combatpigg

My Feedback: (3)

I haven't been a member of this forum all that long and it seems that everything has already been done at least twice. I don't know if VTO and L is doable with the limited knowledge and with the limited talent that I have in my thumbs, but it seems like the next [ and most interesting ] challenge. I don't have any experience with gyros, but I'm sure one is going to be needed, as well as a way focus the prop blast, maybe some kind of cone shaped shroud. A plane like this would have to be a series of compromises made in favor of take off and landing mode success, and forward flight regime could be mediocre and I would still consider this thing a success. I have seen some of the contraptions that have been concocted by the VTOL guys, but they seem to lack precision, and the landings look like white knuckle time. I think a threesome of 061s that are dumping thrust into a common shroud [lamp shade]could supply over 3 pounds of ooomph, and if a simple machine could be built in the 2 pound range[ or less], then the only thing holding this project back is ideas. 1 or 2 of the engines could be left running full blast, and only the third would be needed for thrust management. on the other hand you could have 3 AMEs running WOT on bladders, and control the thrust at the shroud with a shutter[s] I can foresee spending lots of time with tether control testing before setting something like this loose on the public! Any and all "chimers in" are welcome to deposit your ideas for this one.

bigchap

how about ducted fans on swivels?a la blimps,seems the simplest way to go,i think you would probably have to have a way to shift the CofG to make it successful.

BMatthews

If you want to consider a new form of model that owes very little to scale then a lot of possiblities open up.

A Harrier like model using two ducted props in fuselage side mounted nacelles sort of halfway through the wings. So rather than thrust vectoring the engine mounts swivel (sort of like Bigchaps idea). Now to maneuver the model I'd also consider taking another page from the Harrier's book and provide some high pressure air to "jet" nozzles at the wingtips and tail. Simple gate valves connected to the ailerons, elevator and rudder would open and close the gate valves to direct a puff of pressurized air as required. I'm not sure what would provide the air for maneuvering in the hover. Perhaps a GWS ducted fan unit. It only needs to run while the model is in hover. But then it also means you need to carry more batteries. The other option would be to figure out a way to side track some of the fan blast from the two main engines.

The tail sitter models are another possibility. But as you say you need to be pretty good at hovering.

PS: OK, call me a party pooper but I changed the name of the thread so draw more SERIOUS attention...

combatpigg

My Feedback: (3)

I have given this idea a little thought and feel that this thing needs to be able to land on it's tail. If I had a couple gyros to help stabilize it in decent, the majority of the workload would be just the management of thrust. I can see how this thing could be done with electric motors somewhat easier, but to me they are a seperate hobby that I'm not into yet. The way to handle the CG shift would be to make the engines movable on a sliding track, but this is an area where I would have to call on the experience of the VTOL gang to say how much shift is needed, and I'm sure there is no definitive response to that question. One of the main reasons why this project interests me so much is that I haven't seen any outstanding examples done[ in the model world] yet and there is an opportunity here to do improve what has already been done and have a good time doing it. I guess a line has to be drawn somewhere to keep this thing from becoming, and looking like a poorly designed helicopter. I think it should look like a rocket plane from an episode of BUCK ROGERS! Well maybe not THAT cool, but it has to at least fly on the wing in level flight.

matchlessaero

CP, when I designed the first Half-Wit, I was also toying around with designing a 'tail-sitter' VTOL powered by an .061. I went through several ideas on my 'mental CAD sheet', but all seemed to be based on a 'tripod' of carbon tubes with the engine on the top of the tripod. Wings would attached inside the tripod to essentially build a delta with a big vertical(on the bottom of the wing). I got that configuration idea from a couple of 'Wings' shows on the Discovery channel and a picture I saw of a similar .061 powered plane on RCGroups.

With a weight of 12 ozs or less, it would be easy to get the vertical pull right......

