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Mar 11, 2016, 06:35 PM
Play that funky music right
kenh3497's Avatar
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I only have a 4 pound scale so I weighed the parts and pieces. I'm going to have a 10# + airplane if I use the YS 120. The 91 is not light enough to make 8 1/2 pounds. I have yet to cover the fuse and paint the front turtledeck and cowl. I'm a bit concerned with the plane being nose heavy with the 120. I guess I could stick the battery in the tail.

I feel a much lighter plane could be built if balsa was used in the fuse instead of the 100% ply fuse. I think the wings could be lightened up a bit also but would need to visit that a bit. Lighter wood would go a long ways.

This Bucker came to me framed up so there was not much i could do to lighten it.

Ken
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Mar 11, 2016, 07:52 PM
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The light ply is not as bad on weight as you may think. That airplane has 1,180 sq in of wing so 10 lbs is still a pretty light wing loading, it's just a bit much for a .91 if you want more vertical then a sport airplane. By comparison my latest bipe weighs 9.5 lbs and is 100 sq in less but flies very light. Power is a YS 140 DZ which I refer to as insane vertical for this airplane. I did have to mount dual elevator servos in the tail to get it to balance though. I really think you would be happier with the 120 as my understanding is that you want to persue some pattern type flying with this airplane. Pattern requires more power then what one would initially think, even at the sportsman level.
Mar 11, 2016, 10:11 PM
Play that funky music right
kenh3497's Avatar
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Canopy latch is complete. Might add a stop for the latched position but will ponder that a bit yet. Need to add some blocks or "something" for the latch rods to glom on to, to hold the canopy shut.

Now I can continue with the build. On to mounting the motor, throttle servo. Once that is done I can cover the fuse and paint the front turtle deck and canopy frame.

You may ask why go to all the work of a latching canopy. Well, it was practice for my Kraft Super Fli build which I fully intend to get back to.

Ken

EDIT: I was unsure how I wanted to attach the handle to the shaft. I drilled the shaft for a screw i found in my junk drawer but did not tap the hole for the screw. I split the shaft and then slid the handle over the shaft. I then installed the screw and let it "cut" it's own thread and in the process expanded the shaft locking the handle in place. Simple and removable!
Last edited by kenh3497; Mar 12, 2016 at 10:13 AM.
Mar 11, 2016, 10:15 PM
Play that funky music right
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Quote:
Originally Posted by exf3bguy
The light ply is not as bad on weight as you may think. That airplane has 1,180 sq in of wing so 10 lbs is still a pretty light wing loading, it's just a bit much for a .91 if you want more vertical then a sport airplane. By comparison my latest bipe weighs 9.5 lbs and is 100 sq in less but flies very light. Power is a YS 140 DZ which I refer to as insane vertical for this airplane. I did have to mount dual elevator servos in the tail to get it to balance though. I really think you would be happier with the 120 as my understanding is that you want to persue some pattern type flying with this airplane. Pattern requires more power then what one would initially think, even at the sportsman level.

I'm not so sure I want this for a pattern plane though I think it would do well in the bottom two classes. Surely something to consider! I was thinking more along the line of a 1.20 to 1.40 size mono plane. Was/am thinking about building one of the InSite versions. On the other hand, it seems biplanes are becoming VERY popular in pattern.........

Ken
Last edited by kenh3497; Mar 11, 2016 at 10:20 PM.
Apr 05, 2016, 03:11 PM
Registered User
Nice to see this thread picking up again...

I wasn't too happy with the Saito 125 I flew it with last - still didn't seem enough power.

The distance of firewall to prop driver is 125mm so this limited the choice to a OS 155a or a Saito 182. I went for the Saito because although it weighs 1kg it doesn't need a mount and the exhausts are just lightweight staight pipes. So I reckon little or no additional weight over the YS91 (750g without exhaust)

The biggest problem was fitting the cowl - because it tapers to the front I had to cut big holes each side. Still that saved some weight. I also had a super light cowl made by Carbon Copy in the UK. Initially they sent me one that weight nearly 500g, but they worked hard make one much lighter <200g if I recall.

Not flown it yet - weather still challenging.

Having said all that I have a YS110 in a H9 Christen Eagle and that gives loads of power with 16x6 on 20% - that might be an option.

Dave
Apr 08, 2016, 08:18 PM
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I have my YS 120NC hanging on the nose of the Bucker now. The cowl was long enough so I decided to jump in with both feet. My only concern now is that it may be a bit nose heavy. I can put the RX battery almost to the tail if needed as there is a hatch intended for the elevator servo about half way between the trailing edge of the wing and the tail. My elevator servo is under the canopy floor along with the rudder servo.

