FlyStraight

I think I'll leave the meter in the plane during flight and then get an accurate inflight measurements. Right now, my main concern is wrapping the wires in the plane in something that would prevent them from being cut by the vibrating fuse. I have about one gallon thru the engine now and noticed that my ign. batt. wire insulation is cut thru to the bare wire. I got some plastic spiral wire from work and will probably use it for the wires.

Right now, I run non-synth. oil at 32:1 ratio. I have one gallon thru the engine and one more gallon of the 32:1 mix. What mix should I run after the two gallons are up? Do you guys think I should stay at 32:1 mix for the break-in duration (which could be 15 galons total) or should I switch to 40:1 after two gallons of 32:1? Or go with 50:1? I don't have access to synth. oil here unless I order thru web. Got 64oz of non-synth. oil that I like to use up. I'm really itching to get this plane in the air and everything is a go except for those wires that I find now I have to insulate better. Thanks.

Grelker

My Feedback: (58)

i use 100:1 amsoil after 2 gals of breakin mix

FlyStraight

Grelker,

once I'll locate amsoil, I'll try the same ratio as you. For now, I think I'll continue to run 32:1 mix on the non-synth oil I have.

I've noticed that at any point the wires touch the wood, the wire insulation is getting frayed so I redid all my wiring. Most of it is covered in that orange spiral plastic sleeve. Works very well. I took down the elevators and redid the insulation there as well. I then epoxied all the control horn screws and tailwheel screws into the wood. I omitted this step early on thinking the screws would hold but I like to be safe than sorry. I intend to keep this plane for a long while so I'm taking extra steps to make sure everything is working as the way it should be. I've got sick over the week so the maiden will have to wait until next week. Here in arizona, we have thunderstorms in august so hopefully I'll get a window of opportunity for flight between them. If anyone has any better ideas about insulating wires, etc. please let me know. Thanks.

FlyStraight

Maiden:

It was overcast and a 20mph wind gusts, not a bad weather for maiden. As long as the sun is behind clouds this time in AZ, all is good. Balanced the plane long. and laterally per manual ie. 4 1/4" behind the wing's tip L.E. . Ran about gallon of fuel on the ground and 2.4ghz Frsky with 8ch rx. ranged checked to 30 paces. Taxing no problem, but I richened high speed needle on engine just in case. Took off nicely from our paved runway and into the wind and the first thing I noticed was how sensitive the elevator was. The plane was all over the sky, ailerons were also a bit sensitive. Was running 30% expo on flying surfaces that were set to low rate ie. 20-30deg. as per manual. Then I noticed that the engine is running excessively rich. I did two loops around the sky fighting the sensitive elevator. At the far end of the runway, over the soccer field, I stalled the plane as I was turning onto final about 75 feet up in the air. The plane pancaked tail end onto the soccer field, bounced into the air another ten feet and then settled onto the grass. Final analysis showed no damage except a small hole made in the rudder from the tailwheel as it slammed into the ground first. I kept the wings level so they were not damaged.

First thing I must say that the plane is build like a tank. For sure I thought I lost it. Second, I think the plane is tail heavy by how sensitive the elevator was. I only flew for about a minute so I didn't have time to trim it out or get more flying time with it. I'm going to add more weight, about 4oz or more to the nose, then I'm going to dial in less throw for ailerons and elevators mechanically. I already leaned the top end on the engine.

When I stalled the plane, it was in a shallow dive on base leg and I just tried to turn it little more, then the plane lost more speed and all of a sudded I found myself in a deep stall. Like the elevator acted as a huge airbrake. I had 20deg max up throw on it. Manual said on low rate 12deg and high rate 18deg but I was thinking 20deg and use expos. I only use single rate with expos on my other planes. I like to set my plane on high rates then use expo to soften the travel.

Question:

Should I leave the elevator max rate to 20deg or should I lessen it and to what? How much up in deg. do you guys fly at normal IMAC stuff? I'm still going to add weight to the nose and hope I have enough elevator authority to pull the nose up during normal flight. On my other planes, I fly slowly with wings level and just above stall speed then I feed in up elevator until plane stalls, then I have no more up travel avail. and that's how I set my up travel. All my other planes started nose heavy except this one. Thanks.

P.S. the picture shows the only damage to the rudder from the hard landing.

FlyStraight

I'm going to keep the same elev. settings and just add a pound or so of weight to the nose. Not going to bother moving stuff forward for now. Later I'll see if I can move some stuff around so I don't have to use all that weight up front. With that pound of weight the plane will weight at 19 1/2lb. I wonder how much one can save on weight if going with CF tail gear/stab tubes setup. If I could save 2oz I would think about it.

