The CG in the manual states 185mm from the LE. This is a PROMINENTLY tailheavy state.
The addendum on the new sabre I just got says 160mm. That's a big difference.
Wonder how many "unflyable" sabres got trashed due to this blunder by Kyosho? The thing a a little beastie with an aft CG, aok when set correctly...

Yes that is a huge blunder by Kyosho not to get the C.G location right for this jet. It would be a terrible shame for this blunder to give a bad name to this plane and squelch developemnet of more small D/F planes. I got one of the later versions with the addenum. I fly mine at 175mm and would not recomend it be futher aft since stablity seems to be close to the neutral point here.

Hi You all:

Finally got around to having the second flight on my Kyosho F-86 made this afternoon. Density altitude was as close to sea level as you can get in West Texas this afternoon.

Fueled the little bugger up with racing fuel (65%) and Summitt120 took over the tx. The little airplane STILL waddled into the air. Oh, BTW, the CG on my F-86 is at 165mm based on what I read in the Flying Models article a few months ago. I also had a friend of mine bend the LG out (like at Superman 2001).

Mike did a great job of keeping it from stalling out and managed to land it further down the runway. The model never got above eight feet in altitude this afternoon.

I've done all that I can to improve flight performance while keeping as close to base stock as possible. If I keep this model, the next thing to do to it will be to cut those cheater holes in the wings on either side of the Ail. servo. If that doesn't work, then the pull-starter has to come off and I figure out some sorta of starter wand that can be stuck up the snout without snagging on the wires and tubes inside.

shanksow,

Sorry to hear that your Sabre didn't fly well. You used the word "waddle" to discribe the flight performance. A waddle implies cylclic side to side swaying. This could be caused by alternate side to side tip stalling.

The second big mistake Kyosho made with their Sabre was in the manufacture of the wing. They were built with wash-in (the tips of the wings have a higher AoA than the roots). This is just asking for trouble. Also, wash-in on a swept wing like the Sabre produces a "down elevator" effect that the elevator has to fight resulting in a lot of performance-robbing "trim drag". Here is a picture from the construction manual to illustrate what wash-in looks like on the finished model.

This is how your wing tips should NOT look!!!

There is a pronounced washin in this photo af about 2 degrees. If your wing tips look like this your Sabre won't fly very well. I corrected this on my Sabre so that, from a side view like this, the bottom of the wing tips are parallel with the bottom of the aft fuselage. Also, drooped ailerons can produce "induced washin". So, reflex the ailerons up a bit.

In my testing, I didn't find any rpm improvements beyond 30% nitro. I don't know what effect altitude has on nitro content though. I'm at about 700'. The cheater holes on the bottom of the wing sound like a good thing to do. Given that your wing tips have the proper AoA, I would think that you should have a very flyable (not a hotrod) airplane with a thrust to weight ratio as low as 1 to 3. If you could do some static thust tests, that would determine if there is a serious lack of thrust .

I apologize if all of this is just a re-hash of stuff you already knew. Hope something here will get you some enjoyable flying time with your Sabre.

My 2 cents. I think Kyosho should: A: get the instructions and wing right. B: give a rebate of somekind to the guys who bought up and lost all the mislabled ones. C: Have an upgraded OS .25 DF motor included in all future ones.

shanksow, it will not fly that good without the plastic half moon thrust tube that you can make out of any light plastic and c.a. it in place. then take the plane out and try to fly it. this mod took me 5 minutes to do with some plastic that I had in my work shop. If you look into the back of the plane all of that high velocity air after the fan is wasted in that big open aera. you have to cut this area down to the same size of the fan. I did put the cheater hole in the wing. This mod will not make it a speed demon, but it is lot better than the stock. go to Re: http://www.teamrcpilot.com/ and at bottom of the page will take you to see my mods. good luck [email protected]

Thanks guys -

I'm debating with myself if I want to invest anymore time and effort on this model. I have been looking around for what would appear to be the right type of 'plastic' soda bottle to convert into a thrust tube. There would appear to be several holes that will need to be cut into the bottle at certain spots just for the control rods, etc. ( how many? Five plus?)

I'm also trying to psyche myself up to the point of actually start cutting on the wing. I have not reached that point yet.

The washin was the primary problem with my first KF-86. This second one is better in the wing tip department. Also, talking with Summitt120 after the last attempted flight, Mike pointed out that he thought (I agreed) that using the 40% fuel, the model had better flight performance than this last attempt using the 65% racing fuel.

I guess thats enough for tonight. later.

Shanksow,

Think of the "thrill of victory" when you get your Sabre to fly well knowing that it was your hard work that made it happen. Sure, it is possible to just buy a BVM Sabre or some other well established ducted fan aircraft and be virtually assured of success because all of the design tweaking has already been done but, there is nothing like the thrill of pioneering your own tweaks to produce a better flying craft. Of course there is always that "agony of defeat" thing but, as they say "nothing ventured, nothing gained".

I think what t33jetman means by "half moon" thrust tube is "partial" ducting of the lower half only. Don't try to duct around the complicated stuff up top. Looking at t33jetman's pictures of his ducting, it looks like his ducting is actually more than a half moon. Going clockwise from a rear view, I'd say it looks like his ducting starts at 3 o'clock and ends at 11 o'clock. This avoids all the complications of the control rods and such. From my test stand experience, I can say that the 3 to 11 o'clock area is the area of the fastest efflux from the fan because there are no obstructions there (head and pipe), and would therefore benefit the most from ducting.

