V22 osprey

[rdresch]

This is a continuation of threads in multi rotor section. It would apear this is a appropriate location for the thread. Maybe someone else can post a link to those threads.
Rudy

[v22chap]

Cool ,,our own section ,,,now I have nothing to say :o :eek: :D ;) :rolleyes:
Hopefully going to get to play some tomorrow with the TH-2
Larry

[foamkiller]

ok i am here but it was geting a little deep back there .
:D i am all most stocked up to start fixed pitch twin electric . 10 x4.5 C.R.P's

[foamkiller]

i like the full wing tilt designe then airlrons can still work in hover mod as yaw/ roll inforward filght
like vtolman's hover vanes. differntial throtal for roll in hover /yaw inforward flight
& i think indance or aoa /&throtal for elavator
p.s. forgive me for spelling & gramatic anamlies i am dislecsic :cool: :cool:

[v22chap]

Foamkill
Sorry about that ,,but it is a complicated bird,,,if you want to do everything scale on it. Rudy and I are trying to put together a control demand for the onboard TH-2 mixer that Joe has designed and the mess back there was from 16 yrs of working on the control systems of a scale bird.The first day I sat down to the work table to start mixing and figuring out the controls ,,was somewhat the same feeling that I am sure you have right now ...but the best thing to do is start with 4 servos and start mixing them into each other and see what they do ,,and work with them until you have the control that you are looking for.My basic control is mix elevator to rudder in mix 1 ,,then in mix 2 I mix rudder to elevator (this gives you a TX "Vtail " mix)
Next you mix ail to pitch and then on another mix you mix pitch to ail ( this is the collective pitch and also the differential collective pitch for the roll axis . I don't use roll cyclic as the DCP (differential collective pitch ) will take care of the roll axis .
So here is a written simple approach to what Rudy and I are doing to control our model.
#1 both heads go up and down for collective pitch (altitude control )
#2 one head goes negative pitch while the other head goes positive ( differential collective pitch for ROLL axis control )
#3 both swash plates go forward and back at the same time (forward and back //// PITCH axis control )
#4 one side swash plate tilts back ,,,while the other side tilts forward (differential cyclic to control the YAW axis)

Now Vtolmans approach to a non scale, easy building and flying bird is a little easier to understand ,,but I have email talked with him and his mixes are somewhat a mess like mine.They have to be as you are flying two different birds on one .

O.K. the side job is not finished ,I got the kitchen back together enough for the lady to do Christmas and new yrs dinners ...so I have taken the next two weeks off from the side job because it is the holidays and my son from California is going to be here. He is not due here for another 4 hrs ,,So I think this early time in this thread would be a good time to introduce some charts and pix that I have found on the internet and have been given by different V-22 associated people around the country.These will maybe help those of you trying to figure out the control of this beast.
ENJOY AND MERRY CHRISTMAS TO ALL :D :cool:

#0
http://static.rcgroups.com/gallery/data/500/14579helicontrol1.gif
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#1
http://static.rcgroups.com/gallery/data/500/14579Osprey1.gif
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#2
http://static.rcgroups.com/gallery/data/500/14579Osprey2.gif
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#3
http://static.rcgroups.com/gallery/data/500/14579Osprey4.gif
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#4
http://static.rcgroups.com/gallery/data/500/14579Osprey4.gif
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#5
http://static.rcgroups.com/gallery/data/500/14579Osprey5.gif
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Just a break in the intense reading.

http://static.rcgroups.com/gallery/data/500/14579Osprey2topani.gif

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#6
http://static.rcgroups.com/gallery/data/500/14579v22tiltchart.jpg
#7

IMG]http://static.rcgroups.com/gallery/data/500/14579tiltchart.jpg[/IMG]




Another break and my first touch of the real thing ..along with part (3 of the 6 kids )of my other pride and joy ,,,my extended family
http://static.rcgroups.com/gallery/data/500/14579familyatv22museum-med.jpg

[v22chap]

O.K. here is a little txt of something I wrote to a guy about my last project. It might help and it also introduces you to where the idea came from.
Enjoy
Larry
This project started by me trying to help my 13 yr old son learn to fly R/C helis and also build some confidence in him self and his ideas.He saw the XV-15 in a small article and wanted us to try and build it. I "KNEW " it wouldn't work ,,but since he had came home from school with ideas and hand drawn plans for the last two weeks ,I decided to tell him his ideas were good and try my best to make it work.Well to make a long story short ,the first one worked really good as a hover test bed ,even though it was thrown together from different parts borrowed from different friends and different old crashed airplanes .He graduated from high school deciding to go to college to become an aeronautical engineer ,,wonder where he decided that from . To make another long story short ,he has just this year graduated with his masters degree in computer engineering and is going to start a job working for Northrop Grumman writing code for the militaries JUCAV (J-oint U-manned C-ombat A-aerial V-ehicle ) research program in California .
I on the other hand am not an engineer ,just a creative college maintenance man that is good with his hands.I build from what I see in my mind and what looks like it would work and not from thought out scientific calculated and drawn plans, which is probably why the transition is not working.I also usually use what I have available instead of buying new stuff.This winter I am drawing up some simple plans and running every thing thru a plug and chug plane calculator that I found and hopefully this will give me a better chance at the transition problem.I will give you what I know works and what I know don't work.It will be in simple bitmap drawings but I think it will help you understand where I have been and am going.I doubt that even if any one gets this thing to work that many people will want it.It is hard to build,program and maintain and the cost is really high.

