vtol_guy

hi everyone

just realised that there seems to be a few people attempting a vtol. I think its best for all ideas to be shared in this one thread here so its more simple for everybody. I've been working on VTOL's for over a year and have gone through 2 designs and makes so i'm pretty clued up on all this stuff and all problems so any questions just ask! [8D]

Hover Dude

hi i am considering building a vtol. it will be more of like a flying car and it will be electric. right now i am looking at around 2lbs and it will be running of 2 geard 4-1 480s running a 16-4 props. when you varied the speed on your motors to control the roll didnt that induce any yaw. also were your props counteroating? any sort of info will be very helpful.

vtol_guy

hi,

the engines i used had the props spinning the same direction but the torque reaction can be easily cancelled out using the elevons to control yaw if you are building a tilt wing design. my 2nd design used 2 gyros to stabalize roll and yaw axis. Gyro rates have to be set to high to make it easy to control though

using the elevons this way is only really successful in 2 circumstances. The 1st being that the engines/ motors have to be fairly inboard in relation to the wings, the furthur apart they are then it needs less force to affect it. 2nd is that i don't think this can be used on anything over 2 size .70 engines.

vtol_maverick

hi guy, just call me Mav.
thanks for the info on the tilt servos. it saves me busting lots of them.
Space is precious in my fuz, so I'll try a winch servo to start with.
I'm using a vacuum forming machine at my college to make my moulds, which is really quick + simple. So hopefully the entire thing can be made in moulded carbon fiber. The wing will be a built up structure, with fixed composite panels over the top and removable panels on the bottom.

have you had any problems with fuel supply when in different roll attitudes? I really don't want to fiddle around with perry pumps to suck it through the wings.

ps. what sort of gyroscopic forces have you found when transitioning the rotors?

vtol_guy

the engines operated fine in any attitude that they were placed in. You're using electric motors anyway so it should probaly be easier for you as they're more accurate than engines. With the rotors/ props whatever you want to call them lol, they have a tendency to want to stay in the same place. If you imagine the v-22 with engines vertical. Lets say that it was in a hover. As soon as you start to tilt the engines, they want to stay in the same place so the fuselage will start moving instead of the rotors so it should be going up. To cancel this out just pull back on the stick so the elevons keep the fuselage level with the ground and the rotors are tiliting forwards. Tilting from horizontal to vertical is a little less extreme as you don't have all the force there at first since you'll only be increasing from cruise throttle setting, however, the sudden kick up that it gets from cruise will probaly shoot the plane straight upwards which will make it a bit hard to master the landing but should be easier over all once you have gone through it a few times.

vtol_maverick

sam, Im not using poofy electric motors! thats the other dude (no offence mate!). Im running 2x RCV 60s.

I checked out your site, - not bad. From what you've said, it sounds like you're rotating the wings on a limbo dancer? any pics?
How have you fed wires/tubes through to the rotating section? is it worth using hollow section axel?
How do you plan to control roll in hover mode? My design resorts to using thrust vectoring from a v.small ducted fan, fed through the wings for roll, and a 'pod' on the end of the tail for yaw + pitch.
The end product should look like a BA609 with a small extension on the tail for the vectoring.
It's cool that you're building on such a tidy budget. Mine better bloody work, as I'm chucking a grand at it.

oh heres a dumb question,- in simple terms, what does a gyro do, and why do we need one in a vtol? does it only cut in when in chopper mode?

Going a tad off topic, I can see exactly how you got into vtol, us younger flyers need fresh challenges, and it doesn't get any fresher than this!
Last year I re-hashed the fuz of a wot4 to fit a s.tigre 90 on a tuned pipe. Went like a missile! But I busted it when attempting a rolling circuit 15ft off the deck.- still makes me mad...

vtol_guy

hi mav, sorry about the mis-identity problem there

the site which you saw was my very first design, forgot all about the site actually. New model though will be based on limbo dancer and rotating wings.

To feed the wires through, i was using a hollow square alum. tube. At the point where it ran through the fuse (round section to allow for rotation) i had balsa blocks smoothed round and ran them through there but if you have access to a drill (which i didnt!) then just run them through the alum. bar.

I don't know much about ducted fans so you'll have to look into that yourself i think. The way i did roll control was to vary the throttle setting on each engine eg reduce left engine throttle, left side goes down as theres less thrust there.

A gyro basically is a small extension of your brain! In simple terms on the roll axis for example, because the engine timings are so crap tiny adjustments have to be made several times a second. If your plane starts to roll to the left for example, the gyro detects it and feeds in more right throttle to compensate keeping it level and this action is virtually disabled when you are actually moving the controls.

