wondered if this area is strong enough, (according to QAC plans) it isn't. Consider strengthening this area.
Sam Hoskins, Rt. 2 Box 456F, Murphysboro, IL
FROM BERNIE PETERS:
One day while fueling my Q-2 with 100LL I had a static discharge from my leg to the fuselage. I didn't think too much about it until I read where a guy got badly burned while pouring fuel from a plastic container. I don't have a static ground wire in my aircraft, but I am putting one in now, just a simple coated wire long enough to go down to the bottom of the tank through the filler neck with a ground lug at the fuel door.
FROM DON BAKER:
Don showed us at our Sun 'N Fun meeting a broken universal joint from the control system. Inspect yours carefully. A failure here could be catastrophic.
Bob Malechek called to report on his airspeed. He had gotten TAS's of 210+ but had always been bothered by a "twitchy" airspeed needle. He experimented with static line placement to no avail, but recently he relocated his pitot inlet to a position 4" behind the canard leading edge, 5 to 5-1/4" below the bottom (he was previously 7" back and 4" below) and about 45" from the aircraft centerline. It is level with flight level. Now his needle is stable, reads about 10 mph lower, and he feels his flying is a bit better since he can now count on the accuracy of the readings. He took an hour's cross country alongside a Twin Comanche and was able to compare high, medium and low speed ranges with good accuracy. On the trip, Bob noted once again that careful adjustment of tail height (i.e. getting it on the step just right) meant a few more mph.
Bob has changed over to Champion REM 37 BY spark plugs. They are 1/4" to 5/16" shorter (better cowling clearance) and the firing tip is extended into the cylinder 1/8". Bob says Lycoming solved lead fouling with this extended tip but Continental does not approve the plug. Bob checked piston travel to be certain at TDC the plug would be clear. He's happy with the performance of this plug and thinks the engine runs better so far.
Malechek had the bearings on the fat tailwheel wear out after 100 hours (he gives lots of rides, giving the wheel a workout). He says these bearings are of lower quality, but he found that the original tailwheel bearings were better and that they fit the fat wheel too.
Also on bearings, Bob found he could very carefully remove re-pack and re-seal his main wheel bearings. He thinks this should be done annually.
Bob was getting some slight control stickiness that made very slight trim adjustments at cruise irksome. He tried several lubricants for the phenolic blocks from wheel grease to some so-called "space age" stuff from the auto store. Nothing worked to his satisfaction until he tried something from the kitchen - his wife's PAM worked great! We talked about the man/machine interface. Bob felt he knew how to fly the Q-200 at 50 hours. Then he got some scares. He REALLY felt he knew his bird at 100 hours. Now at 240 hours he's resigned to the fact that full concentration is required on landing or else he can lose it in a microsecond. He got a pucker even recently when he paid too much attention to the leading touch and go-ing Cessna.
I recently talked to Charlie Harris of CO who got more than a pucker from losing concentration. In QUICKTALK 26 he reported a flip over at his 3rd hour of high-speed taxi. Disheartening, but he continued to work diligently and got the plane back together. He successfully flew and accumulated 20 hours or so until one day he was in the pattern with a training Cessna and got into a radio "discussion" with a mouthy instructor. Result: lost concentration, lost landing and another long repair job coming up. He'd like you to learn from his mishap...and give renewed thought to a Tri-gear conversion.
We're a pretty long way down the road in the Q-2/200 experience. And we have a pretty long list of accidents; long enough to conclude that far from being any easy aircraft to fly, this aircraft is more than usually demanding of a pilot's skill and training. Bob Malechek cites one of the unusual quirks of this design. A conventional aircraft generally can land or lift off just at its stall speed. Bob's plane stalls at 65 mph, but there is no way in hell he can make a normal approach at even 70 mph. The sink rate at that speed is 1500 fpm and there is no stick left to flare just before the hit. This is unexpected by the typical Cessna or Piper driver. Furthermore, even at higher approach speeds, we do not have pure elevator control. Like the canard, the elevator is doing 2 jobs at once and when, at some magic moment on landing it converts over to a flap device, the pilot better not decide to push the nose over to gain speed. If he does, the flaps will suddenly come off, lift will quit and the pilot will find himself in control of an increasingly violent pogo stick. Thus the need for extra concentration on landing.
