three blade intermesher helicopter

This is an animation of a three blade (per mast) intermeshing helicopter rotor system. Most intermeshing designs, such as the Flettner 282, the Kaman H-43 Huskie and the Kaman K-1200 Kmax are two-blade designs that use a teetering rotor hub. In the late 1940's the Kellett Autogiro Corporation designed and flew the XR-8 and the XR-10 and these were both three-blade intermeshing helicopters with fully-articulated rotor rubs. The animation in this video is modeled after the XR-10.
Link to CW Bayer's tribute to his father who test piloted the XR-10
www.nevadamusic.com/?page_id=...
Videos of the XR-10 in flight
• Kellett XR-10, 1947
• Kellett XR-10, 1947
Images used in this video
FL-282
commons.wikimedia.org/wiki/Fi...
H-43 Huskie Helicopter
commons.wikimedia.org/wiki/Fi...
upload.wikimedia.org/wikipedi...
USAF (Released to Public), Public domain, via Wikimedia Commons
K-1200 Helicopter
commons.wikimedia.org/wiki/Fi...
upload.wikimedia.org/wikipedi...
André Völzke, CC BY-SA 3.0, via Wikimedia Commons
Kellett XR-10 Helicopter
en.wikipedia.org/wiki/Kellett...

[@Beef3D]

fun fact, when I was on holiday in Switzerland back in 2010, I witnessed a Kaman K-Max for the first (and last) time. not only did it make the weirdest helicopter sound ever which obviously was produced by the intermeshing rotors... it also landed in a field only 100 yards away from wher I was standing when I observed it approaching.

[@bzig4929]

Every time I see them, I think... "something isn't right", and then, "this has to be one of the coolest helicopters ever flown". Thanks for watching.

[@dudleysmith5111]

Another issue that may have contributed to the blade contact in the XR-8 could have been the the direction of rotation of the two rotors (I need to check their direction of rotation.). When viewed from above, if the right hand (starboard) rotor is rotating clockwise, its advancing blade is over the port side of the helicopter. In forward flight the advancing blade would then flap up and away from the port hub increasing the physical clearance. Similarly, the port rotor (when viewed form above) would be rotating counter-clockwise (to eliminate the torque) with its advancing blade over the starboard side of the helicopter. In forward flight the blade would flap up and away from the starboard hub, increasing the clearance. This is the case you presented in your animation. It would be interesting to see the variation in clearance of this case with the case of the rotors with the alternate rotation arrangement. Again, your work is very impressive!

[@bzig4929]

Good observations. I have to think you are correct in the reason they chose the rotation directions.

[@tsclly2377]

a good drone configuration

[@dudleysmith5111]

It’s great you modeled the flapping motion to show the (non) interaction of the three blades with this motion. Could you possibly add the lead-lag motion too? The testing reports on the XR-8 indicated blade contact marks near the blade-hub attachment region which occurred in rapid maneuvering flight and could have been a result of the lead-lag motion and blade aeroelastic deflections. Very impressive work.

[@bzig4929]

That sounds like a cool addition. The animation software (blender) allows me to drive the blade motion with python code. I have this vision of really increasing the level of complexity. In this video I was just adding flapping in a 2-per rev sin wave. All I need is time 🙂. Thanks for the comment.

[@Nemezidych_Killer]

Well, synchropters from the Command & Conquer game series (GDI Hammerhead from C&C 3: Kane's Wrath and USSR Twinblade from Red Alert 3) no longer seem like fiction.

[@dudleysmith5111]

Just checked an old video and it appears the XR-8 rotors rotated starboard clockwise and port counter-clockwise.

[@bzig4929]

That aircraft amazes me. I know it wasn't operationally successful... But the fact that they built it, and flew it, in the 40's, is incredible.

[@user-jq2rf4nf3o]

Kellett found during tests that those blades were brushing against each other - and the speed of these type of helicopters were slow. Kaman went to the H2 single rotor for speed - and It actually costs more to manufacture -Mirrored systems and material needed for manufacture X2- Tail rotors have positive yaw control power a coaxial or syncrocopter have issues. great animation

[@bzig4929]

I'm fascinated by Kellet story. It's hard to imagine this was desiged and flown in 1944. Even though it never flew in service, the fact that it flew at all is a tribute to some smart people.

[@user-jq2rf4nf3o]

@@bzig4929 and twin engines too!

[@joshdenton611]

awesome video man!😉😎

[@bzig4929]

Thanks! 😁

[@Dstructeur1]

I just posted a comment on another of your videos stating I’d love to see how they’ve done the chinook sorcery, awesome I see this one right after! I assume it is the same idea or very similar ?

[@dedawiawi2201]

The two-bladed synchrocopter has a rotor camber angle of 12.5 degrees, in my opinion. And what is the angle of collapse of the rotors with three blades?

[@nepaliman5716]

What are the advantages over regular helicopter? Can carry more load?

[@bzig4929]

More load is the idea. Tail rotors use a significant amount of power. Tandem and intermesher helicopters don't need tail rotors so all the power is turned into lift production.

[@hoodio]

humans are determined to build the most dangerous vehicles, xd

[@ImraneMokhtari-wi4hq]

No production! Too many neighbors complain?