|May 03, 2009, 08:37 AM|
sounds like youve been having fun kristian!
ive just been browsing on you tube and found these two videos,
the way he takes off on the truck gave me abit of an idea of how to test my wing,
my dad said they test the real wings with a rig on the roof of a car, and put sensors on to measure lift etc
obviously im no tech head so wont be using sensors but just feeling how much lift and stability its giving will be good enough for me!
check how much turbulence hes getting off the back of the lorry!!
theres another one with him landing on a mini roof too! guys got skills
|May 03, 2009, 09:50 AM|
wow! I have never seen those before! And definitely would be worth trying out that wing from inside the car, but only if you have a roof window, otherwise it probably wouldn't be that much fun : P
|May 04, 2009, 02:02 PM|
yeah itd have to be a convertable or have a sunroof lol
im thinking of using some fishing scales like below and attaching the wing to them somehow.. maybe on some sort of floating rig
havent really thought about it properly yet but you could go along in the car and measure how much lift the wing is giving at different angles of attack and - if needed- mod the wing and do it again to fine tune the shape etc
you could also judge the stability of the wing this way all without crashing once
|May 05, 2009, 01:04 PM|
yeah.. you could do that, although if you make a rig, it should be one with which you would be able to test different kinds of models as well, could be quite useful in the future : P. I'll let you figure out how to do that though
|May 17, 2009, 02:14 PM|
Ok, today I had some of my first experiences with free-flight
I found an old motor and a battery and a kite... so why not make a trike?
I modified the kite so it would resemble a rogallo wing and made the fuse out of toilet paper rolls :P strapped the motor and the battery onto the fuse and added a propeller (I attached a few picks). So now it was ready to fly, and it did! it went up and up in extremely steep circles (+-2,3m radius). It climbed into a height of approximately 200 meters and the cruised there for a long time before it started to descend. the problem was that to see all this, I had to run at least a mile to see all this, and then to retrieve the plane, since the wind carried it away. But I got it back... so why not try again? I charged the battery, it was dead calm so I thought it wont go that far now... well, it went further. We went chasing it with a car, but it landed in fields somewhere far away, we saw it all the time but for the landing... we were looking for it for a long time, but night chased us away. I got the knowledge I wanted though,and also some which I didn't want at all.
the only question is that the first time it landed, the motor would be still turning if it wouldn't be blocked by the ground, I guess thats the case now too.. can't the battery ignite if still connected to electricty, or the motor? I hope not...
|May 19, 2009, 11:50 AM|
LOL, nice one kristian!
has this given you the bug to start a proper one now?
i made a small wing today as i had abit of spare time, i wanted to see if the things ive learned about the wings could be put into practice and make a nice stable wing...
it glides really nice!
i made it with small carbon rod and ripstop put some nice wingsweep on it, some washout using balsa wood and a 'trike' using some string and chewing gum! took about 15 mins to make! lol
heres a few pics
|May 19, 2009, 01:27 PM|
Nice model you have there (couldve used domething else than a chewing gum though ! and yes, you are right, I t has given me the kick I needed : P
I plan on starting the build this weekend, I have already bought the electronics!
But before I do that, I would like you to answer me some questions:
1) what was the wingspan of your first trike? (the one on the vids)
2) what was the weight with a full tank of your first trike?
3) how necesarry is the leading edge airfoil shape? I would prefer to use only carbon
rods if possible to keep things simple.
4) I see that on your model the cross bar (is that how its called? I mean the stick that reinforces the two halves of the wing) is directly connected to the inner battens...
how does that affect the flying characteristics?
5) If the framework of the wing is a bit flexible... would that alter flying characteristics of the trike?
6) whats the general difference between the old style looking (diamond) and the new modern hanggliders?
After I have these questions answered, and after a tad bit more of research, I will start building the trike :P
Last edited by Kristian k; May 21, 2009 at 12:53 PM. Reason: added a few more questions :P
|May 23, 2009, 06:30 AM|
i was gonna use blu-tac but couldnt find any so used chewing gum instead lol
are you making a electric one then? im gonna try my hardest to make the nitro one work but if not im gonna go with electric power too-
it should be quite alot easier and much lighter too
its a last resort for me though cus i love the sound and smell of nitro!!
ill try my best to answer your questions mate
1 the last wing span was around 5.5 foot
2 i havent took a weight of the trike yet, the final version is gonna be a lot lighter than this one (if it works) by using better and lighter materials.
im starting to think lighter is better but it still needs just enough weight to make shifting the weight turn the microlight effectively
3 i think the leading edge shape isnt necessary if you are making a more old style rogallo wing and keeping the weight low (electric power)
im aiming to make a more modern hanglider type wing with battens and less billow so depends what type your going for.
the video below is a more rogallo type wing and he hasnt got a airfoil shape on the front of his and it flies real nice.
