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Aug 15, 2021, 01:03 AM
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Originally Posted by Extreme_RC
No, the combos I compare perform within a few percent on the bench in static thrust, from actual flight testing, bench testing, I feel the CS rotor is not as good.

Again, I only go by what I have actually tested, thats why I have posted fan numbers, videos, data since 2005 from when I first started making my own tooling and producing dynamically balanced combos.

Again, I only go by what I have tested, calculators may give you a starting point, but real life use is what most of us are interested in.
Good luck with the build.
1) The CS fan may go better with a bit of a sand-up- If it is anything like APC and Airscrew propellers(the cheaper ones).
the blade edges are a bit rough.

2) I am more interested in weight targets, for now. Do you have any comparable builds and weights?
A full skin job with 1/32" is considered, along with tissue over sheet balsa, then paint.
There is a paintable covering called Oratex, but I haven't had a closer look yet - maybe next job?
There is one caller Oracover, polyester, iron-on.
I don't like the "plasticky" stuff particularly, but I will have a look at this.

I ordered a roll 2m for $35nz, locally.
I can get more from ebay, at about $20 US ($28nz + frt) per roll, if I like it.
I think it has a surface texture.
Next, to get a covering iron.
Last edited by Owen_bern; Aug 15, 2021 at 01:37 AM.
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Aug 18, 2021, 09:28 PM
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Two EDF units turned up today, with my XT90 plugs.
I seem to have ordered 3. I need to check my orders more carefully.
They are $110NZ each.
- Maybe another project in the future?? - twin wing-mounted versions.

Maybe a variation on the flying wing that I worked on for a while, 6 months ago.
Maybe this time I will have gathered better fabrication techniques...
EDFs would be no good for blow-over effects, but could do a stalled tailsitter-type landing,
and maybe a fast rotation through stall to vertical ascent? (lots of gyro).
Sep 20, 2021, 06:58 AM
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Interesting Mig21 variation.
I need to look these up.
This has a lower air inlet scoop. divided around the front UC retract bay.

This probably makes a lot more room for avionics, onboard radar, etc.
Last edited by Owen_bern; Sep 21, 2021 at 02:21 AM.
Sep 21, 2021, 02:17 AM
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This is a Mig YE-8 prototype.

Basically a Mig 21 with a different nose and airscoop, and an extra canard wing- this would improve high angle landing stability,
and improve low speed combat turn rate, and other fancy low speed manoeuvres.

Modern jets use these canards to allow moving the COG further back, and to complement computerised stability control.

At the age of this prototype, they may have just been starting experimentation with computerised stability assist.

This could have caused the ongoing reliability problems which forced the cancellation of the project.

It also allows actual onboard radar- which the Mig 21 couldn't carry.
The vertical tail form is slightly different, too.

This plane would have been a match for the Phantoms and Delta Dagger, of the same era.

This would make an interesting variation on my design plan, and allows a more reasonable intake cross-section and less obstructed air flow path.
The extra intakes and runners would not be needed.
I can use a lot of my marked up plans, plus the large scale Mig 21 plan set I have on hand, with suitable additions.
Last edited by Owen_bern; Sep 21, 2021 at 02:44 AM.
Sep 23, 2021, 05:17 AM
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Blend back the mig threads. 23 sept 21
Latest blended drawing, with old and new versions:
Sep 23, 2021, 08:47 PM
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Cleaned up drawing with colours.
1) Addition of a movable deflector flap for the front vents.
This helps compensate for velocity-induced pressure loss, and assists with flow inertia and the sudden angle change.

2) Addition of a less-raked and larger tailplane.

The wing leading edge rake is mainly to take advantage of the scroll vortex.
This is not desirable with the tailplane.

The wing rake also allows more span without penetrating the nose shockwave.

Shape adjustment also allows pivoting at the AC

The tailplane looks to be poorly located relative to the wing plane, but this seems common with supersonic fighters.
Last edited by Owen_bern; Sep 23, 2021 at 08:58 PM.
Sep 24, 2021, 03:24 AM
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I just thought of a simplification.- use slotted barrels instead of ball seals,
for the nozzles.
It would only need two, not four.
The butterfly valve can be rectangular.
One large one just behind the cog would do, but that clashes with the battery location.
The deflector plate servo can be linked to the shutoff valve servo.
The problem is , I need a load-limited servo to get a nice valve shutoff.
How would that work?
I will post the problem on the servo forum.
Problem partly solved- DuBro -style Servo Savers.

Now to get then to fit the 0.047rods. (1.2mm) 1.8 mm is too big!

Regarding split lines:
I can get a horizontal split below the wing if I step up before the tailplane.
Everything should be accessible from inside the EDF tubes and chambers.
I can make the main EDFs pull back into this space.

I don't think there is any major penalty from having a large cross-section,
low velocity area, and a converging taper before the tailpipe.
We shall find out!

Cross-shafts can have wall inserts which expose the retaining screws and blocks, or straps.
Possibly wall inserts can be retained by micro self-tappers.
Last edited by Owen_bern; Sep 24, 2021 at 05:36 AM.

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