Hmmmmmmmm, now where did I put that set of Spider Delta ribs................

combatpigg

My Feedback: (3)

HEY MATCH! Your idea sounds like the most direct approach to handling this assignment. The skill needed to land what you are talking about sounds about the same as the other examples that I've seen, where it takes practically a full tank of gas to land after take off! For landing gear, carbon tubes that had a smaller tube slip fit inside, and spring loaded would work, or maybe music wire cat whiskers would cushion landings? To make this idea easier to land some balanced thrust needs to be exerted at the outer extremities, via air ducts that funnel down into nozzles. They could double as structural support[of course] and the visual image of 4 little dust plumes is too cool.The force exerted by the ducts wouldn't come into play until inches from the ground, but they might make the job of settling in for touch down easier. This is why I think a multi engine setup is needed, because one engine putting out 24ozs couldn't supply much more than the simplest of ideas, like your DELTA with the landing tripod. I'm going to try and set aside some time to sketch up something for tonight.

ZAGNUT

My Feedback: (1)

ahhh yes, the tail sitter
i have an FMA FS8+co-pilot on the way just for this type of delta plane! i plan to take the sensor module apart and mount the thermopile sensors seperately throughout the plane, one in each wing tip and one in each verticle stab tip.

the retract channel will turn the co-pilot on/off. when i want to land i'll just flip the switch and the plane will assume the position needed for landing...all that is left is to throttle back. another plus is the failsafe function that'll land the plane for me


dave

flyinrog

My Feedback: (1)

There was one in RCM years ago that had a jet like look, with a nacelle in the center of the plane that pivoted using a small electric motor that had a threaded rod through the side of the nacelle,, the servo actuated the motor so the nacelle moved at a controlled rate when transitioning from hover to forward flight...Rog
it was not 1/2a size,though ,,I believe it was a .60

combatpigg

My Feedback: (3)

WOW ZAGNUT! Sounds like you've got it all figured out! I can't afford to devote that much money towards this project, I figure the 2 gyros, and maybe a winch servo are about the only "high tech" goodies that I will throw at it. Once I get my flying machine set up for a vertical landing, then I see using a winch servo to pull the flying portion of the airframe forward to put the engine, tank, battery and rcvr as far aft as possible. This should relieve the pilot from doing much pitch control work, and keep his mind on finessing the throttle[ thrust control].

HI ROG!, The rotating engine /motor designs just allow the plane to pancake in, and my heart is set on a lunar landing type approach!

jessiej

There were two experimental VTOL (take off and land like a sci fi rocket-on the tail) in the late 50s-early 60s.

One was a jet, the other a turboprop with a big counter-rotating prop. I seem to recall that it was by Convair.

I would envision a VTOL model looking something like the turboprop.

jess

Japanman

Yes, my thoughts exactly... but just imagine what would happen if one engine went out!
AAaaah who cares! I like the idea of two wingtip mounted engines rotating 90deg... 'twould be fun to make!

J.M

Lynn S

I remember the turboprop plane and even built a plastic model of it. I guess it would have been a really strange looking fighter and a slow one at that. I wonder if it ever flew? Seems like all I ever saw it do on tv was hover...guess it couldn't blast off like a rocket.

N1EDM

My Feedback: (2)

That VTOL was called the Pogo. Actually, I think there were two designs by two different manufacturers. I just can't remember the second variant. But maybe an Internet search on Pogo +Airplane might turn something up about both of them.

If I remember my history correctly, the Pogo had twin contra-rotating props and was the only one of the two to take off vertically, make the transition to horizontal flight, then make the transition back to vertical flight and land.

One of the complaints was that pilots couldn't see the tail of the airplane properly to land vertically. I guess no one ever taught them how to back up an airplane in flight?? "-D

Just adding my $.02.

