AA5BY

I promised a picture of how the stock Zenoah muffler worked out. Comparing the two sides... the starboard side has the velocity stack within the dummy engine and the port side has most of the dummy engine discarded.

rowdyjoe

My Feedback: (9)

Hey, that's a good looking bird ...and a familiar on too.
Looks like the WX folks got it wrong again for today. The wind was up a bit too much for first flight of my Yak so, I stayed home and installed the new carb on the SW engine.
It was a perfect fit and when I turned it upside down Iwas able to attach the longer throttle arm Iordered along with the carb ($2). I rerouted the throttle rod and eliminated one servo. My choke servo (mounted in the fuel tank compartment) is now the throttle servo and I rigged a manual choke in a unique way. Wish Ihad thought to take pictures before Imounted the cowl. I spent about 9 hours on it today making the modifications and getting the engine tuned with the new carb ....which works FAR better than the stock carb. That was $32 (+ shipping) well spent. It idles fine and has a smooth transition and starts easy when warm. It took a bit of patience, needle fiddling, and prop flipping to get it to start and stay running but, it's running great now with the cowl off. Tomorrow, Ineed to test run it with the cowl on. I hope it runs fine as the cowl is difficult to get on and off with my manual choke in the mix now.

Concerning the Yak cowl and the pressure issue; I think it would be easier to solder a copper tube to the carb plate and run a piece of fuel tubing into the fuselage to prevent the variations in pressure affecting it. Baffling would add weight and she's balanced right on the money now.
I ran the engine with the cowl on yesterday and it seemed to like it fine but, all bets are off when she gets airborne and unloads after takeoff.

The weather looks promising for flight tomorrow ...winds 5 to 10 mph in the afternoon and temps in the high 50's. I'm going to try hard to fly something. I need a break from the building bench.

RJ

AA5BY

RJ... very good on all, wx window looks ok for today unless wind kicks up. Y'all are on the edge of the West Texas prairie so generally see a lot more wind than we do, though we have noted our winds have increased in East Texas over the last several years.

We have a bit of work scheduled at the field at 11 am but it shouldn't take more than a couple of hours.

Best of fortune with your flying. Have fun!

AA5BY

My Spacewalker has flown. It was however an unusual outing. First on the list of things to do was range check with and without engine running. I took my gas can and headed out for the non powered test and went more than an adequate distance out and set the can at that point to compare how much range was lost with engine running. With the engine running, I reached within five paces of the gas can and still had it when tension was lost on the up elevator gimble. So, I had range, but had an inoperable transmitter.

Normally I don't mess with such stuff at the field, but decided to see what the issue was with the gimble. A pin had come out of a hole so it was pressed back in and will get more attention later. The radio surgery took a half hour.

Now with the engine started and ready to go, the ailerons start fluttering. A quick check seemed to indicate that the problem is that the aileron servos (Hitec 645MG) are getting desensed by RF from the transmitter with a fully extended antenna in close proximity (3-4 feet)... so I'm OK with flying.

Take off run goes well, but as soon as altitude is reached and stick relaxed the plane needs a good bit of up trim. Once the up trim is added, it now has some roll and needs aileron trim, which at the moment struck me strange as it didn't show any initial roll.

Flew the patter several times, did a few loops and rolls and then took it high to check low power characteristics... not much of a power off glide slope but it would slow to a crawl without tip stalling. It has a slight bit of aileron up trim at low power and ought to establish some sort of power off glide slope... but it didn't and knew that when landing it would require down elevator to get it down.

The CG was a half inch forward of that called for. Getting high again, at half throttle and trimmed for level flight, it was put in a 45deg down slope with hand off stick. It curled slightly towards the canopy so was slightly nose heavy. My impression was not a full half inch worth but it is possible.

As expected the landing was a bit difficult because of its reluctance to establish a hands off glide slope.

On the ground, as soon as it was back close and off the grass, I realized it had lost its tail wheel. A search discovered it where the plane had turned around (less the springs and mounting screw).

Next, I noted that the port elevator didn't follow the trim change of the starboard.... ahh, that was why almost all the trim was needed on elevator and why roll seemed to be an issue only after trimming pitch.

The engine ran great and otherwise the flight went well.

While it is too soon to tell for sure, there might be a slight decalage issue. Power on and power off trim are not the same. My Yak suffered this exact problem and needed an incidence adjustment. First task however is to get the elevators trimming together. Then get CG where it should be based on in flight CG test. Last, wing incidence will if needed get trimmed to bring elevator to neutral and see if that doesn't produce the same trim for power on and power off. My previous experience is that when the elevator is in neutral trim... both power on/off trim are good.

The CG check we did today at the field was an upright test, I'll also put it on the CG machine inverted to compare. The upright test showed it a half inch forward needing 2.5 oz of tail weight but again, the in flight test didn't produce a lot of curl up... so I'm not sure the CG is off that far but it could be.

