Q-talk 5 - Q-2 TIPS
- Category: Q-Talk Articles
- Published: Tuesday, 30 June 1987 07:11
- Written by Jim Masal
- Hits: 2167
From Jim Masal, Editor
On a recent trip up here to attend a quarterly QBA Hangar 1 social, Mike Conlin's wife Bonnie began getting irritated eyes. Mike traced the problem to exhaust fumes entering through a poorly sealed belly board on the Tri-Q. Better check your belly boards fellas.
Also, be sure all your pulleys have proper cable guards. A couple years ago there was a San Diego Q-2 fatality that was traced to a cable coming off the pulley to a home-designed T-tail. A word to the wise...
From T. J. Wright
1. Pre-fab latches made for the EZ's or even Dragonfly can be adapted to the Q-2 canopy with a little thought.
2. Why not use the longeron as a permanent level reference? Instead of installing it at the angle called out in the plans just jig up the airframe correctly and install the longerons level using the same lamination schedule.
3. If you find it necessary to locate your battery in the tail, be sure to build a flat floor for the battery box in the tailcone. This spreads out the mass weight of the battery. You can use the easy to shape urethane foam, microed in place with at least 3 plys of 45 degree BID lapping onto the tailcone. Peel-Ply this floor for the battery box attachment. You can build a battery box by wrapping 6 or 7 layers of duct tape around the battery and glassing a box over it. Or use thin poster board as a form over the battery. Make a 2" thick bottom with 3-4 plys BID and a similar top, secure the top to the bottom. (ED. NOTE: Or...layup a couple of plys over the inside and outside of the box the battery came in. Then you'd have a REAL battery box.)
4. On doing your weight and balance - after you have weighed your ship with ACCURATE scales and measured your "actual" locations and are ready to enter the weight and balance chart in the pilot's handbook, DO NOT divide the total weight by the total moment arm. This was done by QAC in the chart. You will have wrong CG locations if you divide. This info provided to me by Scott Swing of Tri-Q Development.
From Scott Swing
On my Q-200 I used individual toe brakes and the same brake system that Gene Sheehan is using. After changing the ratios, I have enough brakes to stop the plane fairly well. These brakes are "Engenetics" (go-cart brakes) and are made in Dayton, OH.
I also made some changes in the baffling of the engine, as well as the cowling, in order to be able to operate the engine without an oil cooler. As the Cont. 0-200 comes off a Cessna 150, it has an aluminum shroud (baffle) that follows the bottom of the case and then flares down toward the oil sump. This is totally ignored in the baffling plans from QAC. Seems to me it's there for a reason and, if not used, could cause problems. Anyway, I used all the standard baffling except on the front where I cut the baffling to allow the air to flow down under the case out the sump.
All it takes from the standard baffling is a little cutting and bending.
Also, my air inlets are very small: about 12-15 sq. in. per side. They are D shaped right beside the spinner and have very large ramps with nice sized radiuses. So far the plane is performing very well.
Thought I would update you on C-GVZP since my last letter where I foolishly expressed optimism that I had finally ironed the bugs out of my Revmaster. After installing the Warnke prop and new exhaust valve seals, all seemed to be going well. I was cruising at 155 MPH on my way to Edmonton with everything working well when, as I passed over Red Deer, I noted some droplets of something on the canopy. I stretched forward and could then see a 1-inch wide band of oil streaming across the top of the cowl from the right air inlet. Fortunately, I was near the Lacombe airstrip and made an uneventful landing. Close investigation revealed hairline cracks in the crankcase starting about 1 inch below the oil pressure gauge connection and extending downwards for approximately 2 1/2 inches. One of these cracks had penetrated the oil pressure gallery. If this leak had not chosen to squirt out the front of the cowl so I could see it, the consequences would likely have been another broken Q2. I have 165 hours on the plane, and I enjoy flying it much more than I enjoy repairing the Revmaster so I have decided to convert to an 0-200.
From Myrl Bailey:
I had a spell of engine problems. I got a Revmaster with soft valve seats. Each 5-10 hour check found many valves had no clearance. After a few times of this I decided to go to the new heads. I was down 5 months awaiting this transaction then when I couldn't get it running right, I loaded it into a pickup and took it back to Revmaster. It ran no better for them until they installed intake manifolds with a different bend ratio. I may not be out of the woods yet. In 10 hours with the new heads, #3 exhaust has used up all its clearance twice. The airport manager calls my plane an on-going experiment. He may be right. I do notice a lessening of eagerness to tackle new problems.
From Bob Falkiner
I saw John Wirta's new Revmaster heads (regular, not the 75 hp). They have an insert (steel) through the head bolt holes. Looks like a fix to limit warpage/cracking in this area. Has this been a problem?