Bob

ZAGNUT

My Feedback: (1)

[link]http://www.nasm.si.edu/research/aero/aircraft/convair_pogo.htm[/link] very interesting read! thanks for the name Bob, it was a cinch to find. with today's technology it seems like it would be easy to make this plane a reliable performer


dave

flyinrog

My Feedback: (1)

well, pigg, I'm not sure what a pancake landing is but, this one took off vertically, transitioned to forward flight and slowed to a stop and landed(from a hover) vertically,, so I'm not sure ,,do you want a plane (vehicle) to have the engine at the top, take off, and then kind of just drag around in flight so that it can land on its (?feet)? or are you talking about 3D stuff where a stunt plane can stop on its tail ,cut throttle and fall on its wheels? just curious.....Rog

T.W.

http://www.rcuniverse.com/gallery/ga...lery/index.cfm

combatpigg

My Feedback: (3)

HI ROG! No, I misunderstood what you were describing, this plane is going to descend and take off with the nose pointed straight up.

Thanks to all of you who have contributed to this brainstorming session! The story about thePOGO and the extreme courage that it took to fly the thing was impressive. Another story about our TAX DOLLARS hard at work in pursuit of what I don't know. I think in 1950 those guys were getting a little bit too big for their britches, back in the day when transistors were considered TOP SECRET!

With the use of only one engine, 12 ozs is the absolute limit for weight, and to refresh your memories about what you can make with 12 ozs, take a look at some of the 1/2A creations that have been submitted to this forum and you will see just how limited that is. This is why I think it needs to be powered by 3 engines. The thrust control needs to be centrally located , the center of mass should be as contained as possible, and having engines stationed like outriggers could prove to be a hand full in forward flight. If we were playing with electric motors, then I would be all for outboard thrust control. The only unorthodox mechanism I can see having is the sliding radio compartment/ engine mount. In forward flight the vertical fin could be on the bottom, to help with stability, and the foreplane would be providing lift and stability. The centersection could telescope out to make the plane stable in forward flight also. The only way I can forsee doing the CG shift is with a winch servo, and that is a bunch of dead weight if the CG shift proves to be unneccessary for stable touch downs. Right now I think it is a good idea, the shift would have to be in the order of several inches to make it worth having.

mclintock

My Feedback: (3)

I think you should make a twin ducted fan bell x-14...
[link=http://www.kulikovair.com/VTOL.htm]cool page of vtol craft and almost some model stuff[/link]

I like the x-14 cause it looks like an airplane.. mostly..

ZAGNUT

My Feedback: (1)

CP, cane me if i'm wrong, but wouldn't it be better to have the CG farther forward for lift-off?? like having the weight dangling as far as possible behind the thrust generator?


also, you can forget the sail winch... take a micro servo, remove the stops from the output gear and remove the pot. put a small pulley in place of the arm and use a cable wrapped around it and attached to the fuse ends...the "winch" servo should be mounted to the tray and a pair of micro switches+resistors wired in place of the pot will define the end points of the tray's travel. been thinking of doing something similar for a 3D plane in order to alter the CG during flight.


dave

combatpigg

My Feedback: (3)

HI DAVE! You are absolutely right about the CG for lift off, I just want a rear CG when landing. I don't understand how servos work, but if you think a HS 81 could be modified to act as a winch, that would be excellent!!! I see this thing having three evenly spaced wings, the one that is designated to be the fin could be a contrasting color, Flying fin down will give the machine some serious dihedral! I think that it could be flown elevon only, but for landing stability it might be helpfull to have an all moving canard. I don't like the idea of lugging around gyros if the stability in descent can be accomplished with average pilot skill, but one gyro could be used for yaw control in descent while the canard is contolling pitch

Hi MCCLINTOCK! Thanks for the link to the BELL X14! I'll give it a good look.

mclintock

My Feedback: (3)

Here's the other vtol plane I used to think could be modeled as I used to sit in study hall trying to stay awake...
so long ago..
[link=http://1000aircraftphotos.com/PRPhotos/RyanVZ-3RY-1.htm]ryan vertiplane[/link]

Was everything really black and white back then?

oo here's more-


[link=http://208.56.150.96/wheel/wheel.htm]the vtol wheel![/link]

clint

zoomzoooie

Gee! I'm a bit late jumping into this one.

