XV-15 Build(Predecessor to the V-22 Osprey)

[Tumbler]

I started this a few days ago. It is a scale model of the XV-15 which was the predecessor to the v-22 OSprey. I Printed 3-views for both models and thought this one was a lttle sleeker looking.

I am planning on canobolizing 2 micro helis with 20" rotor spans for the project. I wanted 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.

Anyway, hers a pic of the real xv-15 and some of the build.

[Tumbler]

Here is the wing with carbon rod which will rotate with the heli mechanics. Made of depron and balsa.

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Fuse. Again built with balsa and depron.

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Nose cone. 1.4ozs before, .5 ozs after hollowing out.

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Total weight so far is 5.5ozs.

[gear-head]

Thats pretty cool stuff, can't wait to see it finished!

[Osprey WannaB]

Exactly... this is like totaly wicked... i like ur ideas for the body... great work... keep it up....
i'm also workin on my own v-22 and i am trying to make a helicopter rotor head ect. so i can fly it just like a chopper or a plane.. i think my idea will be gud if i can get it to work... but i have a small budget as i am only 15 yrs old... If I had the money i would just buy two 4 chanel heli's and hook them on the wings :D
Regards,
Jamie

[Tumbler]

Exactly... this is like totaly wicked... i like ur ideas for the body... great work... keep it up....
i'm also workin on my own v-22 and i am trying to make a helicopter rotor head ect. so i can fly it just like a chopper or a plane.. i think my idea will be gud if i can get it to work... but i have a small budget as i am only 15 yrs old... If I had the money i would just buy two 4 chanel heli's and hook them on the wings :D
Regards,
Jamie


Thanks guys!

Jaime........i understand the limitations of having a limited budget. I am 29 and have been doing RC since I was 12. I remember even at around your age taking radio control cars apart and using the parts to make a VTOL. Some day you will have a job and money and be able to buy all the crap you want for RC....haha. I did actually buy two 4 channel micro helis like you were sayig. Balsa Products had the airframes for $40 each, which wasn't too bad. I noticed though that the main shaft is kind of short making it very top heavy once it ismounted. I would like it to be mounted on the CG of the hel mechanics but doesn't look like thats possible. Hmmm I modified it and moved the motor to underneath the spure gear, but doesn't help too much.

Brian

[MustangAce17]

ive decided to scrap my project after repetitive tries at different set-ups and flight tests. Ive only been able to stay airborne for a half second and revd the motors twice while there but i don't think i have the stability,skills needed to fly(never flown a fixed pitch heli) and equipment and money need(gyros) to do this sucessfully yet. I really hate to give up but i might try something else.

[Tumbler]

ive decided to scrap my project after repetitive tries at different set-ups and flight tests. Ive only been able to stay airborne for a half second and revd the motors twice while there but i don't think i have the stability,skills needed to fly(never flown a fixed pitch heli) and equipment and money need(gyros) to do this sucessfully yet. I really hate to give up but i might try something else.



aahhhh you can't give up. I will tell you, without a roll and yaw gyro your chances of success are limited. You don't need a pitch gyro though. I can hover a heli and airplane pretty easily which helps A LOT, but without gyros I wouldn't be able to hover a VTOL.

This was my test bed from 4 years ago. The downfall of using fixed pitch heli mechanics is that there are no counter rotating blades available, so i have to counteract the adverse yaw with opposite pitch as you can see in the pic. I am sure I lose power by doing this.

Brian

[v22chap]

Brian,, glad you started another build thread on your project as it looks to be very interesting and should help encourage other VTOL builders.
Did you go with the non collective or collective idea?
Larry

[Tumbler]

Brian,, glad you started another build thread on your project as it looks to be very interesting and should help encourage other VTOL builders.
Did you go with the non collective or collective idea?
Larry


I went with non-collective. Just wish I could find counterrotating blades and I'd be set.


Brian

[Tuner]

Ahh Found it

http://www.spectrolutions.com/

Click on Online store and he is selling the blades.