This next version is going to have two highly modified Robbie Conquest mechanics in it ,with two O.S. .46 's for power.The wingspan of this one is going to be 50 inches ,a 9.5 cord ,with a 58.5" or so fuse I am still working on it.One 3 view that I am using has it at 58 and the model I am measuring is the 56 ". The small wingspan gives this bird about a 87 oz/sq in wingloading ,which is high for a model.I have been told that the wingloading problem is not a problem on the v22 because you are not taking off and slowing down to land which is where a standard plane has problems with the wingloading numbers.

I use a 3/4" aluminum tube to tie the two engine pods together.It also houses the 1/4" carbon fiber tail drive tube that connects the two gearboxes together to keep them in time.They have to be in time or one head will be going forward while the other may be trying to go side ways.

The wing ribs have oversized 3/4" holes cut thru them and this is the only bearing surfaces that the tube runs thru.I apply a light coat of silicone grease to the holes so it pivots a little easier .. You have to save weight any where you can.This also has an arm attached to it in the middle that is the pivot arm .I use an electric motor(280) thru a 2:1 gearbox then thru another worm and pinion gear setup turning a threaded rod for the tilt process.The whole tilt ,from 90 degrees up to 0 degs forward take only 6 seconds.This setup has to be done this way to hold the engine pods in place .With out the worm gear setup, it will creep forward in continuous hover conditions.

I use a 3 position micro switch system to do the tilt . The tilt motor is activated by my stunt switch moving to position #1 and this moves the nacelles to the 60 degree position stop switch within about 2 seconds.Then the 60 degree switch is mounted to a bellcrank which can be pulled back and eventually out of the way to complete the rest of the tilt process a little at a time. When the bellcrank is out of the way the tilt arm goes all the way to the 0 degree position (airplane mode) and hits another micro switch to shut off the tilt process and reset it to go back to heli mode.

More pixhttp://static.rcgroups.com/gallery/data/500/14579drive_train.gif
http://static.rcgroups.com/gallery/data/500/14579crossdrivesys.gif
http://static.rcgroups.com/gallery/data/500/14579v22drivetrain2gif.gif
http://static.rcgroups.com/gallery/data/500/14579v-22dimenfor2004proje.jpg

[rdresch]

Dang Larry, That really tells it all. Excellent post, great way to show how many forces interact during transition. To those of you who are a bit overwhelmed by all the talk of mixes etc. That used to be the only way to do it. Now however we have the TH2 which will simplify it once we figure out all we need it to do. This should eliminate most all the mixes and make it possible to use a much simpler radio system. Let the discussions begin>
Merry Christmas and a stable hover to all.
Doesn't Santa use VTOL?
Dear Santa, I know you use reindeer for thrust and magical dust for lift. Is the transition controlled by the sled or the reindeer?
Rudy

[StrBean]

The wingspan of this one is going to be 50 inches ,a 9.5 cord ,with a 58.5" or so fuse I am still working on it.One 3 view that I am using has it at 58 and the model I am measuring is the 56 ". The small wingspan gives this bird about a 87 oz/sq in wingloading ,which is high for a model.I have been told that the wingloading problem is not a problem on the v22 because you are not taking off and slowing down to land which is where a standard plane has problems with the wingloading numbers.

I can't make sense of your wing loading numbers. 50 in span x 9.5 in chord = 475 sq-in of wing area at 87 oz/sq-in you imply the model weights 475 x 87 = 41,325 oz or 2,582 lb. Obviously not what you ment. Anyhow, wing loading does matter for a tilt rotor, and it is directly related to transition. Too small a wing area will result in too high a stall speed and you won't be able to transition from helicopter mode to airplane mode. Very rough rule of thumb is probably about 80% of the wing area you'd want on a fixed wing airplane of the same weight will work for you tilt-rotor.

[v22chap]

StrBean
Yep ,,you're right ,,was a typo ,,should have been 87 oz/ sq.ft. as it was a 48 X9.5 wing on a 17 lb bird to start out with ,but grew as I built it and I changed the wing measurements from the copy of the email to what I actually made the wing so as not to mislead anyone . Now that you questioned the numbers ,,I went and actually measured the reamains of the wing and find it was actually 50 " X 10" chord. So the wing loading with a 20 lb bird is 88 oz/sq ft. which is still high ,,but seems to be able to become wingborne.
Your're also right that wingloading does matter....just not as much.. I was told by a retired V-22 engineer at the museum that the real one has some where over 100 (and I am not sure whether this would be lbs /sq ft or what ),,but the main thing is he said you can get by with a large wingloading if you are not rotating off the ground or slowing down to land on the ground or trying to do aerobatics with it.Which by the way ,,the real one has been put through a roll many times just to see what would happen if you got into that situation.
Larry

[rdresch]

at full payload and 50% fuel it has a wing loading of 90 Lbs per sq ft. That's a rock. It's glide ratio is 2 to 1. Glides like the shuttle. It is not capable of auto rotation. Which brings me to my problem. I was planning to put a one way bearing in the main shaft of each rotor pod. The design doesn't work. There is a slight clearance and the side loads from the shaft cause it to bind slightly. It is bad enough that I feel its just added weight that does nothing useful. I think now I will put the one way on the shaft between the rotor pods at the pulleys. If I lose the engine both rotors are still tied together and there is not much friction in the drive system. Redesign number 4
Rudy

[v22chap]

Rudy ,,sorry to hear about the rebuild ,,but that is the story of my last 16 yrs. :eek: :o ;) :rolleyes: I thought the real one could do autorotation ,,well at least a controlled crash ..hopefully walk away type.

