Anybody else scratch building tonight?

GliderFlyer

Elite member
This is my first model covered in doculam. There are many wrinkles, but none that bother me too much.
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Question:
Could anyone tell me how I can disable AS3X on the UMX radian receiver?
 

Brian B

Elite member
That's nice. Did you see the one called "Seahorse"?

Don McGovern was quite the prolific designer. Always liked his stuff. I got an old Jetco Navigator kit in the closet waiting to get built.

In the meantime, on what I'm building tonight, I think I'm finally ready for the maiden with my "Sora". Inspired by an un-named dream plane in Studio Ghibli's "The Wind Rises", which was based on the life of the A6M2 Zero's designer. Great Movie. Uses a Radial C-pack, with SRXL2 and Aura5 flight controller. All DTFB, taped, with a few 3D printed parts.
 

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Ratcheeroo

Legendary member
Hey I can't get over that airfoil - I'll be planning on copying that one of these days!
Absolutely! So here is where it gets interesting I think, I have these motors from a quad I used to have but not sure how to go about utilizing them for this project. Any insight , opinion on this would be greatly appreciated
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quorneng

Master member
Made a start on the Sea Hawk fuselage centre section "half shell" built over the plan.
FuseCentre1.JPG

There is no distinction between the green and grey foam other than it highlights the formers from the skin!
Once sufficient of the skin was planked for rigidity it could be lifted from the plan and the former cut outs 'adjusted' to allow the complete duct assembly to be inserted exactly half way in!
DuctInsert1.JPG

Now to add the other half of the formers and do some more planking.
 

leaded50

Legendary member
Made a start on the Sea Hawk fuselage centre section "half shell" built over the plan.
duct assembly to be inserted exactly half way in!
View attachment 203876
Now to add the other half of the formers and do some more planking.

You dont have any posibillity to mount the EDF more to rear? That way you could maked better intake direction on the airintakes. Thats reason for you loosing close to 50% of effect... or more. You will not gain much by a "ram-air" effect here either.
 

Brian B

Elite member
skymaster
My favoured construction method for a fuselage in sheet foam is by planking to create a half shell monocoque.
In this case (the fuselage for a Cessna Skymaster!) the 'half' formers are positioned over the plan and the planking (in this case 3 mm Depron) was gradually completed.
View attachment 203804
Once the half shell is complete it is rigid enough to be lifted from the plan and the other side of the formers added.
View attachment 203802
This is then planked to eventually give a complete fuselage.
View attachment 203805
The fuselage has no internal structure other than somewhere to put the battery & electrics relying entirely on the skin for strength and rigidity.
Not the easiest thing to do (the more you do the better you get at it) but it does result in about the lightest possible structure. Note most of the planks run the full length of the fuselage so the glue joints are not in tension where glue tends to be weakest.
The completed Cessna.
View attachment 203807
Everything is 3 mm Depron. The only balsa is in the wing spar and the short wing struts. Light so easy to hand launch and it belly lands just as well.
I intend to use the same sort of construction for the Sea Hawk but using 5 mm XPS foam sheet.

Nice construction technique. With all the rolling cones being done with MS, haven't thought much on planking. Great stuff here.
 

TheFlyingBrit

Legendary member
I've not really building as such, my 8" folding props arrived today from Banggood so I fitted a pair on my Vulcan, now I can finally maiden it.
It always makes me nervous hand launching a rear prop mounted plane. The folding prop option gives me a little more confidence, that I can get it out of my hand before I initiate the motor.
If the thrust turns out to be insufficient with the folding prop, I can always revert back to a fixed prop option with a catapult launch system instead.
 

Scotto

Elite member
Absolutely! So here is where it gets interesting I think, I have these motors from a quad I used to have but not sure how to go about utilizing them for this project. Any insight , opinion on this would be greatly appreciated View attachment 203874
Ive got some brushed motors id like to use too. This esc is kinda big but it could probly run 2 motors at once and you could double it and have all 4 motors from the quad on your wing for differential thrust.:p Other than that just about everything brushed seems to be incorporated into reciever unit.
https://www.backcountryrc.com/product-page/5ch-micro-servo-esc-brick
Maybe someone who understands transistors could help me.
 

Ratcheeroo

Legendary member

quorneng

Master member
You dont have any posibillity to mount the EDF more to rear? That way you could maked better intake direction on the airintakes. Thats reason for you loosing close to 50% of effect... or more. You will not gain much by a "ram-air" effect here either.
Leaded50
The distance between the inlet and exhaust is fixed so it all comes down to which suffers the most from the lack of space. The inlet area is above the FSA whereas the exhaust divides & tapers down to 90%. My experience suggested it was more important to maintain a good exhaust path than the inlet given the inlet velocity will be only about 80% of the exhaust.
Surely 350g thrust down from 500g is a reduction of 30% not 50!
I am building the plane to take into account the limited thrust. It should still fly adequately on a 70% thrust to weight ratio particularly given its generous area & un swept wing. It won't be a 'rocket ship' but then neither was the full size. ;)
We shall see.