RE: Aviation Models 33% Yak Build Thread
[quote]ORIGINAL: Flyinhi1 [quote]ORIGINAL: jrjohn Did you notice a decrease in vibration? I sure did [/quote] You know, I never thought my engine vibrated as bad as I'd heard others did. It does run smooth - I guess smoother than it did before. After talking to Dave Johnson of DA at the TAS I changed my fuel to 91 octane, also. I don't have a twin to compare it to, so my experience
Posted on: 10/24/2009 10:39 AM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9198221

RE: Aviation Models 33% Yak Build Thread
Did you notice a decrease in vibration? I sure did
Posted on: 10/23/2009 9:59 AM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9195741

RE: Aviation Models 33% Yak Build Thread
[quote]ORIGINAL: diamondave i got the large volume wrap around pitts from jtech on my zdz80 and its not that loud, i think it sounds good, i know my buddies da85 with the small pitts muffler on his sukoi is pretty darn loud though [/quote] I bought the small one because I didn't want to cut the bottom of the cowl too much, it's louder than hell
Posted on: 10/16/2009 4:25 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9178528

RE: Aviation Models 33% Yak Build Thread
The reason I didn't put the can in, is because I would have had to cut the bottom of the firewall away or hack up the tunnel just to get the can in. The tunnel is large enough to slide the can straight in, but not at an angle. Anybody installing the MTW110k can would want to do this before the firewall is glued in place, and then hope they never need to remove it. The MTW110K can is the correct canister for the DA-85. I'm not sure what the other engines use, a narrower canister would go in without any trouble. john
Posted on: 10/15/2009 10:50 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9176878

RE: Aviation Models 33% Yak Build Thread
[quote]ORIGINAL: RVBlack jrjohn, did you ever get a picture of your yak with the can setup? show and tell me about it. RV [/quote] RV, I didn't go with the can setup, I went with the J-tec pitts muffler, I wish I didn't. It's way to loud. I'm seriously considering swaping it out for a can. If you still want pictures, I can take them next time I pull the cowl off for inspection
Posted on: 10/15/2009 10:00 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9176747

RE: Aviation Models 33% Yak Build Thread
[quote]ORIGINAL: frieshoo Wow. Good to see this thing still going. I bought my 33% Yak back from a buddy a couple weeks ago. It's stock (no carbon) with a zdz 80rv/pitts muffler/Xoar 26x10. With A123's it weighed 22lbs on my digital scales. I hope to fly it next weekend. It's in great shape for a 4 year old ARF. [/quote] Sounds like a nice setup, the weight is good too. You will love this plane John
Posted on: 10/15/2009 10:45 AM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9175106

RE: Aviation Models 33% Yak Build Thread
[quote]ORIGINAL: Flyinhi1 I hope so, like I said though, mine didn't give me any indication ever, that something was wrong - - no loose muffler, no broken joints in the airframe from excessive vibration, started easily every time, no dead sticks , great power......I was sure I was going to be the exception to to what I'd been hearing for some time about this engine. Then boom! (actually - abrupt silence) and too low and slow to do much of anything except roll upright (I was inverted at the time) and pull full high rate elev. to flatten her out for the inevitable drop. Plopped down nearly perfectly on all three wheels, broke just the tip off one blade of the mezjlik prop, broke the spark plug in two and split the plug boot. Slightly bent the outer corner of the head cooling fin and gound in some surface asphalt from the runway to a couple other high spots around the bent fin. Pretty much a direct impact to only the top of the engine. Almost didn't even think it needed to go back to DA, but since I needed them to fix the ignition plug boot I brought the engine along with me down to DA just to see if they could do a quick check. A few days later I called to see if it was ready and they said the crank had been pushed back into the case and they had done all this work to it. I'm fine with it that they did it, but it sure didn't seem like that crash would produce the damage they said they found. I know I've pounded my 50 in a lot harder than that and never took it for a check up and it runs damn good and smooth. Just lucky there I guess, no? [/quote] Hows the 85 running now?
Posted on: 10/13/2009 12:52 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9169739