Scott

[v22chap]

Scott ,,great find ,,isn't the internet a great tool :) :cool:
Thanks for sharing ,,,now Brian get to work :D
Do I remember you saying these had a rotor diameter of 22",, HMMMM ,,I may have to change my scale size ;) :) :D

[Osprey WannaB]

Brain i love that picture... it was wat got me in to thinkng about a Rc VTOL. I did'nt realise it was ur's though.. anyways, great work and keep it up.. keep us posted, :D
Jamie

[MustangAce17]

brian,im big into 3d so ive hovered quite a few airplanes in my 4 years in this hobby so far, hellis ive only flown on the sim but i can hover them inverted. Im going to try my Optic 6 radio with expo and then shorten the motor stick lengths and see how that helps

[Tumbler]

Ahh Found it

http://www.spectrolutions.com/

Click on Online store and he is selling the blades.

Scott


Tuner,

I sent him an email but looks like these are the blades for the small Dragonflyer, not the bif X-Pro. Thanks, for the tip, we'll see what happens.

Thanks,

Brian

[Tumbler]

Brain i love that picture... it was wat got me in to thinkng about a Rc VTOL. I did'nt realise it was ur's though.. anyways, great work and keep it up.. keep us posted, :D
Jamie


Oh no, don't hold me responsible hahaha. No, seriously, nice to see otheres give it a try.

Larry,

Yes, I scaled the deisgn down to 22" rotor diameter so I could fit the main spur gear in the motor housing....using 20" blades though. I am close to being read to install the mechanics, but having trouble because once the blades are the right height above the wing, the machanics will be top heavy when mounted on the main spar. I really need a longer main shaft, but don't have a lathe to make one. hmmmm

Brian

[v22chap]

Brian
Can you maybe find some drill rod the right size diameter and then just be able to cut it to length ??? What size is the main shaft.
Larry

[Tumbler]

Larry,

Ok I found this site. hmmm. I'll have to go over my buddy's and borrow his micrometer.

Thanks!

Should have the airframe done tomorrow and take some pics

Brian

[Tumbler]

Still lots of filling and sanding to do but the airframe is just about ready to start mounting mechanics and electronics.

[MustangAce17]

Brian, what an awesome job! you are a balsa and depron artist! this x-15 is sweet! im still workin on my vtol but the counter rotaing 10 4x5s made a world of difference, ive just got to get the landing gear to stay stable and not bend.

[Tumbler]

Thnaks man! I have built a lot of them. I have trouble keeping them light though. This one is as light as it can possibly be and is still 9.5 ozs so far. thats with the carbon wing tube and all the wiring in the wing which was almost 3ozs alone!!!

Do you have a link to a thread with your vtol design?

[MustangAce17]

http://www.rcgroups.com/forums/showthread.php?t=471820

[v22chap]

Great looking job Brian ... hope you get the mechanics problem figured out as that is going to be a great bird. :D
Larry

[Tumbler]

Thanks Larry!

I ordered the drill rod today and my buddy is a machinist and going to drill the little 1/32 holes through the side for the cotter pins to hold it all together. I found counter-rotating blades Its all coming together! Only think I am worried about is weight, as its creeping up on me. Can always fix that with MORE POWER, ARH, ARH ARH!

I have been looking at Jon Pohls's xv-15 on your site. Did that thing ever fly. That thing is sweet!!!

Brian

[v22chap]

Brian
Yep the weight always climbs ,,, ;)
I always thought that put a big enough engine on a brick and it would fly too ,,but atlast I have found out that just isn't true ... :rolleyes: :eek:

Jon's XV-15 has never been flown ,,nor have the blades ever been tested to see if they would hold the weight of that thing. He lives 2 .5 hrs away from me and he wanted me to test fly it ...... :eek: I said if and when he gets a test rig built to hold it I would ,,but I am not going to fly ... nor could I even think of trying to hover it without some kind of protection for the bird. That is over a 1/4 million dollars worth of equipment and materials and even though he told me not to worry about it ,,,I did.
Larry

[rdresch]

We can always add enough power for hover. But will it have have enough wing to transition to forward flight?
Rudy

[Tumbler]

Did he pay for that thing out of pocket or was it some gov't funded project or something?

