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F86 sabre 1/2A

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F86 sabre 1/2A

Post  chevyiron420 on Fri Apr 17, 2015 7:41 pm

My son and I have had some conversations about the need for a small 1/2a plane that is real simple to build and repair. It would be used for practising stunts so it must be able to do some stunting and repairable for the coming figure 9's that will happen. After seeing this video I had to build one, so here is what I have so far.
https://www.youtube.com/watch?v=oX3udmdhw4k


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Re: F86 sabre 1/2A

Post  roddie on Fri Apr 17, 2015 9:01 pm

That's nice Paul! Where'd you get the plans? The fellow in the vid said it's a reduced size Dick Sarpolus design?

I just found a drawing I had in a binder of his 1/2A "Zlin Akrobat".

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Re: F86 sabre 1/2A

Post  chevyiron420 on Fri Apr 17, 2015 10:17 pm

On youtube, not on full screen, scroll down a tad and hit the "show more" button. There are links to the pdf plan. The plan prints at the correct reduced size for a reedie .
Phil
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Re: F86 sabre 1/2A

Post  Oldenginerod on Sat Apr 18, 2015 6:30 am

Have a look at the other CowraMAC youtube links. Looks like those Cowra boys have a whole lot of fun.
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Re: F86 sabre 1/2A

Post  roddie on Sat Apr 18, 2015 7:08 am

Thanks Phil! Got it! What will you be running for a fuel tank? Is there a particular reason why you have the engine mounted inboard?

All of my experience (which isn't a whole lot..) is with 1/2A C/L models that I flew many years ago; back before the internet was what it is today. When the "bug first bit me" back in the early 90's.. I got most of my knowledge from library books.. and a guy I worked with, traded me 5 volumes of the RCM Anthology Series books for a stereo turntable that I had. These were extremely useful in showing better/proper building techniques along with great tips from the "For What it's Worth" articles compilation. In the last few years, I've slowly been building a plans archive. This "Sabre" plan is now saved there!

Thanks again.. and good luck with flying yours!!
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Re: F86 sabre 1/2A

Post  getback on Sat Apr 18, 2015 7:40 am

That sa neat looking build ,the fly was put there too , but I cant find the plan Rolling Eyes  Got the Zlin Though Thanks Roddie! Never mind I found it ..... Very Happy


Last edited by getback on Sat Apr 18, 2015 8:58 am; edited 1 time in total (Reason for editing : Found it !!)
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Re: F86 sabre 1/2A

Post  chevyiron420 on Sat Apr 18, 2015 2:02 pm

roddie wrote:Thanks Phil! Got it! What will you be running for a fuel tank? Is there a particular reason why you have the engine mounted inboard?

All of my experience (which isn't a whole lot..) is with 1/2A C/L models that I flew many years ago; back before the internet was what it is today. When the "bug first bit me" back in the early 90's.. I got most of my knowledge from library books.. and a guy I worked with, traded me 5 volumes of the RCM Anthology Series books for a stereo turntable that I had. These were extremely useful in showing better/proper building techniques along with great tips from the "For What it's Worth" articles compilation. In the last few years, I've slowly been building a plans archive. This "Sabre" plan is now saved there!

Thanks again.. and good luck with flying yours!!
Thanks Roddie, I mounted the engine like that because of the needle valve. With no landing gear it would get broke off every time I slid it in. I posted the question about mounting it backwards and most folks said it would be ok. I set up the fuel tank last night. Its a standard wedge tank, rubber band set up, and its on the opposite side of the engine.
Phil
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Re: F86 sabre 1/2A

Post  Ken Cook on Sun Apr 19, 2015 6:39 am

Doesn't that spraybar press out of the case? I would have concerns in regards to keeping your fuel line as short as possible not to mention the hard bend it has to take to get under the front of the fuse and into the fuel barb on the spraybar. Phil you actually just brought something to my attention that I never recognized until now. My experience with these are very short lived. I never cared much for them and sold all of them early on. Seeing how you mounted the engine on a profile, it was just now brought to my attention of the orientation of the spraybar and needle. Everyone I see is mounted in that the needle would exit the bottom of mounted conventionally. I can't see why it couldn't be flipped around. Is the spraybar knurled where it enters the case to affix it into the casting? I would just be careful if you decided to do so using the proper tooling. Brass is soft and this can mushroom the top of the spraybar if not done properly. Just so your aware, the needles are very soft as well and are EXTREMELY susceptible to breakage. I'm not certain of how the threads were formed on the needles but if I had to take a guess I would say they were cut rather than rolled which is the reason why many of these have their needles snapped off right where they enter the spraybar. Ken
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Re: F86 sabre 1/2A

Post  chevyiron420 on Sun Apr 19, 2015 1:13 pm

Ken, the spraybar passes through the carb at an angle to sweep the needle back away from the prop on all but the very early ones. If you were to flip it the needle would be in the prop. Also memory tells me it wont fit for some reason?
Phil
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Re: F86 sabre 1/2A