From Don Ismari
I had to pull my engine and send it back to Revmaster. The forward bearing flange was loose. After having the engine 2.5 months, it was returned and I flew it yesterday. After landing, I had lots of oil on the cowl, had trouble getting the POSA adjusted and found the valves were all off and in no particular pattern. A couple of fittings were not returned and I really question Revmaster's integrity and quality control.
(ED. NOTE: In a letter 7 months earlier than this one, Ismari wrote: I am currently on my 3rd set of heads. The first 65's were returned due to excessive valve creep. I replaced these with the 75 hp but later Revmaster replaced these too, after notifying me that they suspected problems with them).
The third set has 21.5 hours and the engine total is 60. I have had considerable oil temp and valve problems. I check valves every 5-7 hours and the exhausts are usually closed. Revmaster feels the shrouds will cure both the valves and oil temperature problems.
Since switching to 75 hp heads and larger intake manifold, retrimming the POSA is a problem. The engine is rich at idle, lean at full power and unknown in between. Eric Shilling told me I would probably have to extend the ramp with a file as far back as an inch vs. the .450 inches shown in the instructions. I did this and the mixture is much better. Apparently it is very difficult to get a linear mixture setting with the POSA for full throw of the throttle...the best you can hope for is to get close. I found out I was more or less a test case for the 75 hp/larger intake/POSA combination. I was not too happy.
While I was there, Eric and Alan tried to free up the starter problem...it will intermittently not engage the flywheel; it spins but won't throw the gear into the flywheel. Eric has had similar problems with his plane too. I thought they had it solved, but when I got back home, I found I still have the problem.
From Kim Andrews
Q-2 C-GVZP is having continuing Revmaster problems. The 20 amp alternator on the flywheel provides only 12-13 amps and valves need adjusting every 5-10 hours in warm weather.
We had a lot of trouble with our Revmaster. The camshaft went bead after about 50 hours and the case cracked in the oil galley where the oil pressure gauge is mounted. When we opened it up we found the #3 main bearing was cracked on the back side (the one with the thrust washers and bearing on it). They changed it from the back to #3. After over 342 hours now, the only original parts on this Revmaster are the crankshaft and accessories.
From Don Keizer
My engine was supplied without geared starter or carb. These arrived after several months without any instructions or hardware. The mags had 2 high-tension springs missing, there were no washer/gaskets under the hold-down studs for the head covers and the starter would not mesh with the ring gear. I pointed out to Revmaster that they seemed to have made the same mistake on mine as they did with the Olson brothers of Golden, B.C.: wrong ring gear supplied. I wrote that I was somewhat appalled at the workmanship gone into the assembly of this engine.
From Dan Judge
We have a problem installing the CDI ignition on newer Revmaster engines. We were not getting any spark and had to send the flywheel, electric ignition and harness back to the factory.
The engine manual had instructions only for mags. A call to Revmaster advised us to run the leads to the ignition just like we would a mag. Turns out that this overloads the circuit since each contact generates 300 volts.
Joe Horvath is working on the problem with the vendor, but advises that I use 4 toggle switches in the meantime.
(ED. NOTE: What the hell??? Are you saying that, like Don Ismari, you get to be the "test" case for the CDI? Nice to know you spent all that money for the honor! Several years ago I was told one of those backbiting rumors that I didn't pass on. It was told to me that Revmaster had a minimal staff which they augmented time-to-time by itinerant, passing-through VW mechanics, of which there are many in California. Doesn't this seemingly lackadaisical, loosey-goosey quality control make you want to believe it? Most reports I get paint Revmaster people as personable and reasonable in solving problems with builders, but comes a time when the problems ought to be solved INSIDE THE PLANT before collecting the money and shipping the (defective) goods. Is this becoming the "good 'ol American Way"??? Remember the ancient TV show BUNKO SQUAD? I always liked the line: "beware of the stranger who pats you on the back with one hand while he picks your pocket with the other".
We all make mistakes. But when a series of mistakes begin to show a pattern, they're deliberate; they may be unconscious, but they're deliberate. Deliberate laziness for example).
From Lenny Padios (by phone)
Lenny had his Tri-Q at Oshkosh but experienced much anxiety on the way home due to the puny performance of his Revmaster. Lenny is a service writer for an auto dealership, so he broke the engine down and took it to an experienced engine builder (VW engines). Lenny says the "heads are junk"; valve guides coming out, not much metal on the case where the guides go, valves appeared to be sandblasted old ones rather than new, looked like Swiss cheese casting around the ports, and the heads were cracked. His engine man felt the machining work done on the engine was quite poor. Lenny complained, Revmaster sent replacement heads, but 2 valves on these are leaking. Lenny got mad, didn't get a good response from Revmaster and so he marched on down to the local FAA and lodged a complaint. Even though the craft is EXPERIMENTAL, these engines are going on "N" registered aircraft, Lenny tells me, so the inspection branch staff called Revmaster. I'll tell you more when I know more sides of the story. Meantime, HEADS UP.