4 yeah its called the cross bar, the wing im building for my big microlight isnt going to be built like this smaller version- i was just testing the effects of reflex etc on the smaller model.
on the proper wings the crossbar is 'floating' -not directly attached to the keel, this allows the keel to move to the side when you shift your weight to either side- this will pull the sail tighter on one side of the wing (outer) and let it billow more on the inner wing acting abit like ailerons so will help the wing roll.
having the crossbar mounted like it is on the small model would probably work fine but i wouldnt do that on my proper one cus its not scale looking.
5 the frame work on a real microlight is alloy tubing and is abit flexable allowing the wing to adjust its shape when its flying, i think too much flex would make it fly uncontrollably or maybe not at all (as i found out with my first one without the flying wires! (cables)
having abit of flex reduces the effects of wind on the wing too cus it has abit of 'give' to it
6 i think the main differences are:
the old style ones (rogallo) were very stable in a straight line because of huge billow but werent very good at turning and flew VERY slow,
theyre more of a parachute than a proper wing imo
the rc versions of the rogallo type wings typically use a rudder behind the wing to steer as the wings are so stable that normal weight shift isnt effective (see bottom video)
the modern ones have less billow (tighter sail) and have battens to keep the wing shape so are aerodynamically better (less drag =faster)
and because it has less billow it is less stable so can handle much better and react to turn inputs quicker (the floating cross bar also massively improves handling)
hope these answers help you kristian and if you have any more ..fire away
rc hanglider type microlight
Last edited by mark675; May 23, 2009 at 06:52 AM.
|May 24, 2009, 02:53 AM|
thanks for the answers very helpful!
I am going for the modern style trike, it's definitely going to be controlled by weightshift, the wingspan will be a bit shorter than yours, I am not really sure about weight yet, but without the camera it should weigh about 550 g and with it 700 g... I might start making the fuse today. btw thanks for the vids : ) Ive seen all of them but one before though :P
I have two more questions:
1 ) the keel is being moved from side to side simply by shifting the cg and gravity then pulls it towards the inner side which then has an increase in billow? or does it move from side to side by som pull/string mechanism?
2) There are two types of wings: A two layered (which has two layers of fabric that are being inflated and together with the battens it somehow makes a cambered airfoil), and there the one layered wing, which has fabric going over the top of the wing only. could you provide me, if possible with a cross section view of both? (a sketch, or an image if you have, I coudn't find any)
thanks again, Kristian.
thanks : ) I will post a build log when the first prototype is finished : )
|May 25, 2009, 10:05 AM|
thanks, but I want to build a modern trike, this is an old style one : )
btw, are you originaly czech? or do you speak czech? I am form slovakia so no problem with reading czech sites : ) if you have any good ones, could you post some links?
|May 26, 2009, 05:12 AM|
Hi kristian Im not Czech...... but I range far and wide in search of unusal and interisting aircraft and plans and your country men seem to be very active but google translate does leave many questions un answered and will not work on some sites at all, my speciall interest is flyingboats/waterplanes but your skills and suggestions would be of considerable help..................if you wish to see my main reference thread click this http://www.rcgroups.com/forums/showthread.php?t=448080, there is a link in foamies to Rotohieds Hydro Rologo.
Kneeboy I was at studley on Sunday ...............I solved my foam board supply problem for building a mud duck, and rebuilt two mountain bikes for £20.
|May 26, 2009, 12:13 PM|
wow! excellent links! I couldnt find the rologo though, although I found the hyper bipe and the racer. Nevertheless, I guess my skills could be used, but not for translating instructions I hate even writing instructions... and my aircraft vocabulary isn't that good but if its for anything that wont take a long time, then I can definitely help.
by the way, if you are aiming for interesting and very rare concepts of aircraaft... check this video out, there is a very interesting craft called the thrustwing in the end section of the video... if somebody can explain me how this thing works, I would be grateful:
Last edited by Kristian k; May 26, 2009 at 01:01 PM.
|Category||Thread||Thread Starter||Forum||Replies||Last Post|
|rc microlight plans||FlyingKiwi||Electric Plane Talk||4||May 27, 2009 05:13 AM|
|Build Log||rc microlight/ultralite/trike||mark675||Foamies (Scratchbuilt)||11||Aug 29, 2008 09:25 AM|