My guess is that the CG is not off a full half inch in part because inverted flight took the normal touch of down whereas if nose heavy, inverted flight will often require a lot of down. I also believe it very possible that the wing needs a very slight bit of positive incidence. I say wing because the stab is glued and fixed, whereas the wing is easily adjustable. We'll see.

I'd enjoy hearing what others have found trim wise. Is your elevator neutral to the stab? Are power on/off trim the same? Do you have any issues with the plane setting a proper landing glide slope?

rowdyjoe

My Feedback: (9)

Arlyn,
That's Great !!!!! Congrats on a successful first flight.

Mine flew today too. It was twitchy in pitch so Ilanded after about 5 min. (it took 4 approaches) to remove weight and rebalance. We took off approx. two ounces of the lead Ihad added to the tail and she flew straight and true with just a couple of clicks of elevation and left aileron. Inverted flight took almost no forward stick. ILIKEit like that.
I must rework the throttle servo and linkage as I couldn't reduce throttle enough to slow her down for landing. She's a real floater and lands at a very slow speed compared to my 55cc bird.
I'm going to like flying this one. She handles very nicely and will be a great relaxing bird to for casual flying. Ithink I'm a bit over-proped too. I'm running a 17x8 and RPM at high throttle was only 7400. The engine is also running rich and I'll have to lean that out too. I set it up a bit rich thinking that as she unloaded in flight it go a bit lean but, Imust have over done it.

I'm happy with the way she flies and will work our the throttle issues. I'm very encouraged to get those little issues fixed so I can fly her again.

The Yak is another story. She wouldn't run very well for me at the field. I got her started and running but, she kept dieing at idle and didn't want to risk a dead-stick. I believe the adapter is leaking air and I've ordered another one. It will be here Monday and hope it will resolve the issues with that carb when I install it.

Congrats again. Hope you get all of the issues with your bird worked out.

Added: I believe that the left aileron trim was needed due to the right and left elevator halves not being correctly aligned. Ididn't notice that they were slightly off until after the 2nd flight. A simple linkage adjustment should cure that issue.
Did Imention that Ireally like this plane? She looks great in the air and on the ground.

RJ

AA5BY

RJ... glad to hear you also got your maiden done on the SW. Yep, it takes a little effort to get things fine tuned and sometimes corrected.

My efforts last night included, making a shouldered bushing for the tail wheel (on the lathe) and getting the wheel assembly re-mounted. Some wire linkages were installed until some springs are found. Some where I've got a batch of springs, but couldn't find them last night.

Moving the elevator slave to mix 5 as only 5&6 carry the master trim to to the slave.

The gear switch was programed to trim some down elevator for landing. It will be tested up high to see if it provides a better landing glide slope.

One ounce of tail weight was added to tail. At the field it took 2.5 ounces to get close to the posted balance point but as I've said, I'm not so sure that position isn't slightly too far aft. Your comment about taking some weight off helps me think my conclusion might be right. Another in flight balance test will tell a lot and if it calls for more... it will be added.

After getting the back of the transmitter off to do a more permanent fix on the gimble problem, I was crashing (needing sleep) so put that effort off until today.

The tail weights were stuck to the bottom side of the tail wheel strut with room on the top for another ounce. When the amount is settled on, they will get heat shrink to hold them from coming loose.

Your comment about pitch sensitive agrees with my observations. I did the full one inch elevator throw for sport flying using 45% expo and found the pitch to be OK but wouldn't want any more. It just occurred to me that with moving the CG back some more, it ought to get a slight bit more expo. It took almost all of the up elevator trim on the first flight to get trimmed, but that was of course due to only trimming one elevator half... I've corrected that issue as noted above. I'll move the expo to 50%

It took me a second landing approach because of the inadequate glide slope and the landing wasn't that good. It is very hard to get good landings from a plane that doesn't establish a proper power off glide slope. I'll not be happy with the plane until the issue is corrected.

Might get another chance to fly it again this afternoon.

edit... a drop of CA on the pin in the gimbal... tugged on it pretty good and doesn't come out now... so think it will stay.

rowdyjoe

My Feedback: (9)

Good morning.
Sounds llike you have a good handle on all of your tuning issues. Iknow you'll have those worked out in no time.
The pitch sensitivity on my bird went away after Iremoved the weight, limited elevator travel a bit more, and added a bit more expo. Ihad too much elevator travel and loops were about 10 ft in diameter at half stick It's much better now.
My glideslope issue was due to high idle speed. However, I was able to reduce power and establish a nice flat approach even though she was too fast. Fortunaltely, the transition between concrete runway and our adjacent grass strip is smooth so, Ilet her complete the roll-out in the grass to pull her to a stop.
She didn't want to steer on the ground very well and I discovered that the plastic tail wheel hub was broken and the wheel wobbled all around the axle. It caused some exciting and comical taxi attempts.
So, a new metal hub tail wheel and a shorter prop (16x8 or 16x6) are on my shopping list for the next trip to the hobby shop.