From Jan Bowman
I now have 20 hours on my Tri-Q conversion and it is excellent. Landing is relatively easy and the pucker factor is way down.
I found that performance, particularly climb, was marginal at a gross of 1150 lbs. with my 75 hp. Revmaster. I was unable to exceed 3100 rpm at full throttle. After trying everything else, I borrowed a prop from Mike DeMuth and replaced the Cowley. Static rpm increased from 2900 to 3100 with a top 3500 rpm. Climb at 3,000' increased from 300 fpm at 105 mph to 450.
After giving Mike the data, he made me a new 54x44 prop that is outstanding. Top rpm is the same, but climb is close to 600 fpm and the oil temp and CHT are now solidly in the green. Mike modified the prop profile near the hub to get more airflow to the engine.
I heartily recommend Mike DeMuth for propellers (phone: 301-461-4329) and the price is right.
N5585N pitch bucks at 75 mph indicated and landings are made at 105 IAS on base, 100 final, 90 over the numbers and 80 at touchdown. I put a Tri-Q speed brake on but don't see a lot of effect from it...maybe because it only opens 3" and is 21" wide.
From Bernie Peters
For a while I was landing with full up reflexor. After expanding my envelope to gross weight, I find this is no good as it puts the tail too low and increases the landing speed and that ruins ground handling. I am now landing with 2 degrees up reflexor which seems much better.
Also a reminder: the Revmaster oil level should be checked in flight level to avoid over servicing the oil.
From Don Baker
It worked! Finally, after all that work, my last 3 landings have been perfect! Ground handling is no longer a problem. Here's how I did it...
Installed vortex generators to increase lift (???-ED.), and speed brake to shorten ground roll.
Installed new single leaf tail spring (customer built for $16) to get angle of attack to 7.5 degrees. This spring is much softer than the glass original and makes it more compliant with the runway - much less bounce and porpoising.
Installed rudder actuating bracket a la Chuck Elliott to get rid of slack in rudder cables.
Added 2 inches to the vertical stabilizer and the rudder. Credit Jack Harvey (Aug. 1987, p. 15).
Learned how to fly the airplane. After soloing years ago in a Champ then 3000 hrs. in high performance aircraft, I'm still learning...I credit Duane Swing's 10 pointers (QUICKTALK #17), Don Short (Q-TALK #7), Danny Rundell of Louisiana, and my instructor here, Terry Camp, on the landing technique. Here's what works for me:
Get the speed brake out, reflexor set trailing edge 1/4 inch up and slowed to 100 on downwind. Slow to 90 on base and hold that on final over the fence. With speed brake and a Warnke prop, this takes 2500 rpm! I allow a fairly long final to get that speed firmly set and established. Flare level. Eyes never leave the far end of the runway. Immediately come back on throttle until a slight sink starts. Lock the throttle. Stop sink with slight back stick. Keep doing this until she settles gently to the runway in close to a three-point attitude. Keep rudder cables tight. Chop throttle. Go very light on the brakes. Don Short gave another good piece of advice. If there is ANY problem with that approach and touchdown, i.e. speed not constant and correct, flare too high, bounce and/or porpoising, etc., etc., make a full throttle go-around and do it again. Don't try to straighten it out in the ground roll. He said that your attitude should be that you enjoy flying it anyway, so keep flying it until you get everything right. I had 6200', but easily made midfield turnoff every time.
In terms of the airframe mods, I'm sure they are all important, but that rudder extension is where you really get control. It's going to be a fun airplane!
Don Baker's Mod
ED. NOTE: Don, promise me you will review all this in 100 hrs. and tell us if all this still holds. I'm still learning too!
All this good advice must be cautioned with the thought that in the real life world of changing weather, changing locales, changing traffic, etc. there are very strong forces out there that distract us and push us into altering our safe, established patterns. Don't fall for it or you will get a BIG bite in the butt!