[rdresch]

But at least you actually got yours flying. I dont even get to crash mine before rebuilding. Still I want it right, It'll be done when its done.
Check this out
http://www.g2mil.com/V-22safety.htm
Rudy

[v22chap]

yep ,,I have read several of these nay sayers and they have good points ,,but it don't stop the Marines from wanting it and wanting it bad.It actually is the Marines that demanded the blades be made smaller ,,so it would still fit on the present carrier decks ...the XV-15's have been flying for yrs with none of these problems .The XV-15 don't have to fold the blades and wings up like a horse fly so they can be stored on board ship.
As with every new technology comes problems and if we all gave up and didn't take some chances we would all still be driving horse and buggies around lighting camp fires and eating beef jerky because there are no refrigerators yet . ;) :rolleyes: :D

[rdresch]

agreed only posted it to show it wont really auto. I was wondering since the problem is the proplike blades will ours auto with twisted blades?
Rudy

[v22chap]

I really doubt that they will auto and if they do it will be a rough one.That is one other reason I went with two engines.. I have lost one engine while hovering and didn't hear it until I landed and tried to take off again and could hear the one good engine laboring to try and lift off.Which it will do ,but it is hard on the engine and clutch lining. :eek: :D

[StrBean]

Folks,

The V-22 will autorotate, it just does it at a higher rate of descent than say an OH-6. Autorotation capability is basically related to the rotor's disk loading (weight / sweep rotor disk area) and inertia. The V-22 is a high disk loading rotor (partly because of the folding requirement noted earlier).

As for the glide ratio of 2:1, where did you get that number? The data I've seen shows it be higher than that in airplane mode. But alas I don't have a copy of the data nor is it publically available on the internet.

Also with regards to wing loading I would think long and hard about having the wing loading so high. Pardon the math but:
Vstall = SQRT( Weight / (0.5 * rho * Wing Area * CLmax) ) or using the defintion of wing loading (Weight / Wing Area): Vstall = SQRT( Wing Loading / (0.5 * rho * CLmax) )

rho is the density of air not something you can control. So we see that stall speed then increases with wing loading and decreases with CLmax. CLmax is the maximum coefficient of lift (CL) the wing can generate and unfortunately going to smaller scale typically reduces the CLmax compared to a full-scale airplane. Assuming CLmax = 1.1 and is a constant is probably a pretty good estimate for design purposes.

The key point to understand for the current discussion is that those equations I listed above say that if you have the same wing loading as a full-scale airplane you'll stall at roughtly the same airspeed as a full-scale airplane. For the V-22 I think the stall speed is >125 knots, way to fast for model airplane IMHO. Look at what model jets do for wing loading but I think you need to get down to ~40 oz/sq-ft to make this work. Finding light solutions for the mechanics is key.

[foamkiller]

double post

[v22chap]

StrBean ,, Now I'm lost ;) :eek: :rolleyes: :D
I wish I could build one lighter,,I've been trying different ways for almost 17 yrs now and 20 lbs is a light as I can do it and is lighter by 4 lbs than any one elses that I know of.It isn't that I want the wingloading that high ,,but the only way I can see now to reduce it is to make the bird in a larger scale ,,and that would mean building a new house to build it in,,and that just ain't going to happen soon .I don't think my limiting factor right now is the 88 wingloading as I have flown the bird in airplane mode only with up to 68 oz/sq ft of wingloading and rotated off a grass run way and landed o.k. and think I could have carried more up ,,but ran out of weight to put in and the weather went to snow the next day and I couldn't go back out and try it again ...plus back then the bird was only 15 lbs ...but it didn't have all the stuff needed to tilt in it yet.

[rdresch]

StrBean.
I found the spec in a V22 web page, not official literature, so it could be wrong. Still a Cessna 177 has a wing loading of about 15lbs per sq ft. It has a glide ratio of about 15 to 1. Since the Osprey has a a wing loading 6 times higher that would be 2.5 to 1. That is with full useful load and 50% fuel. I did notice that there seem to be a lot vortice generators etc on the wing so it may be a little more efficient near stall speed whatever that is. Still, gliding engines out it is a rock.
Please note that on our model the wing loading is oz per sq ft, not lbs, so our wing loading is 1/16 that of the real bird. Though this is still extremely heavy. On my own model I am striving for around 50 oz per sq ft. Even this is heavy but the best I can do.
My model is turbine powered. By the time you add in the weight of engine and gear box 5 lbs. fuel 3 lbs. engine pods with gear reduction 3 lbs including servos, pulleys and belts 2.5 lbs. and cross shaft with drive 1 lb things get heavy quickly. I blew scale and added length and width to the wings. I am honestly considering a ballistic parachute instead of auto rotation or gliding in. If I lose the engine in transition mode it's done for.
Rudy

[rdresch]

StrBean
I love the internet. Thanks for your formula. Now if I could get a little more info from you maybe I could use it.
First, what do you use for a number for air density? I understand it is about 14,7 lbs per sq inch do I use 14.7 in the formula? Also on the wing loading, do I use weight in Lbs/wing area in sq inches or sq ft? I am trying to plug in the formula but can't seem to make it work. I need a answer in MPH.
Thanks Rudy

[StrBean]

14.7 lb/sq-ft is the pressure of air a sea level it's the same a 29.92 in of mercury on a barometer (a standard day). Density is related to pressure and it's 0.002377 slug/cu-ft [1.225 kg/cu-m]. If you aren't familiar with a slug, it's measure of mass in conventional units. Don't be confused, kg is a mass unit and lb is a force unit although we use them in everyday life as if they were both either mass or force (depending on your viewpoint)

The equation I gave you gives the answer speed in feet/sec or meter/sec depeding on the unit system you use. To convert from feet/sec to mph multiply the answer by (3600/5280) - 3600 sec in a hour divided by 5280 ft in a mile. (Speed in mph is roughly 2/3 speed in feet/second)

You need to use the wing loading in lb/sq-ft or N/m^2. Your are correct about the wing loading being discussed of ~90 oz/sq-ft being roughly 1/16 that of the full-scale V-22: 5.625 lb/sq-ft
So the model V-stall will be approx.:
Vstall = SQRT (5.626 / (0.002377 * 1.1)) = 46.4 fps = 31 mph which is better than I was thinking than when I wrote the first reply. I had gotten confused by the original post's wing loading units.

