Eflite Cubby Wing Update

I did some more work on the Eflite Cubby wing today. I ordered the Cub Yellow cote from Horizon Hobby through Amazon, and it doesn't come Prime (2 day), but will take about a week. The whole point was to order it from Amazon for the Prime shipping instead of direct form Horizon as I usually do. Meh.

I sanded down the epoxy, and afterwards filled the slight imperfections with Hobby-Lite. Smooth as a baby's bottom. Sweetly straight.

I decided to drill out the old spar. It was about 1.5 cm on each side. This is the wing side.

This is the center piece side.

Melted a hole in my brand new Batman Hoodie with a hot drill bit. Awesome...

The new wing spar. Ridiculously small. Cut it from plywood and sanded to fit.

15 min epoxy, filled the slots where the spar goes and the joining sides. 

Came together nicely.

Nice and straight!

The plastic connectors that were originally on the damaged right wing snapped in the crash. I moved the remaining ones around so that there are 4 of the original white ones on both wing strut ends, and used control arm snap links from my HDX 500 heli repair kit to replace the damaged ones where the struts attache to the fuse. Perfect.

Waiting for the cote to come in, which will let the epoxy set well. Once the cote is in, install the wing and back to flying condition!

Bushed the Cub, Rocked the Sukhoi

The weather was perfect, really, so I was going to fly today. I loaded up the Sukhoi 10cc, which I haven't even started since last fall, and the Eflite Cub, then headed out to Joppa Fields, just in case they fixed it. Which of course they haven't. The grass has been cut, but its still tall to mask the clumpiness. I've really just had my fill of that. I got back in the car and drove out to Merrimack and the field for the Southern NH Flying Eagles.

Its a nice field with a geotex runway and very nice recently mowed grass, but I don't enjoy flying there, with having to fly in and out of the hole formed by the surrounding trees, which you pretty much have to fly over at least 100 feet in the air to avoid, and the wierd wind patterns that come off the river and spin into and out of the bowl and around the trees. I think I have not flown at a club with more crashes, which I attribute to the trees, the bowl and the winds.

And pretty much everytime I go there something crashes due to the heights, the winds or the trees. Today the Eflite Cub got wisked sideways then into a spin, in the corner over the creek at the northern end, after flying with busy fingers down into the bowl. She ended up in a bush just short of the creek. Motor is loose, right wing came off clean and has a break in the outer leading edge. Meh, easy fixes, already in progress.

The Cubby is a very nice 450 sized balsa framed plane. A nice predictable flier.

In the bush...

Right wing took the brunt, but came off clean. Well designed to break like this instead of being so strong the energy turns it into matches.

The leading edge. I used 15 min epoxy to allow me to work the pieces into place.

I placed a piece of balsa sheet cut to fit perfectly between the wing formers, and to fit behind the rejoined leading edge. I need to get some Cub Yellow cote. Thought I had some, but nope.

This is the trickier part. Do I want to drill out the joiner spar, which would be strong and easy to do, but will take some work, or drill a hole and run a carbon fiber rod between the two. This latter option  requires a little more finesse ensuring the rod is in the same place on both sides joined. This option is weaker. Meh, I think I will take the time to drill it out and make a new plywood spar joiner. That is a project for another day.

I love this plane. My RCGF 10cc powered SU-26, is a lot of fun to fly, especially with the Orange stabilization system. The system is switchable allowing nice clean aerobatics with it off, and with it on, nice handling in windy conditions. She started right up and needed NO adjustments! Ran sweet and reliably.

On the geotex runway after a flight. Flew a couple of tanks, 15 min each.

Then the plastic control rod end that was embeded in the rudder broke off. I could fly her castering, but with the cross winds this was a bit tricky so I called it a day. This took about 10 min to fix at home, and I decided to double up as these take a beating on grass. Fixed. I also took some time to straighten and align the aluminum landing gear that also took a beating out at Joppa Hill last fall, another reason not to fly there. Recall I have had a lot of landing gear ripped off there.