I am starting to get real worried now. 10ozs for the airframe, 10 for the heli mechanics, 4.5ozs of the battery, plus servos and rx etc. I don't this is going to work. I think 25ozs would eb the max and I will be over that. hmmm

[v22chap]

Nope ,,it was private funded ,,over 20yrs ,, he and his now departed father owned a machine shop and was doing it trying to maybe land a government funding to continue the project for government UAV's .They even made there own carbon fiber props and prop cone that would colapse under a certain impact pressure for saftey's sake.

You may have to rethink some of the design and see if you can cut more corners.This is the reason that I had to go bigger and is also the reason Rudy has went just a little bit bigger yet.
Good luck
Larry

[Tumbler]

Yeah, I am at a crossroads, do i finish what I started or start over. I don't know for a fact that it won't work, so i guess should finish it and at least give it a whirl. If it doesn't have enough power, but is close then I can go brushless. If it isn't even close then will have to start over. I really like the way it looks, which ironically has caused the weight problem.............woorying too much about the cosmetic appearance and adding too much filler, etc.

I will forge ahead and keep you posted.

[rdresch]

This is the issue as I see it. Between all the electrics and extra mechanics a V22 is going to be heavy. Add to this the fact that scale wise the wing is very small. So now we have wing loading that is double what we would wish for. Getting enough power to hover is not the problem. Getting enough lift to transition to forward flite is.
Two issues here. First if you use heli type blades that helps the hover, but it is not efficient for forward flite. The blades need more pitch as forward speed increases. Second is the wing loading problem. Only solution is either more airspeed or more wing.
If you look closely at the real Osprey it has many aero devices to preclude stall at lower speeds. Now if We had several million dollars and the right computer software and a wind tunnel and 30 or so top engineers we could probably do the same.
To sum it up, a true V22 built to near scale that hovers and transitions is a incredibly difficult and overwhelming task. Be prepared to spend much time (and money). I think it is possible, but I could be wrong. Just my opinions
Rudy[COLOR=Black]

[Tumbler]

Yes I think everything you said is absolutely right. I mistakenly thought by going electric the weight would be less and could overcome te problems of transition by hanving a lighter wing loading.........WRONG!! haha.

You are right, the xv-15 and Osprey are like flying buses with lots of drag. When I start my next attemp and I am sure I will have to at some point, I will use the BA 609 as my airframe, as it is much less draggy. i honestly wish I would have used this design for this one, but thought the fuse would be more work. Looking back, it wouldn't be anymore difficult..................doh!

Brian

[rdresch]

Tumbler, I made a major mistake in mine by building a Turbine (expensive).
If I had it all to do over again I would build a electric with lipos and brushless. I would use a couple Trex heads and frames modified to work. Everything is way cheaper and I wouldn't be so afraid of a crash. Plus it would be easier to make changes. On yours could you make a plaster mold from your fuelage and then use that as a form to vacume a thin lexan fuselage? It would save a lot of weight?
Rudy

[Tumbler]

Rudy,

Thats you doign the turbine version...you are sick! haha

I hear you on the plastic fuse, however if you think about it, my fuse was ony 3 ozs before i added all the plywood for reinforcements.........loanding gear and wing mounting. I would have to do that with a plastic fuse as well. Half the weight is the wing which i can't make any lighter if I tried.

I think you are right, the Trex mechanics would be good. More expensive than what I am doing, but waaaay less that the project you are working on.

Can't wait to see that thing!

[v22chap]

Welcome to the fight all ;) :eek: :D I have been doing this off and on for 18 yrs now and am so close that I can taste the full conversion everytime I fly mine ,,but alass it aludes me everytime . :o
I have opted for the not so scale extra wing and more power and think that it will be the answer if I can just re engineer the nacelle mounting that let go last time and also maybe get a better system for the conversion switching (the TH-2 GP) and let the pilot pay more attention to flying.

