Great Planes 25% Yak 81" 12-lb, seen on Fly3D Magazine
#751
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Got a reply from Graphtech saying they will replace the gear with one that has the same specs as the original... they responded right away!.
#752
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Hi,
Would a MOKI 210 mount sideways ( like OS160 ) without having to cut the cowl ? ( approx 25 mm longer from head to centreline )
Appreciate if anyone can help with measurements from centre line to cowl side.
Thanks
BIG S
Would a MOKI 210 mount sideways ( like OS160 ) without having to cut the cowl ? ( approx 25 mm longer from head to centreline )
Appreciate if anyone can help with measurements from centre line to cowl side.
Thanks
BIG S
#753


I am in the process of finishing one up with a Moki 2.10 and you will not have to cut the cowl. It does fit in on it's side with no problem but it is a tight fit. Tolerances are very close.
I plan on running a pump on this motor, did you or are you running a pump with yours?
Mike
I plan on running a pump on this motor, did you or are you running a pump with yours?
Mike
#754
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Posting for a friend who is without a computer for a little while.
He's thinking of getting this plane, which would be a move from the 1.20 size plane he has. He's heard though that it can be a little tricky to land because of it wanting to pogo unless greasing the landing. Does it pogo pretty easily if the CG is neutral?
Thanks for the info.
Dan
He's thinking of getting this plane, which would be a move from the 1.20 size plane he has. He's heard though that it can be a little tricky to land because of it wanting to pogo unless greasing the landing. Does it pogo pretty easily if the CG is neutral?
Thanks for the info.
Dan
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I just measured mine for you. From the vertical centerline to the right-side of the cowl is exactly 5" at the plane of the firewall. Due to the right thrust they built in, it might be a little less at the hight point near the glow plug.
#756
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Ive just ordered a yak and am wondering if anyone has thought of useing a 160 glow tuned pipe in the setup. It would mean surgery to the fusilarge but would it be worth the trouble. some at my club think it would. I would like some feedback.
#757

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Privat pilot,
I am considering this exact setup. One of the better pilots at the field today recommended the tuned pipe setup or even a mousse can setup and said it would be well worth it. I currently have a gas engine in mine and though I am very pleased with the power, I really do not like the wing loading. Of course I will then have to buy a new plane for the gas engine
which I really would like to put it in the GP Ultimate Bipe which has about 300 more squares.
I am considering this exact setup. One of the better pilots at the field today recommended the tuned pipe setup or even a mousse can setup and said it would be well worth it. I currently have a gas engine in mine and though I am very pleased with the power, I really do not like the wing loading. Of course I will then have to buy a new plane for the gas engine

