Thank you, I'll create a playlist so it's in a better order.

Thank you 👍

Thanks 👍 You will be balancing your rotor any time soon. As you have lead/lag adjustment you will be able to get the chord mass in the centre. Then it will come down to how accurate the machining was on the rotor hubs. Looking forward to your next few videos and seeing how you tackle it.

Thanks for the comment. hope it helps 👍👍

Interesting, with the reduction in noise and vibration was the efficiency of thrust affected ?

I haven't actually tested it, but theoretically, I don't think it will be affected by thrust.

Thanks for the inspiration Cam, it's because of people like you that I've got this far. Hope you're still tinkering. Interesting comment on the blade rising. 😀

Thanks for the comment 👍

Well it has its merits, but there are better designs. The new mosquito blades are the design to strive for in my opinion. Got to get that chord mass at 25%.

That's correct, it must balance at the aerodynamic centre and I would agree that mounting the blade at this location is sensible. However I don't think Robinson mount the blade here, they are mounted further back and there is a benefit to doing this. It was explained to me but I can't remember the reason now.

You're welcome I'm still learning too 👍

Thank you, yes collective would be better I think, if I had twin engines as well that would be even safer. Ground resonance I believe can only happen with more than two blades on the same hub. Dont think it can happen on a coaxial with twin teetering rotors.

Thanks. A friend of mine said about doing it that way but was probably first done by the Romans. Not for rotor blades of course but other levelling jobs. 😉

Yeah, everything takes ages, but the next test and video will be exciting (for me at least). I'll put on a head cam so you can see what I see. Will be so pleased if it can demonstrate the required lift.

Hi, yes determining the service life of a component is difficult. These particular blades weren't used as I made some much lighter ones. The new blades have a spar with a cross sectional area which will take the centrifugal loads at the materials fatigue strength. Parts built to this strength will not have a limited service life. However that's only centrifugal loads where actually there are other load factors like twisting and blade bending. These would reduce the life. Perhaps the only way to find out some numbers is to have a mechanical jig for testing blades running 24/7. This of course is very expensive research and beyond my means.

👍

Thank you very much 🙂

The reinforcement plate, I think you are referring to, what I would call the spar is aluminium 6082t6

Thank you 😊

Thank you 😊

@@Ben-Dixey.....:) ....knowledge is power ....

You're welcome 👍

Hello, I've done a video on how I made my blades m.kzfaq.info/get/bejne/ZrtonLCI0t7Lf2Q.html The blades in the balancing video I made but are too heavy for my coaxial helicopter, they would be ok for a single rotor with collective pitch. They were made by folding the skin around the aluminium spar. The spar was solid aluminium 6082t6 and milled to better fit the aero foil shape, then the skin was fixed to the spar with 3m double sided tape. This design was also too tail heavy with its chord mass at 31% it needs to be 25% in order to spin safely. This is partly why I changed the design but the balancing procedure is the same.

The Gyrotor instructions for blade chord balance said to have the blade straps and blade retaining bolts in place, this makes sense to me but I am happy to be persuaded otherwise. Tip weights is something I would definitely consider. Thanks for the comment.

How much should be tip weight need to add?. Is there any standard calculations?

@@prash007more I believe tip weights are sometimes added to reduce cyclic control sensitivity. They are sometimes used on gyrocopters and helicopters. I don't know if they will be necessary on my coaxial, I won't know until I try it. I'm hoping they won't be needed as it changes the centrifugal forces on the blade and the coning angles.

Yes. Love my old lathe, I found it for sale 1/2 a mile down the road and paid £200 for it. I put on a digital read out and a digital phase inverter. It will probably last a lot longer even having been built in the 50/60s. These blades aren't going to be used, I just used these for the balancing demo, the blades on the helicopter have inserts in the ends to prevent centrifugal air pumping which will drag the blades by a few hp. Rounded ends I'm sure would be even better but don't know by how much.

Hi and thanks, yes the bolt needs to be balanced in its position. I didn't use this rotorhead in favour of a different design, the new design has studs which are the same length and the same nuts both sides. It's just like balancing a wheel where all positions in a 360 circle must have the same mass from the centre of rotation. Where you can't add weight the centre position needs to be altered with shims instead. A out of balance centre bolt will affect the shimed position.

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Yes goods keren kreatip buat helikopter ?

Hi, no autorotation is possible and at the height I'm operating autorotation wouldn't be much of an advantage as it takes 50-75ft to transition from powered flight to auto.

Hi, thanks for the comment, I've been thinking about doing a rotor strength video, there are a bunch of calculations i did to determine such things as rotor hub thickness, blade strap thickness, rotor spar strength, bolt shear strength ect. I can only determine these values in a basic calculation and you could go much further than I did using cad and stress analysis. I'm no expert but could share my basic understanding.

@@Ben-Dixey thanks

Thank you. Yes that's correct the blades are fixed in pitch and engine rpm is used to control lift. It's not as precise as using what's called collective pitch but it's still effective. Have a look at the Nolan helicopter this is where the inspiration came from., m.kzfaq.info/get/bejne/eJhhi85n2bTHcqs.html

@@Ben-Dixey actually even with fixed pitch it's looked quite controled and stable .. But you can change the position of rotors on their Axis ? To get the cyclic control ?

@@rajeevshagun7409 yes, you have got it. It keeps things simple and lightweight but there is a drawback which is control. With cyclic pitch control using a swash plate it's very sensitive and responsive. With a tilting mast there will likely be a time delay between control inputs and response. I will have to learn to compensate for this but as the Nolan helicopter demonstrates it's very controllable once you have mastered it. I will soon find out what it responds like as I'm getting ready for the next test.