Sean showed up. Twice. Forgot his wing tube the first time. Flew his glow 0.55 equipped Phoenix Cub. Ran sweet, took off fine, and then I left him to the winds.

It was a good day. Not sure I will fly there again, but its a great club, some really great folks. I just have better options than flying in and out and over the hole.

Ignition or Hall Sensor?

Thanks to the gang at RCGF-USA, the new ignition arrived today, wicked fast shipping.  I installed it today, and at first, nada. Dammit. I tried a different Hall sensor and it flashed, curiously without the spark in (forgot to put it back in!). Didn't want the new ignition to short, and replaced the spark and it still worked. Realized there apparently are two different sides to the Hall sensor... tried the original one curved side down and it sparked. Hmm... I am not even sure the original CDI is bad, so I am keeping it. Anywho, the engine started up and ran fine. I retarded the sensor a bit and she runs even smoother. I haven't played much with the timing, so this was nice. Throttle advanced smoother too. Sweet. Ran her a bit, but too windy to fly. I did have to remove the 4 blade prop. It just didn't have the ruggedness required for the gas engine and was splipping on the prop shaft. She flies great with the Master Airscrew Scimitar.

I am loathe to return to flying at Joppa Hill with the clumpiness of the grass and how hard it is on my planes. I have lost so many landing gear there, and will never fly the Waco with her wheel pants there again. Pretty soon the road to Misfits in Auburn will dry out and I will fly pretty much exclusively there and on occasion at Hudson.

Looking for some flight time on Thursday!

I fly, I cry...

So... I reset the accident clock. But its not so bad. Sure, a foamie bit the dust, but, I don't like foamies so no tears shed. Though I sort of liked this one... More on that in a moment.

I got out on a beautiful though gusty day, flying today out of Southern New Hampshire Radio Control Club, on the top of the Trash Mountain in Hudson. Its always windy up here. Today was no exception.  I met Ed van der Veen as he was finishing up seeding the field. Nice to meet him!

Pretty windy day, but more than not, straight down the runway.

Brought out the Stik. Ran great, until she didn't.

Brought out the Hobby King foamie Sbach. Flew lousy, right to the scene of the crash. I knew it was too windy for her, but really didn't care. I don't know why, but I knew there was a risk and decided to give it a shot. I had no doubt the Stik cluld handle it, and she did,  but the foamie I wasn't so sure.

All set!

Beautiful up here on the top of the hill!

The top is curved, so, the runway is too.

Looking over the field to the dump that we have to drive through to get to the top of the hill. 

You can see how steep the access road is.

She flew fine in the wind, with the stabilization system taking out the wind buffeting.

Before her last flight of three, she stopped in idle twice when I moved her from the table to the runway. 

So it was no surprise when about 5 minutes into the flight the engine quit on a downwind, and I had to dead stick her into that heavy wind. She came down fast and I lost sight of her as she dipped below the curve of the dome, and I had to land her sight unseen. She landed without a scratch.

Looking good!

But when I went to restart her, she wouldn't, and on the third try this happened. I have no idea where the prop nut went. I am sure the engine turned over a couple of times, but then the prop came off. I can't find the prop nut anywhere. I think the "pops" I heard was backfire, but this suggests the spark was working? See below.

So I flew the foamie Sbach. I had flown her fine last fall, and she flew perfectly. I rather enjoyed it I always do a control check before every flight, and everything was curiously backward. Every one of the inputs. I reversed them and they were fine on inspection. I took off, she was a bit erratic, attributed it to the wind, clicked on the stabilizer and all hell broke loose. Turned if off, and it was still all I could do to land her as her inputs were erratic, over reactive despite low D/R. I brought her to the bench and the inputs were fine, so I checked the stabilizer settings and the ailerons and elevator were backwards, but the rudder was fine.  Was this because I changed the direction of the controls? If so, why didn't the rudder change? I set them correctly, and then again, had to change the control inputs! But this time, the stabilizer system responded correctly. Took off fine, but started to get erratic, turned on the stabilizer, and it didn't change anything, turned it off, and tried to land. She got blown over to the runway behind me, so I tried to land her quickly, but she dived then porpoised up and belly flopped hard, tearing off the gear, which essentially ripped the bottom and front of the plane off. I am amused that I really don't care that she is busted up. I suspect it was too windy for her. Not sure what the control reversals were all about...

