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Aug 10, 2018, 12:44 PM
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hawaiianspork226's Avatar
Quote:
Originally Posted by Ron van Sommeren
Why 3-blade and not more efficent 2-blade props David? Ground clearance? Sound?

Prettig weekend Ron
for the looks mostly. i think ill buy a set of APC 12 x 12 props too if i need more top end speed...

if i fly this thing "scale", it wont look very fast at least as far as RC airplanes go - so the slower 12 x 8 3 bladers would be fine... but if it looks too slow, ill prop up to 12 x 12

-david
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Aug 10, 2018, 12:45 PM
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hawaiianspork226's Avatar
Quote:
Originally Posted by RobMason
Nice David - looking forward to the test flights

Rob
test flights will definitely be interesting. i anticipate there being some pretty weird demons hiding in its flight characteristics...

-david
Aug 12, 2018, 02:56 AM
Registered User
BenVK's Avatar
Cool project!!
You're very fortunate to have a CNC machine at work that can cut foam. What does your boss say about you using it to make planes? lol

Word of advice about your plane. You might want to re-design the motor nacelles so they don't hang so low under the wing.
I recently tried props on a Dynam Me262 instead of the EDF's to achieve longer flight times. It wasn't a success because of the very low thrust angle which caused all manor of weird and dangerous flight characteristics.

I know that the 262 is a low wing design and yours is a high wing but I would still try and get the motors mounted more in line with the wing if you can.

Bit like this.
Aug 12, 2018, 09:45 PM
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hawaiianspork226's Avatar
Quote:
Originally Posted by BenVK
Cool project!!
You're very fortunate to have a CNC machine at work that can cut foam. What does your boss say about you using it to make planes? lol

Word of advice about your plane. You might want to re-design the motor nacelles so they don't hang so low under the wing.
I recently tried props on a Dynam Me262 instead of the EDF's to achieve longer flight times. It wasn't a success because of the very low thrust angle which caused all manor of weird and dangerous flight characteristics.

I know that the 262 is a low wing design and yours is a high wing but I would still try and get the motors mounted more in line with the wing if you can.

Bit like this.
I did agonize about this quite a bit. At this point the project is far enough along to where I don't want to change course on it.

BUT - there would be other benefits to a nacelle redesign. The main landing gear is a bit of a challenge with such large tires. If I made the main wheels 4 or 5" instead of 6" then maybe I could bring the thrustline up closer to the wing airfoil centerline...

Yea I'll think on it a bit

Thanks

-david
Aug 13, 2018, 01:05 AM
Registered User
hawaiianspork226's Avatar
Quote:
Originally Posted by BenVK
Cool project!!
You're very fortunate to have a CNC machine at work that can cut foam. What does your boss say about you using it to make planes? lol

Word of advice about your plane. You might want to re-design the motor nacelles so they don't hang so low under the wing.
I recently tried props on a Dynam Me262 instead of the EDF's to achieve longer flight times. It wasn't a success because of the very low thrust angle which caused all manor of weird and dangerous flight characteristics.

I know that the 262 is a low wing design and yours is a high wing but I would still try and get the motors mounted more in line with the wing if you can.

Bit like this.
I took a look at the side profile of the plane again. I did try and place the thrustline approximately where the center of drag would be. Between the fat draggy fuselage and the wing, and the stab, I think the thrustline might still be in the right spot... What I don't know is where that center of drag will be through the flight speed envelope... Like does the WING drag increase more than the fuselage drag for a given airspeed change? I'm not an aero guy... I get the fundamentals of airframe arrangements but those more complex details... Well I ask for help with those usually lol

Still pondering

Oh and the cnc router is a very nice resource to have. As long as it doesn't interfere with production, and it doesn't get abused, it's up for grabs. The hardest part is finding time for design and programming honestly

-david
Last edited by hawaiianspork226; Aug 13, 2018 at 01:28 PM. Reason: switched fuselage for WING
Aug 13, 2018, 07:51 AM
Plane Nuts
RobMason's Avatar
Looks good to me David. You might get a nose down moment from the front sloped fuselage/canopy design, but it might be offset by the lift generated from the curve of the canopy. Thrust line looks to go near or through projected CD and CG

It "looks" right.

Rob
Aug 13, 2018, 01:18 PM
Registered User
hawaiianspork226's Avatar
Quote:
Originally Posted by RobMason
Looks good to me David. You might get a nose down moment from the front sloped fuselage/canopy design, but it might be offset by the lift generated from the curve of the canopy. Thrust line looks to go near or through projected CD and CG

It "looks" right.

Rob
lol yay

gotta love TLAR engineering... hehehe

-david
Aug 13, 2018, 07:37 PM
Plane Nuts
RobMason's Avatar
Lol
Aug 16, 2018, 12:33 AM
Registered User
hawaiianspork226's Avatar
Little bit at a time

Got the canopy glassed today. Did some more sanding on the fuselage

-david
Aug 17, 2018, 12:57 AM
Registered User
hawaiianspork226's Avatar
110KG HUGE RC TURBINE MODEL ALPHA JET AMAZING PERFORMANCE (11 min 3 sec)


Pretty cool. Similar layout. Huge awesome jet

-david
Aug 17, 2018, 10:54 AM
Plane Nuts
RobMason's Avatar
Easy way to guarantee it will fly stable - Gyro.

A friend uses the Aura 8 from Flex innovations, but the cheap $35 ones Motion RC sells are fine too.

That Alpha Jet was definitely gyro'd up - watch the elevator twitch on the approach to landing.
Aug 19, 2018, 03:00 AM
Registered User
hawaiianspork226's Avatar
Glassing...

4oz plain weave over fuselage and wing surfaces. Got left fuselage half done today

-david
Aug 19, 2018, 04:43 PM
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hawaiianspork226's Avatar
Got the other half of the fuselage glassed today. Super hot in the shop today. Was hard to not sweat on the plane lol but I didn't. At least I don't think I did

-david
Aug 21, 2018, 12:40 AM
Registered User
hawaiianspork226's Avatar
Got some sanding done tonight cleaning up the laps of the fiberglass getting it ready for the next areas to get glassed. Probably will do bottom surfaces next:
Nose wheel well, Bombay, bottom of wing, bottom of stab

Then the top surfaces

Feels good finally making progress

-david
Aug 23, 2018, 12:11 PM
RC Aircraft Junkie
jlk69's Avatar
Looks good. Won't be too long if you keep up this pace.


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