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Old Oct 30, 2012, 11:02 PM
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A 2W-30 in a nicely balanced CS10 fan on 8S should give you 2.8-2.9kg thrust and over 2000watts. Just watch your amps and make sure you have enough cooling.

It might be enough for 175mph or more in something like this:

http://www.hobbyking.com/hobbyking/s...dProduct=15533
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Old Oct 30, 2012, 11:19 PM
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you need to talk to Lee Liddle. he makes all kinds of Frankenstein fans, rewired motors and combos to go fast. he'll make your plane go over 200 MPH. go watch the Phase3 F-16 on youtube going over 300 MPH. it's quite the thing to see.

Rich
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Old Oct 31, 2012, 12:02 AM
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It's not one of those things where a GPS spat out a 300 one time, and that's the plane's speed, is it??
Sorry, just seen a bunch too many of those.

300 on a P3 F16, eh? I'll peruse Youtube and pull out the doppler.

I have been referencing Lee's powerful 70mm fan thread, and it's got my wheels turning.
I like the idea of hacking down the CS 90mm, as long as it can take the power.
I'm up for cutting anything down. Haoye rotor like Lee, or the CS like Frank, or any other 90mm rotor with solid construction.

I do also have a good alloy 70mm, if I could get the 5mm adapter I want to run the most powerful 28mm motor on earth
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Old Oct 31, 2012, 12:31 AM
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United States, CA, Santa Clarita
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I believe Tailslide 5.0 @ 177mph and myself @173, still hold the fastest (official) speeds with a Phase 3 F-16.
These were "live, in person" upwind passes in one direction only and radared on film and video at the same location, a few minutes apart.
I haven't looked on youtube for a faster one. (only these threads) Maybe there is.

I have some MEGA 16/45/1 (2780kv) motors with 4mm and 5mm shafts on the way.
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Old Oct 31, 2012, 03:29 AM
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United Kingdom, England, Cobham
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Quote:
Originally Posted by Fanflyer View Post
I got 162mph out of a 70mm clipped wing Sniper. ARC 28-48-1, Wemo MiniPro, 65C 4S. That airframe won't carry more than 600 grams of battery and still maintain CG without adding weight in the tail.
I got around the Sniper CG problems by using 6S 2600mAh, made up of 3 x 2S packs: 2 packs as saddles either side of the fan and the third in the normal canopy area. Goes like snot on 1400W, but some say the Sniper speed is limited by the intake size.

Jacques
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Old Oct 31, 2012, 03:45 AM
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spears are already very heavy. Mine had an overbuilt fuse, way to much resin IMHO.

My super sniper did 155mph off 1400 watts. Technically it would take +3300 watts for the same airframe to hit 200mph. I had the the composite super sniper with the fully molded wing (I.E. it wasn't going to fold).

HET Super Sniper with ARC 28-47-1 (2 min 20 sec)


With some aerodynamic tweaks (no servos sticking out on the wings, smoother intakes, etc etc), and the right power system, I think 200mph with a sniper is possible.

I've run a few 70MM's to +3000watts. Only DS-30's will take that abuse, and even then sometimes they won't. I spun the center right out of a DS-30, with one of my 12S setups.

The butter zone is right around 1900-2100KV, for 10S-12S. About 80-90 amps depending on load. I used 3S 2100 40C batts. These days you can get 55-65C batts no problem.

The only motors I got up to 3KW with any kind of reliability were the HET 2W-30 (only in very short bursts, on 11S), a Neu 1115/1.5Y(12S), and a Mega 16/40/1.5R(10-11S depending on batteries).

Those all spin the DS-30 to around 75K RPM. Trust me, it's a hell of a noise.
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Old Oct 31, 2012, 08:00 AM
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Pete, where'd the composite wing 70mm Sniper come from?
That's one airframe I've been looking at, but I've also heard about the intakes being too large, and I saw one last week at the LHS and they do look pretty "parachutey".

If I got a composite wing version, I'd like to try pinching the intakes down. Think it'd be better to extend the intake forward and fair it in to a smaller hole? Or cut it back and take chunks out of the glass to tighten it up?

75K RPM on that DS-30 fan is ridiculous! That's why I'm looking to use a higher draw fan, to keep the watts up but RPM down.
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Old Oct 31, 2012, 08:06 AM
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Quote:
Originally Posted by efflux RC View Post
I believe Tailslide 5.0 @ 177mph and myself @173, still hold the fastest (official) speeds with a Phase 3 F-16.
These were "live, in person" upwind passes in one direction only and radared on film and video at the same location, a few minutes apart.
I haven't looked on youtube for a faster one. (only these threads) Maybe there is.

I have some MEGA 16/45/1 (2780kv) motors with 4mm and 5mm shafts on the way.
Those are more realistic speeds
I like when people take the effort and decency to post what the plane can actually do when it's not pushed by a 30kt. wind!

Great to hear about the 16/45/1 motors becoming available.
These give the opportunity to run the high power without being on the edge.
...or maybe ULTRA high power and still be on the edge!

Gary, what do you think would be the best use for the 5mm shaft motor? That's what I've got and I would LOVE to run it in the Mach alloy fan.
Any chance there could be a 5mm shaft adapter for the fan?
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Old Oct 31, 2012, 09:30 AM
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I have a feeling there have been some fudged numbers in here.

I do believe you can break 200, but not with what some people have suggested.

I personally don't believe you should do any CS fan... The problem is they don't hold up to the high RPMs. They are also more of a high thrust fan, however the actually efflux speed is lower than say a 5 blade spinning st the same power set ups.

