Anybody else scratch building tonight?

[mastermalpass]

Began making ducts. The first part is a simple 90* elbow join that maintains the circular cross-section. I figured the simplest way to make these would be to start with some tubes and then slice them into segments. To get a nice consistent line cut through at a measured angle, I roughly made a little ‘line projector’ out of scraps and a laser:

I also made a couple ‘form holders’ to slip onto the tubes - they go a bit oval shaped if something doesn’t hold them circular. I now just need to figure out how many segments to cut from this tube and at what angles.

 

[Crash Test RC]

Fiberglassed, painted, and almost ready for combat. Heading to Edgewater Monday.

 

[mastermalpass]

Fiberglassed, painted, and almost ready for combat. Heading to Edgewater Monday.

That thing looks ready to rip a wing clean off!

 

[Flying Monkey fab]

Began making ducts. The first part is a simple 90* elbow join that maintains the circular cross-section. I figured the simplest way to make these would be to start with some tubes and then slice them into segments. To get a nice consistent line cut through at a measured angle, I roughly made a little ‘line projector’ out of scraps and a laser:

View attachment 244190

I also made a couple ‘form holders’ to slip onto the tubes - they go a bit oval shaped if something doesn’t hold them circular. I now just need to figure out how many segments to cut from this tube and at what angles.

I kind of hate the saying as it is so hackneyed but that is thinking outside the box! I would have never thought to approach that problem from that angle.

 

[Brian B]

Might need to sand the tips to fit the tube better. Picture suggests they aren't square. Scotch tape is pretty consistent for use as a shim. 3m electrical isn't.

Hmmm: Some do, some don't have better thrust. Tis what I discovered, even in the nasa data. Rings do act as muffler however.

Good point made about square tipped blades inside a nozzle being quieter and efficient. But I can report that normal tipped blades really scream inside a nozzle. This 3D printed "kort" nozzle is not length-optimized, more for scale looks, but it amplified the sound in the Nautilus, just as loud if not louder than the twin props running open in the Valkyrie. But loud can be cool!

 

[Timmy]

What is a good rule of thumb for the size of an intake for an EDF jet?

 

[Flying Farm Kid]

What is a good rule of thumb for the size of an intake for an EDF jet?

What kind of jet?

 

[cyclone3350]

What is a good rule of thumb for the size of an intake for an EDF jet?

It's been along time since I found the ROT on the intake szie. I believe that if I remember correctly, the intake area2 should be 100% of FSA. Fan Square Area. This could be two side intakes and a cheater hole added together to get 100%. There should be calculators on the web for plugging in your motor dia & the fan dia to give U the FSA. With that being said, I also think the ROT for the exhaust is 85% of FSA.

 

[CrshNBrn]

What a great thread. Post #16,609 is dedicated to the ongoing B-17, although building is at a glacial pace. Fitted the electronics and gear finally. No plans, just stealing and cobbling from other folks' ideas.

 

[Flying Farm Kid]

What a great thread. Post #16,609 is dedicated to the ongoing B-17, although building is at a glacial pace. Fitted the electronics and gear finally. No plans, just stealing and cobbling from other folks' ideas.

That looks amazing!

 

[Shurik-1960]

In sammer i live in a cottage in the village. There was free time from housework . I'm redoing a Sukhoi Su-57 Falcon : one of the two engines burned out (bad winding + poor quality wire). I bought a set of -4 engines. Jet Talon T44 received a new engine with a thrust of up to 1 kg.The old 2205 C engine allowed the pancake to fly.. A parcel with batteries for the aerobatic model of the aircraft was lost from China, I installed all the controls, it remains to make a container for the battery with the preservation of CG and a hatch. The flight will take place at the end of summer: I have re-ordered the batteries.

 

[bisco]

it will be beautiful when finished, i have no doubt

 

[Shurik-1960]

The SU is ready to fly with a new engine. Q4 -I check before the race on Lake Pleshcheyevo . This is a favorite speedboat that takes off over the water. This year, the Orange gyro stabilizer was installed.

 

[paradawks]

Just finished up this P-61 Black Widow from 13th Squadron. It hasn't flown yet, but I'm pretty confident it'll fly like my scratch built Flite Test P-38. I'd like to add a few details but wanted to get to this state for a scale fly-in at my local club next week. The best part is the turret is on a servo and rotates.

 

[skymaster]

Fiberglassed, painted, and almost ready for combat. Heading to Edgewater Monday.

when i first looked at the picture thought your had painted it with an army Camo.

 

[tomlogan1]

Not really "scratch building", let's call it an ARF. Crash Test Hobby Albatross. Great liberty taken with the shark teeth mouth. Still more to do.

 

[bisco]

looking good!

 

[Flyingshark]

Not quite a full scratch build, but I changed my Sea Otter over to an open cockpit with a hatch to keep out the water. I'm heading to a small lake this weekend, so I'm hoping to try out its new look there!

 

[FlyerInStyle]

Not quite a full scratch build, but I changed my Sea Otter over to an open cockpit with a hatch to keep out the water. I'm heading to a small lake this weekend, so I'm hoping to try out its new look there!
View attachment 244512

dont forget a pilot in that open canopy!

 

[Flying Farm Kid]

Just finished up this P-61 Black Widow from 13th Squadron. It hasn't flown yet, but I'm pretty confident it'll fly like my scratch built Flite Test P-38. I'd like to add a few details but wanted to get to this state for a scale fly-in at my local club next week. The best part is the turret is on a servo and rotates.

View attachment 244505 View attachment 244506

They are fantastic flyers. I run mine of of the ft a twin pack and a 3000 3s, fly's just like the MS P38. Mine is still white I have to paint it still. I did not hand cut mine though I have a Tim sav erc that I used to cut it out. Fantastic design from 13 squadron.