Winds are forecast to be gusting to 30 or 40 here today so, I'm grounded. That's not a bad thing as it gives me a chance to fix the issues with my SW.

Please keep us posted on your progress.

Garry

AA5BY

Yep... grounded here for wind as well. Thinking I'll run to the man's candy store (Harbor Freight) and see if they have some springs suitable for tail wheels.

ps....They did... now I've plenty of spares.

AA5BY

Well... that was interesting. If ones uses too weak of springs on the tail wheel... be ready for some course changes on takeoff run. I'll be happy not to experience that again.

The wx was absolutely beautiful all afternoon and I was anxious to fly after work. Got home about 4:30 and by 4:55 I was at the field. At 5:00 I was headed back to the house for the wing and canopy bolts. At 5:20 I was back at the field and had time for one flight and a short one at that.

After the hairy takeoff run... all went quite well. Needed a couple of clicks of down trim. With both elevators now following the pitch trim lever, I'd adjusted it approximately half the value of the up put in Saturday and it was close. The elevators are now trimmed up at high power about 3/16". It continued to have a linger aloft problem at that high power setting so hitting the gear switch turned on the low throttle mix that turned on the down trim at low throttle. That allowed the plane to establish a reasonably good landing glide slope... perhaps a whisper too steep... but not much.

Low power trim was 1/16 down from a neutral elevator so would probably by ideal with a neutral elevator. That means that there currently is 3/16" trailing edge of elevator variance between power on/off trim. More on this another time.

AA5BY

Changed to stiffer springs on the tail wheel.

Checked the CG inverted on the machine and it is now right on, which means that my suspicion was likely true that a slight wing incidence adjustment is needed and I've made the first by gluing a sliver of 1/64" plywood to the bottoms of the forward bolt holes and the top of the aft bolt holes. This first increment adjustment didn't require any filing on the opposite side of the holes.

The effect is to move the wings very slightly more positive, which will require less elevator up trim at full power and bring power on/off trim closer together. We'll see.

rowdyjoe

My Feedback: (9)

Glad you got to take advantage of the good weather today even if it was just an hour or so. 1 flight is better than no flights.
I worked on the SW yesterday and was was so stiff and tired when I got up this morning Iwrote the day off. Just sat around moaning, grunting, and groaning unitl about 4 PM (I had taken a pain pill about noon).
I went to the hardware store and bought a GFCI outlet and replaced an old one with it in the garage. That got me started so, Iput the Yak on the bench and commenced to work on it 'til 10:30 PM. Without a clock in the garage, I loose total track of time ...especially after dark.
More about the Yak on the appropriate thread.

RJ

AA5BY

Making some hay today while it rained... I built a stock feeder... or that is what it looks like. Actually, it is a ceiling mounted wing rack.

It fits the space available and will hold wings for five planes.

rowdyjoe

My Feedback: (9)

Wow ! Nice job and Great idea. I need something like that myself. I've GOTto start hanging planes from the ceiling as Iwant my HOtrain layout back.
I have 2 more birds to build, both nitro, and I have no place to put them when complete. I need to get started soon because contest season is right around the corner. My IMACbirds are almost ready but, my SPAbird (an old A6 Intruder by World Models) needs to be assembled and my Escapade .61 needs to be built.

RJ

AA5BY

Planes that have a wing tube are very simple to hang from the ceiling.

rowdyjoe

My Feedback: (9)

Excellent method. You're just full of great ideas.

RJ

cymaz

Brilliant ideas, thanks for the inspiration

rowdyjoe

My Feedback: (9)

I flew the Spacewalker again yesterday and she flew very well but, Imay remove a bit more weight from the tail to make her just a tad more nose heavy.
I experienced a very exciting takeoff, similar to yours but, mine was due to tail wheel departure. Ihad replaced the plastic hub tail wheel with a metal hub wheel but, evidently didn't get the axle secured very well. Initial takeoff roll was OKbut, it soon turned into a rodeo. It was all over the place. Ilifted off thinking Ihad really dumb thumbed the takeoff. It wasn't until I shot my first attempt at a touch and go that I discovered the tail wheel was gone. That unmistakeable and terrible sound of scraping metal met my ears and Icringed. I brought her to a full stop and sure enough the wheel had departed. So, we straightened her out on the runway and took off again. I flew a few more minutes, landed and put her away for the day. One flight successful flight was good enough. We'll see how well the new wheel works this afternoon.