The spear is a clean airframe but I don't believe that "cleaned up" spear truely hit 200.... Yes getting rid of the vertical is big, but he also add 2 winglets just as large! Truthfully it would be more efficient cutting down the main vertical, and adding small woinglet to improve tip efficiency.

I agree that a composite super sniper could be fast.

I also feel that all these jets could still be too draggy. There is a reason F5d airframes are the way they are.

You are going to hate this.... But an airframe in the style of that foam Zephyr would truthfully have the MOST potential. It sounds horrible I know. But if you were to take a zephyr, shave down the airfoil a bit thinner at more of the mh30 or other F5d airfoils. Then of course glass, or cover in carbon the entire wing and fuselage. After the fuselage is glasses you can carve out all that useless foam in the most to fit larger power systems. This I'd also a shorter nose, to help with those CG problems.

Just my opinions Here....
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Old Oct 31, 2012, 09:45 AM
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I do think you make some good points on efficient aiframe type for speed.
The fastest wing for the least power is one with high aspect ratio and little sweep.That's how the pylons and hotliners get their efficiency.
However, an F5D or hotliner airfoil like MH43 is not the best for pure straight line speed, though.
Speed ships use a symmetrical or very nearly symmetrical foil since you don't need a very high lift/airspeed ratio when going 200mph. Look at all the F3S airfoils like MH54 and you'll see they're very symmetrical.

That brings the design of the plane to something like Claus's Slingjet that Frank flew his cut CS fan on.

I'm not opposed to running a pod-mounted fan, as long as I know it's efficient.

A 70mm CS fan sure wouldn't take 60K RPM. But do we know that a well-cut and balanced 90mm hub and blades wouldn't take it?
Cutting down the blades would add more pitch to them, so that would help out the efflux speed. I think. Right?
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Old Oct 31, 2012, 09:59 AM
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Oops forgot about the HET 1W-40

You dont get more extreme with a 28mm
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Old Oct 31, 2012, 10:46 AM
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200 mph on 4s is difficult if not impossible . My PHase 3 registered 159MPH with and ARC 28-48-1 on the HET blade , but my battery did not enjoy the ride.I also have tried the Nitroplanes Airfield A4 bored out to 70mm and reinforced with the HET 1W30 , I am now up to a 200 AMP ESC with a 2700 MHA 65/130 C battery , flight time is less than 1:45 , but it is a rocket. I think the trick is to keep the entire airframe as light as possible , but without strength bad things start to happen past 120 MPH.
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Old Oct 31, 2012, 10:59 AM
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Sorry Rocket boy, weight has little to do with speed. We need to look at aerodynamics, followed by power. At 200 mph it doesn't matter much about weight, it will pretty much fly wings or not. Its landing and taking off where you run into problems with weight....

Mudrnunoc;
I agree the most aerodynamic airfoil is generally symetrical, as the by product of lift is drag. You should check out Laminar flow airfoils such as the NLF0414 used in full scale. very interesting stuff...

I simply was suggest the MH30 or 43 because this would probably be the EASIEST to shave the Zephyr wing down to if that makes sense....If you glass it (or carbon fiber), reinforce the wing, do some minor airfoil/wing reshaping and cut out the foam in the fuselage/pod area after glassing, you should have plenty of room for power, and the aerodynamics to push it. Heck you could even redo the entir forward fuselage to be cleaner. The added weight of the composite covered tail will even help with balancing when you have heavy power system up front!

I agree with the CS90 Idea, it will definitely be more pitch. Downfall, thicker root on the blades, thicker blades, heavier rotor, and it still might not be strong enough... But only testing could tell.

Keep in mind with 3kw in a 70mm EDF and the goal of speed an exhaust of about 70-73% FSA will be faster then the common 80%. We aren't concerned with thrut, but more so Efflux speed, and volume. At 200 mph venturing into reduce inlet area can help as well. Essentially reducing inlet area down to 90% or so allows for a lower pressure zone inside the inlet, it also allows a slightly higher RPM in the Fan itself. The vaccum created will be more than enough and it shouldn't starve the fan at all.

Once again, these are just my (slightly) educated opinions.
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Old Oct 31, 2012, 12:21 PM
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Quote:
Originally Posted by nighthawk0077 View Post
Oops forgot about the HET 1W-40

You dont get more extreme with a 28mm
Unless you go with a more powerful and more efficient motor
Look up a few posts regarding the Mega 16/45/1 motors.
2780kv and good for over 4kW. No 28mm HET will touch that.
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Old Oct 31, 2012, 02:08 PM
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United States, FL, Mt Dora
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Quote:
Originally Posted by Rocketboy1030 View Post
200 mph on 4s is difficult if not impossible . My PHase 3 registered 159MPH with and ARC 28-48-1 on the HET blade , but my battery did not enjoy the ride.I also have tried the Nitroplanes Airfield A4 bored out to 70mm and reinforced with the HET 1W30 , I am now up to a 200 AMP ESC with a 2700 MHA 65/130 C battery , flight time is less than 1:45 , but it is a rocket. I think the trick is to keep the entire airframe as light as possible , but without strength bad things start to happen past 120 MPH.
i was able to reach 170 range on 4s. hot hot hot which i did with a Mega. but not sure what frame is needed for 200

as for obtaining the most efficient efflux. you cant really use the famous ball park 80%. not for speed. it'll have to be played with on the bench and will be depend largely on the intake efficiency. once you find the sweet spot on the bench, then back it off another 1-2mm for inflight efflux to increase. on teh bird i used, i was at 53mm

wemo or shuby will do it best on top end
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Last edited by stoneenforcer; Oct 31, 2012 at 02:54 PM.
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