Brian I would guess that yours would work if you went brushless and 4 s lypo's ,,but then you are talking big bucks too.

[Tumbler]

My plan is to mix the flaps to the rotation sequence and have the gyro rotate with the rotors so there is a s little thinking as possible. I don't want to be fumbling around with switches either.

Do you think if you had the mechanics covered up with nacelles it would help you by providing more lifting area?

If I go brushless the power is limited only to what the blades can handle as they are not meant for very high rpms. Eventually I planeed to go that way, but would love to have things work with the brushed motors first.

[v22chap]

Brian
The flaps can be made to come up with your stunt switch ,,which is the switch I use for the start mode of the conversion.Position one starts the tilt to 60 degrees and brings flaps from 68 degrees to 40 degrees.Then position 2 shuts off heli controls and brings flaps to airplane mode.

Do you think if you had the mechanics covered up with nacelles it would help you by providing more lifting area?

Yes and I also am changing the gearboxes around so they will be narrow like they should be,this will cut down on the drag as they will go from 6.5 " wide to about 3.25.
My biggest problem now I think is the lack of good gearboxes and pilot training :eek: ;) :rolleyes: :D
Larry

[Tumbler]

sorry Larry, I just saw your last post. I am using a JR 10X which doesn't have helicopter functions so I have some limitations. I do havce flight modes though and I am sure I can do it.

If I have the gyro rotating with the motors, at 60 degrees the gyro will be on a 45 degree angle. what do you think this will equate to in control response?

[v22chap]

At 60 degrees the tilt arm mounted gyro is going to still keep the heli roll axis level and is going to start to work on the yaw of airplane mode ,,,so far it has really made my bird more stable through out my flight .Before I would get really bad wing walking in heli and 60 degree mode ,,but since this mod it has all but stopped.

[Tumbler]

At 60 degrees the tilt arm mounted gyro is going to still keep the heli roll axis level and is going to start to work on the yaw of airplane mode ,,,so far it has really made my bird more stable through out my flight .Before I would get really bad wing walking in heli and 60 degree mode ,,but since this mod it has all but stopped.

Cool thanks Larry. Here's where I am so far. I am doing this rarely seen scheme in the pic.

Brian

[v22chap]

Great looking ,Brian ,, hope those blades work for ya.
Larry

[Tumbler]

a little more color added today.

[rdresch]

wow! starting to look really good.
Rudy

[Tumbler]

Thanks Rudy!

Worked all night and got box gearboxes done. Lengthened the main shaft and mounted the motor under the spur gear to lower the CG of the heli mechanics. Because the motor is in front, it still wants to tilt forward but there is nothing else I can do.

She'scoming along. Hope to fly it next weekend!

[Osprey WannaB]

She looks wicked man... lets just cross our fingers and thumbs and hope it will hover and do a lot more... just one question... are u goin to be using collective pitch ?? and/or full heli functions... eg pitch roll and yaw In heli mode??? thats wat i'm hoping for in my project?

[Tumbler]

She looks wicked man... lets just cross our fingers and thumbs and hope it will hover and do a lot more... just one question... are u goin to be using collective pitch ?? and/or full heli functions... eg pitch roll and yaw In heli mode??? thats wat i'm hoping for in my project?


Thanks! I am not even trying the stock motors and going right to brushless so it shhould hover....i hope :confused: I won't try a transition at all until I have the nacelles done thoug as I am sure it needs all the lifting area it can get.

Mine is fixed pitch. motor speed controls altitude and aileron, the pitch servos are mixed together to get yaw control.