@@Ben-Dixey oh my best wishes are with you ... Don't need to remind you the safety procedures , because you are well aware . The good part of contra rotors is , it has very little chance to get wild spinning due to anti torque rotors failure . Almost no chance . I have seen wild vibrations in main rotors in new copters . But your stuff is balanced blades we can trust it . I wish I would be around you that time .

@@rajeevshagun7409 Thanks for the encouragement. I will be recording the final testing procedures and then 🤞learning to fly it so everyone can experience it with me. 👍

Thank you. A follow up to blade balancing ? For me the process in the video worked and I haven't had to do any further work on balancing. Dynamic balancing would probably be the next step or perhaps fine tuning the method of chord wise rotor balancing.

@@Ben-Dixey All right then. 👍

Thanks so much for the comment. I like to help if I can.

Thanks Jeff, tracking is done by spinning the rotor blades at flight rpm with some pitch but not enough to take off, adjustments are made on individual blade pitch so that they rotate in the same plane. I haven't done any tracking yet but I need to do it next test. Every rotor needs to spin on its centre of mass just like a wheel needs to spin on its centre of mass. When a car wheel is balanced you add weight to one section of the wheel this is because you can't change the wheels centre bolting point. With a rotor we can add weight like a wheel to the blade tips as a little weight makes a big difference over the length of the blade but much more weight would be needed to balance in the chord direction. Instead the rotor is shifted from its normal axis with shims. Alternatively you can lead or lag a blade in order to change its chord-wise mass distribution. No matter how accurate your blade retaining bolt holes are there will be a slight deviation at the blade tip to where it needs to be to balance. I'm not sure if the furia plans have included teeter hinge shims but it would be good to include them so you can get that rotor spinning with minimal vibration.

@@Ben-Dixey I see later on realised actually tracking is all about connecting rods and blade flaps adjustments...while what you did was rotor balancing itself...it's a good illustration will sure borrow some tips when my time comes...seems for my case I will need to dismount the entire rotor head and balance it with blades since they can't be dismounted seperately as your case....the easiest way for me with blades is using tubes and bars as shown in the plans...did one pic post with a prototype trying to figure out tube sizes...

Hello Ben, well been a while, just a quick one. Currently balancing my blades, and according to your video the washers are placed at the tip, I watched another RC blade balancing video and the guy says the weight should be added at the COG of the blade, as adding anywhere else offsets the individual blade initial COG....does that make sense? Cheers.

Hi, yes there will be a radiator and belt driven fan for cooling but for testing purposes I just have a water reservoir and electric pump.

Hi, yes that is correct, the blades and hub in this video were not used. I just used them for the balancing demo. The CG location of the blade with blade straps and balancing was done in the same way on the new blade sets.

Thank you 👍

Hi, the center of pressure of a 0012 blade (also called the aerodynamic center) is 25% chord, this is why the center of mass of the blade also needs to be 25% chord.

@@Ben-Dixey thank you

I agree with you, it's a conversation I've had many times with people and assessing the risks is difficult. I believe Munna was unlucky but had he been wearing a seat belt or a helmet I think things would have been different. I also would ask did he do the centrifugal force calculations on the tail rotor, did he use materials of known specification, did he run the tail rotor at higher rpm to check the strength under guarded conditions ? These would all be measures to try and avoid a rotor separation. I have done these things but I know full well there are other parts that could fail and you can't remove all the risks. I have gone back and fourth in my thoughts on whether or not to play with a homebuilt helicopter.

Rotor diameter is 4.3m, each blade is 2m long.

@@Ben-Dixey Thank you sir

Yaw controls will be through directional vanes on the tail using the rotor downwash. check out this kzfaq.info/get/bejne/eJhhi85n2bTHcqs.html

thanks to you and ur gpod intention of making people smarter

Always thought directional control on coaxial is achieved by varying blades speeds...?!..or vanes is an alternative way of doing it

@@JeffChoppah altering blade speed for yaw is an interesting idea, I've heard of using a differential for driving the rotors and braking one rotor to achieve yaw but the craft would also reduce in lift which wouldn't be ideal. In a variable pitch coaxial you can increase the pitch on one rotor and decrease it on the other that would produce yaw but keep the lift the same. The tail fins on the Nolan helicopter seemed to work well and it's definitely the simplest solution. Time will tell if it's the right decision.

Hi, I can't share my drawings in case there is something wrong with my design. When it's been proven for hundreds of hours then I would consider it. I wouldn't want anybody copying any potential mistakes.

25% is where the centre of pressure is located on a naca 0012 aerofoil. If the balance is not at 25% then forces will be present in the collective stick. Weight either side of 25% will cause the blade to want to go to 0 pitch.

Initially I had the synchronous belt pulleys made as toothed blanks and I machined the spokes to make them as light as possible but when I changed the ratios I made the drive pulley from scratch. I made a fly cutter for the milling machine using Hss tool steel ground to shape by hand but using a profile projector to get the contour accurate. This video shows a bit more. kzfaq.info/get/bejne/r7uUbLmYnryUoX0.html what sort of ultralight project have you got in mind ?

@@Ben-Dixey something along the lines of an affordaplane or legal eagle maybe even airbike basically want it to fly like a cub

@@chrisknasel23 sounds fun 👍

That is a huge question to answer and I can't answer it. There is guidance on rotor blade size if you look up disc loading, solidity ratios, and aspect ratios. But ultimately what I did was copy what someone else had done. If you can find an example of a 30kg helicopter and its rotor dimensions that is. 30 kg is very light are you making a model ?

😆thank you.

Hi, it has cost £6000 in materials to build.

Hi, it's 0012