RE: Aviation Models 33% Yak Build Thread
[quote]ORIGINAL: Flyinhi1 Hey guys, just found this thread. I'm Dave's friend with the injured Suk.....DA did indeed do the carb spacer, mid and front bearings, shim, c-clips, piston, ring, steel bolts,etc. Basically have a nearly new 85 again. Not sure what to think about all this since I have papers from when I took it for known upgrades around this time last year. Never started it until June-July of this year. Hope your on to something John if it was an air leak. Also, even though I didn't think it was that bad to begin with, if the newer piston helps with any vibration issues, that's just icing on the cake. I've got to wait til after the Shootout to be able to fly this plane again, so we'll see how it all goes. Like my name says, I'll be Flyin High until I get comfortable with this engine for a while. Never had any problems keeping it turning until this happened. [/quote] Sounds like they did the exact work to your engine as they did to mine. Your going to be very happy with the decrease in vibration! My muffler doesn't come loose anymore. I know how you feel about flying high. Before the upgrade I never made a landing with the engine running. I had to fly high enought assuming every landing was a deadstick. After the upgrade it has never quite. I'm down on the deck again! Now I love this motor. I should have called DA right away, rather than waiting 3 months.
Posted on: 9/25/2009 9:16 AM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9122668

RE: Aviation Models 33% Yak Build Thread
I'm guessing if he looks on the list of repairs, he will find that they installed a metal intake spacer that is supposed to get rid of the air leak. It would be good to know if they made this modfication
Posted on: 9/24/2009 12:41 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9120479

RE: Aviation Models 33% Yak Build Thread
I said that wrong in my previous post, Mine was the same as your friends, it would quite when going from idle to throttle up. I'm sure it was the intake leak that caused this. It's perfect now.
Posted on: 9/23/2009 10:57 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9119339

RE: Aviation Models 33% Yak Build Thread
Previous to sending the DA85 in, it would deadstick on nearly every flight while changing the throttle setting to idle. Idle mixture screw was at 2 1/4 turns and still to lean, I'm sure it was an air leak on the intake as that is one of the things they fixed with a metal spacer. Since the fix I have not had one single deadstick. They got rid of the vibration with the newly designed piston as well.
Posted on: 9/23/2009 12:25 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9117971

RE: Aviation Models 33% Yak Build Thread
This TOC 33% Yak is one sweet flying plane. My Da-85 had lot of issues. DA straightened everything out. Air leak on the intake, different piston, changed timing, bearings ect. Now it runs perfect. I've never seen a plane that needed zero coupling on knife edge. The DA-85 is over kill to say the least.
Posted on: 9/22/2009 10:17 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9116690

RE: Aviation Models 33% Yak Build Thread
Dave, I have a Jtec on my DA-85, real nice quality and very lite. All the seams are tig welded. So far so good. Maybe 10 flights. I forget the guys name at Jtec. Seems liks a nice man.
Posted on: 5/8/2009 10:36 AM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8751201

RE: Aviation Models 33% Yak Build Thread
I had heard the same thing about the DA-85 (excess vibration) As it turns out, it runs quite smooth. I was pleasantly surprised. However I have not done a side by side comparison. I think the real key to low vibration on the DA is to have the correct engine mount/spacer. Anything less than what is recommened and you could have trouble
Posted on: 4/26/2009 9:39 AM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8716198

RE: Aviation Models 33% Yak Build Thread
[quote]ORIGINAL: pliebo I got to fly mine yesterday for the first time in over a year. Problems with the zdz super 80 had me grounded, then I got a megatron starter. Man how nice it is to not be flippingflipping flipping all day. Anyway the plane flew as great as I remember it being! I'm tempted to put a DA 85 on it as the zdz is still running rough and won't smooth out. everybody seems to be pleased with the performance of the da 85? [/quote] The performance of this plane with a DA-85 is off the charts. Lots of throttle curve, and then throttle management.
Posted on: 4/26/2009 8:53 AM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8716132

