Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Whats a fast aerofoil for a DELTA

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Old 09-13-2004, 03:10 PM
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Ian.W
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Default Whats a fast aerofoil for a DELTA

Hi,

ive always wanted to try a fast plane, but the fear of wasting 100's on something i may get board on was a bit of a concern. So, after seeing an artical in a magazing on foam wing cutting, and having lots of spair servos, recivers and the sort lying around i thought id buy a chunk of foam, and how wire it (or CNC mill it if itll fit into the machine) to make a flying wing, like the whiplash or something of the sort.

However, i dont know my wing sections at all well, all i know is the NACA 0015 which is a 3D aerobatic section, not much use. Id like it to fly inverted quite well, as this is how i spend quite a bit of my flying time, i also want it to flyFAST.

Also, im thinking of buying a 2nd hand YS45 for it. will this be OK with a smaller, higher pitch prop??? if not ill have to revert to my old irvine 53

Thanks
Ian
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Old 09-13-2004, 04:08 PM
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Default RE: Whats a fast aerofoil

Interesting question, I've been wondering the same thing. I'm not so interested in building a flying wing, wanted something more realistic. Was hoping to build a jet like plane for one of the .25 or .15 engines I have on the shelf. Wanted something simple, kind of like the Lanier Shrike, but with a longer nose and tail section to make it look more like a real jet.
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Old 09-13-2004, 05:08 PM
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Default RE: Whats a fast aerofoil

Many of the fastest Quickee airplanes out there now are using either the Naca 66-012 or a similar foil. This is with a wing thickness of 1 3/16" and a chord of 9 3/4". Very Neutral airfoil that flies as well upside down, on knife, or right side up.

This airfoil performs best in the 160-170 mph range, but is still neutral at slower speeds.
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Old 09-14-2004, 11:36 AM
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Default RE: Whats a fast aerofoil

thanks Daven! ill give it a go

Ian
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Old 09-14-2004, 11:51 AM
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Default RE: Whats a fast aerofoil

heres a screen shot of something i got of profili 2

looks odd, aparently the P-51 tip aerofoil! this was the only one with the naca 66 012 in it.because i dont have the registered version, does it mean i dont have allt he aerofoils???

also, will the YS be ok?

Ian
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Old 09-14-2004, 01:29 PM
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Default RE: Whats a fast aerofoil

That looks good to me. Aim for a high point right around 50% and a C.G. about 30% behind the Leading edge.
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Old 09-14-2004, 02:17 PM
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Default RE: Whats a fast aerofoil

Hey Daven!

i thought a fast wing section would be thin? this loosk quite fat.

its a delta, so will it work liek it does on a quikee?

"root" chord is 35inch
tip is 10 inch not including ailerons on both of them

Ian
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Old 09-14-2004, 02:49 PM
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Default RE: Whats a fast aerofoil

In this class our wing must be 1 3/16" thick. You could thin it down a bit.
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Old 09-14-2004, 07:19 PM
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Default RE: Whats a fast aerofoil

Edible,

You can use Profili to thin a 66-012 airfoil down to for instance a 66-008...

The registered version of Profili has about 2500 different airfoils in it I believe... and you can even generate your own NACA's if that's not enough for you...

Registering Profili only costs 10 bucks... considering what you can do with that program, that is for free...
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Old 09-14-2004, 11:49 PM
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Default RE: Whats a fast aerofoil

you can generate NACA airfoils with the free version, or before I bought it I could, but I still recommend you buy it if you like it. While in "Airfoils management" click management---generate new NACA airfoil... pick "NACA series 6" and type 66-012 or 66-010 or whatever thickness you want in %.

Joel
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Old 09-15-2004, 09:25 AM
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Default RE: Whats a fast aerofoil

Daven - you suggest a cg at 30% behind the leading edge. Is this at the MAC or some other location? The reason I ask is this: my understanding from various sources is that 30% at the MAC may be unstable for a pure flying wing, i.e. no stabilizer. I've designed and built a number of flying wings, but never a delta, so I'm curious. Thanks.
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Old 09-15-2004, 10:13 AM
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Default RE: Whats a fast aerofoil

I missed that it was a delta wing. I'm not sure I would recommend this airfoil for a delta. I have only used it on a constant chord wing, never a Delta. I don't have any experience with Deltas so I am in no position to make any recommendations.

