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Old Dec 01, 2003, 02:57 AM
Dave?
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Quote:
Originally posted by DaveGherardini
So how are you going to rig that thing? Flying diamonds are a hand full but ha,,,thats the idea.... Elevons?, A/E? ele pusher i assume...well i just reread your posts and see its a/e, with pusher. Flat plate style wings,,,man this is different!!...It does have that YF23 look ...pretty cool.....
Large ailerons with flaperon mix and elevator. I have 2 camber settings plus nutral on the ailerons.

So far I can ger good ground speed but once the ground velocity is up I start pulling back slow and it pops straight up into a stall in the bat of an eye... I think the CG is too far forward, Dan says it's too far back, the Ex-Pres of the Harbor Soaring Society (ex-pres. and R/C flyer for 30 years, charter member of the oldest AMA sanctioned soaring club. I am also a member.) says I am right and I need to move the CG back... so tommorow I am going back 1 inch from today initial flight. I have seen somewhere a spreadsheet fo CG calc of varing sweeps and shapes, I will have to locate it again.

I can't wait to get the prototype setup, I have a Jeti 15/3 that wants a late model war bird airframe. 25oz static thrust 15oz in flight thrust and 77mph pitch speed. 3.5 minutes flight on CP1300... Prop 5.5x4.3. Weight of the power system 16oz, airframe weight 6oz (with now Rx or servos)... That should make my YF-23 almost respectable.
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Old Dec 01, 2003, 09:38 AM
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I think it was pilot error =P
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Old Dec 01, 2003, 10:44 AM
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If the model does an instant pop up with a little up elevator , your CG is definitely too far aft. Only that relationship can cuase that type of reaction. A model will stall when nose heavy, but it will never do a pop up like that.
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Old Dec 01, 2003, 07:36 PM
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excell

This might be it
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Old Dec 01, 2003, 07:42 PM
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Balancing those types are tuff though. Laterial balance has to be real close to but im sure your doin that. Theres nothing like the challange of getting an unusal design flyin strait and level. Its does seem from the pop up stall that the cg would be to far aft but sometimes i have found that dimonds do wierd things...Sounds like your getin close though...
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Old Dec 01, 2003, 08:14 PM
Dave?
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Well I took it out for lunch (It did not eat much) and moved the battries till I had the pack hanging "2" off the nose... so far that has given the best show but still not flight ready... but close...

I am going to cut and section the prop well and motor cut-out back in and move the motor forward enough to match the current CG with the battery backed up next to the motor. Then I'll move the battery forward one inch at a time and see what happens.

This has been about the most challenging plane I have attempted, so far it made the F-117 look like childs-play.

Thanks for the d/l Dave I will have a peek at it and make another attemp to calculate it, but if all else fails I can still ball back to the trial and error, I am getting close and moving in the right direction.
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Old Dec 01, 2003, 08:27 PM
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BUNNGEEEEEEEEEEEEEEEEEEEE
U Need more ground speed rich!!!!!!!!!!!!!!!
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Old Dec 01, 2003, 08:44 PM
Dave?
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Got plenty of speed, If I thought that was the problem I have that 15/3 77 mph, with that I don't need wings! Thrust of the power system exceeds its own weight by 11 oz.
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Old Dec 02, 2003, 12:10 AM
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Summer, If its flat it wont be a very stable high speed flyer. There in sets the speed envelope it can fly at. then you prop it for that speed envelope. its envelope is going to be real short and hard to find but hopefully obtainable. "wow" them to big of words for me... HEHEHEEE...
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Old Dec 02, 2003, 12:17 AM
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The tough thing is to build it with the most mass close to the AC. But that cant always be done so when you have to spread out the weight you would spread it out the least. And save weight. ..with an EDF you might be able to get it closer with that airframe.
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Old Dec 02, 2003, 04:31 AM
Dave?
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I was considering powering one up with the 020/powerfan from Wattage. this would let me use the enging ducting for battery enclosures. 2 5 cell packs.

Weight of the bare bones airframe (no wheels, electronics or power system is 6 oz. Looks like stall speed was under 20 mph judgeing by the actions I have seen so far. the only real question now is after I get the CG set will I be able to keep it stable. This will be the true test of my thumbs. I don't think it will be hard to manage.

I think it will be like my little 20 inch johnson powered wing that I had a hard time letting go of to develop the Le Pew... If I can get it in the air I can fly it.

I am cutting out proto #2 tonight, I will use #1 for a few more tests as it is getting beat up pretty good from landing hard on take-off attempts.

My final version I want a 40 inch span, I was considering laminating EPS foils and leading edges to the sturdyboard wings as well as a couple good stout carbon spars from tip to tip. It would not be hard to do and would probably improve overall flight I was thinking of doing the cockpit section in EPS to to give the plane some dimesion...
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Old Dec 06, 2003, 01:16 PM
Dave?
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Building #2 today, I will be moving the motor forward on this one and go for a CG of 7" to start Wing Chord nearly 21 inches at the root but only 1.1 inches at the tip.

Refined the profile look a bit more.

I am not ready to todd in the towel just yet... (I love pounding my head on rocks too!)

I will take it out round 3 or 4 pm today or early AM tommorow if I am not done.
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Old May 19, 2005, 09:39 PM
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Twin EDF55 YF-23

Letís revive this topic YF-23 Black Widow
Here is my 3D Twin EDF Foamy

Wing span: 23.75
Length: 37
Flight weight: 12.5oz
Fuel cell: GWS Ni-MH 750mAh 9.6v
EDF: 2x GWS55-150
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Old May 19, 2005, 09:49 PM
AMA 353531
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United States, CO, Colorado Springs
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I'm starting one as well, 20" on 2 cells and twin EDP-50. Targeting indoor flight.

For something a little different, I'm cambering the wings with a simplex airfoil, 6% at the root, transitioning to something less at the tip. The simplex will handle the extreme taper and transition nicely.
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Old May 19, 2005, 09:49 PM
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sexy
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