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Subsonic Mike's blog
Posted by Subsonic Mike | Mar 02, 2014 @ 11:06 AM | 1,139 Views
When I was younger I always wanted a tracked vehicle. Still do somewhat.

Combine boredom and spare time and this is what you get....


A very easy to build wading tracked vehicle

...Continue Reading
Posted by Subsonic Mike | Feb 18, 2014 @ 06:20 PM | 1,909 Views
Needs cleaning up, but heres what you get when you stick a pair of swing wings of a lifting body:

Wings forward, quite a gap behind the wing. I should probably fix that

Wings back, much cleaner like this
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Posted by Subsonic Mike | Feb 15, 2014 @ 07:47 AM | 1,319 Views
Finally got this one finished:

1m span, 3 30mm edf's and quite compact with the wings off. The wings start just after the fins

Not the prettiest from the top
...Continue Reading
Posted by Subsonic Mike | Feb 14, 2014 @ 04:21 PM | 2,041 Views
Im still tinkering with blended / lifting body aircraft here in Britain,

Heres the latest:

I call her HSRV-2 (high speed research vehicle 2, aren't i creative?)
HSRV is a 1200mm span rocket powered aircraft that I would love to build one day when i have the money. Im aiming for 200mph+ But any speed above 70 would provide valuable data on the flight envelope of blended bodies.

Here some more images:

Front View
...Continue Reading
Posted by Subsonic Mike | Oct 13, 2013 @ 09:38 AM | 1,656 Views
Well I might as well show these off in my blog:


...Continue Reading
Posted by Subsonic Mike | Jul 26, 2013 @ 11:08 AM | 1,909 Views
Today I did the rest of the lifting bodies frame.
2 hours of very fiddly work. But I can say it was worth it, for I now have a frame ready for tissue covering. The weight so far is 13g, 2 grams lighter than the ribs before they were sanded and slotted.

If I can generate enough interest, when I have finished the model I will make full plans and building guide for free download.

Enjoy!
Posted by Subsonic Mike | Jul 25, 2013 @ 04:15 PM | 2,189 Views
Its started! the second lifting body is finally underway!
Man I cant belive its been over 2 months since I got the balsa... Time and school got the better of me (again).

Well here is the beginnings, enjoy!

Construction notes:
Its built from 1.5mm balsa and will be tissue covered.
Wing span = 132mm, length = 300mm
Construction method, Boxy, like the last one (I think its called egg box construction?)
Tomorrow I will finish of the balsa work and get my Dad to teach me how to tissue cover.

Thanks!

Michael
Posted by Subsonic Mike | Jun 03, 2013 @ 09:46 AM | 1,947 Views
Im back!
Im almost done with those blasted A level exams and soon to building again!
That means my second lifting body will be made soon[ish]

Since I haven't been able to build much recently I have been testing and tinkering with my current lifting body. Im proud to say that its completed over one hundred flights!
Its also had 5 nose repair jobs, a new launch hook, 8 sets of fins and 3 sets of elevons attached. The latest refit is the most major in terms of performance.

Over a 3 week period I spent roughly 10 mins a day (give or take) on a CAD model of a lifting body park jet. I completed this yesterday. This lifting body is based on my current one but is double the size and man small tweaks have been made to improve its performance.
Since my current lifting body is closely related to this parkjet I refitted it to make it a scaled down version.
I changed the elevons added a imitation motor and ballasted so its a scale weight. (its 20g over my target weight for the parkjet.)

Michael
Posted by Subsonic Mike | May 11, 2013 @ 07:56 AM | 1,915 Views
I now have the balsa I need to make the second lifting body.
Im now waiting until i have time, that could be when my exams finish (4th june)...
Soon to be made!

Michael
Posted by Subsonic Mike | May 07, 2013 @ 01:42 PM | 5,172 Views
Well I was messing around today with my lifting body (now called Alaminus) , just trying things out. I tried things like different fin angles and CG
Then for some strange reason I though of dihedral and how I have notice many lifting body (ish) Nasa aircraft (1*) have had a flat top but with a V shaped lower section.
I then my mind must have put 2 and 2 together and thought maybe dihedral could stabilize aircraft with just the lower surface at an angle. I never looked into how dihedral works, I just knew it stabilizes aircraft...