SERVICEABLE FUEL TANK SIGHT GAGE
After my original main tank sight gage failed to operate (the float was stuck to the bottom of the tank), I decided there must be a better way of installing a simple sight gage that could be serviced. The above drawing shows my solution to the problem.
The float is made of three layers of 1/4" white foam cut in a circle so that the float can pass thru a 1/4" N.P.T. threaded hole in the top of the tank. Do not bother to coat the foam with epoxy, as it will just add weight. (I've had a sample stick & foam submerged in a bottle of 100LL for three years with no apparent de-generation of the foam or stick.) Make the stick as light as possible to improve accuracy of the gage. It is a good idea to test the float so that you have a good idea how much fuel is left in the tank when the gage reads empty.
Install the drilled & tapped steel fitting in the top of the seat tank using the same technique as the installation of the drain for the seat tank as described in the plans (flox, covered by 2 BID tapes).
The 1/8" coupling helps to stabilize the float stick & prevent it from falling over. You must make the stick long enough to touch the bottom of the tank and still have the tip of the stick just above the top edges of the coupling.
The clear rigid PVC pipe can be threaded inside by using a 1/8" N.P.T. tap, to tap the PVC, chuck the tap in a vice and begin threading the PVC onto the tap. Rotate the PVC 2 or 3 turns onto the tap then rotate it back off to remove the excess material. Continue repeating this simple process being very careful not to force the cutting too quickly as the PVC will split. Tap approximately 3/4" into the pipe for sufficient holding strength. Remember to use some pipe thread compound when assembling the sight gage.
HEADER TANK SIGHT GAGE
NOTE: FUEL LINE CLAMPS NOT SHOWN ON DRAWING.
For my header tank sight gage I tapped both ends of a piece of clear rigid PVC and threaded a 90 degree 1/8" NPT x 1/4" barbed connection on both ends. Remember to use pipe thread compound to properly seal the sight gage.
DRAWING NOT TO SCALE
Drawn by: Phil Haxton, 238 Robbie Lane, Marietta, GA 30060 (404) 432-5373
Daniel J Judge #2876 - (406) 873-2249/5219
N31DJ now has 26 hours. I have flown her up to 12,500' and at 7,500' have had a TAS of 180 mph. She is equipped with a Terra TXN 960 TRI Nav C radio, combo CHT/EGT, manifold pressure, Dacon hour meter and Whelen A600 strobes. As budget can afford, we will add gyros, transponder and loran. We have the 75 hp Revmaster engine. Weight is 579 lbs. At the five-hour mark, the tailspring broke. Devine intervention-averted disaster. I would like to share my solution to the problem.
In order to get the desired 7.5-degree AOA, it was necessary to change the tail wheel. Q-Talk had lots of ideas and I adopted them. The only problem is that the rudder cable was still connected to the tail wheel and when I "crashed" this rigging resulted in loss of rudder.
The decision was made to install a "real" tail wheel. We chose a J-3 leaf spring ($30) and used the short and bottom springs, a 4" Santa Paula non-swiveling tail wheel ($90) and two compression springs plus additional 3/16" cable.
The rudder cables now go directly to the rudder. Separate cables with the compression springs now join the rudder cables at FS 120 via small cable connectors (ALA C-170). Turning radius has suffered a bit but take off and landing control are vastly improved.
Begin by removing the tail section. Turn it upside down and brace it well. Cut off the old spring about 2" aft of the line that comes down from the leading edge of the rudder.
Next, cut a piece of 1/4" flat steel 1.25"x10". Drill a 7/16th hole centered 1" back from the designated front of the flat stock and another about 4". About 2" from the end, drill another. Now before the end, you'll want to weld on two "side boards" to keep the springs from sliding sideways. These pieces should be .25 x 1.25 x .8". Weld on a 7/16" nut over last hole.