Post  GallopingGhostler on Mon Apr 20, 2015 7:31 am

chevyiron420 wrote:Ken, the spraybar passes through the carb at an angle to sweep the needle back away from the prop on all but the very early ones. If you were to flip it the needle would be in the prop. Also memory tells me it wont fit for some reason?
Phil
Nice build and good use of a Testors/Wen Mac .049 front rotary valve. Yes, I've got one of those from E-Bay, unfortunately the NVA was so gummed up with dried Castor that I could not clear it. Now I understand why all those A.C. Gilbert engines that had been stored for years in Castor, which had dried and hardened were mostly unsalvageable until Steve (E-Bay sb1photo) painstakingly took the time to clean them up. (After all these years he's now reached the bottom of the barrel, so those interested in owning one, now's the time to get one. E-Bay #281659914713 AC Gilbert 074 Thunderhead)

It was easy to remove the spray bar as the aluminum is soft enough that the brass assembly came out easily without much fuss. I was going to replace it with another 1/2-A NVA. Yes, where it exits the assembly is angled back away from the prop. Using the Testors short solid non-spring needle might work but in the reverse direction being angled toward the prop would make it dangerous to adjust. One might be able to get away with going to a remote NVA for say a small .10 engine (is there one from a small sized engine?). However this is academic as I have never tried it.

Also interesting is by mounting the engine on the inboard side gives more room to mount the tank. Had an interesting forum conversation with Dennis Lipsett in Brotherhood of the Ring forum. I'm doing similar with my Sterling S-17 profile P-38 Lightning build. I've got 2 Enya .09-III CL engines that have the exhaust on the left side. My 1.5 oz. Kap-Pak wedge tanks are too long to fit. I'm told that fuel suction is not a problem and by mounting the engines on the inboard will get the unmuffled exhaust downward and off the pit guy plus make room for the longer fuel tanks.

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Re: F86 sabre 1/2A

Post  Ken Cook on Mon Apr 20, 2015 2:58 pm

George, I have Dennis's P-38. If you were looking for a tank configuration I could provide some pictures. He just used some Perfect tanks and re plumbed the tubing in a better spot. Ken
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Re: F86 sabre 1/2A

Post  batjac on Mon Apr 20, 2015 5:29 pm

How did Y'all press out the spray bar? I have a Wen-Mac that has a mangled fuel nipple, and I want to replace it with a good spray bar. I have a nice fine thread spray bar and needle from Texas Timers not doing anything at the moment. But, I'd probably just try to put in a spare product engine spray bar/needle assembly I have in the parts box. Either way, I need to get the existing spray bar out. I tried gently pressing it out, but it wasn't happening, so I put it aside for later.

The Attentive Mark
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Re: F86 sabre 1/2A

Post  chevyiron420 on Mon Apr 20, 2015 6:19 pm

Mark, Its been way to long, but I think I remember the spraybar having a flange on the hose nipple side. It has to press out from the threaded side. I think you can use an assembly from a pipe bomb. It is not exact but it can be made to work. The threads on the bomb unit are poor and will leak with out the hose to seal it.
Phil
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Re: F86 sabre 1/2A

Post  GallopingGhostler on Mon Apr 20, 2015 7:20 pm

Phil is correct, there is a one-way direction to move the spray bar out. I don't remember if I used the flat side of a block of steel and pressed against it or used a pair of needle nosed pliers, protecting the aluminum from scarring with a bit of cardboard to insulate from harm. It came out easily. I've got a spare 290 horseshoe back. I might see if I can salvage the NVA from it. I know it is not as fine thread as the 290 postage stamp back, but I think it should still be able to work.

If I go this route, will test and provide a report with photos. If successful, may be an option for others to try.

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Re: F86 sabre 1/2A

Post  chevyiron420 on Wed Jun 03, 2015 5:39 pm

Today was the first time I ran it as an assembly. I have been holding off, wanting to put some colour on it, but not knowing what to do. I finally said the heck with it and am going to leave it the way it is. The engine ran a very steady 15500 as I expected. I have other testors engines that are faster but this one has a strong fuel draw. The RPM stayed steady horizontally or vertically like I wanted. She ran 3 min 35 seconds with this tank, and I thing thats enough for now. I do have a longer tank that fits if needed. I cant wait to get to fly it, if I can. I am so unstable of my feet now days. The last time I fell down and crashed my baby ring, but it and I were ok.  


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Re: F86 sabre 1/2A

Post  GallopingGhostler on Wed Jun 03, 2015 10:14 pm

Looks good, chevyiron420, can't wait to see a flight report.

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Re: F86 sabre 1/2A

Post  getback on Thu Jun 04, 2015 7:18 am

Yep Looks good and strong to , get out there and have some FUN Very Happy
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Re: F86 sabre 1/2A

Post  rogermharris on Thu Jun 04, 2015 7:53 am

that's a sleek looking bird! i really like it left clear.
hope you can get out and enjoy it without incident.
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Re: F86 sabre 1/2A

Post  roddie on Thu Jun 04, 2015 7:33 pm

Really nice Phil! That's gonna tear-up the sky! I like the solid lead-outs. Are they .025 m/w? How long and what type lines are you planning to use?
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Re: F86 sabre 1/2A

Post  chevyiron420 on Fri Jun 05, 2015 2:58 pm

Thanks guy's. The leed-out's are .020 m/w. I guess I'll start with 35 foot dacron lines and go from there. I do have a set of .008 stainless lines that I used for my baby streak, I may try them.
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