Grelker

My Feedback: (58)

FS - I would encourage you to go with the factory settings for low, high and 3D rates and increase your expo before you start adding weight. If you add more weight, the plane will stall at higher speeds than it does now. Remember to keep your speed up and don't get too slow until your final leg. If you do add weight, move the cg forward 1/4" or so at a time, then fly it. I set my cg's to the factory spec and then add 1/4 to 1/2 oz of stick on weights to the nose or tail, then fly, and repeat until it feels right for you. It helps to put a piece of masking tape on the plane to use to stick the weights onto, saves the finish.

I use 60% expo on low, 70% on high and 90% on 3D. Your elevator setting is a little more than the recommended high rate, so try 70%-75% expo. I don't fly IMAC but i'm sure they will tell you the low rate or less is what they use for flying sequences. The control setup is different as well, they would have the max servo throw yield the low rate deflections or something like that.

Let us know what you decide.

FlyStraight

Grelker,

thank you for your help. I've decided to balance the plane on the middle of the wing tube. That required adding 14oz of weight to the nose to move the CG forward about half an inch. Then I lowered my low elevator rates to 15deg each way, high are at 23deg. I'm running 35% expo on low rates and 60% on high. I might add more on the field. I also tamed the rudder and will probably tame the ailerons. I'll try to keep the speed up when flying. With the lower rates, forward CG and good engine I don't see problem flying this plane tomorrow. Now that I know how strong it is, I feel little bit relieved in knowing that it will hold up. Wish me luck!

Grelker

My Feedback: (58)

Let us know how it goes.

skysfallin

My Feedback: (10)

Flystraight, If you are at 18.5lb now you would do well to add carbon gear and carbon wing tube. This will take out almost a lb of weight. My Yak weighed in at 19.5 and That is what I did to take it down to where yours weighs now. Your plane will definately fly better with less weight. I found the manual CG to be perfect. I think it is 4.25 or 4.5 at the wing tip. That puts me almost neutral when inverted. Try to move your batteries to get your CG correct. It is non productive to add weight to any airplane. You definately don't have to do it with this one.

FlyStraight

Just got back from the field and the remaiden was a success. I would say after doing the adjustments the plane flies 100% better. At the field I toned down the aileron throw from 100 to 70% and added more expo. One roll in about one second. The elevator throw is about perfect. The plane is little nose heavy, added about 3 clicks of up trim, flies inverted with just a touch of down elevator. Rudder has about 25deg throw and it holds the knifeedge.

So at least I got the plane in the ballpark and will adjust throws and CG as I fly more. The other issue is the engine. When I flew, it was about 105F in the sun at 9am. The engine ran good on the ground but the low end richened out in flight and so I have to continue to lean it out as the engine is being broken in. It's tricky because I don't want to lean it out too much to get a good transition but then run the engine hot in this hot weather.

So I balanced on the middle of the wing tube and that is slightly nose heavy. Before it was balanced at the very rear of the wing tube per manual and that was very tail heavy. So I guess the right setting is somewhere between the middle and the rear. I will keep removing the weights in the nose to get good CG. I have a spice plastic bottle filled with 1oz fishing weights so it's easy to remove weight from the plane in small increments.

Anyways, I probably wrote too much already as I don't usually write much about flying but wanted to document this for others new to this plane and to giant scale planes. I will consider the carbon fiber parts that some of you mentioned. I too like my planes to fly light as they're more nimble. As of now, the plane flies very smooth but is not as nimble as my electric stick and not as easy spur of the moment to land. Maybe as I get it lighter, get more flying experience and increase the throws, etc. the Yak will fly better. I will write here of my experiences as I gain more flight time. Thanks all for your help.

Some pictures of the arizona desert. I overfly the green soccer fields when I land and that's the only green place around as they keep watering it all the time. Can't fly when there are people there but the place is usually empty. Also have to dodge four tall and huge stadium lights when landing.