Then, route out the bottom of the fuselage to receive the flat mounting stock. The "side boards" should extend past the fuselage. Lay the mounting stock in so that it is flush and centered. Do it well so that your tail wheel will be perpendicular to the ground when done!! With a marker, mark through the forward holes in the stock onto the foam. Drill out the foam with a 1" bit to depth of 2.5" and 1.25".
You are now ready to mount the flat stock. Mix up some flox and fill the bed and the holes you've made. Lay the flat stock in and screw in appropriate length lag screws. Cover the whole area up with four BID glass. Go up the side of the vertical stabilizer at least 1.5".
After the layup has cured, mount the tail wheel assembly. You'll have to drill two new holes for the Nylaflow tubing for the rudder cables in front of the rear bulkhead. The old holes will work well for the tail wheel cables. Be sure to do a new weight & balance. You will have a net gain of at least two pounds.
All of this will get you better control, positive rudder actuation and look like a real airplane. The tail wheel can be ordered from Aviation Products, Inc., 114 Bryant Street, Ojai, CA 93023
Bob Falkiner Q-2-2015
I was very disturbed to read of your accident in the QBA and as a result have been thinking quite a bit about what it all means when it comes to the control strategy of Q-type aircraft. By the way, I'm glad you're still with us - less determined men would be tempted to give it up.
The question I have is - why can't the Quickie elevators be actuated differentially like flaperons to give better roll authority? I keep hearing about +/- 2 degrees of rig being essentially full aileron travel. This combined with the rain problem (especially differential rain problem) seems to put the craft into the "highly uncertain" category (ref: Masal Sept87).
Translation: if your elevators had been rigged to deploy differentially about 2-3 degrees in concert with the ailerons, would you have been able to arrest the roll?
Before anybody jumps on my case for tampering with the design, I would like to point out that the Q-200 has about +/- 1.25 degrees elevator differential (probably inadvertently) built into the design of the LS-mod canard linkages. You have to look carefully at the geometry of the linkage to see where it comes. Basically the distance between the two Q2CSA8 arms (3") is greater than the 0.75" distance between the two rod ends on either side of the control stick. This causes a small deflection in the same direction as aileron travel when you apply side stick. I did some careful measurements on mine at full aft stick, and found that the trailing edge of the elevator moves 22/64" from full left to full right stick. This translates to a 2.5-degree deflection, or +/- 1.25 degrees from neutral stick. The elevators have about 4 times the area of the ailerons, so this small deflection is probably equivalent to +/- 5 degrees of aileron (i.e. not a trivial amount).
Can the Quickie linkage be modified to include a similar amount of differential? The climb rate at full deflection may suffer, but that may be preferable to inverted landings. It will be more difficult with the "one driven and one slaved" elevator system in the Quickie, but I'm sure that a good differential linkage can be devised by somebody smarter than me.
All of the above begs the question - Why are ailerons needed on a Q-craft at all? Could not all the roll control come from differential elevator with a significant saving in weight and complexity? Even more daring, why not interlink the elevator and ailerons to give the similar relative lift from main and canard throughout the flight envelope. Some movement forward of centre of lift with aft stick is necessary to control pitch, but how much is enough. The need for air brakes to reduce max pitch on landing (at the expense of speed) seems to indicate that the existing control strategy is not optimized for the basic design.
I do not have the expertise or experience to pursue any of this, since there are other problems to think about, such as canard first stall and aileron/elevator stall. I hope its food for thought for somebody out there.
Like many others, my Q-200 project had been in a stalled state for longer than I care to remember through a combination of discouragement and time limitations. Two years ago I purchased the 0-200 engine for the project in the form of a Cessna 150 Texas Taildragger and had grown to enjoy practicing my taildragger abilities more than locking myself up in the workshop. My sincere interest in the Quickie had never really left, only the sense that I would ever really finish.
I flew the "project engine" to Oshkosh 87 and attended the QBA evening meeting and returned somewhat revitalized but it was what happened one evening in late October that really relit my fire. Mitch Strong took it upon himself to look up the names of Quickie builders near him and contact them to lend support and encouragement. His Tri-Q-200 had first flown this spring and, receiving his call was interesting and welcome. However, it was the words he spoke towards the end of our hour-long conversation that really perked up my ears. "I'd be glad to give you a ride in it if you get a chance to come to Batavia before it goes home for the winter and some finishing work."