#758
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Gday uncas, MAybe we can work something out there is also another idear a canister setup useing a 3w 30cc sized canister someone had one running at my club and it was just as effective as a tuned pipe. the dimentions are 310 mm long and 55mm diameter or 12 inches by 2 and quarter inches. Uncas as you have youre plane there would thet canister fit if a hole was cut behind the engine with the engine inverted. I would also run a perry pump which makes the 160 so reliable
#759
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also uncas is there 2 inches clearance between the bottom of the fuselarge and the undercart ?
#760
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OS 160 version
Guys,
I got a test flight in last night at dusk 30 last night. I had the wrong prop but I went for it. Even with a 16 - 4W I gave it 25% power then around 40% power and off the ground it went.
Took her above 150' and rolled her left. Leveled out the wing and let go of the sticks at 40% power. She was perfect with a full tank of fuel.
I broughter her down only after 2 passes and she did not want to come down. So I gave it 25% power and banked sharp left and she did just that. Pulled power on a wide turn and let her glide in on a very slow idle.
I can only say WOW! Flights light like a hugh foamie. If the weather man is wrong I plan to get some video and push the plane today at our club picnic. Right now I am glad I did not put a heavy gas motor in her.
Crash99
Guys,
I got a test flight in last night at dusk 30 last night. I had the wrong prop but I went for it. Even with a 16 - 4W I gave it 25% power then around 40% power and off the ground it went.
Took her above 150' and rolled her left. Leveled out the wing and let go of the sticks at 40% power. She was perfect with a full tank of fuel.
I broughter her down only after 2 passes and she did not want to come down. So I gave it 25% power and banked sharp left and she did just that. Pulled power on a wide turn and let her glide in on a very slow idle.
I can only say WOW! Flights light like a hugh foamie. If the weather man is wrong I plan to get some video and push the plane today at our club picnic. Right now I am glad I did not put a heavy gas motor in her.
Crash99
#761
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Walter,
Did you get your new GraphTech gear installed? With the 22x8, how much clearance do you have now?
Also wondering if they are the same thickness (if I permanently reinforce the top of the landing gear mount, can I easily change the gear later).
Did you get your new GraphTech gear installed? With the 22x8, how much clearance do you have now?
Also wondering if they are the same thickness (if I permanently reinforce the top of the landing gear mount, can I easily change the gear later).
#763
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2nd flight with a not to smooth landing. But it was not that ruff. Here is the video link. 22.1MB sorry dial up users you do not need to view. But if you have all night feel free.
[link]http://www.eldonmo.com/yak/2.wmv[/link]
Thanks
Crash99
[link]http://www.eldonmo.com/yak/2.wmv[/link]
Thanks
Crash99
#765
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Only the Battery in the firewall box. I did not even have to trim it at all. It was like somewhere between a foamie and any other balsa plane. It was light until the motor quite and the video showed.
Crash99
Crash99
#766
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I left the rudder servo for last so I could balance it and see if it goes in the tail or mid-ship (pull-pull). Boy was I surprised!
With everything installed or taped on, the DL-50 and (7 oz) JTec muffler up front ... the HiTec 5955TG mid-ship (more specs at my website's build page). I got it down to about 5-5/8 inches (middle of wing tube) with about 6 ounces of weight added to the firewall.
Does that sound right? Because of gas engine, no radio/servo batteries or other electronics closer than forward radio tray, right?
With everything installed or taped on, the DL-50 and (7 oz) JTec muffler up front ... the HiTec 5955TG mid-ship (more specs at my website's build page). I got it down to about 5-5/8 inches (middle of wing tube) with about 6 ounces of weight added to the firewall.
Does that sound right? Because of gas engine, no radio/servo batteries or other electronics closer than forward radio tray, right?
#767
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I have mine with the CG at the center of the wing tube also... here she is in the sky performing a knife edge with the smoke system on:
New on the model is the carbon fiber landing gear from GraphtechRC
New on the model is the carbon fiber landing gear from GraphtechRC
#768
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Walter,
Did you get your new GraphTech gear installed? With the 22x8, how much clearance do you have now?
Also wondering if they are the same thickness (if I permanently reinforce the top of the landing gear mount, can I easily change the gear later).
Did you get your new GraphTech gear installed? With the 22x8, how much clearance do you have now?
Also wondering if they are the same thickness (if I permanently reinforce the top of the landing gear mount, can I easily change the gear later).
Yes, it is installed and the clearance is about 5 inches now with a 22x8... more than enough. it is also 3 Ounces lighter.
The CF landing gear is thicker, you will have to do some trimming. But nothing mayor.
Best modification I could have done to this model.
#770
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It is 99% repaired. I cramped one tube on the muffler. Bench tested with no problems. The real test will be in the air.
Thanks
Crash99
Thanks
Crash99
#771
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Last weekend I was at my field, I got there early cause I like to fly when there is no wind and everything is very calm.. There was nobody there either.
I was going to fly my GP Yak54. I placed the model on a special table used for starting engines, after the engine fired up I placed my transmitter on the floor standing up, grabbed the model and placed it infront of me while having transmitter behind me. I then reached to my back to grab the Tx when I accidentally tipped it over sending the throttle stick to WOT!... I saw the plane taking off infront of me and I didn't have any control over it, I wasn't even in the runway yet!.
I had enough time to grab the Tx and lower the throttle stick, but a second after that it crashed right into a concrete wall.
The only thing that looked damaged was the spinner, nothing else had come into contact with anything.
After a more detailed search I found that the firewall has some damage so I'm working on it.
#773
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Great thread
Does anyone have any photos of their DL-50 installation (especially the throttle and choke linkages) in the Yak? Also, any advice from you DL-50 guys about CG balancing? i.e Pull pull vs servos in the tail; and engine standoff lengths? Thank in advance
Does anyone have any photos of their DL-50 installation (especially the throttle and choke linkages) in the Yak? Also, any advice from you DL-50 guys about CG balancing? i.e Pull pull vs servos in the tail; and engine standoff lengths? Thank in advance
#774

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dl 50 is same weight as a da 50 i put two 5925 servos for the pul pull, keep the ass as light as u can and mine is still slightly tail heavy, one day ill take one servo out for the pull pull as i think two is over kill. shift all the electronics forward