FlyStraight

Something else I wanted to say. Recently I bought the 2.4ghz radio module and receivers from Frsky. Got the 4ch. single antenna and two 8ch. dual antenna receivers. Module and 8ch. receiver costs something like $55 with $11 to ship from china's Himodel.com website. My total was like $120. Installed the 4ch. into my radian 2m glider and one 8ch. into my .40 size GP big stick converted to electric and also into this Yak gasser plane. I have no problems flying with frsky. It hops on like 20 channels and has dual antenna redundancy, if one loses signal it switches to the other one. Went with 2.4ghz over 72mhz as on our field we have lots of newcomers and didn't want to take the risk of being shot down, plus the pain of radio freq. flags, etc. Also, now frsky has the high voltage and telemetry receivers so no regulators needed if using lithium batts. I use nimh so I got the low voltage ones. I think rx can drop down to 3 volts before it resets, and reset is instantenous. It also has failsafe, you just hold sticks where you want them then hit a button on the rx. On the back of module it has button for binding that also acts like range check, puts module into low range ie. 30 paces. I'm very happy with the system and just wanted to share it with you in case you have older module based radio and need to switch to 2.4ghz cheaply. The entire plane minus the futaba 8U transmitter cost me US $2000. Everything is new and I saved about $200 using the $60 tower hobbies discounts on stuff ordered worth more than $300. Got the DLE 55cc for like $350. No discount on the plane which was $700 drop shipped from AW. Ok then

FlyStraight

Update:

so after 100 flights and two crashes, these are my observations. The plane is holding up great. The only problem is the excessive wear on the canopy's front edge that goes under the engine's cowl. I tried to put spacers under the engine cowl's two top bolts to relieve some pressure but it was worse, so no spacers.

On the issue of CG. The CG per manual is right behind the wing tube and that will result in a nose heavy plane, perfectly flyable. I had it balanced there plus on my remaiden I added 14oz of weight in the nose. The CG then came up to the middle of wing tube. The plane was nose heavy, flew imac moves very straight, nose was difficult to veer off course. Landings were done on the mains and I experienced loss of tail authority after touchdown. It was impossible to taxi the plane in light winds, tail was not stuck to the ground as well because of the nose heavyness. The wings rocked hard in slow flight and on landing it would stall with wings with low angle of attack.

I started moving the CG back, one ounce at a time. When I went from 14oz to 8oz, I noticed very little wing rock at near stall speeds, landings were three pointer and the plane stalled without wings dropping off that much. I removed all the weight, the CG is now 1 1/4" behind the wing tube, using 7 degrees of elevator throw for a 20 foot diameter loop at cruising speeds. Takeoffs and landings are very slow, at jogging pace, stalls are straight ahead and rather mushy and no wing drop on landings. Can taxi in 20mph gusts and takeoffs under two feet and can hover land the plane in 10mph wind.

I feel that the CG can further go back another half inch. I'm going to keep it here as I fly imac and I eliminated wing drops and wing rocks. The rudder is more sensitive especially on the pulling maneuvers but doable.

The plane is a lot of fun to fly. The main gear is wearing out so I bought some sullivan skylite wheels. I bought new sullivan 24oz tank that is a perfect replacement for the stock one, I use t-fitting now and it works great. The plane is bone stock nothing carbon and flies great. I fly knife edge loops with snaps at the bottom, lomcevaks, knife edge spins, unlimited verticals, basically I push the airframe and it withstands all the punishment so far.

I feel that the airframe is going to last at least me thousand flights if not more. Forgot to say, some of the dowels are coming lose and I just CA'ed them in again. I don't use the cotter pins for anti-rotation pins since they're hard to put in and I was damaging fuse sides. I put zip ties on them so I can pull them off.

So although my building impression of this plane was not super great I feel that the flying quantities and the structure robustness made up for it. Also, the landing gear area with the lighting holes cut is sufficient strength for normal landings including harrier landings providing the CG is setup according to the manual or even more aft. With nose heavy doing a crosswind landing the main gear can rip the fuse side out, that's how I found out.

This plane became my favorite to fly, very smooth, consistent speed, and strong. Would definitely buy another one if I crashed this one. I forgot about all the other planes when flying this one.

macboss

My Feedback: (44)

FlyStraight,

I finished an AW 500 Yak about 2 months ago. Weather in OK has been windy and I held off on the maiden until the wind was down. I'm using a 3W55 with a canister. It flew great. I forgot to weigh the plane but the CG is about on the factory recommended location. I added no weight to balance but the 3W with canister adds more front weight. To get balance, I have my two receiver batteries (LI ION 6.6 volts) in the radio compartment. I found the elevator to be sensitive and have it on low rate with high expo.

Plane flies great and lands easily. I keep the landing speed up and do a wheel landing. Of course, the wind is back up and we are getting rain. I had a WildHare 50cc 540 Edge: had a deadstick (out of gas) when on final landing approach, hanging on the prop about 10 foot up...belly flop. A local member of our club was selling the unstarted Yak for low dollars and I decided to buy it rather than try to rebuild the Edge. I'm glad I did.
The cowl had a few stress cracks so I installed a plywood cowl ring. This really strengthened it and I think it fits better over the canopy cover. I also installed an engine baffle to ensure the 3W gets lots of air right over the fins. I also bought the carbon gear. This really helps smooth out landings if I get a little hard on the touchdown.

