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May 31, 2018, 08:45 PM
Retired CAD guy
birdofplay's Avatar
Just Keep those AUX rx antennae out side of the aluminum for good radio coverage.
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Jun 01, 2018, 01:54 AM
You know nothing....
Stuart A's Avatar
Here’s KarlHeinz57 flying his big Northrop.Covered with flitemetal.If you can keep sight of a wing,a big tailed delta shouldn’t be be too much trouble....
YB-49 with 8 50mm EDFs II: Fourth flight (5 min 12 sec)
Last edited by Stuart A; Jun 01, 2018 at 03:22 AM.
Jun 01, 2018, 04:31 PM
What could possibly go wrong?
That YB-49 is fantastic. Very ambitious project to take on but a big success
Jun 02, 2018, 12:54 PM
Registered User
softshell29's Avatar
Thread OP

Crimes Against Aviation History

Love that YB-49. Surprising it seems to have less, not more, sun flash. Probably cause he uses gentler banks and since there is no fuse flash component at all--only wing flash.

YB-49 was a victim of Crime against Aviation History. Its opponents were not satisfied to beat it in the competition for next USAF bomber. They had to go further and get the government to order every example to be destroyed. Like they were not so confident in their own bomber's superiority afterall.

Reminds me of the ancient practice of a conquering King to not only kill his rival--but also have every member of his rival's family put to death. Barbaric. A tragic loss to aviation history. If even one had survived it would make a priceless addition to the Air Force Museum.

Same Crime committed against the YB-60 and the Avro Arrow. I think I will do one of these 3 as my next project. ..And using Arrow's tandem Mains on XR-1
Last edited by softshell29; Jun 02, 2018 at 01:01 PM.
Jun 02, 2018, 02:11 PM
Retired CAD guy
birdofplay's Avatar
I have been lead to believe, by a book about John Northrup, and his company,
that it was Floyd Odlum, of Convair AC, who coerced the War dept at the Pentagon,
to have the Northurp built machines all hacked up and the documentation taken away.

All as retribution for Northrup NOT WILLING to merge with Consolidated at the time.
An attempted Hostile Takeover.
Just paraphrasing a book here as I don't have a Stake in the game.

I have not discovered any other historians willing to make the claims found in the Northrup Book.
While there is some reference to "political games" they blame technical issues for their destruction.
Last edited by birdofplay; Jun 02, 2018 at 02:30 PM.
Jun 08, 2018, 07:54 AM
Registered User
softshell29's Avatar
Thread OP
Fuse is made of a series of 2 inch foam "donuts" ...They are glued together and reinforced with rollwrap carbon tubes.

Small roll wrap tubes ideal for RC are now readily available on Ebay and direct from China at moderate prices. They seem stronger and lighter than regular carbon tubes.

The alignment holes for the tubes in the foam donuts are 1/4 inch. The tubes are slightly larger at 7mm for a snug, slop--free fit
Jun 08, 2018, 08:00 AM
Registered User
softshell29's Avatar
Thread OP to attach the nose section since it has no alignment holes for the carbon tubes to run in. I could just butt-glue it, but need more strength to carry the loads from heavy batts in the nose.

Rather than carving channels in the exterior for CF strips, I devised this jig to enable drilling 4 holes in exactly the right place. The jig uses several of the donuts to hold a 1/4 inch brass tube with sharpened end. The tube is rotated to drill the holes--an old foam hole drilling trick. The donut jig holds the brass drill in the correct position.

Now the nose is supported by the roll wrap tubes the same way as the rest of the fuse
Jun 10, 2018, 06:53 AM
When cows fly!
Jun 13, 2018, 08:00 PM
Registered User
softshell29's Avatar
Thread OP
Mounting the 4-Pack on the 80mm prototype.

Fans mount on a 1/8 liteply firewall with its own donut which then slides down the 4 CF tubes to join the other donuts.

Seems too weak for a firewall--just 1/8 liteply. But it will be trapped in place by foam donuts on both sides . And EDF mounting screws go into 1/2 inch spruce blocks trapped behind the liteply
Jun 14, 2018, 09:13 AM
Registered User
jumo004's Avatar
Beautiful work !

Just wondering could you post a picture of the inlets ?

Jun 15, 2018, 08:34 PM
Registered User
softshell29's Avatar
Thread OP
Jumo, a very good question.

There are no intakes on a Rocket Plane, as you know, and that s why you asked. In a previous project I solved this problem by building a mechanism to lift the EDF unit out of the plane into the slipstream where it could breath better for high-power portions of the flight. .

That worked very well. But this time I am determined to keep all EDFs inside the fuse at all times. I am not sure how I will do this yet...... except that the nose gear opening is a natural candidate for intake. But more intake area is needed.

One way would be to use the many circular windows on the sides of this space ship. Here's an early idea I had, using camera apertures mechanisms with super bright chrome reflecting surfaces on each window. When closed , they would reflect light and look like windows. Or they would use clear plastic petal panes, and be see-through exactly like windows. . This vid is a much larger version by someone else I found on Youtube to illustrate. Its petals are thick and very visible. For a scale, aircraft appearance, look at a camera aperture mechanism to imagine how thin and pure this could be.
Mechanical iris fanblade design (0 min 26 sec)
Last edited by softshell29; Jun 15, 2018 at 08:46 PM.
Jun 16, 2018, 09:24 AM
Registered User
jumo004's Avatar
… maybe the side glass of the canopy could be left out and replaced with an inlet (painted black) along with the port holes and a few NACA ducts ….. and maybe you could get the FSA your looking for ? Looks like a fun challenge !!
Jun 16, 2018, 02:20 PM
An itch?. Scratch build.
eflightray's Avatar
Some of the scale EDF jets with small intakes use 'cheater holes', sometimes a hole on the underside with a lightly spring loaded 'trap door'.

When on the ground or low throttle the door can spring shut for looks, but under power the door opens inwards to allow air supplement to the main air intakes.

Perhaps you could have something similar where an intake 'door' can open inwards under throttle.

Jun 20, 2018, 09:06 PM
Registered User
softshell29's Avatar
Thread OP
Good ideas , guys. I'm not sure how I will do the Big One, but the prototype will use some similar measures.

Two large belly intakes with the retract well connected to them for additional intake area. All FOD screened, and 100% invisible from the normal view in static display and camoflaged with flat black paint for overflys. If this works, it could be a practical way to do other intakeless planes like ME-163, X-1 , X-2, X-15 etc.

Initial motor tests indicate the 90 degree intake angle will not be a problem. But I have so far only measured watts, not thrust, and have only tested each of the 4 fans alone. Already the fans closest to the intake openings produce more watts than those above them (so farther from intake). But the difference doesn't look too serious

However, I have no idea what will happen when all 4 run at once. My biggest worry is that the bottom 2 fans will Hog all the good intake air, and interfere with the airstream feeding the top fans. Just my speculation at this point. I look forward to resolving this question mark with actual 4-engine test results.
Jun 21, 2018, 01:42 AM
You know nothing....
Stuart A's Avatar
Great engineering on your build,really impressive!
Would an angled plate between the upper and lower pairs help to even out the inflow?

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