I first got into vtol's before i could even fly! [>:] Thankfully though i can fly now, i just moved from a 3ch glider 2 months ago to a fun fly and i'm doing fantastic with it, don't think that some club members are happy with it but if they complain then i'll tell them where to go[>:]

s.tigre 90 on a wot 4???!!! Not one of saddams henchmen are you? lol, not surprised it went like a missile, how much tail ballast you need?? Could have mounted a s.tigre 34 on the rear end with a pusher prop hehe

vtol_maverick

I've forgoten how much ballest, but I used up all my fishing lead!! plus, the rud/elev servos were as far back as possible.
The fuz was basically made around the engine, pipe, f.pump and f.tank, - as thin as possible, and custom cowel over the G90. I was branded a real maverick when folks saw what was under the hood!!

bach to topic - (sorry mods.)
Thanks for the gyro info, I'll add it to xmas list...
When my vtol is ready for testing, I hope to rig up a safety teather, attached to the CG, from a big tree or similar. Then I woun't need one of those goofy heli training U/Cs!

My axel will travel the length of the wing to each engine naccel, so hollow alum is too soft for me. I'll look for s.steel ones.

What stage of build are you with the "converti-dancer"?

vtol_guy

the alum. one i had was rock solid, i had a lot of weight on it and it showed no sign of warping whatsoever.With VTOL's weight soon starts to build up, trust me choose the lightest things possible. This is why my latest vtol is based upon a limbo dancer (extremely light!)

My converti-dancer (nice name i think i'll take it hehe ) needs the wing building. Seeing as its used in conjuntion with my limbo dancer (i want to be able to switch between each) i need a new wing building and some modifications to the fuse. For vtol i'll have to put on the new wing, slide in the rotation arm and mechanism and remove the engine up front. Whole proccess switching round will take about 1 hour i reckon. If it works well then i'll eventually get round to building another fuselage for the limbo dancer so it'll be 2 seperate models

You started the build of yours yet?

vtol_maverick

Thanx, I'll test out some different materials from my college, as my n.diploma project is making the shaft and engine naccels.
I never really thought about converting a kit plane, so your idea is certainlly original.

Weight is a concern for me, as it will carry 600g of fuel, lots of servos, retracts, d.fan engine and ducts. However, most of it will be moulded carbon fiber, which should save the day.

I've run in both the RCVs -(runs perfect), made the male mould of the engine naccel, and drawn up the plans for most of the plane.
The main delay is money, as I need a ff9 radio.

vtol_guy

glad to here things are going well. Are you sure you need an FF9 radio? I managed to do mine on a 6ch radio, only using 5 of the channels and 2 v-tail mixers. have a think anyway and let me know if you'll go with the 6ch instead of computer radio so i can explain the way the v-tail mixers are connected up.

Sam.

wyflyer

My Feedback: (7)

Hey guys,
I am interested in building a vtol too. I have had interest in vtols for a long time, but I am just starting to research it. I have enjoyed reading this thread. I have been flying for 4 years and I have built 1 kit, 3 arfs, and I have 2 kits in the process of being built. I am interested to see what becomes of the converti-dancer and the other unnamed molded carbon fiber vtol.

Sam, I was wondering if you have a way to post some pics of the veetol. I would be interested to see it. It is the kind where the whole wing tilts, right?

Ryan

vtol_guy

you're lucky as i've managed to find these, completely forgot i had these, no pics of the converti-dancer yet as i still need to plan a few more things out first.

This is the 2nd vtol i built below, dont think any pictures of the first one exist on the computer

vtol_maverick

sam
It sure is tempting to reduce my costs, but many of the ff9 features lend itself to VTOLs. eg, one of the side sliders is ideal for the engine rotation, the flaperons can be linked with the engine rotate channel (like the real BA609), all the end points can be set from the tx and theres all the handy PCM features.
Hopefully it will be a smart investment, and I can't crash a tx!!
What were you using the v-tail mix for?

wyflyer

My Feedback: (7)

I have a 9c (ff9) and I love it. It works great and is a lot easier to program than the 6xas (ff6) which I replaced with the 9c. In my opinion it is a great value for the money.

vtol_maverick

Ryan, as your looking for design ideas, I would say that sam's philosophy is the safest and most likely to work, as he can use the flight surfaces for controlling hover. But it all depends how ambitious you are.
My design is not a strict scale model, but it is based around the new BA609 (google for it). The thrust vectoring will complicate mine hugely, which has put many people off the design.
Have you started favoring anything yet?

jh

hi there i have also been reseaching this subject and so far i belive the answer lyies with electric engines i was planning on useing 2 ducted fan electrics provided by rip max that produce a max of 1000g each ataching wings to them and rotating the while rotating the whole assembly for the transition to fowared flight and altering the thrust on each engine for lateral control at low speeds. I really think this will work..

any ideas

vtol_guy

i used 2 v-tail mixers, one which was for the roll in heli and plane mode, which dualed as throttle control. (on mode 2) the throttle was on the left stick as normal and the roll was connected to ch1 for roll control. In plane mode one engine going faster than other induced yaw action to roll in conjunction with using the rudder using a y-lead. The other v-tail mixer linked with the yaw and pitch. In plane mode the roll on the elevons wasnt used as it would be on the wrong stick for roll control but its always an option to use if i wanted to.