Brian

[rdresch]

Oh Yea, Best of luck. Keep us updated
Rudy

[v22chap]

Brian ,, looks good ,,,keep us posted on it hover test

[Tumbler]

well, I ran up the first motor last night. Holy Crap its got power! I am using 4200KV brushless motors, which are not right for this thing. waaaaaay too strong. Better to have too much power right? The airframe weighs 10ozs ok? The one motor by itself lifted itself attached to a 10oz clamp, the 5 oz battery, and the watt meter. This was all at less than half throttle and only drawing 11amps! I had to adjust the throttle curve because going above half throttle made the blades cone up so bad and thought it was going to explode! Looks promising thus far!

Brian

[v22chap]

Sounds good ,,keep the curve down so you don't expode the gearboxes. :eek: :D

[Tumbler]

Sounds good ,,keep the curve down so you don't expode the gearboxes. :eek: :D


that plus the fact I am only using 3mm carbon rods for the main shafts so if they get jerked violently i am sure they will snap. :eek:

[Tureck]

Hi Brian,
I had to check out your build thread after i saw it at the field the other day! Outstanding craftsmanship! I may want to try something like this with some Blade mechanics. Oh boy... more stuff to buy. Hope you get it ready for this weekend!
Again... Fantastic Job!!!

Bob

[Tumbler]

Hi Brian,
I had to check out your build thread after i saw it at the field the other day! Outstanding craftsmanship! I may want to try something like this with some Blade mechanics. Oh boy... more stuff to buy. Hope you get it ready for this weekend!
Again... Fantastic Job!!!

Bob


Thanks Bob!!

Yeah I would like to try a slightly larger version with T-Rex parts if all goes well. I wouldn't use the heli blades though. Whith those blades I don't think it would have a prayer in forward flight. I thought about buying like 22" props and making my own twisted carbon blade molds but realized its going to be hard to find a pusher prop that big to make a mold out of.

money money money!

Brian

[MustangAce17]

thats the main drwaback to these projects,the money issue but mine now flys so I'm sure 100% yours will be excellent.thanks for all your help Brian and good luck

[Tumbler]

Well, I just got the new couter-rotating blades. They are pretty. Definitely going to make a mold I think just in case I break one. At $70 a pair thats too expensive to replace a set.

[v22chap]

Woooo, those look nice ,,and should do the job ... let us know what you think of them ,,,and let us know if you start producing them :D

[Tuner]

Glad to see you got those blades Brian.

Right ON!

You are on the right track with the TREX parts would work great just bought a TREX SE nice kit.
A suggestion and what I will try at some point is to use the TREX Heli Head and Swash Plate . But Do not use the Mechanical mixing nor the Fly bar.

The key hear is to use your radios exponetial controls or short sevo arms to reduce the sensitivity of the controls. But it may be to unstable. If not this will save you weight and will reduce the Length of you Prop Shaft and in doing so reduce the torque needed to rotate it and probably make a more scale looking design.

I do not see a need for anything other than variable pitch fore, aft, left, right cyclic is not needed though I could see how it might be useful.

[Tumbler]

Glad to see you got those blades Brian.

Right ON!

You are on the right track with the TREX parts would work great just bought a TREX SE nice kit.
A suggestion and what I will try at some point is to use the TREX Heli Head and Swash Plate . But Do not use the Mechanical mixing nor the Fly bar.

The key hear is to use your radios exponetial controls or short sevo arms to reduce the sensitivity of the controls. But it may be to unstable. If not this will save you weight and will reduce the Length of you Prop Shaft and in doing so reduce the torque needed to rotate it and probably make a more scale looking design.

I do not see a need for anything other than variable pitch fore, aft, left, right cyclic is not needed though I could see how it might be useful.


The blades don't work as well as the stock blades actually. The carbon blades have too much pitch in them and bog down the motor and draw a lot more ams. Not sure what I am going to do now.

Sounds like interesting idea with the TREX parts. Let me know how that works out!
Brian

[v22chap]

Brian
I am sure that you probably done this ,,but just to double check ,,, make sure that you have way less pitch with these twisted blades as when I made my twisted blades I had to lower the pitch alot. Mine are -3 now instead of a +6 (measured at the tip ) when I am in the hover position (1/2 stick),, and yours might even need less .They really provide a lot better lift than normal blades.