(ED. NOTE: In an earlier letter, Lenny did report heating problems that got better when he changed to 75 hp heads and intakes "you won't believe the difference. My CHT went from 425 to 350 on the hottest cylinder, #3, and to 275 on the others. I'm sure the reason is the intake manifold and not the new heads. You can see by the way they are designed you get better fuel distribution...oil temp dropped from 210 to 195."
From Paul Howe
Went to Rex Taylor's forum at Oshkosh on Friday morning and picked up a few tips on VW engines in general.
1. Baffling has to be tight.
2. There must be ample inlet and outlet area. Some aircraft have a climb angle that won't let them cool no matter what the airspeed is. A 2-psi minimum pressure difference must exist between the inlet and the outlet. A simple automotive gauge with a valve plumbed to each side can be set up and switched while climbing to check for this condition.
3. Torque cylinder heads in the specified pattern, BUT also alternate side to side. Seems pulling one side all at once wants to stretch the block that way. It's worth a try, just make sure all are 18 lbs.
4. Use EGT in setting the carb. Tie down tail, warm engine then run to top rpm. Start slowly leaning to peak EGT. Should only be 150 to 200 degree max. temp. difference. Any more and you will be short on climb power and cause overheating if too lean (carb needs the fuel for cooling).
5. Even with 3/8" fuel lines, keep 90-degree bends to a minimum. Low fuel flow causes leaning and overheating.
I later talked to a Q-2 pilot who said that Revmaster had a mod on one cylinder head hold-down stud hole. It seems they machine too much metal off the area near one hole and when the head gets hot, they come loose or crack. Anyone know about this???
One Q-2 had a split exhaust (one each side) with nothing crossing in front of the oil cooler. He said he dropped his oil temp. 30 degrees. I came home and made aluminum shields for my cooler and am going to the spin-on filter #PH 43, Fram, or the NAPA 1068. The spin-on is smaller than the original TP filter and it might let more cooling air in. It's worth giving up a few ounces of oil to me.
Can't say enough good about the WEST SYSTEM epoxy in finishing. Got both fast and slow hardeners that I combine to get intermediate times.
From Ted Eiben
1. A thin red line on the back of the tube used as a gas gauge for the header tank will appear wide where the gas is and thin above it.
2. If you have had clamps on the plastic tubing furnished for the gas lines for any length of time, tighten them again. The plastic seems to "ooze" out from under the clamps. When I first put gas in I had numerous leaks (lines had been connected over a year earlier).
From David Naumann
Don't buy a Continental 0-200 (pre '67) with a pull type starter and expect the starter to fit. The starter has a long pull arm that cannot be fitted behind the engine mount. A '67 or newer engine has a key starter which must be turned so the positive lead points down in order for it to fit the mag box (QAC Newsletter #22). The pull starter can not be turned.
(ED. NOTE: Also see McFarland's tip, QT #1 '87)
From Emil MirSepasy
Removable phenolic bearings for elevators as designed by QAC were too heavy for my taste, so I did mine with 3/8" phenolic as shown.
1. Drill for C20 only.
2. Cut bearing at line shown and assure a snug fit of the two halves.
3. Make 2 plates of .063 aluminum.
4. Hold bearing tightly, C-clamp the plates together and drill for two self-locking nuts and screws.
NOTE: Pay close attention to alignment of all edges.
From Bill Dillon
RE: 0-200 installations. The accessory box as per plans is an interference fit even with Slick magnetos. Having cut the header tank out one time already, I've decided to go with electronic ignition. Anyone know of a dual electronic ignition system for the 0-200? If not, I'll break that ground myself. The idea of pulling the engine to fiddle with the mags just turns me off.
From Scott Pihl
1. Relocate main fuel tank sump as far aft as possible for when the plane sits in a normal 3-point, the lowest point is aft of what's indicated in the plans.
2. Canopy Lip: Place duct tape around cutout in fuselage for canopy, then laminate the required BID with a Peel-Ply last layer, let cure. After cure use epoxy and wet flox, insure good squeezeout and clamp to required area with C-clamps.
3. If you decide to use the side-hinged canopy, DO NOT use the hinge supplied. I guarantee it will crack with 100 open and shut sequences. I used a stainless steel marine quality available thru Marine Hardware Supply. Size was 1 1/4"w x 1/6 thick x best length suitable to the curve of the fuselage. It's a bit heavier, but sturdier and worth the compromise. Streamline to the side of the fuselage with micro. (ED. NOTE: I'm told you should at least use extruded aircraft hinge. On extruded hinge, the hinge pin holes are one piece, not just bent around like on cheaper hinges).
4. Wing Laminations: Cut the spar caps 1" wider than plans as it makes them easier to maneuver, allows for misalignment and compensates for the loss of fibers due to edge fraying during all the handling the cap gets.
5. Wing Layups: Before laying up, barely tape a long strip of duct tape all along the leading edge to act as a drip guard. You can also layup the 45-UNI's lapping onto the tape then trim it after cure.
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