Being honest, the tilt wing is much easier to work with and much easier to make work, i'll be honest mav, i think that going straight into a tilt rotor is a bit like putting all your eggs into one basket as they say but then again you have a supply to excellent tool and machining facilities, thankfully at my school we've just had a new DT block built and we've got all sorts in there now, perfect for me! after i finish my gcse's next june though i'm off into RAF as an engineer, even better tools there!!! [>:][8D]

spent tonight building a new wing for my limbo but this isn't to do wit the vtol, its a swept forward wing for experimental purposes, because of money problems i think its gonna be at least february until i can start with building it.

mav, don't suppose those RCV engines can run backwards can they? If they can then it'll make things a hell of a lot easier for you. If they don't are you planning on overcoming torque reaction by the thrust vectoring?

vtol_guy

hi jh, just missed your post then

technically electric motors are better to use as there is more accuracy with throttle control and you can run one backwards to help with torque reaction problem. However, with eletric motors the power isn't usually there. I researched into electric and the only real solution i could find was to go with brushless motors and theres no way on this earth i could afford them or the controllers for it.

With VTOL's, weight does build up very quickly. You've got the weight of a standard plane, then with 2 powerplants instead of 1, then the additional servos, radio equipment, fuel, extra strength to compensate for more flight stresses, larger u/c, rotation mech, rotation arm....i could go on, weight kills VTOL'S, hence why im converting a limbo dancer.

Good thing about the limbo dancer is that its already very light, the 2 engines that im using come 20g over the 1 engine i had on before. I also only need 1 more servo than what i need before, the rotation arm can be small and weaker because theres less weight in the wing and i use smaller fuel tanks because the engines are much smaller. Only real weight is the rotation mechanism.

vtol_maverick

Sam, I'm typical dare-devil, so as strange as it sounds, I'm prepared to risk £1000 and about 4 months on something that MAY not work. - I'm not a Mav for nothing, you know!!!

I'll need 1 17x12 APC pusher prop, for the reverse engine, and check with RCV if it will run reverse. But I'm not sure it can be done.
If not, I'm hoping the vectoring should do the job, as most d.fans a quite potent.


ps. Help!! - people are talking about electric motors!! I can't stand the things, they sound more like Flying Food Blenders (aka FFBs), than real planes. (not that I would impose my opinion on you good folk...!!!)

Outburst over.
jh, can the ripmax fans be mated to .12 car engines? I only need somthing tiny, with a pullstart for my d.fan.

wyflyer

My Feedback: (7)

Mav, I think that electric motors might be best for your ducted fans, because they can be reversed and turned off. The two RCV .60s will probably make enough noise to drown out the ffb sound. Also I don't think that the RCV engines can run in reverse. You would have to change around the intake, exhaust, and glow plug ports. You might be able to do it, but I don't know how easy it will be.

jh

Hi there again i like those pics of yout aeroplane vtol_guy looks very inteating it looks a little heavy to me what is the all up weight?

Personaly i am an ic person not an electric but i have found a set of engines that will produce a 1000g max of thrust each at £30. I also plan on a light weight built up aircraft useing a basic stringer construction. I am not totaly after full control in a hover but if i use my flaps control on my transmitter to alter the pitch of the engines giving logitudinal control about the lateral axis and combine the rudder with the engines for low speed vectoring giving are lateral control about are longitudinal axis combined with a resonable sized split rudder plane it will wind cock into the direction of flight. EASY

Currently i am at the autocad stage makeing sure the whole thing will work, well it should i am an aircraft engineer my trade any way and i have been building rc aeroplanes since before can remeber.

I will keep you all posted on my work and will try and get some pics this weekend if i can stop playing freelancer.

vtol_maverick

Ryan, I may go against nature and consider an electric fan, but I have some Questions;
how much run time do I get, how heavy/large are battery packs and whats the cost of entire package?

vtol_guy

theoretically you'll be better off with electric but only if you can afford the costs involved. If brushless motors were much cheaper then im pretty sure a vtol ARTF would be available

eagle4

i'm not into vtol stuff at the moment guys, but i thought i'd post this web address fi you want to have a look, its about the moller skycar www.moller.com this guy has actually made a vtol car, (not exactly a car...) have a look if u r interested it might give you guys as idea for any further models you decide to make...