[rdresch]

Thanks StrgBean for all the help. I've got it now. What I find incredibly interesting is that lowering the wing loading from 90oz per sq ft to 60 oz per sq ft only decreases stall 3 mph.
Thanks again Rudy

[v22chap]

StrgBean that is some good info.. can't use the formula ,,but knowing the stall speed difference gives me some faith in my bird.
Thanks
Larry

[v22chap]

Happy New Year to all and may this year be greater for you and your families and hobby than last.
Larry

[rdresch]

Happy new year to all!! May God give us the strength to overcome our challenges and the wisdom to enjoy our daily gifts.
Rudy

[v22chap]

Rudy
I got a set up with the TH-2 were I can turn off the rudder and elevator ..in case Joe can't do it for us. I am using the 4 servo swash setup (but using only 3 servos) in your config with the A and P front to back and the E off to the side.I switch the Ail and Elev. inputs . Put the DCP constant to controlled by the elevator not channel 5 .
Then in the TX mix Rud to AUX 2 and take the ail input to TH-2 from this Aux mix .Then mix Elev. to Aux 3 and take the Elev input to the TH-2 from here ..this allows you to put these inputs for rud and elev. to the TH-2 on the stunt switch so they can be shut off .My TX will center them as they are shut off.
At least it looks like it will work on the bench ,,I need to make a mock up of the system ,so I can see the actual swash movement ,,not just try to picture it in my head from patches of tape on servo wheels ...if you know where I am coming from . ;) :rolleyes: :D
The rest of the flap and tilt switch can still be done as I would originally on one more mix ...so you still could do it with your 3 mixes.

We'll see what Joe can do for us though ,,before I build it this way.
Got my new years 1st flight in even though it rained light rain all day yesterday.. hovered several battery packs out in the garage with my T-Rex ...better than not flying at all on new years day... bad start to the year you know,, if you don't fly that day..... :eek: ;) :p :rolleyes: :cool:
Larry

[rdresch]

Larry
Sounds reasonable to me. Hopefully Joe will be able to incorpoate these into the th2 so those of use with a transmitter not as flexable as a JR 10 can do the same.
Rudy

[rdresch]

I have been working with Larry aka V22chap and Joe Orlando TH-2 designer on the requirements of a special TH-2 for tilt wing. Features we are working on include
1 a new swashplate type so you can take 2 zooms or other helis of any size and tie them together by the booms and retain yaw controll thru the elev axis.

2 Variable input through channel 5 with user adjustable setpoint that will controll when TH-2 switches from Heli to airplane.

3 When in airplane mode ail and rudder will be switched with each other, this way transmitter functions remein the same: ie a rudder input will controll the yaw axis no matter what mode you are in.

4 Seperate gain inputs for airplane and heli. This way one could turn off any axis desired when transitioning to airplane mode, or reduce its range from 0 to 100%
Input Please.

Rudy

[rdresch]

I've been kind of sidelined working on a T Rex. I need some parts machined to finish up the drive system, but machinist has no time, Holidays and all. I got so tired of always waiting for some stupid little part that I broke down and bought a small benchtop lathe mill combo from Grizzly Products. Should arrive next week. Now all I need is 5K worth of tooling and someone to show me how to use it! Just Kidding.
Rudy

[v22chap]

all I need is 5K worth of tooling and someone to show me how to use it!
:D :D :D :D :D :D
Been there done that .. let me know how you like the Grizzly
I have a little old hobbymat that is on its last leg ,,come to think about it ,,that is all it had when I got it.

[rdresch]

I am no machinist!! still after trying to use a poor drill press and build parts for my V22 Osprey project something had to be done. Finally broke down and bought a small combo lathe mill from Grizzly products. How did I ever do without this! Yes it's a lot of money, about 1500 with extra tooling I ordered. Still I spent over $500 on outside machinists over the past 3 months. Now I get to change my mind and prototype #7 is just a couple of hours in the garage. Will post a few pictures of my progress on the drive system later today.
Rudy

[v22chap]

Can hardly wait to see the product of your new lathe. I have been trying to get up some pix of my new gearbox ,,so as to put a little bump into this thread again ,,but have just been to busy.

As a little update on my project .......I did find a company in England that is doing my special gears. It is going to cost ,,what with the dollar difference ,,but atleast they didn't laugh me off the phone when I said I only needed two of each gear.

Thanks to HPC gears of England for their wonderful support of a small time hobbist in his pursuit of special size gears.
Larry

[askman]

I am no machinist!! still after trying to use a poor drill press and build parts for my V22 Osprey project something had to be done. Finally broke down and bought a small combo lathe mill from Grizzly products. How did I ever do without this! Yes it's a lot of money, about 1500 with extra tooling I ordered. Still I spent over $500 on outside machinists over the past 3 months. Now I get to change my mind and prototype #7 is just a couple of hours in the garage. Will post a few pictures of my progress on the drive system later today.
Rudy


there is never enough tooling. or tools. or machinery. :) I started out with combo, before deciding to go separate. I prefer having separate mill and lathe, then CNC mill, then CNC router. never ending tools...