The engine was hard to start cold but, ran well after she warmed up. These smaller engines seem to be that way. It's running a bit rich but, a tweak on the low end needle should help it. The new throttle and choke linkage worked like a charm so, I was relieved. She idles down just fine now and approaches are much more controllable.

I have a few control surface tweaks to make but, she's stable and safe now and Ifeel confident in her handling and the engine.

RJ

AA5BY

Good report RJ... a new bird always requires some tweaking and discovery of building errors. Getting it home safe during that time is always a relief.

I flew mine again today. To remind, I'd added shim to increase the wing incidence slightly in an attempt to bring the power on/off trims into alignment. When adding the shims, I did not do any filing on the other sides of the holes, which left the wing bolts very tight to install, doing so to verify before filing. An additional two clicks of up trim were removed today, which leaves it two clicks away from a neutral elevator that had previously been verified provided good power off trim.

So... when home the holes were filed on the opposite side of the shims just enough to remove the excess bolt tightness. Will fly again there to see if that is all that is required to remove the last two clicks of up trim and obtain a neutral elevator for powered flight and have power on/off trims aligned.

I've also got to check the elevators by taping some sticks to them to verify they stay aligned as sometimes it feels like some roll is being introduced with elevator.

Changing to stronger springs from the previous ones tried on the tailwheel solved the ground handling issues of the previous outing.

Arlyn

rowdyjoe

My Feedback: (9)

Two successful fights today but, that engine isn't any easier to start. Ihad to borrow an electric starter and choke it to get her going. Again, once warm she started right up. Grrrrrr ....aggrevating. I checked the plug and it appears she's running a bit rich so, Iwonder why it needs the choke to get her going? We tweaked the low end needle about 1/8 turn toward lean and it helped so, next time out I'll give her another tweak. She's still 4 stroking below half throttle but, she's still fairly new.

Iincreased aileron and elevator throw but, left the expo at 50%. She's a very gentle flyer and easy to get used to. Landings are a breeze when you get the speed right. She floats along very nicely and will hold ground effect as long as you have a bit of throttle. She settles very nicely when the power is all the way back.

Hands-off in the vertical, she falls toward the wheels so I'll add a washer to the lower engine mounts to see how much it improves the vertical line. I have a couple of clicks of up elevator and thought she might be a bit nose heavy but, the washers on the engine mount should fix that issue too. She seems to be fine in yaw and roll and I have her trimmed nicely. She will seemingly fly straight and level forever.

She's a very enjoyable and fun airplane to fly and once I get the engine issue worked out she'll be very sweet.

Sad to report that my Yak crashed on first flight today. See my post on that thread for details. (:

RJ

AA5BY

I had a minor mishap with the Spacewalker tpday. Our field is at the top of a long hillside perhaps a mile down hill to the Sabine river. We had a SW wind and sometimes wjen its gusty that induces wind shears on our runway. Three of us experienced them today and the Spacewalker with that large wing was on takeoff roll, had gained 2-3 feet of altitude and was slammed back down where the gear hit the runway and it bounced back into the air and otherwise climbed out for a good flight.

When landing, it was readily apparent that one gear strut had sprung out. That was it... no other ill effect. I'd flown twice so called it a day. At home, it was easy to remove the strut and insert in vice and return it to its proper bend, which was a far easier task than repairing a ripped out gear mount that might have been the result had the gear mounting not been beefed.

rowdyjoe

My Feedback: (9)

Whew! Glad you got her back in one piece Yep, it's much easier to bend that aluminum gear back in shape than the major job you could have been facing. Looks like the reinforcements you made were worth the effort.

We had some pretty freaky winds today too but, they were right down the runway out of the south ....thank goodness. I'd estimate the winds to be 10 to 15 on the ground but about 50 ft. up it was a different story. It bounced around some pretty heafty birds today. I was really surprised to see a 40% Ulitmate Bipe with a 150cc engine get bounced around like an electric in a 10 mph breeze. Fortunately, it was intermittent and didn't last too long. The winds began to lay down as it got closer to sunset. My last flight was really nice.

RJ

AA5BY

Elevators were found to be slightly out of alignment with a 1% offset correction needed. They were also non linear in travel and required setting slave at 95/90 mix travel to avoid over travel of the slave so that could have been why I was feeling some roll in loops or it could have simply been wind. This plane has a fair degree of dihedral and lots of wing so is subject to greater amounts of wind buffeting than I'm used to.

jloane

Hi guys.

AA5BY

Still getting mine trimmed out. It seems that this bird wants a lot of expo. I've travels for the sport settings at 50% expo (started with 40%) and considering moving to 60% for trial.

jloane

Found that I needed the aerobatic throws for regular flight..the low rate settings were like flying a trainer...yawn..after kicking up to high rate they were fine. There has to be an advantage to adding expo, but I am not familiar enough with it to try anything...mine flies fine the way it is....I'd like to learn about exponential though..