New project... Boredom is a curse... Lol

[Ole-Timer]

I located my esc on the lower wing surface and ram air into it. The air exits through a grill in the upper motor turtle deck.

Any place you need access in foamboard, cut the foam at a 45* angle on the sides and rear, make a cut on the inside of the foam at the front to create a hinge for the panel.

My tip washout is at least 1/2” to 5/8” , giving superb slow flight and super stable high speed flight. I have also used no dihedral at all, the wing is flat...!

Use a fish fillet knife to angle cut long tapered inside angles like the ones I use on aft spars at the glue joint.

use only the clear hot glue! The milky white stuff is low tack, clear is high strength. Don’t get greedy, I glue one joint at a time while forming the wing on the jig table.

A square trailing edge on the elevons has not cause flutter, at least not at 155mph...! I launch with a bungee cord and belly land in grass.

[Ole-Timer]

[rifleman_btx]

Man I wish I would have had your tips when I started on my first run. Now seeing all this I really see what I did wrong and where I need to go. Thank you so so much!

[Ole-Timer]

Wings indeed fly best with a fwd cg, I prefer 19-20% of mac as that locks the stability in with the tip washout. You will always need some up trim dialed in at slow speeds for takeoff and landing in this configuration.
If you endeavor to build from Elmer’s holographic foam board, available at Walmart... Beware that the holographic side is printed on a thin layer of aluminum that is conductive and can block signal to the Rx antenna. My gen 1 DX8 would suffer brownouts. My DX9 does not...

Happy building and your gonna love the speed...!

Bob

[rifleman_btx]

I'm thinking I'm gonna go with the blue foam with dollar tree foam board. Use my thicker blue foam for the leading edge and major framing, add wooden plates for the battery, electronics, and gear mounting and joining areas. Then sheet it over with the foam board. Final sealing will be done with glass. Power will be with .32 size motors, with 60 amp escs, on 4s 2700 batteries per side in parallel. I'll go for a 90" build. Should be pretty nice I'm hoping.

[rifleman_btx]

I'm gonna go with a 5° washout angle

[fhhuber]

I like to mix throttle to elevator for a wing. VERY SMALL down with increased throttle. Start at 1%. 5% almost never happens. The washout tends to push the nose up as speed increases.

[doctormike]

Yeah, EDF'f are no where near as fast as those propped wings! Doc

[rifleman_btx]

I hear ya, I have 4 wings I'm flying now, all one 79" the 900mm tech1, the cloud raptor, and my rmrc mako. However those all have vertical stabs so this project is my first one without stabs

[fhhuber]

For the same airframe at the same weight it requires appx 1.5X the watts for an EDF to give the same performance as a conventional prop.

Then the EDF is a heavier way to install the power system than the open prop.

This is why people accept appx 3 to 4 min EDF flight times vs the appx 8 to 12 min average for open prop. The only place to sacrifice to keep weight near the same is the battery.

[rifleman_btx]

Indeed, that's why I can't do edfs, until they can get the technology up to the point where we can have what I think of as acceptable flight times. I'm hoping they will get on the ball and finally produce the new batteries they showed in the model aviation mag. I think those would give the edfs nice 6-10 min flights I enjoy with my standard props. But I know they probably won't have those out for at least another few years

[Ole-Timer]

Having flown every type of electric model out there I’ve noticed they all share a common downfall. During amp draw tests, most do very well at the lower range of the throttle curve. It’s when the throttle is advanced above three quarter that amp draw skyrockets. Now there are models that may need that realm to operate in, normally when the model is underpowered or has induced drag issues. Consider your own experience and you’ll likely realize much of the time your flying is spent at half to three quarter throttle on a well designed airframe to power system. What I’m doing lately is creating a new throttle curve on some of my models to avoid the high amp draw at WOT. I fly the airplane and determine where the acceptable level should be set and trim back as required. It relieves excessive loads on your battery, esc, and motor that cause heat to build up which eats more power. Minutes can be added to flight time that way and your components are greatly relieved by it.
‘My latest case in point is a giant scale Pilates PC-6 Porter running a 12s system. A standard stock power curve produces a 127amp draw at WOT. I have reduced that to an 80% curve so the draw is now 85amp at WOT. A huge difference and the model does not normally need that kind of waste going on as I fly the wing and not the prop.

Bob

[OV10]

I remember the days of old were certain vehicle engine applications were not allowed to go above a predetermined RPM with the use of a governor.
A good approach to making an electronic governor.;)
I'd be curious as to how much in prop rpm you dropped for that 42A current drop on the "reset of WOT".
I personally wouldn't do this because I don't need to jam the stick all the way to the firewall and it would take away my ability to have the FULL power if needed.
An old school precision aerobatics pilot in the club I used to be with actually had a notched detent in his throttle stick at around the 60% range.
I used that same principle but did it electronically on the DX9 with an audible beep when I hit 70%.

[Boots Whirlygig]

Good stuff Ole-Timer and OV10. Throttle management. A DF Will never be as efficient as a propellor, but have improved significantly over the years. We accept the shortcomings and wait patiently for a Super battery so we don’t have to resort to a wet fuel to power our dreams. :Scared:
Maybe I shouldn’t use those two words in the same sentence.

[Kloverzero]

Maybe I shouldn’t use those two words in the same sentence.

LOLLOLLOLLOLLOLLOLLOL

[mr.frankenjet]

you do it for the cool factor :f16, the performance and fuel consumption improving all the time. Fulfilling the need for speed - Fly, recharge, repeat

[rifleman_btx]

Good times, and yes I have noticed the spike in amps over 75%. For some odd reason in my head I normally fly at 50-75% without even thinking about it. Only going wide open for show off passes or big loops and extended climbs. Other than that it's pretty much cruising at probably 60% or less. Also when at the upper limits you will see a major drop in voltage in your batteries when you hit those amp hungry wide open moments. Example here in my fpv osd footage from my 79" wing...

https://youtu.be/iAduoxlepk4

[mr.frankenjet]

true that, this is how I know I have the correct amount of power in a plane, it your forced to keep too high a throttle setting just to fly she is underpowered(hate that) .Nice to have that headroom for punching out and going ballistic but I don;t hold that for long.

[fhhuber]

I do a flight at WOT (and pretty high altitude) to set my timer. If I get 3 min to LVC @ WOT, that's my timer setting. Normal flying I vary the throttle a lot. When the timer goes off I have enough left to do at least one missed approach.

[Ole-Timer]

The majority of my fleet uses a straight up 100% throttle curve. I have a few birds, the Porter in particular, that are way over powered. In the end, it’s always about throttle management, what your flying, and the mood your in.

I did notice when I increased wingtip washout on the last flying wing I built, it would climb with increased throttle. I considered it more of a motor thrust line issue and increased the negative incidence in the motor. That resolved the tendency to climb at higher throttle settings. I also have an up elevon mix that’s switched on for takeoffs, slow flight, and landings. Off for 40mph n up.... and you can’t bust 150mph with a governor.