I had brought up this subject when AJ posted his counter rotating VA engine.
I asked him if they would have enough thrust for a VERTOL project I have been contemplating for years, only it was originally to be for a larger model.

Following the concept of the V22 Osprey, I thought about using heli parts for the thrust set up so you can have complete control of the rotors to make a more stable controllable aircraft. The control surfaces would have to be 1/2 cord to allow thrust past the wing as in the V22. Most of the V22 concepts would have to be used to have a successful flying aircraft.

Now with all the micro heli stuff out, this should be viable for 1/2A now. I think this set up will give the best thrust to weight ratio because larger rotors can be used. The only major draw back is a single engine failure. You could use two engines per rotor or a flex cable (like a dremel extension) and gears could connect the two rotors with a clutch set up but engine power with one engine might not be enough for a controlled descent so auto rotation would help. Now the problem is keeping all this complex machinery light enough to get off the ground.

You guys with all the tools to make stuff would have a blast with this type of project making your own parts. Hint, hint

ZZ

combatpigg

My Feedback: (3)

HI ZZ! Glad you chimed in! The multi engine idea is frought with danger, a scenario of not IF it will crash, but WHEN will it crash? Electric motors would make life easier, but if it was supposed to be easy, then the GIRL SCOUTS would offer VTOL DESIGN as a merit badge! I like the weirdness factor of 3 wings and 3 engines though. I might try something like MATCHLESS described first, just one engine at the top of the tripod. I am dissapointed to hear that the RC AME isn't as strong as the CL version. I am going to feed a CL version with a combo fuel system to give me bladder at WOT, and suction at throttle barrel positions from 80% on down. My NORVEL 074 doesn't seem to be a strong one, it only gives 16500 with a 7-3 APC, and it was easy to break in, but it might be better than a huffin and puffin AME? The big rotors cause a counter torque that may need a helicopteresque fix to solve, and I don't want to get involved with copter stuff too much. The .074 might be able to handle a custom carved 8-2 or 9-2 prop which would make fine control of the thrust easier to do, provided that it can deliver enough to begin with! The only way I know of to soup up an engine to handle a bigger prop is with more stroke and compression, there just aren't any small glow engines that are beefy enough to handle much load. I don't know as much as I would like to about the MP JET 061 diesels. IF THEY WERE SO HOT, why don't you see more of them?

zoomzoooie

CP, your probably right about the "when" it will crash and yes you would definately need counter rotating rotors for this type of design. I think a cog belt drive would be best and easy enough to set up the counter rotating rotor system and this would be the all time "challange" project. And thinking about the power factor of these small engines, maybe two or three per rotot would be the way to go.


I remember seeing, in one of my old magazines, a wierd concept with twin engines and a fusleage that hinged downward. I think it was the front of the fusleage that moved. I can't find the magazine so I'm going on memory. I remember a pic showing it sitting on the edge of a table with the fuselage hanging down. In this postision the wings and wing mounted engines faced virtical. It was a wierd concept. I can't imagine having to take off from the edge of a table let alone having to land on one![X(]

I also remember seeing somewhere someones success with a mid mounted lift engine and a seperate thrust engine for a Harrier type take off. Its seems to be the simplest setup using a more or less conventional airplane design. It might have been a delta design...

There should be and "X" prize for the first successfull 1/2A VERTOL

ZZ

combatpigg

My Feedback: (3)

ZZ, one thing that struck me funny reading about tilt rotor planes is that the prop disc doesn't want to rotate, the airframe just moves in the opposite direction[X(]! A triwinged delta with gyros and CG shift seems within the realm of possibility to make happen at a weight that 3 061s could handle. Having 2 pitched props will also mask differences in rpm between the engines. And to top it all off, it's going to be like, weird, man[8D].