[rdresch]

I wish I had the room for bigger machines. A friend just closed his shop I could have had a cnc mill and a nice lathe with tooling for about $2500. Still this does most of what I need. Will post pictures soon
Rudy

[rdresch]

I finally got around to taking a few pictures of the wing support and power transmission set up on my V22 Ospey. Still much to do. Some if it shuold have been built in a single piece, but I didn't know some of the dimensions at the time. So, it was build a section then build another section then weld them together.
Rudy

[v22chap]

Rudy ,,very impressive. Do you alum.weld too ?? That looks like you are going to be able to ride in that baby. ;) :D
Keep up the good work and keep the pix coming.
Larry

[rdresch]

Ok I need help.I have finished the tilt arm for the V22. I would like to connect a servo to a jack shaft. I need a source for small jackshafts, any ideas.
Rudy

[Scott J]

Very impressive! Stock Drive Products may have what you need.
http://www.sdp-si.com/
Hope this helps.

Scott

[rdresch]

Thanks Scott, but I tried them first. Found nothing that I could use.
Searching
Rudy

[v22chap]

Rudy
Let me check where I got mine from ,,I think I got it from Boston gear ,,but not sure.When I get home ,,I will look for the bill ,,hope I keep it.


Larry

[v22chap]

Rudy ,,I can't find the bill as it was 5 yrs ago when I bought this 6 ' piece .


Here is where I think I got mine :
lead screw link (http://www.mcmaster.com/)



Here is another good company
leadscrew (http://www.huco.com/products.asp?cat=382)
They have the cheap style (brass nuts ) or the precision ones that are more expensive too and in small dia. sizes.

Hope this helps some
Larry

[rdresch]

Thanks all, I looked through macmaster carr like 5 times and didnt find what I was looking for. But then again I didn't know it was called a leadscrew. I think I will need about a 1 -1/2 of travel with a 1/4-8 that would be 3 turns on the servo. I found a site on the internet that shows how to modify a servo. Larry How did you do it? Then there is the robot servos from Servo city with a 5 to 1 gear reduction. 1000 inch oz of torque. Any thoughts on this.
Thanks Rudy

[v22chap]

Rudy ,,you don't want to know how I did it ,,,as ususal it is the hard way.

I have tried the modified servo deal and it didn't have enough holding power. These large diameter rotors and the vibration can move a lot of torque holding power around and the last thing you need is the tilt going back and forth on its own . Now mind you this was back when the largest servo was 100 oz. ...now with the larger servos it might be different.


So I went about the same route the real one did.
I use a 3:1 gear reduced 280 electric motor with micro limit switch to stop /start the process. I also use a 2.5:1 worm and spur gear reduction just before the lead screw ,,,as the torque of those 42 " rotors moving back and forth will make the 3:1 gear reduction unit by itself creep forward ,in continuous hover ,,until you are in 45 degree forward rotor tilt and haven't even hit the tilt switch yet.
Hope this helps some
Larry

[Tuner]

www.emachineshop.com

I have yet to try them but check the site out.

Scott

[rdresch]

Tuner, I put that on my remember list could be handy
Larry time to stop and think, I think a shallow acme thread screw. Time to experiment
Thanks Rudy

[v22chap]

Rudy
What I used was the precision modified acme,,but I don't remember paying that much for it. I think the mininature precision would probably do the trick and might have less slop to it..the larger thread has just a little blacklash to it with just a brass nut ,,and we sure don't have the room for ball bearing nuts.
I started with just plan threaded rod ,but that didn't move things fast enough ,,had to go to the rod that lets you choose turns per inch.
Larry

[BQuick]

I'm planning on trying my hand at an osprey. Where do you guys get the reverse pitch props?

- Brad

[v22chap]

Hi Brad
I myself am making them from wood heli blades as I need 42 " and they don't make only up to about 22 " in airplane props that are reversed . I think Rudy is trying to make some out of carbon fiber .
I think top flite is the company that makes props that big with tractor and pusher types.
Good luck on your project and keep us all posted
Larry

[rdresch]

Brad how big is your planned project? Makes a big difference as to what is available. You can always start with normal heli blades and flip them to give you R&L. That is as long as they are symetrical. Scale looking blades (look like a prop) you have to make. These will give more top speed in airplane mode, but take different gearing. It takes a bunch more power to spin that much pitch and diameter. Larry I know you are committed to the twisted props, I am just not sure yet.
Rudy

[v22chap]

Rudy ...
you are committed to the twisted props
No ,,that is I should be committed :D :D :D
You're right,, for just hovering and a little 60 degree flight you can just use regular symetrical helicopter blades. But I am 99.9 % sure that to do forward airplane flight with our heavy birds ,,,you need the twisted blades.I don't have any hard evidence for that ,,but that is what I have been told by a retired V-22 engineer at the Pensylvania helicopter museum.I also have never been able to maintain forward flight in the 60 degree mode with the heli blades...but that might also be due to the fact of me getting more at home with the bird in that position now that I have been there a lot of times.


Now with that said ,,the first tilt rotor ,,, Bell xv-3 ,,used bell 47 flat blades and it made the full transition,,,but it also used a two speed manual shift transmission to lower the gearing so they could really pull large amounts of pitch and also the bird weighed in at a lot less than ours do.
Speaking of pulling large amounts of pitch ,,If I remember right one of the mechanics at Pax River told me the real v-22 still pulls around 47 degrees ,,plus the 47 degrees that are in the twist of the blade,but I am sure this is for the speed factor that they wanted not just for conversion.

So I am not going to stick my neck out here and say you have to have airplane props.What I am saying is if you are starting out ,,it might be nice to size the machine to what is out there as far as props... Kingsley already proved that small machines can make the 60 degree transition and he didn't use the largest props that were out there.
Good luck and have fun. ;) :D
Larry

[rdresch]

Larry, The size is exactly what has me concerned. With scale size blades that are twisted I would need huge amounts of torque to turn. My ship is set to turn 1800 rpm. I would have to regear to turn slower rpm. I don't know how much. That or make the blades shorter. Anyway I still have an experiment in mind to test the speed attainable with heli blades. I am not throwing my twisted blade mold just yet.
Rudy

[v22chap]

Rudy ,,I would say you could just shorten the blades ,,as when I put my first set of twisted blades to the test I bolted them on my VR 46 (which were 520mm blades on a 535mm blade bird ) and I had to bring my pitch curve way down along with my throttle curve.I had all sorts of lift with no engine lug at all.At low stick I had -6 (measured on the tips) ,half stick +2 and top end was +6 and it flew,, looped and rolled just like before.I did notice some pitch up as you slowed down in FF or pulled elevator to make a sharp turn.

