C-ARF Ultra Flash build Thread + Video
03-03-2017, 11:58 PM
#5628
NACA duct where primarily designed as air inlets and where oriented with the small aperture at the front, the floor of the duct was at a specific angle to allow the air to flow into the body in the most drag free way, to use these as an outlet they should be oriented in the opposite direction, this is assuming that the external air pressure is lower than the internal, which would be the case with a moving body providing the outlet is positioned to the rear of the largest cross sectional area of that body.
Mike
Mike
Last edited by BaldEagel; 03-04-2017 at 12:11 AM.
03-04-2017, 03:57 AM
#5630
Fair enough I thought they where there to take air out of the fuselage, having never used a bypass I am not aware of their use, but to be fully effective I think they still need to have a side wall and enclosed on the underside?
Mike
Mike
03-04-2017, 06:55 AM
#5632
Thread Starter
Mike
The way the bye pass is done, the cool air enters the outer cool wall behind the bell mouth, its cut short by 2"
The cut outs could be square, rectangular or anything as its the rear augmentation that sucks the heat out. The holes are just to allow air in. Yes, walls and floor might be better, but 50 degree temps and 11 years of the Flash have shown this set up to work...
The way the bye pass is done, the cool air enters the outer cool wall behind the bell mouth, its cut short by 2"
The cut outs could be square, rectangular or anything as its the rear augmentation that sucks the heat out. The holes are just to allow air in. Yes, walls and floor might be better, but 50 degree temps and 11 years of the Flash have shown this set up to work...
03-05-2017, 02:36 AM
#5634
Thread Starter
Nice work, but that channels the air back towards the tail, the stock pipe air inlet is forward so it will need to swirl around in the fuselage before it gets to the inlet. There is no need to cool the outer wall of the outer pipe. I'm sure the difference is not measurable though, so no real harm.
The process of pipe cooling is 99% air moving through the gap between the two tubes
The process of pipe cooling is 99% air moving through the gap between the two tubes
03-05-2017, 08:38 AM
#5635
Nice work, but that channels the air back towards the tail, the stock pipe air inlet is forward so it will need to swirl around in the fuselage before it gets to the inlet. There is no need to cool the outer wall of the outer pipe. I'm sure the difference is not measurable though, so no real harm.
The process of pipe cooling is 99% air moving through the gap between the two tubes
The process of pipe cooling is 99% air moving through the gap between the two tubes
03-05-2017, 09:52 AM
#5637
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Unless you like cruising around half throttle most of the time, you probably wouldn't be happy with main tank only. That would probably give you a four minute flight. Probably less.
03-05-2017, 10:29 AM
#5638
Thread Starter
Fuselage tank only is not practical. Fuselage and wing is common in the U.K. Flights are 7-9 minutes depending on turbine and throttle abuse
03-05-2017, 05:43 PM
#5641
I run fuse tank into wing tank into header. Wing tank has better geometry for a final tank and I don't like the idea of pulling fuel uphill as would be the case if you went wing to fuse to header.
03-05-2017, 06:49 PM
#5642
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I found these to do the NACA Duct What do you think ? http://www.peakaircraft.com/Products...n=D190&pID=304
Or do you think cutting it like this in the pict is good enough and save 30.00 Dollars
Or do you think cutting it like this in the pict is good enough and save 30.00 Dollars
03-05-2017, 07:05 PM
#5643
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I found these to do the NACA Duct What do you think ? http://www.peakaircraft.com/Products...n=D190&pID=304
Or do you think cutting it like this in the pict is good enough and save 30.00 Dollars
Or do you think cutting it like this in the pict is good enough and save 30.00 Dollars
.
03-05-2017, 07:49 PM
#5645
03-15-2017, 05:53 AM
#5648
Just finishing up my Blue Angels UF, Preliminary checks show that I'm really nose heavy. Is this typical? It's probably addressed somewhere in this thread but, it's so long, I can't find it. CGing at 225mm, gear up.
My only deviation from stock is a Tam's pipe, which is about 10oz lighter than the CARF pipe. Otherwise, my equipment layout is stock, engine is a Cheetah, Batts in the side pockets up front. I'm so nose heavy that I don't think I'll be able to balance by shifting equip. I'm likely going to have to add tail weight
Have never had to do that in a jet yet, they're always tail heavy!
Good news is the jet is only 22lbs!
Mike
My only deviation from stock is a Tam's pipe, which is about 10oz lighter than the CARF pipe. Otherwise, my equipment layout is stock, engine is a Cheetah, Batts in the side pockets up front. I'm so nose heavy that I don't think I'll be able to balance by shifting equip. I'm likely going to have to add tail weight
Have never had to do that in a jet yet, they're always tail heavy!Good news is the jet is only 22lbs!
Mike
Last edited by luv2flyrc; 03-15-2017 at 05:56 AM.