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Old Apr 10, 2003, 04:38 AM
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rycb77's Avatar
San Jose, CA
Joined Apr 2003
13 Posts
F-86... crash and burn...

Took up my fresh F-86 today., I think maybe the winds might have been moderate, probably about 6-8mph. I hand tossed into the wind took off great went even further and higher than I wanted it to for a first flight. As soon as I attempted a 10-15 degree bank to the right out of the beloved wind it went into a dive and tried to see where the ground hogs live.

Here is my setup:
RTF 19.4 ounces
Electron 6 receiver
Cirrus 6.2 servos
Aileron throws 3/16"
Elevator approx 1/8"
Wattage IC-380AS 30amp esc
HeCell 10 cell 1100mah Nimh
CG balanced, rebalanced, then balanced again 3 1/8"

The only thing I could come up with is that because of the light to moderate winds once I turned downwind I did not have enough air going to the fan. Also probably the tailwind did not help either. I have been reading post for some time now and I have heard a few suggestions to fix but I have also heard of people flying stock just fine. Any clues?
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Old Apr 10, 2003, 04:54 AM
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Phillybaby's Avatar
Cornwall UK
Joined Aug 2002
2,565 Posts
6-8 is fine, when mine turns downwind it kinda slides and looses a little heigh, but its not stock set up control wise, when you turned you gave up elevator, which rasies the ailerons and lost you lift, the stock set up really is the wrong way around, how it'd fly the other way i dont know.
IF you have a plane left to fly, dont give up trim to keep it flying level, let the speed build up and it'll stop sinking, this isnt an easy thing to do after you take off and have to do a turn to go downwind.
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Old Apr 10, 2003, 05:25 AM
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San Jose, CA
Joined Apr 2003
13 Posts
hmmm...

Yea i guess it might be a rock and a hard place situation with the stock controls. The more of a dive you go into the more elevator/aileron you need to apply to pull out losing even more lift. I do not however have any kind of up trim at all.

But when i turned out of the wind it went down like a rock. Which was very strange to see. It was flying into the wind for aprox 7-10 seconds when I made the turn. I was climbing for most of that time, which might have been my problem as I would have turned at maybe a lower speed than desired.

Battle damage not that great definately repairable... I do not know what will happen when i try to attach a pic of it but well see.
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Old Apr 10, 2003, 05:40 AM
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Phillybaby's Avatar
Cornwall UK
Joined Aug 2002
2,565 Posts
first you need a spar in that wing. i do climb on my climb out, but i also level off and gain some speed before my turn which is maybe, erm... house height, 30' ish, i then trim on the downwind diving and gaining speed till im at full flying speed
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Old Apr 10, 2003, 06:05 AM
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San Jose, CA
Joined Apr 2003
13 Posts
Quote:
Originally posted by Phillybaby
first you need a spar in that wing. i do climb on my climb out, but i also level off and gain some speed before my turn which is maybe, erm... house height, 30' ish, i then trim on the downwind diving and gaining speed till im at full flying speed
Yes I agree. I was thinking of doing 2 mods. One is the wing spar (CF arrow shaft) and the other is the cheater hole mod with scoop. That should help with what I think in addition to me just not knowing the handling characteristics is a MAJOR airflow problem. I think also if you turn downwind and you put all the control surfaces up they can easily act as a downward force if there is enough wind. This is definately a light to moderate air aircraft.

I am anxious almost to go out and swap motors and go for the Mega16/15/3. I am however going to resist that temptation until I can get the stock ver flying correctly.

Parts are on the way from hobbypeople. You know where the cheapest place is to buy a new one is? Nesail has it for $94.99... That was the cheapest I have found...