[BQuick]

Thanks for the responses, guys.

I'm probably looking for something in the 11 to 12" range for prop sizes. I have made my own heli blades for my homebuilt heli, but I doubt they are nearly as efficent as molded props where the pitch changes from root to tip. I'm thinking of using two triple stator CD-ROM type motors.

Anyone know where to buy stock props with reverse pitch?

Thanks.

- Brad

[v22chap]

Brad
Master airscrew makes some in 9X7 and 14X7 also in the 16X10 tractor and pusher in plastic 3 blades .
3 bladed 14X7 (http://www.masterairscrew.com/GoCart/itemlist.asp?RootID=7016)
Zinger props make tractor and pusher in 2 blade in a very wide range up to 14 "
Zinger pusher (http://www.zingerpropeller.com/Pusher.htm)
Zinger tractor woods (http://www.zingerpropeller.com/Tractor.htm)
zinger 3 &4 bladed wood props (home page) (http://www.zingerpropeller.com/Products.htm)
Hope this helps some
Larry

[BQuick]

Thanks again, guys.

I just ordered a set of the Master Airscrew 14 x 7 3-blade's. They're a little pricey, but they'll look a little more scale than 2 bladers.

I plan on having some of the wing tilt with the motors so that I can use the same controls for ailerons in forward flight.

I'll let you know when I get a little further along.

- Brad

[v22chap]

Great ,, sounds like a good idea having part of the wing tilt with the pods. Good luck and keep us posted on the progress ,,,good / bad or any where in between :D
Lary

[rdresch]

I thought it was about time for a update! Progress is slow, but issues are being resolved. There is a clamp that ties both 1 inch pods together. it transfers torque from the servo to allow the pods to rotate together. I have finally got it right. Inside the clamp is the final timing pulley. The mill really came in handy. The tubes are 1inch by .083 aluminum and one pound of weight. I may order some 1 inch carbon fibre pieces that will cut that in half. I am just not sure they would be stiff enough. They are .043 wall. See attached pictures. The servo will be a hitec 340 oz torque with 5 to 1 gearing. However I am using the gear part only for the remote pots. The servo is modified for 360 degrees and I will attach a lead screw directly to the servo output. That screw needs 5 turns to give 1 inch travel. Still waiting for servo
Rudy

[v22chap]

Rudy ,,that is a unique idea on the clamp for tilt control of both pods.And yes you will need some heavy duty tubes that go out to the pods as there is still a lot of load ,,even without the motor being out there like mine.
Should work fine.Are you maybe going to have some tightening idlers for the timing belts?? as they will probably loosen up some after a few runs.
Keep the pix and work coming
Larry

[rdresch]

Robbe has just released a new flight stabilization system for heli's that is different. Contains a 3 axis gyro and a ground reference eye that works like a mouse. That gives ground reference. I don't know how well it works, but could be interesting.
http://at.robbe-online.net/rims_at....3e0dc1460688em.
Rudy

[v22chap]

Yep ,I just saw that in another forum ,,,looks like it might be of great use to us VTOL guys... will have to see if we can get more info and maybe some "Sample " items of it to test out on our VTOL's. ;) :D
Larry

[rdresch]

Yes, I only worry about it being compatible with the TH-2. I am not giving up my TH-2 for anything. I had a few problems when trying to interface gyros with the copilot. Servos would jitter. It was fine without the gyros. That was in the raptor for 3 blade rotor tests. Since this already has gyros included that should not be a problem. It would have to be mounted before the TH-2, so since it is sending a signal to the servos I don't think TH-2 will have a problem with it. Sure seems like it will eliminate some of the issues that had me concerned with the Co-Pilot. The field I fly at has a 5 ft berm near the helipads with 40 ft trees very near.
Rudy

[v22chap]

The new copilot is not suppose to have to many limiting factors ,,but this may be the way to go ,,I was suppose to have a copilot coming to try ,,but it has been a month now and I have not seen any ,,so I may have to look into this Robbe deal also.
Maybe Joe will chime in here soon and know what we need to know about it interfacing with the TH-2
Thanks for sharing
Larry

[rdresch]

The only advantage of the new system that I see is it can be used with ccpm. It also has a v sensor so it will bail you out if inverted. I believe it rolls you upright. You need to use their receiver which limits you to 8 channels. The old system which I have uses the same sensors, so they both have limits of IR horizon sensing. If my field wasn't so obstructed on one side I am sure it would work. Now to learn what the limitations of the robbe system is.
Rudy

[v22chap]

Ya ,,the 8 channels was going to be a tough one. This opens us up to using 10 again.

[v22chap]

Rudy ,,your link didn't work ,,so I just went to Robbe site ,,but I think maybe I was looking at a different unit ,,will PM you with what I had looked at to make sure.