I'm moving ever so slowly forward. I need to fuel proof the fuse forward of the wing and I should then be ready to cover the fuse. Paint for the fiberglass parts will have to wait for warmer weather. Our "normal" highs are supposed to be around 50 this time of year. Today it snowed and the high got to a blistering 34. I was blessed to work outside all day in it, with a 30 gusting to 35 MPH wind. YUK
Apr 11, 2016, 09:08 PM
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A little progress. Both wings covered, elevators and rudder covered, Canopy opens and closes with a latch, Cowl mounted but needs the engine opening cut out, Throttle cable installed but need to build a mount for the servo. Fuel tank relocated back to the CG and secured. I need to fuel proof the inside of the fuse and I think I'm ready to cover. The fiberglass parts get painted hopefully to match the plastic cote.
Mar 26, 2017, 09:39 PM
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Getting closer. Non scale decorations but should be visible in the air. I kind of jumped ahead of my self a bit by painting the cowl before I got it cut for the engine. We are having a Mall show next weekend so wanted it ready or not for the show. All that's left is the engine installation, glueing the clear part of the canopy in and adjusting all the control linkage.

Ken
Apr 08, 2017, 09:51 PM
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It's a good thing I took the Bucker to the mall show. One of my club mates noticed the top wing was not square to the bottom wing. The left side was about an inch or so in front of the right. I took great pains to square up the bottom wing to the fuse and must have assumed the top wing would fall into place This should be an easy fix as the cabanes are bolted together. I just need to loosen the bolts and tweak it and then retighten the bolts. I hope I don't need to remake the outer struts (interplane struts?)

My Pattern plane is finished so I should have a bit more time to work on the Bucker.

Ken
Apr 25, 2017, 09:32 AM
ken kalynuk, winnipeg CAN
kenair's Avatar
Good luck on flying your Bucker, I'm adding a few photos of the one I have, I re-decaled it this winter to give if a vintage RAF look. I'm it's third owner, the model has to be 10 years old and still going strong, The first owner used a Quadra 35 gasser, the second owner put in a Brison 2.4 gasser which is on it.
Model flies better that whan I can do with it.
cheers - ken
Apr 25, 2017, 12:27 PM
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Looks good Ken! After straitening up the wings I wound up remaking the wing struts. I also need to rebuild the link between the ailerons. I'm done fussing with the wings at this point. I'll be moving on to installing the YS 120 in the next few days.

Ken
Apr 25, 2017, 03:20 PM
Registered User
Have a MVVS/Evolution 26cc gasser in mine; needed two tail mounted elevator servos to balance out but flies super. Been flying it for several years now.
Jul 30, 2017, 08:02 PM
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It flies!!!


After a false start last Saturday, I was able to get a proper maiden on the Bucker today. Four flights total I do have one little problem though. One of the stripes on the lower wing was ripped partially off. I had a little trouble getting the stripes to adhear without bubbling. I guess I didn't use enough heat to get a good seal.

The YS 120 was purchased used, but from the looks of the internals I can't imagine it has more than a tank or two through it. By the end of the fourth flight it was running much better. The cowl is still off to facilitate easier tuning. I think the cowl will go on at this point. Only 16 screws hold it on

It may be a bit premature to judge the flying characteristics but so far I'm impressed. The YS provides more than enough power and it flies really nice. Only 4 clicks of aileron trim and three clicks of elevator need to have it flying strait and level. My landings are still a bit fast but the plane handles so nice landings are looking pretty good already

The Photos are before the final assembly took place but they give a pretty good idea how the plane looks.

Ken
May 29, 2019, 10:09 PM
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bee banger's Avatar

Great job and power recommendations


Thank you for the the great build thread first of all. For all those contributing all the power options and objective remarks on how they perform with those engines. And for knowledge that many builders are still at carrying this design forward. I am building a couple of these and have seen so many 15 year old posts that I thought I was the only one who was still passionate about this timeless performer. I am going for OS 1.20AX's with Power Box muffler on the 90 degree adapter.

Found one of these models built but never flown. Managed to locate a set of plans but no manual. Not a necessity but a manual is nice to have. I will have redesign the wings to accommodate a scratch build. Luckily the model was not covered in any serious way. The first flight would have got rid of it. And it was so sparsly glued that it was easily and cleanly knocked apart to make templates from. The light ply construction is as light and strong as any style of building and material combination. Simple and effective. Currently building the Pilot 1 to 3.5 Bucker Supermann . Both the CG and Pilot are accurate in cockpit configutarions as Jim Moser had the same aircraft in both. It is currently a 2 holer again. This point had me confused years ago, so I though it was note worthy.
Great Work Gents!
May 30, 2019, 11:31 AM
Registered User
Twenty some years ago the owner of one in Medford Oregon let me fly his 1.20 4S plane after a pylon race. It was so good that I bought a kit after returning home. The wings use a fairly thin section and unlike many biplanes, it had a good glide. As far as acrobatics, it is quite capable, and it tumbles end over end very well. Mine is half assembled, it needs the wings built so I can make rib templates. Too bad so many of these designs were bought up by the evil empire only to be discontinued.


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