RE: DA-85 not running good!!!!
[quote]ORIGINAL: flygilmore I am wondering why your engine needed "updates" when the 85 is a "brand new" offering from them??????? I have read so many times of folks sending their DA engines in for various maintenance reasons and receiving so called "updates"[8|]... what gives? I don't ever read of any other manufacturer having to provide updates to their products. [/quote] I know your not refering to my post about the Updates, however I think I can answer your question. Yes DA has had updates in the past. A lot of DA-50's had to be sent back because the crank pins were not hardened correctly and were failing. I had one of the failures and sent it back. I guess the got a bad batch of pins. As for the DA-85. Yes, "brand new offering" is really the key to the entire issue. I think anytime you build a totally new engine from scratch, you have to expect there will be some necessary changes/updates. Sure they test a few engines, probably put quite a few hours on the test engines in hopes of heading off future problems. But nobody does testing like John Q Public. Thats where things really get shook out. Lots of abuse that the factory guys would never think of putting an engine through. Overheating, crashes, not enough oil, too much oil, poor mounting, out of ballance props, over revving just to name a few. Believe me, if there is a weak spot, the public will find it quickly. ( and evedently they did) I know one update had to do with the drive washer pushing back into the crankcase, I think it had something to do with the front bearing sliding back. Now I hear something about the red anodized carb bolts being replaced. Not sure it it's true, mine still has the red ones. I assure you mine won't be sent in just for different bolts. As for other engines, Not sure if your talking about the DL's, and don't get me wrong I love the DL engines!, However they are for the most part copies of the already perfected DA engines. Unless they get some faulty parts, the should not need "updates" Hope this helps John
Posted on: 4/13/2009 7:52 AM by Author "jrjohn" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=8676161

RE: DA-85 not running good!!!!
Just got back in the house from 20 minutes of testing. You were right! I actually held the plane myself while sitting on a chair with the transmitter right next to me. You must have married a different type of woman than me, my wife was not interested in early morning engine testing. Needles were both 1 1/4 to start. Transition was perfect right side up. I held the plane upside down and advanced the throttle quickly, it would quit every time. If I advanced it very slowly, it would sputter and finally rev up. A quick advance was sure death. I kept increasing the low speed 1/8 turn time after time with the same response, I was about to give up and try leaning it when suddenly at 2 1/8 turns it was nearly perfect. I didn't have time to do anymore testing right side up as I need to get to church, I'll put more time into it later, I'm guessing it's going to be fine once I adjust the highspeed a little. This engine really starts great, even better than my 50's John
Posted on: 4/12/2009 2:28 PM by Author "jrjohn" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=8673292

RE: DA-85 not running good!!!!
One more question, you said that after you richened it up on the low end, it solved your deadstick problems, however the transition when right side up was only so so. I understand DA sent you a new carb. How does it transition when right side up? better, same, worse??
Posted on: 4/12/2009 9:19 AM by Author "jrjohn" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=8673124

RE: DA-85 not running good!!!!
I'm going to take your advise and do the same as you did, I'll start the thing up with the wings off and hold it inverted while my lovely wife works the throttle. She likes to be in control so this should work well. I'd swear it was running rich on the low end and loading up with fuel like the DA-50 used to do. However I'm now thinking your right. I"ll have this shook out today and report back later in the day. Thanks for the help John
Posted on: 4/12/2009 9:13 AM by Author "jrjohn" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=8673114

RE: DA-85 not running good!!!!
just finished my 33% TOC Yak with a DA-85, took it out for the first time today. Started off very rich. Started out at 1 7/8 on the highspeed and 1 1/2 on the low speed. Everytime I tried and inverted elevator the engine quite when I tried to add power in from an idle. 2 deadstick landings Leaned the highspeed to 1 1/4 The engine didn't blubber nearly as much, however another deadstick when I added power during an inverted elevator. Leaned the low speed to 1 1/4 kept the highspeed at 1 1/4, another deadstick while inverted, any ideas? Awsome power, engine runs and starts great until inverted and transitioning from idel to high power. Carb is tite, new fuel lines, clunk is intact, Inverted flight is fine with power Any idea's? john
Posted on: 4/11/2009 9:48 PM by Author "jrjohn" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=8672053