The 30% comment was for a constant chord wing, not a Delta.
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Old 09-15-2004, 10:43 AM
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Default RE: Whats a fast aerofoil

ah, so this isnt a good aerofoild for a delta??? must change the topic title.

what is a good delta aerofilo for a delta then??

reason ive chose a delta as its very simple to make, no fuz to build (within the true sence of a fuz).

im hopefulyl going to buy 100mm thick white foam for the wing, make 2 panels, but join em then glass the lot for the strength. YS45 possibly for power standard servos, nothing too fancy
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Old 09-15-2004, 10:49 AM
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Default RE: Whats a fast aerofoil for a DELTA

I'm not saying it wouldn't be a good airfoil for a delta, just that I have never used it for a delta... It may work just fine, I just don't know.
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Old 09-15-2004, 10:55 AM
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Default RE: Whats a fast aerofoil for a DELTA

thanks for the tip on the creating your own NACA sections Rudeboy!!!! its good fun typuing random numbers in and seeing how the section works think i may just buy this softwere

thanks again all for your time

ian[8D]
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Old 09-15-2004, 10:59 AM
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Default RE: Whats a fast aerofoil for a DELTA

i thinki ill give the 66-010 a try or the 66-008. they look nice and "fast". thanks again.....Ian[8D]
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Old 09-15-2004, 02:13 PM
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Default RE: Whats a fast aerofoil for a DELTA

The YS-45 is VERY strong but only with a full tuned pipe or UT muff. it is also fairly heavy compared to the field-

How big is the "wing" gonna be?
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Old 09-15-2004, 03:10 PM
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Default RE: Whats a fast aerofoil for a DELTA

Wing...............

40" span
35" "root" chord
10" tip chord
not incl. ailerons.

im a relative novice to designing. Please point me out to stuff/ tell me wot to do to make it fly.

IF its nose heavy, i can put the servos right at the rear, and the tank on the CG (YS got a pump) and put allot to the rear, will it work???

also, had a little go on a laser arrow on aerofly pro, found that i could change the section to NACA 66-012 and it was all over the plave, fast but didnt like to do elevatr and aileron maneuvers.

What pipe do you recomend with the YS? im may get it, depending on the price, as i havent found it out yet.

thanks everyone
Ian[8D]
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Old 09-15-2004, 04:18 PM
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Default RE: Whats a fast aerofoil for a DELTA

I don't claim to be an expert, but I have designed and flown a few flying wings, although none were deltas. If you want to experiment, the NACA 66 series could be entertaining, but if you want something that will definitely fly in a controllable fashion, I'd stick to the NACA 63 series or something similar. These airfoils are still low drag, if you build them accurately, but the high point is around 1/3 back from the leading edge. The NACA 63 series was used in the orange flying wing below (long departed). I used one of the symmetrical Eppler foils in the blue swept wing below (also long departed), but the Eppler foils are theoretically more draggy in straight and level flight. For my flying wing designs, I've located the cg in the range of 15 to 20% of the MAC (mean aerodynamic chord) and they have been stable and controllable. However, deltas may be a bit different. Perhaps someone with a Dust or Whiplash can chime in and offer some advice.
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Old 09-16-2004, 03:29 PM
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Default RE: Whats a fast aerofoil for a DELTA

thanks. ive selected my aerofoil now, 66-008. Im goign to buy Profili2 soon enough (possibly the Pro version) and then ill either CNC cut it, or i may even laser cut a few ribs then build a built up wing

thanks everyone
Ian[8D]
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Old 09-16-2004, 05:16 PM
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Default RE: Whats a fast aerofoil for a DELTA

This is not exact but this is how the ribs look on the Diamond Dust. It is a Delta wing plane and shaped looks similar to Whiplash. It flies very slow as well as very fast and inverted.
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Old 09-16-2004, 05:18 PM
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Default RE: Whats a fast aerofoil for a DELTA

I forgot to mention that is how the main center ribs and out ribs look like. the wingtip rib was pretty much a flat skinny piece by the time it tapered from center to wingtip.
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Old 09-16-2004, 10:00 PM
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Default RE: Whats a fast aerofoil for a DELTA

There's no need to get too scientific about it, the DIAMOND DUST "airfoil" works very well. Since there's only a couple of ribs on each wing panel, the covering sag makes up the bulk of what the actual airfoil shape is. Have seen several deltas and scimitars that supposedly had all the latest and greatest aerodynamics going for them, but they flew like crap [compared to a DD] because they were too heavy. The point to all this is I would place more emphasis on lightness and simplicity, and just keep the wing strong, thin, ripple free and light.
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Old 09-17-2004, 03:43 PM
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Default RE: Whats a fast aerofoil for a DELTA

so would you recomend a built up wing with only a few ribs or a foam wing?? both are easy for me as i have access to a CNC cutter and laser cutter so ribs are no problem

COBRA: thanks for the pic

ian[8D]
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Old 09-17-2004, 05:17 PM
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Default RE: Whats a fast aerofoil for a DELTA

If you are going to get real thin, either method will work with the help of carbon fiber kite rod . It is hard to improve on the DIAMOND DUST style of construction, the way it flies, lands and launches at 2.5 pounds is truly awesome. I think if you are handy with foam, either way will give good results, but don't get carried away with glassing the foam, or you will be building something that needs a launcher to get airborne, and lands with enough speed to be hard on the airframe.
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