You have a great thread and I hope others read it to get your suggestions: particularly the one about protecting the various leads from abrasion on the formers, etc.

FlyStraight

macboss,

thank you for kind words. This yak has outlived all my aerobatic planes so far. The optimal CG I think is one inch behind the wing tube and the plane does the most beautiful and slow three point landings I've ever seen with no bounce at all. I changed the stiff sullivan skylite wheels for some soft rubber dubro wheels because during high speed takeoffs the sullivan wheels bounced making my plane veer off course. I'm no longer doing any harrier landings with this plane as I broke every bullkhead in the landing gear area and wood is now breaking beyond my repairs. For gusty wind harrier landings I just ordered eflite eratix and will beef up the gear on that plane. My 59" AJ slick sadly did not survived my last grass emergency landing and the gear ripped out and it looked like confetti inside the plane. I did not liked the carbon gear in that plane because it transfered all the shocks into the fuse and into the weak cheap lite ply bullkheads completely delaminating them. It broke my heart as the plane was super strong in the air and after flying it I did some of the same things on the yak discovering that it can do them.

If one omits doing harrier landings in gusty winds then this yak as it comes stock is perfect. It is a little heavier than other planes but it is also stronger and that to me is a good tradeoff. I can still high alpha knife edge this like I did my slick plane. Obviously not at that slow a speed but slow enough for me. My knife edge loops are much tighter now about the same as the slick's. Not only does this plane flys as well as the slick but it is also more stable in the air because of the weight and momentum. It is a superb IMAC/pattern plane on low rates. Today I did 20 minutes of nothing but rolling maneuvers, lots of horizontal rolling circles, few in vertical plane, etc. I felt very comfortable flying them in any orientation and about half throttle. One doesn't get this much flying time other than on a simulator. With my slick, I would have gone thru three 4s 4000mah batts in that time.

Also, my local ACE hardware store carries the same tail wheel springs except that the ends don't protrude from the coil that far out. So for that I bought some fishing swivels to use as anchor hooks on both ends. My tail wheel springs broke at the bends. I'm using 1" sullivan rubber tailwheel with the alum. hub drilled out for the tailwheel wire size. I fly off rough pavement and the sullivan wheel is lasting a long time. My tailwheel has little slack in it and that helps to absorb any shocks. The EZ mini connectors are holding up great. No problem with the tailwheel setup after my improvements.

The canopy and cowl hex screws are wearing out so I bought some stainless steel dubro 4-40 x 5/8" socket head cap screws and they'll work perfect and be much more resilient. They're expensive but worth it. I kept changing the canopy screws for the cowl screws as I don't remove the cowl that often until I ran out of good screws The canopy and cowl screws are interchangable.

The longer I have the plane the more I notice what needs to be changed or made better and so far I'm noticing that with the few changes I had to make the plane is holding up great and maybe no further improvements need to be made. One of these days I'll make a list of things that I've done to improve the plane so others can do it from the start.

FlyStraight

macboss,

after 117 flights, my cowl has no stress cracks so far. I did round cuts on the cowl openings with my dremel's mini sanding wheel. Then I added thin CA all around the cuts and it wicked into the fiberglass. I did that for cowl screw holes as well. The holes did elongate little bit now because of the vibrations but it's ok.

I'm not using any engine baffle and I have no problems with the engine cooling so far. Flying in 95F weather now. It probably runs at higher temps than your baffled engine but no problems so I'm going to leave it unbaffled for now.

But your suggestions will definitely help others with the same engine, etc. So thank you for making them.

Are you using the AW suggested carbon gear for your yak? If it can spread out on impact and absorb the shocks without cracking then I might get it to save some weight. My friend's gold wing 50cc sbach had a little harder landing today and that gear is pretty stiff so it transfered all that impact to the landing gear braces and broke them. I don't like how they're using that cheap lite ply there. Over here in AZ, it dries out and then delaminates on impact. Totally sucks.

macboss

My Feedback: (44)

Flystraight- I did buy the carbon fiber gear. I think is is good quality. It is a bit thicker than the aluminum gear so I had to cut the groove in the gear cover block deeper to allow it to fit. It also stands a little taller than the aluminum gear. The gear mounting blocks look strong but I'll watch them for fatigue.

Flew a few times last night. Really like the way it handles.

I'm getting ready to maiden my AW 110" Cub Crafters S-2 Cub. Hopefully Tuesday evening.

rktman56

Flystraight - What is the dry weight of your Yak? After 117 flights, what prop did you find works best?