RE: Aviation Models 33% Yak Build Thread
Yup, love the 3W props!
Posted on: 3/22/2009 9:44 AM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8603131

RE: Aviation Models 33% Yak Build Thread
My 33% is finished and ready to fly, we just need the snow to melt. Fired the plane up yesterday. The DA-85 starts and runs real nice. The engine runs very smooth. From what I was reading about the 85, I was worried it was going to have excessive vibration. Thats absolutly not the case and it pulls like a horse as well. I'm using a 3W 26x10 prop, didn't tach it. I can't wait to fly John
Posted on: 3/21/2009 9:52 AM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8600115

RE: Aviation Models 33% Yak Build Thread
[quote]ORIGINAL: P-Diddy It would have enough power for sport flying and mild 3D since it probably puts out around 40 lbs of thrust, (someone correct me if I'm wrong please) and the 35% Yak would be around 27-29 lbs. You would likely be able to hover it and do most of the maneuvers, you just wouldn't have the strong pull-out that you would have with the 33%. Since the 35% is designed around the 100cc class, I imagine there is enough room for two tubes. Again, if someone knows otherwise, please correct me... -Pat [/quote] I have to agree with Mr. Diddy. I think it will be fine for the sport flyer, but if your talking 3D, you need a DA-85 or better yet, the new DL-111 john
Posted on: 3/19/2009 7:55 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8595440

RE: Aviation Models 33% Yak Build Thread
[quote]ORIGINAL: ottertok Hi guys, I have a new 3W 85B2 QS twin with headers and cans and I was wondering if this plane will accept two cans and would this be a good plane for my engine? [/quote] You will not fit two cans in that plane unless they are extremely narrow
Posted on: 3/18/2009 11:08 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8592816

RE: Aviation Models 33% Yak Build Thread
[quote]ORIGINAL: wind junkie [quote]ORIGINAL: jrjohn Today I weighed my plane on a 33# limit Peloze digital scale. I could not believe my eyes. 20 pounds 3 oz I'm going to a buddies house on Friday to have him program my servo's, if he has a scale that goes high enough we will check it on his as well. I don't use a spinner on my yaks, or the wheel pants. John [/quote] That seems
Posted on: 3/16/2009 10:49 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8585879

RE: Aviation Models 33% Yak Build Thread
[quote]ORIGINAL: diamondave are those mixture screws right at the firewall? i had that happen with my zdz100 on my 110yak, i had to cut some of the top away, not through but made it kinda thinner, then i can use a long skinny screwdriver to reach in on kind of an angle to get to them [/quote] dave, yes one is right in the center of the firewall, one is slightly behind. I carved the firewall at an angle and put a small hole in the side of the engine box so I can get at it with a screwdriver. Cut a hole in the top of the engine box so I can see what I'm doing. The cowl will have to be off to make adjustments. I hope I can set it and forget it. John
Posted on: 3/16/2009 10:43 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8585853

RE: Aviation Models 33% Yak Build Thread
Today I weighed my plane on a 33# limit Peloze digital scale. I could not believe my eyes. 20 pounds 3 oz I'm going to a buddies house on Friday to have him program my servo's, if he has a scale that goes high enough we will check it on his as well. I don't use a spinner on my yaks, or the wheel pants. John
Posted on: 3/16/2009 10:27 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8585792

RE: Aviation Models 33% Yak Build Thread
Jtec exhaust, note the safety wire
Posted on: 3/15/2009 8:21 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8581534

RE: Aviation Models 33% Yak Build Thread
Inside the engine box, Custom JRV back washers, and no extra threads on the bolts
Posted on: 3/15/2009 8:17 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8581516

RE: Aviation Models 33% Yak Build Thread
How about a manual choke on the DA-85?, it can be done. Nicest working choke I have ever made. Idea came from my buddie JRV
Posted on: 3/15/2009 8:11 PM by Author "jrjohn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=8581485