Craig, You are right on the shape of the plastic I used for the thrust tube. I did not want to get into getting around the top stuff and it would have taken more time to do, I just wanted to fly better with the guickest fix with as little work to do in one day. 30% nitro is all that I use and I never lean out all the way and my engine has never quit unless I run it out of fuel. slide it in place and do some static test and see if it shows improvment for you. There is no cost to the fixes that I did it just took about 2 hours for all of them and I went to fly the plane. If you want to get rid of it give it to me and I will put a turbine it for my second plane. I hope you try some of these fixes because we all want everyone who has one to have as much fun as I had with it at the close of last years flying season.

William

After it crashes (and it will), let me know and I will buy your engine and fan out of the debris. I plan on making a small cartoon scale A-10 with my engine and another I buy off of another failed F-86. Thanks.

I saw this Kyosho Sabre fly last fall along with the Kyosho Gee Bee. They are plain and simple junk. If pigs could fly, the characteristivcs would be the same. No power at all, Both these planes are at their best when about to stall out. There are to positive notes here, The first is they do look good and the second is i do not own one.

HOOAHH!!!

To Craig & t33jetman -

Thanks for the info about the 'half' moon part of the thrust tube in t33jetman's F-86. I couldn't really tell how it was arranged in the stern view photo that was presented.

I'll be in this funk for the next week or two; then come out of it and get back to work on the 'Great Science Experiment.' The guys here in Lubbock know what I'm talking about (the little jet), when I start saying "the great science experiment."

Shanksow, On that thrust tube, I just curved a plastic sheet to fit into the back of the plane, and pushed it in till it reached the fan unit, and while holding it in place I dropped c.a. in around where it touched the fan to hold it in place. I trimmed the back in to shape of the rear of the plane and dropped c.a. around the edges to hold it in place. The plastic dose not reach around to the top of the fuse. to make it a simple installation. I put the cone on the end to drop the exit down from 3in. to 21/2in. and c.a. it into place. My first thrust tube was made out of balsa and c.a. thin wicked down into it. It took 5 min to make and install this.

well i gues my F86 and easytigers flew great , i live in southern california , i had no problem , 30% power master heli fuel in the middle of the desert at aprox. 2500 feet alttitude , it did take alittle time to take off aprox. 100 Feet , i let it build some speed nice and level and turn right , and she was on step after that , iwas able to get the little F86 so high that i need it to bring it down cause i was losing site of it , and this one is stock ,for those that dont believe , Me and my bud that also has one of this little buggers ,will be at the tucson rally this weekend ,so come and see for your self .Ed

That's GREAT! You don't need to actually buy, own, or fly a model to give an EXPERT opinion on it! God bless the internet, where everybody knows everything about anything!
What else is plain and simple junk? Please give us five more expert opinions about five more planes you have never known or flown.
This is the internet at its best!

Mavdriver, I wish that I could bring my little F86 to your meet this week and do some racing in the air with you guys, those of us who seam to have fun flying this thing and getting it to fly without crashing it into the ground. I Hope you guys put on a good show with you planes.

[email protected]

That's GREAT! You don't need to actually buy, own, or fly a model to give an EXPERT opinion on it! God bless the internet, where everybody knows everything about anything!
What else is plain and simple junk? Please give us five more expert opinions about five more planes you have never known or flown.
This is the internet at its best! Hey Easy well said . Ed

Mavdriver, I wish that I could bring my little F86 to your meet this week and do some racing in the air with you guys, those of us who seam to have fun flying this thing and getting it to fly without crashing it into the ground. I Hope you guys put on a good show with you planes.

thanks t33jetman , we will have a good time , and by the way i am not a kyosho rep , i just happen to like the airplane . Ed

i wish i could go Ed, so that we could compair the two one with RK20B fan and one Stock(

Mavdriver, I am not a rep also, but I like the concept of the plane, and I know with my skills that I could make the little plane over come some of its built in flaws and have some real fun with it and pass on to others what I found out to help anybody who also liked the plane. I know I can make a 100mph plane out of the frame easy, but that is what my two big planes are for so that I can see them better. I didn't pay full price for the one I got but I sure put some time in it to make it fly so my hobby store could sell some . To all I heard today that the turbines for this will not be coming out : cost will be too high to sell, tolerances on the fan too critical, but you may see a guy flying one for AMT turbines who designed one which is flying great.

Well put your money where your mouth is smart guy and go buy one. I like the guy who can make a 100 mph plane out of it.

1. Thunder Tiger Champion 45
2. MDS engines
3. OS 91fx ( Owned 2) still an OS fan though
4. Kyosho products are way over priced for the quality you get. Better off going thorugh World Models.
5 . Morris Hobbies

"


Soooooo...you have never owned any of this stuff, but you know all about it? That's just remarkable.
Please substitute some other item for the FX91...I am only interested in hearing your expert opinions on things you have NOT actually owned, like the Kyosho Sabre and Gee Bee. I'm fascinated by your very quick and definitive review on the gee bee. It was underpowered? What engine was that?
Please also give your opinions on ALL of the OTHER ARF Gee Bees out there on the market.

thats a little mean .EasyTiger ,ain't it?

Yeah, maybe. I'll drop it. It just gets a little tiresome when somebody comes around looking for good information, and you get people just spreading rumors from the net. I tell you, you have to toss out fifty percent of what you read on these boards. Just the nature of the beast, I guess...