No point wondering, time for testing!
And in the usual bodging spirit I grabbed paper and tape and added a temporary new section to Alaminus and threw it...

I can safely say it works, its now too stable!
Before the extension, Aluminus would slowly rock back to horizontal after a bank.
With the extension, I cant roll it without going inverted! Its like its on rails. I threw it at a bank of 45 degrees and within 10cm it was horizontal.
But I now it has a nasty stall, nose up one wing down spin. (death stall)

Test success and 0 spent.

As always, If you have any questions just ask.

Until next time, Michael


Notes-
1* this flat top V bottom is very vissible on Lockheed's Have Blue (link).
Posted by Subsonic Mike | Apr 30, 2013 @ 01:43 PM | 2,158 Views
As Rolf Harris said, "can you tell what it is yet?"



(no prizes :P)

More will be soon! (week or two)

Michael
Posted by Subsonic Mike | Apr 15, 2013 @ 12:41 PM | 2,326 Views
Making a aircraft design is one thing, knowing how aerodynamic it is and how to improve this is another.
Ever since I started to make aircraft designs I would like to one day make into proper RC Models, I have wanted to put them in a wind tunnel and improve them. But I don't have one and making a accurate one isn't exactly easy- or cheap.
I then found out about Computational fluid dynamics (CFD).
BUT CFD didn't come cheap; and when I did find some open source CFD there was no clear instructions on how to use it or even install it.
Then I found a lifeline. Autocad (autodesk) have a piece of Software known as Project Falcon.
From the moment I saw the words CFD and Free i though, whats the catch? Hard to use? Hard to install? Only available for a free trial?
None of the above applies.
You download, install, find a .obj (or export one from your choice of CAD software) and just use it.
The simulation runs smooth and can simulate airflow up to 1000 m/s.

And if here are some screens: The first is the sub in my avatar, with a head wind of 5m/s, the second is my A-46 Strike master at 680 m/s (mach 2)

Project Falcon Link

And as always, if you have any questions feel to ask!
Michael
Posted by Subsonic Mike | Apr 12, 2013 @ 09:08 AM | 1,940 Views
I have now completed a small animated preview featuring clips from four of my main animations.
All models feature in the video were made by me.

Amination Preview (0 min 39 sec)


Enjoy!

Michael
Posted by Subsonic Mike | Apr 11, 2013 @ 04:54 PM | 2,085 Views
Well I love to CAD, have done for 3 years. Although it was only a year ago i developed my own technique and started to make nice scale models.
Then about a mounth ago I found out how to render these models.
And I think now is the time a few came to light....
Any comments are accepted.

Album can be found here

Michael
Posted by Subsonic Mike | Mar 29, 2013 @ 12:12 PM | 3,428 Views
Well I decided add the fins, purely because they look nice and it was bugging me I didn't know if the flight performance would improve or unimprove.

The result: The fins ironed out all the strange flight characteristics at the extreme ends of its tested speed range.
It now mushes more than stalls, and dosn't flat spin at higher speeds.
Im still planing a balsa/ tissue one, when I have time...
Posted by Subsonic Mike | Mar 23, 2013 @ 01:16 PM | 5,911 Views
After an hour searching the internet for anything on how to design a lifting body and finding nothing, I decided to bite the bullet and attempt to design one.
So of to Google Sketchup it was for some CAD time!
Skip forward 2 days of on off work, and I have come up with a method to design lifting bodies. But would it fly?
Im not made of money so I cant afford to make something nice out of foam, balsa ect, so I decided to try my new found skills in paper modeling.
So, about 4 weeks since I started the CAD I have a lifting body on my lap.
But does it fly?
First throw: It pitched down and rolled violently to the left. That was a nice surprise, i didn't expect it to fly better that a brick
Second throw: Added a tiny bit of the well know ballast, Blue Tack, to the back right. It flew in a nice straight shallow line but continued to roll left.
Third throw: Added a small trim tab to the right. It now fly's nice and level in a gentle slope, although the drag from the trim tab does cause some yaw.
Throughout these flights something had been bugging me, I now realise as I type this blog. Its missing its 2 vertical stabilisers!! Well since it flys fine I think I can safely say it doesn't need them .