Thanks for all your help Philly.
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Old Apr 10, 2003, 07:55 AM
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Phillybaby's Avatar
Cornwall UK
Joined Aug 2002
2,565 Posts
94.99 for a new Sabre? noo.... cant be, there 69ish over here so thats probabley $69ish for you.
theres a great Sabre mods page on here, Wattage Sabre wont fly its called. theres also lots of infomation on my website www.philsrcworld.fsnet.co.uk
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Old Apr 10, 2003, 12:39 PM
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Ed Waldrep's Avatar
Las Vegas, NV
Joined Dec 1996
7,937 Posts
The Wattage Sabre will tip stall. The wing will drop right out from under you if you get too slow, it happened to me on the first flight. I was flying a brushless setup but not enough cells, I didn't check first, was only pulling 120 watts instead of the 180 I though I had. I was at the top of a 6 foot hill, I kinda girly tossed it, didn't run first, and it settled to the ground fast. I pulled up but not really hard, just trying to stay airborne. It tipstalled to the left and rolled itself into a ball, breaking off both wings.

Washout would probably fix the problem, but there is none. You can't twist washout into it, it's a foam wing. it's the same foam wing as the one that is on the Wattage Hawk, so it's not optimised. I might someday cut some foam cores with different airfoils and some washout as I make my first fuse into a plug for fiberglass parts and made a mold, but that project still sits, plus I have one of the K&A mini Sabres the same size.

After my first flight I added NASA dropped leading edges to the wingtips. I made them from balsa and they stuck out about 3/8 inch. I never really got to test them, on the next flight I successfully launched and on the first circuit I pulled a loop and the wings came off in-flight. I hadn't added a spar and with the extra power the foam failed at the wing/fuslelage joint. I should have known better. I can say that in the loop on the way down I didn't tipstall. The drooped leading edges are being used on full size aircraft like the Sirus SR22 and they work. I'm not saying the Wattage Sabre needs them but I think they help, I just wish I had got the chance to know for sure. If you keep the plane out of the low speed portion of the flight envelope and not stall it you may not have any problems, but you'll be close to that area a lot in the stock setup!

I also make the seperate elevator pushrod mod, and it was fairly easy. I used the rods that go from the aileron to elevator and just spliced them at one end to make a Y that went to both elevator halves. There's info on the zone on how it's done. My elevator servo was in the cockpit in the rear. My brushless controller was sitting on the side of the fuse in a recess in the foam I created by the cheater hole, so all I had in the cockpit was the receiver and the servo.
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Old Apr 10, 2003, 12:50 PM
AKA Cactus
Phillybaby's Avatar
Cornwall UK
Joined Aug 2002
2,565 Posts
The stock setup also causes tip stall, as does not being carefull with wing alignment when you glue them on.
i dont have either problem and i've tried to stall it, but it didnt want to, just fell fast and level. I can slow it right down for landing and pull up hard with no roll out.
Wattage really need to include a spar, and make wing alingment easier
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Old Apr 10, 2003, 03:23 PM
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rycb77's Avatar
San Jose, CA
Joined Apr 2003
13 Posts
interesting posts...

Yea that is true tip stall would be bad thing with this aircraft you would not notice it until the last possible second and by that time it would be too late.

Also with that going on there is also POOR stall recovery and as soon as you get into a dive you are done. In my case I must have been approx 100' high when I started into my dive and could not pull it out. I only managed to keep it from going straight into the ground and hit at a slight angle to minimize damage. I was also flying in a tall grass field which also saved me some considerable damage.

The Cirrus SR22 wing design is an interesting one. I noticed that a while back when I was at the field. The leading edge is stepped as it gets further down the wing towards the tip and drops down a bit. Definately would help in isolating the stall towards the fuselage.