FlyStraight

The dry weight is 18lb 5oz. Everything is stock hardware and I don't use wheel pants. I use xoar 22x8 laminated wood prop and haven't tried any other prop yet. I might try xoar 23x8 for more 3D flying when I use up my current props. I just put in rudder to elevator and rudder to aileron mix at very low percentages and it helps a bit. My yak has a tendancy to couple to the gear in high alpha knife edge. Just started doing harrier rolls and so far so good. I need to fly more to practice slow high alpha flight to figure out where this plane stands in slow 3D department. I might end up moving the CG forward about half an inch because it's a bit unstable in high alpha rollers and snaps. But I do like the aft CG for a very nice three point landings. I love how the big nose slows down the plane in a steep landing approach. It totally sounds and looks like a real airplane landing.

FlyStraight

I took out the sullivan skylite 3" wheels because they were too hard and made the plane bounce all over and replaced them with $6 dubro low bounce 3" tires which I think are the best tires for this plane. They seem to be durable and will not bounce your plane even during ground loops. They provide very good shock absorbtion and I believe if I had them on earlier, my landing gear damages would be smaller. I did have to drill out the plastic hub slightly but no problems. Also eventhough they are soft tires, there is no problem doing high speed takeoffs and they don't have any tracking problems on the runway or during a crosswind landings, etc. No problems whatsoever. Here's a link:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXD793

FlyStraight

I rechecked my CG and I must have made a measuring mistake because my CG right now is only 1/4" behind the wing tube. I went flying and trying to do some hovering and I just kept adding lead to the tail gear. In the end I ended up adding 2 1/4 oz to the tail. I might still add maybe a half an ounce. That put the CG 1/4" back of wing tube. I took my 12oz rx battery and moved it from the front of the fuel tank and right atop the wing tube. I might move it on the tray behind the wing tube. The CG now shows a hair behind 1/4" back of wing tube. I also redone my elevator throws for a total of 40 degrees both ways. I'm hoping that will be enough to correct the hovers quickly. I had 32 deg. of elev. throw and on full throw I was getting major wing rock. So maybe with 40 deg the air will separate from wing for no wing rock. I also noticed the plane at 32 deg throw was very unstable as far as pulling elevator went. It would yaw every which way with full elevator throw. On top of that I had wing rock.

I'm at 142 flights now and my main goal is to make this a 3D plane as well as precision plane. I have 10 deg of elevator throw on low rate and it will not wing rock at full low rate elevator throw and I can fly precise maneuvers with the CG of 1/4" behind wing tube. I do my 3D stuff then switch to low rate for landing. It's too unstable right now to land on high rate and I'm using 70% expo and just changed it to 80% so tomorrow I'll see how these changes work out.

FlyStraight

Went flying today and noticed one of my wheels got cut by the wheel hub so the soft dubro wheels don't last long on these heavy birds. Friend gave me some normal dubro 3" tires and their side walls seem beefier or stronger so hopefully they will last much longer. However they probably are not as shock absorbing as the super soft wheels. There is no problem with mounting the battery on top of the wing tube so far. It doesn't move laterally nor back and forth from the vibrations. I might just leave it there and bring my ignition battery from top of the motor box to the front of the fuel tank where my old rx battery was strapped in in case I want to move the CG back more.

I added 100% expo on high rates of 40 degrees on elevator and it seems to be more stable and I think I can now land on high rates. My hovers are better now but I did noticed with the aft CG now the high alpha slow knife edges couple to the gear a lot more. I'll put the rudder to elevator mix back in and see if that cures it. Also, my knife edge loops are tighter which I like. The landings are slower as well and the plane almost comes to a stop upon landing in slight winds. The plane feels light on the wing now. I still have lot of wing rock. I might move the CG back some more but don't want to yet before I get used to flying my knife edges. This is my first giant scale aerobatic plane and I'm still learning about the possibilities of this type of plane and don't want to rush the learning process. I'll keep experimenting and commenting here.

FlyStraight

Found a video of me flying my yak a month ago. One of my friends video taped me.

http://www.youtube.com/watch?v=ngc3qKphmNQ

captinjohn

Nice video with a nice landing ....about 11- 12 min later. Do you know if this 50cc Yak is set-up for a tunned muffler like on a Dessert Aircraft 50cc engine. If it does not have a tunnel....would it be hard to build one into it? Like a big modification. Thanks Capt,n

Mark Dennis

My Feedback: (4)

John,
The 50cc Yak has a full length pipe tunnel that can except just about any tuned pipe or canister system. Here is a picture from our website that shows a KS 1060 Tuned pipe installed.

Please let me know if you need anything else.

Mark