I put the 4 blade prop on the Stik because I could, took her out to the garage to see if she would run. No joy, no start. Took her back to the bench, pulled the plug, no spark.  Its never the spark plug, but I tried another spark plug and no spark; put the original back. While its never the Hall sensor, it was the cheapest thing to replace next if it was, so I swapped it out, and still no spark. It has to be the ignition that failed. The $70 ignition. This RCGF one isn't old, and it isn't cheap. It must have failed in flight leading to the dead Stik landing (see what I did there?).

I wonder if the plug connector is the same size on all of these ignitions, or do I have to by the 10cc RCGF one? 

Dropped the ignition. Can't believe its the ignition... I ordered a new one. Of course HobbyKing has them for $42, but they are out of stock, and the only other place I could find one is RCGF-USA for $70. I should have put a date on it, not sure how old it is, but when the new one comes I will. I really hope this is the problem.

Tune Up Day for the Stik's RCGF 10cc

Last time I flew the Stik she had some challenges getting and staying tuned. The QuikFire Filter is nice, but I am not sure they offer an advantage. I like the filter system on it much better than a screen, but honestly I don't know its any better than a simple screen filter. Certainly its costlier. I don't know that I will include them in my next build. This one leaked, so I replaced it with a simple 3-way screen filter. The engine runs so much better.

I simplified the fuel system.  Kept the QuikFire clamp and used it to hold the 

screen 3-way filter in place. This cleaner approach to the engine from the fuel tank

made for a much smoother running engine, in particular with shifting

fuel demands in aggressive throttle management.

The RCGF 10cc engine continues to be a bit of an enigma. I still love them, and don't think there is a better, more affordable 10cc engine. But I have to admit I have no idea which way to turn the low needle... Conventionally you tune the high end for max RPM, and that needle is easy. Then you tune the low end for smooth fast full throttle. One would think that if it bogs down, you richen it, turn it out. The idea being that it needs more flow. You find the leanest point that gives you a smooth, non-bogging transition. Tuning the low needle is a constant challenge on this engine. The other traditional bit is that once you get a gas engine tuned, that's pretty much it for the season. One of the reasons I like my Stik is the open engine bay: no cowl to take on and off, because it seems I am constantly having to re-tune the low needle.  I haven't flow the 26cc much, as I finished the Waco last fall just as the winter closed the flying season, but in the short time it seemed much more stable. The fact is, though, that I am breaking in a new cylinder on the Stik's 10cc, so it is expected to be a bit wonky.

Running the 10cc idle to full, half to full, back to idle, after the tuning. Max RPM and smoothest I could get the transitions. Too lean on the low needle and she would quit sometimes in idle, especially dropping from full throttle. Kept having to shift the low endpoint on the transmitter to find a good balance that gave me a reasonably low idle without stalling the motor on full throttle and on idle back. She seems to be running pretty smooth. I will be in Londonderry tomorrow for an appointment, so will pack up a couple planes to fly off the mountain top in Hudson at SNHRCC. We'll see how she does.

Looks like the gang at Misfits in Auburn have accepted my membership! The field is closed due to mud on the road in and the parking area. Once it dries I will be doing more flying out there. But for the need to have a buddy, the geotex is awesome, and the open space makes for better flying. I love the gang and the geotex out at Flying Eagles in Merrimack, but just hate flying in and out of "The Hole" of the trees that surround the field.

I am charging the packs on the Stik and the Sukhoi 10cc's, and some 3S 2200's for the HobbyKing foam Sbach to fly tomorrow. The winds at The Mountain are always a bit more brisk than the prevailing winds, so it may be a bust when I get there, but we'll see.

Finally got some flying in....

Finally. A beautiful day off with sun, little windy. The stablizing system came in handy.