Philly i like your site, good sabre review. Where did you say I could purchase the sabre for cheap?
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Old Apr 10, 2003, 03:39 PM
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Herb's Avatar
Irvine, Calif USA
Joined Feb 1999
12,177 Posts
The wattage sabre flies *much* better (even with the stock s400 setup) with a separate elevator servo, ie without the suggested abominable ail-to-ele linkage setup which further aggravates the nasty tipstalling tendency of a zero-washout wing profile, as discussed in this thread from last summer :

http://www.rcgroups.com/forums/showt...5&pagenumber=3
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Old Apr 10, 2003, 04:23 PM
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rycb77's Avatar
San Jose, CA
Joined Apr 2003
13 Posts
Quote:
Originally posted by Herb
The wattage sabre flies *much* better (even with the stock s400 setup) with a separate elevator servo, ie without the suggested abominable ail-to-ele linkage setup which further aggravates the nasty tipstalling tendency of a zero-washout wing profile, as discussed in this thread from last summer :

http://www.rcgroups.com/forums/showt...5&pagenumber=3
Yes I have read that post, you seem to be very experienced with this aircraft. Nice sabre by the way, still flying it? I do believe I should do the elevator servo mod on my new sabre. What is the consensus on the best technique? Server in the cockpit, behind the cockpit on top of the fuse, or somewhere else?

Also personally I believe this plane just needs more power. It would help you avoid bad spots such as the one I got into yesterday.
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Old Apr 10, 2003, 04:38 PM
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Phillybaby's Avatar
Cornwall UK
Joined Aug 2002
2,565 Posts
My servo wasnt the easiest to install, but i dodnt want the servo sticking out the top of the plane.
The sabre is currently 62.99 in Slough Radio Control Models and they have world wide order service, however i'd say its probably cheaper that side of the pond.
if not, the number is ( uk ) 01753 522222
Thnaks for the site comments, have you seen the test flight video? did the first turn look anything like yours? triming was a bit hard coz one servo is aileron, one is rudder and then mixed, so they have seperate trim, however i normally just do the aileron ( still no tip stall )
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Old Apr 10, 2003, 05:29 PM
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rycb77's Avatar
San Jose, CA
Joined Apr 2003
13 Posts
Yea I do not know yet which method of elev servo i am going to do, but i think everyone agrees including me now that it is needed. I have found now the sabre for $89.99 over here, but so far that is the cheapest.

I saw the video, you made a lot more gradual turns. My turn to the right was a lot more sudden as it had to be cause it was heading for some trees (very fast). But still i felt that it should have been able to handle it and should have been up to speed by then. However we know the result.

My new sabre will have the following:
elevator servo
cheater hole mod
arrow wing spar
Mega 16/15/3 (might as well)

This sabre I am going to patch it up and use it as a guiney pig for more flight data. It would be nice if they sold this bird without the motor for cheaper



Quote:
Originally posted by Phillybaby
My servo wasnt the easiest to install, but i dodnt want the servo sticking out the top of the plane.
The sabre is currently 62.99 in Slough Radio Control Models and they have world wide order service, however i'd say its probably cheaper that side of the pond.
if not, the number is ( uk ) 01753 522222
Thnaks for the site comments, have you seen the test flight video? did the first turn look anything like yours? triming was a bit hard coz one servo is aileron, one is rudder and then mixed, so they have seperate trim, however i normally just do the aileron ( still no tip stall )
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Old Apr 10, 2003, 05:38 PM
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Herb's Avatar
Irvine, Calif USA
Joined Feb 1999
12,177 Posts
Quote:
Originally posted by rycb77
... I believe this plane just needs more power...
More power is a good thing, but the included stock setup works ok, it does fly decently once you set it up. Both Bruce, Doug, Jason, Phil and myself flew the F-86 at our field for a while with the stock setup and the elevator servo modification. They all flew ok.

To avoid tipstall with your setup you should perhaps try to reduce aileron throw.

Flying side by side we could compare , the poor ducting means some but not a whole lot of improvement when going brushless ...
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Old Apr 10, 2003, 06:02 PM
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rycb77's Avatar
San Jose, CA
Joined Apr 2003
13 Posts
That is a amazing looking aircraft. I love the paint scheme, the chrome tape is a nice touch.

I think your approach for putting in the elev servo is probably the best and avoids potentially problematic Y jobs. Is that tape the only thing holding the servo in from falling into the fuse?

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