The next Sunday morning my 150 and I sat beside the runway at Genesee County Airport scanning the horizon for a strange-looking airplane. A short time later he returned and we spent several hours talkin-n-gawkin at his plane, which had some 75+ hours on it then. Then came the opportunity to fly with Mitch and the chance to actually get 20 minutes of stick time in his exciting airplane.
My workshop has since been reorganized and a fresh supply of Safe-T-Poxy ordered. I've been reviewing my plans and am nearly ready to begin the main wing layup. Thanks to a considerate fellow builder my Q-200 once again seems an attainable goal.
To you fellows who have reached the project's end, please do an immense favor for those builders like me who could use the shot of enthusiasm which only comes from seeing the various bits and pieces laying around our garages and basements actually flying. Better yet, if you feel sufficiently confident of your abilities and are willing to not succumb to the litigation-induced fear of increased exposure, give the guy a ride. It will provide an invaluable boost to his project and will almost surely provide you with a fellow Quickie driver down the road sometime.
I'm back at work on Q-200 #2794 once again and will eventually see you guys on the Oshkosh flight line. Many thanks, Mitch Strong.
Lynn Faulkner, Manlius, NY
I know it's hard to find too many Gene-fans, but had the legal system not swallowed him up we might have more builders out there. I like the fact that he keeps going out to the CAFE 400. The results sure help the Q-200 builders. Surely other pilot-builders can compete. They don't have to win or be engineers and get every last mpg to do a creditable job.
Phil Kelly, Miami, FL
From Tom Gordy - Carrollton, TX
POST CURING THE CANARD STRUCTURE (PG 10-10)
I cured my canard in a solar oven. It was 3 1/2' tall, 4' wide, and 20' long. A frame of 1x2s nailed together (5-Minute was not strong enough) and covered by a sheet of black plastic (purchased at a garden supply store) which was held in place by sandbags on the ground and a few staples fired through duct tape reinforcing at the corners was all that was required. The plastic will stretch as it gets hot, so a few crosswise strips of tape inside will help it hold its shape. A meat thermometer stuck through a duct tape patch can be used to monitor inside temperature if you would prefer not to be in there feeling the canard surface. Excess heat can be allowed to escape by lifting an end flap. Putting a circulating fan inside will only lower the temperature. Any holes or tears in the plastic will cause large amounts of heat to be lost. No maximum temperature is given in the Q2 plans, but I went no higher than 165-170 degrees (F). Rutan's EZ plans say a black painted surface can get to 180, so I felt this was safe. Achieving these temperatures should be no problem. Be careful with the temperature. EZ plans say their foam is damaged by temperatures above 240 degrees. This oven not only saved me a lot of painting and cleaning up, it also saved me the job of turning over a red-hot canard and the probability of accompanying loss of skin.
Pre-bending the longerons (page 8-5) seemed hopeless until I realized my kit had 3/4" spruce longeron material. I ordered some 5/8" and all went well. I did use a 3/4" longeron on the right side to help take canopy loads and give me more space to mount the hinge. Some builders have cut 5/8" plywood to curve with and fit the fuselage. This, of course, avoids any bending on longerons.
JOINING THE FUSELAGE SHELLS - PAGE 8-4
I took advantage of sturdy jigs and turned the fuselage on its side to make these layups. That way, they were all horizontal layups. I also cut out the canopy hold before doing the inside layups. This allowed easy access to the inside tapes. I am 6'1" and 220#. Climbing inside the fuselage through the seatback and FS95 bulkheads was not an eagerly anticipated task. Also, climbing into the tailcone can give a very claustrophobic feeling as well as being hot and stuffy. I used the exhaust from my shop vacuum to furnish ventilation. Just be sure to remove the fan motor from the can or you will get a lot of dust with your air. If you think this layup (inside tapes on the tailcone) is no fun, just wait until you get to the lower main wing attach inside layup. You're gonna love it!
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