Quick shout out for my blog, I have got my website up and running. All the random stuff I do that isnt RC related will be put on there. This includes CAD and soon (I hope) details of the small liquid rocket I have been building.
Since college has finished I have had allot more time to CAD.
If I had a job, im trying to find one!, I would be building more. But somethings need to wait and this is one. So in the mean time I like to CAD.
And oh boy are finicky little details fun!
The image is rendered at 4675 X 2160 so be sure to zoom in!
Imgur link: http://imgur.com/a/XqEf5#0
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.
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.
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!
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.
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.)
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
1* this flat top V bottom is very vissible on Lockheed's Have Blue (link).
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)