[rdresch]

wierd, doesn't work for me either. Go to the Robbe site -products-new items
It's called Heli command 3A. It is not listed under gyro's. Your bird should arrive Today. Let me know what shape it is in.
Rudy

[v22chap]

yep the heli command 3 A is the one I saw on the site ,,but saw another type on the other thread. It was more the normal copilot deal with out a cover,,both from Robbe
Larry

[rdresch]

Yes, the one that is similar to co-pilot has all the limitations of co-pilot. It is also more expensive. I hear the quality is good though. Still it is the new one I will keep a eye on. Sent them a email for more info. I am trying to determinr if the output signal is compatiable with TH-2.
Rudy

[v22chap]

Good luck I sent an email to find out if they had a place to download more info or the manual from and they sent me an email prasing the product more ,,but no help what so ever.But if you get the right person ,and if they hear from enough of us ,they might just be able to answer the but question.
Larry

[rdresch]

Finally got a little work done. Tilt mechanics are done. I used the hitec robot servo. It is a beast. At 4.8 volts I can't budge the mechanics, though you can run it at 7.2volts. I would have loved to use a worm drive but room was a problem. I need to see how much of a draw this will be. Ultimately I will put a generator on the Osprey anyway.

[v22chap]

Looks like it should have enough to do the job.Those new gearbox's for servo's are great ...
I just had a another set back on my bird. The gears I ordered from England came yesterday ,,but only one set. I checked to make sure the last fax to them said 2 sets of bevel gears and it did ,I faxed them yesterday and still have no reply from them,,,lots of good one set is going to do me ,,,I may end up having to redesign the whole thing to use smaller bevels and a short shaft and pinion ,,which I didn't want to do. :( :o :mad:

[rdresch]

Time for a build update.
Good
I changed out the aluminum wing tubes for carbon fibre. I lost over a pound of weight and it's stiffer.
Bad
I am at 15lbs 11oz.This includes Turbine and inter-stage with gearbox and all support equipt.. All turbine mounts and pulleys with belts. Includes Tilt mechanics with servo also rotor pods and servos with main shaft and swash.
Heads with blades.
Not included
Fuselage and wing, fuel and servos for wing, wiring.
The most I can see cutting is 1 lb. And that will take days of machining. That means I am looking at 25 lbs complete and not the 20 I was hoping for. Looking for a large helium balloon.
Rudy

[v22chap]

rudy ..like I said in another thread ,,we all tend to build like we did for a normal plane ,,,to servive a crash. look real close and you will start to see more that can come off and it still fly.After the first few crashes ,,you will be able to see the places easier.I know that is not helpfull ,,but it was the only way I was able to find them too.

[rdresch]

Larry,
What is happening with your gears? I got a little more info on Robbe Heli command auto pilot. The eye only works to a altitude or 10 ft, useless for us.
Still this technology is moving rapidly, so hopefully soon there will be a solution that is practical for all. Spartan RC has the 2000i which works with the co-pilot sensor and will soon release a accelerometer unit to use instead of IR sensors. This may work better for us. I will e-mail them to get more info but it looks good. Has many feature, check it out. http://www.spartanrc.com/products/ap2000i/ap2000i.htm
Rudy

[flyhigh555]

Cool work rdresch. I'm looking forward to seeing this bird fly!

[v22chap]

Rudy,, I can't get HPC to return my faxes ,,I guess I will have to break down and call them .Did I maybe get ripped by them ...probably ,,my luck :rolleyes: :cool:
The 2000i sounds like it might be the way to go. Let me know what you find out ,,,it also is reasonable in the price range also.Not like the FMA .
Thanks
Larry

[rdresch]

Just a quick update on my V22. Decided I need to cut some weight. So far I have spent over 20 hours of drilling, milling, and filing. End result 4oz. I also decided to change the tilt mechanics. I am installing a acme precision thread to a servo. It's almost done. I am waiting in a adapter from servo city. This should also lose about 3 or 4 oz. That and the servo power requirements had me concerned. Without the screw jack that servo is holing at high power. There is a lot of force against it. It's not a lot of weight, still it is 8 oz of fuel I can carry. I'll post some pictures Monday or Tuesday when the part comes in. Larry, whats the story on the gears. I am afraid to ask.
Rudy

[v22chap]

Rudy
Yep weigh can really be a killer on these things and then also the battery time .This is why I use micro switches and the worm gear set up so the servo stays off until I command it to do something and the worm gear holds all the torque coming against it.
The gear people just got back to me Fri. before I left work .I noticed the secretary had a note on my inbox to call them back ,,but I didn't get any one ,,so they must have left for the weekend.
I am just about ready to do this another way that would use stock gears...but I would also add about a pound of weight ,,,soooooo I really want the gears.
Larry

[Eibo Morakinaga]

all I have to say is WOW.

[mrobbins]

interesting thread. You guys got any hair left working this V-22 out?
For your prop problem look at this site.
http://www.warbirdpropdrives.com/19401.html
It look like the way you may have to approch the problem

Mike

[rdresch]

Those constant speed props are so cool. I wish I could use one. The V22 uses cyclic control on the rotor hubs in heli mode. Also my rotor diameter is 48 inches with a 3 blade rotor as per scale. You are definataly right about losing the hair thing, but I just blame it on the wife.
Rudy

[v22chap]

Yep the hair is going fast ,,, :D
Thanks for sharing the info Mike ,,it might help the smaller VTOl guys ...but like Rudy my rotor dia is 42 " and I too have to use cyclic to control hover.
Larry

[rdresch]

Good news, I just heard from Joe, he is well. He had a computer crash and that's why we haven't heard from him for a while. VTOL TH-2 is not done yet. Joe is on some higher priority projects for the moment. Must make a living. I hope everyone understands that this VTOL TH-2 is of appeal to a limited group. Still Joe has a speacial love for this sort of thing and when he's finished with it it will solve many issues for all of us. Thanks Joe!
Rudy

[v22chap]

Yep ,,I for one appreciate Joe and the work he is doing for the hobby... hope every thing is going fine for him .. I know how life can sneak up on ya some times.I am in no rush for my unit as the gears are screwing me now any how...looks like next yr before I get mine in the air again.
And yes Rudy ,,you don't want to ask about the gears ,,I am so mad I could spit nails right now. :mad: :censored: Maybe later.
Thank Joe
Larry

[Tuner]

Thought you might want to see this link a little off the specific topic.
http://www.gizmag.com/go/5337/

Scott

[rdresch]

Thanks Scott, some new pictures that are helpfull.
Rudy

[v22chap]

Hey ,,great pix ,,and some other great VTOL prospects
;) :D
Thanks for sharing

[TMorita]

Rudy ,,you don't want to know how I did it ,,,as ususal it is the hard way.