Joppa Hill Fields in Bedford suck. The grass is so clumpy that my Stik with 4 inch wheels bounced madly and frequently got stuck, stopping the engine with prop strikes. Takeoff took almost 50 yards! The gound is mushy, saturated to boot.

I spent an hour trying to get the engine running again, now that its warm out... The low needle setting just would not find a sweet spot. The needles are out over 3 turns, anything less and she would not run. Ffinally found a good high, and an acceptable low. She didn't stall at idle or full throttle. She is running a lot rich, I suspect due to the new cylinder breaking in. If I lean it out I lose a lot of rpm. Tuning it I ran two tanks, almost 25-30 minutes of run on a tank! She has little vertical, but flies aerobatically fine and sharp. Put her through some paces and she stayed on line, held her speed, and turned crisply. She is predictable and fun to fly.

I need to remove the QuikFire fuel filter. Its leaking. Maybe I can fix it. The plane is flying a bit tail heavy, so I can't loose weight, but the fulter is sooo light so probably won't matter.

My fingers and head were in the game, no problems not having flown much of late. She idles high so comes in hot, but easily manageable.

It was a good day! Felt great to fly. But the field SUCKED!

I just bought a house out in Chester, so will be joining the group that flies off geotex, the NH Flying Misfits in Auburn, off Lake Massabesic. That wil end this nightmare filed condition issue.  Its a nice open field. Can't fly solo there as its next to a full scale grass runway, but that's easily managed. Looking forward to it!

Skiis, Hardpoint and Stabilization Success

Got out and up yesterday. Cold 30 deg in the sun, calm with mild variable gusts. It was time to test the skiis, the newly revised wing hardpoint and the stabilization system on the 10cc BigbStik.

A light snow in the morning, but most of the deeper snow has melted off. At this side it's shallow with grass poking through, on the far side about 6". I walked across to fly from the other side as is my new preferred side. It's that hard to walk on iced over snow

The new hardpoint addition. I redid the post on the wing, and added this extra piece to secure the anterior edge of the wing. That wing post hard point takes a lot of forces and I didn't want to depend on it alone. Worked perfectly, even in wind and aerobatics.

Wing attached. You can see how the wings snugs up under that new piece.

Today's tarmac. Using the wing bag to kneel on, trying not to make footholds in front of the plane so it can slide out for takeoff.

One of the issues with the skiis is that they offer virtually no resistance to thrust, so even at idle the plane wants to scoot off at high speed. This also makes roll out after landing a bare knuckler. This was a problem today. I gave it some thought when I got home and decided to use some of the L-rod I have for making vortex fences and CA'd some Vs to create a little resistance.

Tail ski. The hollow hardpoint twists against the Shea of being used as a tail wheel, so I filled it with epoxy.

Mains. Trying one set each side.

In flying with the skiis for the first time she flew a bit tail heavy, and there is a bit more drag. I pulled the few oz of weights off the tail and will recheck CG. I didn't do a CG check before this flight, which I realize was a mistake I got away with. Clearly the tail ski is heavier than the tail wheel.

Also on my last flight I toggled the stabilization system with the mechanics gloves I fly with in the cold. I use the F-mode switch on my DX8-orig, right above the ignition kill switch, left side. My finger usually rests between the switches, but with the gloves I have to keep my finger below the kill switch. To toggle the stabilization system I simply slide my finger up (on) or lift it over the switch and pull it down (off). Yup. Killed the ignition mid turn in a tail wind 10 feet AGL. Landed fine but in the middle of footprints in the snow without any slowing (skiis remember) so she was still shooting across the ground and she eventually tipped. That snapped the ceramic top off the spark plug which hangs under the cylinder which hangs under the nose, which was probably quite brittle and cold, despite the engine heat.

I had tried not using a gasket on the muffler header. It sprayed post combustion oil all over the place aft of and around the header. Got some gasket material today and will cut a gasket for it today. Back when I replaced the cylinder I noticed that there isn't a gasket between the cylinder and the engine block... I wonder if that is where some or all of this oil is coming from?

Replaced the spark, made the "ski draggers", new gasket. Waaaaay too cold today with heavy snow, but maybe tomorrow we fly.