I have tried the modified servo deal and it didn't have enough holding power.
...
Larry

Have you looked at these?

http://www.servocity.com/html/robotzone_servos.html

Toshi

[v22chap]

Toshi
Yep ,,I have one ,,but have not had a chance to try it.I don't believe it will still work as good as the worm /spur gear deal as the torque of the 42 " twin rotors pulling on my older straight gear reduction unit I had was the one that would creep forward in 4 or 5 minutes. You need the worm /spur gear to stop the torque.This new servo gearing setup wouldn't creep forward ,,but I am afraid it would be constantly using battery power up to stay in the orginal position and then you would have to carry bigger batteries ,,,,, more weight . Time will tell.
Thanks for bringing it up though. :D
Larry

[flyingphil202]

Let me know when you finish it, cant wait to see it fly (if you do).

[rdresch]

I just tried it both ways. The servo city gearbox with the large hitec servo will definataly hold , but it will draw current constantaly. It all depends on the size of the plane. You need a larger plane to handle the size and weight. I redid mine with a screw jack. This actually ends up lighter and stronger and uses very little current when not in motion. It also moves much slower and is more scale in appearance. I will post pictures of the new setup tommorro. Very simple. The only drawback here is the push pull loads go into the servo. So far this seems no problem, but a thrust bearing arrangement may be needed eventually.
Rudy

[Tuner]

I am still in works with GWS to get a Worm Drive Servo produced that I or they will resell. I hope these will work for other VTOL projects.

In the end this is the best method especialy if you are only tilting for transition and not control I would not do it any other way at all KISS.

In the end a geared system is not optimal if you intend on having any signifigant holding torque requirements over a longer period of time.

Scott

[Tumbler]

Started an Osprey-like project I thought you guys may want to see. Here is my XV-15 which was what led to the Osprey.

[v22chap]

Tumbler ,,welcome to the form on VTOL's and to the continual quest for true conversion.
You have a great looking start on the XV-15 and it is looking outstanding . Great idea on the balsa skelton/fanfold covered ... what power plant / guidance system are you going to use ???
Keep us updated and keep the great pix coming :D
Larry

[MustangAce17]

great looking vtol uve go there! i just started workin on mine again

[Tumbler]

Tumbler ,,welcome to the form on VTOL's and to the continual quest for true conversion.
You have a great looking start on the XV-15 and it is looking outstanding . Great idea on the balsa skelton/fanfold covered ... what power plant / guidance system are you going to use ???
Keep us updated and keep the great pix coming :D
Larry

Thanks Larry,

I am planning on canobolizing 2 micro helis with 20" rotor spans for the project. I made sure the main gear will fit inside the semi-scale motor housings I will eventually make. I want to make sure I could keep the weight within reason before I order the mechanics. Also, I am also trying to decide whether to go with fixed pitch or collective. Fixed pitch is simpler, however I would not have the option of counter rotating rotors and would therefore have to counteract the yaw torque by using opposite elevator cyclic. If I use collective, I have the option of counterrotating blades but with CCPM mixing its an additonal 2 servos on each side, one of which is not really needed(aileron is controlled by motors not by cyclic). Might just be more of a hassel.

I have planned to make the heli mechanics easily removable and interchangeable so I can always change them out. To start I am using the stock brushed motors and will use them on a 3 cell lipo until they burn out and then find a brushless hop up for them.

We shall see how she progresses!

[v22chap]

Sounds like you have it pretty well mapped out .It has been done with out collective ,,but they used a tail rotor to control the yaw ,,and not sure they tried to do it with the differentail cyclic,,,but I think it could be done as I did an airplane prop only ,,with tilting motors and had no cyclic at all or tail rotor and the yaw controlled fairly well.I know that cyclic yaw control with counter rotation works really well and would say use that ,,but the weigh savings is the thing you always need to watch ,,so I would suggest you try the non collective first and see how it performs.

[Tumbler]

Sounds like you have it pretty well mapped out .It has been done with out collective ,,but they used a tail rotor to control the yaw ,,and not sure they tried to do it with the differentail cyclic,,,but I think it could be done as I did an airplane prop only ,,with tilting motors and had no cyclic at all or tail rotor and the yaw controlled fairly well.I know that cyclic yaw control with counter rotation works really well and would say use that ,,but the weigh savings is the thing you always need to watch ,,so I would suggest you try the non collective first and see how it performs.

Larry,

You remember this one right? This is fixed pictch also. You can see the opposite elevator cyclic. This was 4 yrs ago before the lithium batteries and brushless motor craze. The technology is so much better now I decided to take another stab at it.

I would love to find large plastic propellers. hmmmm.

Brian

[v22chap]

O.K. Brian ,,that is who this is ,,,those were hyperflies as I remember,,,I 'll have to go to my website to see as I think I still have yours up on my site. I did forget that it was non collective,,was thinking they were concept ep's
Good luck and keep us posted on the progress,,what with the lighter batteries and the great motor /esc setups we have now it should work really good.
Larry

[Tumbler]

Do you think a pitch gyro helps in transition. I didn't use one on my last design as it was not needed to hover. Wonder if it would help keep the nose down during transition. What do you think?

Brian